Amelioration of Anti-Nutritive Effects of Castor Oil Seed (Ricinus communis) Meal in Broilers’ Ration Using Natural Fermentation and Dl-Methionine Supplementation
Three hundred and twenty (320) day old male broilers were used to investigate the amelioration of anti-nutritive effects of castor oil seed (Ricinus communis) meal in broilers’ ration using natural fermentation and DL-Methionine supplementation. The experimental designed was a 4 × 2 factorial arrangement of dietary treatments consisting of 4 inclusion levels of fermented castor seed meal (FCASM; 0, 50, 100, and 150 g/kg) supplemented with or without 5 g/kg DL-Methionine. Growth performance, coefficient of total tract apparent digestibility, serum metabolites, dressing percentage, and retail cuts were determined at the end of the study, which lasted for 42 days. There existed a linear reduction in weight gain and poorer feed to gain ratio with increasing dietary inclusion levels of FCASM. However, broilers fed control diet (without 5g/kg DL-methionine supplement) showed similar daily weight gain, feed to gain ratio and protein efficiency ratio with birds fed diet containing 50 g/kg FCASM supplemented with 5g/kg DL-Methionine. In a similar manner, low dressing percentages recorded with broilers fed diets containing 100 and 150 g/kg FCASM without supplemental DL-Methionine were slightly improved following dietary supplementation of the diets each with 5 g/kg DL-Methionine. Relative weight of gastro-intestinal tract increased linearly (P < 0.05) while total tract apparent digestibility of crude fibre reduced quadratically (P < 0.05) with increasing dietary inclusion levels of FCASM. Total serum protein and serum uric acid concentration reduced (P < 0.05) with increasing dietary inclusion of FCASM with or without 5 g/kg DL-Met supplementation. In conclusion, supplementation of diets containing 50g/kg fermented castor seed meal with 5g/kg DL-Methionine resulted in improved growth response with no symptoms of castor toxicity. Dietary supplementation of DL-methionine thus showed prospects in masking the anti-nutritive effect of fermented castor seed meal thus improving its utilization as potential oil seed meal in broilers ration.
Keywords: Castor oil seed meal; DL-methionine; Broiler chickens; Serum metabolites