Investigation of nematode Eustrongylides larvae infections in mudfish Clarias gariepinus and C. anguillaris from Bida floodplain of Nigeria

This is the first report and record of the determination whether mudfish Clarias were infected with the larvae of the nematode Eustrongylides. Also, documented the assessment of the socio-economic perceptions of three groups of fisher folks on the economy of infected mudfish Clarias fishing activities. Fifty-six (67.5%) of 83 mudfish Clarias caught by artisanal fisher folks were examined for the presence of the larvae of the nematode Eustrongylides. All the 8 sampled fishing localities in Bida floodplain of Nigeria had a mean intensity and abundance of at least 3 and 1 worm per fish per site, respectively. Two hundred and one (96.2%) of 209 worms recovered were from the musculatures at different depths resulting in undulations on the skin surfaces as grub-like presentations. The three groups of fisher folks assessed encountered economic losses from nematode infected mudfish Clarias which attract much debates or rejections during marketing due to its aesthetically displeasing appearance, faster deterioration, higher fragility in smoked form coupled with poorer taste compared to the wholesome ones. Infected female mudfish Clarias had higher worm burden than the males, for each fishing locality

Saprolegnia infections of salmonid fish

This paper deals firstly with the identification and characteristics of fungal pathogens that colonize salmonids and then considers the relative importance of the condition of the host fish and the environmental factors which may influence the interaction between pathogen and host.

Pathology of mixed infections of saprolegniasis-myxosporidiosis in Indian major carp (Catla catla Ham.)

An outbreak of saprolegniasis in Catla catla in composite carp culture ponds were recorded during winter season. The typical cotton wool growths were observed on whole body surfaces of catla along with sporadic mortality. The fungal invasion was only restricted to skin and no fungal elements were visible in any internal organs after periodic acid schiff staining. On histology, periportal accumulation of mononuclear cells in liver, presence of myxosporidean cysts in antieror kidney, eosinophilic granular cells reaction in submucosa of stomach and intestine, dilated and engorged blood vessels of brain along with sloughing of epidermis and hyperplasia at gill lamellar base were pronounced changes. The possible role of release of Saprolegnia toxin in producing internal organs pathology has been discussed.

Advantages of liquid nitrogen freezing of Penaeus monodon over conventional plate freezing

Liquid nitrogen frozen products are biochemically and organoleptically superior to conventional plate frozen products but beneficial effect of liquid nitrogen freezing over conventional plate freezing can exist only up to 59 days at a commercial storage temperature of -18°C.

Effect of liquid nitrogen freezing and subsequent storage on survival of Staphylococcus aureus and Streptococcus pyogenes in treated prawn meat

Prawn meat treated with Streptococcus pyogenes B-49-2 culture and Staphylococcus aureus ATCC-12598 culture were frozen in conventional plate freezer at -40°C and by spray type liquid nitrogen freezer. The frozen products were stored at -18°C. Streptococcus pyogenes B-49-2 showed low sensitivity to cold injury during freezing and frozen storage. Staphylococcus aureus ATCC-12598 survived during the entire storage period of 240 days. Total bacterial count of untreated prawn meat was found to be always lesser in liquid nitrogen frozen products than that in plate frozen products.