【作者】 孟海燕；

【导师】 苏晓鸥； 杨开伦；

【作者基本信息】 新疆农业大学 ， 动物营养与饲料科学， 2004， 硕士

【摘要】 本论文研究了肉仔鸡日粮中5种铬源的相对生物学利用率及其对肉鸡胴体、肉质、排泄物和组织中铬含量的影响，对5种铬源在高添加水平下对肉鸡生长性能和组织铬含量的影响作了进一步的研究，以此综合评价了肉仔鸡日粮中5种铬源对肉鸡生长性能、胴体品质和食用安全性的影响。试验一：肉仔鸡日粮中不同铬源相对生物利用率的研究 0～3周龄AA肉仔鸡玉米+豆粕型基础日粮中分别添加5种铬源，吡啶甲酸铬（CrPic）、烟酸铬(CrNic)、酵母铬(CrY)、蛋氨酸铬(CrMet)和氯化铬(CrCL3)，5个水平：0、0.2、0.4、0.8、1.6mgCr/kg。常规饲养免疫，试验结束屠宰取肝脏、肾脏和胫骨，应用AAS测定组织铬含量。结果表明：1.日粮中以0~1.6 mgCr/kg水平添加5种铬源，对0～3周龄肉仔鸡的日采食、日增重、料重比以及腹脂率均无显著影响（P＞0.05），因此本试验中生长性能不宜作为以斜率比法评价铬源相对生物利用率的敏感指标；但是均可显著增加0～3周龄肉仔鸡的肝脏、肾脏和胫骨铬含量（P＜0.05），并且各组织铬含量随日粮添加铬水平的升高而线性升高（P＜0.001）；肝脏和胫骨铬含量更适宜作为以斜率比法测定铬源相对生物利用率的敏感指标。2.以肝脏、肾脏和胫骨铬含量为指标，计算得出3周龄肉仔鸡对四种有机铬源的相对生物学利用率以CrPic、CrNic、CrY、CrMet为序分别为：肝脏铬含量：103.57%、107.32%、101.40%、91.62%；肾脏铬含量：108.88%、110.12%、103.25%、105.86%；胫骨铬含量：59.27%、44.12%、117.04%、64.11%。3.以肝脏和肾脏铬含量为敏感指标，肉仔鸡对5种铬源的相对生物利用率无显著差异；以胫骨铬含量为敏感指标，肉仔鸡对CrY的相对利用率显著高于CrPic、CrNic、CrMet一倍。因此可推断CrY是较好的铬源。试验二：不同铬源对肉鸡胴体和肉质的影响 0～6周龄AA肉仔鸡玉米+豆粕型基础日粮中分别添加5种铬源CrPic、CrNic、CrY、CrMet 、CrCL3，2个水平：0.2、0.4mgCr/kg，试验结束统计日增重、屠宰率以及肌肉蛋白含量和肉色、系水力等肉质指标。结果表明： 1.0.4mgCr/kg的CrY可提高0～6周龄肉鸡日增重5.04％，降低料重比5.29％（P＜0.05），在3周龄无显著影响，而CrPic、CrNic、CrMet 、CrCL3均无促进作用。2.日粮添加5种来源的0.2、0.4mg/kg三价铬均不能提高6周龄肉鸡屠宰率、全净膛率、胸肌率和腿肌率（P＞0.05），也不降低腹脂率（P＞0.05）。3. 在0.2、0.4mg/kg添加水平下，CrNic、CrY、CrMet和CrCL3显著增加6周龄肉鸡的肉色和嫩度（P＜0.05），CrPic没有显著影<WP=9>响。4.日粮中以0.2、0.4mg/kg水平添加5种铬源对6周龄肉鸡肌肉蛋白和脂肪含量没有显著影响，但CrPic、CrNic、CrY、CrCL3可显著降低肝脏脂肪含量16.50％～22.08％（P＜0.05）。5.肉仔鸡日粮添加三价铬可促进生长性能、增加鸡肉肉色和嫩度、降低肝脏脂肪含量，但是效果的发挥取决于铬源以及添铬时间跨度。试验三：不同铬源对肉鸡排泄物和肌体组织铬含量的影响 在试验2的基础上，试验结束前6天开始收粪，试验结束将每重复笼6天的粪样混合均匀，屠宰取胸肌和肝脏，以AAS测铬。结果表明：日粮添加0.2、0.4mg/kg的5种铬源形式的三价铬，使6周龄肉鸡肝脏和肉品中的铬含量显著升高（P＜0.05），最高分别达0.591mg/kg，0.661mg/kg，但是尚未超过国家食品铬含量限量标准1mg/kg（GB14961-94）；因此，添加铬生产的鸡肉不会使铬过量而造成毒性，是安全的。试验四: 不同铬源在高添加水平下对肉鸡生长性能和组织铬含量的影响0～3周龄AA肉仔鸡日粮添加8mgCr/kg的5种铬源,一个对照组,统计日增重和日采食，取肝脏、肾和胫骨测定铬含量。结果表明：1.在高添加水平8mgCr/kg下，日粮添加铬对3周龄肉仔鸡生长性能的不良影响取决于铬源。CrY对3周龄肉仔鸡的日增重、日采食和料重比没有不良影响（P＞0.05），但是CrPic、CrNic、CrMet和CrCL3均对3周龄肉仔鸡有不同程度的不良影响，在高水平8mgCr/kg下分别使肉仔鸡的日增重显著下降8.06%，16.46%，9.06%，41.36%（P＜0.05）；CrMet显著增加肉仔鸡日采食11.33％，而CrCL3显著降低肉仔鸡日采食17.04％；CrNic、CrMet和CrCL3使肉仔鸡的料重比显著升高20％，22％，41.33％。可见CrMet和CrCL3影响最大，其次为CrNic和CrPic。2.8mgCr/kg CrCL3显著增加3周龄肉仔鸡的腹脂率63.01%（P＜0.05），其它四种铬源对3周龄肉仔鸡的腹脂率没有显著影响（P＞0.05），表明高添加的条件下有机铬对肉仔鸡腹脂蓄积的影响比无机铬小。3.在高添加水平条件下，铬源对1～21日龄肉仔鸡的肝脏铬含量、肾脏铬含量、胫骨铬含量有极显著影响（P＜0.01）。从肉仔鸡对不同铬源的生物利用率、促生长和改善肉质作用、人类食品和土壤环境安全性、高添加毒性安全性进行综合评价，CrY是相对较好的铬源，在肉仔鸡玉米+豆饼日粮中以0.4 mgCr/kg添加水平为宜。更多还原

【Abstract】 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. <WP=11>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更多还原