大豆分离蛋白替代鱼粉对哲罗鱼消化生理的影响

Effects of fish meal replacement by soybean protein isolate on digestive physiology of taimen Hucho taimen

为研究大豆分离蛋白替代鱼粉后对哲罗鱼Hucho taimen消化系统组织结构和消化酶活性的影响,在水温为9. 8～16. 2℃时,将初始体质量为(6. 90±0. 04) g的哲罗鱼饲养于室内220 L玻璃钢水族箱中,分别投喂大豆分离蛋白替代0、25. 0%、37. 5%、50. 0%、62. 5%、75. 0%、87. 5%和100. 0%鱼粉的饲料,每个处理设3个重复,每个重复放100尾鱼,以含有40. 0%鱼粉的饲料为对照,试验时间为56 d。结果表明:随着鱼粉替代比例的增加,哲罗鱼胃、前肠、幽门盲囊、中肠和胰腺的蛋白酶、脂肪酶和淀粉酶活性均呈显著下降趋势(P<0. 05);肠道绒毛和纹状缘高度亦呈显著下降趋势(P<0. 05);高比例替代鱼粉水平(>75%)时,哲罗鱼肠道组织结构完整性被破坏,纹状缘融合、部分脱落,肝脏空泡化现象严重,形态轮廓逐渐模糊,肝细胞核偏移,且溶解或缺失。研究表明,大豆分离蛋白高比例替代鱼粉水平(>75%)显著降低消化系统消化酶活性,损伤肝脏和肠道组织。

Taimen Hucho taimen with initial body weight of(6.90±0.04)g were reared in a 220 L indoor flowing glass fiber reinforced plastic tank and fed diets in which fish meal was replaced by 0,25.0%,37.5%,50.0%,62.5%,75.0%,87.5%and 100.0%of soy protein isolate(SPI),diet containing 40.0%fish meal as control,with triplicates of each 100 fish at water temperature of 9.8-16.2℃for 56 d to evaluate the effects of replacing fish meal with SPI on the activities of digestive enzymes and histological structure of digestive tract of taimen.It was found that protease,lipase and amylase activities in stomach,foregut,midgut,pyloric caeca and pancreas were significantly decreased with increasing SPI content(P<0.05).Heights of intestinal villi and microvilli were also shown to be significant decrease(P<0.05),and damaged intestinal structural integrity,fused microvilli,even abscission,and more hepatic vacuoles were observed in the taimen fed high dietary levels of SPI(87.5%and 100.0%)under a microscope,even with blurred boundaries,and shifted and dissolved or vanished nuclei in hepatic cells.It is concluded that fish meal replacement by high level of SPI leads to decline the digestive enzyme activity and to cause loss of function of liver and intestine.