Submitted to: Popular Publication
Publication Type: Popular publication
Publication Acceptance Date: 9/15/2013
Publication Date: 3/6/2014
Citation: Thompson, K.R., Velasquez, Patterson, J.T., Webster, C.D. 2014. Evaluation of plant and animal protein sources as partial or total replacement of fish meal in diets for juvenile Nile tilapia. Kentuck Aquatic Farming. 27(1):Winter 2013-2014. Interpretive Summary:
Technical Abstract: A feeding trial was conducted in a closed system with Nile tilapia (Oreochromis niloticus) juveniles (mean weight, 2.84 g) to examine the effects of total replacement of fish meal (FM), with and without supplementation of DL-methionine (Met) and L-lysine (Lys), by plant protein sources. Fish were fed six isoenergetic (AE = 4.0 kcal/g of diet) and isoproteic (35% protein as fed basis) practical diets containing protein primarily from soybean meal (SBM), soybean protein concentrate (SPC), feed-grade poultry by-product meal (PBM), or combinations of those ingredients. After 7 weeks, mean final weight, percentage weight gain (PWG), and amount of diet fed for fish fed diets 1 (control with 20% FM) and 6 (with 20% SPC and 20% PBM) were significantly higher (P < 0.05) compared with juveniles fed all other diets. Feed conversion ratio (FCR) was similar among treatments, but fish fed diet 5 (with 36% SPC and 0% FM) recorded the highest FCR value. Likewise, protein efficiency ratio (PER) was similar among treatments; however, PER in juveniles fed diet 3 (with 52% SBM and 0% FM) and diet 5 were significantly lower than in fish fed all other diets. Overall, no significant (P > 0.05) difference was found in percent survival, which averaged 92.6% among all diets fed. These data suggest that Nile tilapia fry cannot utilize diets containing high levels (>75%) of SBM when no animal protein ingredient is added, even with supplemental Met and Lys. However, a diet containing 20% SPC and 20% feed-grade PBM appears to be suitable for juvenile Nile tilapia, which may help reduce diet costs and allow for sustainable production.