Muscular Nutritional Components And Meat Quality Of Grass Carp (Ctenopharyngodon Idellus) Cultured Under The Model Of Cultivating Fish With Grass

This paper investigated the muscular nutritional components and meat quality of grass carp(Ctenopharyngodon idellus)in model of cultivating fish with grass.To study the effect of this culture model on the grass carp,we selected grass carps from two representative types of ponds applied in this model in central china,one is the “loop” like ponds in Honghu city and another one is common pond in the Chonghu Lake fishery.We studied the meat quality in this model and compared with the grass carps from common intensive culture ponds.The results provide basic data for ecological study on grass carp and healthy aquaculture in the future.In the experiment of grass carps from “loop” like ponds in Honghu city,the carps fed with grass(ecological grass carp,EGC)and fed with artificial feed(artificial feed grass carp,AFGC),16 individuals,respectively,were randomly selected to assay some indicators of meat quality.These indicators included water holding capacity and texture profiles parameters in muscle,contents of nutritional components,mineral elements,amino acids and fatty acids in muscle.The results showed no significant difference in hepatosomatic index and shell rate between EGC and AFGC.Significantly lower value in drop loss was observed in muscle of EGC compared with AFGC.No significant difference in flesh leaching loss,liquid loss and p H value.Hardness,springiness,cohesiveness,gumminess and resilience in muscle had no significant difference between EGC and AFGC.The content of crude fat in muscle of EGC was significantly lower than that of AFGC,while the contents of moisture,ash and crude protein in muscle had no significant difference.The contents of phosphorus(P)and iron(Fe)in muscle of EGC were significantly higher than that of AFGC.Additionally,the contents of magnesium(Mg),manganese(Mn)and chromium(Cr)in muscle of EGC were very significantly higher than that of AFGC.The compositions of amino acids were the same,containing17 amino acids,wherein the contents of essential amino acids in muscle were 6.85% and6.27%,respectively.The essential amino index(EAAI)of AFGC(EAAI was 77.29)was higher than that of EGC(EAAI was 76.07).The EGC and AFGC both contained 19 fatty acids,wherein the contents of palmitic acid,arachidonic acid(ARA),linoleic acid(LA),oleic acid,docosahexaenoic acid(DHA)and stearic acid were higher,as the main fatty acid.The contents of eicosapentanoic(EPA)plus DHA were 8.95% and 10.70%,respectively,and had significant difference.In the experiment of grass carps from common pond in the Chonghu Lake fishery,the grass carp in grass group(GCGG)and grass carp in feed group(GCFG),30 individuals,respectively,were randomly selected to assay some indicators of meat quality.These indicators included morphology indexes,color difference value of back skin,abdominal skin and muscle above lateral-line,blood biochemical indices,water holding capacity and shear force in muscle,contents of nutritional components,mineral elements,amino acids and fatty acids in muscle.The results showed that 1-2/body length and 4-9/body length of grass carp in GCGG were significantly higher than that of GCFG,4-5/body length,10-1/body length,2-10/body length and 5-7/body length in GCGG were very significantly higher than that of in GCFG,the left body proportions indexes all had no significant difference.The hepatosomatic index of grass carp in GCGG was very significantly lower than that of GCFG.And shell rate and fatness had not significant difference between GCGG and GCFG.The L value of back skin color,b value of abdominal skin color and muscle color above lateral-line of GCGG were very significantly higher than that of GCFG,yet a value of abdominal skin color and muscle color above lateral-line of GCGG were very significantly lower than that of GCFG.Others color difference value had no significant difference.Compared with GCFG,the serum content of glucose in GCGG was very significantly lower,yet serum activitie of alkaline phosphatase(ALP)in GCGG was significantly lower,and others indexes had no significant difference.The significantly lower value in drop loss and no significantly difference in flesh leaching loss were observed in muscle of GCGG compared with GCFG.The shear force in muscle of GCGG was very significantly higher than that of GCFG.Compared with GCFG,the content of moisture in muscle of GCGG was significantly higher,ash content was significantly higher,crude fat content was significantly lower,while crude protein content had no significant difference.The contents of phosphorus(Fe)and iron(Cr)in muscle of GCGG were significantly lower than that of GCFG,while content of magnesium(Zn),manganese(Mn)and chromium(Mg)had no significantly difference.The compositions of amino acids were the same in GCGG and GCFG,containing 17 amino acids,wherein the contents of essential amino acids in muscle were 6.88% and 7.04%,respectively.The essential amino index(EAAI)of GCFG(EEAI was 88.14)was lower than that of GCGG(EEAI was 84.78).GCGG and GCFG both contained 23 fatty acids,wherein the contents of oleic acid,linoleic acid(LA),palmitic acid,arachidonic acid(ARA),docosahexaenoic acid(DHA)and stearic acid were higher,as the main fatty acid.The contents of eicosapentanoic(EPA)plus DHA were 11.15% and 5.79%,respectively,and had significant difference.These results indicated that the morphology of grass carp fed with grass was more slender than grass carp fed with artificial feed.The grass carp fed with artificial feed had characteristics of better nutritional supply,faster growth than grass carp fed with grass,yet here were no difference in the health level.The muscle of grass carp fed with grass had characteristics of higher water-holding ability and lower fat content than that of grass carp fed with artificial feed.Therefore,during intensive feeding process of grass carp,it can significantly improve the meat quality of grass carp by feeding some proper forage.