Antibacterial Property and Potential use Mulberry leaves (Morus alba Linn.) as Dietary Supplement on Growth Performance and Disease Resistance against Aeromonas hydrophila in Nile Tilapia (Oreochromis niloticus)

Abstract

The study on antibacterial activity of mulberry (Morus alba Linn.) extract against Aeromonas hydrophila and study on effect of supplementing diet with mulberry leaves on growth performance and resistance against A. hydrophila in Nile tilapia (Oreochromis niloticus) were conduct. Mulberry leaves were extracted by ethanol 95%. The result of antibacterial screening performed by disc method was 10.77+0.25 mm with inhibition zone. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentrations (MBC) of mulberry extract were also determined by broth dilution method. The results showed that MIC was 2785 ppm and MBC was not observed in any concentration of mulberry extracts. Moreover, the experimental fish with an initial mean weight of 2.34±0.82 g and length of 5.56±0.23 cm were stocked in 12 glasses aquariums. Each aquarium has dimension 45×90×45 cm and was filled with 150 liters of water at a stocking density of 20 fish/aquarium. The mulberry leaves was mixed in commercial feed (30% crude protein) with 4 different doses (0, 5, 10 and 15%w:w, respectively) and fed to Nile tilapia at satiation twice daily for 8 weeks. The results showed that fish fed experimental diets had no significant difference (P>0.05) in specific growth rate, feed conversion ratio, feed efficiency, survival rate, protein efficiency ratio and hepatosomatic index compared with control. Additionally, the mortality of fish challenged by A. hydrophila has been recorded for 10 days after challenging. The result showed that fish fed diet containing 15% mulberry leaves had significantly lowest mortality (P<0.05) and had highest relative percentage survival (RPS).