摘要
葡聚糖和海藻多糖是两类常用的饲料添加剂,但关于二者作用效果的差异迄今报道较少。本研究在饲料中分别添加β-葡聚糖以及岩藻多糖,比较了二者对凡纳滨对虾(Litopenaeus vannamei)幼虾的生长、非特异性免疫及对副溶血弧菌(Vibrio parahaemolyticus)抗病力的影响。研究分别设置了添加酿酒酵母(Saccharomyces cerevisiae)和裸藻(Euglena gracili)来源的β-葡聚糖以及巨藻(Macrocystis pyrifera)来源的岩藻多糖3个处理组(分别记为YG、MG和AP),饲料中添加浓度为0.65 g/kg,以商品饲料作为对照组(DZ),每个处理组分别设置5个生物学重复,对虾的初始体质量为(1.26±0.02)g,养殖周期为42 d。养殖实验结束后,进行为期14 d的副溶血弧菌攻毒实验。研究表明,各处理组对虾的养殖存活率均在90%以上,其中YG、MG和AP组存活率均显著高于对照组(P<0.05)。YG组对虾的末体质量和特定生长率显著高于对照组(P<0.05),各处理组对虾的饲料效率和消化率显著高于对照组(P<0.05)。与对照组相比,添加β-葡聚糖以及岩藻多糖均可不同程度提高对虾血清碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、总一氧化氮合酶(T-NOS)、溶菌酶(LZM)、过氧化物酶(POD)、超氧化物歧化酶(SOD)的活性、以及总抗氧化能力(T-AOC)和酚氧化酶(PO)含量。各处理组比较,以YG和MG组效果最佳,AP组次之。各处理组对虾肝胰腺LGBP、SOD、HSP70和proPO基因的相对表达量均显著高于对照组(P<0.05),β-葡聚糖添加组对虾LGBP、SOD、和HSP70基因的相对表达量均显著高于岩藻多糖添加组(P<0.05)。各处理组对虾的肝胰腺Imd、Relish和Toll基因的相对表达量均显著高于对照组(P<0.05),3个处理组之间未见显著差异。在mTOR信号通路中,β-葡聚糖添加组对虾肝胰腺中TOR、elF4E2、elF4E1α和4EBP基因表达水平显著高于对照组(P<0.05),岩藻多糖添加组TOR和elF4E2基因表达水平显著高于对照组(P<0.05)。副溶血弧菌攻毒实验表明,添加不同来源β-葡聚糖均能一定程度提高对虾存活率,其中以酵母来源组效果最佳(P<0.05)。研究结果表明,饲料中适当添加β-葡聚糖和岩藻多糖均能不同程度地提高凡纳滨对虾的生长性能、免疫能力和抗病力,其中以添加酵母来源β-葡聚糖的总体效果最佳。
Polysaccharideβ-glucan and algal polysaccharides are two prevalent feed additives,yet comparisons of their effects are scarcely reported.In this investigation,we explored the impacts of feeds supplemented withβ-glucan and fucoidan,respectively,on the growth,non-specific immunity and resistance to Vibrio parahaemolyticus infection of juvenile shrimp,Litopenaeus vannamei.β-Glucan from Saccharomyces cerevisiae(brewer's yeast)(YG)and Euglena gracilis(MG)and fucoidan from Macrocystis pyrifera(AP)were supplemented at a concentration of 0.65 g/kg feed,and a commercial feed(DZ)served as the control,five replicates each treatment.The shrimp individuals,initial mean body weight(1.26±0.02)g,were fed with these diets for 42 days.And then challenged with V.parahaemolyticus for 14 days.Results indicated that shrimp survival rate exceeds 90%among all diets,and that of YG,MG and AP significantly higher than that of control(P<0.05).YG exhibited significantly higher final weight and specific growth rate than control(P<0.05).Feed efficiency and digestibility were notably superior among all diets(P<0.05).Compared to the control,β-glucan and fucoidan supplementation significantly elevated the activity of alkaline phosphatase(AKP),acid phosphatase(ACP),total nitric oxide synthase(T-NOS),lysozyme(LZM),peroxidase(POD)and superoxide dismutase(SOD),total antioxidant capacity(T-AOC),and phenoloxidase(PO)content in shrimp serum.YG and MG demonstrated the most pronounced effects,which was followed by AP.Relative expression abundances of LGBP,SOD,HSP70 and proPO in shrimp hepatopancreas was significantly higher among all diets than those of control(P<0.05),andβ-glucan supplementation caused higher expression of LGBP,SOD and HSP70 than fucoidan supplementation(P<0.05).Expression abundance of Imd,Relish and Toll in hepatopancreas was significantly upregulated among all diets(P<0.05),and such upregulation was similar among each other.Along the mTOR signaling pathway,β-glucan supplementation significantly increased the expression of TOR,eIF4E2,eIF4E1αand 4EBP in hepatopancreas compared to control(P<0.05)while fucoidan supplementation significantly upregulated the expression of TOR and eIF4E2(P<0.05).V.parahaemolyticus challenging revealed thatβ-glucan supplementation varied in improving shrimp survival rate among its sources with yeast-comingβ-glucan exhibited the most favorable effect(P<0.05).Our findings imply that appropriate incorporation ofβ-glucan and fucoidan into feed can enhance the growth performance,immunity and disease resistance of against L.vannamei with the benefit of yeast-comingβ-glucan the most comprehensive.
作者
田相利
文湘海
罗凯
杨子昕
王德皓
王路平
刘剑锋
范瑞用
Tian Xiangli;Wen Xianghai;Luo Kai;Yang Zixin;Wang Dehao;Wang Luping;Liu Jianfeng;Fan Ruiyong(Key Laboratory of Mariculture(Ocean University of China),Ministry of Education,Qingdao 266003,China;Qingdao Ruizi Marine Engineering Research Institute Company Limited,Qingdao 266408,China)
基金
国家重点研究发展计划项目(2023YFD2401705,2020YFD0900200)资助。
