Reassessment of riboflavin requirement for single comb White Leghorn pullets from 0 to 6 weeks of age fed on maize-soyabean meal diets and its subsequent effect on sexual maturity and egg production

1. Two experiments were conducted using a total of 228 Hyline W-26 1-d-old pullets in each experiment. The purpose of the study was to reassess the riboflavin requirement from 0 to 6 weeks of age (WOA) and its subsequent effect on sexual maturity and egg production using a maize-soybean meal diet. 2. Approximately 10% incidence of curly toe paralysis was observed among birds fed on the diet with no added riboflavin (1.5 mg total riboflavin/kg diet). 3. Applying the non-linear regression model to the body weight gain data at 3 and 6 WOA in both the experiments, it was found that the minimum total riboflavin required to achieve maximum body weight gain for the two age periods was 2.3 and 2.0 mg/kg of the total diet. This is equivalent to 5.0 and 5.7 micrograms riboflavin/g of body weight gain from 0 to 3 and 3 to 6 WOA respectively. 4. Birds fed on the diet containing no added (1.5 mg total/kg) riboflavin laid fewer eggs and had lower body weights at 24 weeks. 5. We conclude that, from 0 to 6 WOA, at least 2.3 mg total riboflavin/kg should be present in the diet to prevent curly toe paralysis, obtain the maximum body weight gain and sustain the subsequent performance at sexual maturity.