Soybean Meal Substitution with Roselle (Hibiscus sabdariffa L.) Seed Meal in Dry Practical Diets for Fingerlings of the African Catfish, Clarias gariepinus (Burchell 1822)

摘要

Roselle (Hibiscus sabdariffa var. sabdariffa L.) seed meal was evaluated, in digestibility and feeding experiments, as a protein source in dry pelleted diets (400g crude protein, 120g crude lipid and 19.0 MJ gross energy.kg-1 DM) for the African catfish, Clarias gariepinus (Burchell 1822). The diets contained Roselle seed meal as replacement for soybean meal in a control diet and were hand-distributed to catfish fingerlings (mean initial weight, 15.6?0.5g) to apparent satiation twice daily for 70 days. Catfish mortality was low (60% of soybean meal protein, caused by reduced appetite, apparent deficiency in lysine and effects of residual antinutrients (tannin, protease inhibitors, phytic acid and gossypol) in Roselle seed meal. The toxicity of the antinutrients was however light as it did not manifest histological abnormalities in the liver. Results indicated that up to 60% of soybean meal protein can be replaced with Roselle seed meal without affecting growth performance and nutrient utilization in catfish.