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The objective of this study was to evaluate whether repeated oronasal administration of LPS before parturition showed effects on metabolic and clinical responses in periparturient dairy cows. Hundred Holstein dairy cows were randomly allocated to two treatment groups (n = 50). Thirty cows out of 100 were randomly assigned for intensive sampling (n = 15) started at 28 d before the expected day of parturition. Cows received an oral and a nasal treatment of 2 mL and 1 mL of sterile saline solution (0.15 M of NaCl), respectively, alone (control), or containing 3 increasing doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25, and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Blood samples were collected from coccygeal vein at different time points around parturition and analyzed for glucose, lactate, non-esterified fatty acids (NEFA), cholesterol, and betahydro-xybutyrate (BHBA). Clinical monitoring of animals was done throughout the experiment at different time points for overall health status, udder edema (UE), manure score, and body condition score (BCS). Results showed that oronasal administration of LPS increased concentrations of glucose and cholesterol in the serum compared to the control group (P < 0.05). The administration of LPS had no effect on concentrations of NEFA, BHBA, and lactate in the serum (P > 0.05). Oronasal LPS did not influence BCS, manure score or the incidence of UE (P > 0.05). Overall, repeated oronasal administration of LPS modulated some serum metabolites related to energy metabolism around parturition in the treated cows. Further research is warranted to elucidate the mechanisms behind greater glucose and cholesterol status in the serum and their potential effects on long-term metabolic health status of dairy cows.
high prevalence of sepsis in intensive care units and emergency rooms, along
with the high lethality of the sepsis cases makes the study of pathophysiology
of sepsis critically important. As a preclinical model, endotoxemia is an
important tool to study the pathophysiology of sepsis and septic shock. In
this review, we discussed aspects of endotoxemia as an experimental model in
sepsis research, including different techniques associated with the
purification of the endotoxin of Escherichia coli, serotype dependency and
dosage dependency of the experimental results.
The aim of this study was to evaluate the effects of repeated oronasal administration of lipopolysaccharide (LPS) on milk composition and the overall productive performance of dairy cows. One hundred pregnant Holstein dairy cows were randomly assigned to two treatment groups (n = 50). 30 cows out of 100 were selected for intensive sampling (n = 15) starting at 28 d before parturition. Cows were administered orally and nasally with 2 and 1 mL of saline solution, respectively (control), or saline solution containing 3 doses of LPS from Escherichia coli 0111:B4 as follows: 1) 0.01 μg/kg body weight (BW) on d ﹣28, 2) 0.05 μg/kg BW on d ﹣25 and ﹣21, and 3) 0.1 μg/kg BW on d ﹣18 and ﹣14. Daily feed intake and milk production were recorded for each cow during the first 28 d postpartum. Milk samples were obtained once per week and analyzed for various milk components. Overall, results indicated that treatment did not affect feed intake, milk yield, milk efficiency, fat content, fat yield, protein content, protein yield, lactose content, lactose yield, milk urea nitrogen (MUN), total solid contents, fat-corrected milk (FCM), and energy-corrected milk (ECM; P > 0.05). However, milk somatic cell count (SCC) tended to be lower in the treated cows (P < 0.10). Treated primiparous cows showed tendencies for better milk efficiency (P < 0.10), milk-fat content (P = 0.09), and total solid contents (P = 0.06). There was a treatment by week interaction for milk energy (P = 0.03), and tendencies for FCM, ECM, lactose content, and milk efficiency (P < 0.10) with greater values in the treated primiparous animals. Altogether, results of this study showed that oronasal LPS challenges slightly modulated milk composition of periparturient dairy cows.
Lon protease, an ATP-dependent protease in Escherichia coli, degrades
abnormal proteins and regulates several important cellular functions. Here we
show novel inhibitory effects of lipopolysaccharide (LPS) on Lon protease
activities. LPS inhibited the peptidase, protease, and ATPase activities of
Lon; and a dose-response study showed that LPS at low doses more effectively
inhibited the ATPase activity than the peptidase one, suggesting different
susceptibility to LPS of these activities associated with Lon. Structure-activity relationship studies revealed that
ReLPS, detoxified LPS, and mono-phosphoryl as well as diphosphoryl
lipid A, also showed similar inhibition, suggesting that neither O-antigen
polysaccharide nor O-acyl chain, but rather phosphate groups in the lipid A
domain, seem to have been responsible for the inhibitory effects. Besides,
LPS was co-precipitated with Lon by an anti-Lon antibody, showing the direct
binding of LPS to Lon. These results suggest that LPS bound to Lon and
inhibited the protease activity of Lon by inhibiting its ATPase activity. These
results also seem to be another example of a negatively charged phosphate
group in membrane components of Escherichia coli being involved in the
regulation of protease activity of Lon through binding to Lon and inhibiting
its ATPase activity, as in the case of cardiolipin.