title: Dietary methionine requirement of Jing Brown layer hens from 9 to 17 weeks of age.
abstract: This study was conducted to evaluate the effect of dietary methionine (Met) supplementation in growth performance and reproductive performance of Jing Brown layer hens. A total of 375 9-week-old Jing Brown layer hens were allocated equally to five treatments consisting of 5 replicates with 15 hens. Hens were fed with a diet of corn and soya bean meal supplemented with 0.23%, 0.27%, 0.31%, 0.35% and 0.39% Met respectively. Different Met levels did not significantly affect average daily feed intake (ADFI), average daily gain (ADG) and feed/gain ratio (F/G) (p > 0.05), whereas flock uniformity (FU) and jejunum index were significantly different (p < 0.05), and the largest FU was observed in 0.31% Met. Dietary supplementation of Met significantly affected reproductive system development (p < 0.05), and 0.27-0.31% Met obtained optimal reproductive system development. Different Met levels significantly affected serum uric acid and alkaline phosphatase. Moreover, the relatively higher reproductive hormones in serum were observed in 0.27% Met. Analysis of quadratic curve estimation of flock uniformity, the total number of follicles, the primary follicles and the secondary follicles showed that the optimal Met levels were 0.293%, 0.286%, 0.286% and 0.288%, which could be averaged to 0.288%. These results suggested that the optimal Met requirement for Jing Brown layer hens from 9 to 17 weeks old is 0.29%.
authors.affiliation: College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China.
authors.forename: G H
authors.initials: GH
authors.lastname: Meng
authors.affiliation: College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China.
authors.forename: D
authors.initials: D
authors.lastname: Song
authors.affiliation: College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China.
authors.forename: L B
authors.initials: LB
authors.lastname: Li
authors.affiliation: College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China.
authors.forename: C J
authors.initials: CJ
authors.lastname: Yang
authors.affiliation: College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China.
authors.forename: Z X
authors.initials: ZX
authors.lastname: Qu
authors.affiliation: College of Animal Science and Technology, Northwest Agriculture and Forestry University, Yangling, Shaanxi, China.
authors.forename: Y P
authors.initials: YP
authors.lastname: Gao
mesh_terms: D000821:Animal Feed / Q000032:analysis; D000824:Animal Nutritional Physiological Phenomena; D000818:Animals; D002645:Chickens / Q000097:blood / Q000235:genetics / Q000502:physiology*; D004032:Diet / Q000662:veterinary; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D041981:Gastrointestinal Tract; D007986:Luteinizing Hormone / Q000097:blood; D008715:Methionine / Q000008:administration & dosage*; D009751:Nutritional Requirements; D006080:Ovarian Follicle; D010053:Ovary / Q000187:drug effects / Q000254:growth & development; D010057:Oviducts / Q000187:drug effects / Q000254:growth & development
chemical_list: D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D008715:Methionine
keywords: Jing Brown layer hens; dietary; growth performance; methionine; organ development