铬源和铬添加水平对热应激肉仔鸡血清生化指标、体脂沉积及免疫器官指数的影响

Effects of chromium sources and adding levels of chromium on serum biochemical indexes,body fat deposition and immune organ indexes of broiler chicks under heat stress

为了研究饲粮中添加不同铬源和铬添加水平对42日龄热应激肉仔鸡血清生化指标、体脂沉积及免疫器官指数的影响,试验选用252只1日龄体重均一的科宝(Cobb 500)雌雏肉鸡,随机分成7个处理组,每组6个重复,每个重复6只鸡,对照组饲喂玉米-豆粕型基础饲粮(含铬0.37 mg/kg),试验组分别饲喂在基础饲粮中添加0.4,2.0 mg/kg的丙酸铬(CrPro)、吡啶甲酸铬(Cr Pic)和三氯化铬(CrCl_3)的试验饲粮。结果表明:与对照组相比,试验组显著提高了42日龄热应激肉仔鸡血清碱性磷酸酶(AKP)活性(P=0.018);降低血清总胆固醇(TC)浓度(P=0.021),并且热应激肉仔鸡血清TC浓度随铬添加水平的升高而降低(P<0.001);铬源和铬添加水平互作能提高42日龄热应激肉仔鸡血清高密度脂蛋白胆固醇(HDLC)含量(P=0.002),以0.4 mg/kg CrPro效果最好。铬对其他血清生化指标无影响(P>0.05)。与对照组相比,试验组热应激肉仔鸡腹脂率显著降低(P=0.025),CrCl_3降低42日龄热应激肉仔鸡胸肌肌内脂肪效果优于CrPro和Cr Pic(P=0.071);但是铬对肝脏脂肪含量没有影响(P>0.05)。与对照组相比,试验组热应激肉仔鸡法氏囊指数显著提高(P=0.041),但脾脏指数和胸腺指数无显著变化(P>0.05)。Cr Pic对法氏囊的增重效果优于CrPro和CrCl_3(P=0.008);添加2.0 mg/kg的铬能明显提高热应激肉仔鸡脾脏指数(P=0.008)。说明铬能提高热应激肉仔鸡血清AKP活性,降低TC浓度,改善体脂沉积,提高法氏囊指数,且CrPro和Cr Pic优于CrCl_3。

To investigate the effects of adding different chromium （Cr） sources in the diets and the adding levels of Cr on serum biochemical in- dexes, body fat deposition and immune organ indexes of 42 - day - old broiler chicks under heat stress, a total of 252 one - day - old Cobb fe- male broiler chicks were randomly divided into 7 treatments with 6 replicates of 6 chicks each. The control group was fed basal corn - soybean meal diet containing 0.37 mg/kg Cr, and the experimental groups were fed basal diet supplemented with 0.4 or 2.0 mg/kg chromium propio- nate（ CrPro）, chromium picolinate （CrPic）, and chromium chloride （CrC13 ）, respectively. The results showed that serum alkaline phespha- tase （AKP） activity in 42 - day - old broiler chicks in the experimental groups under heat stress was significantly increased （ P = 0.018 ） com- pared with the control group, and the serum total cholesterol （TC） concentration was decreased （ P = 0. 021 ）, while serum TC concentration in the broiler chicks under heat stress was significantly decreased （ P 〈0. 001 ） with the increase of adding levels of Cr. The interaction between Cr sources and adding levels of Cr could increase the serum high density lipoprotein Cholesterol （ HDL - C ） content in 42 - day - old broiler chicks under heat stress （ P =0. 002）, and the 0.4 mg/kg CrPro had the best effect. However, Cr had no effect on other serum biochemical indexes （ P 〉 0, 05 ）. The abdominal fat percentage of the broiler chicks in the experimental groups under heat stress was significantly decreased （ P = 0. 025 ） compared with the control group, and the effect of CrCI3 reducing the intramuscular fat of breast muscles of 42 - day - old broiler chicks under heat stress was better than CrPro and CrPic （ P = 0.071 ）, but Cr had no effect on liver fat percentage （ P 〉 0.05 ）. The index of bursa of fabricius in the broiler chicks in the experimental groups under heat stress was significantly increased （ P = 0. 041 ） compared with the control group, but there were eo significant changes （ P 〉 0.05） in the spleen index and thymus index. CrPic was better than （ P = 0. 008） CrPro and CrCl3 on the effect of weight gain in bursa of fabricius, while adding 2.0 mg/kg Cr could obviously increase （P = 0. 008 ）the spleen index of broiler chicks under heat stress. The results indicate that Cr can increase serum AKP activity, reduce TC concentration, improve body fat depo- sition, and increase the index of bursa of fabricius in broilers chicks under heat stress, while CrPro and CrPic are better than CrCl3.