Projects / Programmes
Immunocastration as androgen-deprivation method and its effect on physiological response in early and late sexual development phase of pigs
| Code |
Science |
Field |
Subfield |
| 4.02.00 |
Biotechnical sciences |
Animal production |
|
| Code |
Science |
Field |
| B400 |
Biomedical sciences |
Zootechny, animal husbandry, breeding |
| Code |
Science |
Field |
| 4.02 |
Agricultural and Veterinary Sciences |
Animal and Dairy science |
immunocastration, androgen deprivation, reproductive organs, physiological response, pigs
Researchers (1)
| no. |
Code |
Name and surname |
Research area |
Role |
Period |
No. of publicationsNo. of publications |
| 1. |
33232 |
PhD Nina Batorek Lukač |
Animal production |
Head |
2018 - 2021 |
228 |
Organisations (1)
Abstract
Pig production industry in European Union (EU) faces the challenge of ending with the practice of pig castration in 2018 due to the welfare issues raised concerning surgical castration without pain relief. Presently the two most viable alternatives are fattening of intact males, and fattening of pigs vaccinated against gonadotropin releasing hormone (GnRH). The latter is a relatively novel approach, as this androgen deprivation method, also called immunocastration, has been available in EU only since 2009, and seems to be of particular interest for the situations which demand raising pigs to higher age and weight. Still, the immunocastration is rarely applied on pigs beyond standard slaughter weight and consequently the majority of available data on immunocastration implies to a standard vaccination protocol, which leads to the effective immunisation prior the onset of puberty. Thus, a large gap of knowledge about physiological response and the consequences for pork production exists for older category of pigs, intended for high quality meat products, but can be used also for males that were left entire for other purposes. Therefore, the main objective of the proposed project is to gain knowledge about physiological effects of androgen deprivation in early or late sexual development phase (maturing and adult boars), using different immunocastration protocols (i.e. emphasis on pork production situations with older and heavier pigs). It is hypothesized that the physiological effects of androgen deprivation differ, if being applied in early or late stage of sexual development, which we will try to elucidate with the proposed project and explain the mechanisms involved. Effects on reproductive function, histological and immuno-histochemical structure of testicular tissue, expression of the second isoform of GnRH (GnRH2) and its receptors in testes, level of steroid and metabolic hormones and body composition, with emphasis on fat deposition will be studied. Moreover, the project aims to provide an answer regarding the need for third vaccination when the delay between V2 and slaughter is very long. It is hypothesized that GnRH2 (e.i. intratesticular increase in GnRH2 expression) is responsible for restoration of reproductive function in immunocastrated boars observed in some studies. Different vaccination protocols which will be studied, in particular the time elapsed between effective vaccination and slaughter, will also provide the answers regarding the clearance rate of boar taint substances and development of fat tissue. Additionally, relationship between key boar taint compounds, concentrations of steroid hormones, backfat thickness, fatty acid composition and oxidative stability of fat and meat tissue will be investigated, as it is hypothesized, that polyunsaturated fatty acids are positively correlated with the level of androstenone and that short-chain fatty acids could also contribute to boar taint.
Significance for science
Raising boars brings many benefits compared to other alternatives to surgical castration without pain relive. However, due to the high risk of sexual odour (boar taint), rearing of boars for pork is not an option in the case of fattening to higher slaughter age and weight (required for high quality meat products). Similarly, the problem of boar taint limits the use of boars after the performance test or finished AI service by the meat industry, which is an important economic loss. Moreover, it represents also animal welfare issue if these boars are physically castrated at this age, despite being under anaesthesia and analgesia. In these cases, an androgen deprivation method that uses natural immune system of pig for achievement of castration-like effect, also called immunocastration, would be an alternative to classical surgical castration which has been criticised in recent years from the animal welfare point of view. Although the vaccine has been registered in EU for some time now and proven efficient to avoid boar taint in pigs intended for fresh meat market, its use in alternative pig production systems/situations has rarely been investigated, but would be of high economical relevance if applied. It seems practically the only solution (at present) for heavy pig production (i.e. situations with prolonged fattening of pigs) in the case of a ban on physical castration. Thus the main objective of the proposed project is to better understand the underlying mechanisms and physiological effects of androgen deprivation in maturing and adult boars, using different immunocastration protocols (i.e. emphasis on pork production situations with older and heavier pigs). Although the immunocastration and its impacts for pork production has lately been subject of many studies, the originality of the proposed research is in its usage in advanced stage of sexual development for which the information is scarce. Effects on reproductive function, histological and immuno-histochemical structure of testicular tissue, expression of GnRH2 and its receptors in testes, level of steroid and metabolic hormones and body composition, with emphasis on fat deposition will be studied. Additionally, relationship between key boar taint compounds, concentrations of steroid hormones, backfat thickness, fatty acid composition and oxidative stability of fat and meat tissue will be investigated. In particular, the study on the expression of GnRH2 and its receptors in testes as related to different timing of immunocastration represents a novel research direction not only interesting for pork production but also for reproductive medicine as unlike man and some other mammals (e.g. chimp, sheep and bovine) swine has functional type II GnRH receptor. So besides the relevance of the proposed studies for the benefits of pig production sector, the basic research of the physiological consequences of immunocastration may importantly contribute to the body of knowledge needed in the treatment of prostate cancer with androgen deprivation therapy in men.
Significance for the country
Raising boars brings many benefits compared to other alternatives to surgical castration without pain relive. However, due to the high risk of sexual odour (boar taint), rearing of boars for pork is not an option in the case of fattening to higher slaughter age and weight (required for high quality meat products). Similarly, the problem of boar taint limits the use of boars after the performance test or finished AI service by the meat industry, which is an important economic loss. Moreover, it represents also animal welfare issue if these boars are physically castrated at this age, despite being under anaesthesia and analgesia. In these cases, an androgen deprivation method that uses natural immune system of pig for achievement of castration-like effect, also called immunocastration, would be an alternative to classical surgical castration which has been criticised in recent years from the animal welfare point of view. Although the vaccine has been registered in EU for some time now and proven efficient to avoid boar taint in pigs intended for fresh meat market, its use in alternative pig production systems/situations has rarely been investigated, but would be of high economical relevance if applied. It seems practically the only solution (at present) for heavy pig production (i.e. situations with prolonged fattening of pigs) in the case of a ban on physical castration. Thus the main objective of the proposed project is to better understand the underlying mechanisms and physiological effects of androgen deprivation in maturing and adult boars, using different immunocastration protocols (i.e. emphasis on pork production situations with older and heavier pigs). Although the immunocastration and its impacts for pork production has lately been subject of many studies, the originality of the proposed research is in its usage in advanced stage of sexual development for which the information is scarce. Effects on reproductive function, histological and immuno-histochemical structure of testicular tissue, expression of GnRH2 and its receptors in testes, level of steroid and metabolic hormones and body composition, with emphasis on fat deposition will be studied. Additionally, relationship between key boar taint compounds, concentrations of steroid hormones, backfat thickness, fatty acid composition and oxidative stability of fat and meat tissue will be investigated. In particular, the study on the expression of GnRH2 and its receptors in testes as related to different timing of immunocastration represents a novel research direction not only interesting for pork production but also for reproductive medicine as unlike man and some other mammals (e.g. chimp, sheep and bovine) swine has functional type II GnRH receptor. So besides the relevance of the proposed studies for the benefits of pig production sector, the basic research of the physiological consequences of immunocastration may importantly contribute to the body of knowledge needed in the treatment of prostate cancer with androgen deprivation therapy in men.
