论文部分内容阅读
研究了饲料中不同水平n-3 HUFA(0.79%,0.83%,0.85%,0.88%,0.92%,0.94%;DHA/EPA=2.8/1)对黑鲷幼鱼生长及脂肪代谢的影响。结果显示:(1)黑鲷幼鱼肝体指数(HSI)及腹脂率(IPF ratio)随饲料中n-3 HUFA含量的增加而减小,且于0.92%和0.94%组时显著低于其他各组;脂肪细胞直径呈减小趋势,其中0.94%组显著小于0.85%组;肌肉脂肪含量受n-3 HUFA的影响显著,于0.88%组时达到最低。各组全鱼水份和脂肪含量差异不显著(P>0.05)。肝脏、肌肉及腹腔脂肪组织饱和脂肪酸(∑SFA)和C16∶0含量均随饲料n-3HUFA水平增加呈下降趋势,而∑n-3 HUFA呈显著上升趋势。各组织中DHA/EPA不受饲料脂肪酸组成的影响。以增重率为参考指标,二次回归分析结果表明,黑鲷幼鱼[(8.08±0.09)g]获得最佳增重时对饲料中n-3 HUFA的需要量为0.87%DM;(2)黑鲷幼鱼肝脏脂肪酸合成酶(FAS)活性及基因表达水平均在n-3 HUFA>0.92%时有显著下降(P<0.05);腹腔脂肪激素敏感脂肪酶(HSL)活性及基因表达水平均随饲料中n-3 HUFA的添加呈升高趋势(P<0.05),且高含量n-3 HUFA(0.94%)可使HSL活性增加近一倍。结果表明,饲料中n-3HUFA通过同步调控脂肪合成与分解两个过程影响黑鲷幼鱼脂肪代谢。
The effects of different levels of n-3 HUFA (0.79%, 0.83%, 0.85%, 0.88%, 0.92%, 0.94%, and DHA / EPA = 2.8 / 1) on juvenile black fish growth and fat metabolism were studied. The results showed that: (1) HSI and IPF of juvenile black sea bream decreased with the increase of n-3 HUFA content, and were significantly lower than that of 0.92% and 0.94% In other groups, the diameter of adipocytes showed a decreasing trend, of which 0.94% was significantly less than 0.85%, and the muscle fat content was significantly affected by n-3 HUFA, reaching the lowest at 0.88%. There was no significant difference in moisture and fat content of whole fish in each group (P> 0.05). The saturated fatty acids (ΣSFA) and C16:0 contents of liver, muscle and abdominal fat tissue all decreased with the increase of n-3HUFA level, while Σn-3 HUFA showed a significant increase. DHA / EPA in each tissue was unaffected by feed fatty acid composition. The weight gain rate was used as a reference index. The results of quadratic regression analysis showed that the requirement for n-3 HUFA in feeds was (0.81%) DM [(8.08 ± 0.09) g] ), Liver fatty acid synthetase (FAS) activity and gene expression of juvenile black sea bream were significantly decreased (P <0.05) when n-3 HUFA> 0.92%, while the activity and gene expression level of abdominal adipose hormone sensitive lipase (P <0.05). The high level of n-3 HUFA (0.94%) could almost double the HSL activity. The results showed that n-3HUFA in feed affects the fat metabolism of juvenile black sea bream by synchronously regulating fat synthesis and decomposition.