OSMOLALITY OF BLOOD AND INTESTINAL CONTENTS IN THE PIG, GUINEA PIG, AND ASCARIS LUMBRICOIDES

Abstract

It is confirmed that the small intestine of the pig has contents which are hypertonic to both pig serum (I) and the hemolymph (II) of the parasite Ascaris lumbricoides. With starved pigs (in the abattoir) the following osmolalities were recorded: intestinal contents, 427; I, 340; II, 323; and one sample of ascaris faeces (III), 311 milliosmolal (mOsm). Samples from normally fed pigs, obtained within 10 minutes post-mortem, gave a mean value of 311 mOsm for I and the contents of the anterior section of the small intestine averaged 320 mOsm, but those of the middle section averaged 391 mOsm. I, obtained from the ears of normal pigs, was only 302 mOsm. The contents of guinea pig small intestine decreased from 326 mOsm to 292 mOsm with 24 hours starvation, but no changes were detected in guinea pig I and the average value was 297 mOsm. The osmotic gradient across the body wall of A. lumbricoides is reversed soon after the worms are removed from the pig, and this effect is delayed at a lower temperature. The reversed osmoregulation is assisted by the ejection of III hypotonic to the hemolymph. It is confirmed that the chloride rise in II is slow, but it is shown that the potassium drop occurs soon after the worms leave their host. There was a significant but small decrease in chlorides of II when the worms were in media containing low chlorides.