Use of soybean flour-poultry meat meal blends in practical diets of Oreochromis Niloticus and Clarias Gariepinus

Abstract

The present study evaluated the use of improved soybean flour (SF) through autoclaving and blending with a readily available lowcost animal protein - poultry meat meal (PMM). Enrichment of such blends with dl-methionine, mineral supplementation and substitution of fishmeal with these blends in practical diets for Oreochromis niloticus and Clorias gariepinus were also investigated. Nutrient apparent digestibility coefficients (ADC) and apparent amino acid availability (AAAA) of diets based on 25:75, 50:50 and 75:25 SF- PMM were assessed. Lipid had the highest ADC while ash had the lowest. Best protein ADC and AAAA were obtained in the 0.5% Cr203 treatment which corresponded to the lowest level of faecal crude protein. Average AAAA agreed with the pattern of overall protein digestibility in the fingerlings of both species. Methionine was the most available while cystein was least. Study on utilisation of SF-PMM Blends as dietary protein source in practical diets of O.niloticus and C. gariepinus showed that 50:50 SF:PMM was best utilised with lowest food conversion ratio (FCR), highest specific growth rate (SGR), and best protein efficiency ratio (PER). Autoclaving of raw SF before blending with PMM did improve nutrient utilisation of the blends as diets containing autoclaved SF did better than those containing raw SF. Substitution of fishmeal a t 25%, 50% and 75% with these blends showed best utilisation of the 25:75 SF:PMM blend replacing 25% fishmeal in O.niloticusand 50:50 SF:PMM blend replacing 25% fishmeal in C.gariepinus. There was consistently better utilisation of dl-methionine supplemented diets in most cases. The essential amino acid profile in the diet correlated positively with that of the carcass. (P<0.05). Reconstitution of mineral premix in 50:50 blend based diet did not affect nutrient utilisation (p>0.05). However, there was significant correlation of dietary and carcass phosphorus in both species and tha t of calcium only in C. gariepinus (P<0.05). In conclusion, there was enhanced utilisation of SF by both fish species with these treatments.