Suplementação de probiótico (Bacillus cereus e Bacillus subtilis) em dietas para Rhamdia quelen e seus efeitos no desenvolvimento reprodutivo e zootécnico

Abstract

Probiotic bacteria act in the host's intestine to balance the microbiota, triggering different effects directed to homeostasis. In this sense, studies related to the use of probiotic additive for silver catfish are extremely relevant for the productive development of native species. The objective was to evaluate the effect of probiotic additive (Bacillus subtilis and Bacillus cereus) in diets for silver catfish Rhamdia quelen on the productive performance, reproductive and physiological responses. 300 silver catfih juveniles with an average initial weight of 17.35 ± 0.97g were used, fed for 90 days with diets containing increasing levels of the probiotic additive (0.15; 0.30; 0.45 and 0.60 g. Kg-1 of feed of B. subtilis and B. cereus in concentrations of 4×1011 CFU) and a control diet. The experiment was divided into two stages, with trial 1: productive performance and trial 2: reproductive performance. In the productive performance, the centesimal composition, carcass yield, serum biochemical parameters and oxidative stress showed changes when using probiotics in diets. The development of the intestinal villi of the silver catfish was influenced by the inclusion of the probiotic additive in the diets, as well as the activity of mucus-secreting cells in the tissue. The growth of hepatocytes showed differences in terms of probiotic levels. In the evaluation of the reproductive development of fish, in males the additive influenced the relative seminal volume, sperm survival, gonadosomatic, hepatosomatic and viscerosomatic fat, frequency of transposed beating, displacement speed, motility rate and rectilinearity. In females, the use of probiotic influenced the proportion of spawning females, fertilization rate and viscerosomatic fat. The use of probiotic influenced the development of germ cells, liver integrity and development characteristics of hepatocytes. Therefore, the inclusion of 0.60g. kg-1 of probiotic in diets for silver catfish provides the development of fish, maximizing physiological processes, maintaining the health of animals and improving the productive and reproductive performance.