The Applicability of Agar-Diffusion Test in Measuring Deoxyribonucleases in Pig Intestinal Content

The suitability of an agar-diffusion test (ADT) using toluidine blue deoxyribonucleic acid agar (TDA) for measuring DNase activity in pig intestinal contents was investigated. The ADT was compared with a spectrophotometrical method. Distinct metachromatic zones around wells in the DNA-containing agar, into which the intestinal content was applied, indicated DNase activity. The DNase activity was determined semiquantitatively by making serial twofold dilutions of the intestinal content. The spectrophotometrical method was optimal at pH 7.2. The ADT proved to be most sensitive at pH 5.6. The ability of the 2 methods employed to measure low concentrations of DNases was equal. However, the ADT was considered more suitable than the spectrophotometrical method because ADT measured reduced amounts of enzyme. DNase activity was demonstrated throughout the small intestine and in the large intestine. By the zymogram technique, at least 3 different DNases could be demonstrated in the lower parts of the small intestine, 1 of which could be of extrapancreatic origin.