Resumen

VARGAS-VELAZQUEZ, Anahy Danae  y  JIMENEZ-SEVERIANO, Héctor. Morphometric study of the epididymes during the postnatal development in Barbados Blackbelly ram lambs. Rev. mex. de cienc. pecuarias [online]. 2016, vol.7, n.1, pp.53-68. ISSN 2448-6698.

To characterize the development of the epididymides, Barbados Blackbelly ram lambs were castrated at birth and every three weeks until wk 21 (n=4 to 6 per group). The individual epididymal weight was recorded; the three anatomical regions (caput, corpus and cauda) of the left epididymis were weighed, and samples taken for morphometric studies. The percentage of tubular tissue was calculated, as well as the tubular diameter, the width and area of the muscular layer, the height and area of the epithelium, and the diameter and area of the tubular lumen. Data were analyzed to determine differences among the anatomical regions and ages. The greatest growth of the whole organ was observed between 9 and 18 wk; the cauda started developing earlier than the other anatomical regions; the cauda was heaviest between birth and wk 12, but from 15 to 21 wk the caput and cauda weights were similar to each other. Overall, tubular diameter, width and area of the muscular layer, and luminal diameter and area were greatest in the cauda epididymidis. The epithelium height was greatest in the cauda until wk 9, but the situation reversed from wk 12 onwards. According to previous information for this breed, cauda started developing before the increase of circulating testosterone concentrations, and before the seminiferous tubule lumen appeared, whilst the caput and corpus development coincided temporally with the increase of testicular steroidogenic capacity and tubular fluid secretion. Such findings suggest differential requirements of endocrine and lumicrine stimulation for the normal development of the various anatomical regions of the epididymis.

Palabras llave : Epididymis; Sexual development; Tropical sheep; Blackbelly lambs.