Supplementation of diets with Brazil nut powder can meet dietary methionine requirement of organic broiler chickens

Abstract

Synthetic amino acids are not permitted in organic feeds by the National Organic Standard Board (NOSB) in the USA. However, low levels of methionine (Met) are permitted, and the NOSB recommends 0.1% synthetic Met for broilers. Inadequate level of dietary methionine poses concerns pertaining to health and welfare of broilers, as these limitations lead to possible Met deficiency. This research examined the effects of complete replacement of synthetic DL-methionine (DLM) by Brazil nut powder in a 100% organic diet. Eight hundred Ross 308 chicks were hatched and randomly divided into 4 treatments with 4 replicates of 50 chicks and raised for 56 days. Treatments included birds fed a conventional diet and raised organically (Conv_Org), NOSB diet raised organically (NOSB_Org), 100% organic diet and raised organically (Org_Org), and a conventional diet raised conventionally (Conv_Conv). Body weight at 56 days were 3960, 3995, 3981, and 3676 g for Conv_Org, NOSB_Org, Org_Org, and Conv_Conv, respectively. Body weights of the Conv_Conv group were lower (P < 0.05) than the other treatments. The FCR (0–8 weeks) of Org_Org treatment was lower (P < 0.05) than the NOSB diet. The birds on the NOSB diet had increased feed intake perhaps to compensate for the deficiency in Met. The NOSB diet may not sufficiently meet the requirement of broiler chickens even when raised with access to pasture. There were no differences in carcass yield and composition in any treatment. We conclude that Brazil nut powder is a viable substitute for DLM in organically raised broilers, as there were no differences in growth and carcass yield and improved FCR when compared to current NOSB recommended diet.