The Dynamic Relationship Of Cadmium Residues In The Body Tissues With The Content Of Cadmium In The Dietary Of The Growing-Finishing Pigs

The dynamic relationship of cadmium residues in the body tissues with the content of Cadmium in the dietary of the growing-finishing pigs was investigated in this study. In the experiment, eighty-four Doroc×Landrance×Yorkshire(DLY) piglets averaging 20kg were assigned to seven dietary treatment in a single factorial arrangement during 20～100kg weight stage. Pigs received a diet containing 0, 0.2, 1.0, 5.0, 10mg Cd/kg diet respectively.The results showed that1. The supplementation of 0.2～10mg Cd/kg diet could decrease growth performance of growing～finishing pigs.Compared to the control group,ADG decreased by 13.33-18.89%.The regression equations of the ADG(y₁,g) and F/G(y₂) with the cadmium supplementation(x,mg/kg) is:y₁=727.37-25.926x+1.7589x²(R²=0.504,P=0.496);y₂=2.2062+0.1081x-0.0114x²(R²=0.721,P=0.279).According to the regression equations,the highest ADG could be achieved when the cadmium supplementation is 0mg/kg,the lowest F/G could be gotten when the cadmium supplementation is 0mg/kg.2. The supplementation of 0.2～10mg Cd/kg diet could increase cadmium residues in the body tissues in different extent. The cadmium content in the muscle, liver and kidney tended to increase with the increase of the cadmium supplementation.The regression equations of the cadmium content in the muscel(y₃,mg/kg) with the cadmium supplementation(x,mg/kg) is:100kg, y₃=0.0071+0.0059x-0.0001x² (R²=0.965,P=0.035).From the regression equations,if the cadmium content in the muscel(y₃) don't exceed 0.05mg/kg, the cadmium supplementation(x) couldn't exceed 8.49mg/kg when the pigs were slaughtered at 100kg.The regression equations of the cadmium content in the liver(y₄,mg/kg) with the cadmium supplementation(x,mg/kg) is:70kg, y₄=0.0575+0.9956x-0.0360x² (R²=0.998,P=0.002);100kg, y₅=0.2019+1.1864x-0.0304x² (R²=0.997,P=0.003). According to the regression equations,if the cadmium content in the liver(y₄) don't exceed 0.5mg/kg, the cadmium supplementation(x) couldn't exceed 0.45mg/kg when the pigs were slaughtered at 70kg; if the cadmium content in the liver(y₅) don't exceed 0.5mg/kg, the cadmium supplementation(x) couldn't exceed 0.25mg/kg when the pigs were slaughtered at 100kg.The regression equations of the cadmium content in the kidney(y₆,mg/kg) with the cadmium supplementation(x,mg/kg) is:70kg, y₆=0.4273+1.4497x-0.0543x² (R²=0.979,P=0.021);100kg, y₇=0.5279+2.0469x-0.0538x² (R²=0.999,P=0.001)From the regression equations,if the cadmium content in the kidney(y₆) don't exceed 1.0mg/kg, the cadmium supplementation(x) couldn't exceed 0.40mg/kg when the pigs were slaughtered at 70kg; if the cadmium content in the liver(y₇) don't exceed 1.0mg/kg, the cadmium supplementation(x) couldn't exceed 0.23mg/kg when the pigs were slaughtered at 100kg.On the basis of all the above-mentioned,it is the best that the cadmium content in diet is 0mg/kg.3. The relationship of the cadmium content among the muscel,the liver and the kidney is: the kidney＞the liver＞the muscel. The significant positive correlation exsits among the three (p＜0.05).