جستجوی مقالات مرتبط با کلیدواژه « Broiler chickens » در نشریات گروه « علوم دام »

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.

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.

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.

Effect of the type of material used as litter on litter quality and performance and economic parameters of broilers was investigated using 300 day-old Ross-308 broiler chickens by three types of bedding material [date palm leaf (DPL), rice paddy (RP) and cardboard roll (CR)] based on a randomized complete design with three treatments and five replications. The thickness of DPL and RP and CR litters were 3, 3 cm, and the 0.5 mm, respectively. The results showed that water holding capacity of DPL litter was higher than RP and CR litters (P0.05). The ammonia nitrogen content of DPL litter in 28 day was lower than RP and CR litters (P0.05), and this variable in DPL and RP litters in 43 days was significantly higher than CR litter (P0.05). The daily weight gain of broilers in whole period, final live weight and production index in birds raised on DPL litter were higher than RP and CR litters (P0.05). The feed cost and feed conversion ratio of whole period in the birds raised on DPL litter were lower than RP and CR litters (P0.05). The survivality of the birds raised on DPL and RP litters were higher than CR litter (P0.05. In total, the results showed that DPL litter, by improving of performance and economical parameters, can be used an appropriate alternative as broilers litter for RP and CR litters.

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.

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.

 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.

The present research was performed to evaluate the effect of different levels of valine in low protein diets on performance, blood parameters and tibia bone properties of Ross-308 broiler chickens from 8-21 days.

For this purpose, a total of 200 one-day-old male broilers of Ross-308 strain from 8 to 21 days of age in 4 treatments and 5 replications with 10 birds per replication were used. The experimental treatments were adjusted based on nutritional Brazilian Tables (2011) and included: control, recommended level of valine in the diet with 2% diluted crud protein, 10% more than the recommended level of valine in the diet with 2% diluted crud protein and 20% higher than the recommended level of valine in the diet with 2% diluted crud protein. Further performance traits (weight gain, feed intake and feed conversion ratio), biochemical blood parameters (triglycerides, cholesterol, total protein, albumin, superoxide dismutase, glutathione peroxides, urea and uric acid) and bone characteristics (ash, calcium and phosphorus) were measured. Statistical analysis of data in the form of a completely randomized experimental design was analyzed of variance and mean comparison test with SAS software.

The results of the present study showed that the treatment containing 10% more than the recommended level of valine in the diet with 2% diluted crud protein increased the more weight (721.8 g/b) of chickens in growth period (p<0.05). Reduction of dietary crude protein, reduced feed intake (1013.8) during the growing period (p<0.05). Supplementation of 10% more than the recommended level of valine, increased blood superoxide dismutase density (164.8 U/gr Hb). Consumption of 20% more than the recommended level of valine increased blood glutathione peroxides density (172 U/gr Hb) (p<0.05). High dietary protein (control) increased blood urea and uric acid and also increased litter nitrogen (p<0.05). It seems that the addition of valine in low crude protein diets, improved performance and increased blood antioxidant capacity (p<0.05). The 20% more than the recommended level of valine in the diets, increased the calcium density (29.3%) in the bone tibia of broiler chickens (p<0.05).

In generally, according to the results obtained in this experiment, the addition of valine in low protein diets improved performance and increased blood antioxidant capacity and increased calcium and phosphorus absorption in bone.

