Probiotic effects of mixture of Groenewaldozyma salmanticensis and Gluconacetobacter liquefaciens on growth and immune responses in Paralichthys olivaceus

Abstract

Significance and Impact of the Study: This study is unique in revealing that a diet mixture of yeast, Groenewaldozyma salmanticensis and bacterium Gluconacetobacter liquefaciens can enhance growth, innate immunity and diversity of microbial community including dominant species in the olive flounder. All these indicate that the diet mixture could function as a potential antibiotic replacer in one of the most commercially important fisheries in South Korea. AbstractThis study was performed to evaluate the effects of dietary probiotics on growth, non-specific immune responses and disease resistance in olive flounder, Paralichthys olivaceus. During 8 weeks, the fish were fed the five experimental diets such as a basal commercial diet (CON), oxytetracycline (OTC) and three basal diets containing Bacillus subtilis (BS), a commercial microbial product (CES) and a mixture of yeast and bacterium (PI), respectively. Fish fed all the probiotics diets and OTC showed a significantly higher growth than fish-fed CON (P < 0Á05). Fish-fed PI had a significantly higher nitroblue tetrazolium activity, whereas fish-fed CES showed a higher lysozyme level (P < 0Á05). A 7-day challenge test also showed that fish-fed PI had a cumulative survival rate equivalent to that of fish-fed OTC (P < 0Á05). Moreover, the diet (PI) appeared to increase the diversity of microbial community in the fish. All these results suggest that the probiotics diet could function as a potential antibiotic replacer in the olive flounder.Values are mean AE SD from triplicate groups; values with same superscripts are not significantly different (P > 0Á05). ‡ WG, weight gain = (final wtÀinitial wt) 9 100/initial wt. § SGR, specific growth rate = (loge final wtÀlog e initial wt) 9 100/days. ¶ FE, feed efficiency = (wet wt gain/dry feed intake) 9 100. ** PER, protein efficiency ratio = wet weight gain/protein intake. † † SR, survival rate = (total fishÀdead fish)/total fish 9 100. ‡ ‡ HSI, hepatosomatic index = liver weight 9 100/body weight. § § VSI, viscerosomatic index = (viscera wt/body wt) 9 100. ¶ ¶ CF, condition factor = (fish wt/fish length 3 ) 9 100.

Maximum levels of cross‐contamination for 24 antimicrobial active substances in non‐target feed. Part 12: Tetracyclines: tetracycline, chlortetracycline, oxytetracycline, and doxycycline

“…Doses of 400 and 600 mg oxytetracycline/kg feed were tested in two studies with African catfish (Adeniyi et al (2018) and Adeniyi ( 2020)). In all other studies the concentrations tested were higher: 2,500 mg oxytetracycline/kg feed for African catfish (Sanchez-Mart ınez et al ( 2008)), 4,000 mg oxytetracycline/ kg feed for Nile tilapia (Won et al (2017)) and for rainbow trout (Won et al (2020); and 5,000 mg oxytetracycline/kg feed for rainbow trout (Park et al (2016a)), for starry flounder (Park et al (2016b)) and for olive flounder (Rhee et al (2020)).…”

“…In the study of Rhee et al. ( 2020 ), a total of 300 juvenile olive flounder ( Paralichthys olivaceus ), 27 g BW, were distributed in 15 thanks in groups of 20 animals and allocated to 5 treatments (3 replicates/treatment). The diet was either not supplemented (control) or supplemented with different treatments.…”

“…( 2016b )) and olive flounder (Rhee et al. ( 2020 )). Another study (Trushenski et al., 2018 ) used four species of aquatic animals – channel catfish, hybrid striped bass, Nile tilapia and rainbow trout.…”

“…( 2016a )); and with olive flounder, 5,000 mg oxytetracycline/kg feed (Rhee et al. ( 2020 )). Thus, the levels that had promoting effects on performance parameters were very variable and no specific conclusion can be drawn on dose‐related effects.…”

“…The effect of oxytetracycline as a growth promoter or yield-enhancer was confirmed in nine studies. In more detail, the following levels revealed a positive effect: with African and channel catfish, 30 mg oxytetracycline/kg feed (Olusola et al (2020)), 400 mg oxytetracycline/kg feed (Adeniyi et al (2018)), 600 mg oxytetracycline/kg feed (Adeniyi (2020)) and 2,500 mg oxytetracycline/kg feed (Sanchez-Mart ınez et al ( 2008)); with Nile tilapia, 100 mg oxytetracycline/kg feed (Reda et al (2016)), 200 mg oxytetracycline hydrochloride/kg feed (corresponding to 186 mg oxytetracycline/kg feed) (El-Sayed et al ( 2014)) and 4,000 mg oxytetracycline/kg feed (Won et al (2020)); with rainbow trout, 5,000 mg oxytetracycline/kg feed (Park et al (2016a)); and with olive flounder, 5,000 mg oxytetracycline/kg feed (Rhee et al (2020)). Thus, the levels that had promoting effects on performance parameters were very variable and no specific conclusion can be drawn on dose-related effects.…”