低蛋白日粮蛋氨酸水平对肉鸡氮代谢及肌肉生长相关基因表达的影响

发布时间：2018-05-16 16:54

本文选题：低蛋白日粮 + 蛋氨酸　；参考：《吉林大学》2015年硕士论文

【摘要】：随着饲料蛋白资源越来越紧缺，动物氮磷排泄对环境造成的污染越来越严重，动物营养学家开始将目光转向了低蛋白日粮技术。单纯的低蛋白日粮有降低氮排泄保护生态环境的作用，但是同时也会在一定程度上降低动物生产性能。因此本文旨在研究低蛋白日粮中添加不同量的DL-蛋氨酸（DLM）对肉鸡生长、屠宰、氮代谢和肌肉生长相关基因表达的影响。 300只肉鸡随机分为五个处理组（A组、B组、C组、D组、E组），每个处理组设置4个重复，每个重复15只肉鸡，饲养试验为8到42日龄。A组对照组为正常蛋白水平（生长期CP23%，育肥期CP21%）正常蛋氨酸水平（生长期0.575%，育肥期0.509%）；其他四个处理组为试验组，其粗蛋白水平比正常对照组低2（%生长期为CP21%，育肥期为CP19%），B组蛋氨酸水平比对照组低0.07%（生长期0.501%，育肥期为0.438%），C组蛋氨酸与对照组一致，D组和E组在C组的基础上分别添加0.1%和0.2%的蛋氨酸。饲养期间测定各周采食量，逐周测定各只肉鸡体重，计算料肉比；从第2周开始，每周进行屠宰试验，从各重复中选取1只接近该重复平均体重的肉鸡，，测定其胸肌重、腿肌重和肝脏重，计算胸肌率、腿肌率、精肉率和肝脏率，在第5周和第6周的屠宰试验时测定胸肌肉色、pH和嫩度。Real-time PCR法测定42日龄胸肌的MRFs、Pax3/7、MSTN、HSP25以及胸肌中和Caspase-3基因mRNA表达量变化。在15-21日龄及36-42日龄期间从各重复中选取1只接近该重复平均体重肉鸡，在代谢试验中单饲，进行氮代谢平衡试验。通过饲料指示剂标记物法测定氮的代谢率及排泄率。在42日龄时对屠宰的肉鸡采血，测定血清中的尿素氮、尿酸、总蛋白、白蛋白、球蛋白、谷丙转氨酶、谷草转氨酶、血钙和碱性磷酸酶。结果表明：低蛋白日粮不同蛋氨酸水平对42日龄肉鸡体重影响不显著（P0.05），B组、C组和D组显著降低了肉鸡整个饲养期采食量（P0.05）,低蛋白日粮组均有降低料肉比的趋势，但是未表现出差异（P0.05）；在第3周时，D组显著降低了腿肌重和腿肌率（P0.05），到第6周时，D组的腿肌重大大提升，显著高于其他各处理组（P0.05），D组显著降低了42日龄肉鸡肝重（P0.05）；各处理组在28日龄、35日龄、42日龄的肉质性状（pH、肉色、剪切力）无显著差异（P0.05）。 B组显著降低了生长期的氮的代谢率（P0.05），低蛋白日粮组均有降低氮排泄量的趋势，并未表现出显著差异（P0.05）。低蛋白日粮均可以降低42日龄肉鸡血清中尿酸和尿素氮的水平，其中B、C组显著降低了尿酸水平（P0.05），B、E组显著降低了尿酸氮的水平（P0.05）。低蛋白日粮B组显著上调了肉鸡胸肌中Caspase-3基因的表达（P0.05），C、D组下调了Myogenin基因的表达（P0.05）。综上，低蛋白日粮中添加适量的蛋氨酸使得日粮蛋氨酸水平生长期达到0.6%到0.7%之间，育肥期0.54%到0.64%之间有提高肉鸡生长性能，改善饲料利用率，促进肌肉生长并且降低肉鸡氮的排泄作用。低蛋白日粮中缺乏蛋氨酸会上调肉鸡胸肌中Caspase-3基因的表达，这可能是蛋氨酸调控肌肉生长的关键基因之一。
[Abstract]:With the increasing shortage of feed protein resources, the pollution of nitrogen and phosphorus excretion to the environment is becoming more and more serious. Animal nutritionists begin to turn their eyes to low protein diet technology. Simple low protein diet has the effect of reducing nitrogen and excretion to protect the ecological environment, but at the same time, it will also reduce animal production performance to a certain extent. The aim of this study was to investigate the effects of different amounts of DL- methionine (DLM) in low protein diets on growth, slaughter, nitrogen metabolism and muscle growth related gene expression in broilers.
300 broilers were randomly divided into five treatment groups (group A, group B, group C, group D, E group). Each treatment group was set up 4 repetitions, each repeated 15 broilers, and the control group was normal protein level (growth period CP23%, fattening period CP21%) normal methionine level (growth period 0.575%, fattening period 0.509%), and the other four treatment groups were tested. The level of crude protein was 2 lower than that of the normal control group (CP21%, CP19%), and the level of methionine in group B was 0.07% lower than that of the control group (0.501%, 0.438%), and the methionine in group C was the same as that in the control group. The D and E groups added 0.1% and 0.2% methionine on the basis of C group respectively.
