Effects Of Soybean Antigen Protein Glycinin On Growth Performance,Antioxidant Capacity And Intestinal Tissue Of Golden Crucian Carp,Cyprinus Carpio×Carassius Auratus

Soybean meal(SBM)is one of the most promising plant pro tein sources to replace fishmeal because of its high protein content,balanced amino acids and low price.However,the high proportion of SBM to replace fish meal will have a negative impact on animals.These negative effects are partly due to the existence of anti-nutritional factors in SBM.Among them,the glycinin is one of the most immunogenic proteins in soybean anti-nutritional factors and has strong sensitization.Therefore,the study was designed to examine the effects of glycinin on growth,antioxidant capacity and intestinal tissue of golden crucian carp [initial body weight(4.88±0.04)g/tail].Five isonitrogenous and isolipidic diets were produced which containing glycinin at 0,30,60,90,and 120 g/kg,respectively.And fish were fed these diets for 8 weeks.The study provided a theoretical basis for the rational development and utilization of soybean protein sources and healthy and efficient breeding of golden crucian carp.1.Effects of soybean antigen protein glycinin on the growth performance and expression of IGF-I of golden crucian carpWith the increase of soybean antigen protein glycinin content in diets,the final body weight(FBW),weight gain(WG),specific growth rate(SGR),feed efficiency rate(FER)and protein efficiency rate(PER)of golden crucian carp were showing a downward trend.The FBW,WG,SGR,FER and PER of D-3,D-6,D-9 and D-12 groups were significantly lower than those of the control group(P<0.05).While,soybean antigen protein glycinin had no significant effect on hepatosomatic index(HSI),viscerasomatic index(VSI),condition factor(CF),and survival rate(SR)of golden crucian carp(P>0.05).Under the test conditions,the crude protein of the muscle of golden crucian carp showed a downward trend with the increase of soybean antigen protein glycinin.Among them,the D-6,D-9 and D-12 groups were significantly lower than the control group(P<0.05),but the D-3 group had no significant effect compare with the control group(P<0.05).Soybean antigen protein glycinin had no significant effect on the moisture,crude fat and crude ash in the muscle of golden crucian carp(P>0.05).The m RNA levels of IGF-I in hepatopancreas of fish were significantly decreased by glycinin(P<0.05).And compared with the control group,the m RNA levels of IGF-I in hepatopancreas of fish were significantly decreased in the group of D-3,D-6,D-9 and D-12(P<0.05).2.Effects of soybean antigen protein glycinin on the activities of digestive enzymes and protein metabolizing enzymes of golden crucian carpThe protease activity in hepatopancreas,proximal intestine(PI),mid intestine(MI)and distal intestine(DI)of golden crucian carp showed a downward trend with the increase of soybean antigen protein glycinin.Compared with the control group,the protease activity in PI and MI of fish were significantly decreased in the group of D-3,D-6,D-9 and D-12(P<0.05);and the protease activity in hepatopancreas and DI of fish were significantly decreased in the group of D-6,D-9 and D-12(P<0.05);there were no significant differences on the activities of lipase and amylase of the hepatopancreas and intestine of glycinin treatment groups(P>0.05).Compared with the control group,glutamic oxalacetic transaminase activity in hepatopancreas in D-12 group was significantly decreased(P<0.05),but there were no significant effects in D-3,D-6 and D-9 groups(P>0.05).Glumtaic pyruvic transaminase activity in hepatopancreas in the group of D-6,D-9 and D-12 group were significantly decreased(P<0.05),but there was no significant effects in D-3 groups(P>0.05).3.Effects of soybean antigen protein glycinin on non-specific immune indexes of golden crucian carpIn this study,the activities of lysozyme(LZM),alkaline phosphatase(AKP)and acid phosphatase(ACP)in hepatopancreas of golden crucian carp showed a downward trend with the increase of soybean antigen protein glycinin.The results showed that compared with the control group,the AKP and LZM activities of fish were significantly decreased in the group of D-3,D-6,D-9 and D-12(P<0.05);ACP activities were significantly decreased in D-9 and D-12 group(P<0.05),but there were no significant effects in D-3 and D-6 groups(P>0.05).4.Effects of soybean antigen protein glycinin on antioxidant capacity of golden crucian carpUnder the test conditions,with the increase of soybean antigen protein glycinin content in diets,the malondialdehyde(MDA)content in hepatopancreas and intestine of golden crucian carp showed upward trend.Compared with the control group,the MDA content in the PI and DI of fish were significantly increased in D-3,D-6,D-9 and D-12 group(P<0.05);Nevertheless,the MDA content in the hepatopancreas and DI of fish were significantly increased in the group of D-6,D-9 and D-12(P<0.05).The total antioxidant capacity(T-AOC)and the activities of catalase(CAT),glutathione peroxidase(GPx)and total superoxide dismutase(T-SOD)in hepatopancreas and intestine of golden crucian carp showed a downward trend with the increase of soybean antigen protein glycinin.Compared with the control group,T-AOC content in MI and DI,the CAT activity of the PI,MI and DI,the GPx activity in the DI,the T-SOD activity in the DI and hepatopancreas of the groups of D-3,D-6,D-9,and D-12 were significantly decreased(P<0.05);The CAT activity in hepatopancreas,the GPx activity in PI,MI and hepatopancreas,T-SOD activity in PI and MI of D-6,D-9 and D-12 groups were significantly decreased(P<0.05);The T-AOC in PI and hepatopancreas of D-9 and D-12 groups were significantly decreased(P<0.05).5.Effects of soybean antigen protein glycinin on intestinal tissue of golden crucian carpThe intestinal weight,MI fold height and DI fold height of golden crucian carp in D-3,D-6,D-9 and D-12 groups were significantly decreased compare with control group(P <0.05).Compared with the control group,the intestinal length of golden crucian carp in D-9 and D-12 groups were significantly decreased(P<0.05),but there was no significant effects in D-3 and D-6 groups(P>0.05).The PI fold height of golden crucian carp in the D-6,D-9 and D-12 groups were significantly decreased compare with control group(P<0.05),but there was no significant effects in D-3 groups(P>0.05).Soybean antigen protein glycinin had no significant effect on the intestinal body index and intestinal length index of golden crucian carp(P>0.05).In the control group,the structure of the PI,MI and DI of the golden crucian carp were clear and complete,the intestinal villi were well developed,the striated margins were arranged neatly,the muscular layer was thick,and the serosa was intact.The lamina propriae of the PI,MI and DI began to separate and the intestinal villi were broken in the D-3 group.In the D-6,D-9,and D-12 groups,the damage to the PI,MI and DI morphology of the golden crucian carp aggravated,and the intestinal cells separated from the propria and aggravated and severely atrophied.In summary,the content of soybean antigen protein glycinin in compound feed of the golden crucian carp should not exceed 30 g/kg.