US-Brazil Cooperative Research: Gut Microclimate in Neotropical Armored Catfish (Loricariidae)

Towson University, Towson MD

Investigators

Abstract

This Americas Program award will support a US-Brazil research project between Dr. Jay A. Nelson, Towson University, and Dr. Francisco Tadeu Rantin, Federal University of Sao Paulo. The goal of the project is to investigate the digestive system and gut environment of the loricariid catfish. These researchers will use large loricariids to test the null hypothesis that the lumen of the loricariid gastrointestinal tract is anaerobic as in other vertebrates. They will investigate the environment of the gastrointestinal tract and the blood draining it in animals that are breathing either water only or both water and air. Unlike the guts of most animals, which are highly anaerobic, loricariid catfishes use their digestive tracts to uptake oxygen from air gulped in with water, so that the gut may be an aerobic environment. Our current understanding of the digestive physiology of herbivorous fishes is poor, and given the evidence that loricariids have a strange and unique digestive physiology, it is important that we broaden this knowledge. In this work Nelson will combine his knowledge of respiratory physiology with Rantin's capabilities for studying the physiology of large loricariids. The results of this study should aid in understanding the respiration and digestion of these fish, which constitute a highly diverse and ecologically important group of herbivorous fishes that has received little scientific attention.