日粮粗纤维水平对断乳力克斯兔腹泻率、消化道pH和盲肠菌群的影响

Effect of Crude Fiber Level on Diarrhea,Intestinal pH and Caecal Microbe of Rex Rabbit

为了探讨日粮中粗纤维水平对断乳仔兔腹泻率的影响及其低纤维型腹泻的发生机制,选择30～35日龄健康力克斯兔40只,随机分成4组,每组10只。在其他营养相近的基础上,分别饲喂粗纤维含量为7%、9%、12%和14%的日粮。观察不同纤维日粮对试兔腹泻率、肠道pH、盲肠挥发性脂肪酸(VFA)和微生物菌群的影响。研究表明:粗纤维含量对腹泻率有重大影响,中高纤维日粮(12%和14%)没有发生腹泻,而低纤维日粮组(7%和9%)的腹泻率分别为59.33%和20.67%,组间差异极显著(p<0.01);低纤维水平日粮组(7%、9%)的试验兔,胃、空肠、结肠、盲肠的pH值均高于中高纤维组(12%、14%),差异达显著或极显著水平(P<0.05或P<0.01);盲肠总挥发性脂肪酸随粗纤维含量的增加而上升,但差异不显著(P>0.05)。乙酸随粗纤维含量的增加而上升,CF14%组极显著的高于7%组(P<0.01)。丙酸和丁酸的变化不显著(P>0.05);纤维含量对盲肠主要微生物菌群有较大影响。从整体来说,有益菌(双歧杆菌、乳酸杆菌、拟杆菌和消化球菌)以CF12%组占优,CF14%次之,CF7%组最低。其中双歧杆菌各组间差异均达极显著水平(p<0.01)。而大肠杆菌与之相反,CF7%组检测出沙门氏菌。其他各组没有发现沙门氏菌,也未检出魏氏梭菌。该研究揭示了低纤维日粮使家兔消化道内环境(如pH、VFA等)发生变化,从而导致肠道菌群失调,是发生腹泻的主要机制。

To study the effect of crude fiber level on diarrhea percentage of weaned Rex rabiit and the mechanism of low fiber type diarrhea. 40 30-35-days old healthy Rex rabbits were randomly divided into 4 groups with 10 each. The diets which the crude fiber level was 7%, 9%, 12% and 14% were fed respectively. The diarrhea percentage, intestinal PH and cecal total VFA and microbe were calculated. Results showed that the CF content can significantly effected on diarrhea .The diarrhea percentage of 12%, 14%, 7% and 9% CF con- tent group were 0, 0, 59.33% and 20.67% （p〈0.01）respectively;The intestinal pH of 7%, 9% CF group was higher than that of 12%, 14% CF group （P〈0.05 or P〈0.01）; The cecal total VFA amount were raised with CF content ascended （P〉0.05）.The acetic acid amount of 14% CF group was greater than that of 7% CF group while the amount of pyruvic and butyric were similer. （P〉0.05）; The CF content can also effect on cecal total microbe significantly. The Bifidobacterium, Lactobacillus, Bacterrodes and Peptococcus in cecum of 12% CF group was densest and 14% and 7% CF group＇s Were followed. The Bifidobacterium amount were significantly different among the three groups （p〈0.01）. Salmonella was only found in 7% CF group. The conclusion is that the optimal crude level in weaned Rex rabbit diet is 12% and the mechasim of diarrhea is that low fiber level diet resulting in microecological maladjustment.