Zeng X Y, Turkstra J A, van de Wiel D F, Guo D Z, Liu X Y, Meloen R H, Schaaper W M, Chen F Q, Oonk H B, Zhang X
Isotope Research Lab, Sichuan Agricultural University, Ya'an, P.R. China.
Reprod Domest Anim. 2001 Apr;36(2):101-5. doi: 10.1046/j.1439-0531.2001.00256.x.
We have investigated, under the normal conditions of local Chinese pig farming, castration of young male pigs by vaccination with a newly developed vaccine against gonadotrophin releasing hormone (GnRH). Because of the very early onset of puberty, long fattening period and relatively harsh circumstances in Chinese pig production, an investigation of the endocrine response of Chinese breeds to this type of vaccination was of particular interest. Fifteen crossbred boars (Yorkshire x Yanan) from three different litters were randomly assigned to three groups of five animals each. The first group was immunized at 13 weeks of age with a GnRH tandem dimer OVA-conjugate in Specol and received a booster immunization 8 weeks later. The second group was injected with Specol alone and served as untreated controls. The remaining group was surgically castrated at the time of weaning (at 6 weeks of age). Pigs were fed ad libitum from weaning onwards. All animals were slaughtered at 31 weeks of age. Immunized boars had undetectable or low serum testosterone (0.09 +/- 0.12 ng/ml), low fat androstenone (0.05 +/- 0.01 microg/g) levels and very low testes weights (19.1 +/- 4.3 g). Intact controls had much higher serum levels of testosterone (9.76 +/- 4.81 ng/ml), fat androstenone levels (2.26 +/- 0.87 microg/g) and testes weights (114.3 +/- 29.41 g) at slaughter. Both the immunized and castrated group grew significantly faster than intact boars (p < 0.01). Average daily gains in immunized, castrated and intact animals were 0.69 +/- 0.08, 0.63 +/- 0.05 and 0.42 +/- 0.07 kg (mean +/- SD), respectively. The present data demonstrate for the first time that the newly developed anti-GnRH vaccine works very well under practical Chinese pig farming conditions, and can be an attractive alternative to surgical castration.
我们在中国本地猪正常养殖条件下，研究了用新开发的抗促性腺激素释放激素（GnRH）疫苗对幼龄公猪进行去势。由于中国猪生产中青春期开始非常早、育肥期长且环境相对恶劣，因此研究中国品种猪对这种疫苗接种的内分泌反应特别有意义。来自三窝不同的15头杂交公猪（约克夏×延安）被随机分为三组，每组5头动物。第一组在13周龄时用Specol中的GnRH串联二聚体OVA偶联物进行免疫，并在8周后接受加强免疫。第二组仅注射Specol，作为未处理的对照。其余一组在断奶时（6周龄）进行手术去势。从断奶起猪自由采食。所有动物在31周龄时屠宰。免疫公猪的血清睾酮水平不可检测或很低（0.09±0.12 ng/ml），脂肪雄烯酮水平低（0.05±0.01 μg/g），睾丸重量非常低（19.1±4.3 g）。完整对照在屠宰时血清睾酮水平高得多（9.76±4.81 ng/ml），脂肪雄烯酮水平高（2.26±0.87 μg/g），睾丸重量高（114.3±29.41 g）。免疫组和去势组的生长速度均显著快于完整公猪（p<0.01）。免疫、去势和完整动物的平均日增重分别为0.69±0.08、0.63±0.05和0.42±0.07 kg（平均值±标准差）。目前的数据首次证明，新开发的抗GnRH疫苗在中国实际养猪条件下效果良好，并且可以成为手术去势的有吸引力的替代方法。
