| The swimming crab is a very important fishery and aquaculture species in east Asian，the livingindividual and its processed products both have high nutritional value. the industry is the pillarPortunidae industries of fisheries in the world. It had rich nutrient and unique taste, so it be loved bylots of people. But there are some problems in swimming crab industry, such as: market time of crabsupplying the is shorter and more concentrated, and the type of deep processing of crab products isvery limited, there is a need to develop the deep-processed products; Asians eating hepatopancreasovarian, while Europe and the United States only eat the muscle.Therefore, deep processing ofproducts should be classified according to the needs of the market, while there is rare relevant reportsabout the swimming crab’s the nutritional quality of different parts; swimming crab supply isdependent on capture fisheries, but to bring the consequences of resource exhaust, ecologicaldamaged. In order to solve this problem, we should rely on the aquaculture individual to meet theneeds of the market; but,as to the pond reared swimming crab’s goods crab, the proportion ofhigh-quality crab is quite less, therefore, should explore reasonable means of fattening, crab quality ofgoods improved to meet market demand.In this study, we focus on the quality and the fattening time on that and conducted two experiment:Experiment1: COMPARISION OF NUTRITIONAL QUALITY OF DIFFERENT MUSCLEPARTS OF PORTUNUS TRIBERCULATUS:The swimming crab is a very important fishery andaquaculture species in east Asian. The present study was conducted to compare the meat quality ofdifferent part, i.e abdomen, claw and leg, based on proximate composition, amino acid, lipid class,fatty acid, collagen content and cross-sectional area of muscle fiber. The results showed that:(1)abdomen meat is largest part of all edible yields, accounted for16.88±2.94%. Although nosignificant differences could be found on moisture, ash and total carbohydrate of three parts, legmeat contained significant higher total lipids than claw (P<0.05) and lower crude protein thanabdomen(P<0.05).(2) The Ile, Leu, Lys, Tyr, Glu and Gly contents were higher in the claw meatthan in the leg meat(P<0.05), while abdomen meat had the highest Pro content among threeparts(P<0.05).(3) The claw meat had the least FFA comparing other parts (P<0.05), while leg meathad the least TG. Thirty-one fatty acids were found in the meat of three parts, C14:0，C15:0，C18:0，C16:1n7，C20:2n6，C20:3n3and C22:6n3contents showed little difference among three parts. Allmeat parts had high ARA(6.10~6.79%), EPA(14.63~15.70%), DHA(13.42~15.52%) percentage,which indicate lipid composition of this crab is healthy and balanced for human consumption.(4)Although no significant difference could be found on the collagen contents of three parts, the biggestaverage cross-sectional area of muscle fiber could be found on the claw among three parts, and leghad the smallest of that. In conclusion, both parts are high nutrition food, but the leg meat is moretender than the abdomen and claw. Experiment2: The effect of fattening time on nutrition quality of swimming crab, Portunustrituberculatus: Swimming crab is a very important commercial crab species with high nutritionvalue,however,high quality commercial crabs is hard to get through the present culturetechnique.Therefore,it is quite crucial to find out condition of culture high quality commercialcrabs.In this study,swimming crabs were fed by live constricted tagelus(Sinonovacula constricta) for30days,60days and90days to study the effect of fattening days on the quality of swimmingcrab.The result showed that(1) the effect of fattening days on weight and hepatosomatic index(HSI)were not significant,however,it affected the gonadosomatic index(GSI), meat yield and total edibleyield(p<0.05).With days increasing,the GSI grew dramatically,from0.52%to7.52%,while the meatyield and total edible yield decreased(p<0.05).(2)The moisture, crude protein and crude lipidcontent in hepatopancreas and muscle showed no significant difference among different days, butfattening days could increase the crude protein and crude lipid content in the ovary.(3) Fatteningdays took a little effect on fatty acids content in hepatopancreas,only c15:0,c16:0and c18:1n7decrease with days increasing;however,the fatty acids content in ovary and muscle among differentdays displayed significant difference.Although the SFA in ovary and muscle decreased with daysincreasing,the PUFA and HUFA increased significantly.(4)Besides,the fattening days could decreasethe collagen content of crab meat and increase the average cross-sectional area of muscle fibre. Inconclusion, fattening days affect the quality of swimming crab actually:the biggest total edible yieldand the highest collagen content of crab meat was found in30days,and the biggest GSI and the bestovary quality was observed in90days.on the basis of the above results,then two experiments were conducted: swimming crabs wasfeed on the diet contained DHA/EPA and HUFA and evaluated its nutritional quality, the resultsshow that when DHA/EPA=2,the best developed ovary and highest hepatopancreas index（HSI）were founded; when DHA/EPA=1, n3/n6ratio of the muscle was the largest. And when HUFAcontent is too high, HIS and GSI will be reduced, and the white liver rate increased, indicating thattoo much HUFA may be a negative factor to swimming crab.. |
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