جستجوی مقالات مرتبط با کلیدواژه « جوجه های گوشتی » در نشریات گروه « علوم دام »

During the last stages of incubation, avian mortality commonly happens due to the lack of enough nutrients and amino acids (Fardoost et al. 2019). However, in ovo injection or in ovo feeding is considered a new technique for improving growth of chickens (Ebrahimi et al. 2017). Most studies indicated improving effect of in ovo feeding of nutrients (especially amino acids) on small intestine growth and histology as well as higher absorptive capacity of digestive system (Ebrahimi et al. 2017, 2018a,b; Elwan et al. 2019; Fardoost et al. 2019). Previous studies indicated an improving effect of excess feeding of arginine on growth performance, carcass traits, blood metabolites, and intestinal histology of broilers (Ebrahimi et al. 2013, 2014, 2016b). However, there are few records regarding the impact of in ovo injection of arginine on intestine histology of chickens. Accordingly, the present study was designed to evaluate the effect of in ovo injection of different levels of arginine on carcass traits, blood metabolites, and small intestine histology of broiler chickens.

For this reason, 300 fertile broiler breeder eggs were divided into three treatment groups: 1- 0.5% L-arginine in ovo injection group (100 eggs), 2- 1% L-arginine in ovo injection group (100 eggs), 3- control group included distilled water injected (sham-control subgroup, 50 eggs) and non-injected (control subgroup, 50 eggs). Eggs were then set into the incubator for the first 18 days with the temperature of 37.8°C and six rotations per day. At d 14 of incubation, eggs were injected into the amniotic fluid (Ebrahimi et al. 2017) as follows: 1- in ovo injection of 5 mg L-arginine/ ml distilled water, 2- in ovo injection of 10 mg of L-arginine/ml distilled water, 3- control group included sham-control (in ovo injection of 1 ml distilled water) and control (received no injection). For in ovo injection, solution pH was set at 7.0. At d 18 of incubation, eggs were moved into hatchery boxes. After hatching, chicks were reared for 24 days. During the experiment, chicks received standard commercial diets based on Ross recommendations as starter (0-10 days) and grower (11-24 days), (Table 1). At d 24, blood samples of three chickens per each replicate were collected, centrifuged (3000 rpm for 20 minutes), and serum was separated to evaluate cholesterol, glucose, triglyceride, uric acid, and total protein by the Enzymatic Colorimetric method (Ebrahimi et al. 2017). Then, all birds were weighed, slaughtered, some carcass traits (scalped carcass, eviscerated carcass, breast, thigh, gizzard, proventriculus, pancreas liver without gall bladder, heart, duodenum , jejunum, and ileum were weighed, and their relative weight to chicken body weight were calculated. Also, length of duodenum , jejunum, and ileum was evaluated and their samples were stored in 10% formalin for fixation to evaluate histological parameters (crypt depth, villus height, villus thickness, mucosal thickness, and crypt diameter) using Hematoxylin - Eosin staining method (Ebrahimi et al. 2017). Then, villus height to crypt depth ratios were calculated. Afterwards, data were analyzed based on a completely randomized design by the Proc GLM of SAS software (Ver 9.2). Also, Tukey-Kramer test was used for comparing treatments and results presented as least square means ± standard error.

Based on the results, in ovo injection of different levels of L-arginine did not affect hatchability, day-old chick weight, chick weight to egg weight ratio, 24-day-old chicken weight, feed conversion ratio, relative weight of all carcass traits, cholesterol, glucose, total protein and blood urea nitrogen (P> 0.05), (Table 2). However, serum triglyceride was significantly affected by experimental treatments (P <0.01) and the highest amount was observed in 0.5% L-arginine in ovo injection group (Table 2). In a similar study, Gao et al. (2017) indicated that L- arginine in ovo injection increased weight gain of broiler chickens. Furthermore, Abdolalizadeh Alvanegh et al. (2017) reported the improving effect of in ovo injection of different ratios of L- arginine to L- lysine on chick weight and their carcass traits. Also, they reported higher serum total protein level, while lower blood urea nitrogen of broiler chicks with in ovo injection of different ratios of L- arginine to L- lysine (Abdolalizadeh Alvanegh et al., 2017).Present results indicated no significant effect of in ovo injection of L-arginine on most weight and length parameters of small intestine length (P>0.05); however, relative weight of jejunum was significantly affected by in ovo injection of L-arginine (P<0.05) and the highest amount was observed in 0.5% L-arginine in ovo injection group (Table 3). Present results indicated no significant effect of in ovo injection of L-arginine on duodenal crypt diameter; jejunal villus height, crypt depth and diameter, and mucosal thickness; and ileum villus height, crypt depth, villus height/crypt depth ratio, and mucosal thickness (P>0.05), (Table 3). However, significant effect of in ovo injection of L-arginine was observed on duodenal villus height, villus thickness, crypt depth, villus height/crypt depth ratio, and mucosal thickness; jejunal villus thickness and villus height/crypt depth ratio; and ilium villus thickness and crypt diameter (P<0.05), (Table 3). Also, the highest amount in most histological parameters was observed in 1% arginine treatment (Table 3). In a similar study, it was reported that in ovo injection of L- methionine had a positive impact on small intestine length and weight with improvement in villus height, crypt diameter, crypt depth, and villus height/crypt depth ratio of duodenum and jejunum (Fardoost et al. 2019). Also, in ovo injections of L- lysine improved histological parameters of duodenum, jejunum, and ileum (Ebrahimi et al. 2017). Ebrahimi et al. (2018b) with in ovo injection of different DL- methionine to L- lysine ratios reported higher small intestinal weight and length along with higher Villus height and Villus height to crypt depth ratio.

Based on the overall results of the study, injection of 0.5% arginine showed a positive effect on the growth and small intestine morphology of broiler chickens.

In the past studies, the beneficial effect of insoluble fiber in broiler feed has been well demonstrated. Studies have shown that moderate amounts of fiber in poultry diets lead to significant improvements in nutrient utilization efficiency. Depending on the type of dietary fiber (soluble or insoluble), the particle size plays a role in the growth and development of gizzard and improves the mixture of digestive substances with digestive secretions. On the other hand, nutritionists are trying to respond to the rapid growth needs of birds by increasing the energy concentration of diets. Fats are considered for this purpose, as their energy value is at least twice that of carbohydrates and proteins. At a young age, the secretion of bile acids and the activity of pancreatic lipase are low, and therefore, the ability to digest fat in young broilers is compromised. Some studies have shown that cellulose and oat hull as a source of insoluble fiber (3%) in the diet of broiler chickens have increased the apparent digestibility of crude fat in the ileum and increased the availability of energy for the bird. Therefore, the purpose of this research is to investigate the effects of sunflower hull with different particle sizes in diets containing different sources of fat on growth performance, digestibility of nutrients and the microbial population of the caecum of broiler chickens.

This experiment was conducted using 360 one-day-old Ross 308 broiler chickens in a completely randomized design with a 2×3 factorial arrangement for 42 days. Experimental treatments included: sunflower hulls (SFH) (without hulls, 3% with 1 mm particle size and 3% with 5 mm particle size) and different fat sources (3% tallow, 3% canola oil). Feed intake (FI) and body weight gain (BWG) of birds were recorded and feed conversion ratio (FCR) was calculated. To determine the ileal digestibility of nutrients, 3 g/kg of chromium oxide was fed to chickens on days 37-42 of the rearing period. On the 42nd day of rearing, the ileum contents of 2 birds were collected and stored in a freezer at -20◦C. To investigate the morphology of the small intestine, 5 cm of the duodenum, jejunum and ileum were taken. Cecal microbial population also determined at 42 days of age. The data obtained from the experiment were analyzed using SAS statistical software and GLM procedure. To compare means, Duncan's (1955) multi-range test was used at a significant level of 5%.

