International Journal of Agricultural Policy and Research
Vol.6 (7), pp. 98-110, July 2018
Available online at https://www.journalissues.org/IJAPR/
Author(s) retain the copyright of this article. Author(s) agree that this article remain permanently open access under the terms of the Creative Commons Attribution License 4.0 International License.
Original Research Article
Analysis of micro-algae grazing and filtering activity of Tilapia zillii in the Ziga reservoir in Burkina Faso (Western Africa)
*1Neya Bapiyan Augustin, 2Kabré Tinkoudgou Jean André and 2Zongo Bilassé
1The Environmental Monitoring Laboratory of the National Office for Water and Sanitation in Burkina Faso (ONEA).
2Peach and Wildlife Research and Training Laboratory of the Polytechnic University of Bobo Dioulasso (Burkina Faso).
*Corresponding Author Email: nbapiyan(at)gmail.com
From February 2014 to January 2015, 408 water samples were collected in eleven points installed throughout the Ziga dam and in six points of the raw water supply continuum. The analysis of these samples using a Primo Star light microscope equipped with a camera revealed 44 algal groups in the dam lake. In the meantime, 205 Tilapia zillii fish were harvested from 11 points installed throughout the dam. Collected fish individuals were eviscerated and the stomach and intestinal contents were stored at 5% formaldehyde in 50 ml pill containers for analysis in the laboratory. Analysis of the contents revealed different groups of algae in the diet of T. zillii and according to their numerical importance we have Chromophyta (76.50%), Chlorophyta (12.43%), Cyanophyta (4.67%), Pyrrophyta (1.20%) and Euglenophyta (0.94%). Helminth eggs (4.27%) were recorded with algal species. The intestinal coefficient of T. zillii was identified in the range of 5.1 to 7.4 confirming the position of this fish species in the trophic level as phytophagous fish species. The analysis of the stomach and intestinal contents of T. zillii also highlighted preferential preys such as species of Melosira, Cymbella and helminth eggs; secondary preys such as species of Cosmarium, Nostoc and Tribonema. All identified preys are biological pollutants of water quality and are harmful to human and animal health. From the correlation coefficients, the phytoplanktonophagous feeding habit of T. zillii has been established. The species does not change its phytoplankton diet, either according to its size or to the periods of abundance or shortage of preys. According to the characteristics of the prey species, the fish species may be considered as an important biological material to control the quality of polluted water collected into treatment plants to supply drinking water to populations. Using grazing and filtering fish species as T. zillii to clean raw water is in one hand, a biological contribution to water pollutants control, and in the other hand, an alternative against chemical treatments for drinking water; chemicals that can cause health hazard to human
Key words: Tilapia zillii, biological control agent, micro-algae, water quality, Ziga dam, Burkina Faso.