Suplementação de glutamina para tilális do Nilo (Oreochromis niloticus) alimentadas com rações com substituição de milho por farelo de algaroba (prosopis juliflora)

Abstract

The growth in the aquaculture sector stimulates research in the utilization of alternative feed, as mesquite (Prosopis juliflora) meal, which in many occasions have the presence of anitnutritional factors (ANF) that jeopardize the performance and the gastrointestinal tract. Glutamine is notorious for presenting the capacity to stimulate the growth and to restore the tract. Thus, the aim of this study was to evaluate if glutamine is capable of neutralize the undesired effects of ANF. It was utilized 264 Nile tilapia (Oreochromis niloticus) with initial weight of 37,85 ± 3,75 g, divided in 12 tanks with 100 L capacity. The experimental diets were composed of: CD – control diet, MD – diet with the substitution of 30% of corn by mesquite meal, and MGD – diet with the substitution of 30% of corn by mesquite meal and addition of 1.2% of glutamine. It was evaluated the zootechnical performance, hematological and biochemical blood parameters, enzymatic activity, centesimal composition of carcass, and histomorphometric analysis. For zootechnical performance parameters, it was observed that the supplementation of glutamine the fish of diet MGD was capable of obtaining a statistically similar performance as the fish from the CD. Regarding the carcass composition, it could be observed that mesquite was responsible for increasing the humidity, crude protein, and mineral matter levels, for ethereal extract it was lower in the diets with the presence of mesquite. Enzymatic, hematological and biochemical blood data showed that mesquite decreased the activity of AST, increased the blood glucose concentration, while glutamine decreased the activity of sucrose and the HDL concentration in the blood. Histomorphometric analysis showed that glutamine was responsible for increasing both villus height and apex epithelium thickness, even with the substitution of corn by mesquite. In this manner, glutamine influenced positively the performance of the animals, because of the improvement in the gastrointestinal tract by means of the villus height increase, besides glutamine is an amino acid important in proteic synthesis, enterocytes proliferation, and it is intimately related to the energetic metabolism, through the conversion of glutamine to glutamate. It can be concluded that the supplementation of 1.2% of glutamine was capable of neutralize the undesirable effects of ANF present in the mesquite meal.