Comparative Study on Bacterial and Fungal Loads from Siphoned and Unsiphoned Culture of African Catfish (Clarias gariepinus) Hatchlings

Abstract

This study was carried out to isolate, identify and determine the microbial loads that affect the culture of hatchlings (stage whereby hatchlings absorbed their yolk) in siphoned and unsiphoned water in fish culture. The hatchlings were separated into two groups of triplicate sampling bowls and labelled siphoned and unsiphoned. Samples were analysed for presence of bacteria and fungi using standard methods. The microbial analysis of the siphoned and unsiphoned culture of hatchlings was based on Total Viable Count (TVC) and Total Coliform Count (TCC). The bacterial examination was conducted to isolate and identify bacterial isolates. Serial dilution and inoculation were carried out using sterile media on crushed hatchling samples. Water sample was analysed by inoculating on Tryptone Soy Agar (TSA). For fungal identification both crushed hatchling and water were cultured on Sabouraud Dextrose Agar (SDA),  Isolates were examined macroscopically by colony shape, size, colour, and growing pattern, observed under microscope and identified with the help of fungal identification key. Bacterial identification was based on colonial, morphological and biochemical characteristics of colonies. The biochemical test were carried out on the bacterial isolates using catalase test, coagulase test, motility test, triple sugar iron test, indole test and motility test. One way anova was the statistical analysis used for all the results obtained in this experiment. The results showed that the bacterial isolates were Pseudomonas sp., Staphylococcus sp., Escherichia coli , Streptococcus sp., while the fungi include Penicillium sp., Aspergillus sp., and Mucor sp. The bacterial isolates showed trending pattern with an increase in count from the first day to the seventh day in unsiphoned as against the siphoned water sample. Conversely, the fungal isolates showed an inconsistent load value between siphoned and unsiphoned from the first day to the seventh. This study revealed that bacterial isolates are more associated than the fungal isolates in the hatchlings culture. The fungal load isolated are relatively lower and significantly different (P<0.05) than the bacterial load observed. Keywords: Bacterial, Fungal, African Catfish, Culturing methods, Hatchlings DOI : 10.7176/ALST/71-05