| The experiment was conducted to investigate the effects of low molecular weight oxidized konjac glucomannan and oxidized konjac glucomannan sulfate on growth, visceral index, Serum immune and antioxidant index, expression of immune related genes, aimed to provide theory basic data for reasonable application of LOKGM and OKGMS in functional food. Four hundred and twenty healthy Schizothorax prenanti with average body weight of (81.00±2.48 g) were divided into 7 groups randomly and each group included 3 replicates. The control group contained no LOKGM and OKGMS, the treatment groups were contained 0.4%、0.8%、1.6% of LOKGM and OKGMS respectively. After feeding 60 d, the specific growth ratio, condition factor, mesonephros index, head kidney index, spleen index, liver index, intestinal weight index and intestinal length index were measured. The activity of lysozyme (LZM), the alternative complement pathway activity (ACH50), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and the content of immunoglobulin M (IgM), malondialdehyde (MDA) in serum were measured according to the kit instructions. Expression of toll-like receptor 22 (tlr22) mRNA, myeloid differentiation factor88 (myd88) mRNA, interferon regulatory factor 7 (irf7) mRNA, tape Ⅰ interferon (I-ifn) mRNA, transforming growth factor-β1 (tgf-β1) mRNA in head kidney, mesonephros, gut, liver, and spleen were evaluated by real-time PCR.The results are as follows:1. In terms of growth and viscera index, there was no significant difference in specific growth ratio (p>0.05), condition factor, mesonephros index, head kidney index, liver index, intestinal weight index and intestinal length index, the spleen index of fish fed OKGMS1.6 was significantly higher than that of fish fed the basal diet (p<0.05).2. In terms of serum antioxidant indicators, the serum SOD activity of fish fed OKGMS and LOKGM was increased and each dose groups of OKGMS reached significant level (p<0.05); The serum MDA content of fish fed OKGMS0.4、OKGMS0.8、 LOKGM0.4, LOKGM0.8 was significantly lower than that in control group (p<0.05), illustrate that the OKGMS and LOKGM has a certain influence on the content of serum MDA; The serum GSH-PX content of fish fed LOKGM0.8、LOKGM1.6 was significantly higher than the control group (p<0.05) and there was no significant difference in other groups.3. In terms of serum immune indicators, compared to the control group, the IgM activity and ACH50 content of fish fed OKGMS1.6 was significantly increased (p<0.05), other groups can improve the content of serum IgM, but did not reach significant level; the LZM activity of fish fed OKGMS1.6 and LOKGM0.8 was higher than that of fish fed the basal diet (p<0.05).4. In terms of primer design and validation, the partial cDNA fragment of tlr22, myd88, irf7,1-ifn and tgf-β1 had been cloned refer to immune related gene sequences of bream such as carp, zebrafish, grass carp, and the length of the fragments was 174bp、 125bp、142bp、192bp and 190bp, encoding 58,41,47,64 and 63 amino acids respectively. The tlr22, myd88, irf7,I-ifn and tgf-β1 gene was highly similarity to amino acid sequence and genetic relationship of bream from the amino acid sequence alignment analysis results and the evolutionary tree.5. In terms of expression of immune related genes, the expression of tlr22 mRNA was significantly up-regulated in head kidney, mesonephros, gut and liver by adding OKGMS (p<0.05), but there was no significant difference in spleen (p>0.05), dietary LOKGM could increase the expression of tlr22 mRNA in head kidney, mesonephros, gut, liver and spleen (p<0.05); OKGMS could significantly up-regulate the expression of myd88 mRNA in mesonephros, gut and liver (p<0.05), but there was no significant difference in head kidney and spleen (p>0.05), LOKGM could increase the expression of myd88 mRNA in head kidney and gut (p<0.05), but there was no significant difference in mesonephros, liver and spleen (p>0.05); The expression of irf7 mRNA was significantly increased in mesonephros, liver and spleen by adding OKGMS (p<0.05), but there was no significant difference in head kidney and gut (p>0.05), LOKGM could significantly increase the expression of irf7 mRNA in gut, liver and spleen (p<0.05), with no significant difference in head kidney and mesonephros (p>0.05); OKGMS has no significant influence on the expression of I-ifn mRNA in head kidney (p>0.05), but increased the expression of I-ifn mRNA in mesonephros, gut, liver and spleen (p<0.05), LOKGM could up-regulate the expression of I-ifn mRNA in mesonephros, gut and spleen (p<0.05), but there was no significant difference in head kidney and liver (p>0.05); The expression of tgf-β1 mRNA was significantly reduced in head kidney, gut and liver by adding OKGMS (p<0.05), but there was no significant difference in mesonephros and spleen (p>0.05), LOKGM could significantly down-regulate the expression of tgf-β1 mRNA in head kidney, mesonephros, and liver (p<0.05), with no significant difference in gut and spleen (p>0.05).Therefore, we can draw the following conclusions:Dietary addition of OKGMS and LOKGM have little influence on growth and visceral index of Schizothorax prenanti, only OKGMS1.6 significantly increased spleen index; OKGMS have significant influence on the serum SOD activity of Schizothorax prenanti; Low dose and middle dose of OKGMS and LOKGM significantly decreased serum MDA content of Schizothorax prenanti compared with the control group; LOKGM0.8、LOKGM1.6 have significantly influence on the GSH-Px content of serum; Dietary addition of OKGMS and LOKGM could up-regulate the expression of tlr22、 myd88、irf7、I-ifn mRNA in head kidney, mesonephros, gut, liver and spleen and down-regulate the expression of tgf-β1 mRNA, LOKGM0.8 and OKGMS0.4 were more prominent than other groups. |
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