Growth hormone on ovarian morphology of lambaris (Astyanax bimaculatus) after induced spawning

Lucas Marcon,Vivian Rocha Freitas,Nilo Bazzoli,Laércio Dos Anjos Benjamin,Elizete Rizzo

doi:10.1590/0103-8478cr20180478

Abstract

ABSTRACT: Lambari, Astyanax bimaculatus, is an oviparous, multiple-spawning fish that is reproductively active throughout the year, which makes it promising for cultivation and research. This research histologically evaluates the ovaries of lambari that have undergone artificial spawning induced with pituitary extract (control group), and the effect of growth hormone at a dose of 2 mg/g body weight (treatment group) on the subsequent process of ovarian recovery. Ovaries of fish in both the control and treatments groups were collected at 120 hours after spawning and analyzed using optical microscopy to characterize the average quantities of: follicles in different stages of development, post-ovulatory follicles, follicular atresia and granulocytes. Quantity and morphology of early and advanced primary follicles did not differ between the treatment and control groups; an important and necessary factor for ovarian recovery for subsequent spawning. There was a greater amount of granulocytes in initial atresia in the group treated with growth hormone. These results demonstrated that the administration of growth hormone may potentiate the process of ovarian recovery after induced spawning.

Highlights

Lambari, Astyanax bimaculatus (Linnaeus, 1758), is a characiform fish of the family Characidae
Different stages of follicular development were quantified in both groups, but there were no significant differences(Figure 3)
The present study found no morphological differences between the control and the treatment groups for the different stages of follicular development, confirming the pattern of follicular development typical of incertaesedis fish of the family Characidae (MARTINS et al, 2012; MARCON et al, 2017)

Summary

Introduction

Astyanax bimaculatus (Linnaeus, 1758), is a characiform fish of the family Characidae. Revisions have considered many of the 88 genera (620 species) of Characidae as “Incertaesedis”, with 86 species belonging to the genus Astyanax (LIMA et al, 2003). Several papers have reported the importance of lambari to the trophic structure of Brazilian ecosystems and their reproductive behavior in the face of environmental change (PRADO et al, 2011; MARCON et al, 2015a). Lambari is of great importance to the equilibrium of the ecosystems where they occur, namely rivers of South and Central America, and they are well represented in such ecosystems in Brazilian (CARVALHO et al, 2009; WEBER et al, 2013). Astyanax bimaculatus is an omnivorous forager and a nutritionally important species for riverine communities (CARVALHO et al, 2009).

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Discussion

Conclusion