Effects Of Two Kinds Of Breeding Systems On Feeding Habits And Meat Quality Of Procambarus Clarkii

In order to explore the effects of integrated rice-crayfish system(RCI)and crayfish monoculture system(CM)on the feeding habits and meat quality of Procambarus clarkii,and to understand the correlation between bait feed composition and meat quality,we conducted annual sampling of crayfish in the two systems respectively,and analyzed the seasonal variation and systematic difference of feeding habits of crayfish under the two breeding systems through stomach content analysis and biomarker fatty acid analysis.The seasonal variation and systematic difference of meat quality of crayfish under the two breeding systems were analyzed by abdomen meat percent,texture,nutritional composition,amino acids and fatty acids to find the optimal tasting period of crayfish.At the same time,we discussed the relationship between the feeding habits and meat quality of crayfish,and provided a theoretical basis for the healthy production of crayfish.The main research results and conclusions are as follows:The results of feeding habits analysis showed that:(1)In the stomach contents of crayfish,the food with the highest occurrence frequency was large plant fragments and organic detritus,with the average occurrence rates of 85.34% and 72.13%.(2)In the percentage of stomach contents,CM and RCI were the highest in plant tissues,which were 51.3%-85.4% and 53.1%-86.3%,respectively.Organic detritus followed,with9.9-43.6% and 7.9-32.4%.(3)The feeding rate and shannon-wiener index of crayfish were the highest in spring and the lowest in winter.In summer,the feeding rate of RCI was lower than CM,but the shannon-wiener index was higher than CM.(4)Biomarker fatty acids representing large plants had the highest contribution rate to bait composition,which ranged from 11.72% to 19.78%.Diatom and zooplankton followed,which were1.46%-15.23% and 2.33%-11.08%,respectively.The contribution rate of benthos fatty acids was the lowest,ranging from 0.19% to 2.43%.The results of meat quality analysis showed that:(1)The abdomen meat percent and meat crude fat of crayfish in May were significantly higher than those in other periods(P< 0.05),and the essential amino acid/non-essential amino acid(EAA/NEAA)was the maximum,which were 66.49 and 67.56 respectively,and there were no significant differences in other indexes(P > 0.05).The meat hardness,springiness and chewiness of crayfish in March were significantly lower than those in other periods(P<0.05),and the delicious amino acid/total amino acid(DAA/TAA),eicosapentaenoic acid(EPA),arachidonic acid(ARA)and docosahexaenoic acid(DHA)were reached maximum.(2)From the system analysis,the meat crude protein content and EAA/NEAA of crayfish in RCI were 0.20%-0.43% and 0.11-0.20 higher than those of crayfish in CM in March and May,respectively,and there was no obvious rule in the meat water holding capacity,p H and texture indexes.The meat crude protein content and EAA/NEAA of crayfish in RCI were 0.14%-1.09% and 0.03-0.05 lower than those of crayfish in CM in July and September,respectively.(3)The correlation analysis between the bait composition and meat quality showed that the bait composition could affect the meat fatty acid content,and the feeding rate was significantly positively correlated with the crude protein,hardness and abdomen meat percent(P < 0.05).In conclusion,crayfish preferred to feed on large plant tissues and organic detritus,and had the highest diet diversity and feeding rate in spring and the lowest in winter.The fatty acid content of meat was affected by different bait composition,and the feeding rate was positively correlated with abdomen meat percent,crude protein and hardness(P <0.05).The meat quality of crayfish in May was the best,and the meat quality of RCI group in March and May was better than that of CM group.The meat quality of RCI group decreased in July and September,while the meat quality of CM group was stable.