Effect of dietary oxidized konjac glucomannan on Schizothorax prenanti growth performance, body composition, intestinal morphology and intestinal microflora

The aim of the present study was to examine the effect of oxidized konjac glucomannan (OKGM) on Schizothorax prenanti growth performance, body composition, intestinal morphology and intestinal microflora. Fish were fed a basal diet or basal diet plus 4.0, 8.0, 16.0 and 32.0 g kg−1 OKGM for 60 days. The results indicated that WGR and SGR were significantly higher in fish fed 8.0 and 16.0 g kg−1 OKGM diets (P < 0.05) than those in fish fed basal diet, and PER was significantly higher and FCR was significantly lower in fish fed 16.0 g kg−1 OKGM diet (P < 0.05). The content of body protein, lipid and moisture was affected by the OKGM diets. The light and electron microscopy demonstrated that intestinal morphology of fish fed 8.0 and 16.0 g kg−1 OKGM diet was better (P < 0.05) than the control group, including mucosa fold height, mucosal epithelial height, submucosa height, longitudinal muscularis thickness and circular muscularis thickness. Compared with the control group, fish fed 32.0 g kg−1 OKGM diet showed significantly lower goblet cell number in anterior intestine (P < 0.05). Furthermore, intestinal microflora was analyzed by PCR-DGGE, and the results showed that OKGM diets also significantly modulated the intestinal microflora of fish (P < 0.05). The study clearly demonstrates that OKGM could enhance the growth performance, improve intestinal morphology and modulate intestinal microflora of S. prenanti, and the optimal dietary OKGM levels was suggested to be 16.0 g kg−1.