Toxicity and antiparasitic efficacy of Mebendazole in juveniles of Mugil liza mullet

Author: Adriana Patrícia Salgado Otero (Currículo Lattes)
Supervisor: Dr Marcelo Borges Tesser
Co-supervisor: Dr Luis Alberto Romano

Abstract

The bijupirá, Rachycentron canadum is a marine fish of importance in aquaculture. Research on the ontogeny of organs and systems is scarce, and information on the thyroid tissue of the bijupira is lacking. Studies on the development of thyroid tissue are important because they provide information about their role in the larvae and thus can be used to improve breeding techniques. Therefore, the aim of this study was to describe the ontogeny of thyroid follicles in bijupirá. Bijupira larvae were collected daily from hatching to 28 dae and a new sample was collected at 53 dae. The samples were dehydrated in alcohol, included in Paraplast, made 3 μm histological cuts, rehydrated and submitted to Hematoxylin-Eosin (HE) and PAS staining. In the larvae of the 1st day after hatching (dae),the presence of a single follicle was found. Three follicles were found on the 8th day and these increased with the growth of the larva, observing up to 18 follicles on the 53th day. The diameter of the follicles and the height of the follicular cells were smaller in the 1st dae (6.83 ± 1.00 μm and 4.6 ± 001 μm), but increased from the 8th dae (24.03 ± 0.46 μm and 6.43 ± 0.46 μm,). From the 8th day onwards, reabsorption vesicles in the colloid and from the 19th and 23rd days onwards, there is an absence of colloid in some follicles and, in those that did, many vesicles were also found in the periphery, which are indicative of a active thyroid tissue. The results of this study demonstrate that the bijupira is the only pelagic species with the appearance of the follicle in the 1st dae, presenting activity at the 8th dae and being more functional from the 19th dae.

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