摘要This study explored the effect of supplementing the diet with n-3 polyunsaturated fatty acids(PUFA)on liver gene expression and its contribution to the recovery of cows during the transition phase.A total of 30 multiparous non-lactating Holstein dairy cows(35 d before expected calving)were randomly fed a diet with either 1％dry matter(DM)of hydrogenated fatty acid(FA)(C16:00 enriched;control group[CON])or 3.5％DM of extruding flaxseed(n-3 enriched;HN3 group).The cows underwent a 7-d adaptation period,followed by a 28-d prepartum period and a 28-d postpartum period.In the beginning of the experiment,parity,body weight(BW),body condition score(BCS)and milk yield were 2.6±1.2,757.5±65.8 kg,3.3±0.2 and 10,286.5±1464.8 kg/previous lactation(mean±SD),respectively.The relative abundances of Bacteroidota(P=0.047)and Spirochaetota(P=0.091)were higher and that of Patescibacteria(P=0.076)was lower in the HN3 group than in the CON group on 4 d before prepartum.The dry matter intake(DMI)of cows was positively correlated with the abundance of bacteria in the rumen(Spirochaetota:r=0.871,P＜0.001;Bacteroidota:r=0.896,P＜0.001)and the differential expression of genes involved in taste transduction(ACSL1:r=0.673,P＜0.001;PLIN4:r=0.632,P＜0.01;CPT1A:r=0.694,P＜0.001).These results suggest that dietary n-3 PUFA at an appropriate concentration can promote DMI recovery by upregulating the expression of these genes and maintaining the balance of the rumen microbiota.