本试验旨在研究肉鸡基础饲粮中添加一水肌酸(CMH)对骨骼肌肌酸的主动吸收和生化代谢的影响.选取42日龄的健康雄性岭南黄羽肉鸡900只,随机分成体重[(0.73±0.01) kg]接近的4个组(每个组5个重复,每个重复45只鸡):对照组饲喂未添加CMH的基础饲粮,试验组分别饲喂在基础饲粮中添加250、500和1 000 mg/kg CMH的试验饲粮,试验期21 d.结果表明:1)与对照组相比,添加500和1 000 mg/kg CMH显著上调了胸肌肌酸转运载体(CrT)的mRNA表达量(P＜0.05),而添加250 mg/kg CMH并未达到显著水平(P＞0.05)；添加不同水平的CMH对腿肌CrT mRNA表达量没有显著影响(P＞0.05).2)与对照组相比,添加250 mg/kg CMH显著降低了血清肌酸含量(P＜0.05),添加500和1 000 mg/kg CMH则与之相反(P＜0.05)；添加不同水平的CMH对血清肌酐含量和肌酐/肌酸没有显著影响(P＞0.05)；添加不同水平的CMH均极显著提高胸肌肌酸含量(P＜0.01),但对腿肌肌酸含量没有显著影响(P＞0.05)；随着CMH添加水平的增加,胸肌和腿肌的肌酐含量呈现剂量依赖性上升；添加不同水平的CMH均显著降低了胸肌肌酐/肌酸(P＜0.05),但腿肌的肌酐/肌酸随着CMH添加水平的增加而提高.3)与对照组相比,添加不同水平的CMH对腿肌肌酸激酶活性没有显著影响(P＞0.05)；但可显著提高胸肌肌酸激酶活性(P＜0.05).4)与对照组相比,添加不同水平的CMH对胸肌三磷酸腺苷(ATP)、二磷酸腺苷(ADP)、一磷酸腺苷(AMP)、总磷酸腺苷(TAN)含量和能荷值(EC)、ATP/ADP均没有显著影响(P＞0.05),但显著或极显著降低了AMP/ATP(P＜0.05或P＜0.01)；对腿肌ADP含量和EC、ATP/ADP、AMP/ATP的影响未达显著水平(P＞0.05)；添加250 mg/kg CMH显著提高腿肌ATP、AMP和TAN含量(P＜0.05).由此可见,添加250、500和1 000 mg/kg CMH可不同程度地促进骨骼肌对肌酸的吸收,同时增加胸肌肌酸和磷酸肌酸的储备,较好地增强肌酸代谢池的能量缓冲作用,并以添加低水平(250 mg/kg) CMH的效果更为显著.%This study was conducted to evaluate the effects of creatine monhydrate (CMH) on creatine uptake and its biochemical metabolism in skeletal muscle of broilers. A total of nine hundred 42-day-old healthy Ling-nan yellow-feathered broilers [ initial body weight = (0. 73 ± 0. 01) kg; male ] were randomly allotted to four groups with five replicates per group. The control group were fed a basal diet without CMH, and the experimental groups were fed the basal diets supplemented with 250, 500 and 1 000 mg/kg CMH, respectively. The experiment lasted for 21 days. The results showed as follows; 1) the supplementation of 500 and 1 000 mg/kg CMH significantly up-regulated creatine transporter (CrT) mRNA expression in breast muscle compared with the control group (P < 0. 05), but no significant change was observed in the group supplemented with 250 mg/kg CMH (P>0. 05). Different CMH supplemental levels did not affect CrT mRNA expression in thigh muscle (P >0. 05). 2) Compared with the control group, feeding the diet with250 mg/kg CMH significantly decreased serum creatine content (P <0. 05) , which was contrary to the other two groups with CMH supplementation (P <0.05). CMH supplementation did not affect serum creatinine content and creatinine/cre-atine, as well as creatine content in thigh muscle (P >0. 05) , but significantly increased creatine content in breast muscle (P <0.01). Creatinine content in breast muscle and thigh muscle was augmented as the increase of CMH level. Furthermore, creatinine/creatine in breast muscle was significantly decreased (P <0.05), but that in thigh muscle was improved in response to increasing CMH level (P <0. 05). 3) Compared with the control group, the supplementation of CMH can significantly increase the activity of creatine kinase in breast muscle (P < 0. 05) , but did not affect that in thigh muscle (P > 0.05). 4) Compared with the control group, the supplementation of CMH did not affect ATP, ADP, AMP and total adenine nucleotides (TAN) contents, energy charge (EC), and ATP/ADP in breast muscle (P >0.05). and the same results showed in these indexes of ADP content, EC, ATP/ADP and AMP/ATP in thigh muscle, too (P > 0. 05). However, 250, 500, and 1 000 mg/kg CMH supplemented in diets significantly decreased the AMP/ATP in breast muscle (P < 0.05 or P <0. 01), and 250 mg/kg CMH supplemental improved ATP, AMP and TAN content in thigh muscle (P < 0. 05). The results suggest that the supplementation of 250, 500 and 1 000 mg/kg CMH are be-nificial to improve creatine uptake in skeletal muscle, as well as the storage of creatine and phosphocreatine in breast muscle. Those indicate that some CHM added in diets for broilers can promote the energy buffering ability of creatine pool, especially the appropriate level of 250 mg/kg CMH.
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