Abstract:

Objective: To investigate the effects of water-soluble oxidized konjac glucomannan (OKGM) and water-insoluble
RS4-type resistant starch on growth performance, body composition and serum biochemical indices of Schizothorax prenanti
Tchang (SPT). Methods: A total of four hundred and fifty healthy SPT with average body weight of (87.58 ± 5.16) g were
randomly divided into 5 groups with each group including 3 replicates of 30 fish. The control group (C) was fed with a basal
diet without OKGM or RS4-type resistant starch, and the treatment groups OKGM1.6, OKGM3.2, RS41.6, and RS43.2 were fed
with the same basal diet supplemented with 1.6% and 3.2% of OKGM, and 1.6% and 3.2% of RS4-type resistant starch,
respectively. The experiment lasted for 60 days. Growth performance, body composition and serum biochemical indices
were measured. Results: Compared with the control group, the highest weight gain ratio (WGR), specific growth ratio (SGR)
and protein efficiency ratio (PER) and the lowest feed conversion ratio (FCR) were obtained by dietary supplementation with
1.6% OKGM (P < 0.05). These four paramers were not significantly changed by dietary RS4-type resistant starch. The FCR
was moderately reduced by dietary supplementation with 3.2% RS4-type resistant starch (P < 0.05). The crude protein content
of muscle was increased by adding OKGM to the diet. The crude lipid content of muscle and hepatopancreas were minimized
by 3.2% dietary OKGM (P < 0.05). The moisture and crude ash contents of muscle were not significantly affected by dietary
OKGM or RS4-type resistant starch (P > 0.05). The serum concentration of triglyceride was significantly decreased and serum
high density lipoprotein cholesterol (HDL-C) was significantly increased in OKGM1.6 group (P < 0.05). Similarly, the serum
concentrations of total cholesterol and triglyceride were significantly decreased and serum HDL-C was increased in RS43.2
group (P < 0.05). Conclusion: Dietary supplementation with 1.6% OKGM could ameliorate the growth performance of SPT,
increase the PER, decrease the levels of crude lipid in muscle and hepatopancreas, and regulate serum biochemical indexes.

Key words: Schizothorax prenanti Tchang, oxidized konjac glucomannan, RS4-type resistant starch, growth, body composition, serum biochemical indices