Locally available protein sources in diets of Nile tilapia (Oreochromis niloticus) : A study of growth performance in the Mekong Delta in Vietnam

Sammanfattning: Growth performance of male-fish Nile tilapia (Oreochromis niloticus) fed with locally available protein sources was evaluated in an attempt to find alternative ingredients to replace fish meal (FM) in an experimental set up at the An Giang University in the Mekong Delta in Vietnam. In the four experimental diets, 100 % of the FM was replaced with protein from golden apple snail meal (GAS), pangasius by-product meal (PBM), shrimp head meal (SHM) and blood meal (BM), respectively. A control diet contained FM as the main protein source. All diets were formulated containing a dietary crude protein level of 32 %. The experimental diets were prepared manually from dry feed at the experimental location. The ingredients were mixed before the feed were pelleted and sun-dried for two days. The fish were manually fed twice a day during the experimental period of 61 days. The growth parameters estimated in this study were: total weight gain (WG), specific growth rate (SGR), daily weight gain (DWG), feed conversion ratio (FCR), feed intake (FI), protein intake (PI) and survival rate (SR). The growth performance did not differ (P>0.05) between Nile tilapia fed with the control diet and the diet with PBM in any of the measured growth parameters. The experimental diets containing GAS, SHM and BM showed significant lower growth performance compared to the control and PBM diets. The results showed that pangasius by-product meal may replace fish meal by 100 % with no adverse effect on the growth performance. Total replacement of FM by GAS, SHM and BM resulted in low growth performance which could indicate that these ingredients can not totally replace FM in diet of Nile tilapia as these diets were prepared in this study.