جستجوی مقالات مرتبط با کلیدواژه « ال-کارنیتین » در نشریات گروه « علوم دام »

Inovo feeding the nutrients into the egg can reduce the limitation of nutrients inside the egg and hence improve the embryo quality and chick growth. Therefore, a lot of attention should be paid to the growth and development of the embryo in order to access the maximum performance after hatch. Furthermore, providing nutrients to the embryo (embryo nutrition) may be used to improve growth performance and also overcome the development limitations in the late embryonic period and early life of the chick. Providing some nutrients during the incubation period can improve the metabolism in chick embryos and have beneficial effects on performance after hatching period. L-carnitine is a dipolar compound which is soluble in water and it’s in ovo injection may have beneficial effects for chickens because of the limited capacity of young chickens to synthesize L-carnitine. Betaine is a derivative of amino acids (Trimethylglycine) and is classified as a methyl group donor and its beneficial effects on performance of the different birds have been reported in many studies. Therefore, this study was carried out to investigate the effects of inovo feeding of L-carnitine and betaine alone or together on hatchability, carcass traits (drumstick, breast, liver and egg yolk), blood indices (cholesterol, triglycerides and total protein) and expression of some growth associated genes (liver IGF-1 and muscle MyoD and MyF5) and development in chicks.

A total of 630 fertile eggs (Ross 308 strain form 34-wk-old breeder flock) were assigned randomly to six treatments with five replicates and 21 eggs per replicate. The mean weight of the eggs was 56.64 ± 1.18. Treatments included control group (non-injected), dry punch, physiological saline injection (100 µL), in ovo injection of L-carnitine (8 mg), in ovo injection of betaine (2.5 mg) and in ovo injection of both L-carnitine and betaine (8 mg L-carnitine + 2.5 mg betaine). Treatment solutions were injected into the amniotic sac on day 14 of incubation. 100 µL of injection solution was injected with an insulin syringe in the upper third of the egg with an injection depth of 19 mm. During the injection, the temperature of the injection solution was 30°C and environment temperature was 35°C which was performed in 15 minutes for each treatment. After the injection, the injection site was blocked. The eggs were placed in the incubator (37.5 C and 61% humidity). Infertile eggs and the eggs with a dead embryo were also transferred to the laboratory for examination of embryonic mortality. After hatching, the chicks were weighed with a digital scale and an accuracy of 0.01 g and the weight after hatch was determined. Then, two chicks per each replicate were selected and slaughtered to study the carcass traits (drumstick, breast, liver and egg yolk). Blood was taken from neck to determine the blood parameters (cholesterol, triglycerides and total protein). Then the liver and breast muscle of the slaughtered one day old chicks were taken to determine the relative genes expression. Relative gene expressions were measured by Real-Time PCR using gene specific primers. The data obtained from the gene expression were analyzed by the Livak method. The remaining chickens were reared for seven days and weight gain, feed consumption and feed conversion ratio were determined. Data were analyzed using the general Linear Model procedures of SAS 9.1.

The results of this study showed that in ovo injection of 8 mg L-carnitine decreased the mortality and increased the hatchability (P<0.05). Injection of 2.5 mg betaine increased the mortality of embryos during the final stage of incubation and decreased the percentage of hatched chicks (P<0.05). Injection of L-carnitine and betaine alone and in combination decreased the blood triglyceride and cholesterol concentration in serum (P<0.05), while it had no effect on total protein concentration in blood (P>0.05). In ovo injection of L-carnitine and betaine alone or in combination increased the percentage of breast and thigh newly hatched chicks (P<0.05). Injection of L-carnitine and betaine had no effect on the weights of yolk sac and liver (P>0.05). Injection of L-carnitine and betaine and their combination had no effect on the functional characteristics of chickens at 7 days of age (P>0.05). Furthermore, L-carnitine and betaine alone or in combination increased the relative expression of IGF-1 gene in liver and MyoD and MyF5 genes in breast muscle of hatched chicks (P<0.05).

The results of this research showed that L-carnitine may reduce the mortality of embryos in the incubation stage by reducing oxidative stress and thus increases the hatching rate.Totally, the results of current experiment indicated that in ovo injection of L-carnitine and betaine can stimulate the secretion of IGF-1 and consequently increase the expression of muscle regulatory genes (MyoD, MyF5) and hence improved the proliferation and maturation of satellite cells in the embryonic stage. Therefore, L-carnitine and betaine can be recognized as a positive stimulus of IGF-1 signaling pathway in order to stimulate muscle growth and chicken growth.

