Bacterial infection of mudfish Clarias gariepinus (Siluriformes: Clariidae) fingerlings in tropical nursery ponds

Abstract

Bacterial infection among the most common cultured mudfish Clarias gariepinus in Africa, has become a cause of concern, because it constitutes the largest economic loss in fish farms. In order to provide useful biological data of the pathogens for good management practices, samples were collected monthly between January 2008 and December 2009 in three monoculture nursery ponds, located in three different positions: upriver (A, grassland), mid-river (B, mixed forest and grassland) and downriver (C, rainforest) along 200km length of Cross River floodplains, Nigeria. A total of 720 fingerlings between 15.1 and 20.7g were analyzed to determine the degree of infection. The bacterial pathogens were taken from their external surfaces, and were isolated and identified by standard methods. The caudal fins of fingerlings from pond A had the highest bacterial load (5.8x10 3 cfu/g), while the least counts (1.2x103cfu/g) were identified on the head of fish from pond C, with Flexibacter columnaris as the major etiological agent. Pseudomonas fluorescens, Aeromonas hydrophila, Escherichia coli, Staphylococcus aureus and Micrococcus luteus were identified as co-isolates with P. fluorescens as dominant (0.7x10 2 cfu/mL) co-isolates in pond water. Clinical signs of five white spots with red periphery appeared on the external surface of infected fish. All the fish sampled, died after 4 to 9 days. There was no significant difference in the bacterial counts between different ponds, but the difference between fish organs/parts examined was significant. Fish from these ponds are therefore potentially dangerous to consumers and highly devalued, with the economic impact to producers. Preventive methods to avoid these infections are recommended.

Assessment and incidence of fish associated bacterial pathogens at hatcheries of Azad Kashmir, Pakistan

“…Microorganisms are a significant portion of the aquatic ecosystem. The interaction between these pathogens and the aquatic environment blowout the contagious diseases in the process of aquaculture (Boon and Huisman, 1996;Noga, 2000;Ikpi and Offem, 2011). Fish are susceptible to bacterial infections when cultivated in high-density conditions.…”

Dietary supplementation with low molecular weight sodium alginate improves growth, haematology, immune reactions and resistance againstAeromonas hydrophilainClarias gariepinus

“…In the last few years, demand has increased for low cost animal protein sources to close the gap between production and the growing population. Thus, most countries have turned to cultured Clarias species for their high reproductive capacity under natural and controlled conditions, high growth rate, tolerance of bad water conditions and high nutritional value (Ikpi & Offem, ; Khan & Abidi, ; Maneechot et al, ). Several trials using herbal and alternative medicine in fish culture (Hoseinifar et al, ) have been performed to overcome the side effects of using antibiotics for controlling different diseases that cause severe issues in humans, especially drug resistance and antibiotic residues (Chafer‐Pericas et al, ; Obaidat, Salman, & Lafi, ; Park, Jung, & Lee, ).…”

“…Clarias species for their high reproductive capacity under natural and controlled conditions, high growth rate, tolerance of bad water conditions and high nutritional value (Ikpi & Offem, 2011;Khan & Abidi, 2011;Maneechot et al, 2016). Several trials using herbal and alternative medicine in fish culture (Hoseinifar et al, 2015) have been performed to overcome the side effects of using antibiotics for controlling different diseases that cause severe issues in humans, especially drug resistance and antibiotic residues (Valente et al, 2006).…”

“…C. gariepinus are exposed to a wide variety of fungi, bacteria and parasites (Ikpi & Offem, ). Aeromonas hydrophila is a rod‐shaped Gram‐negative bacterium that is a major, widespread fish pathogen.…”

Pharmacokinetics of streptomycin sulfate in Staphylococcus aureus-infected Clarias gariepinus (Burchell 1822)

“…Fish like other animals are susceptible to bacterial infections. Ikpi and Offem (2010) reported that bacterial infection among cultured mudfish Clarias gariepinus in Africa, has become a cause of concern, because it constitutes the largest economic loss in fish farms. Similarly at Mississippi state University it was reported that of the overall catfish losses in the United States caused by infectious diseases, approximately 60 percent were the result of single or mixed bacterial infections, 30 percent resulted from parasitic infestations, 9 percent from fungal infections, and 1 percent of viral aetiology (MSU, 2010).…”