Testicular echotexture is not a viable method to indirectly evaluate the spermatogenic parameters in Nelore bulls

Resumo

The objective of this study was to evaluate the testicular echotexture of Nelore bulls and to correlate it with spermatogenic parameters. Forty one bulls aged 3-5 years, with body weight of 510.2 ± 21.61 kg were selected for the study. The animals were subjected to ultrasonography, using a portable device coupled with a linear transducer at a frequency of 7.5 MHz. Immediately afterwards they were castrated and the testicular tissue was treated with Karnovsky fixative. Next, the fragments were embedded in glycol methacrylate and stained with toluidine blue–1% sodium borate solution. The average pixel intensity in the testicular parenchyma was determined for 1,600-mm2 surface sections. The right and left testicles and the area between the two testicles resulted in average pixel intensities of 105.22 ± 13.58, 107.95 ± 12.82, and 106.59 ± 11.43, respectively. The efficiency coefficient of spermatogonial mitosis was 19.74; meiotic index was 2.63, and overall yield of spermatogenesis was 52.0. No correlation (P>0.05) was observed between testicular echotexture and any of the measured morphometric parameters. These results suggest that testicular echotexture was not a viable method for the indirect analysis of cellular population in the seminiferous epithelium, intrinsic spermatogenic performance, or the Sertoli cell index in Nelore bulls.