This study investigated the growth and haematological response of Clarias gariepinus to different concentration of garlic supplemented diet for a period of 12 weeks. This study was carried out in 2011 in the premises of Fisheries Department, Delta State University, Asaba, Nigeria. The experimental diet was formulated to contain 0% (control), 0.5%, 1% and 3% garlic. Fish were sorted into four groups based on the diet and were fed 3% live body weight. Diets which contain garlic did not show a significant effect (P = 0.06) on the weight of C. gariepinus. However, fish fed diets containing garlic had a higher (P <0.001) total length compared to the control. Nevertheless, fingerlings fed 0.5% concentration of garlic in diet exhibited greater growth in terms of weight and length compared to fingerlings in all other treatment groups and the control. At the end of the experiment, the total red blood cell count (RBC), white blood cell count (WBC), haemoglobin (Hb) and packed cell volume (PCV) of fish in the garlic supplemented groups were greater (P <0.05) compared to the values prior to the commencement of the experiment and to the control. However, catfish fed 0.5% garlic diet were observed to have a higher value of RBC, PCV and Hb than the other concentrations. Increment in plasma protein was noted in catfish fed garlic supplemented diet than the control. This study demonstrates that garlic supplemented feed stimulates increment in both total length and haematological indices of fish. Supplementation of fish feed with garlic is therefore of high benefit in aquaculture as it boosts the ability of C. gariepinus to resist diseases.

This gonad enhancement study investigates the effect of different fresh and formulated feeds and feeding regimes on the growth and gonad quality of wild‐collected adult sea urchin, Tripneustes gratilla, under farm conditions for over 18 weeks. In the first 12 weeks (phase 1), urchins were fed fresh Ulva rigida (U); a 50:50 mixture of fresh U. rigida and Gracilaria gracilis (UG); fresh G. gracilis (G) and a formulated diet 20U (containing 20% U. rigida), and in the final 6 weeks (phase 2) of the study, diet was changed to a formulated feed (20U diet). By the end of phase 1, urchins fed the 20U diet produced gonads (50.72 ± 5.4 g) that were significantly heavier (p < .001) than the gonads of urchins fed the fresh seaweed diets (U, UG & G). By the end of phase 2, gonad weight of urchins in treatment groups UG‐20U and G‐20U were similar to those fed the 20U‐20U diet. Gonad colour of urchins in the G‐20U treatment became significantly lighter (ANOVA, p = .029) and poorer quality, compared with urchins in the U‐20U group. This gonad enhancement study, conducted on wild‐collected adult T. gratilla, has shown that a formulated feed (20U diet) can enhance gonad growth and produce commercially acceptable gonads. This farm‐based study supports previous findings from aquarium‐based studies by our group and indicates that short‐term sea urchin gonad enhancement can be carried out under farm conditions in South Africa.