The Effects Of Magnesium On Performance And Mineral Element Contents In Tissues And Tibia Of Layer

1. With the increase of age. both of tibia length and weight were increased but the increase of length and weight were slower after 13 and 20 weeks. Ca and P contents in tibia, bone ash/fish bone were increased rapidly from the 17th to 19th week.. Changing curves of Ca and P were similar. Na content was higher than Mg content. Na and Mg contents from the 17th to 19th week were increased rapidly. Changing curves of Na and Mg were similar. Changing cwve of K content was not the same as Na and Mg. With the increase of age, K content decreased, after 23?4 weeks the change tended to be smooth, and Mn content increased. but after 45 weeks, Mn content decreased. Changing curve of Fe was irregular. 2. Effects of low dietazy Ca and high Mg on tibia growth of chicks were studied. The results showed that Mg content in tibia was significantly increased, Fresh tibia weight and Ca content in tibia was significantly decreased by high Mg in normal or low Ca diet. Fresh tibia length and weight, compressive strength. content of bone ash were decreased by high Mg in low Ca diet. The ratios of calcium: phosphorus. calcium: magnesium. phosphorus: magnesium were decreased by high Mg in normal or low Cadiet. Effects of low dietaiy P and high Mg on tibia growth of chicks were studied. The results showed that Mg content in tibia was significantly increased, but Ca and P contents, the ratios of Calcium: phosphorus, calcium: magnesium, and phosphorus: magnesium in tibia were significantly decreased. and fresh tibia weight was significantly decreased by high Mg in normal P diet. Mg content in tibia was significantly increased. Ca and P contents in tibia were significantly decreased, and fresh tibia length and weight. compressive strength. content of bone ash were significantly decreased by high Mg in low P diet. 3. Effects of magnesium on tibia of the chick were studied with corn-soybean cake supplemented with magnesium. The results showed that Mg content in tibia was significantly increased, Ca and P contents in tibia were significantly decreased, the ratios of calcium: phosphorus. calcium: magnesium, and phosphorus: magnesium were deceased. Photograph of X-ray showed that bones were loose by high Mg. Electron microscope examination indicated a bone tissue hyperplasia, decreased fresh tibia compressive strength by high Mg (supplement with magnesium 6000mg/kg MgO). Effects of magnesium on tibia of growing chickens were studied with corn-soybean cake supplemented with magnesium. The results showed the decreased sodium, calcium and phosphorus contents and the ratios of calcium: phosphorus. calcium: magnesium and phosphorus: magnesium in tibia caused by high Mg during 1 weeks recovered normal by changing from high Mg to normal diet on growing chickens during 8- 16 weeks.Effects of magnesium on performance of laying hens were studied with corn-soybean cake (supplemented with magnesium 6000mg/kg MgO). The results showed that length and weight of tibia in high magnesium group were decreased. and this was more significant in the old than in the young layer. Magnesium contents of tibia in high magnesium group were high. but ash contents of tibia, ratios of calcium: phosphorus. calcium: magnesium and phosphorus: magnesium were low. 4. The effects of magnesium level (1.Control group 0.00mg/kg MgO, C; 2. Medium magnesium group 1200 mg/kg, MgO, M; 3. High magnesium group 6000 mg/kg, MgO, H) on the chicks were studied with conventional diet. The results showed that magnesium content in blood was higher in H group ti-ian that inC and...