Santos Xavier, Llorente Gustavo A
Parc Natural de Sant Llorenç del Munt i l'Obac, Oficina Tècnica de Parcs Naturals, Diputació de Barcelona, Barcelona, Spain.
Comp Biochem Physiol A Mol Integr Physiol. 2008 May;150(1):75-9. doi: 10.1016/j.cbpa.2008.03.005. Epub 2008 Mar 14.
Ectotherm vertebrates show physiological mechanisms that reduce metabolic costs during prolonged fasting. Once feeding, these animals adopt a wide variety of metabolic responses such as changes in gastrointestinal organ masses. Up-regulatory responses after feeding have been widely explored in infrequently feeding snakes like pythons, whereas few studies have been devoted to frequently feeding snakes. In this study, we have considered the gastrointestinal responses after feeding in a frequent feeder, the viperine snake Natrix maura, in the Ebro Delta rice fields. In this habitat, viperine snakes are exposed to long periods of food deprivation due to the lack of available prey as a consequence of the man-induced rice cycle. We weighed prey items and full gut masses, and measured length of combined esophagus and stomach, and intestine of viperine snakes belonging to a wide range of sizes. Snakes concentrate foraging activity when rice fields were flooded. In this period, gut masses increased. Likewise, intestines increased in length during the feeding period, which suggests that viperine snakes probably experience a postfeeding hypertrophy of their small intestines that contributes to their larger length. Once the intestine length was corrected for the snake size, it was shown that adults present longer intestines than immature snakes, reflecting an increase in the posterior part of the body linked to the gonads development. This study contributes to explore the physiological responses to feeding in frequently feeding snakes modelled by abrupt shifts of food availability.
变温脊椎动物展现出在长期禁食期间降低代谢成本的生理机制。一旦开始进食，这些动物会采取多种代谢反应，比如胃肠道器官质量的变化。进食后的上调反应在像蟒蛇这样不常进食的蛇类中已得到广泛研究，而针对频繁进食的蛇类的研究却很少。在本研究中，我们考察了在埃布罗三角洲稻田中频繁进食的食螺蛇（Natrix maura）进食后的胃肠道反应。在这个栖息地，由于人为的水稻种植周期导致可获取猎物缺乏，食螺蛇会面临长时间的食物匮乏。我们称量了猎物和饱腹后的体重，并测量了不同大小的食螺蛇的食管和胃的总长度以及肠道长度。当稻田被水淹时，蛇类会集中进行觅食活动。在此期间，肠道质量增加。同样，在进食期间肠道长度也会增加，这表明食螺蛇的小肠可能在进食后出现肥大，这导致其肠道变长。一旦根据蛇的大小对肠道长度进行校正，结果显示成年蛇的肠道比未成年蛇更长，这反映出与性腺发育相关的身体后部的增长。本研究有助于探索以食物可获取性的突然变化为模型的频繁进食蛇类对进食的生理反应。