In most parts of the world, poultry are exposed to mycotoxins-containing foods. Aflatoxins are the most common mycotoxins formed primarily by the fungus Aspergillus. Fungi that produce aflatoxin can grow and multiply on different materials and under different conditions of humidity, temperature and pH (Mohammadi et al., 2015). A variety of additives, including organic acids, plant essential oils and extracts, probiotics, enzymes, vitamins, and minerals, have been tested to alleviate the negative effects of aflatoxins. Medicinal plant extracts contain active natural substances with antifungal and antioxidant properties that are able to reduce the toxicity of aflatoxins in food (Abdulmajeed, 2011). Ferulago angulate is one of the Apiaceae (Umbelliferae) families native to western Iran (Hosseini et al., 2012) that has been shown to have antioxidant properties and to improve the humoral immune system (Govahi et al., 2013). The aim of this experiment was to investigate the comparative effects of hydroalcoholic extract of Ferulago angulate (FAE), antifungal sorbate, probiotic, and vitamin-selenium complex (containing vitamin C, vitamin E, and selenium) on growth performance, immune response and intestinal morphology in broilers chickens challenged with aflatoxins.

A total of 350 one-day-old broilers (Ross 308) were distributed to 7 treatments with 5 replications/treatment in a completely randomized design. The experimental groups were: 1) negative control (NC; basal diet without any feed additive or aflatoxin B1); 2) positive control (PC; basal diet + 0.5 mg aflatoxin B1/kg); 3) PC + 1 g toxin binder/kg (TB); 4) PC + 1 g/kg probiotic PrimaLac (Pro); 5) PC + a vitamin-selenium complex preparation (ECSe; 200 IU vitamin E/kg feed + 250 mg vitamin C/kg feed + 0.2 mg selenium/kg feed); 6) PC + 200 mg/kg FAE (FAE200), and 7) PC + 400 mg/kg FAE (FAE400). Body weight gain and feed intake were recorded during starter (d 1 to 10), grower (d 11 to 24), finisher (d 25 to 42) and whole of the experiment (d 1 to 42), then the FCR was calculated. At the end of the experiment (42 d), 2 birds of each replicate were randomly selected and then slaughtered by Islamic method. Spleen, bursa of Fabricius and thymus weights were measured and relative weight to total BW of broiler chickens were determined. At 42 d of age, blood samples were collected from two birds in each replicate into vials containing EDTA to avoid blood clot formation. The values of hemoglobin (Hb) and hematocrit (Hct), red blood cell (RBC), white blood cell (WBC), as well as blood leucocyte profiles were measured. In order to assay the primary and secondary antibody responses against sheep red blood cell (SRBC), at 28 and 35 d of age, two birds per replicate were immunized intramuscularly with 1 ml of 2.5 % SRBC in PBS. Blood samples (1.5 mL/bird) were obtained from brachial vein at 7 d after each injection (d 35 and 42). For histopathological examination, the jejunal tissues of slaughtered broiler chickens (1 per replicate) were fixed in 10% of neutral buffered formalin, routinely embedded in paraffin, cut into 6-μm thick sections, and processed for hematoxylin and eosin staining.

The results showed that aflatoxin challenge adversely affected growth parameters; while treatments antifungal and FAE200 during the growing period and all additive-containing treatments during the finisher and whole experimental periods reduced the negative effect of aflatoxin on growth performance (P<0.05). The heterophil count and the heterophil to lymphocyts ratio were decreased by all dietary treatments than those determined in the PC group (P<0.05). All treatments, except probiotic, increased the values of red blood cells, white blood cells, and hematocrit as compared with PC group (P<0.05). The antifungal, probiotic and FAE400 treatments also increased the secondary IgG titer against sheep red blood cells in the aflatoxin-challenged birds (P<0.05). Furthermore, vitamin-selenium and FAE-containing treatments alliviated the negative effect of aflatoxin on villus surface area (P<0.05). According to a previous study (Hussein, 2015), the weight loss during aflatoxin challenge have been attributed to the toxic effects of mycotoxins on different cell organs, resulting in chickens refusing to consume toxins in their diets. It has been documented that the use of additives like selenium is used to remove fungi such as Aspergillus in poultry feed (Hatfield et al., 2012), which can explain the reduction of negative effects of aflatoxin on performance by vitamin-selenium mixture treatment in the present study. It is also reported that lipid peroxidation and the production of free radicals can cause damage to cell membranes during aflatoxicosis (Manafi and Khosravinia, 2013). Therefore, due to their antioxidant properties, vitamin C, vitamin E, and medicinal plants can prevent the production of free radicals in biological systems and thereby improve performance and health status under aflatoxin-inducing conditions. The phenolic compounds, especially polyphenolic compounds in the FAE have been reported to have a high ability to scavenge free radicals and thus can be used as a natural antioxidant in food and pharmaceutical industry (Hosseini et al., 2012). As a result, consuming FAE might reduce the impact of aflatoxin on growth performance, immune response and gut morphology, which is likely due to the antioxidant properties of this medicinal plant and its ability to scavenge free radicals caused by aflatoxin consumption.

