Department of Animal Science & Technology and BET Research Institute, Chung-Ang University, 4726 Seodong-daero, Deadeok-myon, Anseong, Gyeonggi-do, 17546, Republic of Korea.
BMC Vet Res. 2021 Nov 26;17(1):362. doi: 10.1186/s12917-021-03078-3.
Sex preselection is a desired goal of the animal industry to improve production efficiency, depending on industry demand. In the porcine industry, there is a general preference for pork from female and surgically castrated male pigs. Therefore, the birth of more females than males in a litter leads to economic benefits and improved animal welfare in the pig production industry. Our previous study suggested that the porcine semen extender (BTS) adjusted to pH 6.2 maximises the differences in viability between X-chromosome-bearing (X) spermatozoa and Y-chromosome-bearing (Y) spermatozoa without affecting sperm's functional parameters. In this study we aimed to evaluate whether the pH 6.2 extender is applicable at the farm level for increasing the number of female piglets without a decline in spermatozoa fertility. Artificial insemination (AI) was carried out with spermatozoa stored at pH 6.2 and pH 7.2 (original BTS) at day 1 and day 2 of storage. Next, the functional parameters of the spermatozoa, litter size, farrowing rate, and female-to-male ratio of offspring were determined.
Although sperm motility decreased significantly after 2 d of storage, the viability of spermatozoa was preserved at pH 6.2 for 3 d. There was no significant difference in the farrowing rate and average litter size between the group inseminated with the spermatozoa stored in (pH 7.2) and that inseminated with spermatozoa stored in acidic BTS. The percentage of female piglets was approximately 1.5-fold higher in sows inseminated on day 1 in the pH 6.2 than in the pH 7.2 group. Furthermore, although there was no significant difference in the female-to-male ratio, the percentage of female piglets born was slightly higher in the pH 6.2 group than in the pH 7.2 group on day 2.
The method optimised in our study is simple, economical, and may enhance the number of female births without any decline in spermatozoa fertility.
性别选择是动物产业提高生产效率的一个理想目标，这取决于行业需求。在养猪业中，人们普遍更喜欢来自雌性和手术去势公猪的猪肉。因此，一窝仔猪中雌性数量多于雄性会带来经济效益，并改善养猪业的动物福利。我们之前的研究表明，将猪精液稀释液（BTS）调整至 pH 6.2 可最大限度地提高携带 X 染色体（X）精子和携带 Y 染色体（Y）精子之间的活力差异，而不影响精子的功能参数。在这项研究中，我们旨在评估 pH 6.2 稀释液是否适用于农场水平，以增加母猪产仔数量，而不会降低精子的生育能力。在储存第 1 天和第 2 天，使用储存于 pH 6.2 和 pH 7.2（原始 BTS）的精子进行人工授精（AI）。接下来，确定精子的功能参数、产仔数、产仔率和后代的雌雄比例。
尽管精子活力在储存 2 天后显著下降，但 pH 6.2 下精子活力可保持 3 天。在使用储存于 pH 7.2 的精子和储存于酸性 BTS 的精子进行授精的母猪中，产仔率和平均产仔数没有显著差异。在 pH 6.2 组中，与 pH 7.2 组相比，在第 1 天授精的母猪所产的母猪比例约高 1.5 倍。此外，尽管雌雄比例没有显著差异，但在第 2 天，pH 6.2 组中出生的母猪比例略高于 pH 7.2 组。
我们优化的方法简单、经济，可以在不降低精子生育能力的情况下提高母猪产仔数量。
