Magnesium deficiency, requirement and toxicity in the young Japanese quail.

Studies of magnesium deficiency, requirement and toxicity in the young Japanese quail (Coturnix coturnix japonica) were conducted. Day-old birds were fed an adequate purified diet containing 35% soy protein to 2 weeks of age. Residual magnesium in the diet without any added magnesium salts was 21 p.p.m. magnesium was supplied by graded amounts of MgSO4 to a total of 11 levels ranging from 125 to 2,000 p.p.m. Deficiency signs included poor growth, and occasionally excitability, gasping and convulsions. Most mortality occurred during the first 7 days. The maximum dietary magnesium concentrations that produced the minimal significant deviation from normal values for mortality, body weight, hemoglobin and tibia ash was 225, 200, 250 and 250 p.p.m., respectively. Based on these measurements, 300 p.p.m. magnesium is considered adequate to meet the young quail's requirement under the conditions of these experiments. With 2,000 p.p.m. magnesium, the only adverse effect was an increase in mortality. Between 200 and 1,000 p.p.m. magnesium there was a linear relationship between concentration of magnesium in the tibia and the log of the concentration of dietary magnesium. This suggests that tibia magnesium concentration might be useful for bioassay of magnesium in foodstuffs.