Probiotic effects (<i>Bacillus cereus</i>and<i>Bacillus subtilis</i>) on growth and physiological parameters of silver catfish (<i>Rhamdia quelen</i>)

Abstract

This study aimed at evaluating the effects of a probiotic additive in productive performance and physiological parameters for Rhamdia quelen. The fish were fed diets containing increasing levels of the additive (0.15; 0.30; 0.45; and 0.60 g/kg of feed), which consisted of a blend of Bacillus cereus and B. subtilis, both at the concentration of 4 × 1011 CFU). Productive performance parameters were higher in fish fed diets containing 0.60 g/kg of the probiotics. Both the proximate composition and carcass yield were affected when 0.30 and 0.60 g/kg of the additive was included, whilst serum biochemical parameters were higher in fish fed diets containing 0.60 g/kg of the additive. An increase in the hepatic oxidative stress activity was found when 0.30 g/kg was supplied. The development of intestinal villi was influenced by the inclusion of the additives, as well as the activity of mucous-secreting cells in the tissue. Hepatocyte's growth was differential in fish fed diets containing 0.30 g/kg and other tissue alterations were found using 0.60 g/kg of the additive. The inclusion of 0.60 g/kg of the probiotic in diets for R. quelen enhances its growth performance and physiological status.