During the feeding period, the weight of each broiler was measured and the ratio of meat to meat was measured week by week. From the second weeks, a slaughtering test was carried out every week. 1 chickens were selected from each repetition. The weight of the chest muscle, the weight of the leg muscle and the weight of the liver were measured. The chest muscle rate, the leg muscle rate, the meat rate and the liver rate were calculated, at fifth and sixth weeks. The breast muscle color, pH and tenderness.Real-time PCR method were used to determine the MRFs, Pax3/7, MSTN, HSP25, and the mRNA expression of the Caspase-3 gene in the chest muscles of 42 days of age.
During the period of 15-21 days and 36-42 days of age, 1 chickens were selected from the repeated average weight broilers. The metabolic rate and excretion rate of nitrogen were measured by a single feed in the metabolic test. The rate of nitrogen metabolism and excretion were measured by the feed indicator marker method. The blood of slaughtered broilers was collected at 42 days of age and the serum urea nitrogen, uric acid and total protein were measured. Albumin, globulin, glutamic pyruvic transaminase, aspartate aminotransferase, blood calcium and alkaline phosphatase.
The results showed that the different levels of methionine in low protein diet had no significant influence on the weight of 42 day old broilers (P0.05). Group B, C and D significantly reduced the feed intake (P0.05) in the whole feeding period of the broiler, and the low protein diet group had the tendency to reduce the ratio of meat and meat, but did not show the difference (P0.05). In the third week, the D group significantly reduced the leg muscle weight and legs. The muscle rate (P0.05) was significantly higher in group D than in other treatment groups (P0.05) at sixth weeks. The liver weight of 42 day old broilers was significantly reduced in group D (P0.05), and there was no significant difference in meat quality (pH, meat color, shear force) at 28 days of age, 35 days of age and 42 days of age (P0.05) in each treatment group.
The B group significantly reduced the nitrogen metabolism rate (P0.05) in the growth period, and the low protein diet group had the trend of reducing nitrogen excretion, and did not show significant difference (P0.05). Low protein diet could reduce the level of uric acid and urea nitrogen in serum of 42 day old broilers, and B, C group decreased the level of uric acid (P0.05), B, and E group significantly reduced uric acid nitrogen. The level (P0.05).
Low protein diet group B significantly increased the expression of Caspase-3 gene in broiler breast muscle (P0.05), and C and D group down regulated Myogenin gene expression (P0.05).
To sum up, adding a proper amount of methionine in low protein diet can increase the level of dietary methionine growth between 0.6% and 0.7%, and increase the growth performance of Broilers by 0.54% to 0.64% in the fattening period, improve the feed utilization, promote muscle growth and reduce the excretion of broiler nitrogen. The lack of methionine in low protein diet will increase the breast muscle of broilers. The expression of Caspase-3 gene may be one of the key genes regulating methionine production by methionine.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S831.5

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