THE EFFECTS OF DIETARY PHOSPHORUS AND CALCIUM TO PHOSPHORUS RATIO ON THE ACTIVITIES OF ALKALINE PHOSPHATASE AND SERUM CALCIUM AND PHOSPHORUS IN MINIATURE—PIGS(XIANG PIG)

The effects of dietary phosphorus and calcium:phosphorus ratio on the activities of alkline phosphatase(AKP) in the serum,duodenum and the sixth rib and on serum phosphorus and calcium levels were evaluated using thirty-six growing castrated Xiang pigs,in a 3×3 factorial trial involving nine diets.The basal diet of corn,soybean,blood meal and alfalfa meal contained 0.29% calcium and 0.30% phosphorus.For the nine treatment diets,phosphorus levels of 0.3%,0.6% and 0.9% were combined with calcium:phosphorus ratios of 1:1,1.25:1 and 1.5:1.Levels of dietary phosphorus and calcium:phosphorus ratio in the diets were adjusted with CaCO3,Na2HPO4 and CaHPO4.The activity of AKP in the serum and in the sixth rib reduced significantly as dietary phosphorus level increased from 0.3% to 0.9%(P0.05),but the activity of duodenal AKP and serum calcium level were not affected by different levels of dietary phosphorus.There were no effects of calcium:phosphorus ratio on AKP activity in serum,duodenum or the sixth rib(P0.05).Serum phosphorus level increased as dietary phosphorus increased and decreased as dietary calcium to phosphorus ratio increased.Serum calcium level was highest with the 1.25:1 calcium:phosphorus ratio.