Effect of immunological castration of male pigs on morphological and functional con-dition of the testicles

Changes in the priorities of the treatment of animals in the conditions of intense technology of production of livestock products are based on the necessity of wellbeing of animals. Therefore, there is a need of search for and broad introduction of generally accepted alternatives to surgery, which would use modern means of castration, particularly immunocastration. The study presents morpho-functional substantiation of practicability of using immunological castration in the conditions of industrial production of pork. At the same time, we studied immunological castration using Improvak on the morphological and physiological condition of the testicles of male pigs. The testosterone level was determined using radioimmunologic method after 2, 4, 6, 8 weeks of immunological and surgical castrations, and also in intact boars of the control group. During the slaughter, we selected biopates of the testicles in immunological castrates and pigs of the control group for histological examination. The testosterone level 2 weeks after castration was the lowest in the animals castrated using Improvak. This indicator gradually increased, and after 8 weeks was higher than in the surgically castrated pigs. In the latter, the level of testosterone gradually decreased for 8 weeks, and did not significantly change in non-castrated pigs. The last stages of spermatogenesis in immunocastrates were inhibited after the second vaccination. As a result of immunological castration, the interstitial tissue of the testicle underwent changes. Between the tubules, a spreading of the loose connective tissue was observed. Leydig cells lost hyper chromaticity of the cytoplasm and typical polygonal profile, and their functional potential decreased. This fact was confirmed by the changes in the Hertwig’s ratio. In particular, we observed decrease in the value of the nuclear-cytoplasmic ratio. There were also a time shift of mitotic cycle, low degree of differentiation of spermatogonia and rupture of the course of the subsequent stages of spermatogenesis. However, there occurred multiplication of primary spermatogonia, single cellular divisions, and in the ductus deferentes, there could be found single spermatids. Some of them formed specific cellular groups of rounded and elliptic shapes in the seminiferous tubules. These structures were absent in the testicles of the control animals. Microstructural changes in the swine after injecting Improvak were characterized by deficiency of Leydig cells, indicating absence of the normal hormonal background, as confirmed by the results of the study of testosterone level. The epithelium-spermatogenic layer was underdeveloped, and the lumens of the tubules were in some places filled with generations of spermatocytes. In some places, meiosis was observed, which also indicates insignificant functioning of the testicles. Vaccination with Improvak caused atrophy of the testicles in swine and decrease in their functional condition, allowing it to be recommended it for broader application as an alternative to surgical castration.

The effectiveness of Imrovac® in industrial pork production

The clinical efficacy of the use of immunobiological castration was studied in comparison with boars in which orchidectomy was performed by open method «on a ligature», as well as in non-castrated animals. It was found that the disadvantage of surgical castration is the risk of bleeding, the development of purulent inflammatory process (edges of the surgical wound, scrotal tissues, stump, common vaginal membrane), as well as intra- and postoperative hernias, which are accompanied by prolapse of the omentum, intestines, and bladder. The low incidence of these complications is offset by the high death rate caused by them. A relatively high level of cryptorchidism was established on the farm, among which bilateral was 27.6%. As a result of the use of immunological castration, in comparison with surgical castration, and with non-castrated boars, the average daily gains were increased, the fattening period was reduced and feed costs were reduced against the background of feed conversion increase by 14 – 27%. The use of Improvac® (Pfizer Ltd) led to better assimilation of feed, an increase in the amount of meat on the carcass, in particular, lean meat by 12 – 16%, lumbar depth, the protein content in meat and a decrease of the fat percentage and fat thickness, eliminating specific odor, and reduction in the fattening period, as well as costs for feeding. In particular, compared to non-castrated boars, the weight of chilled half carcasses increased by 1.2 times (P < 0.05). Immunological castration led to atrophy of the testicles: their weight, length and width were smaller compared to non-castrated boars, which again confirms a decrease in the level of boars’ sex hormones. It is important to use Improvac® in breeding boars that have exhausted their potential, eliminating the need to keep them for about three months to reduce their meat and lard smell. Reducing the period of disappearance of the odor of products obtained from boars led to a reduction in the cost of feeding, maintenance, and veterinary care. Production indicators justify the economic feasibility of using immunological castration with Improvac® in order to obtain additional income, given the absence of probable complications associated with the conventional surgical procedure.

Serum levels of testosterone and performance of surgical or immunocastrated beef steers

The objective of the present study was to evaluate the serum concentration of testosterone and the performance of beef steers submitted to different surgical or immunological castration strategies. Forty- eight Aberdeen Angus calves were randomly distributed in the following treatments: surgical castrated at birth; surgical castrated at weaning; immunocastrated with three doses of Bopriva® vaccine; immunocastrated with four doses of Bopriva® vaccine. The hormonal dosages were performed through ELISA Test by “In vitro” competition. The weighing and body condition score of the animals were determined at the beginning and at the end of each evaluated phase. The completely randomly experimental design was used. Data were submitted to variance analysis by F test, being the averages compared by Tukey test with α=0.05. There was an interaction between treatment and collection date (P<0.05) for the serum levels of testosterone. By occasion of the slaughter, all the animals presented a similar serum concentration of testosterone, characterizing them as castrated. Animals immunological castrated with three doses of Bopriva® presented higher daily average gain and total weight gain on finishing phase than the ones surgical castrated at weaning. The immunological castration shows a viable alternative in relation to surgical castration.