Effects Of Polysaccharose On Muscle Quality, Lipid Metabolism And Expression Of Heat Shock Protein 70 Gene Of Schizothorax Prenanti Tchang

Objective:The experiment conducted to investigate the effects of oxidized konjac glucomannan and resistant starch on growth, muscle quality, lipid metabolism and expression of heat shock protein 70 (HSP70) gene of Schizothorax prenanti Tchang, and aim at OKGM and RS4-type resistant starch provided the theory basic data for being reasonable application in aqutic feed.Methods:Five hundred and forty healthy Schizothorax Prenanti Tchang (SPT) with average body weight of (87.58±5.16) g were randomly divided into 6 groups and each group included 3 replicates of 30 fish. The control group (C) contained no OKGM and RS4-type resistant starch, and the treatment groups were contained 0.8%(OKGMo.s), 1.6%(OKGM1.6),3.2%(OKGM3.2) of OKGM and 1.6%(RS1.6),3.2%(RS3.2) RS4-type resistant starch respectively. The experiment lasted for 60 days. The food coefficient (FC), specific growth ratio (SGR), the body length and high, hepatopancreas somatic indices (HSI), condition factor (CF) and mesenteric lipid index were measured. The basic components of the muscle, amino acid and intensity of taste induction were measure. The activity of hepatopancreas lipoprotein lipase (LPL), hepatic lipase (HL), total lipase (TL) and lipase were measured. Expression of LPL mRNA, HL mRNA, sterols components binding protein 1c (SREBP-1c) mRNA, glucose-6-phosphate dehydrogenase (G6PD) mRNA, fat synthase (FAS) mRNA in hepatopancreas and HSP70 mRNA in spleen, head kidney and kidney were evaluated by real-time PCR of Schizothorax prenanti Tchang.Results:1. In terms of growth, compared to C group, the SGR increased while FC decreased by adding 1.6% OKGM in the SPT diet (P<0.05). The body length and high, HIS and CF were no significant difference by adding OKGM or RS in the SPT diet (P>0.05).2. In terms of muscle quality, compared to C group, the crude protein content increased in muscle (P<0.05), the crude fat content decreased in hepatopancreas by adding 1.6% or 3.2% OKGM in the SPT diet (P<0.05). The crude fat, moisture, crude ash, total amino acid, essential amino acid, amino acid and intensity of taste induction were no significant change in muscle by adding 1.6% or 3.2% OKGM in the SPT diet (P>0.05). The crude fat content decreased in hepatopancreas (P<0.05), the moisture, crude protein, crude ash, total amino acid, essential amino acid, amino acid and intensity of taste induction were no significant change in muscle by adding RS (P>0.05).3. In terms of fat metabolism enzymes in hepatopancreas, compared to C group, the LPL, HL, TL and lipase activity were enhanced by adding 1.6% OKGM in the SPT diet (P<0.05).4. In terms of expression of lipid metabolism related genes and HSP70 mRNA, compared to C group, the expression of LPL mRNA and HL mRNA were significantly up-regulated and the expression of G6PD mRNA was down-regulated in hepatopancreas (P<0.05) by adding 0.8% or 3.2% OKGM in the SPT diet (P<0.05). The expression of HSP70 mRNA was significantly down-regulated in spleen, head-kidney and kidney by adding 0.8% or 3.2% OKGM in the SPT diet (P<0.05). The expression of HL mRNA was up-regulated and the expression of HSP70 mRNA was down-regulated in spleen, head-kidney and kidney by adding RS in the SPT diet (P<0.05).Conclusion:Dietary addition of 1.6% OKGM could make for growth of SPT, reduce food coefficient, increase crude protein content in muscle, decrease crude fat content in hepatopancreas, enhance lipid metabolism enzymes activity, LPL and HL genes expression in hepatopancreas, down-regulate expression of G6PD gene and down-regulate expression of HSP70 gene in spleen, head-kidney and kidney. Therefore, adding 1.6% OKGM could promote SPT growth, regulate lipid metabolism and related genes, down-regulate expression of HSP70 mRNA.