Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds

An on-station trial was conducted to investigate the effects of three C/N ratios (10/1, 15/1 and 20/1) along with substrate presence or absence on natural food communities in freshwater prawn culture ponds. An experiment was carried out in 40 m2 ponds stocked with a stocking density of 2 prawn juve...

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Main Authors:	Asaduzzaman, Md., Rahman, Mohammad Mustafizur, Azim, M. Ekram, Islam, Md. Ashraful, Wahab, Md. Abdul, Verdegem, Marc, Verreth, Johan
Format:	Article
Language:	English
Published:	Elsevier B.V. 2010
Subjects:	SH Aquaculture. Fisheries. Angling
Online Access:	http://irep.iium.edu.my/2623/ http://irep.iium.edu.my/2623/ http://irep.iium.edu.my/2623/ http://irep.iium.edu.my/2623/1/Effects_of_CN_ratio.pdf

id	iium-2623
recordtype	eprints
spelling	iium-26232011-10-24T04:19:24Z http://irep.iium.edu.my/2623/ Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds Asaduzzaman, Md. Rahman, Mohammad Mustafizur Azim, M. Ekram Islam, Md. Ashraful Wahab, Md. Abdul Verdegem, Marc Verreth, Johan SH Aquaculture. Fisheries. Angling An on-station trial was conducted to investigate the effects of three C/N ratios (10/1, 15/1 and 20/1) along with substrate presence or absence on natural food communities in freshwater prawn culture ponds. An experiment was carried out in 40 m2 ponds stocked with a stocking density of 2 prawn juveniles (5.023 ± 0.02 g)m−2. A locally formulated and prepared feed containing 30% crude protein with C/N ratio 10 was applied to all ponds. In order to raise the C/N ratio of the feed input to 15 and 20, tapioca starch was applied separately as a source of carbohydrate in addition to the artificial feed. Under substrate treatments, bamboo side shoots were posted vertically in pond bottoms resulting in 100% additional surface area as periphyton substrates. The treatments with different C/N ratios are referred to as “CN10”, “CN15” and “CN20”. Increasing the C/N ratio from 10 to 20 significantly increased the biovolume of phytoplankton, crustaceans and rotifers in the water column by 15%, 6% and 11%, respectively. The biovolume of periphyton was 50% higher in treatment CN20 compared to treatment CN10. Increasing the C/N ratio from 10 to 20 raised the biovolume of total heterotrophic bacteria(THB) in the water column (70%), sediment (36%) and periphyton (40%). The chironomids biovolume was also significantly higher (28%) in treatment CN20 compared to treatment CN10. The addition of substrates decreased the biovolume of water column plankton by 14% but the combined biovolume (plankton+periphyton) was almost double in substrate-added ponds. The biovolume of plankton, periphyton and THB increased significantly with culture time duration whereas the biovolume of benthic macroinvertebrates decreased significantly with culture time indicating that freshwater prawn grazed on them. A significant interaction between C/N ratios and substrate presence or absence was only observed for plankton biovolume in the water column. This study demonstrated that plankton, periphyton and microbial biofloc communities were under-utilized by the freshwater prawn in treatment CN20. This leaves room for increasing the stocking density of prawn and/or inclusion of periphyton grazing fish species to improve nutrient utilization efficiency and overall sustainability. Elsevier B.V. 2010-08-15 Article PeerReviewed application/pdf en http://irep.iium.edu.my/2623/1/Effects_of_CN_ratio.pdf Asaduzzaman, Md. and Rahman, Mohammad Mustafizur and Azim, M. Ekram and Islam, Md. Ashraful and Wahab, Md. Abdul and Verdegem, Marc and Verreth, Johan (2010) Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds. Aquaculture, 306 (1-4). pp. 127-136. ISSN 0044-8486 http://www.sciencedirect.com/science/article/pii/S0044848610003650 10.1016/j.aquaculture.2010.05.035
repository_type	Digital Repository
institution_category	Local University
institution	International Islamic University Malaysia
building	IIUM Repository
collection	Online Access
language	English
topic	SH Aquaculture. Fisheries. Angling
spellingShingle	SH Aquaculture. Fisheries. Angling Asaduzzaman, Md. Rahman, Mohammad Mustafizur Azim, M. Ekram Islam, Md. Ashraful Wahab, Md. Abdul Verdegem, Marc Verreth, Johan Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
description	An on-station trial was conducted to investigate the effects of three C/N ratios (10/1, 15/1 and 20/1) along with substrate presence or absence on natural food communities in freshwater prawn culture ponds. An experiment was carried out in 40 m2 ponds stocked with a stocking density of 2 prawn juveniles (5.023 ± 0.02 g)m−2. A locally formulated and prepared feed containing 30% crude protein with C/N ratio 10 was applied to all ponds. In order to raise the C/N ratio of the feed input to 15 and 20, tapioca starch was applied separately as a source of carbohydrate in addition to the artificial feed. Under substrate treatments, bamboo side shoots were posted vertically in pond bottoms resulting in 100% additional surface area as periphyton substrates. The treatments with different C/N ratios are referred to as “CN10”, “CN15” and “CN20”. Increasing the C/N ratio from 10 to 20 significantly increased the biovolume of phytoplankton, crustaceans and rotifers in the water column by 15%, 6% and 11%, respectively. The biovolume of periphyton was 50% higher in treatment CN20 compared to treatment CN10. Increasing the C/N ratio from 10 to 20 raised the biovolume of total heterotrophic bacteria(THB) in the water column (70%), sediment (36%) and periphyton (40%). The chironomids biovolume was also significantly higher (28%) in treatment CN20 compared to treatment CN10. The addition of substrates decreased the biovolume of water column plankton by 14% but the combined biovolume (plankton+periphyton) was almost double in substrate-added ponds. The biovolume of plankton, periphyton and THB increased significantly with culture time duration whereas the biovolume of benthic macroinvertebrates decreased significantly with culture time indicating that freshwater prawn grazed on them. A significant interaction between C/N ratios and substrate presence or absence was only observed for plankton biovolume in the water column. This study demonstrated that plankton, periphyton and microbial biofloc communities were under-utilized by the freshwater prawn in treatment CN20. This leaves room for increasing the stocking density of prawn and/or inclusion of periphyton grazing fish species to improve nutrient utilization efficiency and overall sustainability.
format	Article
author	Asaduzzaman, Md. Rahman, Mohammad Mustafizur Azim, M. Ekram Islam, Md. Ashraful Wahab, Md. Abdul Verdegem, Marc Verreth, Johan
author_facet	Asaduzzaman, Md. Rahman, Mohammad Mustafizur Azim, M. Ekram Islam, Md. Ashraful Wahab, Md. Abdul Verdegem, Marc Verreth, Johan
author_sort	Asaduzzaman, Md.
title	Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
title_short	Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
title_full	Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
title_fullStr	Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
title_full_unstemmed	Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
title_sort	effects of c/n ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds
publisher	Elsevier B.V.
publishDate	2010
url	http://irep.iium.edu.my/2623/ http://irep.iium.edu.my/2623/ http://irep.iium.edu.my/2623/ http://irep.iium.edu.my/2623/1/Effects_of_CN_ratio.pdf
first_indexed	2023-09-18T20:10:14Z
last_indexed	2023-09-18T20:10:14Z
_version_	1777407428233527296

Effects of C/N ratio and substrate addition on natural food communities in freshwater prawn monoculture ponds

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