苯甲酸在全价饲料中的抑菌效果评价

Evaluation of Bacteriostatic Performance of Benzoic Acid in Complete Feed

研究使用一种新的简便、快速、灵敏的方法来评价苯甲酸在全价饲料环境中抑菌效果。试验将不同类型全价饲料(保育料、鸡全价料、教槽料)按照1∶10与水混合,在灭菌后接种大肠杆菌K88+进行培养,在不同时间点取10、20μL和30μL(浓度分别为0、0.03%、0.30%)添加到培养皿形成多点矩阵,培养24 h后观察菌斑的形态。并通过保育料比较不同浓度的苯甲酸(0、0.08%、0.10%)和青霉素钠(0.0025%、0.0030%、0.0035%)处理组菌斑形态,考察该方法的灵敏性。结果表明:苯甲酸添加量为0.03%时,在教槽料中的体外抑菌效果优于保育料与鸡全价料;在保育料中添加0.08%苯甲酸,对大肠杆菌K88+有抑菌作用,抑菌效果与添加量成正比;当苯甲酸和青霉素钠浓度分别变化0.02%和0.0005%时,抑菌效果有明显差异,说明本方法较灵敏。综上所述,全价饲料作为细菌培养基影响了苯甲酸对大肠杆菌K88+体外抑菌效果;本研究所用方法较灵敏,可评估不同类型抑菌剂在不同类型饲料中的最适添加量,从而为畜牧业提供了切合实际生产的依据。

This study aimed to evaluate the bacteriostatic performance of benzoic acid in a complete feed environment using a new simple and sensitive method.In the experiment,different types of complete feed(pig nursery feed,chicken complete feed,and creep feed)were mixed with water according to 1∶10,inoculated with E.coli K88+after sterilization,and 10μL,20μL and 30μL(concentrations of 0,0.03%,and 0.30%,respectively)were added to the Petri dish to form a multi-point matrix at different time points,and the morphology of the plaque was observed after 24 h of incubation.Benzoic acid(0,0.08%,0.10%)and penicillin sodium(0.0025%,0.0030%,0.0035%)were included in the pig nursery feed culture medium to evaluate the sensitivity of this method.The in vitro bacteriostatic effect in the creep feed was better than that of pig nursery feed and chicken feed When the amount of benzoic acid was 0.03%.The addition of 0.08%benzoic acid to the pig nursery feed has an antibacterial effect on E.coli K88+,and the antibacterial effect is proportional to the amount added.When the concentrations of benzoic acid and penicillin sodium changed by 0.02%and 0.0005%,respectively,there was a significant difference in the number of colonies,indicating that the method was more sensitive.In summary,complete feed as bacterial culture medium may comprise or enhance the bacteriostatic effect of benzoic acid on E.coli K88+in vitro.The method used in this study is more sensitive,which can evaluate the optimal amount of different types of bacteriostatic agents in different types of feed,so as to provide a useful tool for feed industry and animal husbandry.