The results showed that, using of the coarse and fine SFH in the diet of broiler chickens increased FI and improved the FCR in the whole period of experiment (P<0.05). Canola oil improved FI and BWG compared to tallow (P<0.05). Apparent digestibility of crude protein and crude fat also increased by using of coarse SFH in the diet (P<0.05). The use of coarse SFH increased the villus height of duodenum and the villus height and thickness of ileum (P<0.05). Canola oil increased the villus height of ileum, but decreased the villus thickness compared to tallow treatment (P<0.05). The use of coarse SFH in the diet reduced the population of Escherichia coli bacteria in the cecum, and coarse SFH with different sources of fat increased the population of Lactobacillus (P<0.05).

In general, the results of the present study showed that the addition of coarse sunflower hull to the diet could improve the growth performance of broilers by increasing the digestibility of crude protein, crude fat, Lactobacillus population, and reducing the cecal population of E. coli. Although its interaction with canola oil also had positive effects on the population of beneficial gut bacteria.

Guanidinoacetic acid (GAA), a creatine precursor, is synthesized from L-arginine and glycine. The capacity for de novo synthesis may be limiting in high-yielding farm animals, especially in those fed all-vegetable diets. As the precursor to creatine, dietary GAA can also effectively “spare” arginine from being used for GAA synthesis, so that the arginine may be used for muscle accretion and other physiological functions. It has been reported that arginine affects bone development by its involvement in the formation of collagen and connective tissue. It also has been shown that reducing the protein level in broiler diets reduces the concentration of manganese and copper in the tibia. Therefore, low-protein diets probably decrease bone density in broilers. This study was conducted to investigate the effects of GAA supplementation to low protein diets on performance, calcium and phosphorus and the strength of the tibia of broiler chickens.

  The 240 male broilers of Ross 308 strain were assigned to 6 dietary treatments in a 3 × 2 factorial arrangement with 4 replications and 10 birds in each replication. Dietary treatments included diets containing 80, 90 and 100% of the breeder recommended ideal protein each containing 0 and 0.06% of GAA. Feed intake, body weight gain and feed conversion ratio (FCR) were measured for the grower (11-24 days), finisher (25-42 days) and the overall period (11-42 days). On d 42, two birds from each experimental unit were killed, and the ash, calcium and phosphorus content and the strength of the tibia of the chickens were measured.

The results showed that by reducing the ideal protein to 80% of the breeder recommendation, body weight gain and feed intake was reduced significantly (P<0.05). Reduction of the dietary CP from 100 to 80%, resulted in inferior FCR during grower period. The inferior performance of broilers fed reduced protein diets is attributed to a limited availability of amino acids (AA). The supplementation of essential AA alone has failed to increase performance in reduced protein diets. The addition of GAA decreased feed intake of treatments (P<0.05) with reduced protein diet (80% of management guide recommendation). Body weight gain and FCR were not affected by dietary GAA supplementation. By reducing dietary protein to 80% of the recommendation, the strength of tibia decreased significantly (P<0.05). A low-protein diet may be associated with a hypocalciuretic effect, increased Ca retention and requirement for available P to avoid Ca:P imbalance, hormonal flux, and bone mobilization. Addition of GAA to the diet did not affect the parameters of bone strength. Tibia ash, Ca and P content were not significantly affected by dietary treatments.

According to the results of this experiment, reducing the dietary ideal protein to 80% of the breeder recommendation, resulted in inferior growth performance and tibia strength of broiler chickens, and dietary addition of GAA did not ameliorate those effects.

Effect of different sources of probiotic and prebiotic on growth performance, carcass characteristics, intestinal microflora, and blood metabolites using 720 Ross 308 commercial male broiler chickens in a 3×3 factorial experiment with three levels of probiotic (without probiotic, probiotic type I and type 2) and three levels of prebiotic (without prebiotic, prebiotic type 1 and type II), in a completely randomized design with nine experimental groups (four replications and 20 birds were studied in each replication. Birds that were fed with diets containing type 2 probiotics had a lower conversion factor (P<0.05). Diets containing prebiotic type 1 as well as diets containing probiotic type II and diets containing probiotic type II and two prebiotics under test reduced serum cholesterol and LDL concentrations (P < 0.05). The effect of the experimental treatments on carcass fat was not significant, but the birds fed diets containing prebiotic type 1 had less abdominal fat (P<0.05). At 21 days old, the population of E. coli in the ileum and ceca of birds that received probiotics, prebiotics, and their combinations decreased (P < 0.05). At 38 days of age, feeding the birds with probiotics and prebiotics and a combination of them reduced the population of E. coli in the ceca and increased lactobacillus in the ileum (P < 0.05). The results of this experiment showed that probiotics or prebiotics assayed in this study have positive effects on the increase of beneficial intestinal bacteria (Acid lactic bacteria), blood biochemical traits, and FCR in broiler chickens.

Ascites is one of the most common metabolic syndromes in today's fast-growing broilers and is associated with rapidly growing tissues and characterized by accumulation of lymph fluid in the peritoneal spaces. Effective factors in the occurrence of ascites syndrome include free radicals in the body such as superoxide, hydroxide, and hydrogen peroxide. By reducing the capacity of the body's antioxidant systems, free radicals make the bird susceptible to various diseases. Free radicals produced in the body by damaging the cell membrane lead to cell death and ultimately tissue damage. Therefore, by increasing cell protection from such injuries, one of the common causes of ascites and heart failure abnormalities can be prevented. In addition, free radicals from oxygen derivatives reduce the half-life of nitric oxide (vasodilating agent), causing a decrease in the ability of vasodilation and providing the basis for the occurrence of ascites. Therefore, it is suggested that the use of antioxidants can prevent ascites and improve performance in broilers. Medicinal plants are among the rich sources of natural antioxidants that do not have the harmful effects of antibiotics and synthetic antioxidants. For this reason, the use of medicinal plant extracts is an important step in animal nutrition to increase the immunity of poultry. The mentioned extracts have strong antioxidant, antibacterial, and digestive properties. Probably, the positive effects of medicinal plants are due to the active compounds found in plant extracts such as menthol, thymol, and carvacrol. This study aimed to investigate the effects of ethanolic extract of sage on the performance, antioxidant status, and blood parameters of broiler chickens under induced ascites.
A total of 450 one-day-old chickens (Ross 308) were reared in the form of a completely randomized design with six treatments and five replications (15 chickens in each replication). Experimental treatments include 1. Positive control group (without inducing ascites and fed with basic diet), 2. Negative control group (inducing ascites and fed with basic diet), 3 and 4. Vitamin C group (inducing ascites with levels of 1000 and 2000 ppm vitamin C), 5 and 6- Sage group (ascites induction with 1000 and 2000 ppm of sage extract). To induce ascites, water containing 1200 mg of sodium (three grams per liter of sodium salt) was provided to the chickens from the 15th day of the experiment. Growth performance parameters including feed intake, weight gain, and feed conversion ratio were calculated for the total period. On the last day of the experiment (42 d), two birds were randomly selected from each cage and after sampling from the wing vein, killed and the ascites index was calculated as the ratio of the weight of the right ventricle to the total ventricles. The mortalities were collected as soon as they were observed and after weighing to correct the feed conversion ratio, were necropsied to investigate the cause of death. Blood and biochemical parameters such as the number of red and white blood cells, hemoglobin, hematocrit, heterophil and lymphocyte, serum triglyceride, and cholesterol, as well as serum antioxidant parameters including the level of malondialdehyde and the activity of antioxidant enzymes including glutathione peroxidase, superoxide dismutase, and catalase were measured. In addition, liver enzymes present in the serum including alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), and alkaline phosphatase (ALP) were also measured.
The results showed that induction of ascites increased the ratio of the right ventricle to total ventricles, mortality due to ascites, feed consumption, feed conversion ratio, and body weight loss (P<0.05). Administering sage extract improved the mentioned traits and vitamin C also reduced the ratio of right ventricle to total ventricles, losses due to ascites (P<0.05). Sage extract and vitamin C moderated the increasing effects of ascites induction on heterophiles, triglyceride, and cholesterol and increased red blood cells, hematocrit, and hemoglobin compared to the negative control treatment (P<0.05). In addition, the induction of ascites decreased the activity of glutathione peroxidase, superoxide dismutase, and catalase enzymes and increased serum malondialdehyde, experimental treatments, especially sage extract, improved the antioxidant status compared to the negative control treatment (P<0.05). Also, the induction of ascites increased the serum levels of aspartate aminotransferase, alanine aminotransferase, gammaglutaryl transferase, and alkaline phosphatase enzymes. The addition of experimental supplements, especially sage, decreased the serum level of the mentioned enzymes (P<0.05).
The results of this research showed that the use of sage extract compared to vitamin C has better results on performance, increasing antioxidant power, and reducing stress of broilers with ascites.

