黄芪多糖微胶囊制备及对刺参抗病力的影响

Preparation of astragalus polysaccharides microcapsule and its effects on disease resistance in sea cucumber Apostichopus japonicas

以黄芪多糖为芯材,海藻酸钠为壁材,采用苯酚-硫酸比色法,测得微胶囊的载药量为108mg/g;包埋率为85.7%。以初始体重为30.00±1.00g的刺参为研究对象,在室内循环水系统中进行连续35d的饲喂实验;以基础饲料为对照组,在基础饲料中分别添加3%空白微胶囊和1%、3%和5%黄芪多糖微胶囊(实验组1～4);饲喂实验结束后,通过注射刺参腐皮综合征致病菌灿烂弧菌Vibrio splendidus进行刺参攻毒实验。攻毒后14d内,实验组3和实验组4的累计发病率分别为13.33%和12.22%,均显著低于对照组、实验组1和实验组2(分别为40.00%、37.78%和32.22%)(P<0.05);实验组3和实验组4的累计发病率差异不显著(P>0.05);而实验组2累计发病率也显著低于对照组(P<0.05),但是对照组与实验组1、实验组1与实验组2之间累计发病率差异均不显著(P>0.05)。由此可知,添加3%和5%黄芪多糖微胶囊可以提高刺参的非特异性免疫力和抗病力,对刺参的免疫保护率可分别达到66.67%和69.44%。

Using astragalus polysaccharides as the core material,sodium alginate as the wall material,a spray coagulation bath method was developed for preparation of astragalus polysaccharides microcapsules,which are uniform particles at the sizes of 100～150 μ m and insoluble in water.Through phenol-sulfuric acid colorimetry,the drug loading of the microcapsule was measured as 108mg /g,and the embedding rate was 85.7%.A 35-d feeding experiment was conducted on sea cucumbers to evaluate the effects of astragalus polysaccharides microcapsules on resistance against Vibrio splendidus.The basal diet was used as control.Four practical diets were supplemented with 3% blank microcapsule and 1%,3%,and 5%astragalus polysaccharides microcapsule,respectively（Treatment 1～4）.Each diet was randomly allocated to four groups of sea cucumber cultured in 200Lfiberglass indoor tanks with circulating seawater and constant aeration.Each tank was stocked with 30sea cucumbers（initial average weight 30.00 ±1.00g）.After 35days of feeding with microcapsules or control diet,every group of sea cucumbers were injected into the body wall with 10 9 CFU /ml live V.splendidus bacterial stock solution at a dose of 0.1ml per sea cucumber（based on data of 10-day LD50pre-test）.Sea cucumbers in Treatment 3and 4showed significantly lower accumulative mortality than the control,or Treatment 1or 2（P〈0.05）,and no significant difference was observed between Treatment 3and 4（P〈0.05）.Significant difference was also observed between Treatment 2and the control（P〈0.05）,but no significant difference was observed either between the control and treatment 1,or between treatment 1and 2（P〈0.05）.According to these results,the oral administration of astragalus polysaccharides microcapsules to A.japonicus at a dose of 3% or 5%enhances the immunity as well as increases disease resistance,and the protective rate may reach 66.67%and 69.44%.