L. C. Nwanna¹ , S. E. Olusola^1,2

1. Department of Fisheries and Aquaculture Technology, Federal University of Technology, Akure, Nigeria
2. Department of Aquaculture and Fisheries Management, University of Ibadan, Ibadan, Nigeria
Author    Correspondence author
International Journal of Aquaculture, 2014, Vol. 4, No. 15   doi: 10.5376/ija.2014.04.0015
Received: 27 Mar., 2014    Accepted: 28 Apr., 2014    Published: 02 Jun., 2014

This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Nwanna and Olusola, 2014, Effect of Supplemental Phytase on Phosphorus Digestibility and Mineral Composition in Nile Tilapia (Oreochromis niloticus), International Journal of Aquaculture, Vol.4, No.15: 89-95 (doi: 10.5376/ija.2014.04.0015)

In this study, the effect of supplemental phytase on phosphorus digestibility and mineral composition of Oreochromis niloticus fingerlings by dietary intake was investigated. Six experimental diets: 0 (control), 2,000units, 4,000units, 6,000units, 8,000units and 10,000units phytase/kg diets were formulated and replicated twice at 30% crude protein. Fish were fed twice daily at 5% body weight for 63 days. The Apparent Digestibility Coefficient (ADC) for protein, gross energy and lipid and mineral composition (Ca, Mg, P, Fe, Zn, Mn) of the fish were investigated using standard methods. Data were analyzed using descriptive statistics and ANOVA at p= 0.05. Results of apparent digestibility coefficient for protein (60.50±0.04), gross energy (64.30±0.02) and lipid (63.70±0.05) were best in fishes fed diet 5 (8,000 units phytase/kg diet) compared with the same value in fishes fed all the other diets. The mineral composition (Ca, Mg, P, Fe, Zn, Mn) of the fishes were significantly different (p < 0.05) among the treatments. However, the group of fishes fed diets that contained phytase had better mineral composition compared to the control. Also, the fish faecal showed a downward trend in the value of the minerals with increase in the level of phytase in the diets. These results indicate that using phytase as a supplement in plant – based diets may be useful in improving feed acceptability, efficiency and mineral composition of cultured O. niloticus.

Oreochromis niloticus; Mineral composition; Soybeans; Phytase; Digestibility