The Japanese quail is a species known for its short production period and high productivity. Due to their small size and low feed requirements, they are considered a cost-effective option for egg production compared to other poultry species. Additionally, quail eggs are recognized for their superior nutritional value compared to regular chicken eggs. However, there is a need for effective methods to enhance productivity, especially in stressful situations. Previous research has indicated that the use of certain dietary supplements can address this issue and improve the productive traits of birds. Therefore, there is considerable scientific interest in studying the effects of natural compounds such as black seed and L-carnitine on the productive performance of laying Japanese quails, both under normal conditions and during heat stress. Investigating these factors can provide valuable insights into the development of strategies to effectively manage and optimize egg production in laying Japanese quails. This, in turn, would contribute to the sustainability and profitability of the poultry industry. In this study, we aimed to examine the effects of black seed, L-carnitine, and vitamin E on the productive performance, carcass characteristics, blood biochemical parameters, and immune responses of Japanese laying quails.

A total of 500 Japanese laying quails were included in this study. They were divided into two temperature conditions: normal temperature and high temperature (36 degrees Celsius for 6 hours per day). Additionally, there were five experimental treatments: control diet (without any additives), black seed (1.5% black seed diet), L-carnitine (250 ppm + control diet), 1.5% black seed + 250 ppm L-carnitine diet, and Vitamin E diet (200 ppm + control diet). This resulted in a 5x2 factorial experiment with a total of 10 treatments, 5 replications, and 10 quails per replication. The study consisted of three phases: an adaptation period to the experimental diets lasting two weeks, exposure to the designated temperature conditions for five weeks, and a three-week recovery period. During these phases, various parameters were measured and recorded, including productive performance, carcass characteristics, and blood biochemical and immune indicators (such as triglyceride, cholesterol, LDL, HDL concentrations, heterophil, and lymphocyte percentages) under both heat stress and recovery periods in Japanese laying quails. Data analysis was performed using the Generalized Linear Model (GLM) method with the assistance of SAS software. Mean comparisons were conducted using Tukey's multiple range tests.

The results of this study revealed several important findings. During the initial two weeks of the experiment, the consumption of feed containing black seed + L-carnitine led to the highest feed intake, while diets containing black seed, black seed + L-carnitine, and vitamin E demonstrated the highest egg mass compared to the control group (P<0.05). During the heat stress period, high temperatures caused a decrease in feed intake, egg weight, egg production, and egg mass. However, the consumption of feed containing black seed + L-carnitine resulted in increased feed intake, and diets containing black seed, black seed + L-carnitine, and vitamin E showed increased egg production and mass compared to the control group. Furthermore, vitamin E exhibited a better conversion coefficient (P<0.05). During the recovery period, high temperatures led to a decrease in feed intake but an increase in bird body weight. The control group exhibited the lowest feed intake and body weight, whereas diets containing black seed, black seed + L-carnitine, and vitamin E demonstrated the highest egg production and egg mass compared to the control group. Birds fed diets with black seed and vitamin E exhibited a better conversion coefficient (P<0.05). Regarding carcass yield and relative liver weight, the effect of environmental temperature and experimental treatments during both heat stress and recovery periods was not significant. However, the consumption of black seed, L-carnitine, and vitamin E was found to increase carcass yield and relative heart weight. Additionally, high temperatures increased the relative liver weight (P<0.05). Moreover, birds fed control and black seed diets at normal and high temperatures exhibited higher blood cholesterol levels compared to other experimental treatments. In normal temperature conditions and diets containing vitamin E and L-carnitine, a higher percentage of lymphocytes was observed in the blood. In high temperature conditions and diets containing L-carnitine and vitamin E, the heterophil to lymphocyte ratio was also higher (P<0.05).

Finally, the findings of this study highlight the beneficial effects of incorporating black seed, L-carnitine, and vitamin E into the diet of Japanese laying quails, both under normal and high-temperature conditions. These dietary interventions have shown positive impacts on the performance of the quails. Consequently, these results can serve as valuable guidance for quail breeders and producers in selecting suitable feed regimens to manage heat stress in Japanese quail layers, thereby enhancing performance efficiency, carcass characteristics, and blood lipid and immune parameters.

