Effect of dietary l-tryptophan on cannibalism, survival and growth in pikeperch Sander lucioperca (L.) post-larvae

Zdzisław Zakęś,Jarosław Król

doi:10.1007/s10499-015-9936-1

Abstract

The effect of supplemented commercial diets with crystalline l-tryptophan (TRP—5, 10 and 20 g TRP kg−1) on cannibalism, survival and growth parameters of pikeperch post-larvae (Sander lucioperca) was evaluated. Fifteen-day-old pikeperch larvae (mean weight—6.8 mg) were reared during the next 28 days (20.5 °C, 16L:8D) in glass aquaria in a recirculating aquaculture system. The enzyme-linked immunosorbent assay showed that TRP-supplemented diets were effective in increasing the levels of serotonin (5-HT) in the body tissue of pikeperch. TRP supplementation resulted in a slight decrease in both types of cannibalism, although the reduction in cannibalism impact did not amount to more than a few percent. TRP treatment had no significant influence on the final survival of pikeperch post-larvae (ranged from 20.1 ± 12.4 to 29.0 ± 12.9 %). However, contrary to the earlier studies conducted on other fish species, no significant difference in the growth rates and feeding behavior of pikeperch between TRP-fed and control group were found. The final body weight and growth rate ranged from 0.211 ± 0.014 to 0.243 ± 0.016 and from 12.19 ± 0.38 to 12.76 ± 0.35 % day−1, respectively. To our knowledge, this is the first study reporting the effects of TRP supplementation on the cannibalism–survival–growth relations in fish in the post-larval stage.

Highlights

The fast growth and good nutritional value of the meat have contributed to the increase in interest in aquaculture of European percid fish species
Mortality caused by type II cannibalism significantly and negatively affected the final survival (r = -0.89; F = 41.21; P \ 0.05) contrary to mortality caused by type I which did not exert major impact on final survival (P [ 0.05)
The results of presently reported study confirmed that cannibalism was the main contributor to the mortality of pikeperch post-larvae, and the losses of type II cannibalism outnumbered those of type I cannibalism (Kestemont et al 2007; Szkudlarek and Zakes 2007; Szczepkowski et al 2011)

Summary

Introduction

The fast growth and good nutritional value of the meat have contributed to the increase in interest in aquaculture of European percid fish species. In farmed percid fish species, intra-cohort cannibalism, besides swim bladder inflation and non-feeding behavior, is an important factor that affects survival, especially during the early life stages of fish (Baras et al 2003; Kestemont et al 2003; Babiak et al 2004; Hamza et al 2007; Kestemont et al 2007; Mandiki et al 2007; Szkudlarek and Zakes 2007; Krol et al 2015). Intra-cohort cannibalism is mainly caused by size heterogeneity of larvae, which is usually affected by multiple interactive and non-interactive factors such as the environment and population structure, respectively (Kestemont et al 2003). Feeding the fish tryptophan-supplemented diet contributed to increasing levels of serotonin which tend to limit food intake and thereby resulted in depressed fish growth (De Pedro et al 1998; Hseu et al 2003; Papoutsoglou et al 2005a)

Objectives

Methods

Results

Conclusion