Effect of dietary zinc deficiency on alkaline phosphatase and nucleic acids in rats

Weanling male albino rats were randomly alloted to zinc deficient fed (ZnDF) pair-fed (ZnPF) or ad libitum-fed (ZnAL) dietary treatments. The rats were fed diets with either low (5 micrograms/g) or adequate (100 micrograms/g) zinc for 28 days. Zinc deficiency significantly reduced growth rate by 60% and was associated with a significantly low feed intake when compared with ZnPF and ZnAL groups. DNA and RNA contents of the liver were used as indication of nitrogen metabolism. DNA content was similar for both ZnPF and ZnAL groups (1.90 and 2.20 mg/g wet weight, respectively), but significantly different from ZnDF (1.42 mg/g wet weight). Liver RNA values of ZnAL, ZnPF and ZnDF groups similarly varied (25.0, 20.2 and 14.8 mg/g wet weight, respectively). Liver, muscle, spleen, femur and serum zinc concentrations were lowest in rats fed ZnDF relative to adequate zinc levels. The levels of the alkaline phosphatase activity was highest in the serum and lowest in the brain (spleen value was greater than that of the liver). Alkaline phosphatase activity was similar in ZnAL and ZnPF groups, but significantly different from ZnDF. In conclusion, the constitutively expressed growth rate, DNA level, RNA level, organ/serum zinc contents and alkaline phosphatase activities were markedly affected by zinc deficiency in rats.