The use of medicinal plants and their derivatives can stimulate feed consumption, increase daily weight, feed conversion ratio, increase shelf life, improve the health and function of the digestive system. It seems that the use of an optimal mixture of several medicinal plants in the diet has positive effects on performance and carcass quality of broiler chickens in comparison to each one. Nowadays, with the popularization of ready-made feed in raising broiler chickens, many breeders tend to add food additives in drinking water. Therefore, it is a question that adding these compounds in feed or drinking water makes a difference. Three commercial plant additives that are used today are Coxan, O.X. Plant, and Entex. Coxan contains oregano (with the active ingredient of menthol) and garlic (with the active ingredients of allin and allicin), O.X. Plant contains savory (with the active ingredients of carvacrol and thymol), thyme (with the active ingredients of thymol and carvacrol) and red pepper oleoresin (with the active ingredient of capsaicin), Entex contains cinnamon (with the active ingredient of cinnamaldehyde), and garlic and eucalyptus (with the active ingredient of cineol). The aim of this research was to compare the effects of using these commercial plant additives (in water and feed) on growth performance, intestinal microflora and morphology and immune response of broilers.
A total of 336 Ross 308 broilers were examined in a completely randomized design with seven treatments, four replications, and 12 chickens per replication. Experimental treatments included: control (without phytogenic in feed or water), Coxan in feed (300 mg/kg) and in water (200 mL/1000 L), O.X. Plant in feed (200 mg/kg) and in water (135 mL/1000 L) and Entex in feed (500 mg/kg) and water (350 mL/1000 L). Daily weight gain, daily feed intake, daily water intake and feed conversion ratio were measured. At 42 days of age, two birds were selected from each experimental unit and after slaughter, the length of the intestinal components was measured separately (duodenum, jejunum, and ileum). To determine the microbial population, samples were taken from the ileum of chickens. EMB culture medium was used to determine Escherichia coli population and MRS culture medium was used for Lactobacillus bacteria. To check the humoral immune response, 0.1 mL of 25% sheep red blood cell solution in PBS was injected into the breast muscle of chickens on the 12th and 29th days of rearing. Blood was taken from the chickens on the 28th, 35th and 42nd days of breeding and the levels of Anti-SRBC, and immunoglobulins G and M were calculated. Antibody titer against Newcastle disease was measured by HI method.
The effect of additives in water and feed on average daily feed consumption, daily weight gain, feed conversion ratio and daily water consumption was not significant in the whole period. Since the amount of water consumed by the chickens did not change, it can be concluded that the additives added to the water in the examined amounts do not have a spicy or unpleasant taste that would cause the birds to refuse to drink water. The relative length of duodenum, jejunum, cecum and colon was not affected by experimental treatments. However, the relative length of the ileum was lower in the chickens that received Entex in the feed compared to the control group. No significant difference was observed in the relative length of different parts of the intestine in the treatments that received herbal additives either in feed or water. The relative length of duodenum, jejunum, cecum, and colon, villus length, villus area, crypt depth, thickness of lamina propria, thickness of muscular layer, and thickness of advantis layer were not affected by experimental treatments. The chickens that consumed 500 mg/kg of Entex herbal additive of feed had a lower villus width in the ileum region compared to the control group chickens. The population of Escherichia coli bacteria in the ileum of chickens that had received the addition of O.X. Plant and Entex in the feed decreased compared to the control group. The population of Escherichia coli bacteria in the Entex treatment in the feed was also reduced compared to the Coxan treatment in the feed. The population of Lactobacillus bacteria in the ileum of chickens that received Coxan in water, O.X. Plant in feed and water, and Entex in feed increased compared to the control group. There was no significant difference in the population of Escherichia coli and Lactobacillus bacteria in the treatments that received herbal additives either in feed or in water. The use of plant essential oils in poultry feed, while improving the microbial population by increasing the number of lactobacilli, by improving the morphological characteristics of the intestine, probably improves the ability of digestion and absorption in the digestive system and improves the growth efficiency of broiler chickens. Antibody levels against SRBC were higher at 28, 35, and 42 days in all chickens consuming herbal additives in water. The performance of animals is significantly influenced by the state of health and safety of the animal. A weak or stressed immune system causes weight loss when dealing with infectious diseases, so the use of immune system stimulating substances can increase performance by improving the immune status. In raising poultry, it is important to strengthen the immune system to prevent the occurrence of diseases.
The results of this research showed that the commercial plant additives of Coxan, O.X. Plant, and Entex had no significant effect on growth performance, relative length and intestinal morphology. The population of opportunistic bacteria Escherichia coli was significantly reduced compared to the control group with the addition of O.X. Plant and Entex in the diet. In general, it can be concluded that adding tested herbal additives not only did not have a negative effect on the drinking water consumption of broiler chickens, but also using them in water improved the immune responses of broilers more than adding them in feed. A total of 336 Ross 308 broilers were examined in a completely randomized design with 7 treatments, 4 replications, and 12 chickens per replication. Experimental treatments included: control (without phytogenic in feed or water), Coxan in feed (300 mg/kg) and in water (200 mL/1000 L), O.X. Plant in feed (200 mg/kg) and in water (135 mL/1000 L) and Entex in feed (500 mg/kg) and water (350 mL/1000 L). Daily weight gain, daily feed intake, daily water intake and feed conversion ratio were measured. At 42 days of age, 2 birds were selected from each experimental unit and after slaughter, the length of the intestinal components was measured separately (duodenum, jejunum, ileum). In order to determine the microbial population, samples were taken from the ileum of chickens. EMB culture medium was used to determine Escherichia coli population and MRS culture medium was used for Lactobacillus bacteria. To check the humoral immune response, 0.1 ml of 25% sheep red blood cell solution in PBS was injected into the breast muscle of chickens on the 12th and 29th days of rearing. Blood was taken from the chickens on the 28th, 35th and 42nd days of breeding and the levels of Anti-SRBC, immunoglobulin G and M were calculated. Antibody titer against Newcastle disease was measured by HI method. The effect of additives in water and feed on average daily feed consumption, daily weight gain, feed conversion ratio and daily water consumption was not significant in the whole period. Since the amount of water consumed by the chickens did not change, it can be concluded that the additives added to the water in the examined amounts do not have a spicy or unpleasant taste that would cause the birds to refuse to drink water. The relative length of duodenum, jejunum, cecum and colon was not affected by experimental treatments. However, the relative length of the ileum was lower in the chickens that received Entex in the feed compared to the control group. No significant difference was observed in the relative length of different parts of the intestine in the treatments that received herbal additives either in feed or water. The relative length of duodenum, jejunum, cecum, and colon, villus length, villus area, crypt depth, thickness of lamina propria, thickness of muscular layer, thickness of advantis layer were not affected by the experimental treatments. The chickens that consumed 500 mg/kg of Entex herbal additive of feed had a lower villus width in the ileum region compared to the control group chickens. The population of Escherichia coli bacteria in the ileum of chickens that had received the addition of O.X. Plant and Entex in the feed decreased compared to the control group. The population of Escherichia coli bacteria in the Entex treatment in the feed was also reduced compared to the Coxan treatment in the feed. The population of Lactobacillus bacteria in the ileum of chickens that received Coxan in water, O.X. Plant in feed and water and Entex in feed increased compared to the control group. There was no significant difference in the population of Escherichia coli and Lactobacillus bacteria in the treatments that received herbal additives either in feed or in water. The use of plant essential oils in poultry feed, while improving the microbial population by increasing the number of lactobacilli, by improving the morphological characteristics of the intestine, probably improves the ability of digestion and absorption in the digestive system and improves the growth efficiency of broiler chickens. Antibody levels against SRBC were higher at 28, 35 and 42 days in all chickens consuming herbal additives in water. The performance of animals is significantly influenced by the state of health and safety of the animal. A weak or stressed immune system causes weight loss when dealing with infectious diseases, so the use of immune system stimulating substances can increase performance by improving the immune status. In raising poultry, it is important to strengthen the immune system to prevent the occurrence of diseases. The results of this research showed that the commercial plant additives Coxan, O.X. Plant and Entex had no significant effect on growth performance, relative length and intestinal morphology. The population of opportunistic bacteria Escherichia coli was significantly reduced compared to the control group with the addition of O.X. Plant and Entex in the diet. In general, it can be concluded that adding tested herbal additives not only does not have a negative effect on the drinking water consumption of broiler chickens, but using them in water improves the immune responses of broilers more than adding them in feed.

