Optimal Dietary Fiber Intake to Retain a Greater Ovarian Follicle Reserve for Gilts
Optimal Dietary Fiber Intake to Retain a Greater Ovarian Follicle Reserve for Gilts
复制标题
最佳膳食纤维摄入量可保留后备母猪更大的卵巢卵泡储备
作者：
Cao, Meng;Zhuo, Yong;Wu, De
成功培育后备母猪对于可持续的生猪生产至关重要，而大多数进入种猪群的后备母猪在很小的时候就被淘汰。近年来生殖生理学研究表明，卵巢储备功能可作为提高生育年限的重要指标。因此，在本研究中，我们假设膳食纤维可以促进卵泡发育和存活。目前，尽管膳食纤维（而不是淀粉、蛋白质或饲喂量水平）可以提高后备母猪的生育力，但对于生长中的后备母猪来说，没有适当的膳食纤维摄入水平。本研究的结果表明，卵泡发育和存活对膳食纤维水平敏感。我们的研究结果揭示了膳食纤维对母猪繁殖有益作用的机制，并为通过靶向卵巢储备提高猪的终身生育力提供了营养见解。摘要近年来研究发现，母猪卵巢卵泡的激活和存活受营养传感器AMP激活蛋白激酶（AMPK）和哺乳动物雷帕霉素靶蛋白（mTOR）以及凋亡相关标志物Caspase-3、Bax和Bcl-2的调控，但它们的表达受膳食纤维的调控仍不确定。为探讨日粮纤维水平对母猪卵泡发育的影响，以及与卵泡激活和存活相关的细胞分子成分，在76头体重和日龄相近的母猪中，分别饲喂玉米-豆粕型对照日粮和其他3种日粮，在不同试验阶段分别比对照日粮多消耗50%、75%和100%的日粮纤维。在玉米-豆粕基础日粮中添加菊粉和纤维素（1：4），以提高日粮纤维含量。日粮对生长性状、年龄、体重和青春期背膘厚度无明显影响。在实验的第30天和第3个发情周期的第19天，每立方厘米卵巢组织的原始卵泡数和总卵泡数随膳食纤维水平线性增加，而不影响直径在1-3 mm之间或大于3 mm的窦卵泡的形成。这些变化与mTOR，S6，卵巢组织中细胞外调节蛋白激酶1/2（ERK 1/2）和AMPK以及Caspase-3、Bax和Bcl-2的mRNA表达。总的来说，这项研究证明了膳食纤维对母猪卵泡储备的有益影响，这为短期或长期提高繁殖能力提供了基础。
Simple Summary Successful development of replacement gilts plays a critical role for sustainable swine production, whereas most gilts entering the breeding herd are culled at a young age. Recent advances in reproductive physiology revealed that the ovarian reserve could be considered as an important target of improving reproductive span. Therefore, in the present study, we hypothesized that ovarian follicle development and survival could be enhanced by dietary fiber. Currently there is no appropriate level of dietary fiber intake for growing replacement gilts despite the fact that dietary fiber, rather than starch, protein, or feeding allowance level, could improve the fertility of gilts. Results in the present study demonstrated that ovarian follicle development and survival were sensitive to dietary fiber levels. Our results shed light on the mechanisms underlying the beneficial effects of dietary fiber on the reproduction of sows and provided nutritional insights for enhancing the lifetime fertility of pigs by targeting the ovarian reserve. Abstract Ovarian follicle activation and survival were recently found to be controlled by nutrient sensors AMP-activated protein kinase (AMPK) and mammalian target of rapamycin (mTOR) and apoptosis related markers Caspase-3, Bax, and Bcl-2, yet their expression as regulated by dietary fiber remained uncertain for gilts. To investigate the effects of dietary fiber levels on ovarian follicle development, and the cellular molecular components related to follicle activation and survival of gilts, 76 gilts with similar bodyweight and age were fed four diets, including a corn-soybean meal based control diet, or other three diets to consume 50%, 75%, and 100% more dietary fiber than the control gilts at different experimental phases. Inulin and cellulose (1:4) were added to the corn-soybean meal basal diet to increase dietary fiber content. The growth traits, and the age, bodyweight, and backfat thickness at puberty were not affected by diets. The number of primordial follicles and total follicles per cubic centimeter of ovarian tissue linearly increased with dietary fiber level at day 30 of the experiment and at the 19th day of the 3rd estrous cycle, without negatively affecting the formation of antral follicle with diameter between 1–3 mm or larger than 3 mm. These changes were associated with altered phosphorylation of mTOR, S6, Extracellular regulated protein kinases 1/2 (ERK1/2) and AMPK, and mRNA expression of Caspase-3, Bax, and Bcl-2 in ovarian tissues. Collectively, this study demonstrated a beneficial effect of dietary fiber on the ovarian follicle reserve in gilts, which provides a basis for enhancing reproduction in the short- or long-term.