In vitro response to EPA, DPA and DHA in cows and ewes.. PUFAmicro

The modulation of milk fat nutritional quality through fish oil supplementation seems to be largely explained by the action of n-3 very long chain polyunsaturated fatty acids (PUFA) on ruminal biohydrogenation (BH) of C18 fatty acids (FA) and rumen bacterial community. However, relationships among this action, disappearance of those PUFA in the rumen, and potential detrimental consequences on ruminal fermentation remain uncertain. This study compared the effect of 20:5n-3 (eicosapentaenoic acid; EPA), 22:5n-3 (docosapentaenoic acid; DPA), and 22:6n-3 (docosahexaenoic acid; DHA) on rumen fermentation and BH of C18 FA and was conducted simultaneously in cows and sheep to provide novel insights into interspecies differences. The trial was performed in vitro using batch cultures of rumen microorganisms with inocula collected from cannulated cows and ewes. The PUFA were added at a dose of 2% incubated dry matter, and treatment effects on ruminal C18 FA concentrations, PUFA disappearances, and fermentation parameters (gas production, ammonia and volatile FA concentrations, and dry matter and neutral detergent fiber disappearances) were examined after 24 h of incubation.

通过补充鱼油调控乳脂肪营养品质的效果，在很大程度上可归因于n-3超长链多不饱和脂肪酸（PUFA）对C18脂肪酸（FA）的瘤胃生物氢化（BH）以及瘤胃细菌群落的作用。然而，该作用、瘤胃内此类PUFA的消失量，以及瘤胃发酵潜在的不利影响之间的关联仍不明确。本研究比较了20:5n-3（二十碳五烯酸；EPA）、22:5n-3（二十二碳五烯酸；DPA）以及22:6n-3（二十二碳六烯酸；DHA）对瘤胃发酵和C18 FA生物氢化的影响，并同时在奶牛和绵羊中开展实验，以就物种间差异提供新的研究见解。本试验采用体外分批培养瘤胃微生物的方法，接种物取自带有瘘管的奶牛和母羊。将PUFA以占孵育干物质2%的剂量添加，孵育24小时后检测各处理对瘤胃C18 FA浓度、PUFA消失量以及发酵参数（产气量、氨浓度、挥发性脂肪酸浓度、干物质和中性洗涤纤维消失率）的影响。