| Litopenaeus vannameiis one of the three majorcultured shrimps in the worldbecause of its fast growth rate,high flesh content,delicious taste and strong disease resistance.Macrobrachium rosenbergiiis one of the main freshwater shrimp in China because of its fast growth,less diseases,large body type and delicious taste.Researching on the muscle nutrients of Litopenaeus vannamei and Macrobrachium rosenbergii in different growth stagesfrom March to September 2017,Haifeng Aquaculture Professional Cooperative in Fengxian District,Shanghai,and Haocheng Aquaculture Professional Cooperative in Fengxian District,Shanghai from April to October 2018.The aims were to explore the nutritional value of shrimp muscles in different growth stages,and provided a theoretical reference for farmers to improve feed and shrimp quality during feeding.The Haifeng Aquaculture Cooperative mainly cultivated Litopenaeus vannamei,which was bred 2 times a year.The first carp(March-June 2017)was greenhouse farming,and the second carp(June-September 2017)was outdoor breeding,Haocheng Aquaculture Cooperative farmed Macrobrachium rosenbergii.After the shrimps were desalinated,the shrimp samples were collected every 20 days until the shrimps in the test ponds were arrested.The nutrients of the collected shrimp muscles were determined,including water,crude protein,crude fat,crude ash,amino acids and fatty acids,and the main results were as followed:1.Under the Greenhouse culture and outdoor culture mode,the contents of crude protein,crude fat and ash in shrimp muscles showed no obvious difference between Litopenaeus vannamei in similar growth phases.Considering the crude protein content,the Litopenaeus vannamei was more nutritious when grown for 40 d..Under the greenhouse culture mode,the unsaturated fatty acids of Litopenaeus vannamei at 40 d,60 d,74 d and 94 d accounted for 64.46%,60.97%,62.47% and 63.16% of the total fatty acid content,respectively.Under the outdoor culture mode,the unsaturated fatty acid contents of Litopenaeus vannamei at 40 d,60 d,80 d and 95 d accounted for 67.69%,64.74%,65.35% and 65.63% of the total fatty acid content,respectively.The muscles of Litopenaeus vannamei were rich in unsaturated fatty acids under the two cultivation modes,and the polyunsaturated fatty acids of Litopenaeus vannamei in the similar growth stage under the greenhouse cultivation mode were significantly lower than that in the outdoor cultivation mode.Considering the content of polyunsaturated fatty acids,both the greenhouse and the outdoor culture of the shrimps were more nutritious when the shrimps grew for 40 days.,and the outdoor culture was better than the greenhouse one.The amino acids composition in greenhouse cultured and outdoor cultured Litopenaeus vannameiin similar growth stages were consistent,which contained 17 kinds of amino acids.When Litopenaeus vannameigrew to 40 d,60 d,80 d and 95 d in the greenhouse culture mode,ΣEAA/ΣAA ratios were 29.36%,30.71%,33.28%,32.91% and ΣEAA/ΣNEAA ratios were 0.04%,55.63%,63.14%,60.56%.When Litopenaeus vannamei grew to 40 d,60 d,80 d and 95 d in the outdoor culture mode,ΣEAA/ΣAA ratios were 34.70%,33.69%,32.93%,34.11%,ΣEAA/ΣNEAA ratios were 64.44%,63.72%,62.66%,66.76%,which basically conformed to the FAO/WHO ideal model.The total amount of amino acids,essential amino acids and delicious amino acids in outdoor cultured Litopenaeus vannameiwere higher than that cultured in greenhouse.Conclusions were as followed: Greenhouse cultured and outdoor cultured Litopenaeus vannamei was a kind of shrimp which had high protein,low fat and high nutritional value.From the perspective of protein nutrition,the last growth phase of greenhouse cultured and outdoor cultured Litopenaeus vannamei had higher nutritional value,and the nutritional quality of outdoor cultured Litopenaeus vannamei was better than that of greenhouse cultured one.2.The contents of crude protein,crude fat and ash in muscles showed no obvious difference betweenMacrobrachium rosenbergii in different growth phases.From the crude protein content,the growth of Macrobrachium rosenbergii at 60 d was more nutritious..The total poly-unsaturated fatty acid contents of Macrobrachium rosenbergii at 61 d,81 d,102 d,123 d,143 d and 164 d accounted for 55.72%,54.68%,52.23%,49.48%,48.68% and 45.28% of the total fatty acid content,respectively;EPA+DHA contents of Macrobrachium rosenbergii accounted for 28.86%,29.17%,23.31%,21.26%,20.19% and 20.49% of the total fatty acid content,respectively,the contents gradually decreased with the growth of the shrimp.Considering the content of poly-unsaturated fatty acids,Macrobrachium rosenbergiiwas more nutritious when they grew for 61 days..The amino acids composition in Macrobrachium rosenbergii different growth stages were consistent,which contained 17 kinds of amino acids,and the highest glutamic acid content was obtained.When Macrobrachium rosenbergii grew to 61 d,81 d,102 d,123 d,143 d and 164 d,ΣEAA/ΣAA ratios were 32.87%,30.23%,32.76%,33.07%,33.77%,34.82% and ΣEAA/ΣNEAA ratios were 60.20%,54.01%,61.91%,63.40%,65.93%,69.57%,which basically conformed to the FAO/WHO ideal model.From the perspective of protein nutrition,the nutritional value of Macrobrachium rosenbergii growing from 102 d to 164 d was higher. |
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