Aspectos da reprodução sazonal em Phyllostomus discolor (Wagner, 1843) e Artibeus planirostris (Spix, 1823) (Mammalia: Chiroptera) no município de Vitória de Santo Antão, Pernambuco: características histomorfométricas, imunohistoquímicas e hormonais

Abstract

Information about the reproductive morphophysiology of bat species Phyllostomus discolor and Artibeus planirostris is limited, especially in northeastern Brazil. The objective was to verify the seasonal aspects in the reproduction of these species, by means of histomorphometric, immunohistochemical and hormonal parameters in the Municipality of Vitória de Santo Antão, Pernambuco. Through meteorology, dry months (September to February) and rainy months (March to August) were established. Adult males from P. discolor (n=12) - dry (n=06) and rainy (n=06) - and from A. planirostris (n=16) - dry (n=08) and rainy months were captured (n=08). 33 adult A. planirostris females were collected - inactive (n=13), pregnant (n=08), lactating (n=07) and post-lactating (n=05). In the histomorphometry of the ovaries, only the inactive ones were considered. The females of P. discolor were not considered, because the quantity captured was not sufficient for the due analyzes. After anesthesia, blood samples were obtained for testosterone (in males) and estrogen (in females). After euthanasia, the testes, the epididymis and the ovaries were collected, processed and the slides produced were subjected to analysis under optical microscopy. In the testes of P. discolor stained with the AgNOR technique, spermatocytes and spermatids showed higher averages in the parameters evaluated in rainy months. Spermatocytes and rounded spermatids showed changes in dry months. In the regions of the epididymis (caput, corpus and cauda), there were variations in the height of the epithelium, in the diameters of the tubule and lumen, and in the volumetric proportion of the epithelium and lumen in dry months; blood vessels and connective tissue showed greater changes in rainy months. The principal cells were the most abundant, followed by basal and apical cells. For A. planirostris there were pregnant females only in dry months, however females in the other reproductive stages occurred in dry and rainy months. Dosage estrogen and the presence of positive PCNA cells in the ovaries were higher in rainy months. Graaf follicles were found only in these months, whereas the corpus luteum occurred in all specimens from the dry months. In A. planirostris males, there was an increase in the average of spermatocytes, rounded and elongated spermatids in dry months; in the rainy months, there was greater activity in cell proliferation, in the number of Sertoli cells and spermatogonia. Epididymal histomorphometry indicated an increase in the height of the epithelium, in the diameters of the duct and lumen of the regions of the head and body in dry months, however the tail did not show variations. Therefore, both species showed changes in their reproductive activity with some peculiarities. Although P. discolor has shown variations in some parameters related to the dry months, and in others to the rainy months, everything indicates that this species has ample flexibility to reproduce at any time of the year. And, although the females of A. planirostris prefer to enter gestational periods in the dry months and mate in the rainy months, they have an reproductive pattern of the asazonal type, which induces the males of this species to adapt their spermatogenic, steroidogenic and epididymal activity in periods that the abiotic factors are more advantageous for the reproductive cycle of these mammals.