Effect of dietary essential amino acids addition on digestive enzime secretion in silver catfish Rhamdia quelen (Siluriformes, Pimelodidae) - DOI: 10.4025/actascibiolsci.v31i1.822

Abstract

Studies carried out with variation of protein concentration in the fish feed have shown an increase in the activity of alkaline proteases, acid proteases, trypsin and chimotrypsin from the digestive tract of silver catfish (Rhamdia quelen). These facts suggest that products released by digestion in the lumen of this tract can influenced the synthesis and secretion of digestive enzymes. The secretion of these enzymes by the pancreas in vertebrate responses to neural and humoral influences. In the present study, four concentration (0, 3, 6 and 12%) of an amino acid mix (threonine, phenylalanine, leucine, valine, arginine and thryptophan, in equal amounts) were tested in isocaloric (3500 Kcal of digestible energy/Kg of feed) and isoproteic (20% of protein) diets on juveniles of silver catfish. It was used 10 specimens per treatment stocked in a water recirculation system, with controlled and constant temperature. The fish submitted to the treatments presented alkaline activity in the anterior region of the gut, responding to the different levels of amino acid in the feed. Although there was alkaline proteases activity in the liver, the amylase activity of the liver and anterior gut was not observed.