In general, according to the findings of this study, Ferulago angulate extract, particularly at a dose of 400 mg/kg of diet, can improve growth performance, immune response, and health status during aflatoxin exposure, which appeared to be comparable to those recorded in the prebiotic and vitamin-selenium treatments. However, the growth benefits by Ferulago angulate extract were poorer than those recorded in the chickens fed with the NC and antifungal diets.

Stress, as a response to adverse stimuli, is difficult to define and understand mostly due to its nebulous perception. As Selye (1976) pointed out, “stress is the nonspecific response of the body to meet any demand”, whereas stressor is defined as “an agent that produces stress at any time”. Hence, stress represents the reaction of the animal organism (i.e., a biological response) to stimuli that disturb its normal physiological equilibrium or homeostasis. Thanks to their antioxidants, nutrients and anti-inflammatory properties silver nanoparticles are used in many developed countries (Bhanja et al 2015). The list potential applications of nanotechnology are very wide and diverse, but it is undoubtedly one of its most valuable applications in the development of therapeutic and pharmaceutical cases. Also, the use of silver nanoparticles in the treatment of deadly diseases like avian influenza supports further research on biological systems (Xiang et al 2011). Among inorganic materials, metal oxides such as TiO2, ZnO, MgO CaO, and Ag are of particular interest because they are stable in hard conditions and generally considered to be safe substances for humans and animals.

A total number of 592 eggs with an average weight of 50 g were purchased from a commercial Hubbard F15 broiler breeder flock aged 50 wk. The eggs, allotted to 4 treatments of 4 replicates with 37 eggs each, were set on the same floor to provide similar incubation conditions. Treatments including 2 doses of silver nanoparticles (20 and 40 mg) was injected via the egg holes using 1 mL insulin syringes equipped with disposable needles (21 gauge). The control group did not receive any treatment, and the sham control was injected with 1 ml phosphate-buffered saline (Triplett et al 2018). The injection holes were immediately covered using paraffin. At the end of d 18 of incubation, the eggs were transferred to the hatching cabinet. On the 21d of incubation, the hatched chicks were taken out of the incubator and after counting (checking for hatching) and weighting, half of the chicks were killed on the same day to check Hemoral immunity (G and M),white blood cell count and study of the desired genes (TNF-α, IL-6 and TGF-β). Among other chickens, those that were more uniform in weight with the desired treatment were transferred to the breeding period for 42 day and again in 4 treatments (treatments applied during incubation) and 4 replications with 20 broilers per replication. During 42 day, broilers were provided with unlimited water and food. To induce oxidative stress during the breeding period, 500 μg/kg live weight Salmonella lipopolysaccharide injected at 12, 24 and 48 hours before killed (Xi et al 2000).

