Abstract:
This study assessed the replacement value of maize with Persea americana seed meal on the diet of Clarias gariepinus juveniles. Nutrient composition of the P. americana that included proximate composition, fatty acid profile, mineral analysis were determined using standard procedures before the feeding trial. Two hundred and seventy (270) Clarias gariepinus juveniles with mean weight of 5.40±0.01g were randomly distributed into 60-litre capacity rectangular plastic troughs (60 cm x 30 cm x 30 cm) at a stocking density of 15 fish per tank. Nine diets with crude protein of 40% were formulated using Pearson Square method with different inclusion levels of P. americana seed meal. Fish were fed vary inclusion level of P. americana seed meal with coat and seed meal without coat at 0%, 25%,50%,75% and 100% respectively. The fish were fed at 5% of body weight twice a day between 08.00-09.00hr and 16.00-17.00hr GMT for a period of 56 days. Feed consumption and fish weight were measured weekly during the experimental period. At the end of the 56-day experiment, growth performance, protein nutrient utilization, digestibility was analyzed and histological changes were observed. Results showed that fish fed diet containing 0% and 50% WSC had the best growth performance with a mean weight gain of 57.15±10.52g and 49.93±47.18g respectively. Clarias gariepinus juveniles fed diets containing 25% WOSC showed the best growth performance and nutrient utilization with a mean weight gain of 50.67±9.79g. Feed conversion Ratio (FCR) and Protein Efficiency Ratio (PER) was best at fish fed diet containing 0% and 50% WSC and 25% WOSC respectively. The least weight gain (34.60±7.93g), poorest FCR and PER (1.45±0.03 and 1.73±0.04 respectively) were observed in fish fed diet containing 75% WOSC. The highest ADCs of Protein (92.10 ±0.29) were obtained in fish fed with 0% WSC, with the lowest value (89.72 ±0.15) obtained in diet fed 75% WSC while the highest ADCs of Carbohydrate (61.95 ±0.21) were obtained in fish fed 75% WSC, with the lowest value (55.29 ±2.96) obtained in diet containing 25% WSC. Histology results showed that no adverse effect of P. americana on the kidney of the fish fed experimental diets up to 75% WOSC and up to 50% WOSC for the liver. Therefore, P. americana can successfully replace maize up to 50% WSC and 25% WOSC of the inclusion level in Clarias gariepinus juveniles diet when growth and health implications were considered.
