3种添加剂对花鲈消化酶活力、前肠组织结构及营养物质表观消化率的影响

Effects of 3 Additives on Digestive Enzyme Activities,Organizational Structure of Foregut and Nutrient Apparent Digestibility of Japanese Sea Bass(Lateolabrax japonicus)

本试验旨在研究饲料中添加复合核苷酸、植酸酶或复合芽孢杆菌对花鲈消化酶活力、前肠组织结构及营养物质表观消化率的影响。选取320尾初始体质量为(13.50±0.09)g的花鲈幼鱼,随机分成4组,每组4个重复,每个重复20尾。对照组(G0组)饲喂基础饲料,3个试验组分别饲喂在基础饲料中添加0.06%复合核苷酸(G1组)、0.04%植酸酶(G2组)、0.10%复合芽孢杆菌(G3组)的试验饲料。饲养周期为56 d。结果显示:各试验组前肠、肝脏和胃的蛋白酶活力与G0相比无显著差异(P>0.05)。G2组的肝脏淀粉酶活力显著高于G0组(P<0.05);G1组的前肠脂肪酶活力显著低于G0组(P<0.05);各组间前肠和胃淀粉酶、肝脏和胃脂肪酶活力差异不显著(P>0.05)。饲料中添加3种添加剂均能显著增加前肠肌层厚度和绒毛高度(P<0.05),增加固有层和上皮细胞间的紧密度,其中以植酸酶效果最为显著。与G0组相比,G1组的干物质表观消化率显著升高(P<0.05);粗蛋白质、粗脂肪和总能表观消化率各组间差异不显著(P>0.05)。与G0组相比,G1和G3组粗灰分表观消化率显著升高(P<0.05),G2组粗灰分表观消化率则显著降低(P<0.05)。由此可见,饲料中添加植酸酶能显著提高花鲈肝脏淀粉酶活力和干物质表观消化率,显著降低粗灰分表观消化率;饲料中添加复合核苷酸能显著降低花鲈前肠脂肪酶活力,显著提高粗灰分表观表消化率;此外,饲料中添加复合核苷酸、植酸酶或复合芽孢杆菌均能改善花鲈前肠组织结构。

This experiment was conducted to evaluate the effects of diet supplemented with nucleotides,phytase or complex bacillus on digestive enzyme activities,the organizational structure of foregut and nutrient apparent digestibility of Japanese sea bass(Lateolabrax japonicus).A total of 320 juvenile Lateolabrax japonicus with an initial body weight of(13.50±0.09)g were randomly divided into 4 groups with 4 replicates per group and 20 fish per replicate.Fish in control group(group G0)were fed a basal diet,and those in 3 trial groups were fed the basal diet supplemented with 0.06%nucleotides(group G1),0.04%phytase(group G2)and 0.10%complex bacillus(group G3),respectively.The experiment lasted for 56 d.The results showed that there was no significant difference in the protease activity of foregut,liver and stomach in the 3 trial groups compared with group G0(P>0.05).The activity of liver amylase in group G2 was significantly higher than that in group G0(P<0.05).The activity of foregut lipase in group G1 was significantly lower than that in G0 group(P<0.05).But there were no significant differences in the activities of liver,stomach lipase and foregut and stomach amylase among all groups(P>0.05).Diet supplemented with 3 additives all could improve the thickness of muscular layer and villus height of foregut,and also could increase the tight between the inherent layer and epithelial cells,and the phytase had the most dramatic effect.Compared with group G0,the apparent digestibility of dry matter in group G1 was significantly increased(P<0.05),but there was no significant difference in the apparent digestibility of crude protein,crude fat and gross energy among all groups(P>0.05).The apparent digestibility of ash in groups G1 and G3 was significantly increased compared with group G0(P<0.05),but that in group G2 was significantly decreased(P<0.05).In conclusion,dietary phytase can significantly increase the amylase activity of liver and the apparent digestibility of dry matter of Lateolabrax japonicus;dietary nucleotides can significantly decrease the lipase activity of foregut and significantly increase the apparent digestibility of ash of Lateolabrax japonicus;in addition,dietary nucleotides,phytase or bacillus all can improve the organizational structure of foregut of Lateolabrax japonicus.