棉粕蛋白酶解物对异育银鲫(Carassius auratus gibelio)消化、生长和胰蛋白酶mRNA表达量的影响

EFFECT OF HYDROLYSATES OF COTTONSEED MEAL PROTEIN ON THE DIGESTIBILITY,GROWTH AND EXPRESSION LEVEL OF TRYPSINOGEN mRNA OF CARP CARASSIUS AURATUS GIBELIO

以棉粕蛋白为酶解底物,用枯草杆菌蛋白酶对其进行酶解,以酶解产物1.5%和3.0%两个梯度等量替代鱼饲料配方中棉粕,在室内流水养殖系统中喂养异育银鲫鱼种[体重为(30±2)g]65天。测定鱼的生长、营养物质表观消化率、消化蛋白酶活性及肝胰脏中胰蛋白酶mRNA表达水平等指标。结果表明,添加1.5%和3.0%棉粕酶解产物的鱼在饲养35天后的特定增长率(SGR)分别比对照组高32.5%和56.7%,且差异显著(P<0.05);在饲养65天后,两组特定增长率分别比对照组高8.0%和21.0%,且差异极显著(P<0.01),肝胰脏中胰蛋白酶mRNA表达水平也随棉粕酶解产物添加梯度提高而相应提高,表明鱼的生长与消化蛋白酶mRNA表达水平相关。同时棉粕蛋白酶解物对肠道蛋白酶的活性和营养物质表观消化率都有促进作用,而棉粕蛋白酶解物对鱼肌肉成分并没有改变,这也表明棉粕蛋白酶解物在促进鱼生长、内源酶活性同时并未降低鱼的品质。

To learn the effect of cottonseed meal protein hydrolysates （CMPH） in diets on the growth of carp Carassius auratus gibelio, intestine proteolytic activity and expression level of trypsinogen mRNA, and to study the relationship of intestine proteolytic activity and the production performance and biochemistry index of the carp, AS1. 398 neutrase was used to hydrolyze cottonseed meal protein under proper conditions, and CMPH was obtained. After that, in 65 days, the carps [ weight（30 ± 2）g] were fed with the diet containing 1.5% and 3.0% CMPH in a recirculation aquaculture system. At the end, indices were measured including growth index, apparent digestibility coefficient（ADC） of nutriment, proteinase activity and the expression level of trypsinogen mRNA. The result showed that the specific growth rate （SGR） of the fish in 35 days fed with 1.5% and 3.0% of CMPH were 32.5% and 56.7% higher than the control（fed with regular diet） respectively; 8. 0% and 21.0% in 65 days. The expression levels of trypsinogen mRNA were also enhanced. All the data suggest that the 3.0% CMPH group showed better performance in farming, and positively related to the growth, intestine proteolytic activity and the expression level, and the fish muscle quality remained unchanged. In conclusion, the hydrolysates could accelerate the growth and enhance obviously their physiological function and biological performance with high value of nutrition.