Absorption of Nucleic Acid from the Small Intestines of Swamp Buffaloes and Zebu Cattle

Three male yearling swamp buffaloes and three Kedah Kelantan (KK) zebu cattle of similar age and sex were used. Animals were each fed 4 kg of a total mixed ration diet (TMR) consisting of 40% oil palm frond and 60% concentrate for 2 wk. Cr2O3 was used as the indigestibility marker. On day 15, animals were sacrificed and the digesta in the small intestine was collected to study the absorption of purines in the segments, each being 60 cm in length of the small intestine. Deoxyribonucleic acid (DNA) disappearance from the first to the 15th segment did not differ between buffaloes and cattle (P > 0.05), averaging 94% and 91%, respectively. Ribonucleic acid (RNA) disappearance for buffaloes was lower than that for cattle (P < 0.05) (82% and 95%, respectively) but did not differ between species (P > 0.05). Similarly, purine absorption did not differ between buffaloes and cattle (P > 0.05). Total purine absorbed within 20 segments was 81% and 92% respectively for buffaloes and cattle. Although disappearance of RNA, DNA and the purine bases (PB) in the small intestine did not differ between cattle and swamp buffaloes (P > 0.05), based on concentration per Cr marker, the quantity of unabsorbed PB in the last 5 segments of the small intestine of buffaloes was higher than that of cattle (P < 0.05). Although this suggests that absorption of PB in the small intestine of buffaloes was lower than of cattle, it can not explain the large differences in the PD urinary excretion rates between the species.