日粮中不同棉籽水平对肉牛瘤胃机能及消化率的影响研究
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摘要
本文以3头平均体重600±100kg、装有永久性瘤胃瘘管的7岁西杂阉牛为研究对象，实验采用3×3拉丁方设计，研究日粮中不同棉籽水平对肉牛瘤胃机能及消化率的影响作用，为肉牛日粮中适宜的整粒棉籽添加水平提供参考。
整个试验期的日粮由粗料和混合精料组成，每日供给约8.7kg，粗料为干制稻草和整粒棉籽，混合精料由玉米和棉饼组成，均为定量供给。三种试验日粮分别表示为：[1]对照组(CT)：饲喂基础日粮；[2]中棉籽组(MC)：13％棉籽；[3]高棉籽组(HC)：25％棉籽。整个试验设计分3期，每期16d，其中预饲期为10d，正试期为6d。正试期间测定有关瘤胃发酵参数(pH、NH_3-N、VFA)、稻草和棉籽的降解率及日粮养分(DM、OM、CP、EE、ADF)的消化率。
研究结果如下：
1 不同棉籽水平对瘤胃pH值的影响
在一个饲喂周期内，CT、MC、HC三个处理组pH值的平均值分别为6.69、6.58、6.60。与处理CT相比，处理MC、HC在一个周期内的pH平均值略有降低(-0.11、-0.09)。各处理在同一个时间点的pH值变化不显著(P＞0.05)。但饲喂后2h的变化趋势不同，处理CT、MC均呈下降趋势(-0.10、-0.32)，而处理HC呈上升趋势(+0.07)。
2 不同棉籽水平对瘤胃NH_3-N浓度的影响
在一个饲喂周期内，处理CT、MC、HC的NH_3-N浓度平均值分别为6.72mmol／l、7.01 mmol／l、6.65 mmol／l，其中处理MC的NH_3-N浓度平均值最高；与处理CT相比，处理MC的NH_3-N浓度平均值上升0.29mmol／l，处理HC的NH_3-N浓度平均值下降0.07mmol／l。各处理在同一时间点的NH_3-N浓度差异不显著(P＞0.05)。
3 不同棉籽水平对瘤胃VFA浓度的影响
整个试验期内，处理CT、MC、HC的总VFA浓度的平均值分别为：97.59mmol／l、104.82mmol／1、101.00mmol／l；与处理CT相比，处理MC、HC的总VFA浓度分别
日粮中不同棉籽水平对肉牛瘤胃机能及消化率的影响研究
提高7.4%、3.5%，乙酸和丙酸浓度平均值也较处理CT有所提高，而丁酸浓度和乙
酸/丙酸值比处理CT低。三种日粮间的乙酸/丙酸的平均值存在着显著性差异(P<
0.05)，其平均值分别为4.49、4.35、4.05。
4不同棉籽水平对稻草和棉籽中养分瘤胃降解率的影响
随着在瘤胃内培养时间的延长，稻草中各养分的降解率呈上升趋势。全期试验内，
对稻草DM、OM、NDF、ADF的有效降解率EDP，在处理间均随日粮中棉籽水平的
升一高显著降低(P<0.05)。
在一个饲喂周期内，各处理间对应时间点对全棉籽DM、EE(24h除外)的降解率
差异均不显著(P>0.05)。
5不同棉籽水平对日粮养分消化率的影响
在整个饲喂周期内，除EE、ADF的消化率存在差异外，处理CT、MC、HC间
的DM、OM、CP全消化道消化率差异均不显著(P>0.05)。与处理CT相比，处理
MC、HC的DM消化率分别下降0.06%、3.88%;与处理CT相比，处理MC的OM
消化率上升0.69%，处理HC的消化率下降3.53%;各处理的CP消化率有随棉籽水
平提高而上升的趋势，与处理CT相比，处理MC、HC的CP消化率分别上升4.52%、
6.06%。处理CT、MC的EE消化率与处理HC间均无显著性差异，但处理CT和
MC间的EE消化率差异显著(P<0.05)。与处理CT相比，处理MC、HC的ADF
消化率分别提高14.24%、10.05%。
Three 7-year old Simmcntal crossbred beef cattle(600±100kg body weight) fitted with ruminal cannulas were used in a 3 X 3 Latin square design to investigate the effects of different levels of cottonseed in diets on rumen fermentation and digestibility of nutrients for beef cattle,and to make reference to optimum level of cottonseed in beef cattle diets.
