Some histochemical observations on zinc deficiency in chickens

Histochemical examination of tissues from chickens maintained from hatching on experimental zinc-deficient diets, showed that enlargement of the nucleoli of the crop epithelium was associated with increased amounts of RNA in that organelle. The layers of mucosubstance-coated prickle cells near the lumen of the crop were reduced in number and this pericellular, PAS-positive and colloidal iron-staining material was sometimes less distinct round the remaining prickle cells. Ten enzymes were examined in various tissues but only alkaline phosphatase in the stratum basale of the crop and oesophagus and in the tarsometatarsal epiphyseal cartilage, and alcohol dehydrogenase in similar regions of the crop and oesophagus, were severely depleted. The reaction for NADH diaphorase was moderately less intense in the crop and oesophageal epithelium.