Hormonal response and reproductive performance of crossbred rabbit does (Oryctolagus cuniculus) fed dietary niacin supplementation under heat stress conditions

Abstract

Effect of dietary niacin supplementation was investigated on hormonal response of crossbred rabbit does (Oryctolagus cuniculus) in a 6-week feeding trial. A total of 30 matured rabbit does of 18 to 20 weeks old with average weight of 2.75 kg were used. Niacin was included in the diets of the rabbits at levels of 0 (control), 50, 100, 150 and 200 mg/kg feed. The rabbits were randomly allotted to the diets (n=6 rabbits/treatments) and housed individually. Data generated were subjected to analysis of variance while the significant differences in means were separated using pairwise-difference. Results showed that rabbit does fed dietary niacin at 100, 150 and 200 mg niacin/kg diet had significantly (P<0.05) higher oestradiol (26.02, 26.25, 26.40 vs. 24.84 pg/ml) and progesterone (8.18, 8.76, 8.90 vs. 7.63 ng/ml) concentrations as well as litter size at birth (7.50, 8.50, 7.90 vs. 6.20) and at weaning (6.80, 7.45, 7.10 vs. 5.00) than their counterparts fed the control diet. There was significant interaction between niacin levels and breeding periods on oestradiol and progesterone concentrations of the does. The results of this study suggest that feed grade niacin supplementation at 100, 150 and 200 mg niacin/kg diet could potentially improve hormonal profile which led to improved litter size at birth and at weaning of the rabbit does.