title: Effects of different methionine sources on production and reproduction performance, egg quality and serum biochemical indices of broiler breeders.
abstract: OBJECTIVE
  The study was conducted to evaluate the effects of different methionine (Met) sources on production performance, reproduction performance, egg quality and serum biochemical indices in broiler breeders.
  
  
  METHODS
  After receiving a basal diet (containing 0.25% Met) for a 2-wk pretreatment period, a total of 360 39-wk-old Lingnan yellow broiler breeders were randomly allocated to four treatments with six replicates each (15 birds per replicate). Breeders were fed with basal diets (control) or diets supplemented with DL-methionine (DLM), DL-2-hydroxy-4-methylthio butytric calcium (MHA-Ca) and coated DL-Met (CME) respectively.
  
  
  RESULTS
  The results showed that CME supplementation promoted laying rate and decreased feed-to-egg ratio (F/E) (p<0.05), DLM and MHA-Ca supplementation decreased F/E (p<0.05) when compared with control group. The rate of fertility, hatchability and birthrate were higher (p<0.05) in DLM, MHA-Ca, and CME groups than control group. Compared with control group, CME increased the eggshell thickness (p<0.05); MHA-Ca improved the eggshell thickness, shell ratio and eggshell strength (p<0.05). Results also showed that CME elevated the concentration of total protein in serum (p<0.05); MHA-Ca improved the concentration of calcium in serum (p<0.05). The concentration of serum uric acid in DLM, MHA-Ca, and CME groups was lower than that in control group (p<0.05). Besides, CME had higher concentrations of serum taurine, cysteine and cystanthionine (p<0.05) while MHA-Ca and DLM promoted the serum taurine concentration (p<0.05) compared with control group.
  
  
  CONCLUSIONS
  Based on the results, it was concluded that Met supplementation could enhance the production and reproduction performance as well as the antioxidant status and egg quality of broiler breeders. In terms of improving the production performance, reproduction performance and antioxidant performance, CME was superior to DLM and MHA-Ca; but in regard to the enhancement of eggshell quality and serum Ca concentration, MHA-Ca was superior to DLM and CME.
authors.affiliation: Feed Science Institute, College of Animal Science, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Xue
authors.initials: X
authors.lastname: Xiao
authors.affiliation: College of Animal Science and Technology, Zhejiang Agricultural and Forestry University, Lin'an, Zhejiang 311300, China.
authors.forename: Yongxia
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Animal Husbandry and Veterinary Bureau, Tongxiang, Zhejiang 314500, China.
authors.forename: Weilong
authors.initials: W
authors.lastname: Liu
authors.affiliation: Feed Science Institute, College of Animal Science, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Tingting
authors.initials: T
authors.lastname: Ju
authors.affiliation: Feed Science Institute, College of Animal Science, Zhejiang University, Hangzhou, Zhejiang 310058, China.
authors.forename: Xiuan
authors.initials: X
authors.lastname: Zhan
keywords: Broiler Breeder; Methionine; Production Performance; Reproduction Performance; Serum Biochemical Indices