Fig. 3. Uricase (A), allantoinase (B), allantoicase (C) and ureidoglycollate lyase (UGL, D) 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 3–6 samples for uricase and allantoinase. Allantoicase and UGL activity are the means ± S.D. of three samples, except at 54, 99, 120, 170 194, 217 and 313h post-fertilization for fed larvae (N=2, ± range). CYA, complete yolk absorption; ND, not detectable.