 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.

 Rooster’s reproductive performance is an indispensable component of breeder production because it plays a vital role in the maximum production of fertilized eggs. Existence feed supplement in the poultry industry, intermediary metabolites have been including in the diet to improve fertility and reproductive outcomes. Carnitine (β-hydroxy-γ-trimethylaminobutyrate), vitamin-like-amino acid, is a quaternary ammonium compound, that has multifunctional roles in reproduction. High concentrations of L-carnitine (LC) are present in epididymal lumen, where it participates in sperm energy balance and the maturation of spermatozoa. In light of previously reported breeder birds supplemented with dietary LC have shown improvements in semen traits and fertility parameters. The present study is an attempt to investigate the effects of several levels of dietary LC supplementation on semen quality parameters and gonadosomatic and hepatosomatic indexes at maturity and production peak.

For the present experiment, thirty-six Ross (12-week-old) breeder broilers were used for 22 weeks in a completely randomized design with three treatments (0, 250 and 500 mg L-carnitine in kg of diet) and twelve replications. All roosters were fed standard isocaloric (2754 kcal/kg) and isonitrogenous diet (12 % protein). The birds for 22 weeks in a completely randomized design with three treatments (0, 250 and 500 mg / kg of LC in the diet) and six replications were used. During the adaptation period (21-24 weeks of age), the roosters were trained by abdominal massage for semen collection. After the experimental period was commenced (24 weeks of age), semen samples were collected and evaluated for seminal attributes every two weeks (from week 24 to week 34). The following parameters were determined immediately after the semen collection; to measure the semen samples were collected weekly to evaluate semen volume, total motility, membrane functionality, mitochondria activity parameters. Also, to determine gonadosomatic and hepatosomatic indexes at 24 and 34 weeks of age, six birds in each treatment weighing then were slaughtered and immediately the testes and liver were removed and weighed.

The highest sperm motility (96.60%) was observed in birds fed 250 mg LC (P <0.04). By increasing the level of LC in the diet, sperm membrane functionality improved linearly (6.8% increase compared to control) (P <0.04). A linear trend (P = 0.06) was observed in mitochondrial activity with increasing levels of LC in the diet (69.31, 72.00 and 76.25). LC plays an essential role in energy metabolism by carrying over fatty acids in the mitochondria matrix for β-oxidation producing energy. Therefore, it provides a better supply of energy for spermatogenesis and normal physiology of sperm, are presumably improved by an optimum level of LC, as a result, sperm concentration and live. These data provide evidence that LC can be effectively used in diets up to 500 mg/kg of diet or 30 mg/kg of body weight /day for semen improvements of rooster’s breeder. At 24 weeks of age, the changes in gonadosomatic index (0.55, 0.68 and 0.64) were affected by different levels of LC (P <0.01). During testis development in the chicken (from 2 to 15 weeks of age), there is no significant increase in testicular weight, however, the early stage is the most important period for testicular development. The mature testis has seminiferous tubules with a multilayered epithelium representing the different stages of spermatogenesis. Sexual maturity is associated with the highest testes weight and consequently with the highest plasma concentration of reproductive hormones. Gonads of the mature male broiler breeder are organized into separate, comfortably discernible cellular correlations and functional compartments. It has been accepted that steroid hormones biosynthesis and generation of spermatozoa are two major actions that the testicles fundamentally carry out. The improvements in gonadosomatic Index of roosters observed in this study in response to dietary LC may be attributed, at least partly, due to improved utilization of dietary nitrogen, achieved through more efficient fat oxidation by LC. Testicles contain the seminiferous tubules and the interstitial space. Seminiferous tubules are the functional elements of the testis and sertoli cells are the principal structural basis of the seminiferous epithelium, inhabiting on the substratum membrane.

The addition of 250 and 500 mg of L-carnitine to the diet due to the increase in gonad index led to an improvement in sperm quality parameters at the beginning of the production period (puberty).

