Meeting Abstract

P1.87  Monday, Jan. 4  Effects of fasting and food habits on the intestinal performance of fishes HALL, David J.*; DAY, Ryan ; SECOR, Stephen M.; University of Alabama; University of Queensland; University of Alabama djhall1@crimson.ua.edu

We examined the impact of fasting on the intestinal performance of the omnivorous channel catfish (Ictalurus punctatus) and the carnivorous largemouth bass (Micropterus salmoides). We quantified for fasted and fed fish, intestinal uptake of L-leucine, L-proline, and D-glucose using the everted-sleeve technique, and activities of intestinal aminopeptidase-N (APN) and maltase using colorimetric assays. Neither species experienced a change in intestinal mass with fasting. Fasting catfish had significantly downregulated small and large intestinal uptake of the three nutrients, with uptake capacity declining by 58% after 1 week of fasting. Catfish also experienced with fasting a decline in intestinal APN activity (by 48%), but no change in maltase activity. In contrast, fasting largemouth bass did not experience a decrease in nutrient uptake for their intestinal ceca or small intestine, nor the downregulation of intestinal APN (with the exception of the ceca) or maltase activity. To explore potential relationships between feeding habits and intestinal function, we compared intestinal nutrient uptake and hydrolase activities of fasted catfish, bass, and the herbivorous grass carp (Ctenopharyngodon idella). Intestinal uptakes of L-leucine and D-glucose varied significantly among species, as both were transported at higher rates in grass carp intestines compared to either catfish or bass intestine. Similarly, activities of intestinal ANP and maltase varied among species with the activities of both hydrolases significantly greater for the grass carp compared to either the catfish or bass. Fish species vary in their capacity to regulate intestinal performance with feeding and fasting. For these three fish, intestinal breakdown and absorption of glucose increases with the amount of plant material in their diet.