Department of Animal Science, ESALQ - University of São Paulo, Piracicaba, São Paulo, Brazil.
Laboratory of Animal Nutrition, CENA - University of São Paulo, Piracicaba, São Paulo, Brazil.
BMC Vet Res. 2021 Nov 3;17(1):344. doi: 10.1186/s12917-021-03020-7.
The ewe lamb nutritional and physiological state interfere with the ovarian environment and fertility. The lack or excess of circulating nutrients reaching the ovary can change its gene expression. A protein deficiency in the blood caused by an Haemonchus contortus abomasal infection is detrimental to the organism's development during puberty. The peripubertal period is a time of intensive growth that requires a high level of nutrients. An essential feature controlling pubertal arousal and female reproductive potential is ovarian follicle growth activation. Protein supplementation improves the sheep's immune response to helminthic infections. We aimed to determine if supplementing protein in infected ewe lambs' diet would impact the ovarian environment leading to earlier ovarian follicle activation than in infected not supplemented animals.
We fed 18 Santa Ines ewe lambs (Ovis aries) - bred by the same ram - with either 12% protein (Control groups) or 19% protein (Supplemented groups) in their diets. After 35 days of the diet, they were each artificially infected or not with 10,000 Haemonchus contortus L3 larvae. Following 77 days of the diet and 42 days of infection, we surgically collected their left ovaries and examined their genes expression through RNA sequencing.
We found that protein supplementation in infected animals led to an up-regulation of genes (FDR p-values < 0.05) and biological processes (p-value cut-off = 0.01) linked to meiotic activation in pre-ovulatory follicles and primordial follicle activation, among others. The supplemented not infected animals also up-regulated genes and processes linked to meiosis and others, such as circadian behaviour. The not supplemented animals had these same processes down-regulated while up-regulated processes related to tissue morphogenesis, inflammation and immune response.
Diet's protein supplementation of peripubertal infected animals allowed them to express genes related to a more mature ovarian follicle stage than their half-sisters that were not supplemented. These results could be modelling potential effects of the interaction between environmental factors, nutrition and infection on reproductive health. When ovarian activation is achieved in a timely fashion, the ewe may generate more lambs during its reproductive life, increasing sheep breeders' productivity.
母羊的营养和生理状态会影响卵巢环境和生育能力。到达卵巢的循环营养物质的缺乏或过剩会改变其基因表达。由捻转血矛线虫胃感染引起的血液蛋白质缺乏会对青春期生物体的发育造成损害。围青春期是一个需要高度营养的密集生长时期。控制青春期唤醒和雌性生殖潜力的一个重要特征是卵巢卵泡生长激活。蛋白质补充可改善绵羊对寄生虫感染的免疫反应。我们旨在确定在感染的母羊羔羊饮食中补充蛋白质是否会影响卵巢环境，从而导致比未补充蛋白质的感染动物更早地激活卵巢卵泡。
我们用 12%蛋白质（对照组）或 19%蛋白质（补充组）喂养 18 只圣塔因尼斯母羊（Ovis aries）-由同一只公羊繁殖-，然后对它们进行饮食喂养 35 天后，每只羊分别用 10000 条捻转血矛线虫 L3 幼虫进行人工感染或不感染。在饮食喂养 77 天后和感染 42 天后，我们通过 RNA 测序手术采集它们的左侧卵巢，并检查其基因表达。
我们发现，在感染动物中补充蛋白质会导致与卵母细胞减数分裂激活相关的基因（FDR p 值 <0.05）和生物学过程（p 值截止值 = 0.01）上调，包括在排卵前卵泡和原始卵泡激活中。补充蛋白质但未感染的动物也上调了与减数分裂和其他过程相关的基因和过程，例如昼夜节律行为。未补充蛋白质的动物下调了这些过程，而上调了与组织形态发生、炎症和免疫反应相关的过程。
围青春期感染动物的饮食蛋白质补充使它们表达的基因与未补充蛋白质的半姐妹相比，与更成熟的卵巢卵泡阶段相关。这些结果可以模拟环境因素、营养和感染对生殖健康相互作用的潜在影响。当卵巢及时激活时，母羊在其生殖寿命期间可能会产生更多的羔羊，从而提高绵羊养殖者的生产力。