Lipids (fat and oil) are the most concentrated sources of energy for animals, which are usually added to poultry diets to meet energy requirements for better performance (Abudabos 2014). However, there are problems with dietary lipid levels and digestibility in poultry, especially in young birds due to low bile secretion (Ravindran et al 2016). This physiological limitation of the poultry digestive system can be solved by using exogenous emulsifiers. Emulsifier can help increase the active level of lipids, stimulate the formation of micelles, and then increase the digestibility of dietary lipids and other nutrients in broilers (Siyal et al 2017). Upadhaya et al (2017) showed that 1, 3-diacylglycerol as an exogenous emulsifier can improve growth performance and increase nutrient digestibility in broilers. In addition, a large number of studies have also shown that exogenous emulsifier can improve meat quality and regulate fat metabolism of broilers (Zhao and Kim 2017). Bile acids are the main pathway of cholesterol catabolism in mammals. Cholesterol is converted into bile acids by changes in ring structure, oxidation and side chain shortening (Li and Chiang 2019). The chemistry of bile acids is complex due to the large variety of chemical structures in natural compounds such as cholic acid, kenodeoxycholic acid, deoxycholic acid, and lithocholic acid. Bile acids of birds are mainly composed of kenodeoxycholic acid and cholic acid (Hoffman and Hagee 2018). Recently, bile acids have been considered as an emulsifier to increase digestibility (Upadhaya et al 2019) and improve the performance of broiler chickens (Parsai et al 2007). Supplementation of bile acids in the diet of broilers significantly improves fat digestibility (Lammasak et al 2019). The effect of bile salts on performance, carcass characteristics and blood parameters of broiler chickens were investaigeted.

Three hundered one-day-old broilers (Ross 308) were divided into 5 treatments and 6 replications with 10 birds in each replication. Five experimental treatments included the control diet (corn soybean based diet), emulsifier (added to control diet) and three levels of 0.05%, 0.1% and 0.2% of poultry bile salts (added to control diet). All the dietary treatment were fed to the birds from day one to day 42 of age. The experiment lasted for 42 days and were performed during the starter (1-10 days), grower (11-24 days) and finisher (25-42 days). Performnce indices were measured during the difeferned periods and carcass characteristics and blood parameters were determined on day 42 of age. The data obtained from the present study were statistically analyzed using SAS statistical software and GLM procedure. To compare the means, Tukey's test was used.

The results showed that consumption of different levels of bile salts had no significant effect on feed consumption (P<0.05). However, consumption of 0.1% bile salts improved body weight gain and feed conversion ratio during the starter period (P<0.05). Previous studies have shown that the consumption of 0.05% commercial emulsifier can improve the growth performance of broiler chickens (Wang et al 2016). In addition, in the present study, 0.05% poultry bile acids supplement significantly improved daily weight gain and feed conversion ratio during 1 to 10 days, which is consistent with the results of Alzawqari et al (2011) regarding bile. These researchers observed improvement in daily weight gain with 0.05% bovine bile acid supplementation. Arshad et al (2020) reported that feed intake was not affected by bile acid supplementation in the initial, growth, finisher and overall periods. In the newly hatched chick, the ability to digest and absorb dietary fat is poor as a result of limited bile secretion (Tancharonrat et al 2013). For this reason, artificial bile acid and bile salts have shown the greatest effect in young broiler chickens to improve fat digestion, and the improvement in the performance of birds receiving bile in the initial period of recent research was for this reason. The results of Maisonnier et al (2016) showed that 0.5% of pig bile acids can increase fat digestibility and body weight in broilers. These results may imply that the supplementation of bile acids in diets improved the growth performance of broiler chickens by increasing the solubility and digestibility of dietary fat and fat-soluble nutrients in this study. Abdominal fat decreased significantly by consumption of 0.1% bile salts (P<0.05). Subcutaneous fat and abdominal fat are considered as the main factors influencing the performance of poultry carcasses (Tůmová and Teimouri 2010). In agreement with our results, many researchers have pointed out the positive effects of emulsifier on reducing fat status and improving carcass quality in broiler chickens (Zhao and Kim 2017). Blood triglyceride concentration was decreased in 0.05% bile salts fed birds wherease cholesterol and uric acid concentrations decreased in the birds fed emulsifier (P<0.05). Triglyceride, cholesterol, HDL and LDL blood are key indicators of lipid metabolism balance (Helkin et al 2017). In agreement with our results, researchers reported that bile acids increased hepatic AST and ALT activity in broilers and reduced serum triglyceride levels, which could be due to the participation of these enzymes in the lipogenesis process (Ge et al 2019). In addition, Siyal et al (2017) showed that feed emulsifier can reduce serum triglyceride concentration in broilers. It can also be stated that bile acids may enhance fat catabolism and inhibit fat synthesis by regulating the expression of genes related to lipid metabolism which may play a pivotal role in improving serum lipid profile and reducing fat deposition in broiler chickens (Ge et al 2019).

Totally, it was found that dietary bile salts supplementation improves the performance of, carcass characteristics and blood lipids in broiler chcikens.

Heat stress is one of the serious issue in poultry industry which causes significant economic losses. Decreasing feed consumption, increasing excretion and decreasing the bioavailability of nutrients during heat stress reduces the performance and immune response. Selenium is an essential trace element for humans and animals that plays a role in improving the antioxidant status and the immune system and inflammatory response. The goal of this study was to investigate the effects of different selenium sources [2-hydroxy-4- methyl seleno butanoic acid, selenomethionine and sodium selenite) on performance, carcass characteristics, antioxidant and immune response and blood characteristics in broiler under heat stress condition.

This experiment was conducted in a completely random designs with 240 Arbor Acres (Male) broilers chicks. Chicks were randomly distributed in 4 treatments and 6 replicates (10 chicks in each replicate). The experimental treatments include that: (1) basal diet + 0.3 mg 2-hydroxy-4- methyl seleno butanoic acid; (2) basal diet + 0.3 mg selenomethionine per kilogram of diet; (3) basal diet + 0.3 mg sodium selenite per kilogram of diet; (4) The basal diet that did not have any additives. The birds were kept at 32-340C (10.00 to 16.00; for 6 hours) from 22 to 42 days.

