营养对种公牛性发育和繁殖力的影响研究进展

Research Progress on Effects of Nutrition on Sexual Development and Fertility of Breeding Bulls

近年来基因组选择的广泛应用意味着用于人工授精的潜在父本比通过传统后代测试的公牛被更早地选择,尽管这有可能通过缩短世代间隔来加速遗传增益,但它增加了提升年轻公牛繁殖潜能的需求,而公畜的生殖潜力受到精液产量和质量的限制。加强公牛早期营养可以刺激复杂的生化相互作用,促进睾丸生长发育和性成熟提前,但对精液产量的潜在影响十分有限,同时许多调节这些发育过程的神经元机制仍有待阐明。犊牛期至青春期阶段,公牛生长达到正常的体况是其饲养的目标,适当营养限制并无法逆转犊牛期营养改善带来的优势,同时强化营养的补偿性生长也不能克服前期的营养限制。普遍营养状况对成年公牛繁殖能力的影响尚不清楚,体况过肥、过瘦、临床甚至亚临床代谢性疾病无疑会影响正常的性功能。矿物质、维生素、多不饱和脂肪酸、植物性抗氧化剂补充超过一定剂量会对精液生成产生不利影响。本文就国内外种公牛营养相关文献,针对营养素及生物活性物质对种公牛性发育、繁殖力的影响做一综述,以期为生产中种公牛饲养管理和繁殖性能提升提供参考。

The widespread implementation of genomic selection in recent years has meant that sires used in artificial insemination are selected at younger ages than was previously possible through traditional progeny testing.Although this has the potential to accelerate genetic gain by reducing the generation interval,it has led to increased demand for semen from sires at a young age.However,the reproductive potential of these young bulls is limited by the quantity and quality of semen that they can produce.Enhancing early nutrition of bulls stimulates a complex biochemical interplay,enhances testicular growth and development and earlier onset of sexual maturation,there is little evidence for latent effects on semen traits post-puberty,meanwhile much of the neuronal mechanisms regulating these developmental processes remain to be elucidated.Calving-puberty of bulls to achieve normal body condition is the goal of their feeding,and proper nutritional restriction does not reverse the advantages of improved nutrition during calving,while compensatory growth with enhanced nutrition cannot overcome the nutritional restrictions of the earlier period.The effect of general nutritional status on the reproductive capacity of adult bulls is not known,although excessive body fatness,leanness,clinical or even subclinical metabolic disorders can undoubtedly affect normal sexual function.Minerals,vitamins,polyunsaturated fatty acids and plant-based antioxidant supplementation above a certain dose can have a negative effect on semen production.This paper provides a review of the literature on bull nutrition at home and abroad with regard to the effects of nutrients and bioactive substances on the sexual development and fertility of breeding bulls,with a view to providing references for the management of breeding bulls and the improvement of reproductive performance in production.