Antibacterial efficacies of some plant extracts against Aeromonas and Pseudomonas diseases of farmed catfish (Heterobranchus longifilis)

<p>Aeromonas and Pseudomonas diseases are responsible for mortalities of some farmed catfish in Nigeria. The objective of the study is to investigate the efficacies of extracts of some plants against Aeromonas and Pseudomonas diseases of <em>Heterobranchus longifilis</em>. Ethanol extracts of <em>Phyllanthus amarus, Allium sativum, Artemisia annua,</em> <em>Citrus limon</em>, <em>Moringa oleifera</em>, <em>Allium cepa</em> and <em>Azadirachta indica</em><strong> </strong>were tested against <em>Aeromonas hydrophila</em> and <em>Pseudomonas flourescens</em> of <em>H. longifilis</em> by disc diffusion assay. Extracts of <em>P. amarus, A. sativum, A. annua </em>and <em>C. limon</em> were significantly (P&lt;0.05) more sensitive to <em>A. hydrophila</em> and <em>P. flourescens</em> than <em>M. oleifera</em>, <em>A. cepa</em> and <em>A. indica</em> which were effective against <em>P. flourescens</em>. Minimum inhibitory concentrations (MIC) of the extracts were 25mg/ml for <em>P. amarus</em> and <em>A. annua</em>; 25 and 100mg/ml for <em>C. lemon</em> and <em>A. cepa</em> respectively and 50mg/ml for <em>A. indica</em>.  Alkaloid was demonstrated in all plants except <em>A. annua </em>by qualitative methods. Moderate amount (++) of cardiac glycosides was demonstrated in <em>A. sativum</em>, <em>M. oleifera</em> and <em>P. amarus</em>. Saponin (+++) was present in <em>M. oleifera</em> and <em>A. indica</em> while, tannin (++) was present in <em>M. oleifera</em>, <em>P. amarus</em> and <em>A. indica</em> respectively. Phlobatanins and Anthraquinones (++) were present in <em>P. amarus</em> and <em>M. oleifera</em> respectively.  Extracts of aforementioned plants have potentials as therapy against <em>Aeromonas hydrophila</em> and <em>Pseudomonas flourescens</em> of farmed catfish.</p>