While ovo injection, silver nanoparticles was significantly decreased hatchability in comparison to the control group (P<0/05). In line with our results (Goel et al 2017) found that the hatchability of the eggs injected with nanoparticles was significantly lower than the control group. The reason can be attributed to the smaller size of younger embryos at the 7th ED, injection method, location injection, injection depth, injection time, genetics, hen age, egg size and hatching conditions (Sun et al 2018; Pilarski et al 2005). In case of ovo injection of 20 and 40 mg silver nanoparticles, significantly increased carcass percentage compared to the control group at hatching and post-hatch period, respectively (P<0/05). (Bhanja et al 2015; Pineda et al 2012) proved that silver nanoparticles had positive effects on embryo weight. Due to the significant amount of antioxidant in the silver nanoparticles inside the egg and its antioxidant effect on energy efficiency during embryonic life, silver nanoparticles receiving groups had a higher body weight at hatching time. Higher birth weight makes it possible to increase feed intake and weight gain in these treatments.Upon ovo administration of 20 mg silver nanoparticles, spleen was increased significantly compared to the control group at hatching period (P<0/05). This is in line with a previous study of Goal et al (2017), who observed higher liver and spleen weights in 40 mg/kg silver nanoparticles group. The development of B and T lymphocytes initiates during embryogenesis in the bursa of Fabricius and thymus, respectively, and matures in the spleen until post-hatch (Erf 1997). These organs play an important role in imparting immunity. The cells produced in these organs differentiate into cellular immunity and humoral immunity, thus imparting immunity against different pathogens. Therefore, increased liver and spleen weight indicates a better immunological health status of in ovo silver nanoparticles supplemented birds. Ovo treatments did not affect the concentrations of immunoglobulin (IgG), (IgM), WBC counts and H/L ratio (P>0/05). Our results are consistent with previous studies of Pineda et al (2012) who showed the concentration of IgG and IgM were not affected by ovo injection of 10 and 20mg/kg silver nanoparticles. (Salari et al 2016; Saki and Salari 2015) showed silver nanoparticles increased in serum IgM and IgE, and increased in blood neutrophilic granulocytes. Rezaei Zarchi et al (2012) reported, feeding the rats for 28 days at doses of 25, 50, 100 and 200 mg / kg of silver nanoparticles had no significant effect on WBC and H/L. Differences in results may be due to differences in injection method, location injection, injection depth, injection time, genetics, hen age, egg size and hatching conditions. In comparison with the control and 40 mg silver nanoparticles group at hatching, there was significant up-regulation of TNF-α, IL-6 and TGF-β gene expression in 20 mg silver nanoparticles injected embryos,. Tumor necrosis factor-α (TNF-α) is a key cytokine involved in inflammation and immunity and the pro-inflammatory cytokine IL-6 induces the final maturation of B cells into antibody-secreting plasma cells, thereby increasing the secretion of immunoglobulins (Balkwill 2009; Mosmann 1989). Silver nanoparticles can interact with the immune system by binding and reacting with cells or proteins, thereby modulating the immune response. In the present study, higher expression of TNF-α gene in the livers was observed in ovo injected silver nanoparticles embryos. These findings also support earlier studies by Khan et al (2013), who showed the gene expression of IL-6 and TNF-𝛼 were affected by 50nm GNPs in the kidneys of rats. Also Vadalasetty et al (2018) reported that expression of TNF-α and NF-kB at mRNA were significantly up-regulated in the 50ppm silver nanoparticles group.

The results of this study suggest that silver nanoparticles improve the immune response of broilers by improving growth and increasing the relative expression of genes involved in immune function.

There are different methods to formulate poultry diets, which is one of the newest methods, based on digestible amino acids. Meals are used to provide protein and amino acids in diets. The use of soybean meal has many limitations compared to canola meal. The use of multi-enzyme was done to reduce the limitation in flour such as canola. This experiment was conducted to evaluate the effects of diets formulated based on total and digestible amino acids, soybean and canola meals with or without adding multienzyme on the performance and carcass traits of broilers.

Experiment was conducted as 2×2×2 factorial arrangement with 800 day old of Ross-308 broilers with 8 treatments, 4 replicates and 25 chicks in each,  in a complected randomized design in 3 experimental periods (starter 1-10 days, grower 11-25 days and finisher 25-42 days).

