露水草粉碎粒度和添加水平对日本沼虾生长性能、肝胰腺消化酶活性及非特异性免疫指标的影响

摘要

This experiment were conducted to evaluate the effects of Cyanotis arachnoidea C. B. Clarke(C. arachnoidea)which was rich in ecdysone on the growth performance,hepatopancreas digestive enzyme activi?ties and nonspecific immune indices of Macrobrachium nipponensis. In trial 1, C. arachnoidea with different grinding granularities(grinding granularity was 10,30,50 and 180 μm,respectively)were added into a basal diet(without C. arachnoidea), and to make the ecdysone content in experimental diets was all 10 mg/kg; in trial 2, C. arachnoidea with the same grinding granularity(grinding granularity was 180 μm)at different ecdysone contents were added into the basal diet, and to make the ecdysone content in experimental diets was 3.30,6.60,13.20,26.40 mg/kg, respectively. There were 8 experimental diets were prepared, which were used to fed Macrobrachium nipponensis with the average body weight of(0.08±0.01)g for 60 days. One con?trol group was set in trials 1 and 2,respectively,and Macrobrachium nipponensis in control group were fed the basal diet. Each diet had 3 replicates with 70 shrimps in each replicate. After the feeding experiment, the prawns were challenged with Aeromonas hydrophila. The results showed as follows: in the trial 1, compared with the control group,the weight gain rate(WGR),specific growth rate(SGR)in the groups with different grinding granularities of C. arachnoidea were significantly increased(P<0.05), and the feed conversion ratio (FCR)was significantly decreased(P<0.05);there were no significant differences in the survival rate(SR), hepatopancreas index(HSI), the activities of pepsin, tryptase and amylase in hepatopancreas, total hemocyte count(THC), haemolymph phagocytic(HPA), the activities of superoxide dismutase(SOD)and alkaline phosphatase(AKP)in plasma among all groups(P>0.05);the cumulative mortality was not significantly dif?ferent among all groups after treatment with Aeromonas hydrophila(P>0.05). In the trial 2, compared with the control group, the WGR and SGR in the 6.60 and 13.20 mg/kg ecdysone groups were significantly in?creased(P<0.05)and their FCR were significantly decreased(P<0.05); the WGR, SGR, SR and HPA in the 26.40 mg/kg ecdysone group were significantly lower than those in the control group(P<0.05), and the WGR and SGR in the 26.40 mg/kg ecdysone group were also significantly lower than those in the other C. arachnoidea additon groups(P<0.05), and there were no significant differences in WGR and SGR among 3.30,6.60 and 13.20 mg/kg ecdysone groups(P>0.05); there were no significant differences in the HSI, the activities of pepsin,tryptase and amylase in hepatopancreas,THC,the activities of SOD and AKP in plas?ma among all groups(P>0.05); the cumulative mortality in 26.40 mg/kg ecdysone group was significantly higher than that of other groups after treatment with Aeromonas hydrophila(P<0.05). These results demon?strate that, the addition of the appropriate amount of C. arachnoidea to the diets making diet ecdysone contents are 6.60 to 13.20 mg/kg can significantly promote the growth of Macrobrachium nipponensis,and the absorp?tion of ecdysone by Macrobrachium nipponensis has no significant correlation with the grinding granularity of C. arachnoidea. The main medicinal ingredient of C. arachnoidea, ecdysone has no immune enhancement effect on Macrobrachium nipponensis, and excess C. arachnoidea ecdysone(diet ecdysone content is 26.40 mg/kg)can lead SR and anti?bacterial ability.%本试验旨在研究富含蜕皮激素的露水草(Cyanotis arachnoidea C.B.Clarke)对日本沼虾生长性能、肝胰腺消化酶活性及非特异性免疫指标的影响.试验1:分别将粉碎粒度为10、30、50和180 μm的露水草添加到基础饲料(不含露水草)中,并使饲料中蜕皮激素含量均为10 mg/kg;试验2:将粉碎粒度相同(粉碎粒度为180 μm)但蜕皮激素含量不同的露水草添加到基础饲料中,使饲料中蜕皮激素含量分别为3.30、6.60、13.20和26.40 mg/kg.将配制的8种试验饲料分别饲喂初始体重为(0.08 ± 0.01)g的日本沼虾,同时试验1和试验2中各设1个饲喂基础饲料的对照组.每种饲料设3个重复,每个重复70尾,试验期60 d.饲养试验结束后对各组日本沼虾进行嗜水气单胞菌感染试验.结果显示:在试验1中,与对照组相比,添加不同粉碎粒度露水草组日本沼虾的特定生长率(SGR)和增重率(WGR)均显著升高(P<0.05),饲料系数(FCR)显著降低(P<0.05);成活率(SR),肝胰腺指数(HSI),肝胰腺胃蛋白酶、类胰蛋白酶和淀粉酶活性,血细胞总数(THC),血淋巴吞噬活性(HPA)以及血浆超氧化物歧化酶(SOD)和碱性磷酸酶(AKP)活性各组之间无显著差异(P>0.05);各组日本沼虾经嗜水气单胞菌处理后的累积死亡率无显著差异(P>0.05).在试验2中,与对照组相比,6.60 mg/kg 蜕皮激素组和13.20 mg/kg蜕皮激素组的 WGR 和 SGR 显著升高(P<0.05),FCR 显著降低(P<0.05);26.40 mg/kg蜕皮激素组的WGR、SGR、SR和HPA显著低于对照组(P<0.05),其WGR和SGR也显著低于其他添加露水草组(P<0.05);3.30 mg/kg 蜕皮激素组、6.60 mg/kg 蜕皮激素组、13.20 mg/kg蜕皮激素组之间WGR和SGR差异不显著(P>0.05);各组日本沼虾的HSI,肝胰腺胃蛋白酶、类胰蛋白酶和淀粉酶活性,THC 以及血浆 SOD、AKP 活性的差异均不显著(P>0.05);26.4 mg/kg蜕皮激素组经嗜水气单胞菌处理后的累积死亡率与其他组相比显著升高(P<0.05).由此可见,饲料中添加露水草使蜕皮激素含量达到6.60~13.20 mg/kg时对日本沼虾具有显著的促生长作用,日本沼虾对蜕皮激素的吸收和露水草的粉碎粒度无显著相关性.露水草主要药用成分蜕皮激素对日本沼虾无免疫增强作用,且露水草蜕皮激素过量(饲料中蜕皮激素含量为26.4 mg/kg)还将导致日本沼虾SR和抗菌能力降低.