Effects of neem leaves aqueous extract on organ histology, haematological parameters and biochemical indices in catfish

الملخص EN

Aqueous extract of neem leaves has been used on fish-farms to control of fish parasites and fish fry predators such as dragon-fly larvae.

Generally, Neem extract is considered of low toxicity towards non-target aquatic life.

Therefore, the effects of Neem leaves (Azadirachta indica) aqueous extract on catfish were investigated using the histology of intestine, gill and liver, haematological and biochemical parameters as indices.

Ninety (90) post-juvenile African catfish (Clarias gariepinus) weighing 42.40 ± 2.50g were used.

Experimental groups in triplicate were exposed bi-weekly to 3.5% and 7% LC50 of neem leaves aqueous extract infused in commercial floating feed for four weeks while the control group was exposed to untreated feed.

At the end of 4 weeks, blood samples were collected for biochemical and haematological analysis and organs (intestine, gills and liver) were collected.

The tissues from all the groups showed no visible pathological changes indicating non-toxicity to liver, intestine and gills of Clarias gariepinus.

All haematological values were within normal range and increase in the level of circulating lymphocytes in neem treated groups may be indicative of immune response readiness and hence suggestive of immune stimulation by neem extract.

Progressive decrease in AST and ALT levels indicates hepato-protective activity of Neem leaves meal while increase in total protein and globulin levels recorded indicated immune stimulatory effect of Neem.

Therefore, the use of Neem leaves aqueous extract in fish industry should be encouraged because of its efficiency in enhancing immunity against disease and suppression of the growth of specific pathogenic organism.