【作者】 李小磊；

【导师】 王中华；

【作者基本信息】 山东农业大学 ， 草业科学， 2014， 硕士

【摘要】 亚临床酸中毒是反刍动物其他代谢性疾病的重要诱因，危害很大，目前使用的主要的控制指标是日粮NDF水平，一般不低于20~28％，然而，已有研究表明NDF水平可能不是具有普遍指导意义的可靠指标，需要发展新的瘤胃酸碱平衡控制方法。瘤胃中的酸来自瘤胃微生物发酵和瘤胃上皮碳酸分泌，主要通过瘤胃壁吸收和内容物外排来清除，估计仅有30~40%的酸需要分泌唾液来中和，以往的研究主要集中于瘤胃发酵产酸和唾液分泌对瘤胃酸碱平衡的影响，对瘤胃上皮碳酸分泌在瘤胃酸碱平衡中的作用还缺乏有效的评估方法。为研究瘤胃液渗透压、pH值和VFAs浓度对碳酸分泌速率的影响，并提出预测方程，本试验利用四只做瘤胃小胃外科手术处理（从瘤胃上隔离一个小胃出来，保留其完整的血管和神经，排除了唾液中和和随内容物外排对酸碱平衡中的影响）的健康绵羊作平行处理，试验动物自由采食和饮水，试验期向瘤胃小胃里分别灌注同等体积不同渗透压、pH值和VFAs浓度处理的人工瘤胃液，灌注10min后全取人工瘤胃液，作为10min处理样，依次取20、30、40、50、60、70、80和90min处理样，一共是9个时间点，待测碳酸氢根浓度，得到时间与碳酸氢根量之间的曲线，拟合方程，求导，0时的数值/瘤胃小胃有效表面积即为当前条件下的碳酸分泌速率。试验结果表明瘤胃液渗透压、pH值和VFAs浓度都会影响瘤胃壁碳酸分泌速率，且随着瘤胃液渗透压的升高，瘤胃壁碳酸分泌速率降低，而随着瘤胃液pH值和VFAs浓度的增加，瘤胃壁碳酸分泌速率随之增加，最终我们分别得到了用渗透压(x)、pH值(y)、和VFAs浓度(z)来预测瘤胃壁碳酸分泌速率（umol/（h·cm2)）的回归方程，为：f(x)=183.33exp(-0.008x) R2=0.981;f(y)=exp(5.88-17.95/y) R2=0.909;f(z)=exp(4.32-126.74/z) R2=0.979更多还原

【Abstract】 Subacute ruminal acidosis is the important cause of ruminant other metabolicdiseases,the current control method is mainly NDF level of diet no less than20-28％,howeverother studies have shown that NDF level may have not general meaning to the reliableindicator.A new method of rumen acid-base balance control need to develop.Previous studiesreveled that ruminal protons came from volatile fatty acids produced by microbialfermentation and carbonic acid secretion by reticulo-rumen epithelium. These protons wereremoved mainly by epithelium absorption and outflow of contents. It was estimated that only30~40%of the protons was neutralized by secreted saliva. Research interests up to nowmainly concentrated on the influence of volatile fatty acid production and saliva secretion inbalancing reticulo-rumen acid-base. Effective method to evaluate the effects of carbonic acidsecretion on reticulo-rumen acid-base balance remains a research gap. To study the effects ofrumen osmotic pressure, pH and the VFAs concentration on carbonic acid secretion rate,and proposes the forecast equation,Four healthy sheep with litter rumen surgicaltreatment(isolate out a litter rumen from reticulo-rumen,keep complete blood vessels andnerves,eliminate the influence of saliva neutralizing and outflow of contents for acid-basebalance)made parallel processing,feed freely and drink freely during the test.Perfused thesame volume of artificial rumen fluid under the different pH, VFAs concentration, andosmotic pressure processing,produced all the perfusate after10minutes,then produced thesame perfusate of20、30、40、50、60、70、80and90minutes,a total of nine point intime,measuring the content of bicarbonate in the sample.We get the curve and equationbeween time and n(HCO3ˉ), derivation, the rate of carbonic acid secretionthe=value of0/effective surface area.The results showed that osmotic pressure,pH and VFAs concentrationeffect the rate of bicarbonate secretion,and the rate of bicarbonate secretion decrease alongwith the rise of osmotic pressure of rumen,and the rate rise along with the rise of pH of rumen fluid and VFAs concentration. researching the influencing factors of rumen epithelial carbonicacid secretion rate It is anticipated that equations predicating epithelial rates of carbonic acidsecretion(umol/（h·cm2)) based on theosmotic pressure (x), pH(y),andVFAsconcentration(z)of reticulo-rumen fluid can be acquired.Respectively,f(x)=183.33exp(-0.008x) R2=0.981;f(y)=exp(5.88-17.95/y) R2=0.909;f(z)=exp(4.32-126.74/z) R2=0.979更多还原