α-亚麻酸调节蛋用种公鸡睾丸睾酮生物合成的分子机理

α-linolenic acid (ALA) is recognized as one of the most important functional lipids, with an important function on improving sperm motility and promoting testosterone synthesis in animals. The problems of rooster reproductive performance have led to the low fertilization rate, hatching rate and poor chicken qualities, which has seriously hindered the healthy development of Chinese poultry breeding industry. Our previous preliminary studies have found that feeding ALA could promote the testosterone secretion of laying roosters and improve sperm motility. However, the mechanism behind it is not clear. We intends to combine animal and cell culture experiments to study the mechanism of ALA regulating the secretion of testosterone from the perspective of testosterone synthesis pathway. To explore the role of the related signal transduction in the process of testosterone synthesis pathway, changes of key enzyme and protein involved in the process in the level of transcription and translation, activation of transcription factors regulating the gene expression of enzyme and protein, and changes of upstream protein kinase phosphorylation levels are observed. According to the above research, we will further reveal the mechanism of ALA regulating the biosynthesis of androgen testosterone, and finally clarify the mechanism of ALA to improve reproductive performance of laying roosters. The current research will provide the logical proof and technology support for rational use of lipid resources to improve the economic efficiency of poultry breeding industry, and provide new ideas for modern animal assisted reproductive technology.

α-亚麻酸（ALA）是公认的最重要功能性脂类物质之一，具有提高畜禽精子活力和促进睾酮合成的功能。由于目前国内种公鸡繁殖质量问题，已造成种蛋受精率、孵化率低以及商品雏鸡质量差等现状，严重威胁我国家禽良种产业的健康发展。与此同时，本课题组前期研究已发现，饲喂ALA对提高蛋用种公鸡的精子活力和促进睾酮合成等繁殖性能具有积极作用，但其具体调控机理尚不清楚。本研究拟以睾酮合成途径为切入点，结合动物试验和体外细胞培养试验研究ALA对蛋用种公鸡睾酮合成的调节机制，通过研究睾酮合成过程中涉及的关键酶和蛋白在转录和翻译水平的变化，调控关键酶和蛋白的重要转录因子的活化情况以及上游蛋白激酶磷酸化水平的变化，探讨相关信号转导通路在睾酮合成过程中的作用，系统深入地揭示ALA对蛋用种公鸡睾丸睾酮生物合成的调控机理，以期为饲料中合理利用油脂资源、提高家禽良种产业经济效益提供理论支撑，为现代动物辅助生殖技术提供新思路。

α-亚麻酸（ALA）是公认的最重要功能性脂类物质之一，具有提高畜禽精子活力和促进睾酮合成的功能。目前国内种公鸡繁殖质量问题，已严重制约我国家禽良种产业的健康发展。本课题组前期研究发现，饲喂ALA对提高蛋用种公鸡的精子活力和促进睾酮合成等繁殖性能具有积极作用，但其具体调控机理尚不清楚。本研究在前期研究基础上，以睾酮合成途径为切入点，结合动物试验和体外细胞培养试验系统研究了ALA对蛋用种公鸡睾酮合成的调节机制。动物试验研究结果表明，日粮中添加ALA可显著提高蛋用种公鸡血浆生殖激素T、LH和FSH的含量。添加ALA可显著增强P450scc和StAR的mRNA表达量，同时提高了SF-1的mRNA和蛋白表达量。提示，ALA可能通过增强SF-1的表达提高P450scc和StAR的表达量，促进睾酮T的合成与分泌；针对动物试验的初步结果进行进一步深入研究，以睾丸间质细胞为体外试验研究平台，揭示ALA促进Leydig细胞睾酮合成的作用机制。研究结果表明，采用胶原酶消化与差速离心分离的方法经差速贴壁和传代纯化，成功获得高纯度原代睾丸间质细胞。40 μmol/L ALA可显著提高睾丸间质细胞睾酮合成与分泌，同时可显著增强睾酮合成途径关键酶和蛋白StAR、P450scc、3β-HSD、P450c17 mRNA表达。ALA处理后显著提高了JNK的蛋白磷酸化表达量和mRNA表达量，抑制JNK通路后，显著降低通路下游StAR、P450scc、3β-HSD、P450c17基因和SF-1 mRNA表达量。综上所述，ALA可通过激活JNK-SF-1信号通路增强下游睾酮生物合成关键基因StAR、P450scc、3β-HSD、P450c17的基因表达，促进睾丸组织睾酮的生物合成与分泌，从而提高种公鸡的繁殖性能。本研究在分子水平成功揭示了ALA对蛋用种公鸡睾酮生物合成的调控机理，为推动植物性来源n-3 PUFAs在种公鸡营养调控中的应用提供了理论支撑，也为提高动物繁殖性能的营养调控机理研究提供了新的思路和模式。