Xiuan Zhan

Effects of methionine and betaine supplementation on growth performance, carcase composition and metabolism of lipids in male broilers

1. This study was conducted to investigate the effects of methionine and betaine supplementation on growth performance, carcase composition and lipid metabolism in growing broilers. 2. A total of 450 commercial broilers, 22 d of age, were randomly allocated to three groups, each of which included three replicates (50 birds per replicate). The groups received the same methionine-deficient diet supplemented with 0 or 1 g/kg methionine, or 0·5 g/kg betaine, respectively. 3. Methionine and betaine supplementation significantly improved weight gain and feed conversion. Supplemental methionine and betaine also significantly increased breast muscle yield and decreased abdominal fat content. Meanwhile, addition of methionine and betaine significantly increased the contents of creatine and free carnitine in liver, the activity of hormone-sensitive lipase in abdominal fat and the concentration of free fatty acid in serum, whereas uric acid concentration in serum was significantly decreased. 4. The results of this study suggest that betaine can spare methionine in its function as an essential amino acid and is as effective as methionine in improving performance and carcase quality of growing broilers if the diet is moderately deficient in methionine. The decrease in abdominal fat may be due to the increased carnitine synthesis in liver and hormone-sensitive lipase activity in abdominal fat.

Effects of different methionine sources on production and reproduction performance, egg quality and serum biochemical indices of broiler breeders

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. Conclusion 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.