氧化油脂对斑点叉尾鮰生长、体色和抗氧化能力的影响

为考察正常及氧化鱼油、豆油、混合油脂(鱼油﹕豆油=1﹕1)对斑点叉尾鮰(Ictalurus punctatus)生长性能、体色和肝脏抗氧化能力的影响, 设计6组等氮等脂饲料, 分别添加6%鱼油、6%豆油、3%鱼油+3%豆油、6%氧化鱼油、6%氧化豆油、3%氧化鱼油+3%氧化豆油, 饲喂6组初始体重(150.5±4.2 g)的斑点叉尾鮰8周, 每组3个重复, 每个重复14尾鱼。结果表明, 摄食6%鱼油、6%豆油、3%鱼油+3%豆油饲料的斑点叉尾鮰在增重率、饲料系数、肌肉组成、体色和肝脏抗氧化指标上均无显著差异(P>0.05); 摄食3组氧化油脂饲料后, 鱼体增重率和肌肉粗脂肪含量降低(P<0.05), 饲料系数和背部、尾部皮肤b*(黄度值)增加(P<0.05), 肝脏丙二醛(MDA)和血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、总胆红素(TBIL)和直接胆红素升高(DBIL)(P<0.05), 肝脏超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、还原型谷胱甘肽降低(GSH)(P<0.05), 而肌肉色度值(L*、a* 、b*)和肌肉水分、粗蛋白质、灰分含量无显著差异(P>0.05)。以上结果表明, 6%氧化油脂(鱼油、豆油或混合油脂)导致斑点叉尾鮰生长性能下降、皮肤黄度增加、肝脏抗氧化能力受损; 豆油可替代斑点叉尾鮰饲料中鱼油的使用, 而不会对生长产生负面影响。

EFFECT OF OXIDIZED OILS ON GROWTH,BODY COLOR AND ANTIOXIDANT CAPACITY OF CHANNEL CATFISH, ICTALURUS PUNCTATUS

Oils are widely used in aquatic feed to supply essential fatty acids and energy for the fish. However, the abundance of unsaturated fatty acids makes oils susceptible to be oxidized, resulting in harmful effect on the health of fish. To investigate the effect of dietary oxidized oils on the growth performance, body color and antioxidant capacity in liver of channel catfish, Ictalurus punctatus, six isonitrogenous and isolipidic diets were prepared to feed channel catfish (150.5±4.2) g. The six diets were designed with 6% supplementation level of fish oil (FO-6), soybean oil (SO-6), mixed oil (3% fish oil + 3% soybean oil, MO-6), oxidized fish oil (OFO-6), oxidized soybean oil (OSO-6), oxidized mixed oil (3% oxidized fish oil + 3% oxidized soybean oil, OMO-6), respectively. After 8 weeks feeding, the fish fed FO-6, SO-6 or MO-6 diet showed no differences in weight gain (WG), feed conversion ratio (FCR), muscle composition, body color and antioxidant indicators in liver (P>0.05), which indicated that soybean oil could completely substitute the inclusion of fish oil in the diet of channel catfish. The WG and muscle lipid level of the three oxidized oil groups were significantly lower, andFCR, skin yellowness, liver malondialdehyde content, and total bilirubin, direct bilirubin, alanine aminotransferase, aspartate aminotransferase in serum were significantly higher (P<0.05) than that of the normal oil groups. The activities of catalase and superoxide dismutase, and the glutathione contents in liver were reduced by dietary oxidized oils (P<0.05), but the dorsal muscle color and moisture, crude protein, ash content in flesh were not affected (P>0.05). The above results showed that 6% oxidized oils (fish oil, soybean oil, or mixed oil) reduced the growth performance, increased the yellowness of skin and damaged the antioxidant capacity of liver of channel catfish. Soybean oil could completely replace the fish oil inclusion in the diet of channel catfish.