大菱鲆幼鱼对玉米蛋白粉中营养物质的表观消化率及添加胆汁酸和酶制剂对其产生的影响

本试验旨在研究大菱鲆幼鱼对玉米蛋白粉中干物质、粗蛋白质、氨基酸和总能的表观消化率,以及在玉米蛋白粉中分别添加胆汁酸(纯度≥30%)和酶制剂中性蛋白酶(1×105 U/g)和木瓜蛋白酶(4×105 U/g)组成的复合酶,二者活性比为2∶1]对其营养物质表观消化率的影响。首先配制基础饲料,试验饲料由70%的基础饲料和30%的待测蛋白质源未进行任何处理的玉米蛋白粉(CGM)、添加胆汁酸的玉米蛋白粉(CGMB)和添加酶制剂的玉米蛋白粉(CGME)]组成。所有饲料均添加0.1%的三氧化二钇(Y2O3)为外源指示剂。将初始体重为(13.00±0.01)g大菱鲆幼鱼随机分为4组,每组3个重复,每个重复40尾鱼,分别投喂相应饲料2周后采用后肠挤压法收集粪便。养殖周期为10周。结果表明:3种不同处理形式的玉米蛋白粉中干物质、粗蛋白质、总氨基酸、总能的表观消化率分别为25.99%~43.34%、48.62%~60.72%、48.41%~67.67%、35.07%~52.34%,且总氨基酸与粗蛋白质表观消化率的变化趋势一致。其中,大菱鲆幼鱼对CGMB中各营养物质的表观消化率均最高,显著高于CGM和CGME(P0.05),且CGMB中干物质、粗蛋白质、总氨基酸、总能的表观消化率较CGM分别提高了17.35%、12.10%、19.26%、17.27%;大菱鲆幼鱼对CGME中各营养物质的表观消化率也得到改善,其干物质、粗蛋白质、氨基酸、总能的表观消化率较CGM分别提高了9.53%、4.37%、4.29%、12.25%,效果显著(P0.05)。由结果可知,添加胆汁酸和酶制剂均能够提高大菱鲆幼鱼对玉米蛋白粉中营养物质的表观消化率。

Nutrient Apparent Digestibility Coefficients of Corn Gluten Meal for Juvenile Turbot (Scophthalmus maximus L.) and Effects of Adding Bile Acid and Enzyme Preparation on Them

This experiment was conducted to determine the apparent digestibility coefficients (ADCs) of dry matter (DM),crude protein (CP),amino acid (AA) and gross energy (GE) of corn gluten meal,and the effects of adding bile acid (purity≥30%) and enzyme preparation compound enzyme which was composed of neutral protease (1×105 U/g) and papain (4×105 U/g),and the activity ratio of them was 2∶1] on ADCs of nutrients in corn gluten meal.A basal diet was prepared firstly,and then the test diets were prepared which contained 70% basal diet and 30% test feed ingredients untreated corn gluten meal (CGM),corn gluten meal supplemented with bile acid (CGMB),and corn gluten meal supplemented with enzyme preparation (CGME)].All diets were added 0.1% yttrium trioxide as an exogenous indicator.Juvenile turbot with the average body weight of (13.00±0.01) g were randomly divided into 4 groups with 3 replicates in each group and 40 fish in each replicate.The fish in different group were fed with the corresponding diet,and fecal samples were collected with the method of squeezing the hindgut after 2 weeks.The feeding period was 10 weeks.The results showed that the ADCs of DM,CP,total AA and GE of three protein sources were 25.99% to 43.34%,48.62% to 60.72%,48.41% to 67.67%,and 35.07% to 52.34%,respectively.The ADC of total AA of each protein source presented the similar tendency with the ADC of CP.CGMB showed the highest ADCs of all nutrients for juvenile turbot,which were significantly higher than those of CGM and CGME (P<0.05),and the ADCs of DM,CP,total AA and GE of CGMB were increased by 17.35%,12.10%,19.26% and 17.27%,respectively,compared with CGM;the ADCs of all nutrients of CGME for juvenile turbot were also improved,the ADCs of DM,CP,total AA and GE of CGMB were increased by 9.53%,4.37%,4.29% and 12.25%,respectively,compared with CGM,and the effects were significant (P<0.05).The results indicate that adding bile acid and enzyme preparation all contribute to the improvement of ADCs of nutrients of corn gluten meal for juvenile turbot.