L-Carnitine (β-hydroxy-γ-trimethylaminobutyric) is produced in living organisms through food and the biosynthesis of the amino acids lysine and methionine in the liver, kidney, skeletal muscle and brain and then enters the bloodstream. One of the most important functions of L-carnitine in the body is to produce energy, facilitate the entry of long chain fatty acids into the mitochondria, facilitate the exit of short and medium chain fatty acids into the mitochondria, eliminate the toxic effects of acyl groups in cells, regulate the ratio of coenzyme-A versus acyl coenzyme-A in the cytosol and mitochondria. L-carnitine is a plasma lipid-lowering drug that lowers cholesterol, triglycerides, free fatty acids, phospholipids and low-density lipoproteins, while increases high-density lipoproteins. Supplementation of poultry diets with L-carnitine in has been reported to be effective in controlling blood lipids, abdominal fat pad and poultry health. This study aims to investigate the effects of L-carnitine on growth performance, carcass characteristics, abdominal fat, blood biochemical parameters, immune system, cecal microflora, histology of jejenum, taste properties of breast meat and fatty acid composition of breast meat of broilers.

The experiment was performed in a completely randomized design with 3 treatments, 4 replicates, with 10 broiler chicks with the approximate weights of 45±2g in each pen having the dimension of 1.5×1.5m2 and a total number of 120 chicks during 42 days. The experimental treatments included 3 levels of L-carnitine (0, 200 and 400 mg/kg) in corn-soybean meal basal diet. The effects of experimental treatments were analyzed by SAS software and the comparison of the means with Duncan’s multiple-range test at 5% significance level. Body weight gain, feed intake, and feed conversion ratio (FCR) were calculated at the end of feeding phases to evaluate the traits. European Production Efficiency Factor (Aviagen 2018), carcass characteristics (Farrokhyan et al. 2014), blood parameters (Hosseinitabar et al. 2015), immune system (Seidavi et al. 2014), breast meat fatty acid (Folch et al. 1957) cecal microbial population, histology of the small intestine were calculated at the end of experiment (42 days).

In the finisher period of the experiment, the chickens fed by a diet containing 400 mg/kg L-carnitine significantly had lower feed intake and FCR as well as the highest weight gain compared to the control (p < 0.05) ). The reason for the increase in weight of the chickens fed by L-carnitine may be due to the effect of this substance on increasing the insulin-like growth factor-I and also the elevated access of chickens to the energy of feed (Kita et al. 2002). Rabie and Szilagyi (1998) reported that the effect of L-carnitine on improving FCR is related to improving nitrogen metabolism. Elevated levels of L-carnitine significantly increased the European Production Efficiency Factor (P <0.05) in which the highest European Production Efficiency Factor (312.75) was obtained by consuming 400 mg/kg of L-carnitine. The application of L-carnitine significantly reduced abdominal fat pad (p < 0.05) and the lowest was obtained by consuming 400 mg/kg L-carnitine. L-carnitine reduces fat accumulation in tissues by altering fat metabolism (Burtle et al. 1994). Heart weight increased and the weight of duodenum decreased with the supplemntation of L-carnitine (p < 0.05). The level of cholesterol, triglycerides, and very low-density lipoprotein (VLDL) decreased with L-carnitine compared to the control (P <0.05). L-carnitine also increased total protein and HDL compared to the control. The effect of L-carnitine on albumin and glucose levels was not significant (P≥0.05). Zhang et al. (2010) reported that L-carnitine reduces blood triglycerides in broilers by increasing the catabolism of fatty acids. On the other hand, Cartwright (1986) believes that L-carnitine reduces the serum triglyceride by increasing the activity of lipase enzyme. The weight of the immune system organs (spleen, thymus, and bursa of Fabricius) were not affected by L-carnitine supplemntation (P≥0.05). The antibody titer against the Newcastle virus and the level of total immunoglobulin against SRBC was significantly increased at 35 and 42 days of age with the use of L-carnitine (p < 0.05). A group of researchers stated that L-carnitine improves the humoral response to vaccination and boosts the immune system in broilers and laying hens by producing monoclonal antibodies and increasing the tendency of white blood cells to remove foreign agents (Mast et al. 2000, Deng et al. 2006). L-carnitine Supplementation of broilers diet significantly (p < 0.05) reduced the population of clostridium, Escherichia coli, coliform bacteria and increased the population of Lactobacillus bacteria The health of digestive system is a necessity to increase performance and profitability in poultry farming. The balance between the gram-positive and negative microbial populations plays an important role in the health of the digestive system. In a healthy digestive system, the population of gram-positive bacteria is predominant (Norreh et al. 2015). L-Carnitine had a positive and significant effect on improving the sensory properties of breast meat (P <0.05) and increased the flavor of breast meat. The highest amounts of oleic acid (18: 1c) and linoleic acid (18: 2c) in breast meat were obtained using 200 and 400 mg/kg L-carnitine, respectively. Also, the length of the intestinal villi increased and the depth of the crypt decreased with increasing L-carnitine level in the diet. L-carnitine appears to improve intestinal histology by affecting the intestine microflora, reducing harmful bacteria, and increasing lactobacilli.

