Estimation Of The Ralative Bioavailability Of Different Chromium Sources And Their Effects On Carcass And Meat Quality In Broliers

The individual ralative bioavailability and their effects of the 5 chromium sources in broliers diet were studied on performance and meat quality and Cr content in excrements and tissues, and their effects were further studied on performance and Cr content in tissue at high Cr supplementation levels. The effects of the 5 chromium sources were systemically evaluated on broiler performance, meat quality and its safety as food. Experiment 1: Estimation of the ralative bioavailability of different chromium sources in broilers Corn+bean based diet were fed to 0～3 week-old broliers in which 5 chromium sources (chromium picolinate (CrPic), chromium nicotinate (CrNic), chromium yeast (CrY), chromium methionine (CrMet), chromium cholorid (CrCL3) at 4 levels (0.2, 0.4, 0.8, 1.6mg/kg) were respectively added. The control group was fed diet without adding Cr. The performance and the Cr content in liver, kidney and tiber were determined. The results were as follows: 1. Any 5 Cr sources added at levels of 0～1.6mgCr/kg had no significant effects on the daily feed intake (FI), daily weight gain (DWG) and the ratio of FI to DWG and adominent fat ratio (P＞0.05). So the performance was not regarded as the propriate criteria to estimate the relative bioavailability of different chromium sources in broilers. But Any of 5 Cr sources added at levels of 0～1.6mgCr/kg increased the Cr content in liver; kidney and tiber(P＜0.05)with the increasing diet Cr levels(P＜0.001). Therfore, the Cr contents in liver and tiber were the more propriate index to estimate the relative bioavailability of different chromium sources in broilers. 2. The relative bioavailability of four Cr sources (CrPic, CrNic, CrY, CrMet) in 0～3 week-old broliers was 103.57%, 107.32%, 101.40% and 91.62%,respectively, based on Cr content in liver；the corresponding values were 108.88%, 110.12%, 103.25%, 105.86% in kidney and 59.27%, 44.12%, 117.04%, 64.11% in tiber. 3. With the Cr content in liver and kidney as index, the relative bioavailability of the four Cr sources had no significant differences with the control group; But with the Cr content in tiber, the relative bioavailability of CrY was significantly one fold more than of the other three organic Cr sources. So it was postulated that CrY was the best among the four organic Cr sources. Experiment 2: The effects of different chromium sources on carcass and meat quality of broilers Corn+bean based diet added five chromium sources at the levels of 0.2 and 0.4 mgCr/kg were respectively fed to 0～6 week-old AA broilers shared the same control without any chromium source addition. The results indicated: 1.The diet added CrY at the level of 0.4mgCr/kg did have significant effects on increasing the daily weight gain( FI ) by 5.04% and decreasing the ratio of FI to DWG by 5.20%(P＜0.05), but the other sources did not. 2.The diets added any 5 soruces at the levels of 0.2 and 0.4mgCr/kg had insignificant effect on slaughter ratio, full carcass rate, breast weight rate, leg weight rate and adominent fat rate(P＞0.05) of the 6 week-old broliers. 3. CrNic, CrY, CrMet and CrCL3 added at the levels of 0.2,0.4mgCr/kg had siginficant positive effects on the chicken color and tender degree, but CrPic did not (P＞0.05). 4. Any of the 5 Cr sources added at the levels of 0.2, 0.4mgCr/kg had insignificant effects on the muscle protein and fat content of the 6 week-old broliers, and CrPic, CrNic, CrY and CrCL3 had significant effects on decreasing the liver fat content by 16.50％～22.08％(P＜0.05). 5.The diets added trivalent Cr had active effects on the performance, chicken color and chicken tender, and decreasing the liver fat content, but the effects depended on the added Cr sources. Experiment 3: The effects of different Cr sources on the Cr content in the excrements and the tissues of broliers The experiment was based on the experiment 2. The excrements 6 days before the end of the trial were collected, and the Cr content in breast muscle, the liver and the excrements were determined. The diets added any of...