Meeting Abstract
16.4 Sunday, Jan. 4 The sea urchin gut: size and nutrient storage are affected by temperature GIBBS, V.K.*; HOFER, S.C.; LAWRENCE, A.L.; LAWRENCE, J.M.; WATTS, S.A.; Univ. of Alabama at Birmingham; Univ. of Alabama at Birmingham; Texas A&M System; Univ. of South Florida; Univ. of Alabama at Birmingham vkgibbs@uab.edu
While numerous studies have investigated the various roles of the sea urchin gonad (nutrient storage and gamete production), very few have considered the role(s) of the gut. An annual cycle for gut size has been reported for Lytechinus variegatus from the Northern Gulf of Mexico, where size was inversely related to field temperature. In this study, adult L. variegatus (ca. 40 mm diameter) were exposed to one of three temperatures indicative of average field temperatures of winter, spring/fall, or summer (16, 22, or 28C, respectively). Individuals (n= 24 per treatment) were maintained in recirculating aquaria and fed a formulated diet ad libitum for 8 weeks. Gut (stomach and intestine) dry weight was inversely related to temperature (0.35 +/- 0.01, 0.26 +/- 0.01, and 0.17 +/- 0.01 g/individual for 16, 22, and 28°C, P<0.05). Concentration of carbohydrates (71 +/- 4, 57 +/- 4, and 53 +/- 4mg/g) and lipids (344 +/- 12, 250 +/- 15, 189 +/- 7 mg/g for 16, 22, and 28°C, respectively) were highest for individuals held at 16°C. Protein concentration, however, was directly related to temperature and was highest at 28°C (295 +/- 7, 345 +/- 7, 373 +/- 5mg/g, for 16, 22, and 28°C, respectively). These data suggest temperature will modify the size and function of the gut. At low temperatures, storage of nutrients (primarily lipid and to a lesser extent, carbohydrate) occur concomitantly with digestion. However, the nutrient storage function of the gut is greatly reduced when individuals are held at warmer temperatures despite ingesting similar amounts of feed as compared to individuals held at low temperature. This study was supported in part by the Mississippi-Alabama Sea Grant Consortium and Texas Sea Grant.
