Physiological basis for residual feed intake
Physiological basis for residual feed intake
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DOI：
10.2527/jas.2008-1345
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发表时间：
2009-04-01
影响因子：
3.3
通讯作者：
Arthur, P. F.
中科院分区：
文献类型：
--
作者：
Herd, R. M.;Arthur, P. F.
剩余采食量(RFI)是一种衡量饲料效率的指标，它与肉牛的体型和生长速度等生产水平无关，因此是研究饲料效率变化的生理机制的一个有用的新指标。五个主要的生理过程可能导致RFI的变化，这些过程与饲料摄入量、饲料消化、代谢(与身体成分变化相关的合成代谢和分解代谢)、体力活动和体温调节有关。关于安格斯方向盘的研究估计，代谢过程、身体成分和体力活动产生的热量解释了RFI变化的73%。这些过程解释的RFI的变化比例是：蛋白质周转率、组织新陈代谢和压力(37%)；消化率(10%)；热量增加和发酵(9%)；体力活动(9%)；身体成分(5%)；以及摄食模式(2%)。对牛的其他研究和对家禽的研究同样发现，这些过程对解释RFI很重要。到目前为止，已确定的生理机制是基于很少的研究，其中一些研究的样本量很小。这些生理过程中变异的基因组基础仍有待确定。早期的研究表明，数百个基因与RFI的差异有关，考虑到涉及的生理过程的多样性，这在事后可能并不令人惊讶。需要进一步的研究来更好地了解导致目标种群RFI变化的机制，并将生理信息与分子遗传学信息结合起来，这将成为对遗传优势动物进行商业测试的基础。
Residual feed intake (RFI) is a measure of feed efficiency that is independent of level of production, such as size and growth rate in beef cattle, and thus is a useful new trait for studying the physiological mechanisms underlying variation in feed efficiency. Five major physiological processes are likely to contribute to variation in RFI, these being processes associated with intake of feed, digestion of feed, metabolism (anabolism and catabolism associated with and including variation in body composition), physical activity, and thermoregulation. Studies on Angus steers following divergent selection for RFI estimated that heat production from metabolic processes, body composition, and physical activity explained 73% of the variation in RFI. The proportions of variation in RFI that these processes explain are protein turnover, tissue metabolism and stress (37%); digestibility (10%); heat increment and fermentation (9%); physical activity (9%); body composition (5%); and feeding patterns (2%). Other studies in cattle and studies in poultry similarly found these processes to be important in explaining RFI. The physiological mechanisms identified so far are based on very few studies, some of which have small sample sizes. The genomic basis to variation in these physiological processes remains to be determined. Early studies have shown many hundred genes to be associated with differences in RFI, perhaps in hindsight not surprising given the diversity of physiological processes involved. Further research is required to better understand the mechanisms responsible for the variation in RFI in target populations and to marry the physiological information with molecular genetics information that will become the basis for commercial tests for genetically superior animals.