Assimilation efficiency and gut passage time in an African elapid snake
We measured apparent assimilation efficiency (AAE) and gut passage time in the African elapid snake Hemachatus haemachatus under laboratory conditions. AAE was dependent on food type, being 89.8% when snakes were fed frogs and 82.8% when fed mice.
Differences in AAE for different meal types could be ascribed to the indigestible hair in mouse meals because differences were lost once this component of the mouse meals was removed from the calculation. AAE did not depend on snake body mass and there was no significant difference between AAE measures made at 20°C and 27°C for mouse meals. Gut passage time was 25% faster at 27°C than at 20°C, but was not affected by food type or snake body mass. Larger meals took longer to digest. Thus, H. haemachatus appears to offset reduced digestive performance at lower temperatures by retaining food in the gut for longer when at lower body temperatures (Tbs). These results fit an emerging pattern in snakes whereby digestive efficiency is generally high and insensitive to Tb over the selected thermal range, but may become dependent at lower Tbs when digestion is eventually arrested. The rate of digestion is highly temperature-sensitive and is fastest in the selected Tb range. Diet appears to affect digestive efficiency owing, mainly, to the presence of indigestible components such as hair. Using a comparative framework, venom does not appear to improve digestion for this species, at least over the temperature range tested, relative to other snake species in the literature.
Title: Assimilation efficiency and gut passage time in an African elapid snake, Hemachatus haemachatus.
Authors: Alexander GJ, Hanrahan SA and Mitchell D.
Source: African Journal of Herpetology (2012) volume 61, issue 1