Negative Effect Of Chromium Added To Diet On Pig Breeding

Heavy metal pollution is a significant issue which limited non-environmental pollution pork. However, it has not been highly valued, and it is short of thoroughly and systematical studies. The study reported was conducted to evaluate the negative effects of chromium on ADFI, kindneys, livers in growing and finishing pigs. Chromium tripicolinate (CrPic) is a kind of organic chromium complex.A total of 84 crossbred pigs were divided into 7pens, 12 pigs every pen. Three pens of pigs were offered a control diet (maice-soybean, meal) and others were offerd control diet supplemented with 0.2 mg/kg, 1 mg/kg,5 mg/kg and 10 mg/kg CrPic.During the trial, all pigs were given free access to feed and waters.7 pigs from each treatment were selected to collect tissue samples after 40 days, 80 days and 110 days on trial. The chromium redidues of tissue samples were analysised. The viscera coefficient of the livers and kindneys were stated. During the feeding trial, the daily behavior and diet of the pigs were also noted for further research.The results showen that the additions of 0.2 mg/kg CrPic significantly increase the ADFI of the pigs during the second feeding trial, and the addition of 5 mg/kg CrPic significantly increase the ADFI of the pigs during the second and the third feeding trial.The results suggest that the addition of o.2 mg/kg and 5mg/kg CrPic to the trial diets increase the viscera coefficient of the livers .By contraries, the addition of 1 mg/kg and 10 mg/kg CrPic to the trial diets reduce the viscera coefficient of the livers.Chromium residue levels of tissue were significantly increased in pig offerd the diets supplemented with 5 mg/kg and 10 mg/kg CrPic, especially the liver. According to the station standard MLs of contamination in food, the chromium residue levers of tissue in pigs which go through the whole feeding trial were unqualified.Synthesize those experiments' results: During the 20 kg～80 kg phase,the addition of more than 5mg/kg CrPic to the trial diets will lead to the cumulation of chromium in pork ,livers and kidneys. During the 20kg～110kg phase,the addition of more than 5mg/kg CrPic to the trial diets will lead to the significantly cumulation of chromium in pork ,livers and kidneys. With feed in which chromium contents exceed 3.1 mg/kg , during the 20kg～110kg phase, chromium residue in pig tissues will go beyond the limit of state standard. It is suggested that chromium complex be added to feed only during the period of stress or at area of short of chromium. It is also suggested that chromium contents in pig feed of Hygienic standard be reduced to lower than 3mg/kg.