Морфологічна структура сім'яників бугаїв-плідників зі зниженою якістю сперми та в неплідних

Abstract

За аналізом результатів проведеного гістологічного дослідження препаратів, виготовлених з сім’яників вибракуваних бугаїв-плідників з’ясували, що основною причиною зниження якості сперми та неплідності, були дистрофічні та склеротичні зміни у звивистих сім'яних канальцях сім'яників, що проявлялося руйнуванням сперматогенних клітин на різних стадіях розвитку, фіброзом і гіалінозом стінки канальців, фіброзом і лімфогістіоцитарною інфільтрацією строми сім'яника та зменшенням кількості клітин Лейдіга або їх гіперплазією.

The increase in the farm animal production is associated with the increase in productive qualities of cattle at the maximum use of the selected breeding bulls. In many cases, their rational use becomes impossible because of reproductive disorders. Statistics show that more than 20% of the breeders in domestic artificial insemination firms and breeding centers are discarded due to the loss of bull fertility and poor sperm quality associated with genetic, technological, op’erational, nutritional and environmental factors or their combinations, with subsequent deviation in the morphofunctional structure of the sex glands and physiological mechanisms of regulation of spermatogenesis. The given research is aimed at studying the morphological structure of the testicles of infertile bulls and bull-inseminators with the low-quality sperm. Genitals of the 6 discarded and slaughtered in a meat-packing plant bulls of the elite record Holstein black-and-white and red-and-white breeds, aged 4-11 years old, with an average weight of 1400 kg were used for histological studies. During the research it has been established that curved seminiferous tubules of the bulls with normal spermatogenesis have a thin basement membrane and consecutively located spermatogenic epithelium. On the inner side of the basement membrane there are spermatogonia, primary and secondary spermatocytes, single Sertoli cells, spermatids and mature sperm cells. However, some tubules have partially desquamated and randomly located spermatogenic epithelium. There is also focal Leydig’s cell hyperplasia between seminiferous tubules. In bull-inseminators with low-quality sperm seminiferous tubule profiles are viewed under the protein shell. Superficial seminiferous tubules in the state of dystrophy, decrease in the mass of the germinal epithelium cells, their discomplexation and sloughing into the lumens of the tubules have been established. In some curved seminiferous tubules cells of the germinal epithelium are necrotized. There is visible destruction of the majority of seminiferous tubules with the atrophy of the spermatogenic epithelium. Some tubules are of a smaller size, the size of others has a tendency to decreasing and their contours are often curved. On some microslides a young connective tissue around destructively altered tubules is formed which displaces the interstitial tissue that is typical of the development of sclerosis of the parenchyma of the testes. Results of the histological study of the slides with the testes of discarded bull-inseminators afford ground for the conclusion that the main reason of decrease in sperm quality and bull infertility lies in dystrophic and sclerotic changes in the curved seminiferous tubules, which affects spermatogenic cells at different stages of development, lead to fibrosis and hyalinosis of the tubule walls, causes fibrosis and lymphohysteocytic infiltration of the interstitial tissue of the testis and reduction of the Leydig’s cells or their hyperplasia.