低鱼粉饲料中黑水虻幼虫粉替代鱼粉对合方鲫生长性能、消化能力、血浆生化指标及相关基因表达的影响

REPLACING FISH MEAL WITH HERMETIA ILLUCENS LARVAE MEAL ON GROWTH PERFORMANCE,DIGESTIVE CAPACITY,PLASMA BIOCHEMICAL INDEXES AND RELATED GENES EXPRESSION IN HEFANG CRUCIAN CARP

实验以合方鲫2号幼鱼(31.50±0.50)g为实验对象,研究黑水虻幼虫粉(HM)替代饲料鱼粉(0、20%、40%、60%和80%)对合方鲫生长性能、饲料利用、消化能力、血浆生化指标及相关基因表达的影响。实验设计5组等氮(30%)等能(18.50 MJ/kg)等脂(6%)饲料,每组3次重复,每个重复25尾鱼,养殖时间74d。结果表明:增重率和特定生长率随饲料HM含量的升高呈现先升高后降低趋势,且在替代水平为20%时最大;饲料系数呈先降低后升高的趋势,20%替代组显著小于60%和80%替代组(P<0.05)。肥满度和脏体比均呈现先升高后降低趋势,且均在40%替代组最大;80%替代组肝体比显著高于0、20%和60%替代组(P<0.05),但与40%替代组无显著差异。全鱼水分和灰分无显著变化;20%和60%替代组粗蛋白显著低于0组(P<0.05);粗脂肪呈先升高后降低的变化趋势,在20%替代组达到最大值。血浆葡萄糖、总胆固醇含量及谷丙转氨酶、谷草转氨酶活性无显著差异;血氨含量呈上升趋势,80%替代组显著高于0组;20%替代组血浆总氨基酸含量显著高于其他各处理组(P<0.05);60%和80%替代组血浆丙二醛含量显著低于20%替代组(P<0.05)。20%替代组肠道中lat2、pept1和cdx2基因的表达量均高于其他各处理组,asct2基因表达水平则在替代水平为40%时最大;肝脏中tor和igf1基因表达量均在40%替代组最大,gh和ghr基因表达水平则均在替代水平为60%时最高。黑水虻幼虫粉替代饲料中鱼粉的0—40%不影响合方鲫的生长,且在20%替代水平时可获得最大生长速率。

To investigate the effects of dietary replacement fishmeal protein with Hermetia illucens larvae meal(HM)on growth performance,digestive capacity,plasma biochemical indexes and related genes expression in Hefang crucian carp(Carassis auratus),five isonitrogenous(30%),isolipidic(6%)and isoenergetic(18.50 MJ/kg)diets were formulated to contain graded levels of fishmeal protein replacement by HM(0,20%,40%,60%and 80%respectively)for a 74-day feeding trial.Each treatment was randomly assigned to triplicate groups of 25 fish[initial body weight of(31.50±0.50)g]per aquarium.Fish were fed twice daily to apparent satiation.Results showed that the weight gain rate(WGR)and specific growth rate(SGR)first increased and then decreased with the increased proportion of HM in diets,with a maximum in the 20%substitution group.Feed conversion ratio(FCR)showed an initial decrease followed by an increase,and the 20%substitution group was significantly less than 60%and 80%substitution groups(P<0.05).With the increased proportion of HM in diets,condition factor(CF)and viscerosomatic index(VSI)first increased and then decreased,with a maximum in the 40%substitution group.The hepatopancreas somatic index(HSI)of 80%substitution group was significantly higher than those in 0,20%and 60%substitution groups(P<0.05),but there was no significant difference between 40%and 80%substitution group.The moisture and ash of fish body expressed no significant difference.However,crude protein of body in 20%and 60%substitution group was significantly lower than that in 0 group(P<0.05).Crude lipid of body showed an initial increase followed by a decrease,and the highest value was seen in 20%substitution group.There was no significant difference in plasma glucose concentration,total cholesterol concentration,alanine aminotransferase and aspartate aminotransferase activity,but blood ammonia content showed an upward trend,the blood ammonia of 80%substitution group was significantly higher than that of 0 substitution group.Total plasma amino acid in the 20%substitution group was significantly higher than those in the other treatments(P<0.05).Plasma malondialdehyde was significantly lower in 60%and 80%substitution groups than that in 20%substitution group(P<0.05).The expression of lat2,pept1 and cdx2 genes in the intestine reached to the highest level in 20%substitution group,while asct2 gene showed the highest expression in 40%substitution group.The expression of tor and igf1 genes in liver was the highest in 40%substitution group,while the highest expression of gh and ghr genes were seen in 60%substitution group.These results suggested that 0—40%of fish meal in the diet of HCC could be substituted by HM,and 20%was the optimal optimum proportion.