虫草培养基残余体在中华绒螯蟹饲料中的适宜添加量

Optimal supplementation level of residual Cordyceps militaris culture medium for feeding Chinese mitten crab(Eriocheir sinensis)

在基础饲料中分别添加0.25%、0.5%、1.0%、2.0%、4.0%、8.0%、16.0%的虫草培养基残余体(简称虫草基),饲喂规格为(4.0±1.0)g的中华绒螯蟹(Eriocheir sinensis)75 d,通过测定其生长及非特异性免疫指标,以确定虫草基的适宜添加量。结果显示:与基础饲料组比较,0.5%和1.0%添加组平均增重率(WGR)、肥满度(CF)、成活率(SR)显著提高(P<0.05),饲料系数(FC)显著降低(P<0.05);除肥满度(CF)外,4.0%、8.0%、16.0%添加组的生长指标有所下降。低剂量虫草基添加组能提高中华绒螯蟹血淋巴及肝胰腺超氧化物歧化酶(SOD)、溶菌酶(LSZ)、酸性磷酸酶(ACP)、碱性磷酸酶(ALP)活性,其中,0.5%与1.0%添加组的SOD、LSZ、ACP和ALP水平均达显著水平(P<0.05);但当虫草基添加量超过2.0%时,中华绒螯蟹的非特异性免疫力逐渐下降。嗜水气单胞菌(Aeromonas hydrophila AHJ-1)攻毒试验证实,试验组的免疫保护率明显提高,0.5%添加组免疫保护率达100%。综上所述,虫草基作为中华绒螯蟹饲料添加剂的适宜添加量为0.5%～1.0%。

The residues of Cordyceps militaris culture medium（hereafter be shorted as residual culture medium） were supplemented into basal diet at seven levels of 0.25%,0.5%,1.0%,2.0%,4.0%,8.0% and 16.0%,to feed Chinese mitten crab（Eriocheir sinensis）（body weight：4.0±1.0 g） for 75 d,and to determine the growth performance and non-specific immunity,and thereafter to identify the optimal supplementation level of residual culture medium in basal diet for Eriocheir sinensis.Overall,by comparison with that of diet-fed group,the results were shown as follows：1） Significant increases（P0.05） in weight gain ratio（WGR）,condition factor（CF） and survival rate（SR）,and significant decreases（P0.05） in feed coefficient（FC） occurred when residual culture medium was added at 0.5% and 1.0% levels,while supplementations at 4.0%,8.0% and 16.0% levels caused poor growth performance except slight increase in condition factor（CF）;2） Low supplementation levels were found to modify the activities of superoxide dismutase（SOD）,lysozyme（LSZ）,acid phosphatase（ACP）,and alkaline phosphatase（ALP） in Chinese mitten crab serum and hepatopancreas,and significant activity enhancement of all these enzymes were obtained by addition at 0.5% and 1.0% levels（P0.05）,while addition dosage higher than 2.0% lead to worse non-specific immunity;3）The bacterial challenge test by injection with Aeromonas hydrophila AHJ-1 confirmed that the immune protection rates of treatment groups increased significantly,and the highest rate at 100% occurred when residual culture medium was supplemented at 0.5% level.Our experiments suggested that the optimal supplementation level of residual culture medium for feeding Chinese mitten crab ranged from 0.5% to 1.0%.