生长育肥猪后肠纤维分解菌的数量及微生物发酵作用

本试验采用严格厌氧微生物学方法 ,对生长肥育猪的盲肠、结肠和直肠内容物中总厌氧菌和纤维分解菌的数量、纤维素酶活性、氨态氮和VFA含量进行了测定。结果表明 ,盲肠和直肠内容物中纤维分解菌的数量显著高于结肠(P<0.01) ;盲肠内容物中羧甲基纤维素酶活性最高 ,其次是结肠 ,直肠最低(P<0.05) ;直肠和盲肠的氨态氮浓度显著高于结肠(P<0.05) ;盲肠、结肠和直肠的总VFA含量分别为82.79、154.47和143.80mmol/L ;乙酸的摩尔百分比为盲肠>结肠>直肠 ;丙酸的摩尔百分比无明显改变 ;丁酸的摩尔百分比为盲肠<结肠<直肠(P>0.05)。本试验证明 ,饲喂玉米—豆粕型日粮的生长肥育猪后肠中存在相当数量的纤维分解菌 ,盲肠、结肠和直肠内容物中纤维分解菌的数量分别占可培养微生物区系的8.6 %、3.1 %和22.1 %。后肠微生物发酵类型为乙酸发酵型。

POPULATIONS AND ACTIVITY OF CELLULOLYTIC BACTERIA IN THE HINDGUT OF GROWING FINISHING PIGS

Three finishing pigs(average LW 95 kg)fed the conventional corn-soybean meal diet were used to determine the number of total anaerobic and cellulolytic bacteria,the activity of carboxymethyl cellulase(CMCase)and the concentration of NH3-N and volatile fatty acids for the digesta samples from cecum,colon and rectum.The population of cellulolytic bacteria from cecum and rectum was significantly higher(P<0.01) than that of colon.CMCase activity from the three segments were cecum>colon>rectum(P<0.05).The NH3-N concentration of rectum and cecum was significantly higher(P<0.05) than that of colon.The concentration of total volatile fatty acids in the three segments were 82.79,154.47 and 143.80mmol/L.Acetate molar percentage was cecum>colon>rectum;propionate molar percentage did not vary significantly;whereas,butyrate molar percentage was cecum0.05).The present results indicated that there were substantial populations of cellulolytic bacteria in the hindgut of finishing pigs fed the conventional corn-soybean meal diet,and the celluloytic bacteria accounted for 8.6%,3.1% and 22.1% of total cultural microflora,respectively.The fermentation pattern in the hindgut of finishing pigs was acetate fermentation type.