1- , Department of Animal and Poultry Nutrition, Faculty of Animal Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
2- Department of Animal and Poultry Nutrition, Faculty of Animal Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
3- Department of Animal and Poultry Science, Faculty of Agricultural Technology, University of Tehran, Pakdasht, Tehran, Iran
2- Department of Animal and Poultry Nutrition, Faculty of Animal Sciences, Gorgan University of Agricultural Sciences and Natural Resources, Gorgan, Iran
3- Department of Animal and Poultry Science, Faculty of Agricultural Technology, University of Tehran, Pakdasht, Tehran, Iran
Abstract: (357 Views)
Extended Abstract
Background: Laying hens show their genetic potential when they receive all the nutrients they need in full. Today, nutritional requirements have actually increased due to advances in breeding programs and extensive selection to maximize production. In recent years, L-arginine has been considered a potential feed additive in terms of anabolic-nutritional processes due to its metabolic functions for protein synthesis. However, due to the incomplete uricotelic function and urea cycle of birds, poultry are completely dependent on dietary sources of this amino acid. Copper sulfate is a trace source of the essential element copper, which plays an important role as a cofactor in cytochrome oxidase, lysyl oxidase, superoxide dismutase, beta-hydroxylase, and ceruloplasmin, and can increase egg production and egg weight traits and reduce skeletal system problems. Therefore, this study aimed to investigate the effect of copper and L-arginine on the performance, physiological maturity, and egg quality in the early laying period of laying hens.
Methods: The effects of dietary copper and L-arginine on production performance, physiological maturation, and egg quality were studied during the early layer phase of laying hens (a total of 288 Hy-Line W-80 white laying hens, 18-week-old) in 2 × 3 factorial arrangements with two levels of supplemental Cu (8 and 16 mg/kg in the layer diet denoted as Cu8, Cu16) and three levels of LA. These included the recommended level according to Hy-line (RHL), as well as 20% higher (LA20) and 40% higher (LA40) than the recommended level in the diet. The experiment was designed as a randomized complete block with six treatments of six replicates each, with eight birds per cage, for 4 weeks. The eggs produced were collected daily, and after weighing, the percentage of laying, feed consumption, conversion factor, average egg weight, and egg shape index were calculated weekly. On the last 2 days of each week, the eggs produced by each experimental unit were collected and tested for qualitative traits, such as shell thickness, shell weight, albumen percent, haugh unit, etc. Feed intake of the experimental units was calculated from the fraction of feed consumed at the end of the period from the feed allocated at the beginning of the period, based on chick days. Maturation variables, including body weight and length, shoulder length and width, beak length (top and bottom), neck length, wing length, leg length and diameter, toe length, and talon length were measured at the end of 21 weeks. Data were analyzed in a randomized complete block design with a 3 × 2 factorial arrangement using SAS software.
Results: The height of birds’ comb increased when fed diets containing Cu8+LA40 and Cu16+LA40, compared to those fed on the Cu8+RHL diet (P < 0.05). The shank diameter increased in birds fed with Cu8+LA40 treatment, compared to those fed on the Cu16+LA20 diet (P < 0.05). Egg production of the birds increased in response to the Cu16+LA40 diet, compared to those fed with the Cu8+RHL diet (P < 0.05). Dietary supplementation of Cu16+LA40 decreased the feed conversion ratio (FCR) compared to those fed Cu8+LA40 and Cu8+RHL treatments (P < 0.05). The egg shape index increased in the birds fed Cu8+LA40, compared to the Cu8+RHL diet (P < 0.05). Egg shell strength increased in the birds fed diets containing Cu16+RHL and Cu16+LA40 compared to diets containing Cu8+LA20 (P < 0.05).
Conclusion: According to the results of this experiment, adding 16 mg of copper/kg with 20% and 40% higher than the recommended level in the production phase diets of laying hens not only improved sexual maturation physiologically but also increased the production performance and egg quality in laying hens during the early layer phase.
Background: Laying hens show their genetic potential when they receive all the nutrients they need in full. Today, nutritional requirements have actually increased due to advances in breeding programs and extensive selection to maximize production. In recent years, L-arginine has been considered a potential feed additive in terms of anabolic-nutritional processes due to its metabolic functions for protein synthesis. However, due to the incomplete uricotelic function and urea cycle of birds, poultry are completely dependent on dietary sources of this amino acid. Copper sulfate is a trace source of the essential element copper, which plays an important role as a cofactor in cytochrome oxidase, lysyl oxidase, superoxide dismutase, beta-hydroxylase, and ceruloplasmin, and can increase egg production and egg weight traits and reduce skeletal system problems. Therefore, this study aimed to investigate the effect of copper and L-arginine on the performance, physiological maturity, and egg quality in the early laying period of laying hens.
Methods: The effects of dietary copper and L-arginine on production performance, physiological maturation, and egg quality were studied during the early layer phase of laying hens (a total of 288 Hy-Line W-80 white laying hens, 18-week-old) in 2 × 3 factorial arrangements with two levels of supplemental Cu (8 and 16 mg/kg in the layer diet denoted as Cu8, Cu16) and three levels of LA. These included the recommended level according to Hy-line (RHL), as well as 20% higher (LA20) and 40% higher (LA40) than the recommended level in the diet. The experiment was designed as a randomized complete block with six treatments of six replicates each, with eight birds per cage, for 4 weeks. The eggs produced were collected daily, and after weighing, the percentage of laying, feed consumption, conversion factor, average egg weight, and egg shape index were calculated weekly. On the last 2 days of each week, the eggs produced by each experimental unit were collected and tested for qualitative traits, such as shell thickness, shell weight, albumen percent, haugh unit, etc. Feed intake of the experimental units was calculated from the fraction of feed consumed at the end of the period from the feed allocated at the beginning of the period, based on chick days. Maturation variables, including body weight and length, shoulder length and width, beak length (top and bottom), neck length, wing length, leg length and diameter, toe length, and talon length were measured at the end of 21 weeks. Data were analyzed in a randomized complete block design with a 3 × 2 factorial arrangement using SAS software.
Results: The height of birds’ comb increased when fed diets containing Cu8+LA40 and Cu16+LA40, compared to those fed on the Cu8+RHL diet (P < 0.05). The shank diameter increased in birds fed with Cu8+LA40 treatment, compared to those fed on the Cu16+LA20 diet (P < 0.05). Egg production of the birds increased in response to the Cu16+LA40 diet, compared to those fed with the Cu8+RHL diet (P < 0.05). Dietary supplementation of Cu16+LA40 decreased the feed conversion ratio (FCR) compared to those fed Cu8+LA40 and Cu8+RHL treatments (P < 0.05). The egg shape index increased in the birds fed Cu8+LA40, compared to the Cu8+RHL diet (P < 0.05). Egg shell strength increased in the birds fed diets containing Cu16+RHL and Cu16+LA40 compared to diets containing Cu8+LA20 (P < 0.05).
Conclusion: According to the results of this experiment, adding 16 mg of copper/kg with 20% and 40% higher than the recommended level in the production phase diets of laying hens not only improved sexual maturation physiologically but also increased the production performance and egg quality in laying hens during the early layer phase.
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