Effects of the Dietary Tryptophan and Aspartate on the Immune Response of Meagre (Argyrosomus regius) after Stress

Abstract

Stress is one of the main problems of farmed fish, where it has been seen to result in a variety of disorders and negative effects. It is considered very important to minimize such effects and one option is the use of dietary additives. In the present experiment, meagre (Argyrosomus regius) specimens were fed three different diets: a control diet consisting of a commercial feed, a tryptophan-supplemented diet and an aspartate-supplemented diet. For each diet, fish were divided into three subgroups: non-stressed (resting), exposed to crowding or air-exposed. Just before the stress, and one and six hours post-stress, serum samples were taken to study several immune parameters (protease, antiprotease, peroxidase and lysozyme) and the bactericidal activity against three fish-pathogenic bacteria (Vibrio angillarum, V. harveyi and Photobacterium damselae subsp. piscicida). The results demonstrated that feeding the animals with the supplemented diets modulates the seric immune parameters, particularly when animals were stressed by air exposure.