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Synergistic inhibition effects of tea polyphenols as adjuvant of oxytetracycline on Vibrio parahaemolyticus and enhancement of Vibriosis resistance of Exopalaemon carinicauda
Author(s) -
Guo Qin,
Zhang Chunyan,
Cao Qingguo,
Cai Jiahui,
Chen Hui
Publication year - 2021
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/are.15234
Subject(s) - oxytetracycline , biology , microbiology and biotechnology , vibrio parahaemolyticus , antibiotics , antimicrobial , lysozyme , tetracycline , immunopotentiator , adjuvant , vibrio , immune system , bacteria , biochemistry , immunology , genetics
Antibiotics worldwide were abused to kill all kinds of pathogens in shrimp industry, which resulted in the emergence of many drug‐resistant strains, such as Vibrio parahaemolyticus . Natural plant extracts (NPEs) as adjuvant of antibiotics offer an effective alternative to minimize the problems. We evaluated the antimicrobial activities of different combinations of eight NPEs and eight antibiotics allowed to be used in aquaculture and found tea polyphenols (TP) was the optimum adjuvant of oxytetracycline against V . parahaemolyticus . The smallest FIC index of 0.14 was obtained with the combination of 1/64 MIC TP and 1/8 MIC oxytetracycline. The combination of TP and oxytetracycline could improve the survival rate to 53.3 ± 2.74% of Exopalaemon carinicauda in vitro, higher than that in the TP or oxytetracycline group significantly. The activities of digestive enzymes (pepsin and amylase) and immune enzyme including lysozyme, alkaline phosphatase (AKP), the expression levels of cathepsin D (CatD) and Toll receptor (Toll) of E . carinicauda were up‐regulated significantly. The changes of immune parameters thereby promoted the growth and improved the immunity of E . carinicauda , which led to the increase in resistance against V . parahaemolyticus . The results showed that the synergistic inhibition mechanisms of TP and antibiotics may be involved in the immune defence process and the increased abilities of digestion. The combination could reduce the use of oxytetracycline when the better therapeutic effect was achieved.