Nutrients digestibility and growth performance of Nile tilapia (Oreochromis niloticus) fed on oilseed mealswith crude papain enzyme

Abstract

In this study, nutrients digestibility and growth performance of Nile tilapia (Oreochromis niloticus) fed on oilseed meals with crude papain enzyme were determined. A control diet (D1) of 30% crude protein (CP) was formulated using fishmeal (FM), soybean meal (SBM), canola meal (CM) and sunflower meal (SFM). The test diets were formulated with replacing 10% CP of FM by SBM (D2), CM (D3) and SFM (D4), respectively. Crude papain enzyme in powder form was incorporated at 0.06%. Digestibility trial was performed using chromium oxide as an inert marker. A feeding trial of 101 days was conducted using a 4 × 2 factorial design with 4 diets (D1, D2, D3 and D4) and 2 papain enzyme inclusion levels at 0.06% and 0% using 720 Nile tilapia fingerlings (7 ± 3 g). The fingerlings were randomly distributed into 8 groups of 3 replicates of 30 fingerlings per net hapa (2 × 1 × 1 m3). Fish were fed twice daily at 5% of their biomass at 10 am and 4 pm in two equal meals. Apparent digestibility coefficients increased (p < 0.05) on crude papain enzyme supplementation. There was increase in final body weight (47.32 ± 2.10 g) on 0.06% enzyme than without enzyme (0%) (46.17 ± 2.14 g) (p > 0.05). Irrespective of enzyme supplementation, fish fed FM-based diet were larger (56.89 ± 1.37 g) (p < 0.05) than those fed on oilseed meals; SBM (45.59 ± 0.91 g), CM (43.89 ± 2.12 g) and SFM (40.59 ± 1.60 g). Based on the study, 0.06% crude papain enzyme inclusion increased nutrients digestibility and growth performance of Nile tilapia. Therefore, crude papain enzyme is recommended as a feed additive in Nile tilapia diets to promote growth. However, more research is recommended to determine optimum inclusion levels of crude papain enzyme in Nile tilapia diets.