Innate immune response of pirarucu improved with yeast-supplemented diets

Abstract The present study evaluated the effects of dietary yeast supplementation on the growth and blood parameters of Arapaima gigas. Fish were fed with commercial feed supplemented with NuPro® at 0, 10, 40 and 80 g / kg for 30 days and, did not exhibit any difference in growth. Blood was analyzed at the end of the feeding trial and after handling stress. A significant reduction in albumin and triglycerides levels was observed with increased supplementation of NuPro® in the diet of A. gigas. The interactive effect of diet and stress influenced plasma glucose levels, with a modulation at all levels of supplementation after stress, while in the control group the level was significantly high. NuPro® improved the innate immune response of A. gigas at all the tested concentrations, with a significantly higher levels number of thrombocytes, leukocytes, lymphocytes, monocytes, and neutrophils than the control group. There was also an increase in the number of thrombocytes after stress. As the inclusion of NuPro® in the diet improved the innate immune response at all the concentrations tested and effectively modulated plasma glucose levels, this product can be recommended as an immunostimulant for A. gigas fingerlings with the inclusion of 40 g/kg of feed.