Growth, efficiency, and composition of Tilapia (Oreochromis aureus) fed with red earth worm (Eisenia fetida)

Abstract

Balanced diets for tilapias are based mainly on fishmeal, soybean meal, and other high-cost protein ingredients, making Eisenia fetida an alternative for protein substitution in feeds for these species. The objective of this research was to evaluate the effect of the substitution of the red earth worm (Eisenia fetida) in the diet of tilapia fingerlings (Oreochromis aureus) on zootechnical parameters, body indices, and chemical composition in fish carried up to the fattening phase. In the Aquaculture Module of the Alfredo Volio Mata Experimental Station (EEAVM), between May and September 2021, 8 hormonally reversed fingerlings were stocked per tank (8 tanks in total) with an initial average weight of 3.24 g ± 0.09 g. In the initial phase, two treatments were used, the control treatment (T0) and the treatment with a 50% substitution of balanced feed for the dehydrated earth worm (T1) in dry matter. In the fattening phase, the same experimental units were used, but the feed was 100% based on commercial diet. The effect of this substitution was evaluated on weight gain, increase in standard length and width, specific growth rate (SGR), feed conversion ratio (FCR), thermal growth coefficient (CTC), protein use efficiency (PER), gonadosomatic index (IGS), hepatosomatic index (IHS), viscerosomatic index (VIS), head/body ratio and final chemical composition of the fish tissue. In weight gain, increase in standard length and width, SGR, CTC, PER, IHS, IGS, and chemical composition of the tissues, no significant differences were observed (p>0.05); where as in the FCR, IVS, and head/body ratio, significant differences were obtained (p<0.05).