The results of this experiment showed that feed intake, body weight gains and feed conservation ratio were not affected by the experimental diets. The use of different sources of selenium had no significant effect on blood biochemical factors in broiler chickens under heat stress. dding selenium source with 0.3 mg/kg 2-hydroxy-4- methyl seleno butanoic acid significantly affected immunoglobulin G in comparison to other treatments. Diets containing selenium sources significantly increased the relative weight of the spleen compared to the control treatment (P < 0.05). The treatments of 2-hydroxy-4- methyl seleno butanoic acid and selenomethionine significantly decreased liver weight percent. The concentration of glutathione peroxidase, superoxide dismutase and catalase enzymes in blood were significantly increased by selenium sources in different treatments.

The use of selenium source improved the immune system and blood antioxidant status in broiler chickens.

Silver nanoparticles are one of the new achievements in nanotechnology, which are used in medicine, veterinary medicine, agriculture, and pharmaceuticals due to their antimicrobial activity. Silver nanoparticles can react with biological macromolecules and induce apoptosis by disrupting intracellular homeostasis. Hence, the aim of this study was to the effect of zeolite, organic acid and silver nanoparticles coated on zeolite on the expression of BAX and Bcl2 apoptosis genes in broiler chickens.

The number of 450 one-day- old broiler chicks (Cobb 500) were used in five treatments and six repetitions with 15 chicks per replicate in the form of a completely random design. Experimental diets were: control or basal diet (1), a basal diet supplemented by 1% zeolite (2), a basal diet supplemented by 1% zeolite coated with 0.5% nanosilver (3), a basal diet supplemented by 0.15% organic acid (4) and a basal diet supplemented by 1% zeolite coated with 0.5% nanosilver and 0.15% organic (5). The experiment was conducted with broiler chicken from 1 to 42 days old. The expression of the BCL2 and BAX apoptosis genes, liver sampling was done on the 21st and 42nd days of the breeding period.

The results of this experiment showed that in broiler chicks receiving zeolite treatment (Z) on d 21 and silver nanoparticles coated on zeolite treatment (NS) on d 42 of the breeding period the expression level of Bcl2 gene in liver tissue was significantly increased (P<0.05) compared to the control treatment (C Also, the expression of the BAX gene in the liver tissue in NS and NSOA treatments on d 42 of the breeding period increased significantly compared to the control treatment (P<0.05).

In conclusion, the results of this experiment showed that zeolite and NS and NSOA treatments have an increasing effect on the expression of Bcl2 and BAX genes, while this effect was not observed in organic acid treatment.

This study aimed to compare the relative weight of visceral organs, different carcass cuts, the relative length of different intestinal segments, meat quality, hematocrit, and blood metabolites between Arian and Ross308 broiler strains. 

One-day-old mixed-sex broiler chickens from Ross308 and Arian strains were separately allocated to two treatment groups. The initial number of each broiler strain was 48, divided into 12 replicate cages with four chicks each. On days 32 and 42, one bird per replicate was randomly selected (12 broilers from each treatment group), weighed, and killed by cutting the jugular vein with a sharp knife. Then the relative weights of visceral organs and relative length of small intestine segments were determined for both strains. The carcass characteristics and the breast and thigh meat quality (including water-holding capacity, cooking loss, and lipid peroxidation) were assessed only in the birds killed on the 42nd day of age. Some plasma metabolites and hematocrit were also determined after blood collection into heparinized tubes at the end of the rearing period.

The results showed that the total feed intake of Arian broilers was higher than that of Ross 308 (P≤0.05), but no difference was observed in the feed conversion ratio (FCR) between the two strains. The rate of weight gain in the first two weeks was higher in the Arian strain (P≤0.05). However, this trend was reversed during the 5th week of the rearing period. The carcass and valuable cut yields at 42 days of age were higher in Ross308 broilers compared to Arian birds (P≤0.05). On both days of slaughter, the gizzard relative weight was higher in Arian broilers, while the bursa relative weight was lower in this strain compared to Ross308 (P≤0.05). The visceral fat relative weight showed a significant difference between the two strains only at 42 days of age, and it was higher in the Arian broilers (P≤0.05). There was no strain difference in relative weight of the gut and different segments of small intestine at both examined ages. However, the proportion of the jejunum to the total length of the small intestine in the Arian strain was significantly higher than that of the Ross 308 (P≤0.05). Mean plasma uric acid concentrations were significantly lower in Arian compared to Ross 308 (P≤0.05). However, the mean concentration of plasma total triglycerides and hematocrit values were higher in Arian broilers (P≤0.05). The amount of stimulated malondialdehyde in the breast and thigh meat showed higher values in the Arian broilers (P≤0.05), indicating the lower oxidation stability of the chicken meat of the Arian broilers compared to Ross308.

According to the results of the present study, Arian was not competitive with Ross 308 as a well-known commercial broiler strain in terms of the examined parameters. However, by gaining a better understanding of the weekly performance, carcass characteristics, and blood parameters of the Arian strain at different ages and in comparison with the Ross 308, the broiler farmers will be able to adopt the best management and nutritional strategy for raising these native broilers chickens.

In the poultry industry, the heat stress caused by high environmental temperature has a negative influence on broiler chicken performance and has become a major challenge. Transcriptome profile analysis of the data and identification of patterns of differential gene expression in related tissues can be involved in the discovery of molecular mechanisms resistant to heat stress. The main purpose of this study was to use transcriptome profiles of three tissues brain, liver, and leg muscle of two groups of the control and heat stress broiler chickens to identify candidate genes associated with heat stress. By the analysis of microarray data to express the gene differences, 657 significant genes (P<0.05) were extracted, which a total of 94 genes showed significant expression differences (FDR < 0.05, Fold change > ± 2). Then, by studying the ontology of the relevant genes resulting from data analysis and literature mining as well as the reconstructed protein-protein interaction network, hub genes including NSDHL, DHCR24, LSS, FDPS, PCK1, ACTA1, HSP90AA1, HSPA2, HSPB1, HSF1, CRYAB, APOB, and IL6 were identified. Annotation results of these genes indicated that they have a role in the main process of metabolic and signaling pathways related to the ion transport system, steroid, antibodies, cholesterol biosynthesis, lipid metabolism, immune system function, and various signaling pathways such as MAP kinase, RET, and ERK. Overall, the present study can provide new insights into evidence of the pathways activated by these genes to identify effective genes and a better understanding of biological processes related to heat stress.

