Nutrition, microbiota, and endotoxin-related diseases in dairy cows

Abstract

-In this review article we present an overall summary of the role that high-grain/low forage diets have on rumen composition of microbiota and how changes in the diet affect the release of bacterial cell wall components that are toxic to the host. One of these toxic compounds is lipopolysaccharide or endotoxin, a component of the outer membrane of all Gram-negative bacteria. Moreover, data are provided that support the concept that endotoxin translocates into the blood circulation and show that rumen endotoxin is associated with multiple perturbations of blood variables related to carbohydrate, lipid, and mineral metabolism. In addition, endotoxin induces a general, nonspecific immune response known as acute phase response. We also pinpoint the fact that high-grain diets are associated with distinct clusters of plasma metabolites and immune variables suggesting that changing cereal grain to forage ratio in the diet is very important for the health of dairy cattle. Furthermore, we provide information that support the concept that endotoxin is involved in multiple metabolic diseases such as fatty liver, milk fever, laminitis, retained placenta, displaced abomasum, and downer cow syndrome. More research is warranted to clarify the mechanisms by which nutrition, microbiota, and endotoxin contribute to development of metabolic diseases in dairy cattle. It is concluded that besides the aforementioned causal agents other compounds generated in the gastrointestinal tract such as lipoteichoic acid or methylated amines might be involved in the etiology of several metabolic diseases.Key Words: dairy cow, endotoxin, metabolic disorders, nutritional immunology Nutrição, microbiota e doenças relacionadas à endotoxina em vacas leiteiras RESUMO -Neste artigo de revisão é apresentado um resumo total do papel que a dieta de alto teor de grãos e baixo teor de forragem tem sobre a composição da microbiota do rúmen e como as mudanças na dieta afetam a liberação de componentes da parede celular bacteriana tóxicos ao hospedeiro. Um destes compostos tóxicos é um lipopolisacarídeo ou endotoxina, um componente da membrana exterior de todas bactérias gram-negativas. Também são fornecidos dados que apoiam a idéia de que a endotoxina se transloca na circulação sanguínea e que estas endotoxinas ruminais estão associadas a múltiplas perturbações das variáveis sanguíneas relacionadas a carboidratos, lipídios e metabolismo mineral. Além disso, endotoxina induz resposta imune geral e não específica, denominada resposta aguda de fase. Destaca-se também o fato de que dietas de alto teor de grão estão associadas a grupos distintos de metabolitos do plasma e variáveis imunes, sugerindo que a mudança na proporção entre grãos de cereal e forragem na dieta é muito importante para a saúde do gado leiteiro.Fornecemos também informações que apoiam o conceito de que a endotoxina está envolvida em múltiplas doenças metabólicas, como fígado gorduroso, febre do leite, laminitis, placenta retida, abomasum deslocado e síndrome downer cow.Maior número d...

Effect of <italic>Saccharomyces cerevisiae</italic> Fermentation Product on Lactation Performance and Lipopolysaccharide Concentration of Dairy Cows

“…Ametaj et al (2010) observed that a strong negative relationship between preprandial rumen pH and concentration of LPS in the rumen fluid. Thus, rumen pH modifiers could affect the endotoxin concentration.…”

Oral administration of LPS and lipoteichoic acid prepartum modulated reactants of innate and humoral immunity in periparturient dairy cows

“…3,4 Early postpartum, cows encounter various immunogenic substances, such as LPS and lipoteichoic acid (LTA), which are important components of the Gram-negative and Gram-positive bacterial cell wall, respectively. 5 Additional exposure of mucosal layers to LPS and LTA occurs owing to accumulation of cell-free LPS or LTA in the rumen when cows are switched from a roughage-rich to a grain-rich diet 6,7 at the onset of lactation. However, the virulence properties of those immunogenic compounds are highly influenced by the sudden switch in diet postpartum.…”

Application of Acute Phase Proteins for Monitoring Inflammatory States in Cattle

“…Recent data have suggested that blood LBP might be used as a biomarker for downer cow syndrome (DCS). An observational study by Ametaj et al (2010) showed a strong association between DCS and plasma LBP (a 10-fold increase) at 7 d before parturition. Moreover, results indicated that cows affected by DCS had lower anti-LPS IgG and greater concentrations of anti-LPS IgM.…”