Effect of Graded Levels of Dietary Emamectin Benzoate on Immunity, Enzyme Activity, and Withdrawal Period in Labeo rohita Juveniles (Hamilton, 1822)

Abstract

This study was conducted to evaluate the effect of dietary emamectin benzoate (EB) levels on immune responses, serum enzyme activities, and retention of EB in muscle tissue to establish the withdrawal period in rohu, Labeo rohita juveniles (avg. wt. 18 ± 0.11 g). To ascertain this, 450 healthy L. rohita juveniles were fed with EB in graded doses viz., at 50 (1x), 125 (2.5x), 250 (5x), and 375 (7.5x) μg kg-1 of fish biomass day-1, respectively, in triplicate for 21 days through a basal feed. Upon completion of 21 days, the same experimental fish were fed with basal feed (without EB) for another 14 days to measure the retention of EB in the muscle tissue. Each 7-day interval, five fish were randomly sampled. The results showed that respiratory burst activity, myeloperoxidase activity, bacterial haemagglutination, and haemolysis activities were improved significantly ( p < 0.05 ) in 1x and 2.5x dose fed group from 7th day onwards until 14th day. Few selected enzyme activities viz., LDH and ALP were found to be significantly ( p < 0.05 ) high in the fish fed with EB at 5x and 7.5x dose compared to 1x. The LC-MS/MS study of the experimental fish discloses that EB was retained in muscle tissue at a dose-dependent manner and significantly ( p < 0.05 ) lowest level ( 0.341 ± 0.03 ppb) was retained in the fish fed with 1x dose of EB. Hence, 1x dose of EB may be adhered to treat L. rohita juveniles through feed with 14 days of withdrawal period.

Biosafety, histological alterations and residue depletion of feed administered anti-parasitic drug emamectin benzoate in golden mahseer, Tor putitora (Hamilton, 1822) as a model candidate fish for sport fishery and conservation in temperate waters

“…Even a slight appetite decrease in fish treated with 5× and 10× EB doses did not affect the growth of the golden mahseer juveniles. This finding is supported by similar studies, where the growth of fish were not affected when administered with higher EB doses through medicated feed (Julinta et al, 2020;Raja et al, 2020;Choudhary et al, 2022). Also, the toxicity study in Atlantic salmon and rainbow trout corroborate our finding, where the growth of EB treated fish were not affected as compared to control one fed with EBfree diet (Roy et al, 2000;Bowker et al, 2013).…”

“…Here, we concluded that EB residue in muscle is within the MRL, even if it is administered for three times the recommended duration of 7 consecutive days at dose of 50 μg/kg fish/day. Similar research has been conducted in different fishes from different geographical locations of the world, where adequate margin of safety of EB was reported at recommended dose (Kim-Kang et al, 2004;Whyte et al, 2011;Collymore et al, 2014;Neto et al, 2019;Julinta et al, 2020;Raja et al, 2020;Choudhary et al, 2022). In our study, the traces of Emamectin B 1a were still detected in muscle tissues of EB treated golden mahseer after 30 days post-medication, which suggests the complete withdrawal of EB require more than 30 days in golden mahseer.…”

“…The ad libitum feeding was followed to ensure the maximum feed uptake by the golden mahseer juveniles and avoiding leaching into water. In an EB medicated trial on L. rohita, fishes appeared to have consumed the feed within 15-30 min of receiving the medicated diet which indicates low or undetectable amount of EB leaching into the water (Choudhary et al, 2022). However, it was observed that the feed intake by golden mahseer was not influenced by 1× and 2× EB treatments, but there was a considerable decrease in the 5× and 10× EB treated fish, even after the medication period was over.…”

“…The toxicity of EB on rainbow trout and Atlantic salmon has been studied by various researchers in different regions and habitats (Roy et al, 2000;Stone et al, 2000;Stone et al, 2002). There are reports of EB toxicity and biosafety in common carp (Braun et al, 2008), Asian Seabass (Raja et al, 2020), Labeo rohita (Choudhary et al, 2022;Kumar et al, 2022) and Nile tilapia (Julinta et al, 2020) from Indian freshwater and brackishwater aquaculture system.…”

The potential effect of Moringa oleifera ethanolic leaf extract against oxidative stress, immune response disruption induced by abamectin exposure in Oreochromis niloticus

“…The decreased activity of alkaline phosphatase in pesticide-exposed fish may be connected to the interactions between pesticides and co-factors and regulators, as well as its inducement to cell organelle damage such as the endoplasmic reticulum and membrane transport system damage (Al-Ghanim et al 2020 ). On the contrary, the Labeo rohita juveniles fed with emamectin benzoate ≥ 250 μg kg −1 of fish biomass per day for 21 days had considerably high levels of ALP (Choudhary et al 2022 ). The marked increase in serum total protein, albumin, and globulin was recorded in O. niloticus exposed to ABM acute toxicity at 5 µg/l for 96 h (Farag and Reda 2021 ).…”