Many studies have been conducted to determine proper corn particle sizes for mash or pelleted diets in broiler chicken’s nutrition, aiming not only to achieve optimum production goals such as higher weight gain and minimum feed conversion ratio but also to reduce milling energy expenditures. However, pelleted and crumbled feed forms are mainly used in intensive poultry production systems in many countries, and mash feed is primarily common in less intensive production systems. Mash feed is less costly and puts less pressure on birds’ metabolic systems to achieve their optimum biological growth potential, which may result in higher welfare and lower metabolic disorders. Therefore, the purpose of this study was to investigate the effects of different proportions of fine and coarse ground corn (3- and 6-mm sieve opening hole size, respectively) on performance, the relative weight of gastrointestinal organs (%), and intestinal morphology in male broiler chickens.
A total of 576 1-day-old male Ross 308 broiler chicks were purchased from a commercial hatchery and raised from 1 to 42 days of age. All birds received identical basal diets from 1 to 11 days of age, but different experimental diets from 12 to 42 d. Experimental diets (12 to 42 days of age) consisted of six corn mixtures prepared by combining different proportions (w/w) of corn ground through sieves with either hole sizes of 3 or 6 mm as 100:0; 80:20; 60:40; 40:60; 20:80 and 0:100 percentage, respectively. The particle size characteristics including geometric mean diameter (GMD) and geometric standard deviation (GSD) of ground corn and finished feed samples were determined. Birds’ body weight was recorded at 12, 24, and 42 days of age as a group basis for the calculation of birds’ bodyweight gain (BWG) during the grower (12-24 d) and finisher (25-42d) periods. The birds’ feed intakes (FI) were also measured during the same period to calculate the feed conversion ratio (FCR) after adjustments were made for the body weights of dead birds, which were recorded daily. on the 21st day of the experiment, two birds from each pen were selected and killed via cervical dislocation. The liver, gizzard, small intestine, caecum, and pancreas of the sampled birds were carefully removed from their abdominal cavity, their weights were recorded carefully, and the relative weights of these parts to the live body weights were calculated and expressed as the percentage of birds live weights. Gizzard acidity was measured on the 21st day of the experiment. Parts from the middle of the jejunum and ileum of slaughtered birds (21 d) were excised and flushed gently with saline solution and immediately placed in a 10% formalin solution. Villus height, villus width, and crypt depth were measured in the laboratory.
Results showed that feeding mash diets with different particle sizes (~775, 835, 910, 1000, 1060, and 1150 µm) had no significant effects on birds’ BWG, FI, and FCR during different growth periods. However, the orthogonal polynomial contrast test showed that the changing of feed particle size from fine (~775 µm) to coarser particles by combining different portions of corn ground with a sieve hole size of 3 mm (~775 µm) and 6 mm (~1150 µm) had linearly deteriorated BWG and FCR from 12 to 24 days of age. The birds’ mortality rate (%) was not influenced by average feed particle size from 12 to 42 days of age. The negative influence of very coarse particle size from 12 to 24 days of age (>1000 µm) in the current experiment is an indicator of birds’ gastrointestinal limits in dealing with coarse particles. The coarse grain particles increase the energy required for the growth and maintenance of the gizzard. The results of the current experiment showed that feed particle size did not significantly affect the relative weights of gastrointestinal sections to body weight at 21 d (P>0.05). However, the relative weight of gizzard to live body weight at 21 d significantly (P<0.001) increased in birds fed diets with higher average particle size (≥775 µm). The results of the orthogonal polynomial contrast test showed that the relative weight of gizzard to live body weight at 21 days of age linearly (P<0.0001) increased by changing the feed particle size from fine to coarser particles. Coarse particles increased the digesta content in the gizzard, which stimulates the development of the gizzard. In addition, the findings of the current experiment indicated that ileum and jejunum morphometry traits such as villus height, crypt depth, villus height to crypt depth, villus tips, and base widths were not influenced by changing the average feed particle size. The pH of gizzard content at 21 days of age was not influenced by the feed particle size.
Feed particle size of 775 to 1150 µm in a corn-based mash diet had no significant effect on performance traits or small intestine morphology traits. However, high coarse diets had the potential to deteriorate BWG and FCR at earlier stages of the growth period.

This study was conducted to evaluate antibacterial properties of Optocid acidifier against pathogenic bacteria, growth performance, nutrient digestibility, blood calcium and phosphorus concentrations, and intestinal histology of broiler chickens. In vitro coundition the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of Optocid against pathogenic bacteria of poultry (Salmonella, Escherichia coli and Clostridium perfringens) were evaluated. In vivo stage, a total of 100 one-day-old male Ross-308 broiler chicks were allotted to a complete randomized design with 2 treatments, fed non-supplemented diet and fed diet containing 0.1% Optocid with 5 replications and 10 birds each. The results of MIC and MBC revealed that this product was effective against all three pathogenic bacteria. Dietary Optocid supplementation significantly decrease 10d live weight and daily feed intake in 2-10 day of age period. Dietary Optocid supplementation was not affect on growth performance traits in 11-23 day of age. During the finisher (24-42d) and the whole experimental (2-42d) periods the final live body weight, daily weight gain, feed conversion ratio, European production efficiency factor and economic performance improved as diet supplement by Optocid. Dietary Optocid supplementation increase protein digestibility, and intestinal villi height. It is concluded, dietary Optocid supplementation (0.1%) can be effective on growth performance, health and development of the digestive system in broiler chickens.

During the past decades, rapeseed production, including canola varieties, has surpassed peanut, sunflower, and even cottonseed in production, and ranks second among oilseed crops worldwide. Due to its drought endurance, canola may be the preferable grain for cultivation in several locations of Iran. Canola seed (CS) is an economic feed ingredient containing well-balanced protein (19 to 22%) and a high oil content, up to 45% in some cases. Apart from the oil content of CS, its concentration of dietary fiber, glucosinolates, and tannins are of concern. Canola has less glucosinolates and erucic acid than rapeseed. It, resulting in a higher level of vital nutrients and higher nutrient density. The nutrient composition and presence of anti-nutritional factors in CS may also affect its quality and feeding value for poultry. However, the presence of some glucosinolates, erucic acid, and other undesirable compounds such as phytates, polyphenols, and soluble non-starch polysaccharides (NSPs) may reduce nutrient digestibility and performance of the chickens. Heat process affects the rate of protein denaturation, starch gelatinization, digestive enzymes accessibility, bacterial counts and toxin degradation of feed. On the other hand, starch gelatinization by heat processing may increase amylase effects to break the chains of amylose and amylopectin, which in turn increases the digestibility of less digestible carbohydrates, improves metabolizable energy and digestibility of amino acids in beans, soybeans, peas and canola. Some concerns have been raised about the inclusion levels of CS in broiler diets. This experiment was carried out to investigate the effect of processing method on apparent metabolizable energy (AME), apparent metabolizable energy corrected for nitrogen (AMEn), apparent dry matter digestibility (ADMD), and apparent nutrients digestibility (and) of CS (Nafis variety) in broiler chickens.
This study was designed to determine the nutrient digestibility and, AMEn value of crud and heat processed CS. The CS used in this research was of the Nafis variety, which was sourced from the Astan Quds Razavi farm, Mashhad, Iran. The obtained CS sample was divided to three equal subsamples. One part was unprocessed, second part was micronized; one hour before processing CS was moistened by 20% of the weight, and then placed in a single layer on a vibrating conveyor belt under the infrared emission source at a speed of 6.25 cm/s until the surface temperature of the grain should reach 130○C, and third part super-conditioned under humidity of 16% and temperature of 75-85○C for 3-4 minutes. A total of 48, day-old Ross 308 male broiler chicks was obtained from a commercial hatchery. Chicks were reared and housed in battery brooders in a room. From day one to 10 and 11 to 15, chicks had ad libitum access to conventional corn-soybean meal starter and grower diets, respectively, to meet the nutrient specification of the strain as recommended by Ross 308 manual. A common corn-soybean meal diet was formulated to serve as the reference diet to meet or exceed the nutrient requirements of broiler chicks as described for the Ross 308. The CS samples (row, micronized, and super-conditioning) were incorporated into the reference diet at a 40% inclusion rate (60% reference diet and 40% CS). The digestion trial included a 4-day preliminary period in 16–19d of age, followed by 4 days of recorded total feed consumption and excreta collection. The feed was provided ad libitum during the preliminary and the collection period. During the collection period (20-23d of age) total feed intake was measured, and excreta from each cage were collected twice a day, pooled, and kept frozen at -20oC until subsequent analyses. The excreta samples were oven-dried at 60○C for 72 hours to determine dry matter content. The dried excreta and diet samples were ground through 20 mesh screens, and nutrient content was determined according to (AOAC, 2000). The gross energy of the dried excreta and diet samples was measured with Bomb-calorimeter (Model 1266, PARR). The apparent nutrients digestibility, AME and AMEn of the reference and test diets were determined. Accordingly, apparent nutrients digestibility, AME and AMEn of the CS was calculated as: ”.
The average of dry matter, crude protein, ether extract, fiber, ash, and gross energy for CS were 96.20, 17.70, 46.60, 6.00, 4.11%, and 7137 kcal/kg, respectively. The apparent digestibility of dry matter, crude protein, crude fat and AMEn for raw CS in broiler chickens were 54.28±1.19%, 69.42±1.13%, 77.1±1.32%, and 4673±268 kcal/kg of dry matter. Processing of canola by micronization and super-conditioning method numerically increased the dry matter content of CS by 2.46% and 0.88%, respectively. Crude fat and crude protein content also changed with a similar trend to dry matter content. The effect of canola processing on AME and AMEn in broilers was not significantly (P> 0.05). Micronizing process of CS increased ADMD and AMEn values of 7.47% and 117 kcal/kg than non-processed seed, respectively. Super-conditioning process was less effective than micronization on improving CS nutrient digestibility and AMEn values.
The outcomes of the present study showed that spit non-significant effect of heat processing on energy value and nutrients digestibility of CS (Nafis variety) that might be due to better tolerance of chickens fed recent varieties of CS. However, the change in nutrients digestibility and AMEn values of CS with processing by super- conditioning method was poor, a trend of improving nutrient digestibility and AMEn values were seen in micronize process. More research is needed to clarify the response of the chickens when CS in the raw, micronized or conditioned forms.

