This study investigated the effects of dietary probiotic Saccharomyces cerevisiae in the striped catfish, Pangasianodon hypophthalmus, which is an important aquaculture species. Freeze-dried microencapsulated probiotic S. cerevisiae with guar gum was performed and used for fish feed supplementation. Striped catfish were fed for 120 days with one of three experimental diets: basal diet (control), basal diet supplemented with 106-CFU S. cerevisiae g-1 diet (S. cerevisiae 106), and basal diet supplemented with 108-CFU S. cerevisiae g-1 diet (S. cerevisiae 108). The S. cerevisiae-supplemented diets significantly improved growth performance including growth rate and feed conversion ratio over 120 days of culture period (P < 0.05). The rate of survival was similar in all experimental groups. Supplementation with S. cerevisiae did not significantly affect whole body proximate composition (P > 0.05). In addition, probiotic S. cerevisiae had no effects on hematological indices and blood chemistry values (glucose, cholesterol, triglycerides, protein, albumin, blood urea nitrogen, chloride, calcium, magnesium, iron, and phosphorus) (P > 0.05). However, dietary S. cerevisiae led to increases in humoral immune parameters including total immunoglobulin, lysozyme, and alternative complement activities (P < 0.05). Dietary S. cerevisiae led to increase intestinal villus height in the anterior part of intestine (P < 0.05). Taken together, while the dietary S. cerevisiae had no detectable effects on hematological indices and several metabolic indicators, significant beneficial probiotic effects were observed on rates of growth, feed conversion ratio, and immune parameters.
Keywords: Diet; Hematology; Immune; Intestinal morphology; Pangasianodon hypophthalmus; Probiotic; Saccharomyces cerevisiae; Striped catfish.