Considering the positive effect of L-carnitine on the traits measured in the present study, supplementing the diet of Ross 308 broiler chickens with 400 mg/kg L-carnitine is recommended to improve growth performance, carcass characteristics, blood parameters, function of immune system, cecal microbial population, histology of the small intestine, and composition of breast meat fatty acids of broiler.

Morphological changes in vital organs such as the liver, intestines and oviducts of laying hens by feeding certain compounds can affect their productive performance. This study was conducted to investigate the morphological changes in the liver, intestine and oviduct tissues of laying hens by feeding on omega-3 riched diets containing different levels of L-carnitine. One hundred tewnty laynig hens were used at 34-44 weeks of age. Laynig hens allocated into 2×3 factorial experiment with two levels of omega-3 (zero, 3%) and three levels of L-carnitine (zero, 100 and 200 mg/kg) in a completely randomized design with 6 treatments and 5 replicates and 4 birds per each. Diets containing 100 mg/kg L-carnitine increased the crypt width in intestinal (P<0.05). The effect of L-carnitine and omega-3 fatty acids on the diameter of the hepatocyte nucleus and the diameter of the hepatocyte cell in the liver was not significant. Feeding diets rich in omega-3s increased the height of the epithelium of the magnum (P<0.05). Adding 100 mg/kg of L-carnitine to normal or omega-3-rich diets increased fold height in Isthmus (P<0.05). It could be concluded that adding 100 or 200 mg/kg of L-carnitine to diets enriched by omega-3 fatty acids had no effect on hepatocyte nucleus and cell diameter. Diet containing omega-3 or adding 100 mg / kg L-carnitine to diet containing omega-3 had a negative effect on the height of intestinal villi but increased the height and thickness of the folds and epitelium tissue which can improve the production performance of laying hens. Further studies are recommended in this area.

The effect of feeding L-carnitine during pre-puberty on the quality parameters of fresh and frozen-thawed semen by using 12 Ross broiler breeder males (12 weeks) for 18 weeks, in a completely randomized design with three treatments (0, 250 and 500 mg / kg of L-carnitine in the diet) and four replications was performed. From the age of 26 to 29 weeks, semen collection was performed using abdominal massage. The sperms taken each time after dilution (with Beltsville diluent) were divided into two parts, one section was frozen and the other part was immediately examined. Motility (total and forward), viability, morphology, membrane functionality and lipid peroxidation parameters were evaluated. In fresh sperm, the correlation between L-carnitine and abnormalities was negative linear, and with viability was positive linear (P<0.05). Quadratic analysis was significant in forward Motility and MDA concentration (P<0.05). Birds that use diets containing L-carnitine, In terms of forward motility, viability, morphology and MDA concentrations in fresh sperm, And these traits, with the total motility and integrity of the plasma membrane of frozen sperm, were higher in comparison to the control group (P<0.05). Also, in the sperm after frozen-thawed, the correlation between L-carnitine and Motility (total and forward), viability and membrane integrity were positive linear (P<0.05), and the correlation between L-carnitine and MDA concentration was negative linear (P<0.05). The correlation between L-carnitine and Motility (total and forward), membrane integrity and MDA concentration were quadratic (P<0.05). According to the results, Dietary L-carnitine supplementation in pre-puberty improves the qualitative traits of sperm before and after freezing in the breeder broilers.

