EFFECT OF DIETARY LUPIN (Lupinus angustifolius) WHOLESEED MEAL PROTEIN ON THE GROWTH OF TILAPIA (Oreochromis niloticus) REARED IN TANKS

Abstract

SUMMARY A factorial feeding experiment (2 × 5) was conducted in indoor circular 1 m 3 fiberglass tanks to evaluate the effect of different levels of un-cooked and cooked lupin whole-seed meal protein, at the expense of fish meal (FM) protein, on the growth of Nile tilapia, Oreochromis niloticus, fingerlings (3 g/fish). Nine isocaloric and isonitogenous diets (25 % protein) were formulated where FM protein was replaced partially by 0, 15, 30, 45 and 60 % of un-cooked or cooked whole lupin seed meal protein. Tanks were stocked with 15 fish/tank in duplicate groups/treatment. Fish were fed daily at a rate of 3 % of fish live body weight for 14 weeks. The results indicated that fish receiving diets containing uncooked lupin protein were better in growth performance, feed and nutrient utilization than those fed cooked lupin protein. Growth performance, feed intake, feed conversion ratio and energy utilization began to deteriorate significantly at 45 % lupin protein. Protein efficiency ratio and protein productive values declined significantly subsequent to 30 % lupin protein level. Fish fed diets containing 0, 15 and 30 % lupin protein gained preferable FCR. Dry matter and hepatosomatic index were not affected by lupin protein levels or lupin treatments whil, ash and gross energy contents were affected by lupin protein levels but not lupin treatments. Meanwhile, crude protein and ether extract were affected by both lupin protein levels and lupin treatments. The economic evaluation was in favor of diets containing 15, 30 and 60 % un-cooked in addition to 30 % cooked lupin protein. However, the results of this study indicate that up to and including 30 % lupin protein could replace FM protein in Nile tilapia diets without any retardation in growth.