Selective non digestion of yellow mealworm Tenebrio molitor larvae by arowana

Gomez, Dennis Kaw; Kim, Ji Hyung; Choresca, Casiano Hermopia Jr.; Baeck, Gun Wook; Park, Se Chang

Korean Journal of Veterinary Research 2007;47(2):191-195.

Dennis Kaw Gomez¹, Ji Hyung Kim², Casiano Hermopia Jr. Choresca³, Gun Wook Baeck⁴, Se Chang Park²

¹KRF Zoonotic Disease Priority Research Institute, Seoul National University
²Brain Korea 21 Program for Veterinary Science, College of Veterinary Medicine, Seoul National University
³College of Veterinary Medicine, Seoul National University
⁴Faculty of Marine Technology, Chonnam National University

Abstract

This study reveals the unusual case reported for the first time on the selective non digestion of yellow mealworm (Tenebrio molitor) larvae by arowana fish. In January 2005, an Asian arowana (Scleropages formosus) (red variety), from Daesang Tropical Fish Corporation, Seoul, Korea, mortality was observed due to unknown cause. No putative causal factors were suggested by bacteriological and parasitological examinations. Internal examination of the dissected stomach showed some undigested debris with mandible parts of mealworms attached to the mucosal lining of stomach wall. Feeding experiment of yellow mealworm (Tenebrio molitor) was conducted on the silver arowana (Osteoglossum bicirrhosum). Result showed that on the test group, fish released vomitous material containing undigested mandibles of mealworm was observed on the 24th day of the feeding experiment. Histopathological examination of the cross section of the stomach wall layers of the test groups, showed detached parts of the mucosal layer and gastric pits around the damaged area with intact mucularis tissues. While the control group fed with mealworm larvae without head part showed intact stomach wall layers consisting of gastric pit, mucosa and mucularis tissues. Fish on both treatments survived until the termination of experiment. The removal of mealworm larvae head before feeding probably help or aid in the fast digestion of these insect larvae.

Key Words: non digestion, Osteoglossum bicirrhosum, Scleropages formosus, Tenebrio molitor