Use of antibiotic growth promoters (AGP) in broiler diets has been banned in the European Union and in many countries. Therefore, researches have focused on the development of alternative strategies. Various products and natural materials such as probiotics, prebiotics, organic acids, and plant extracts have been tested as effective alternatives to AGPs. L-Carnitine (β-hydroxy-γ-trimethyl amino butyrate) is a water soluble quaternary amine and exists naturally in microorganisms, plants, and animals (Dikel et al., 2010). L-Carnitine is synthesized exclusively in the liver of animals and plays a key role in energy metabolism of cells, mainly by transferring long-chain acyl groups from cytoplasm to mitochondrial matrix for β- oxidation (Dikel et al., 2010). It has been reported that the addition of L-carnitine to broiler breeder diet in early stages of growth improved their performance (Golzar-adabi et al. 2005). Inclusion of L-Carnitine to young animal diet improves use of fatty acids and their energy efficiency; therefore, it improves growth and feed conversion ratio (Zhang et al. 2010). In the folklore of many cultures, garlic (Allium sativum L.) has been widely used as a therapeutic agent. Garlic has rich organosulfur compounds and metabolites (allicin, diallyl sulfide, and diallyl trisulfide) (Kim et al., 2009). Allicin and its related compounds in garlic inhibit the HMG-CoA reductase enzyme, which plays a key role in the formation of liver cholesterol; then, allicin decreases cholesterol levels (Anthony et al. 2005). Duration of L-Carnitine and garlic supplementation in broiler chicken diet may have different effects on broiler chicken performance. Therefore, the aim of this study was to investigate the duration of supplementation of L-Carnitine and garlic powder on broiler chicken performance, serum biochemistry, carcass parameters, and meat quality. In order to consider the effects of L-carnitine and garlic powder on broiler chicken performance, blood metabolites and carcass characteristics, a total of 480 Arian one-day-old broiler chicks were allocated to 2×5 factorial arrangements in a completely randomized design with 5 dietary treatments, 4 replicates, and 12 birds in each replicate. Dietary treatments were 1) basal diet with no additive (BD), 2) BD plus 0.02% flavomycin antibiotic (positive control), 3) diet containing 1.5% garlic powder, 4) BD plus 0.025% L-Carnitine, and 5) diet containing 0.025% L-Carnitine plus 1.5% garlic powder in two periods (short term: first 3 weeks and long term: 6 weeks period). The birds were kept under conventional conditions for vaccination, temperature, ventilation, and lighting based on Arian catalogue recommendations. The birds fed experimental diets from 1 to 42 days of age and standard management practices of commercial broiler production were applied. The broiler diets were formulated based on standardized ileal digestible amino acids and other requirements were obtained from Arian catalogue recommendations. During the experiment, body weight and feed intake were recorded and finally feed conversion ratio and European production efficiency factor were calculated. From 2 birds of each pen, blood samples were collected at the end of experiment, then cholesterol, triglycerides, HDL-cholesterol, and LDL-cholesterol were detected. At 42 d, 2 broiler chickens per replicate were selected and sacrificed. Carcass, spleen, bursa of Fabricius, abdominal fat, thigh, and breast percentages were expressed as their percentages to live body weight. Thigh and breast meat pH and color were measured by pH meter (330i/SET WTW model) and electric colorimeter (1002 model- RGB Lutron), respectively. The lactate concentration of the breast meat was estimated by a spectrophotometer and calculated using the following formula (Zhang et al., 2009): Lactate concentration = 𝑂𝑝𝑡𝑖𝑐𝑎𝑙 𝐴𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑆𝑎𝑚𝑝𝑙𝑒𝑂𝑝𝑡𝑖𝑐𝑎𝑙 𝑎𝑏𝑠𝑜𝑟𝑝𝑡𝑖𝑜𝑛 𝑓𝑜𝑟 𝑠𝑡𝑎𝑛𝑑𝑎𝑟𝑑 ×22 Results showed that supplementation length and dietary treatments did not affect broiler chickens body weight, feed intake, feed conversion ratio, meat pH, serum triglyceride, cholesterol, HDL-cholesterol, and LDL-cholesterol, and breast meat lactate concentrations (P>0.05). Dietary treatments and supplementation period significantly influenced breast, bursa, and abdominal fat percentage (P<0.05). L-Carnitine positively facilitates consumption of short and medium chain fatty acids by the mitochondria (Tan et al. 2008). Therefore, the diet containing L-Carnitine stimulates the oxidation of fatty acids to produce adenosine triphosphate and use of energy. In addition, positive effect of garlic powder on performance of broiler chicks can be attributed to the antioxidant and some growth-promoting effects of this herbal plant (Anthony 2005). Conclusion It was concluded that application of the dietary supplements (0.025% L-Carnitine plus 1.5% garlic powder) in a short or long period, are not advisable for broiler chicken diets, since they make the rations more expensive.