The final results showed that diets formulated based on digestable amino acids, canola meal and enzyme by reduceing the amount of feed intake, improved chicks performance (p<0.05). Canola meal increased the abdominal fat, gizzard, liver and spleen percentages, however the percentages of breast and thighs increased this results also were abserverd in interaction between canola meal, digestible amino acids and enzyme.

The overall results indicated that in broilers in the prsense of multienzyme, use of canola meal in contrast with soybean meal in diets formulated based on digestible amino acids can improve their performance and carcass traits.

The ideal performance of poultry is achieved by adequately feeding of birds while reducing dietary costs and nutrients excretion. On the other hand, the amount of dietary nutrients can have a significant effect on feed intake (Kidd et al., 2002). Studies have shown that reduced growth and yield due to decreased dietary protein can be compensated by supplementing the synthetic amino acids (Hussein et al., 2001). Diets based on total and digestible amino acids can improve the performance (Rostagno et al, 1995). Some properties of valine and tryptophan in relation to non-protein function and metabolism distinguish them from other amino acids. Valine is the fourth limited amino acid to the growth of broilers. Tryptophan involved in all proteins structure and is a precursor for serotonin and melatonin, which in addition to improving food intake (Silber and Schmitt, 2010). Valine affects the ghrelin and neuropeptide Y production (Coto et al, 2006) while tryptophan affects the serotonin secretion (Henry, 1985) that both affects the feed intake. The functions of the two amino acids can improve the performance and immune system of birds.

The current experiment was performed to evaluate the effects of different levels of valine and tryptophan amino acids in low-protein diets on carcass characteristics and immune response of broiler chickens. A total of 450 day-old Ross 308 broiler chickens were randomly divided into nine treatment groups. The chickens were arranged in a 3×3 factorial experiment based a completely randomized design including 3 levels of valine and three levels tryptophan. Each treatment considered of five replicates and 10 chickens per experimental unit. The birds were reared on the litter pen for 21 days with ad-libitum access to feed and water. Diets were formulated based on linear programming by using of the UFFDA software. Experimental treatments were adjusted based on Brazilian tables and included: 1- recommended level of valine + recommended level of tryptophan, 2- recommended level of valine + 5% more than recommended tryptophan, 3-recommended valine level + 10% more than recommended tryptophan, 4-10% more than recommended valine level + recommended level of tryptophan, 5-10% more than recommended valine + 5% more than recommended tryptophan, 6- 10% more than recommended tryptophan level + 10% more than recommended tryptophan, 7- 20% more than recommended valine level + recommended level of tryptophan, 8- 20% more than recommended valine + 5% more than recommended tryptophan, 9-20% more than recommended valine level+ 10% more than recommended tryptophan. On day 21 of experiment, two birds per pen were randomly selected and slaughtered for whole carcass analysis after 12 hours of fasting. After slaughter, the organs such as breast, thigh, abdominal fat, gizzard, liver, heart, spleen, thymus and burs fabricius were weighed. In order to determination of white blood cells, blood sampling drawn from the wing vein at 21 days of age and the number of lymphocytes, heterophils, monocytes, basophils and eosinophils were determined. Blood samples were taken at 21 days of age as well to determination of the antibody titer of Newcastle virus. To measure the immune response to sheep erythrocytes, 2 ml of blood was taken from the chicken vein on 14 and 21 days of the experiment and used to determination of total immunoglobulin and IgM and IgG titers. The antibody titers were performed by direct hemagglutination (Isaco et al. 2005). The CBH test was used to evaluate the cellular immunity. The experiment was conducted using completely randomized design with factorial structure. Data were subjected to ANOVA using the GLM procedure (SAS, version 9.1) as a 3×3 factorial. Significant means among the variables were separated by Duncan's multiple range tests at 5% level of significance.