The experimental diets consisted of forage and concentrate were fed 8.7kg per day.Forage consisted of dried straw and whole cottonseed and concentrate consisted of corn grain and cottonseed meal, were all fixed quantity.Three experimental diets contained [1]contral(CT):basal diet; [2]middle cottonseed(MC):13% cottonseed and [3]high cottonseed(HC):25% cottonseed.The experiment included 3 feeding periods of 16 days each,and each period comprised a 10-day adaptation and 6-day collection.In the period of data collection,parameters about ruminal fermentation(pH, NH3-N, VFA), degradability of straw and cottonseed, and digestibity of dietary nutrients (DM,OM, CP, EE, ADF) were determined.
The results showed that:
1) Effect of different levels of cottonseed on ruminal fluid pH:
During a feeding period,the mean pH of three treatments CT,MC,HC were 6.69, 6.58, 6.60,respectively.The mean pH of treatments MC,HC in a feeding period,decreased a little(-0.11,-0.09),compared with treatment CT.There were no differences among treatments in pH of the same time(P>0.05).But the changing trend after feeding 2h was different,treatment CT,MC declined(-0.10,-0.32),while treatment HC rose(+0.07).
2) Effect of different levels of cottonseed on ruminal NH3-N concentration: During a feeding period,the mean NHs-N of three treatments CT,MC,HC were 6.72
mmol/1,7.01 mmol/1,6.65 mmol/1 ,respectively,and that of MC was the highest.Compared with treatment CT,the mean NHs-N of treatment MC increased by 0.29 mmol/l,while treatment HC decreased by 0.07 mmol/1. There were no differences among treatments in
NH3-N of the same time(P>0.05).
3) Effect of different levels of cottonseed on ruminal VFA concentration:
During a experimental period, the mean total VFA of three treatments CT,MC,HC were 97.59 mmol/1, 104.82 mmol/1,101.00 mmol/l,and compared with CT the others increased by 7.4%,3.5%, respectively.The mean acetate concentration and propionate concentration of treatment MC,HC were higher than that of treatment CT too,while butyrate concentrate and the ratio of acetate to propionate concentrate were lower than it.There were significant differences among the mean values of A/P in three diets(P< 0.05),and the mean values were 4.49,4.35,4.05,respectively.
4) Effect of different levels of cottonseed on degradability of nutrients in rice straw and cottonseed:
With ruminal fermentation continuing the degradability of nutrients in rice straw rose gradually. During a experimental period, with cottonseed level rising ,EDP of DM, OM, NDF, ADF of rice straw in three treatments droped significantly (P<0.05).
During a experimental period, No differences were observed in the degradability of DM and EE(except 24h) of whole cottonseed at the same time among treatments(P > 0.05).
5) Effect of different levels of cottonseed on digestibility of nutrients in diets: Except the differences in the digestibilities of EE and ADF among CT,MC and HC,
no differences(P > 0.05)were observed in other nutrients during a whole feeding period.Compared with treatment CT, DM digestibility in treament MC,HC decreased by 0.06%,3.88%,respectively;OM digestibility of treament MC increased by 0.69%,and that of treatment HC decreased by 3.53%. There is a upward tendency in CP digestibility with the level of cottonseed increasing.Compared with treatment CT treatment MC,HC increased CP digestibility by 4.52%,6.06%,respectively. Differences in EE digestibility were not significant between treatment CT,MC and treatment HC,but it was significant (P <0.05)between treatment CT and MC. Compared with treatment CT treatment MC,HC increased ADF digestibility by 14.24%, 10.05%, respectively.
