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

摘要

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 A degrees 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 +/- A 12.4 to 29.0 +/- A 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 +/- A 0.014 to 0.243 +/- A 0.016 and from 12.19 +/- A 0.38 to 12.76 +/- A 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.