Natural infestation of an anchor worm, Lernaea sp. in cage culture of Asian Seabass, Lates calcarifer juveniles and its control using an anti-parasitic drug, emamectin benzoate

Abstract

Parasitic infestations and their control programmes are one among the challenges to be considered the most signi cant in aquaculture. A parasitic infestation was studied elaborately in Asian Seabass, Lates calcarifer juveniles with clinical signs, post-mortem ndings, morphological and molecular identi cations. In addition, those sh were also treated with emamectin benzoate (EMB) @ 50 µg kg -1 of sh body weight (BW) d -1 for 10 consecutive days under the controlled wet lab facility by feeding through the medicated feed at 4% BW. Results showed that the parasitic prevalence, parasitic intensity (PI) and mortality were 45.5%, 8.17 ± 0.15 per sh and 40% over a period of one week in that existing cage culture. The parasite was identi ed as a crustacean bloodsucker, anchor worm Lernaea sp. and EMB was found to be 100% effective with signi cant reduction in PI over a period of 10 days with improved survival rate of 90% against the untreated group. Infested but treated group revealed substantial haematological improvement in parameters such as RBC, WBC, Hb, PCV, large lymphocytes, small lymphocytes and total lymphocytes (P < 0.01). Similarly, comparative histopathology of vital organs also revealed no discernible lesions between the healthy and treated sh juvenile as compared to that of infested untreated group. Hence, EMB can be used to control the Lernaea sp. infestation in Asian Seabass.

Effect of the infection of the mugilid fish Planiliza subviridis with the copepod Ergasilus rostralis: A haematological study

“…The reduction in values of Hb%, PCV and RBCs of the infected fishes in the present study was also noticed in fishes naturally or experimentally infected with some vibrios (Anderson & Conroy, 1970;Harbell et al, 1979), with other bacterial agents (Iwama et al, 1986), with naturally infection with protozoan parasites (Smirnova, 1970;Joshi, 1982;Hoffmann & Lommel, 1984) or with helminth parasites (Radhriskrishnan et al, 1983) or with crustacean parasites (Ananda Raja et al, 2020;Ananda Raja et al, 2023).…”

Visualization of poikilocytosis as an emerging erythrocytic biomarker for fish health assessment

“…Clarias batrachus, Channa punctatus, and Wallago attu [182] Cryptobia salmositica, Lernea sp. Hemorrhagic anemia Immature erythrocytes Lates calcarifer [183] Tetracapsuloides bryosalmonae Chronic normocytic hypochromic anemia…”

In vitro and in vivo action of turmeric oil (Curcuma longa L.) against Argulus spp. in goldfish (Carassius auratus)

“…The aquaculture industry encompasses significant global economic value and can generate substantial revenues for fish growers. Nevertheless, aquaculture operators will encounter a significant challenge in the form of diminished fish production and substantial economic losses resulting from a heightened mortality rate associated with parasites and disease outbreaks in fish farming ( Tavares-Dias and Martin, 2017 ; Ananda Raja et al , 2020 , 2022 , 2023 ). Ectoparasites are the predominant parasites affecting fish, as they are known to infest nearly the whole culture system.…”

“…Malachite-green/formalin mixture, trichlorfon, emamectin benzoate, and organophosphate are the main chemicals used to reduce the number of parasites and/or treat diseases in fish; however, these chemicals could lead to negative situations for animals and their surroundings, which prompted drug resistance and negatively impacted the environment ( Hakalahti-Sirén et al , 2008 ; Das et al , 2018 ; Ananda Raja et al , 2020 , 2022 ; Thakur et al , 2022 ; Ananda Raja et al , 2023 ). Therefore, alternative antiparasitic treatments derived from medicinal plants, such as plant extracts and essential oils, may be preferable to conventional chemical treatments due to their efficacy, biodegradability, environmental friendliness, and cost-effectiveness ( Kumar et al , 2012 ).…”