Ruminal lipopolysaccharide concentration and inflammatory response during grain-induced subacute ruminal acidosis in dairy cows
Ruminal lipopolysaccharide concentration and inflammatory response during grain-induced subacute ruminal acidosis in dairy cows
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DOI：
10.3168/jds.s0022-0302(07)71569-2
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发表时间：
2007-02-01
影响因子：
3.5
通讯作者：
Plaizier, J. C.
中科院分区：
文献类型：
--
作者：
Gozho, G. N.;Krause, D. O.;Plaizier, J. C.
本试验研究了谷物诱导的泌乳奶牛亚急性瘤胃酸中毒（SARA）对瘤胃内游离脂多糖（LPS）和炎症指标的影响。将4头泌乳中期奶牛分为2组，每组2头，采用重复试验设计。在每个阶段，通过用由50%小麦和50%大麦制成的浓缩物替代其总混合日粮（干物质基础）的25%，在2只动物中诱导SARA，持续5天。另外2头奶牛作为对照，饲喂全混合日粮，其中44%的干物质是浓缩物。平均而言，诱导SARA不影响乳成分，将瘤胃pH低于5.6的持续时间从187分钟/天增加到309分钟/天，并将游离瘤胃LPS浓度从24，547内毒素单位（EU）/mL增加到128，825 EU/mL。平均乳脂产量和乳蛋白产量分别为0.66和1.00 kg/d。瘤胃pH值和乳脂数据表明，对照组奶牛也发生了瘤胃酸中毒，尽管这种疾病的形式比SARA奶牛温和。对照组和SARA奶牛的血清LPS浓度均低于测定的检测限< 0.01 EU/mL。诱导SARA使血清淀粉样蛋白A浓度从286.8 μ g/mL升高至498.8 μ g/mL，但不影响其他炎症标志物，包括触珠蛋白、纤维蛋白原、血清铜或白色血细胞。这些结果表明，谷物诱导的SARA在泌乳中期奶牛增加革兰氏阴性菌的溶解，并激活炎症反应。
The effects of grain-induced subacute ruminal acidosis ( SARA) in lactating dairy cows on free ruminal lipopolysaccharide ( LPS) and indicators of inflammation were determined. Four mid lactation dairy cows were divided into 2 groups of 2 cows and used in a repeated switchover design. During each period, SARA was induced in 2 animals for 5 subsequent days by replacing 25% of their total mixed ration ( dry matter basis) with a concentrate made of 50% wheat and 50% barley. The other 2 cows acted as controls and were fed a total mixed ration diet in which 44% of dry matter was concentrate. On average, inducing SARA did not affect milk composition, increased the duration of rumen pH below 5.6 from 187 to 309 min/d, and increased free ruminal LPS concentration from 24,547 endotoxin units ( EU)/mL to 128,825 EU/mL. Averaged across treatments, milk fat yield and milk protein yield were 0.66 and 1.00 kg/d, respectively. Rumen pH and milk fat data suggest that control cows also experienced ruminal acidosis, albeit a milder form of this disease than SARA cows. Serum LPS concentration in both control and SARA cows was less than the detection limit of < 0.01 EU/mL for the assay. Induction of SARA elevated serum amyloid A concentration from 286.8 to 498.8 mu g/mL, but did not affect other markers of inflammation including haptoglobin, fibrinogen, serum copper, or white blood cells. These results suggest that grain-induced SARA in mid lactation dairy cows increases the lysis of gram-negative bacteria and activates an inflammatory response.