整个试验期的日粮由粗料和混合精料组成，每日供给约8.7kg，粗料为干制稻草和整粒棉籽，混合精料由玉米和棉饼组成，均为定量供给。三种试验日粮分别表示为：[1]对照组(CT)：饲喂基础日粮；[2]中棉籽组(MC)：13％棉籽；[3]高棉籽组(HC)：25％棉籽。整个试验设计分3期，每期16d，其中预饲期为10d，正试期为6d。正试期间测定有关瘤胃发酵参数(pH、NH_3-N、VFA)、稻草和棉籽的降解率及日粮养分(DM、OM、CP、EE、ADF)的消化率。
研究结果如下：
1 不同棉籽水平对瘤胃pH值的影响
在一个饲喂周期内，CT、MC、HC三个处理组pH值的平均值分别为6.69、6.58、6.60。与处理CT相比，处理MC、HC在一个周期内的pH平均值略有降低(-0.11、-0.09)。各处理在同一个时间点的pH值变化不显著(P＞0.05)。但饲喂后2h的变化趋势不同，处理CT、MC均呈下降趋势(-0.10、-0.32)，而处理HC呈上升趋势(+0.07)。
2 不同棉籽水平对瘤胃NH_3-N浓度的影响
在一个饲喂周期内，处理CT、MC、HC的NH_3-N浓度平均值分别为6.72mmol／l、7.01 mmol／l、6.65 mmol／l，其中处理MC的NH_3-N浓度平均值最高；与处理CT相比，处理MC的NH_3-N浓度平均值上升0.29mmol／l，处理HC的NH_3-N浓度平均值下降0.07mmol／l。各处理在同一时间点的NH_3-N浓度差异不显著(P＞0.05)。
3 不同棉籽水平对瘤胃VFA浓度的影响
整个试验期内，处理CT、MC、HC的总VFA浓度的平均值分别为：97.59mmol／l、104.82mmol／1、101.00mmol／l；与处理CT相比，处理MC、HC的总VFA浓度分别
日粮中不同棉籽水平对肉牛瘤胃机能及消化率的影响研究
提高7.4%、3.5%，乙酸和丙酸浓度平均值也较处理CT有所提高，而丁酸浓度和乙
酸/丙酸值比处理CT低。三种日粮间的乙酸/丙酸的平均值存在着显著性差异(P<
0.05)，其平均值分别为4.49、4.35、4.05。
4不同棉籽水平对稻草和棉籽中养分瘤胃降解率的影响
随着在瘤胃内培养时间的延长，稻草中各养分的降解率呈上升趋势。全期试验内，
对稻草DM、OM、NDF、ADF的有效降解率EDP，在处理间均随日粮中棉籽水平的
升一高显著降低(P<0.05)。
在一个饲喂周期内，各处理间对应时间点对全棉籽DM、EE(24h除外)的降解率
差异均不显著(P>0.05)。
5不同棉籽水平对日粮养分消化率的影响
在整个饲喂周期内，除EE、ADF的消化率存在差异外，处理CT、MC、HC间
的DM、OM、CP全消化道消化率差异均不显著(P>0.05)。与处理CT相比，处理
MC、HC的DM消化率分别下降0.06%、3.88%;与处理CT相比，处理MC的OM
消化率上升0.69%，处理HC的消化率下降3.53%;各处理的CP消化率有随棉籽水
平提高而上升的趋势，与处理CT相比，处理MC、HC的CP消化率分别上升4.52%、
6.06%。处理CT、MC的EE消化率与处理HC间均无显著性差异，但处理CT和
MC间的EE消化率差异显著(P<0.05)。与处理CT相比，处理MC、HC的ADF
消化率分别提高14.24%、10.05%。
Three 7-year old Simmcntal crossbred beef cattle(600±100kg body weight) fitted with ruminal cannulas were used in a 3 X 3 Latin square design to investigate the effects of different levels of cottonseed in diets on rumen fermentation and digestibility of nutrients for beef cattle,and to make reference to optimum level of cottonseed in beef cattle diets.
