Title : Effect of acute toxicity of formalin on orechromis niloticus
Abstract:
The objective of this study is to investigate the effect of toxicity of formalin on oreochromis niloticus in Wudil Kano State, Nigeria. An experimental design was adopted for this study which involves two sets of experiment; determine acute toxicity of formalin and therapeutic effect of formalin. Method for acute toxicity test as recommended by Yadav and Singh (2009) were also employed. The research was conducted at the fish laboratory of the Biological Science Department, Nigeria Police Academy, Wudil Kano. The Nigeria police academy is located in Wudil, Kano state Nigeria. A total number of 36 tilapia juveniles (Oreochromis niloticus) were collected alive from River Wudil. Formalin was obtained as 40% formaldehyde. The following concentration were administered to each of them 0.5, 0.1, and 1.5mg/l. and control with 0.00mg/l. Each concentration had 4 treatments. 3 juveniles of the specimen were randomly selected and stock in each of the 12-plastic bowls and set the experiment randomly. A static bioassay was then use to determine the toxicity test of formalin for Oreochromis niloticus juveniles. Another set of fish infested with Cichlidogyrus spp. in aquaculture habitual conditions were exposed to different concentration of formalin, then observation was done to find the concentration range that effectively treats the disease or parasite while minimizing the harm to the fish. Change in appearance and mortality were also recorded. All data obtained were subjected to one-way Analysis of Variance (ANOVA) using Statistical Package for Social Sciences (SPSS), Version 23 for Windows. Differences in means were separated using Duncan’s new multiple range test (DMRT). Level of significance was determined at P=0.05 level of probability. The significant difference was established at 5% probability level (P<0.05) while the results generated were expressed as mean ± standard deviation (SD). The results showed that: at the concentration of 0.5mgl/l the means values of the fish mortality were 0.00, 0.00, 0.00, 0.33, 0.33 and 0.67 While at concentration 1.0 mean values of fish mortality were 0.00, 0.33, 0.33, 0.00, 0.67 and 0.33 and at concentration of 1.5mg/l mean values are 0.00, 0.67, 0.33, 1.00, 1.00 and 1.33. At 0.00 concentration there were no fish mortality at all. This showed that formalin has a therapeutic effect on fish infested with Cichlidogyn spp. It was therefore concluded that the use of formalin in lesser concentration based on this study does not have effect or is not toxic to Tilipia (Oreochromis niloticus). Also, if the period of the exposure of the fish does not exceed 6 hours, it is not going to be toxic to Oreochromis niloticus. More so, there is effectiveness in the use of formalin to reduce the infestation of fish by parasites. The study that recommended that indiscriminate use of formalin in water impoundments should be avoided or especially when the concentration is high to preserve fish diversity among others.
Keywords: Acute Toxicity, Formalin, Oreochromis Niloticus, Juvenile, Aquaculture.
