Triguilho em dietas suplementadas com fitase para juvenis de jundiá Rhamdia quelen

Abstract

This study aimed to evaluate the productive performance, centesimal composition of the carcass, bone mineral composition and intestinal histomorphometry of juveniles of silver catfish Rhamdia quelen jundias fed diets with or without supplemented phytase. We used 288 juveniles with an average weight of 12.78 ± 2.78 g randomly distributed in 24 aquarium with useful volume of 500 liters in water recirculating system. During the period of 45 days the fish were fed four times a day with eight isoproteic and isocaloric diets constituted by 0; 33; 67 and 100% of replacement of corn by wheat middling supplemented with phytase (0 and 1,500 FTU kg-1). The experimental design was completely random in factorial scheme 4x2 (inclusion levels of wheat middling x phytase) with eight treatments and four replications, totalizing 24 experimental units. The zootechnical performance, carcass chemical composition, bone mineral composition and gut histology were evaluated. The data obtained were submitted to analysis of factorial variance (P<0.05) and when significates, the averages were submitted to Tukey test. For zootechnical performance, there was influence of the food in viscerosomatic fat index (P<0.05) where the replacement level of 100% showed lowest index. For carcass chemical composition, fish fed with wheat middling supplemented with phytase showed lowest levels of fat in carcass as well as fish fed with level of 100% without phytase. In the bone mineral composition, the replacement level of 100%, supplemented with the enzyme, showed the lowest values of calcium and manganese. For intestinal histology, differences were observed in fish fed the diet with 67%, without phytase, differ for the others treatments for height villi and total height of villi (P<0.05). The number of goblet cells did not present differences (P> 0.05). We can conclude that the wheat middling, independently of the enzymatic supplementation, can wholly replace corn in diets for the silver catfish without occurring zootechnical performance, carcass chemical composition, bone mineral composition and intestinal morphology damages.