Testicular structure and spermatogenesis of short mackerel, Rastrelliger brachysoma (Bleeker, 1851) in Upper Gulf of Thailand

Abstract

Testicular structure and spermatogenesis of short mackerel, Rastrelliger brachysoma (Bleeker, 1851) (Teleostei: Scombridae) was first investigated. The testicular parenchyma was a lobular organ, which was classified as an unrestricted spermatogonial type. The classification of spermatogenetic stage could be classified into six stages based on the pattern of chromatin condensation and other characterizations at the light microscopic level. These six stages included the primary and secondary spermatogonium, primary and secondary spermatocyte, spermatid and spermatozoon. The spermatogenesis could also be classified into another four stages based on the nuclear and cytoplasmic characterizations at the ultrastructural level. Spermatogonium was the early germ cell. It underwent a series of mitotic division to reach the primary spermatocyte. Secondary spermatocyte was shown as the heterochromatin surrounding the nuclear membrane, which was rarely seen within seminiferous lobules. Stages during the spermatids differentiation comprised of the early, intermediate and late stages which are under the degree/change of chromatin condensation. Finally, the spermatozoon was revealed as the aquasperm primitive type. It was composed of an oval head without an acrosome, a short mid-piece consisting of two basal bodies (proximal and distal centrioles) and a long flagella tail without lateral fins. The axonemes of classical form with 9+2 microtubules were presented in the flagellum.

Histological and Ultrastructural Characterization of the Gonads of the Grunting Toadfish Allenbatrachus grunniens (Linnaeus, 1758) from the Pranburi River Estuary, Thailand

“…In this study, we classified the oocyte differentiation of A. grunniens into 4 phases including oogonia proliferation (Op) phase, primary growth (PG) phase, secondary growth (SG) phase, and post-ovulatory (PO) phases based on cell size, shape, folliculogenesis and histological features. The overall characteristics were similar to those observed from H. didactylus and other fishes [7,[19][20][21][22].…”

“…In other teleosts, oocyte development is usually identified along with structural characteristics of the gonads [4][5][6][7], providing useful endpoints for the Trends Sci. 2021; 18 (22): 489 2 of 14 determination of reproductive dynamics and the accurate assessment of reproductive cycles in natural and managed habitats.…”

A Review of the Macroscopic, Microscopic, and Ultramicroscopic Characteristics of Some Key Oocyte Developmental Processes in Fish Species

“…The morphological characteristics of the atretic bodies and their stages of involution, independent of cellular development stage, were summarized in the study of Miranda et al [20], as (1) initial atresia, with the disintegration of the oocyte nucleus, fragmentation of the zona pellucida, and follicular cell hypertrophy; (2) intermediate atresia, with follicular cells presenting phagocytic characteristics and ingesting the yolk; (3) advanced atresia, with numerous myelinic figures in the cytoplasm of follicular cells; and (4) final atresia, with the reduction in the number of follicular and theca cells and presence of granules of lipofuscin and granulocytes near the atretic follicle. With the current emergence of the theme of cell death pathways, studies about ovarian involutive processes in fish were brought to the spotlight again with new descriptions being made [102,108,116,[119][120][121][122][123][124]] that add and/or corroborate those morphological characteristics already proposed by Miranda et al [20].…”

Histological and histochemical studies on the ovarian development of the grass carp, Ctenopharyngodon idella with special references to atretic phenomena.

“…khalafallah and Shehata (2011) recorded this phenomena at the end of the spawning season. Senarat et al (2016) studied Rastrelliger brachysoma and categorized atretic process into previtellogenic and vitellogenic stages.…”