Efficiency of the Spermatogenesis in Zebu Bulls (bos taurus indicus)

Abstract

The objective of the research was to evaluate the efficiency of the spermatogenesis through the morphology of the testicular parenchyma in bulls of different zebu breeds. We used testicular fragments from bull of the breeds Nelore (n = 10), Polled Nelore (n = 6), Gyr (n = 5), Guzerat (n = 5) and Tabapuã (n = 5). The tissue was perfused with Karnovsky solution, included in glycol methacrylate and stained with toluidine blue-sodium borate 1%. Animals of the Nelore breed presented higher population of primary spermatocyte in pre-leptotene/leptotene (38.30) and in pachytene (38.14) and round spermatids (113.30), higher yield of spermatogonia mitosis (21.2) and higher daily spermatic production per gram of testicular parenchyma (32.8 × 10(6) ) than those from breeds Gyr, Guzerat and Tabapuã and higher general yield of spermatogenesis (62.4) than breeds Gyr and Tabapuã. There was no significant difference in any of the evaluated parameters between breeds Nelore and Polled Nelore. The rate of Sertoli cells did not vary between the studied breeds. Apparently, the genetic selection applied to the breeds has been improving the yield in the spermatogenic process by decreasing cellular loss, although it did not increase the support capacity of the Sertoli cells.

Functional Morphology of the Spermatogenesis of Gir Bulls

“…In the present study, Sertoli cell and spermatogonia populations showed few variations between the animals evaluated. The average number of Sertoli cells observed was four per seminiferous tubule cross-section during stage 1 of CES and in the mean number of spermatogonia cells was two per cross-section, which were similar to the numbers observed as general averages by Andreussi et al [2] in the Nelore, Nelore mocho, Gir, Guzerá, and Tabapuã breeds, in addition to by Dias [35]. However, with the progression of cell differentiation in spermatogenesis it is possible notice differences between the numbers of spermatocytes in preleptotene/leptotene, pachytene and rounded spermatocytes between the two studies mentioned above, i.e.…”

“…However, with the progression of cell differentiation in spermatogenesis it is possible notice differences between the numbers of spermatocytes in preleptotene/leptotene, pachytene and rounded spermatocytes between the two studies mentioned above, i.e. the final yield in spermatogenesis is different between the breeds, with the Nelore breed producing the greatest final spermatogenesis yield [2]. On the other hand, Aguiar et al [36] Results published in rats [31] differ from those observed in bulls in the present study.…”

“…Moreover, the dominant taurine genetics were challenged by huge problems with endo-and ecto-parasites, causing great concern to rural producers. With this scenario came the need to import cattle of Indian origin, which is rustic and better adapted to the tropical environment [1] [2].…”

Testicular Histomorphometric Evaluation of Zebu Bull Breeds

“…This genetic improvement can also be observed in the increased scrotal circumference of selected herds (Viu et al 2006;Martins et al 2011;Pinho et al 2013). The use of the scrotal circumference as the main parameter for the selection of bulls for breeding involves selecting the animals with higher sperm production and an increased testicular volume, which directly implies changes in the functional morphology of this organ and justifies the need for periodic updates of these measurements to characterize the evolution of the morphometric indexes of the testicular parenchyma (Unanian et al 2000;Andreussi et al 2013).The volumetric proportion of Leydig cells in the intertubular tissue and the quantitative parameters directly related to the seminiferous tubule, such as the tubule diameter, the thickness of the seminiferous epithelium and the tubule length (total length and length per gram of testicular parenchyma), are positively correlated with spermatogenic activity, providing information regarding the level of spermatogenic activity and constitute indicators of this activity in investigations involving testicular function (França and Russell 1998;Paula et al 1999). Despite the great importance of zebu cattle in tropical regions, there are few published studies on the process of spermatogenesis in these animals.…”

Influence of racial crossing on testicular structure and spermatogenesis in sheep Santa Inês and crossbred Santa Inês and Dorper

“…There are studies such as Maia et al (2011), which trace a comparative study of the quality of semen in sheep, but without addressing the morphological aspects. In cattle, however, Andreussi et al (2014) developed this type of comparative study, and they found differences when evaluating the morphology of testis and spermatogenic yield between five Zebu cattle breeds used in Brazil (Nelore, Polled Nelore, Gir, Guzerá, and Tabapuã).…”