Tambaqui responses to stress due to transport after feeding with b-glucan supplemented diets

This study aimed to evaluate the physiological responses to stress of tambaquis (Colossoma macropomum) fed with β-glucan supplemented diet undergoing transportation in a closed system. To do so, tambaquis (35.06±0.80g; 11.8±0.09cm) were fed with a β-glucan supplemented diet (0; 0.1; 0.2; 0.4; and 0.8%.kg-1) for 60 days. After this period, fishes were transported on road for 3h in a closed system. Responses to stress were evaluated through hormonal, biochemical, and hematological indicators within the following periods: before transportation, immediately after transportation, and 24 and 48h after transportation. Immediately after transportation, there was a significant increase in the plasma concentrations of cortisol and glucose in all treatments when compared to the concentration before transportation; there was an increase in the hemoglobin concentration in fishes fed without a b-glucan supplementation diet; and there was an increase in the mean corpuscular hemoglobin in fishes fed without supplementation or supplemented with 0.1 and 0.2% of b-glucan. The results allowed us to establish that the hormonal, biochemical, and hematological changes occurred immediately after transportation, with return to the basal concentrations after 24h. β-glucan supplementation in the tambaqui diet wasn’t effective to relieve the responses to stress due to transport.