The experimental diets consisted of forage and concentrate were fed 8.7kg per day.Forage consisted of dried straw and whole cottonseed and concentrate consisted of corn grain and cottonseed meal, were all fixed quantity.Three experimental diets contained [1]contral(CT):basal diet; [2]middle cottonseed(MC):13% cottonseed and [3]high cottonseed(HC):25% cottonseed.The experiment included 3 feeding periods of 16 days each,and each period comprised a 10-day adaptation and 6-day collection.In the period of data collection,parameters about ruminal fermentation(pH, NH3-N, VFA), degradability of straw and cottonseed, and digestibity of dietary nutrients (DM,OM, CP, EE, ADF) were determined.
The results showed that:
1) Effect of different levels of cottonseed on ruminal fluid pH:
During a feeding period,the mean pH of three treatments CT,MC,HC were 6.69, 6.58, 6.60,respectively.The mean pH of treatments MC,HC in a feeding period,decreased a little(-0.11,-0.09),compared with treatment CT.There were no differences among treatments in pH of the same time(P>0.05).But the changing trend after feeding 2h was different,treatment CT,MC declined(-0.10,-0.32),while treatment HC rose(+0.07).
2) Effect of different levels of cottonseed on ruminal NH3-N concentration: During a feeding period,the mean NHs-N of three treatments CT,MC,HC were 6.72
mmol/1,7.01 mmol/1,6.65 mmol/1 ,respectively,and that of MC was the highest.Compared with treatment CT,the mean NHs-N of treatment MC increased by 0.29 mmol/l,while treatment HC decreased by 0.07 mmol/1. There were no differences among treatments in
NH3-N of the same time(P>0.05).
3) Effect of different levels of cottonseed on ruminal VFA concentration:
During a experimental period, the mean total VFA of three treatments CT,MC,HC were 97.59 mmol/1, 104.82 mmol/1,101.00 mmol/l,and compared with CT the others increased by 7.4%,3.5%, respectively.The mean acetate concentration and propionate concentration of treatment MC,HC were higher than that of treatment CT too,while butyrate concentrate and the ratio of acetate to propionate concentrate were lower than it.There were significant differences among the mean values of A/P in three diets(P< 0.05),and the mean values were 4.49,4.35,4.05,respectively.
4) Effect of different levels of cottonseed on degradability of nutrients in rice straw and cottonseed:
With ruminal fermentation continuing the degradability of nutrients in rice straw rose gradually. During a experimental period, with cottonseed level rising ,EDP of DM, OM, NDF, ADF of rice straw in three treatments droped significantly (P<0.05).
During a experimental period, No differences were observed in the degradability of DM and EE(except 24h) of whole cottonseed at the same time among treatments(P > 0.05).
5) Effect of different levels of cottonseed on digestibility of nutrients in diets: Except the differences in the digestibilities of EE and ADF among CT,MC and HC,
no differences(P > 0.05)were observed in other nutrients during a whole feeding period.Compared with treatment CT, DM digestibility in treament MC,HC decreased by 0.06%,3.88%,respectively;OM digestibility of treament MC increased by 0.69%,and that of treatment HC decreased by 3.53%. There is a upward tendency in CP digestibility with the level of cottonseed increasing.Compared with treatment CT treatment MC,HC increased CP digestibility by 4.52%,6.06%,respectively. Differences in EE digestibility were not significant between treatment CT,MC and treatment HC,but it was significant (P <0.05)between treatment CT and MC. Compared with treatment CT treatment MC,HC increased ADF digestibility by 14.24%, 10.05%, respectively.
引文
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