Effect of dietary prebiotic fructooligosaccharide on histology, digestive enzyme activity, biochemical and immunological parameters of Asian seabass (Lates calcarifer) fingerlings

The aim of the study was to evaluate the effect of fructooligosaccharide (FOS) on histology, digestive enzyme activity,biochemical and immunological parameters of Asian seabass fingerlings with an average weight of 11.6 +/- 0.05 g. Experimental diets containing 0 (control), 0.25, 0.5, 0.75 and 1% FOS were prepared and the feeding experiment was carried out for a duration of 45 days. Analysis of biochemical parameters in the serum of post-fed animals revealed that glucose, urea, cholesterol, triglyceride, albumin, albumin globulin ratio (A/G ratio), aspartate aminotransferase (AST), alanine aminotransferase (ALT) and lactate dehydrogenase (LDH) showed significant differences (p<0.05) among the treatment diets. Similarly, serum immunological parameters such as alternative complement pathway and nitrobluetetrazolium assay showed significantly (p<0.05) higher activities in fishes fed with diets containing 0.75 and 1% FOS. Histological observation of post-fed experimental animals revealed increase in length and density of microvilli in the intestine and glycogen deposition in liver in FOS supplemented diets. The digestive enzyme activities were significantly (p<0.05) elevated with increasing levels of dietary FOS. The results indicated that supplementation of FOS at 1% modulates the intestinal and liver histology, digestive enzyme activities, biochemical and immunological parameters in Asian seabass.