Zinc Concentration in Rat Hair During Zinc Depletion and Repletion

The study investigated the zinc concentration in the hair of weaned male rats under zinc deficiency and supplementation. Rats were fed a semi-synthetic diet with varying zinc levels, and the zinc content in their hair was monitored. Extreme zinc deficiency (1.9 ppm) led to temporary reductions in hair zinc levels due to halted hair growth and hair loss over 35 days. Incremental zinc additions (2–8 ppm) resulted in reduced hair zinc levels as new zinc-deficient hair grew with increasing body weight. Only at sub-optimal zinc levels for hair production (8–12 ppm) did hair zinc levels increase with more zinc. A plateau was observed between 15 and 100 ppm. The study concluded that hair zinc levels were not a reliable indicator of overall zinc status in farm animals due to inconsistent correlations with other zinc distribution criteria.