Abstract:

Objective: To study the effect of dietary oxidized konjac glucomannan (OKGM) on growth performance,
blood lipid and lipid metabolism enzyme activities in Schizothorax prenanti Tchang (SPT). Methods: Three hundred
SPT with initial body weigh of (79.54 ± 8.12) g were randomly divided into 5 groups with 3 replicates of 20 fish in
each group. The feed for control group (D1) was free of OKGM, and that for treatment groups contained 4, 8, 16 and
32 g/kg OKGM, respectively. The experiment lasted for 60 days. Results: Compared with the control group, body
weight gain rate and specific growth rate were significantly improved by adding 8 g/kg and 16 g/kg OKGM in the
SPT diet (P ＜ 0.05). Addition of 16 g/kg OKGM in the SPT diet could significantly increase protein efficiency ratio,
and reduce feed conversion ratio and muscle moisture (P ＜ 0.05). Meanwhile, addition of 8 g/kg OKGM resulted in
a significant reduction in the fat content in muscle and hepatopancreas (P ＜ 0.05). In addition, addition of 4–16 g/kg
OKGM in the SPT diet significantly enhanced intraperitoneal fat ratio (P ＜ 0.05). Moreover, addition of OKGM in the
SPT diet affected the contents of total cholesterol, triglyceride, high-density lipoprotein cholesterol and low-density
lipoprotein cholesterol in serum without any dose-response relationship. OKGM addition at a dose of 4–8 g/kg in the
SPT diet could significantly decrease the content of free fatty acids. Furthermore, the activities of lipoprotein lipase,
hepatic lipase and total lipase were significantly increased by adding 16 g/kg OKGM (P ＜ 0.05). On the other hand,
the activity of intestinal lipase was significantly improved due to addition of OKGM at a dose of 8–32 g/kg (P ＜ 0.05).
Conclusion: Feed containing appropriate amounts of OKGM can improve the growth performance of SPT, increase the
feed conversion ratio, decrease muscle fat content, and improve the activities of lipid metabolism enzymes and lipase.
Meanwhile, OKGM at a dose of 4–16 g/kg is the optimal concentration in SPT feed.

Key words: oxidized konjac glucomannan, Schizothorax prenanti Tchang, growth, blood lipid, lipid metabolism enzyme activity