Psidium Guajava Leaf Extracts Fed to Mono-sex Nile Tilapia Oreochromis Niloticus Enhance Immune Response Against Pseudomonas fluorescens

Plants are being explored as a major source of medicinal compounds. The present study was intended to explore the efficacy of dietary doses of Psidium guajava leaf extracts mixed with Maize bran (control) on growth performance, immunological parameters and disease resistance against Pseudomonas fluorescens infection in mono-sex Nile tilapia, Oreochromis niloticus. Fishes (average weight 16.5±1.5) were fed five different doses of herbal diets for four weeks which prepared with 0%, 2%, 4%, 6% and 8% of P. guajava leaf extracts where maize bran used as control (0%). Growth performance and immunological parameters including bacterial activity and phagocyt activity were investigated. Among those doses 8% showed highest significant responses in phagocytic activity, specific growth rate, specific and non-specific immune responses on week 2 and 4 compared to control diet whereas the changes did not manifest on first week. Further the P. guajava leaf extracts enriched diet at 8% level resulted in lowest mortality (20%) indicating highest protection (Relative Percent Survival 76.5%) from P. fluorescens infection than 2%, 4% and 6% doses diets that resulted 60%, 45% and 25% mortalities respectively. Eight percent (8%) dose also showed highest growth (36g) compare to other doses. The results are suggested that the dietary supplementation of P. guajava leaf extracts act as immunostimulants, reduce mortality and disease resistance in O. niloticus against P. fluorescens.