The results of current experiment showed that the addition of valine and tryptophan in low protein diets had no significant effect on carcass yield, thigh, gizzard, heart and abdominal fat (p<0.05). The consumption of 20% and 10% levels of valine significantly increased the breast weight as compared to the recommended level (p<0.05). No interaction effects was observed between the valine and tryptophan amino acids for the weights of carcass parts and internal organs (p>0.05). In a study, consumption of 10 and 20% tryptophan levels had no significant effect on breast and thigh of broilers at 22 days of age (Duarte et al, 2013). Moreover, addition of valine to poultry diets did not have a significant effect on abdominal fat weight (Corzo et al, 2004). Different levels of valine and tryptophan had no affected the liver and spleen weight (p<0.05). Furthermore, addition of 20% valine caused an increase in thymus and bursa weights (p<0.05). The diets containing tryptophan had a significant effect on the number of blood lymphocytes, so that the addition of 10% tryptophan increased the blood lymphocytes (p<0.05). Valine and tryptophan addition did not affected the other blood leukocytes (p<0.05). Addition of 20% valine increased the humoral immunity (HI antibody titer) (p<0.05). Also, addition of 10% tryptophan level increased the immunity of chickens against HI antibody (p<0.05). The results showed that the initial response of total antibody was not affected by experimental treatments (p<0.05) but 10% level of valine significantly increased the IgM (p<0.05). Dietary addition of 20% valine had a significant effect on IgM secondary response SRBC (p<0.05) but had no significant effect on the PHA-P injection response (p<0.05). It has been reported that protein deficiency have caused the unsuitable growth of lymphoid organs (Corzo et al., 2007).

The result of current experiment showed that consumption of high valine and tryptophan levels in low-protein diets improved the carcass characteristics and immune system of broilers.

The effects of valine supplementation on performance, immunity and behavioural indices of broiler chickens under heat stress condition was evaluated. Total of 420 male and female Ross-308 broiler chickens were allocated to 6 treatments with 5 replicates in a completely randomized design. Experimental groups were as fallows: positive control (fed basal diet and reared under Ross-308 recommended rearing temperature), nagative control (fed basal diet and reared under heat stress (HS)), and four treatment groups fed basal diet supplemented with 5, 10, 15 and 20% valine above the Ross-308 valine recommendation and reared under HS. Heat stress significantly decreased feed intake, body weight and European production efficiency factor (EPEF), antibody titer against NewCastle, lymphocyte percentage, serum total protein concentration and alkaline phosphatase and lactate dehydrogenase activities and increased heterophile percentage, heterophile to lymphocyte ratio, rectal temperature and tunic immobility of broiler chickens (P< 0.05). Supplementation  of5% valine improved BW of broiler chicken at the end of grower and BW and EPEF at the end of total period. Addition of  10% valine increased relative weight of breast and thigh muscle and 15 and 20% valine supplementation increased lymphocyte and decreased heterophile percentage as compared to control group (P< 0.05). In conclusion, 5% valine supplementation improved final body weight and feed convertion ratio of heat-stressed broiler chikens and 15 and 20% valin inclusion improved blood immune cell percentages but had no effect on humoral immune response and tunic immobility test of HS broiler chickens.

Ross and Cobb are two strains of broiler chickens that desirable Conversion Ratio makes them the most appropriate broiler chickens. In this experiment to evaluate morphometric carcass characteristics (live weight, featherless carcass weight, breast weight, thigh weight, back + neck, wing, liver, heart, bursa, spleen, pancreas, proventriculus + gizzard, abdominal fat) sampling of 134 broiler chickens were taken in South Khorasan. The results showed that 12 characteristics (live weight, featherless carcass weight, breast weight, thigh weight, back + neck, wing, heart, bursa, spleen, pancreas, proventriculus + gizzard, abdominal fat) between strains (P<0.01) were significantly different. The liver weight was not significantly different. Edible organs weight mean indicated that meat production efficiency and utility in Ross strain is higher compared to Cobb strain.