Abstract

A 60-day growth trial was conducted to evaluate growth performance, nutrient utilisation, carcass traits and feeding costs in Nile tilapia juveniles (1.47± 0.31 g body weight) fed diets in which 50% of fishmeal dry matter (DM) in the reference diet (REFD) was replaced with cattle blood, fish frames, freshwater shrimp or brewery spent yeast on a DM basis. The fish were fed 10% of body weight three times a day for the first 30 days, and then 5% of body weight twice a day for the remaining 30 days of the feeding trial. Due to high feed intake, the highest weight gain, final weight and average daily weight gain were recorded in fish fed REFD. Feed conversion ratio was lower in the diet with cattle blood than in the other diets and the protein efficiency ratio were higher for REFD than for the other diets. There were no differences in survival rate, condition factor, hepatosomatic index and viscerosomatic index between treatments. Initial and final whole body composition differed, but there were no differences in carcass traits between treatments. Feed costs per kg feed and feed costs per weight gain were reduced when fishmeal was replaced with locally available feed ingredients, with the largest reduction in feed costs per kg feed (34%) and per weight gain (27.1%) obtained with brewery spent yeast. The results indicate that the economics of small-scale tilapia production in Tanzania can be improved by replacing fishmeal with good-quality, low-cost, locally available feed ingredients.

Published in

Livestock Research For Rural Development
2020, volume: 32, number: 11, article number: 178

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