Sources of Betaine as Methyl Group Donors in Broiler Diets

Abstract

Betaine is donor of methyl groups and can partially replace methionine in diets for this purpose. The objective of this study was to evaluate three sources of betaine in partial substitution of methionine supplement in broiler diets. The Cobb-500 broiler chickens were allocated in a completely randomized experimental design with 5 treatments and 7 replicates of 49 birds each. The positive control treatment consisted of standard level of digestible methionine, the negative control was the digestible methionine reduced by 17% and the other three treatments consisted of the negative control diet supplemented with natural betaine (95%) or hydrochloride betaine (72%), HCl 1 and HCl 2 that had the same composition, and were obtained from two different manufacturers. The performance was evaluated from 7 to 21 days, 7 to 35 days and 7 to 43 days. At 43 days, the carcass and carcass parts (breast, thigh+drumstick, liver and abdominal fat) were determined and an economic analysis of each diet was performed. The performance results of the negative control were similar to the other treatments; however, there was a reduction in breast meat yield of birds fed the negative control compared to positive control and betaine HCl 2. The birds from the negative control had the lowest breast meat yield and the highest thigh + drumstick yield. The chickens fed betaine HCl 2 had greater amount of breast in the carcass (42.85 <em>vs.</em> 41.17%) and the cost of production of breast was reduced (US$1.941 <em>vs</em>. US$ 2.042) compared to the negative control. There was not difference between treatments in carcass yield, percentage of liver and abdominal fat. There was a tendency to higher abdominal fat deposition in carcass in animals fed with the negative control. As a conclusion, the inclusion of betaine in the diets of chickens containing restricted levels of methionine is economically feasible, reducing the cost of breast meat production.