This study was carried out to investigate the effects of in ovo feeding of L-carnitine and Satureja Khuzistanica extract on hatchability, post-hatch performance and carcass traits in broiler chickens. A total of 560 fertile eggs of Ross 308 strain (36-wk-old breeder flock) were assigned randomly to seven treatments with four replicates and 20 eggs per replicate. Treatments included control group (noninjected), dry punch, physiological saline injection, in ovo injection of L-carnitine (20 and 30 mg) and in ovo injection of Satureja khuzistanica extract (10 and 20 mg). Treatment solutions were injected into the air sac on d 17 of incubation. After hatch, 10 chicks per each replicate were distributed in pens and reared up to 42 d of age. The highest and the lowest rate of hatchability were observed respectively with injection of L-carnitine (30 mg) and Satureja khuzistanica extract (20 mg) into fertile eggs (P<0.05). In ovo administration of L-carnitine (30 mg) increased hatch weight of broiler chicks compared to other groups (P<0.05). The highest body weight gain in broiler chicks after hatch were observed in fertile eggs injected with 30 mg of L-carnitine (P<0.05). In ovo injection of L-carnitine (30 mg) into fertile chicken eggs at 17 d of incubation improved feed conversion ratio of broiler chicks after hatch (P<0.05). Therefore, it can be concluded that the in ovo administration of L-carnitine (30 mg) had positive effects on hatchability, hatching weight and feed conversion ratio in broiler chicks.

The study was conducted to investigate the effects of different levels of L-carnitine on performance, carcass characteristics and some blood parameters of broiler chickens. Two hundred day old male broiler chickens (Ross 308) assigned to 5 treatment with 4 replicates of 10 birds in each replicate were used in this experiment. Experimantal diets were: 1) basal diet; 2) basal diet + 150 mg/kg L-carnitine; 3) basal diet + 300 mg/kg L-carnitine; 4) basal diet + 450 mg/kg L-carnitine; 5) basal diet + 600 mg/kg L-carnitine. Results showed that adding L-carnitine had not significant effect on body weight gain from 0-21 d of age (P<0.05). But adding different levels of L-carnitine in diet had a significant effect on body weight gain during 0-21 d and whole period 22-42 d (P<0.05). Also had not significant effect on feed intake during 0-21 d and whole period 22-42 d. But adding L-carnitine in diet had a significant effect on feed conversion ratio during 0-21 d, 22-42 d and whole period. Result show that adding L-carnitine significantly increase the carcass weight, breast and leg meet (P<0.05). Adding different levels of L-carnitine in diet significantly decrease the abdominal fat (P<0.05) and decrease the blood cholesterol, triglyceride, LDL, VLDL and also increase the blood albumin and globulin (P<0.05). But it had not significant effect on blood glucose, total protein and HDL. The result show that adding L-carnitine in diet improve the broiler chickens performance.

The effects of L-carnitine on growth performance and carcass composition in male broiler chicks, fed diet in which CP was reduced in a stepwise manner from 21 to 18% were investigated. Ileal digestible quantities of all EAA were almost equal in the diets, with quantities NRC 1994 recommendations. One hundred forty four male commercial broilers were allotted to six groups, each with four replicates (6 birds per replicate). The experimental design was a 2×3 factorial arrangement in a completely randomized design with 21, 19.5, 18% crude protein levels and 0, 50 mg/kg of L-carnitine. Performance of birds fed the low protein diets was not significantly affected by the CP levels. Fat content in whole-body and Abdominal Fat Deposition (AFD) increased linearly as CP decreased in the diets. The feeding trial showed that L-carnitine had no significant effect on either daily gain or feed conversion. Supplementation of L-carnitine in the diet decreased abdominal fat deposition and crude fat content of the leg muscles as well as the whole body (P<0.05). Reducing dietary CP increased plasma Na, K and Cl. The results of this study indicate that dietary crude protein can be reduced up to some point and L-carnitine could reduce the deposit of fat in the birds fed low protein diet.