Most traits in animal breeding, including feed efficiency traits in pigs, are affected by many genes with small effect and have a moderately high heritability between 0.1 and 0.5, which enables efficient selection. Since the microbiota composition in the gastrointestinal tract is also partly heritable and was shown to have a substantial effect on feed efficiency, the host genes affect the phenotype not only directly by altering metabolic pathways, but also indirectly by changing the microbiota composition. The effect m i of the microbiota composition on the breeding value g i of an animal i is the conditional expectation of its breeding value, given the vector φ i with microbiota frequencies, that is m i = E g i | φ i . The breeding value g i of an animal can therefore be decomposed into a heritable contribution m i that arises from an altered microbiota composition and a heritable contribution p i that arises from altered metabolic pathways within the animal, so g i = m i + p i . Instead of selecting for breeding value g ^ i , an index comprising the two components m ^ i and p ^ i with appropriate weights, that is I i = λ 1 m ^ i + λ 2 p ^ i , can be used. The present study shows how this breeding strategy can be applied in pig genomic selection breeding scheme for two feed efficiency traits and daily gain.

中文翻译：

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选择全基因组以提高猪的饲料效率——一种新的选择指数

动物育种中的大多数性状，包括猪的饲料效率性状，都受许多基因影响，影响较小，具有0.1-0.5之间的中等高度遗传力，可以进行高效选择。由于胃肠道中的微生物群组成也是部分可遗传的，并且显示出对饲料效率有重大影响，宿主基因不仅通过改变代谢途径直接影响表型，而且还通过改变微生物群组成间接影响表型。微生物群组成对动物 i 的繁殖价值 gi 的影响 mi 是其繁殖价值的条件期望，给定向量 φ i 和微生物群频率，即 mi = E gi | φ i 。因此，动物的育种值 gi 可以分解为由微生物群组成改变引起的可遗传贡献 mi 和由动物体内代谢途径改变引起的可遗传贡献 pi，因此 gi = mi + pi 。代替选择育种值 g ^ i ，可以使用包含具有适当权重的两个分量 m ^ i 和 p ^ i 的指数，即 I i = λ 1 m ^ i + λ 2 p ^ i 。本研究展示了这种育种策略如何应用于猪的基因组选择育种计划，以获得两种饲料效率性状和日增重。可以使用包含具有适当权重的两个分量 m ^ i 和 p ^ i 的指数，即 I i = λ 1 m ^ i + λ 2 p ^ i 。本研究展示了这种育种策略如何应用于猪的基因组选择育种计划，以获得两种饲料效率性状和日增重。可以使用包含具有适当权重的两个分量 m ^ i 和 p ^ i 的指数，即 I i = λ 1 m ^ i + λ 2 p ^ i 。本研究展示了这种育种策略如何应用于猪的基因组选择育种计划，以获得两种饲料效率性状和日增重。