饲粮添加硝酸钙对湖羊瘤胃动态发酵和抗氧化能力的影响

Effects of adding calcium nitrate to the diet on dynamic fermentation of the rumen and antioxidant capacity of Hu sheep

为研究饲粮中添加硝酸钙对湖羊瘤胃动态发酵和血清抗氧化能力的影响,试验采用交叉试验设计,选择安装有永久瘤胃瘘管湖羊6只,随机分为2组,每组3只,每只一个重复。对照组饲喂基础饲粮,试验组饲喂添加3%硝酸钙的饲粮。试验分2期进行,每期15 d,其中过渡期10 d,正试期5 d。在正试期的前2天采用动态pH监测系统对湖羊瘤胃pH进行24 h动态监测。在正试期的后2 d采集食后0、1、3、5 h和7 h的瘤胃液和血清,用于瘤胃挥发性脂肪酸(VFA)和氨态氮浓度及血清抗氧化指标的测定。结果表明:硝酸钙组湖羊瘤胃液中乙酸/总酸的比例和氨态氮浓度显著升高(P<0.05);丙酸/总酸的比例显著降低(P<0.05);且处理与时间对湖羊瘤胃液乙酸/总酸、乙酸/丙酸和氨态氮浓度可产生显著的交互作用(P<0.05)。硝酸钙提高湖羊瘤胃pH且pH低于5.60和5.80的时间短于对照组湖羊(P>0.05)。此外,硝酸钙组湖羊血清中总抗氧化能力(T-AOC)显著降低(P<0.05),且血清谷胱甘肽过氧化物酶(GSH-Px)活力随采食时间延长而降低(P<0.05)。综上所述,饲粮添加硝酸钙使湖羊瘤胃发酵朝乙酸型转变,且与时间有显著交互作用,有助于维持湖羊瘤胃内环境稳定,但饲粮添加3%硝酸钙会显著降低湖羊的抗氧化能力。

This experiment mainly studied the effect of adding calcium nitrate in the diet on the dynamic fermentation of the rumen and the antioxidant capacity in Hu sheep.Using a crossover trial design,6 Hu sheep with permanent rumen fistula were selected,and they were randomly divided into 2 groups,with 3 animals in each group,and each one was a duplicate.The control group was fed basal diet,and the test group was fed diet supplemented with 3%calcium nitrate.The test was carried out in 2 phases,each of 15 days,of which the acclimation was 10 days and the trial was 5 days.During the first 2 days of the trial period,a dynamic pH monitoring system was used to monitor the rumen pH in Hu sheep for 24 hours.The rumen fluid and serum at 0,1,3,5 h and 7 h after eating were collected on the last 2 days of the trial period for the determination of ruminal volatile fatty acid(VFA),ammonia nitrogen concentration and serum antioxidant indexes.The results showed that supplementation dietary calcium nitrate significantly increased the ratio of acetic acid/total acid and the concentration of ammonia nitrogen in the rumen fluid of Hu sheep(P<0.05);significantly reduced the ratio of propionic acid/total acid(P<0.05).The concentration of acetic acid/total acid,acetic acid/propionic acid and ammonia nitrogen concentration in the rumen fluid of Hu sheep were impacted by a interaction between treatments and time(P<0.05).Supplementation dietary calcium nitrate increased the ruminal pH of Hu sheep and the time that the pH was lower than 5.60 and 5.80 was shorter than that of the Hu sheep in control group(P>0.05).In addition,calcium nitrate significantly reduced the total antioxidant capacity(T-AOC)in the serum of Hu sheep(P<0.05),and the activity of serum glutathione peroxidase(GSH-Px)decreased with the prolonged time(P<0.05).In summary,supplementation dietary calcium nitrate changed the Hu sheep’s rumen fermentation to the acetic acid type,and there was a significant interaction with time,which helped to maintain the stability of the ruminal environment.Addition of 3%calcium nitrate to the diet,however,significantly reduced the antioxidant capacity in Hu sheep.