Effect Of Methionine And Betaine On Growth And Carcase Characteristics Of Broiler

In order to provide scientific foundation of reasonable application for methionine and betaine in feed. The present study was conducted to compare the effects of different levels of DL-methionine with DLM-Bet mixture on growth performance, carcase traits and metabolism of lipids in broiler chickens and discussed the sparing methionine effect of betaine. Regression analysis was used to calculate the methionine requirement of broiler in 9 to 21 d or 22-42 d in the present experiment diets.A total of 946 nine-day-old Arbor Acres broiler chicks were used. The feeding programme consisted of a starter diet from 9 to 21 d, and a finisher diet till the end of the experiment. In a 2×5 factorial plus a control arrangement with 7 replicates of 12 Arbor Acres male broiler chickens per treatment. The basal diet contained 0.30% (9-21 d) or 0.28% (22-42 d) methionine. DLM and DLM betaine mixture (DLM-Bet,75% DLM and 25 % betaine) were supplemented at equal quality levels of 0.04, 0.08, 0.12, 0.16, 0.20%, and 0.03, 0.06, 0.09, 0.12 and 0.15% for 9-21 d and 22-42 d, respectively.The results showed that adding DLM could significant improved the BWG and FCR (P<0.05), supplement 0.12% DLM have the highest BWG and FCR. DLM-Bet treatments not improved BWG in 9-21 d, while significant increased BWG in 22-42 d and FCR both in 9-21 d and 22-42 d. No significant different was found in feed intake on both growth stages. In 9-21 d supplementing DLM have higher BWG than DLM-Bet treatments, and tend to have better FCR, but no significant different was observed in BWG and FCR in 22-42 d.Supplement DLM had higher breast rate than DLM-Bet treatments in 21 d, no significant different was observed on in 42 d. Different levels of DLM or DLM-Bet significantly (P<0.05) changed the PDAF (Percentage of Dissected Abdomen Fat) on 21 d or 42 d Broke-line regression analysis showed that methionine requirement was 0.46 % during 9-21 d and 0.34% (Regression using BWG) or 0.31% (Regression using feed efficiency) during 22 to 42 d in this study.The results suggested that betaine can not substitute for methionine in broilers fed diets that are marginally deficient in methionine. In 22-42 d, broilers in DLM-Bet treatments could occur compensatory growth. Broilers in the present study diet, methionine requirement could decrease to 80% of recommendation requirement.