日粮尿素添加水平对秦川肉牛瘤胃发酵性能及血液生化指标的影响

发布时间：2019-01-21 20:28

【摘要】：为研究秦川牛肉用新品系(以下简称“秦川肉牛”)日粮中添加尿素(非蛋白氮)对瘤胃发酵性能及血液生化指标的影响,选用3头装有瘤胃瘘管的成年秦川肉牛公牛,在日粮基本一致的条件下预饲25 d,试验共分5个处理阶段,每个处理阶段30 d,其中试验处理25 d,中间间隔5d作为缓冲期;5个试验处理阶段试验牛日粮添加尿素的比例分别为0%(干物质百分比,对照组)、0.5%(A组)、1.0%(B组)、1.5%(C组)和2.0%(D组),每个试验处理阶段每5 d采集一次瘤胃液,每个试验处理阶段最后1 d采集血样,对瘤胃液pH值、氨态氮(NH3-N)、微生物蛋白(MCP)、挥发性脂肪酸(VFA)、纤维素水解酶活性等5项瘤胃发酵参数,以及血清总蛋白(TP)、尿素氮(BUN)、谷丙转氨酶(ALT)、谷草转氨酶(AST)等4项血液生化指标进行了测定分析。主要研究结果如下:一、不同尿素添加水平对秦川肉牛瘤胃发酵性能的影响:随着尿素添加水平的提高,试验牛瘤胃液pH值呈现先下降后上升趋势,各处理组间差异显著(P0.05),其中B组(1.0%)pH值最低,为6.363±0.017;4个处理组的氨态氮(NH3-N)含量均显著高于对照组(P0.05),其中D组(2.0%)最高,为16.91±0.77 mg/dL;微生物蛋白(MCP)含量除D组(2.0%)与对照组差异不显著(P0.05)外,其余3个处理组均高于对照组,其中B组(1.0%)最高,为1.712±0.024 mg/mL,且与其它处理组差异显著(P0.05);除D组(2.0%)外,其他处理组总挥发性脂肪酸(VFA)含量均显著高于对照组(P0.05),B组(1.0%)最高,为149.59±3.79 mmol/L,且与其它处理组差异显著(P0.05);A组(0.5%)和B组(1.0%)挥发性脂肪酸(VFA)的几项指标与对照组均差异显著(P0.05),且这两处理组之间,除总挥发性脂肪酸(TVFA)差异显著外(P0.05),其余4项挥发性脂肪酸指标均差异不显著(P0.05);3种纤维素酶活性变化趋势基本一致,A组(0.5%)和B组(1.0%)3种纤维素酶活性均显著高于对照组与其他处理组(P0.05);各处理阶段的第5、10、15、20、25d瘤胃液各项发酵参数均差异不显著(P0.05)。二、不同尿素添加水平对秦川肉牛血液生化指标的影响:随着尿素添加水平的提高,试验牛血液生化指标(血清总蛋白(TP)、尿素氮(BUN)、谷丙转氨酶(ALP)和谷草转氨酶(AST))等4项指标均在正常值范围内波动;其中,试验各处理组谷丙转氨酶(ALP)水平差异不显著(P0.05);试验各处理组尿素氮(BUN)指标均高于对照组,其中,D组最高,且与对照组以及其他处理组差异显著(P0.05)。综上,日粮中添加尿素可以有效提高秦川肉牛瘤胃氨态氮(NH3-N)、微生物蛋白(MCP)、乙酸(C2)、丙酸(C3)以及纤维素水解酶活性等,且试验牛血液生化指标(血清总蛋白(TP)、尿素氮(BUN)、谷丙转氨酶(ALP)和谷草转氨酶(AST))均在正常值范围内波动。因此,本研究认为,在一般饲养条件下,日粮中尿素添加量2%(干物质百分比)是安全的,其中1%的添加量为最适安全添加量。
[Abstract]:In order to study the effects of urea (non-protein nitrogen) supplementation on rumen fermentation performance and blood biochemical indexes in a new line of Qinchuan beef ("Qinchuan Beef cattle"), three adult Qinchuan beef bulls with rumen fistula were selected. Under the condition of the same diet for 25 days, the experiment was divided into five treatment stages, each treatment stage was 30 days, of which the experimental treatment was 25 days, the intermediate interval was 5 days as the buffer period; The proportion of urea supplementation in diets of five trial stages was 0% (percentage of dry matter, control group), 0.5% (group A), 1.0% (group B), 1.5% (group C) and 2.0% (group D). Rumen fluid was collected every 5 days in each trial stage, and blood samples were collected on the last day of each trial stage. The pH value of rumen fluid, ammonia nitrogen (NH3-N) and volatile fatty acid (VFA), of microbial protein (MCP), were measured. Five parameters of rumen fermentation such as cellulose hydrolase activity and four blood biochemical indexes such as serum total protein (TP), urea nitrogen (BUN), alanine aminotransferase (ALT), alanine aminotransferase (AST) were determined and analyzed. The main results are as follows: first, the effect of different urea levels on rumen fermentation performance of Qinchuan beef cattle: with the increase of urea level, the pH value of rumen fluid decreased first and then increased. There was significant difference among the treatment groups (P0.05), and the pH value of group B (1.0%) was the lowest (6.363 卤0.017). The content of ammonia nitrogen (NH3-N) in the four treatment groups was significantly higher than that in the control group (P0.05). Group D (2.0%) was the highest (16.91 卤0.77 mg/dL;). The (MCP) content of microbial protein in group D (2.0%) was higher than that in control group (P 0.05), except that in group D (2.0%), the content of (MCP) in group B (1.0%) was the highest (1.712 卤0.024 mg/mL,). There was significant difference between the two groups (P0.05). Except group D (2.0%), the (VFA) content of total volatile fatty acids in treatment group was significantly higher than that in control group (P0.05), B (1.0%), 149.59 卤3.79 mmol/L,). There was significant difference between the two groups (P0.05). The indexes of volatile fatty acid (VFA) in group A (0.5%) and group B (1.0%) were significantly different from those in control group (P0.05). The other four indexes of volatile fatty acids were not significantly different (P0.05). The changes of the three cellulase activities were basically the same. The cellulase activities of group A (0.5%) and group B (1.0%) were significantly higher than those of the control group and other treatment groups (P0.05). There was no significant difference in fermentation parameters of rumen fluid in each treatment stage (P0.05). Second, the effect of different urea supplementation levels on the blood biochemical indexes of Qinchuan beef cattle: with the increase of urea addition level, the blood biochemical indexes (serum total protein (TP), urea nitrogen (BUN),) were tested. The four indexes of glutamate-pyruvic transaminase (ALP) and alanine aminotransferase (AST) fluctuated in the normal range. Among them, there was no significant difference in the level of glutamate-pyruvic transaminase (ALP) in each treatment group (P0.05). The (BUN) index of urea nitrogen in each treatment group was higher than that in the control group, among which, group D was the highest, and the difference was significant compared with the control group and other treatment groups (P0.05). In conclusion, supplementation of urea in diet can effectively increase the activities of rumen ammonia nitrogen (NH3-N), microbial protein (MCP), acetic acid (C2), propionic acid (C3) and cellulose hydrolase in Qinchuan beef cattle. The biochemical indexes (serum total protein (TP), urea nitrogen (BUN), alanine aminotransferase (ALP) and glutamic oxaloacetic transaminase (AST) (AST) all fluctuated in the normal range. Therefore, under the general feeding conditions, it is safe to add 2% urea (dry matter percentage) to the diet, and 1% of the supplementation amount is the most suitable safe addition amount.
【学位授予单位】：西北农林科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：S823.5

【相似文献】