菜籽粕替代鱼粉对青鱼生长、抗氧化能力和肠道健康的影响

Effects of Rapeseed Meal Replacing Fish Meal on Growth,Antioxidant Capacity and Intestinal Health of Black Carp(Mylopharyngodon piceus)

本试验旨在研究菜籽粕替代鱼粉对青鱼(Mylopharyngodon piceus)生长、抗氧化能力和肠道健康的影响。用菜籽粕分别替代基础饲料中0(对照组)、10%(10%组)、20%(20%组)、30%(30%组)、40%(40%组)和50%(50%组)的鱼粉,配制6种等氮等脂的试验饲料,饲喂初始体重为(6.73±0.70)g的青鱼8周。每种试验饲料投喂4个养殖桶,每桶放养35尾鱼。结果显示:1)对照组、10%组和20%组增重率和特定生长率无显著差异(P>0.05),30%、40%和50%组的增重率和特定生长率显著低于对照组和10%组(P<0.05)。随着菜籽粕替代鱼粉比例的增加,肥满度、肝体比和肠体比呈现下降的趋势,饲料系数呈现先下降后上升的趋势,50%组的饲料系数显著高于对照组、10%组和20%组(P<0.05)。2)各组全鱼的水分和粗灰分含量无显著差异(P>0.05);随着菜籽粕替代鱼粉比例的增加,全鱼的粗蛋白质和粗脂肪含量呈现下降的趋势,40%和50%组全鱼的粗蛋白质和粗脂肪含量显著低于对照组(P<0.05)。各组肌肉的水分、粗脂肪和粗灰分含量无显著差异(P>0.05);30%组、40%组和50%组肌肉的粗蛋白质含量显著低于对照组(P<0.05)。3)各组干物质和粗脂肪表观消化率无显著差异(P>0.05),20%组、30%组、40%组和50%组粗蛋白质表观消化率显著低于对照组(P<0.05)。当饲料中菜籽粕替代鱼粉比例超过10%时,肠道胰蛋白酶、脂肪酶和淀粉酶活性均显著下降(P<0.05)。4)血清总抗氧化能力和超氧化物歧化酶活性随着菜籽粕替代鱼粉比例的增加呈下降趋势,但各组间无显著差异(P>0.05)。当菜籽粕替代鱼粉比例高于20%时,血清过氧化氢酶活性显著降低(P<0.05),血清丙二醛含量显著升高(P<0.05)。5)当菜籽粕替代鱼粉比例超过10%时,肠绒毛长度、宽度和肌层厚度显著下降(P<0.05)。在门水平上,青鱼肠道菌群中的优势菌门为变形菌门、拟杆菌门和放线菌门;在属水平上,青鱼肠道菌群中的优势菌属为金黄杆菌属、无色杆菌属和气单胞菌属。菜籽粕替代20%和50%的鱼粉提高了青鱼肠道菌群中变形菌门和气单胞菌属的相对丰度。综上所述,青鱼饲料中菜籽粕替代鱼粉的比例以不超过20%为宜,此时不会对青鱼的生长和抗氧化能力产生明显的负面影响。

This experiment aimed to investigate the effects of rapeseed meal replacing fish meal on the growth,antioxidant capacity and intestinal health of black carp(Mylopharyngodon piceus).Six isonitrogen and isolipid diets were designed and prepared by replacing 0(control group),10%(10%group),20%(20%group),30%(30%group),40%(40%group)and 50%(50%group)of fish meal with rapeseed meal based on a basal diet,respectively.The black carp with an initial body weight of(6.73±0.70)g were fed the experimental diets for 8 weeks.Each experimental diet was fed to 4 breeding buckets with 35 fish per bucket.The results showed as follows:1)there were no significant differences in weight gain rate(WGR)and specific growth rate(SGR)among the control group,10%group and 20%group(P>0.05),while the WGR and SGR in the 30%group,40%group and 50%group were significantly lower than those in the control group and 10%group(P<0.05).With the rapeseed meal replacement level increasing,the condition factor(CF),hepatosmatic index(HSI)and intestinosomatic index(ISI)were decreased,and the feed conversion ratio(FCR)firstly decreased and then increased.The FCR in the 50%group was significantly higher than that in the control group and 10%group(P<0.05).2)There were no significant differences in the moisture and ash content of whole fish among groups(P>0.05);the crude protein and crude lipid contents of 30%group,40%group and 50%group were decreased with the rapeseed meal replacement level increasing,and those in the 40%group and 50%group were significantly lower than those in the control group(P<0.05).There were no significant differences in moisture,ash and crude lipid of muscle among groups(P>0.05),while the crude protein content of muscle in the 30%group,40%group and 50%group was significantly decreased compared with the control group(P<0.05).3)There were no significant differences in the apparent digestibility coefficients of dry matter and crude lipid among groups(P>0.05).The apparent digestibility coefficient of crude protein in the 30%group,40%group and 50%group was significantly lower than that in the control group(P<0.05).When the fish meal replaced by rapeseed meal exceeded 10%,the activities of intestinal trypsin,lipase and amylase in intestine were significantly decreased compared with control group(P<0.05).4)The total antioxidant capacity(T-AOC)and superoxide dismutase(SOD)activity in serum showed a decreasing trend among the experimental groups,but there were no significant differences among groups(P>0.05).When the fish meal replaced by rapeseed meal exceeded 20%,serum catalase(CAT)activity was significantly decreased(P<0.05),and serum malondialdehyde(MDA)content was significantly increased(P<0.05).5)The intestinal villi length,villi width and muscle thickness decreased significantly when the fish meal replaced by rapeseed meal exceeded 10%(P<0.05).At phylum level,the dominant microbial phyla in intestinal flora of black carp were Proteobacteria,Bacteroidetes and Actinobacteria.At genus level,the dominant microbial genera in intestinal flora of black carp were Chrysobacillus,Achromobacillus and Aeromonas.The relative abundances of Proteobacteria and Aeromonas were when 20%and 50%fish meal replaced by rapeseed meal.In summary,an appropriate proportion of rapeseed meal instead of fish meal in the diet of black carp should not exceed 20%,which will not have noticeable adverse effects on the growth and antioxidant capacity of black carp.