酵母培养物对夏季生长育肥猪肠道菌群结构和发酵能力的影响

Effects of yeast culture on gut microbial composition and activity of growing-finishing pigs in summer

180头体质量(29.56±1.12)kg的杜×长×大三元杂交商品猪随机分为3组(每组6栏,每栏10头),对照组(C)饲喂玉米-豆粕型基础日粮,试验1组(T1)和2组(T2)日粮分别添加1.0和4.0 g.kg-1(以干物质计)的酵母培养物(YC),于生长期和育肥期末每栏随机抽取1头猪屠宰,采集回、结肠食糜样品,以研究日粮添加YC对肠道菌群结构和发酵能力的影响。同时以回肠食糜为底物、结肠食糜为接种物,研究体外模拟回肠食糜进入结肠后经微生物发酵产生挥发性脂肪酸(VFA)的浓度。结果表明:回、结肠食糜DGGE图谱显示YC组猪的菌群相似性更高;YC对回肠总菌数无显著影响,但显著减少生长期T2组及育肥期T1和T2组回肠乳酸杆菌数(P<0.05),生长期结肠乳酸杆菌数则有降低的趋势(P=0.06);YC有提高结肠丁酸产生菌数量的趋势(P=0.07);生长期T1组(P<0.05)和T2组(P<0.01)、育肥期T1组(P<0.05)回肠食糜乳酸浓度均显著低于对照组。体外模拟试验结果显示:YC显著提高了生长期肠道微生物产生丁酸的能力(P<0.01),但对生长期总VFA(TVFA)、乙酸、丙酸及育肥期TVFA和各酸浓度无显著影响。结论:夏季生长育肥猪日粮中添加YC能显著降低回肠乳酸杆菌数和乳酸浓度,提高结肠丁酸产生菌数和丁酸浓度,为肠道上皮细胞提供更多的能量。

180 pigs(Duroc × Landrace ×Yorkshire,(29.56±1.12)kg)were randomly allotted to three treatment groups(6 pens per treatment and 10 pigs per pen).The control(C)pigs were fed a basal corn-soybean meal diet.Treatment 1(T1)and 2(T2)were fed the same basal diet supplemented with 1.0 and 4.0 g·kg-1 of yeast culture(YC),respectively.At the end of growing and finishing phase,one pig per pen was randomly selected and slaughtered for ileal and colonic chime collection.DGGE and real-time PCR were used for characterization of intestinal microbiota.Ileal chymes as substrates and colonic chymes as inocula were to in vitro simulate intestinal microbial fermentation.The concentration of volatile fatty acid(VFA)and lactate in ileal and colonic chymes,and in end products of in vitro fermentation was determined to describe the activity of intestinal microbita.DGGE profiles from ileal or colonic chymes of the two YC groups revealed much more similarity than those from the control group.YC had no significant effect on the number of total bacteria in ileal or colonic chymes of growing-finishing(G-F)pigs.The number of Lactobacilli in ileal chymes of YC groups was significantly lower(P<0.05)than that of control group.The number of butyrate-producing bacteria in colonic chymes tended to increase(P=0.07)in YC groups.The lactate levels of ileal chyme in T1(P<0.05)and T2(P<0.01)group for growing pigs and in T1(P<0.05)group for finishing pigs were significantly lower than those in the control group.Results of in vitro fermentation showed that YC significantly elevated(P<0.01)butyrate production for growing pigs.In conclusion,YC supplemented into the ration of G-F pigs during summer significantly decreased the lactate level and number of Lactobacilli in ileal chymes,and increased the level of butyrate with a parallel increase of butyrate-producing bacteria number in colonic chymes.It will be helpful to maintaining physiologic function of intestinal cell by providing adequate energy.