Effects Of Dietary Fermentation Products Of Table Leftovers On Growth Performance,Muscle Quality,Immune Enzyme Activity And Digestive Function Of Procambarus Clarkii

In order to investigate the feasibility of the application of table leftovers in the feed of Procambarus clarkii,we added 0%(control group),3%,6% and 9%proportions of fermentation products of table leftovers into the basic feed,respectively,and made four groups of iso-nitrogen and lipid feeds in this study.A 30-day culture experiment was conducted on Procambarus clarkii in cage and pond mode to explore the effects of fermentation products of table leftovers on growth performance,muscle quality,immune enzyme activity and digestive function of Procambarus clarkii,and to comprehensively evaluate the effect and application value of fermentation products of table leftovers.The main research results and conclusions are as follows:1.Cage culture experiment.(1)Feeding diets containing fermentation products of table leftovers for 30 days had no significant effects on weight gain rate,hepatosomatic index,meat yield and specific growth rate of crayfish(P>0.05),but significantly increased survival rate,total output and total weight gain rate,and significantly decreased feed conversion ratio(P<0.05).The total output and total weight gain rate of 6% added group were the highest,which were increased by 52.70% and 108.51% compared with control group,respectively.(2)Fermentation products of table leftovers had no significant effects on the contents of crude protein and ash in the muscle of crayfish(P>0.05),but significantly increased muscle springiness(P<0.05).The crude fat content in 3% and6% added groups were significantly decreased by 12.61% and 13.77% compared with control group(P<0.05).The content of 4 main delicious amino acids in the muscle of9% added group was significantly lower than that of control group and 3% added group(P<0.05).(3)The activities of serum alkaline phosphatase(AKP),acid phosphatase(ACP)and lysozyme(LZM)in 6% added group were significantly increased at the 15 d(P<0.05).At the 30 d,the activities of serum superoxide dismutase(SOD)and catalase(CAT)in 6% added group were significantly decreased by 14.88% and 39.50%,while AKP,ACP and LZM activities were significantly increased by 76.56%,65.28% and 172.42% compared with control group,and LZM activity in 6% added group was significantly higher than that in 3% and 9% added groups(P<0.05).(4)The hepatopancreatic lipase(LPS)activity in 3% and 6% added groups were significantly higher than that in control group at the 15 d(P<0.05).At the30 d,the LPS activity in 3% added group was significantly higher than that in the other three groups,and the amylase(AMS)activity in fermentation products added groups were all significantly higher than that in control group(P<0.05).Histological observation showed that the morphology of hepatopancreas was better in 6% added group,which contained abundant R 、 E 、 F cells,and the intestinal tissue of 6%added group was the most complete.In addition,due to the high crude fat content of the fermentation products of table leftovers in this experiment,the more difficult it is to granulate the feed with the increase of the adding proportion,and 9% is the highest adding proportion.In conclusion,under the conditions of this experiment,fermentation products of table leftovers can be used in the diet of Procambarus clarkii and the suitable adding level is 6%.In this case,the survival rate of Procambarus clarkii is increased while the feed conversion ratio is decreased,which can obtain the better total output and total weight gain rate.Meanwhile,the muscle quality,immunity and digestive function are improved overall,and the comprehensive benefit is the best.2.Pond culture experiment with the purpose of verifying the effect of fermentation products of table leftovers.In the pond experiment,weight gain rate,hepatosomatic index and specific growth rate of crayfish in 9% added group were the largest after 30 days of feeding,which had significant differences with 3% added group(P<0.05).The meat yield of6% added group was the highest,and there was no significant difference in growth indexes between 6% added group and the other two groups(P>0.05).When the proportion of fermentation products of table leftovers was 6%,ΣDAA reached the maximum value in muscle,while total essential amino acid(ΣEAA)and total essential amino acid/total non-essential amino acid(ΣEAA/ΣNEAA)were the highest in 9% added group.There were no significant differences in muscle texture indexes among all groups(P>0.05).After the addition of 9% fermentation products of table leftovers,the activity of LZM,which was the most active enzyme in the serum of crayfish,was decreased dramatically,and the activities of amylase and trypsin in hepatopancreas were the lowest,while the intestinal tissue structure defects were found.Compared with the cage mode,the crude fat content and ΣDAA in the muscle of crayfish were higher in the pond mode,and the muscle hardness,gumminess and chewiness were increased.In general,the growth performance of crayfish was better and the muscle protein quality was higher with the addition of 9% fermentation products of table leftovers,but the delicious degree was poor,and the immune capacity and digestive function were decreased generally.The flavor and taste of crayfish in each group were better than those in the cage mode,while the edible nutritional value was slightly lower than that in the cage mode.Considering the granulation factor of feed in practical application,it is suggested to add 6%fermentation products of table leftovers into the feed of Procambarus clarkii to obtain the best comprehensive effect.