Inflammatory Damage Mechanism Of Endogenous LPS On Rumen And Cecum Of Dairy Cows

In China,forages are in short supply,and the quality is low.High grain diets are widely used.Cows are fed high concentrate diets to meet the energy and nutrients demands,which is associated with a rapid decline in ruminal pH and causes subacute ruminal acidosis(SARA).At the same time,high concentrate diets can disturb the balance of microbial in rumen,result in the large amounts release of bacterial endotoxin(LPS) from gram negative bacteria in the rumen,then increase the concentrations of LPS in the rumen fluid and feces.High concentrations of LPS can translocate into the bloodstream through the digestive tract barriers,which increases LPS concentrations in the blood,causes the body systemic inflammation.It affects dairy cow performance and economic benefits in farm.In current state,forage ratio is generally high in our country’s dairy farming.I produced a study on LPS affects mechanism of inflammation in rumen and cecal.Experiment 1:Determination of rumen and cecal contents LPS content:most of our high-lactating dairy cattle ranch in order to maintain the state of the widespread use of high-concentrate diets mode, however, this model can easily produce subacute rumen acidosis, causing endogenous LPS is a lot of production. Under the experimental study of two major dietary patterns, high concentrate/low concentrate 6:4 and high concentrate/low concentrate 4:6 circumstances six cows were caused subacute ruminal acidosis, resulting in the rumen and cecal to produce endogenous of LPS, feeding six months after the slaughter of the cows were collected rumen fluid, cecal contents, the use of LAL box measuring rumen and cecal contents LPS content. The results showed that cecal contents were higher than in the LPS rumen contents; rumen juice concentrate high levels of LPS group than the low concentrate group, the difference was significant (P<0.05); high cecal contents LPS content concentrate group than the low concentrate group, the difference was significant (P<0.01).Experiment 2:Endogenous LPS has effect on histopathology of rumen papillae, rumen wall and cecal wall:To investigate the endogenous LPS effecting on histopathology of rumen papillae, rumen wall and cecal,the test selected six Holstein cows and they were randomly divided into 2 groups,all of cows were fed high concentrate/low concentrate 6:4 and high concentrate/low concentrate 4:6,meanwhile, six cows were fitted with permanent rumen fistula.Test stage were 6 months. Feeding trials collecting rumen papillae by rumen fistula, rumen papillae was made tissue section with HE staining.After the feeding trial, six cows were slaughtered.Collecting the rumen wall,cecal wall samples,and making tissue section with HE staining,observating different dietary forage ratio groups of cows rumen papillae, rumen wall and cecal wall. The results showed how many levels of endogenous LPS makes rumen papillae and rumen wall mucosa with varying degrees inflammatory injury, high levels of endogenous LPS test rumen papillae and rumen wall mucosa layer became more thinner and cuticle shedding. There were higher levels endogenous LPS in the cecum, so it could induce serious inflammatory injury,and destruct integrity of the cecum wall.The cecum epithelium and colon wall glandular also appeared damage.Experiment 3:Endogenous LPS has effects on rumen papillae, rumen wall, cecal wall related gene expression of inflammatory injury:In order to investigate the endogenous LPS that produced by different types of feed ration effecting on rumen papillae, rumen wall and cecal wall,6 Holstein cows were choiced and they were randomly divided into 2 groups of three, all of cows were fed high concentrate/low concentrate 6:4 and high concentrate/low concentrate 4:6, and six cows were fitted with permanent rumen fistula. A trial period of six months. collecting rumen papillae by rumen fistula, and then storing in -70℃ liquid nitrogen, After the feeding trial, six cows were slaughtered, Collecting the rumen wall and cecal wall samples, they were stored in -70℃ liquid nitrogen.Tests measured key factor’s gene relative expression levels in the inflammatory mechanism of injury TLR-4, LBP, NF-κB, IL-1, IL-6, IL-8, TNF-a with real-time PCR technology. Studying impact on the inflammatory injury related gene expression of rumen and cecal. The results showed that in concentrate group rumen papillae (in addition to IL-1, IL-6, IL-8), rumen wall and cecal wall inflammatory cytokines relative expression levels were higher than low concentrate group, in addition, the rumen wall of the relative IL-1 and IL-6 expression levels were differences between significantly,the cecum wall of the relative IL-1 expression levels were much differences significant.