本试验旨在研究饲粮添加不同铬源和铬水平对1~3周龄热应激肉仔鸡生长性能、胴体性能及肉品质的影响。选用1日龄科宝白羽雌雏肉仔鸡252只,随机分为7个组,每组设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上添加0.4和2.0 mg/kg丙酸铬(CrPro)、吡啶甲酸铬(CrPic)和三氯化铬(CrCl₃)的试验饲粮。试验期21 d。结果表明:1)与对照组相比,试验组显著提高了热应激肉仔鸡的平均日增重(P<0.05),但铬源、铬水平及二者互作对热应激肉仔鸡平均日采食量和料重比无显著影响(P>0.05)。2)与对照组相比,试验组显著提高了热应激肉仔鸡的屠体率(P<0.05);腹脂率受铬源的显著影响(P<0.05),其中CrPro降低腹脂效果最好,CrCl₃其次,CrPic效果最差;铬源、铬水平及二者互作对热应激肉仔鸡的活体重、屠体率、全净膛率、胸肌率和腿肌率无显著影响(P>0.05)。3)与对照组相比,试验组显著提高了热应激肉仔鸡胸肌肉色红度值(P<0.05);胸肌蒸煮损失率受铬源的显著影响(P<0.05);,其中CrPro与CrCl₃的蒸煮率损失低于CrPic铬源、铬水平以及二者的互作对热应激肉仔鸡胸肌剪切力、pH_15min、pH_24h和亮度值、黄度值无显著影响(P>0.05)。由此可见,饲粮添加铬可以改善热应激肉仔鸡的生长性能、胴体性能及肉品质,且CrPro和CrCl₃形式的铬的效果优于CrPic。

This experiment was conducted to investigate the effects of dietary different chromium (Cr) sources and levels on growth performance, carcass traits and meat quality of broilers aged from 1 to 3 weeks under heat stress. A total of 252 one-day-old female Cobb broilers were randomly allotted into 7 groups with 6 replicates per group and 6 broilers per replicate. Broilers in the control group were fed a basal corn-soybean meal diet containing 0.37 mg/kg Cr, and the others in experimental groups were fed the basal diet supplemented with 0.4 or 2.0 mg/kg Cr as either Cr propionate (CrPro), or Cr picolinate (CrPic), or Cr chloride (CrCl₃), respectively. The experiment lasted for 21 days. The results showed as follows: 1) Cr source, Cr level and interactions between Cr source and level had no effects on average daily feed intake and feed to intake ratio in broilers aged from 1 to 3 weeks under heat stress (P>0.05), however, the average daily gain in experimental groups was significantly increased compared with that in control group (P<0.05). 2) No differences were observed in the live body weight, dressing percentage, whole pure thorax percentage, breast muscles percentage and thigh muscle of broilers aged from 1 to 3 weeks under heat stress (P>0.05), however, the dressing percentage in experimental groups was significantly increased compared with that in control group (P<0.05). There were significant differences among Cr sources in the of abdominal fat percentage (P<0.05), and CrPro group did the best, followed by the CrCl₃, with the CrPic coming in last. 3) The a^* value in experimental groups was significantly increased compared with that in control group (P<0.05). There were significant differences among Cr sources in the cook loss (P<0.05). Cr source, Cr level and interactions between Cr source and level had no effects on the shear force, pH, L^* and b^* value of the breast muscle (P>0.05). It is concluded that Cr supplementation can improve the growth performance, carcass performance and meat quality of broilers under heat stress, and it is better to supplement Cr from CrPro and CrCl₃ than CrPic in the diet of broilers under heat stress.