Résumé:
Marine algae constitute an important reservoir of numerous natural molecules with diverse biological activities. The aim of this study is to evaluate the antibacterial activity of the hydroalcoholic extract of three sea algae, Cystoseira stricta, Cystoseira compressa and Cystoseira crinita, collected on the Mostaganémoise coast, exactly on the beaches of Clovis (commune of Ben Abdel Malek Ramadan) and Salamandre (commune of Mostaganem). Antibacterial activity is evaluated by the Muller Hinton agar diffusion method against several pathogenic bacteria: Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, Escherichia coli S55, Klebsiella pneumoniae and Salmonella Sp.Antibacterial activity results revealed an inhibitory effect of Cystoseira crinita and Cystoseira compressa against S. aureus ATCC 25923 (25 and 24mm), E. coli S55 (16 and 15mm), E. coli ATCC 25922 (13 and 14mm), Salmonella Sp. (15mm) and Klebsiella pneumoniae (14mm), respectively.However, no inhibitory effect was observed with Cystoseira Stricta extract on any of the bacterial strains tested. These results suggest that extracts of the algae Cystoseira crinita and Cystoseira compressa added to feed could have a beneficial impact on broiler growth. These extracts would be particularly effective against pathogenic staphylococci, which are relevant to avian health, as these bacteria are often associated with infections in poultry.
