Nutritional regulation of negative feedback homeostasis in the hyothalamo-pituitary-ovarian axis of sheep and its effect on folliculogenesis

绵羊下丘脑-垂体-卵巢轴负反馈稳态的营养调节及其对卵泡发生的影响

• 批准号: BB/D018420/1
• 负责人: Rex John Scaramuzzi
• 金额: $ 64.85万
• 依托单位: Royal Veterinary College
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=BB%2FD018420%2F1
• 关键词: Nutritional; regulation; negative; feedback; homeostasis

What an animal eats has a major effect on its fertility. More specifically, if female sheep are fed a good diet just before they are mated they will produce more sets of twins than similar ewes fed poor diets. The most remarkable feature of this phenomenon is that the period of good feeding needs to last for only 3 or 4 days. The reason for the effect of good nutrition on the number of twins is put down to a stimulation of egg production in the few days leading up to mating. Why this happens is not at all clear and this research will investigate how this happens. Published studies from our team and other researchers in the field point to the increased energy content of the diet one of the most important reasons for the this effect. In sheep, the main source of this extra energy is plant carbohydrate and as a result we have turned our attention to the role of carbohydrate in our attempts to unravel the biological mechanism behind this phenomenon. Our interest in carbohydrates is based on published information mainly from Australian researchers into the so called 'lupin effect'. In short, the Australians discovered that feeding sheep a supplement of lupin grain for as little as 3 days just before mating will reliably and consistently stimulate the birth of more twins in supplemented flocks. So what is so special about lupins? Well, they have a very high amount of carbohydrate. Lupins contain other things beside carbohydrate. For example, lupins also contain lots of protein. We have successfully mimicked the effect of lupins feeding by giving animals pure carbohydrate as glucose or as propylene glycol. It is our theory that high levels of carbohydrate in the diet act very quickly probably within 3 or 4 days to produce more eggs. The purpose of this project is to test this theory and explain how it works. In order to test our theory we need to study how quickly the food an animal eats affects its egg production. In order to do this we will develop an in vivo model to test the normal speed of response of the ovarian control systems that regulate egg production. We will then examine how high carbohydrate diets modify the response time of these control systems and their effects on egg production. We expect that this research will increase our understanding of how diet affects fertility, which is of particular interest to farmers, veterinarians and medical practitioners.

动物吃什么对它的生育能力有很大影响。更具体地说，如果雌性绵羊在交配前得到良好的饮食，她们将比喂养糟糕饮食的同类母羊产生更多的双胞胎。这种现象最显著的特点是，良好的喂食期只需要持续3到4天。良好的营养对双胞胎数量的影响被归结为在交配前的几天里刺激产卵。为什么会发生这种情况还完全不清楚，这项研究将调查这种情况是如何发生的。我们团队和该领域其他研究人员发表的研究指出，饮食中能量含量的增加是产生这种效果的最重要的原因之一。在绵羊身上，这种额外能量的主要来源是植物碳水化合物，因此我们将注意力转向碳水化合物的作用，试图揭开这一现象背后的生物机制。我们对碳水化合物的兴趣主要是基于澳大利亚研究人员对所谓的“羽扇豆效应”发表的信息。简而言之，澳大利亚人发现，在交配前短短3天内给绵羊补充羽扇豆类谷物，将可靠而持续地刺激补充后的羊群中更多的双胞胎出生。那么，羽扇豆有什么特别之处呢？它们的碳水化合物含量很高。羽扇豆除含有碳水化合物外，还含有其他物质。例如，羽扇豆素也含有大量蛋白质。我们已经成功地模仿羽扇豆素的喂养效果，给动物喂食纯碳水化合物，如葡萄糖或丙二醇。我们的理论是，高水平的碳水化合物在饮食中起作用非常快，可能在3到4天内就会产生更多的鸡蛋。这个项目的目的是测试这一理论，并解释它是如何工作的。为了验证我们的理论，我们需要研究动物吃的食物对其产卵的影响有多快。为了做到这一点，我们将开发一个体内模型来测试调节卵子产生的卵巢控制系统的正常反应速度。然后，我们将研究高碳水化合物饮食如何改变这些控制系统的反应时间，以及它们对鸡蛋生产的影响。我们预计，这项研究将增加我们对饮食如何影响生育的理解，这是农民、兽医和医生特别感兴趣的。