Fig. 7. Glutamine synthetase (GSase, A), ornithine carbamoyl transferase (OCTase, B) and arginase (C) activity in whole-animal crude extracts during early development and in selected adult tissues (columns) of Clarias gariepinus. Filled triangles, whole embryos and yolk-sac larvae; filled circles, larvae fed Artemia; open circles, starved larvae. Values are means ± S.D. of assays on 3–4 samples, except for fed larvae at 79 and 119h post-fertilization (N=2, ± range). CYA, complete yolk absorption.