| The aim of this study was to investigate the effect of creatine monohydrate (CMH) supplementation on growth performance, carcass characteristics and meat quality in Cherry Valley Duck and to provide some referenced information for the further research and reasonable utilization in livestock and poultry industry. The study included there parts and the general results were presented as follows:In the first part:An experiment was designed to study the effect of CMH on growth performance and carcass composition of meat ducks. The relevant indexes in serum and muscle samples were relevent determined to analyze the source of weight gain, which could be due to increased muscle protein retention or increased water retention in the muscles, and prove whether it will regulate the fatty redistribution and deposition by slaughter test. A total of 360 healthy 25-years-old cherry valley ducks were randomly divided into 4 groups, every group included 3 replications which contained 30 ducks each. Experimental treatments were consist of:â… )a control diet;â…¡)a control diet with 0.05%CMH for 15days;â…¢) a control diet with 0.4%CMH for 5days followed by a control diet with 0.05%CMH for the next 10 days;â…£) a control diet with 0.4%CMH for 15days. The official test was beginning at 27-years-old, lasted for 15 days, and slaughtered at 42-d-old day. The result showed that:CMH supplementation signifigently increased the percentage of leg muscle, the percentage of lean meat also present a rising trend, especially groupâ…¡andâ…¢was significant difference(P<0.05), compared to the control group. Nevertheless, independent of which dosing strategy is followed, there are no significant effect on final body weight, weight gains, feed intake and feed conversion ratio. Moreover, the protein moisture ratio of the breast muscle of groupâ…¡andâ…¢and the leg muscle of groupâ…¢andâ…£presented a rising trend with no significant difference, but the leg muscle of groupâ…¡was significantly decreased which compared with groupâ…¢andâ…£(P<0.05). No matter which dosing regimen, CMH supplementation all improved the total protein and creatinine level in serum,while the content of uric acid showed a downward trend and groupâ…¢andâ…£was significant difference which compared with that in the control group (P<0.05). In addition, compared with the normal group, the other presented no significant effect on GOT, GPT and GLU, however both enzymes for groupâ…¡andâ…¢were increased, which GOT for groupâ…¡,â…¢and GPT for groupâ…¢was significant difference(P<0.05), compared to the groupâ…£. No matter which dosing regimen, CMH supplementation all improved the serum TG level, which groupâ…¢significantly increased by 39.27%(P<0.05). Furthermore, compared with the normal group, the other of Intramuscular fat width presented a rising trend, which groupâ…¢andâ…£significantly increased by 16.22%,14.85% respectively; While there were the same trend in the percentage of abdomen fat and crude fat in breast and leg muscule for groupâ…¢andâ…£, but no significant difference(P<0.05).In the second part:The study was conducted to research on the postmortem pH and meat quality of meat ducks with various CMH supplementations.The pH45min,pH24h, water-holding capability(WHC), meat color, lactic acid and glycogen were determined to confirm that whether it would delayed the postmortem pH decline, leading to a increase meat quality. The experimental design was the same as above. The result showed that:No matter which dosing regimen, CMH supplementation all improved the pH45min,pH24h in breast and leg muscle, compared with the normal group, breast pH45min in groupâ…¢was significantly increased by 0.14 unit(P<0.05), and leg pH45min,pH24h was extremely significantly increased by 0.14 and 0.32 unit(P<0.01), while leg pH24h in groupâ…¡,â…£by 0.17 and 0.21unit, respectively (P<0.05). Besides, there was a decreasing tendency in the drip loss of breast and leg muscle with the three CMH supplementations, which leg drip loss in groupâ…¢decreased significantly by 34.60%(P<0.05). The breast and leg muscle glycogen contents with various CMH adding protocol were higher than that of the control, which except the leg muscle glycogen level in groupâ…¡, as for the lactic acid showed a downward trend, and the breast glycogen contents in groupâ…¢,â…£was significantly increased by 62.94%(P<0.05),63.48%(P<0.05), the breast and leg muscle lactic acid level in groupâ…£by 31.53%(P<0.05),35.41%(P<0.05). Compared to the normal group, the breast L* in groupâ…¡,â…¢was increased by 3.58%,0.70%, as for the a* decreased by 3.44%,5.25% epectively, however in groupâ…£L*decreased by 2.38%, a* increased by 6.96%, and there was significant differenced between L* in groupâ…£andâ…¡(P<0.05), a* in groupâ…¡,â…¢andâ…£(P<0.05). Besides, the leg L* in groupâ…¡,â…¢,â…£decreased by 1.03%,3.58%(P<0.01),0.71% repectively, which compared with the other groups, groupâ…¢was extremely significantly differenced (P<0.01), the rest were no significantly effect.In the third part:The experiment was designed to study on the efficiency of creatine absorption with various CMH supplementation regimens:the contents of creatine, phosphocreatine, total creatine pool in breast and leg muscle and the former in serum, were determined by reversed-phase high performance liquid chromatography. The experimental design was the same as above. The result showed that:1. The blood creatine level improved by 25.14%,9.39% and 33.64%(P<0.05), respectively in groupâ…¡,â…¢,â…£with different CMH supplementation, which the difference of groupâ…£was significant. In CMH adding group, the contents of creatine, phosphocreatine and the total creatine pool in breast and leg muscle were all higher than that of the control, which the creatine level in breast muscle of groupâ…¡,â…¢were highly improved by 6.56%(P<0.05),5.84%(P<0.05), the creatine and total creatine pool contents in leg muscle of groupâ…¢,were all very significantly increased by 20.71%(P<0.01),22.05%(P<0.01), as well as the groupâ…£by 22.90%(P<0.01),22.89% (P<0.01), except the creatine and phosphocreatine level in leg muscle for groupâ…¡was lower,According to the above results, CMH supplementation had no significant effect on the growth performance of meat duck, however improved the rate of leg muscle and lean and regulated the intramuscular fatty deposition; otherwise it delayed the postmortem pH decline, and had a raising trend of water-holding capability. As a consequence Valley Duck was classified as a responder or quasiresponders to CMH supplementation, and the adding protocol of groupâ…¢was better than others. |
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