Effect of betaine, a methyl group donor, on broiler chicken growth performance, breast muscle quality characteristics, oxidative status and amino acid content

This study was aimed to investigate the effect of feed supplemented with betaine on broiler chickens' growth and slaughter performance, breast muscle histomorphometric and physicochemical properties, oxidative status and amino acid content. A total of 1000 1-day-old Ross 308 broiler chickens were divided into four treatments. Control group chickens were fed with standard compound diet (SCD), the chickens from experimental groups B1, B2 and B3 receiving SCD supplemented with 1 g/kg (B1), 2 g/kg (B2) and 3 g/kg (B3) betaine anhydrous, respectively. Each treatment had five replicate pens. Feeding test results showed that betaine reduced broilers' mortality but increased feed conversion ratio (p < .05). Forty broiler chickens (5 weeks old) were slaughtered and slaughter performance showed that 2 g/kg betaine inclusion improved breast muscle percentage and yield (p < .05). Betaine dosage of 1 g/kg into feed increased breast muscle fibre areas (p < .05). Betaine affected some physicochemical properties: higher a* and the highest drip loss in B2; the highest cooking losses in B1, B2; the highest shear force and fat content in SCD; the highest amounts of ashes in B1, B2 (p < .05). Lower malondialdehyde levels were observed in all betaine-treated groups (p < .05), except B1 fresh meat samples. The highest total amino acid content and a greater amount of essential amino acids were obtained in SCD breast muscles (p < .05), except equally highest amounts of methionine were found in both SCD and B3 samples (p < .05). However, according to our study results, betaine, as a methyl group donor, in broiler chicken diets cannot replace methionine as an essential amino acid.