Cannibalism, growth performance, and body composition of giant trahira juveniles under different photoperiods

Shayenne Elizianne Ramos,Carlos Alberto Mourão Júnior,Ana Carina Nogueira Vasconcelos,Aline Ferreira Souza De Carvalho,Galileu Crovatto Veras,Tássia Flávia Dias Castro,Luis David Solis Murgas

doi:10.1590/s0100-204x2018000600002

Abstract

Abstract: The objective of this work was to determine the effect of photoperiod on the cannibalism, growth, and body composition of giant trahira (Hoplias intermedius) juveniles. A completely randomized design was employed, with four photoperiods - 0L:24D, 6L:18D, 12L:12D, and 18L:6D, hours of light (L): dark (D) - and four replicates, for a period of 90 days. The analyzed parameters were: cannibalism, growth in weight and length, food consumption, feed conversion, protein efficiency rate, muscle growth, and body composition (moisture, lipid, ash, and crude protein). Fish from the 12L:12D photoperiod showed the highest survival rate and no cannibalism, as well as a great uniformity for length and mass values at the end of the experiment. The best photoperiod for giant trahira juveniles is 12L:12D, as these fish showed growth uniformity and no cannibalism, while fish from the 6L:18D and 18L:6D groups had a greater diameter of white muscle fibers and a higher frequency of greater diameter fibers. Giant trahira showed the lowest value for lipids at 6L:18D and the highest value at 12L:12D. Photoperiod affects survival and cannibalism; regarding body composition, only lipids are influenced by photoperiod.

Highlights

IntroductionThe giant trahira Hoplias intermedius (Günther, 1864) has aroused the interest of researchers and farmers as a potential fish for aquaculture purposes
The giant trahira Hoplias intermedius (Günther, 1864) has aroused the interest of researchers and farmers as a potential fish for aquaculture purposes.This fish adapts well to captive conditions, has quality meat, high rate of mass gain, and shows features for sport fishing
The study was conducted at the photoperiod laboratory of fish in the Biotério Central of Universidade Federal de Lavras, in the municipality of Lavras, in the state of Minas Gerais (MG), Brazil, from June 02 to October 28, 2012

Summary

Introduction

The giant trahira Hoplias intermedius (Günther, 1864) has aroused the interest of researchers and farmers as a potential fish for aquaculture purposes. This fish adapts well to captive conditions, has quality meat, high rate of mass gain, and shows features for sport fishing. Population factors, as size and density, have been correlated with the incidence of cannibalistic behavior (Naumowicz et al, 2017). Environmental factors such as feed, diet supplementation, refuges, color, and shape of tanks, light intensity, photoperiod, and temperature can increase cannibalism (Naumowicz et al, 2017). The size uniformity of H. intermedius has been considered important to minimize cannibalism (Luz et al, 2000)

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