| Plant oil in the diet is known to alter milk fatty acid composition owing to changes in the supply of fatty acid precursors and/or activity of lipogenic enzymes both in the mammary gland and in somatic cells in lactating goats. Twelve Sannen goats were used in a3×3Latin square design with28-d experimental periods. Treatments were comprised of basic diets containing no additional oil (CON), linseed oil (LO;4%of diet DM), or LO with malate (LOM;2%of diet DM). Relative to the CON, LO and LOM enhanced milk fat yield (P-0.047) and milk fat content (P<0.015). The LO and LOM diets increased the concentration of plasma glucose (P<0.03) and TC (P<0.026) in plasma compared to the CON. The highest concentration of glucose was found with the LOM treatment. Feeding the LO and LOM diets increased, the concentration of C18:0(P<0.019, P<0.047), trans-1118:1(P<0.015, P<0.039), cis-9, trans-11-CLA (P<0.001, P<0.002) and C18:3n-3(P<0.001, P<0.038) in rumen fluid from1h to6h post-feeding compared to the CON diet. The LO and LOM diets increased the proportions of the C18:1n-9(P<0.013), VA (P<0.001), cis-9, trans-11-CLA (P<0.035), trans-10, cis-12-CLA (P<0.022) and C18:3n-3(P<0.001) in the plasma lipids. Relative increases in milk fat VA secretion were greater for LOM (+366%) than for LO (+313%), and cis-9, trans-11-CLA secretion were greater for LOM (+304%) and LO (+237%) compared to CON. The dietary LO and LMO decreased milk secretion of C4:0, C8:0, C10:0, C12:0, C14:0(P<0.012) and C16:0(P<0.016). The sum of the unsaturated fatty acid in the milk fat was also increased (P<0.021) by supplemental LO and LOM, resulting in an increased ratio of unsaturated fatty acids to saturated fatty acids (P<0.013) compared to that of the CON. The mRNA expression of LPL and SCD was increased in somatic cells and in the mammary gland by LO and LOM diets compared to the CON diet, and a greater SCD mRNA expression for the LOM diet groups was observed compared to the LO diet. Feeding a diet supplemented with LO to lactating goats is a efficacious way to significantly alter both the milk fat and fatty acid profile of the milk. A substantially increased CLA proportion in milk induced by the supplementation of LO with malate and associated with a higher SCD gene expression suggests that the LOM supplement may have a coordinated effect on gene expression in the mammary gland. Further, this study indicates that milk somatic cells are a valuable tool for evaluating the information regarding gene expression of enzymes involved in lipid metabolism.The rumen microbial ecosystem is a complex system, with the rumen fermentation processes involving interactions among microorganisms. Important relationships exist between diet and ruminal bacterial composition. We investigated ruminal bacterial community by using tag amplicon pyrosequencing analysis in Sanne goats fed linseed oil andmalate. The most abundant bacterial operational taxonomic units in the rumen were those related to feed differences. Previous studies examining the rumen microbiota have indicated the presence of core microbiota composed of Firmicutes and Bacteroidetes phyla. Here, further analysis indicated that Bacteroidetes was the most abundant member of the ruminal bacterial community and that the genus Prevotella was highly represented in our shared microbial community when steers were fed linseed oil and malate. However, for control and linseed oil diets, Firmicutes was the most abundant phylum and the family Ruminococcaceae was predominant. In summary, feeding ruminants a diet supplemented with a moderate level of linseed oil and propionate precursors may alter the ruminal fermentation pattern. The most positively responding to linseed oil and malate supplementation were Bacteriodetes and Firmicutes phyla, and Ruminococcaceae and Butirivibrio bacteria. This indicated that feed may significantly influence the composition of the rumen microbe community. |
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