Today, livestock and poultry health in an advanced production system is a major challenge affecting human health and the global economy. Antibiotics have been used in poultry nutrition for many years. Chickens are raised with the assistance of the regular use of antibiotics, not only for the prevention and treatment of diseases but, also, for body growth. Overuse and misuse of antibiotics in animals are contributing to the rising threat of antibiotic resistance. In recent years, as a result of increasing concerns about the possibility of developing antibiotic-resistant strains, as well as the fact that they remain in animal tissues and eventually ban their use, the use of compounds such as organic acids, probiotics, prebiotics, enzymes, etc. as safe alternatives have been widely considered in poultry nutrition. Organic acids are a good alternative to antibiotics in poultry diets. These are improving the immune system of broilers by acidifying the gastrointestinal tract and improving the intestinal microflora. Organic acids cross the bacterial membrane; inside the bacterial cell, it produces hydrogen ions and bicarbonate, which eventually increases the acidity. Therefore, they force the bacteria to consume energy in order to keep the acidity constant, which leads to their death. Coating of organic acids prevents its dissociation and digestion in the stomach so that the biological effect of organic acids reaches the distal parts of the gastrointestinal tract and is effective in intestinal microflora and mucosal morphology. This study was performed to investigate the effect of encapsulated organic acids on microbial population, intestinal acidity, blood indices, nutrient digestibility, and viscosity of digestive contents, carcass characteristics and performance of broilers. 150 male broiler chickens of Ross 308 commercial strain as one-day-old were allocated in a completely randomized design with 5 treatments, 3 replications and 10 chickens per replicate. Experimental treatments included: 1. Basal diet 2. Basal diet + commercial Organic acid 3. Basal diet + Non-encapsulated organic acid 4. Basal diet + Encapsulated organic acid 5. Basal diet + encapsulated organic acid + Non-encapsulated organic acid. On day 42 of the experiment, one chickens from each experimental unit, which were close to the weight average of that unit, were selected and blood samples were taken from their wing veins. AT 42d, from each replication, a chick with the same weight as the average weight of the experimental unit was taken and their live weight was recorded and slaughtered. Also, from each replication, a chick with a weight similar to the average weight of the experimental unit was selected and their live weight was recorded and slaughtered. Then, different parts of the carcass were weighed by peeling and emptying the viscera. In order to evaluate the microbial population of the intestines of the tested broilers, at the age of 42 days, one chick from each experimental unit was selected with conditions close to the weight average of the relevant unit and after weighing, it was slaughtered. The microbial population of Lactobacillus and gram-positive and gram-negative bacteria were studied.The data were statistically analyzed by statistical software using GLM procedure. The means were compared by Duncan method at the significance level of 0.05%. The result showed that in growth cycle, weight gain during the growth period and the whole period in the treatments containing encapsulated organic acid showed improvement and a significant difference with the control treatment. The addition of organic acids to the diet during the growth period reduced the conversion coefficient compared to the control group. Feed intake in the treatments containing capsular organic acid showed a significant decrease compare to the control group. The acidity of the duodenum and jejunum showed a significant decrease compared to the control group. The addition of encapsulated organic acids significantly reduced the total number of coliforms in the ileum and duodenum and increased the number of lactobacilli in the ileum. Also, experimental treatments increased the apparent digestibility of crude fat compared to the control group. The weight of the lymph nodes (bursa and spleen) also showed a significant increase under the influence of organic acids. The results of current experimental study showed that the usage of encapsulated organic acids in broiler chicken diets, reduces the acidity of the digestive tract, reduces the intestinal microbial contamination, creates favorable conditions in the digestive system, improves digestibility of the nutrients, and performance of the bird's growing birds.

In order to investigate the effect of inorganic selenium replacement with organic selenium from Spirulina algae on performance and breast meat quality of broilers, a total of 160 one-day-old chicks were used in a completely randomized design with four treatments, eight replicates and five birds per each replicate. The sources of selenium used included sodium selenite and organic selenium from Spirulina algae which were replaced at two levels of 50 and 100 percent. The organic selenium was produced by the culture of Spirulina algae and its enrichment with selenium. The selenium content of different treatments was measured by ICP-Mass method. In this experiment, the feed intake and body weight gain parameters were measured weekly and feed conversion ratio was calculated. At 42 day of age, one bird was slaughtered from each replicate and the weight of carcass ready to cook was measured. The breast meat was sampled for measurement of pH and selenium storage. The results showed that it was not observed any significant difference in performance traits and ready to cook carcass percentage among different treatments. There was no significant difference in breast muscle pH at 0 and 24 hours after slaughtering. The amount of selenium deposited in breast muscle of birds fed organic selenium had significant increase when compared with other treatments (P<0.05). Generally, the results of this study showed that 100% replacement of sodium selenite with organic selenium from Spirulina algae led to increase in breast muscle selenium deposition without reduction in bird performance.

By increasing the poultry and broiler production industry, concerns for  having a food free of pathogens, and as a result, producing a quality and healthy product are increasing. Therefore, correct and efficient disinfection of poultry diets with maintaining the quality of them is very important. The aim of this study was to investigate the effect of gasification of complete poultry feed by ozone on microbial papulation and the quality of broilers diets.

From 432 commercial male Ross strains in a 2 × 2 factorial experiment with three levels of ozone gas (zero, 20 and 30 ppm) and two levels of low fat (1.5 and 2% vegetable oil for growth and finishing periods respectively) and high fat (3 and 4% of vegetable oil for growth and finishing periods, respectively) were used in a completely randomized design with 6 treatments and 4 replications. Diets were ozonated for 120 minutes at concentrations of 20 and 30 ppm. Aflatoxin B1 levels, microbial papulation and the presence of fungi in the feed as well as oxidation of feed lipids in broiler chickens were assayed  after ozonation.

Aflatoxin B1 was not found in grower and finishe diets. The lipid oxidation in ozonated diets with 30 ppm was significantly higher than non-ozonated diets (P<0.05).

According to the results of this experiment, the use of ozone gas to disinfect the broiler chickens diets, despite the destruction and inactivation of microbes and fungi, increases the oxidation of dietary fats.

With the increasing development of broiler industry, increasing feeding costs and concerns, environmental pollution caused by nitrogen and phosphorus disposal, finding ways to increase the bioavailability of nutrients, including phosphorus, is of great interest. The purpose of this experiment was to investigate the effect of the combination of phytase and synbiotic in phosphorus deficient diets on the performance of broiler chickens.

