title: Effect of dietary vitamin A on reproductive performance and immune response of broiler breeders.
abstract: The effects of dietary vitamin A supplementation on reproductive performance, liver function, fat-soluble vitamin retention, and immune response were studied in laying broiler breeders. In the first phase of the experiment, 1,120 Ross-308 broiler breeder hens were fed a diet of corn and soybean meal supplemented with 5,000 to 35,000 IU/kg vitamin A (retinyl acetate) for 20 weeks. In the second phase, 384 Ross-308 broiler breeder hens were fed the same diet supplemented with 5,000 to 135,000 IU/kg vitamin A (retinyl acetate) for 24 weeks. The hens' reproductive performance, the concentrations of vitamins A and E in liver and egg yolk, liver function, mRNA expression of vitamin D receptor in duodenal mucosa, antibody titers against Newcastle disease virus vaccine, and T-cell proliferation responses were evaluated. Supplementation of vitamin A at levels up to and including 35,000 IU/kg did not affect reproductive performance and quadratically affected antibody titer to Newcastle disease virus vaccine (p<0.05). Dietary addition of vitamin A linearly increased vitamin A concentration in liver and yolk and linearly decreased α-, γ-, and total tocopherol concentration in yolk (p<0.01) and α-tocopherol in liver (p<0.05). Supplementation of vitamin A at doses of 45,000 IU/kg and above significantly decreased egg weight, yolk color, eggshell thickness and strength, and reproductive performance. Dietary vitamin A significantly increased mRNA expression of vitamin D receptor in duodenal mucosa (p<0.05), increased aspartate amino transferase activity, and decreased total bilirubin concentration in serum. Supplementation of vitamin A at 135,000 IU/kg decreased the proliferation of peripheral blood lymphocytes (p<0.05). Therefore, the maximum tolerable dose of vitamin A for broiler breeders appears to be 35,000 IU/kg, as excessive supplementation has been shown to impair liver function, reproductive performance, and immune response.
authors.affiliation: State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Jianmin
authors.initials: J
authors.lastname: Yuan
authors.affiliation: State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China; Faculty of Environmental Agricultural Sciences, Suez Canal University, Ismaïlia, Egypt.
authors.forename: Abdelfatah Rashad
authors.initials: AR
authors.lastname: Roshdy
authors.affiliation: State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Yuming
authors.initials: Y
authors.lastname: Guo
authors.affiliation: State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Yongwei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Lab of Animal Nutrition, College of Animal Science and Technology, China Agricultural University, Beijing, China.
authors.forename: Shuangshuang
authors.initials: S
authors.lastname: Guo
mesh_terms: D000818:Animals; D002645:Chickens; D019587:Dietary Supplements; D004530:Egg Yolk / Q000276:immunology / Q000378:metabolism; D005260:Female; D008099:Liver / Q000276:immunology / Q000378:metabolism; D008297:Male; D009522:Newcastle disease virus / Q000276:immunology; D012098:Reproduction / Q000187:drug effects / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D014765:Viral Vaccines / Q000276:immunology / Q000494:pharmacology; D014801:Vitamin A / Q000493:pharmacokinetics / Q000494:pharmacology; D014810:Vitamin E / Q000276:immunology / Q000378:metabolism; D014815:Vitamins / Q000493:pharmacokinetics / Q000494:pharmacology
chemical_list: D014765:Viral Vaccines; D014815:Vitamins; D014801:Vitamin A; D014810:Vitamin E