Open AccessNatural dietary additive yellow loess as potential antibiotic replacer in Japanese eel, Anguilla japonica : Effects on growth, immune responses, serological characteristics and disease resistance against Edwardsiella tarda
Author(s) -
Lee S.H.,
Lee Y.K.,
Katya K.,
Park J.K.,
Bai S.C.
Publication year - 2018
Publication title -
aquaculture nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.941
H-Index - 79
eISSN - 1365-2095
pISSN - 1353-5773
DOI - 10.1111/anu.12641
Subject(s) - edwardsiella tarda , biology , oxytetracycline , lysozyme , japonica , food science , antibiotics , zoology , feed additive , amoxicillin , microbiology and biotechnology , fish <actinopterygii> , fishery , botany , biochemistry , broiler
The present experiment was conducted to evaluate the efficacy of an additive derived from the nature as an alternative of dietary antibiotic in Japanese eel, Anguilla japonica . Six experimental diets were formulated to contain no antibiotics or additive (yellow loess/ YL ) (control/ CON ), three graded levels of yellow loess at 5 ( YL 5 ), 10 ( YL 10 ) and 20 g/kg ( YL 20 ), oxytetracycline at 5 ( OTC ) and amoxicillin at 10 g/kg amoxicillin ( AMX ) of diet. Weight gain ( WG ) and specific growth rate ( SGR ) from fish fed CON or YL 5 diets were significantly lower than those of fish fed YL 20 or OTC diets. Among non‐specific enzyme, lysozyme activity of fish fed YL 20 , OTC or AMX was detected to be significantly higher than that from fish fed CON or YL 5 diets, whereas superoxide dismutase ( SOD ) activity of the fish fed CON was significantly lower than that for fish fed other experimental diets. Challenge test with bacteria, Edwardsiella tarda, showed improved disease resistance among the fish fed different levels of natural additive without any statistical difference from those fed antibiotics ( OTC and/or AMX ) supplemented diets. Therefore, these results demonstrated the potential of natural feed additive, yellow loess to replace oxytetracycline and/or amoxicillin in Japanese eel, A. japonica .