Effects of Garlic (Alliumsativum) and chloramphenicol on growth performance, physiological parameters and survival of Nile tilapia (Oreochromis niloticus)

We studied and compared the effects of chloramphenicol antibiotic and garlic (Allium sativum), used as immunostimulants and growth promoters, on some physiological parameters, growth performance, survival rate, and bacteriological characteristics of Nile tilapia (Oreochromis niloticus). Fish (7±1g/fish) were assigned to eight treatments, with three replicates each. Treatment groups had a different level of Allium sativum (10, 20, 30, and 40g/kg diet) and chloramphenicol (15, 30, and 45mg/kg diet) added to their diets; the control group diet was free from garlic and antibiotic. Diets also contained 32% crude protein (CP) and were administered at a rate of 3% live body weight twice daily for 90 days. Results showed that the final weight and specific growth rate (SGR) of O. niloticus increased significantly with increasing levels of Allium sativum and chloramphenicol. The highest growth performance was verified with 30g Allium sativum / kg diet and 30mg chloramphenicol / kg diet. The lowest feed conversion ratio (FCR) was observed with 30g Allium sativum / kg diet and 30mg chloramphenicol / kg diet. There were significant differences in the protein efficiency ratio (PER) with all treatments, except with 45mg chloramphenicol / kg diet. No changes in the hepatosomatic index and survival rate were observed. Crude protein content in whole fish increased significantly in the group fed on 30g Allium sativum / kg diet, while total lipids decreased significantly in the same group. Ash of whole fish showed significantly high values with 30g Allium sativum and 15mg chloramphenicol / kg diet while the lowest value was observed in the control group. Blood parameters, erythrocyte count (RBC), and hemoglobin content in fish fed on diets containing 40g Allium sativum and all levels of chloramphenicol were significantly higher than in control. Significantly higher hematocrit values were seen with 30 and 45mg chloramphenicol / kg diet. There were no significant differences in the mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC). Plasma glucose decreased significantly with increasing levels of Allium sativum but increased significantly with increasing levels of chloramphenicol. Total lipids were significantly reduced with diets containing 40g Allium sativum and 30mg chloramphenicol / kg diet, while total plasma protein content was significantly higher in fish fed on diets containing 10, 20, and 30g Allium sativum, and 30 and 45mg chloramphenicol / kg diet. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities in plasma decreased significantly with increasing levels of Allium sativum and chloramphenicol. All Allium sativum and chloramphenicol levels decreased total bacteria and coliforms in water, muscles and intestine when compared to the control group. Treated groups had lower mortality rate than the control group during the challenge test. In conclusion, it can be suggested that adding 3% Allium sativum to fish diet can promote growth, reduce total bacteria, and improve fish health.