Abstract:
This research describes the histology of the testis and the brood pouch of
brooding and non-brooding male seahorses, Hippocampus kuda, during the
reproductive season. Various spermatogenic cells: spermatogonia, primary
spermatocytes, secondary spermatocytes and spermatids were observed in both
brooding and non-brooding males. Spermatogonia and primary spermatocytes were
found along the entire length of the testis, while secondary spermatocytes and
spermatids were found in the lumen, though no sperm were observed. Brooding and
non-brooding males showed similar percentage of spermatogenic cells. Secondary
spermatocytes were at the highest proportion, followed by primary spermatocytes,
spermatogonia and spermatids, respectively. The brood pouches of brooding and
non-brooding males were composed of outer (stratified cuboidal) and inner
(pseudostratified) epithelia. Between them, there were 3 tissue layers: outer dense
irregular connective tissue, middle smooth muscles and inner loose connective tissue
layers. The inner loose connective tissue layer was thin and highly vascularized with
large blood vessels in the brooding male while it was thick and vascularized with
capillaries in the non-brooding male. The brood pouch consisted of 5 different stages:
normal stage in non-brooding male (inner epithelium and tissue layer were thick and
contained many small blood vessels), embryo carrying stage in brooding male (the
inner epithelium seemed to be stretched), embryo released stage in brooding male
(inner epithelium and tissue layer were flat and the surface showed rupture
appearance), repair stage I in non-brooding male (inner epithelium and tissue layer
were highly digitated) and repair stage II in non-brooding male (inner epithelial cells
had become increased in size and inner tissue layer was filled with loose connective
tissue).