盐度对草鱼生长和肌肉品质的影响

Effect of different salinities on growth and flesh quality of Ctenopharyngodon idellus

为考察盐度对草鱼生长和肌肉品质的影响,设置盐度为0(对照组),5.0、7.5、10.0的4个水平,饲养平均体重为(725±42)g的草鱼30d,测定草鱼生长性能、肌肉营养成分和肌肉物理性能指标。结果表明,在0、5.0、7.5盐度中草鱼生长良好,成活率均为100%,增重率为27.6%、28.3%、26.4%,但在盐度为10.0的水体中,草鱼成活率和增重率均极显著降低(P<0.01),仅为60%、4.5%,而饲料系数显著上升(P<0.01);在肌肉基本营养成分方面,盐度为0,5.0,7.5各组草鱼肌肉水分、粗蛋白、灰分含量无显著差异,但盐度为10的草鱼组肌肉水分含量显著增加,粗蛋白含量降低。经过不同盐度水体暂养后,草鱼肌肉中脂肪含量显著减少(P<0.01),胶原蛋白含量增加,肌纤维耐折力提高,肌纤维直径减小,而盐度对肌肉失水率的影响则呈现不同的特点,其中5.0、10.0盐度使肌肉失水率显著上升(P<0.01),而7.5盐度则使肌肉失水率显著下降(P<0.01)。上述结果表明,半咸水暂养草鱼可改善其肌肉品质,适宜的盐度值为7.5。

To investigate the effect of salinity on growth and flesh quality of grass carp, different salinity （0, 5.0, 7.5, 10.0） was made up to raise grass carp with body weight of （725 ±42） g for 30 days, then growth performance, muscle nutrients composition and physical parameter were determined. Results showed that the growth rate was 27.6% ,28.3% ,26.4% ,6.5%, survival rate was 100%, 100%, 100% ,60% for grass carp of the four groups, and there was no significant difference in growth performance among 0, 5.0, 7.5 salinity groups, but growth rate and survival rate were significantly decreased and FCR increased for grass carp fed in 10.0 salinity water （ P 〈 0.01 ）. About muscle chemical composition, there was no difference in muscle moisture, crude protein, crude ash among 0.0, 5.0, 7.5 salinity groups, but muscle crude protein content was decreased and moisture increased at 10.0 salinity （ P 〈 0.01 ）. Crude fat content, muscle fibre diameter were decreased, and myfibrillae lengths, collagen content increased by feeding in brackish water （5.0, 7.5, 10.0 salinity）. Muscle water-loss rate was increased at 5.0, 10.0 salinity, and decreased at 7.5 salinity. Results above showed that the meat quality of the grass carp could be improved by feeding in brackish water with the proper salinity of 7.5 salinity.