The development of sensory organs in African catfish Qlarias gariepinus during larval to juvenile stage

Mazfarina Mustafa, (2008) The development of sensory organs in African catfish Qlarias gariepinus during larval to juvenile stage. Universiti Malaysia Sabah. (Unpublished)

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Abstract

This study was conducted to clarify the development of the sensory organs with larval growth in African cafish, Clarias gariepinus for the purpose of understanding its ecology as well as to improve the larval rearing techniques. Eggs were collected from Borneo Marine Researched Institute and the larvae of African catfish were reared from hatching to juvenile stage, sampled every day and observed under light microscope for the development of the sensory organs. Larvae were fed with rotifers, Artemia nauplii and artificial powder feed. The 20, 25 and 30-day-old larvae were 16.85±1.53mm, 19.17±1.48mm and 24.19±2.61mm (mean ± S.D) in total length (TL). During these days after hatching, the eye already deeply pigmented. The nucleicone ratio was increase with larval growth. The ratio exceeds 1.0 when the fish were 20-day-old. The cone-nuclei ratio was increase showed that the appearance of rods cell in the retina of the African catfish. The thickness of the outer nuclear layer in the retina also increases with larval growth showing an increase in rod density. As a result of the width added from the pigmented epithelium layer, visual cell layer and outer nuclei layer, the bottom area became thicker than other areas of the retina because the visual cell nuclei of the bottom area became longer than those in other areas. Related to its behaviour, African catfish larvae mostly stayed at the middle and bottom part of the tanks and they showed negative phototaxis. The appearance of rods cell indicates that the larvae of African catfish preferred to stay in dark environment. The development of olfactory organs increased with larval growth showed that African catfish response to chemical stimuli in the early larval stage. They showed strong chemotaxis behaviour when they were fed with artificial feed powder. The taste buds were found in barbels, mouth, buccal cavity and gill rankers showed that the African catfish larvae can improve their feeding behaviour because taste buds allow larvae to choose among food items. The African catfish larvae also showed the positive rheotaxis behaviour in this larval stage. The development of the sensory organs is accompanied by behavioural changes that have important implications for larval ecology at their natural habitat and African catfish larval rearing.

Item Type: Academic Exercise
Uncontrolled Keywords: sensory organs, larval growth, African cafish, ecology, larval rearing techniques
Subjects: S Agriculture > SF Animal culture
Divisions: SCHOOL > School of Science and Technology
Depositing User: Unnamed user with email storage.bpmlib@ums.edu.my
Date Deposited: 09 Jun 2016 02:16
Last Modified: 27 Oct 2017 09:07
URI: http://eprints.ums.edu.my/id/eprint/12367

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