Effect of dietary Artemisia afra on growth, some innate immunological parameters in Clarias gariepinus challenged with Aeromonas hydrophila

This study investigated the effect of Artemisia afra-based on growth, haemato-biochemical parameters and disease resistance in Clarias gariepinus (African sharptooth catfish). Five diets were formulated to contain 0%, 3%, 6%, 9% and 12% of A. afra, designated as the control, D2, D3, D4 and D5, respectively. Each diet was fed to triplicate groups of 45 fish (32.49 +/- 0.27 g). All groups were fed ad libitum twice a day at 09:00 h and 15:00 h for 45 days. There were no significant differences (P > 0.05) in feed conversion ratio and specific growth rate of fish between dietary treatments. Feed conversion ratio values increased from 1.64 in the control to 1.78 in D5. Specific growth rate values were lower in D5 (1.94) than in the control (2.02). White blood cells increased with increasing dietary A. afra inclusion levels from 3.61 (x 10(3)/mu l) in the control to 5.05 (x 10(3)/mu l) in D5. Similarly, red blood cells increased from 2.07 (x 10(6)/mu l) in the control to 3.26 (x 10(6)/mu l) in D4. Haemoglobin, haematocrit, mean corpuscular volume, mean corpuscular haemoglobin and mean corpuscular haemoglobin concentration also increased with higher A. afra inclusion levels. No significant changes (P > 0.05) were observed in alanine transaminase, aspartate transaminase, alkaline phosphatase and lactate dehydrogenase levels between dietary treatments. Fish fed with D3, D4 and D5 had significantly higher (P < 0.05) nitro blue tetrazolium and lysozyme activity compared to fish fed with the control and D2. After a challenge trial using the most virulent dosage (4 x 10(6) cfu ml(-1)) of Aeromonas hydrophila, survival rate was lower in fish fed with the control (20%), D2 (30%) and D3 (40%) compared to fish fed with D4 (70%) and D5 (70%). This shows that A. afra can improve the health status of captive C. gariepinus.