Computational analysis of the developing spiral intestine in Leucoraja erinacea

The relationship between gut length and body length in vertebrates is an indicator of a species' environment and dietary needs. The length of the digestive tract to body length ratio is much larger in herbivores than in carnivores. In humans, our digestive tract is roughly 7.5 meters long or 21.5 feet, this length is necessary for us to completely breakdown our nutrient-rich sources. As a consequence of human’s cooking food, our intestinal morphology has varied from our primate ancestors. Understanding the relationship of gut length to body length for animals is a significant piece of evolutionary development and dietary needs for species conservation. All cartilaginous fish, including the skate Leucoraja erinacea have a unique spiral intestine. The length of the intestine has to remain compact in order for these marine animals to maintain buoyancy, as the lobes of the liver extend to fill the abdominal cavity. The inner spiral shape of the intestine provides an effective rate of absorption required by their high protein diet, in a short length of intestine. A mathematical analysis of skate spiral intestine provides a more complete understanding of the relationship between surface area, volume, body length and total height. Providing insights into how the spiral intestine forms during development. To examine surface area to volume ratios of the spiral intestine, 3D models of spiral intestines from embryos at stages 27, 30 and 34 were generated from micro CT scans, and used to measure gut length. Here I report on gut length to body length growth, and SA/V ratios of the spiral intestine during development. Comparisons of these ratios with other organisms provides insights into variations seen between vertebrates of different gut morphologies.