360 one-day-old broiler chickens of Ross 308 strain were used in a completely randomized design with 5 treatments, 4 replications and 18 birds per replication. The birds were fed with the same rations in the first seven days and the experimental diets were given to them from the age of 8 days. Experimental treatments include 1- Control group (diet containing recommended levels of phosphorous), 2- Diet with phosphorus level less than recommended (75% recommended; low phosphorus diet), 3- Low phosphorus diet + phytase, 4- Low phosphorus diet + Synbiotic, 5- Low phosphorus diet + Synbiotic + phytase. Body weight and feed intake were measured in each period and daily weight gain and feed conversion ratio were calculated. At the end of the period, low density serum  cholesterol concentrations, high density poprupe (HDL) and low density poprupe L (LDL) and alanine aminotransferase (ALT) enzymes were measured.

During growth period (24-7 days), the weight gain of birds that received phytase, synbiotic and synbiotic diets with phytase was higher than birds fed control or phosphorus deficient diets and these birds had higher live weight (P<0.05). There was no difference in carcass yield and relative weight of liver and ventricular fat between treatments. Experimental treatments had no effect on serum concentrations of cholesterol, HDL and LDL and alanine aminotransferase (ALT) in broilers. The level of triglyceride in the blood of birds fed phosphorus-deficient diets was lower than that of birds fed control diets containing synbiotics or synbiotics + phytase (p<0.05).

The use of synbiotec + phytase in phosphorus-deficient diets, while reducing the need for phosphorus mineral source, improves the growth performance of broilers and also reduces phosphorus excretion into the environment.

In the recent years, many countries have banned or restricted the usage of antibiotics as growth-promoting, due to their undesirable effects on human and animal health. Using probiotics as an alternative to growth-promoting antibiotics play an important role in improving performance, health and increasing the quality of poultry products. Lactobacilli are the most popular probiotic bacteria that have beneficial effects on host’s performance and health. In this study, the effect of two native strains of Lactobacillus ruteri isolated from the gastrointestinal tract of native chickens in north-western and south-western of Iran were investigated on performance, carcass characteristics, blood parameters and immune response of broilers.

In this experiment, 300 Arbor-Acres® Plus+ male broiler chickens were divided in to 5 treatments, 4 replications (15 chickens per replication), in a completely randomized design. The experimental treatments include: 1- Basic diet as a control treatment, 2- Basic diet + Avilamycin antibiotic, 3- Basic diet + commercial probiotic (Bio-Poul®), 4- Basic diet + Lactobacillus reuteri isolate MG547731 (Plr2), and 5- Basic diet + Lactobacillus reuteri isolate MG547727 (Plr3).

Under the condition of this experiment, commercial probiotics, antibiotic and either Lactobacillus reuteri (Plr2) isolates, significantly improved daily weight gain in final period (p<0.05). Native isolates probiotics and commercial probiotics significantly (p<0.05) reduced the relative weight of gizzard and proventriculus, though no significant (p<0.05) differences were recorded for other carcass components in broiler chickens. After the first injection of SRBC, treatments include antibiotic and Lactobacillus reuteri (Plr2) isolate caused a significant increase of IgM, and after the second injection, Lactobacillus reuteri (Plr2) and commercial probiotic treatments, showed a significant (p<0.05) increase in immunoglobulin G and Total immunoglobulin. The antibody titer against Newcastle vaccine did not show a significant difference between treatments and the control group. There was no significant difference between serum glucose, cholesterol, triglyceride, VLDL and LDL between treatments and the control group. No significant difference was obtained in serum HDL level in probiotic treatments, while antibiotic treatment appeared with a significant decrease in HDL.

Addition of native Lactobacillus reuteri isolates to poultry diets can have beneficial effects similar to commercial probiotics, on performance, immune response and blood parameters of broilers.

 The most important effect of using emulsifiers and l-carnitine in the diet is to help the process of digestion and absorption of fats. Improving the efficiency of metabolizable energy consumption and crude protein when emulsifier and l-carnitine supplements used in the diet indicates the positive effect of emulsifiers on the digestion and absorption of fats and other nutrients. Considering the different metabolic activities l-carnitine and emulsifier (lipidol) in broiler chickens, it seems that the use of these compounds together in low-energy diets can significantly improve the performance of broiler chickens. Therefore, the present research investigated the role of lipidol and l-carnitine supplements in reducing the negative effects of low-energy diets on growth performance, carcass characteristics, nutrient digestibility, blood biochemical parameters and meat oxidative stability of broiler chickens.

The experiment was carried out in a completely randomized design with five treatments in four replicates and 12 chickens in each replicate. Broiler chickens were fed with diets including: 1. control diet 2. Low energy diet (150 kcal/kg less than the control diet) 3. Low energy diet + 100 ppm l-carnitine 4. Low energy diet + 1 g / kg lipidol 5. Low energy diet + 100 ppm l-carnitine + 1 g / kg lipidol for 42 days. Then, the growth performance of chickens, carcass characteristics, blood biochemical indicators (total antioxidant capacity, triglyceride, cholesterol, LDL and HDL concentrations), nutrient digestibility (dry matter, protein, fat and organic matter) in starter and grower periods and meat oxidative stability of broiler chickens were measured and recorded. Finally, the analysis of data was performed using GLM method by SAS software. The means were compared using Tukey's multiple range tests.

The results showed that there was no difference in feed intake between the birds receiving the control diet and the other diets. Weight gain and feed conversion ratio of birds were significantly improved by control diet than other treatments (P<0.05). However, birds receiving low-energy diets containing lipidol + l-carnitine had the same feed conversion ratio (1.79) as birds receiving the control diet (1.75). Birds fed with low-energy diets containing lipidol and lipidol + l-carnitine had better weight gain and feed conversion ratio than birds fed with low-energy diets containing l-carnitine and without additives (P<0.05). Compared to the control treatment, the birds that were fed with low-energy diets containing lipidol and l-carnitine separately and together had a lower abdominal fat percentage (0.4%) (P<0.05). Also, birds fed with the control diet showed a tendency to increase the heart percentage compared to other experimental treatments (P=0.06). Birds fed with low energy diets containing lipidol and lipidol + l-carnitine had higher dry matter (3.6%), protein (7.8%) and fat (6.6%) digestibility in the starter period and higher digestibility of dry matter (6.9%) in the grower period compared to other treatments (P<0.05). In general, in the starter period, the birds fed with control diet showed lower digestibility of protein (P=0.06) and fat (P<0.05), and in the growth period, the digestibility of dry matter was lower than the birds fed with other diets. Birds that were fed with low energy diets containing lipidol and l-carnitine separately or together had higher total antioxidant capacity compared to birds fed with control diet and low energy diet without additives (P<0.05). Also, birds that were fed with low-energy diets containing l-carnitine and lipidol + l-carnitine had lower blood triglyceride (P=0.05) cholesterol and LDL concentrations compared to birds fed with control diet and low-energy diet without additives (P<0.05). Birds fed with low energy diet containing lipidol + l-carnitine increased blood HDL level compared to birds receiving low energy diet without additives (P<0.05). Birds that were fed with low-energy diets containing lipidol and l-carnitine separately and together had lower concentrations of malondialdehyde in thigh and breast meats on days 3, 6 and 9 after slaughter and kept in a refrigerator (4ﹾC) compared to birds fed with low energy diets without additives and control diet (P<0.01). 

Finally, the simultaneous utilization of 100 ppm l-carnitine and 1 g / kg lipidol in low-energy diet showed similar growth performance when compared with control diet and led to improved carcass quality, fat, protein and dry matter digestibility, blood lipid parameters and meat shelf life of broiler chickens.