In recent years valorization of biowaste attracts lot of attention worldwide owing to its high nutritional value and low price. In this work biowaste of animal (sardines) and plant (tomato) biowaste was used to formulate a new feed for red tilapia, that showed to be competitive in its price and zootechnical performance in comparison to commercially available tilapia feeds. Mathematical modelling was used to formulate optimal feed composition with favorable chemical composition and the lowest price. Formulated feed had high protein content (40.76%) and energy value of 279.6 Kcal/100 g. Optimised feed was manufactured and compared to commercially available reference feed in respect to feed intake, feed efficiency, specific growth rate of fingerlings of Tilapia sp and, most important, zootechnical parameters. With fish survival rate of 100% calculated feed conversion index for the formulated feed was 2.7.
Key words: conversion index, fish waste, formulated feed, tomato waste
The Feed Conversion Index (CI) is an indicator commonly used in aquaculture farming, it gives an idea of the feed efficiency of a feed or feeding strategy. Slightly higher CI was observed for feed T1 (2.7). In T0 calculated CI was 2.5. For both tested feeds their CIs were similar to those obtained by Abdel-Warith et al (2001) which ranged from 1.25 to 2.80 for fingerlings fed with feeds based on avian by-products. Feed conversion rates obtained by Fagbenro et al (1999) ranged from 1.52 to 2.27 depending on whether the diet was based on soybean meal or arugula meal with percentage of incorporation of 19.5, 39 or 58.5%. The feed conversion rates obtained by Giri et al (2000) in their experiment of substituting fishmeal with chicken viscera meal or vegetable meals (soybean, peanut and mustard) were 3.0 and 2.9, respectively. Sandamali et al (2016)