IMMUNOSTIMULATORY INFLUENCE AND DEVELOPMENT OF NON-SPECIFIC IMMUNITY OF NILE TILAPIA Oreochromis niloticus AGAINST Aeromonas hydrophila USING GARLIC

The study evaluated the efficacy of the different garlic constituents as immunostimulant  to Nile Tilapia Oreochromis niloticus . Specifically, the study aimed to determine the immune response of Nile Tilapia  fed diets containing different parts of garlic (whole garlic, garlic peel and garlic bulb) and its resistance against Aeromonas hydrophila infection. Treated fish were fed with diets containing 5% garlic  within four weeks. Vitamin C serves as the positive control treatment while the negative control was treated with distilled water. The different haematological parameters as white blood cell. red blood cell, haemoglobin haematocrit and platelet counts were determined during 0, 14, 20, and 28 days pre and post immunization. After the feeding experiment, fish were challenged with A. hydrophila and survival was monitored.

Result showed that WBC, RBC, HGB, HCT and PLT in fish fed garlic diets at dietary inclusion level of 5% showed significantly higher values among treatments. The same results were observed on the survival of tilapia against the infection. Conversely, high levels of supplementation of garlic as immunostimulant did not significantly affect the non specific immunity of the tilapia. These results further suggests that use of lower than 5%  garlic via oral administration as immunostimulant to nile tilapia will be considered for future feed formulations.