不同家系大黄鱼肌肉营养成分的比较

Comparison of biochemical compositions of muscle among three stocks and wild-caught large yellow croaker Pseudosciaena crocea

对同等养殖条件下所养成的大黄鱼[Pseudosciaena crocea(Richardson)]3个不同家系:WW家系[野生F1(♀)×野生F1(♂)]、WC家系[野生F1(♀)×养殖F8(♂)]和CC家系[养殖F8(♀)×养殖F8(♂)]成鱼肌肉营养成分进行测定,并以野生大黄鱼作为对照,从营养成分的角度分析和评价不同家系大黄鱼的品质。结果显示,野生大黄鱼粗蛋白含量、必需氨基酸以及鲜味氨基酸总量都明显高于家系大黄鱼,而必需脂肪酸含量则低于家系大黄鱼。3个家系之间,粗蛋白质含量、必需氨基酸总量、鲜味氨基酸总量及必需氨基酸指数排列次序由大到小依次为:WW、WC、CC;饱和脂肪酸总量由大到小的排序为:CC、WW、WC;不饱和脂肪酸总量由大到小依次为:WC、WW、CC。研究认为,家系之间主要营养成分指标存在一定差异,这是由遗传因素决定的,因此通过家系选择进行大黄鱼肉质改良是可能的,但是同时必须结合饲料营养成分的补充和调控以及养殖环境条件的改善,才能较快速地使养殖大黄鱼的品质达到或接近野生大黄鱼的水平。

Large yellow croaker Pseudosciaena crocea Richardson is one of the commercially important marine finfish in China. It is popular in China as its high protein contents in muscle and better flesh quality such as better flavor and firmer flesh. Despite declines in natural stocks, large yellow croaker aquaculture industry has been well developed in south China with the success of artificial propagation and larval production since 1980s. However, the low flesh quality of farmed fish has created significant barriers for commercial aquaculture. An important reason is due to absence of selective breeding and nutritional requirement research. It is necessary to improve product quality of farmed fish for facilitating the development of large yellow croaker aquaculture industry. This study was conducted to analyze biochemical compositions of muscle of three crossbred stocks between F1 and F8 of Pseudosciaena crocea -WW： F1（♀）×F1 （♂）, WC： F1 （♀）×F8 （ ♂ ）, CC： F8 （♀）×F8 （♂）. The comparsion was made between the selected stocks and wild-caught P. crocea in nutrient contents. Ten two-year old fish of each stock cultured in floating net cages, located in Aquaculture TechnoL ogy Extension Station of0 Ningde, Fujian, and eight wild fish caught from Guanjingyang sea area of Ningde were sampled for analysis, respectively. Mean body weight of WW, WC and CC stocks were 383.14 g, 432.00 g and 337.10 g, respectively. Moisture was determined using a moisture balance, crude protein by Kjeldahl method, crude lipid by Soxhlet extraction method. Ash was determined in a muffle furnace at （550 ±15）℃. The amino acid composition of muscle was determined after acid hydrolysis and ninhydrin reactive substances of hydrolyzed materials were analyzed by an automatic amino acid analyzer （Hitachi 835 -50, Hitachi Instruments, Japan）. Fatty acid profile was determined after preparing methyl esters from crude lipid and fatty acid methyl esters were analyzed by gas liquid chromatography （Shimadzu GC2010, Tokyo, Japan）. The analysis results showed that WW stock had higher crude protein content （CP）, total essential amino acids content （TEA） and essential amino acids index （EAAI） （ CP： 67.32 %, TEA： 28.97%, EAAI： 64.7） than those of WC （CP： 66.16%, TEA： 28.33%, EAAI： 63.9） and CC （CP： 65.44 %, TEA： 27.35 %, EAAI： 62.1） stocks. Total unsaturated fatty acids contents were the highest in WC stock （60.7 % ）, followed by WW （57.8 % ） and CA2 （57.5 % ） stocks, while total saturated fatty acids contents showed an adverse order. These results suggest that the difference of nutritional components of muscle among the three stocks may attribute to parental inheritance, and the muscle quality could be modified by genetically improving together with meliorating rearing conditions and adjusting nutritional compositions of diet.