Effects of various starch feeding regimens on responses of dairy cows to intramammary lipopolysaccharide infusion

Abstract

Endotoxin tolerance (ET) can develop in mammals that have been challenged repeatedly with sublethal amounts of lipopolysaccharide (LPS). Previous research has shown that subclinical ruminal acidosis can increase circulating concentrations of LPS. We investigated whether ET would develop in Holstein cows that were subjected to chronic subacute ruminal acidosis (SARA) or acute SARA followed by intramammary infusion of LPS. Twenty-four cows, both primiparous and multiparous, were assigned to 8 blocks of 3 cows. Cows within blocks were randomly assigned to 1 of 3 treatments: (1) control (diet DM was 24% starch and 35% NDF), (2) high starch (formulated to induce chronic milk fat depression with 29% starch and 32% NDF), and (3) acidosis (designed to cause acute bouts of milk fat depression by short-term feeding of a diet with 32% starch, some of which came from wheat grain, and 30% NDF). Cows on the control and high-starch treatments were fed their respective diets throughout the 24-d trial. The acidosis cows were fed the control diet during most of the experiment, except during two 2-d bouts (d 10 and 11 and 17 and 18 of the experiment) in which a high-starch diet was fed. Cows on the high-starch and acidosis treatments produced milk fat with an altered fatty acid profile indicative of SARA (e.g., increased concentrations of specific trans, and odd-, and branched-chain fatty acids), but only cows on the high-starch treatment had milk fat depression. Concentrations of serum amyloid A were elevated in cows on the acidosis treatment, but did not differ between control and high-starch cows. On d 20 of the experiment, all cows were given an intramammary infusion of 10 µg of LPS into 1 mammary quarter 3h after morning milking. Milk yield and DMI decreased the day of the infusion, but the response was not affected by dietary treatment. No systemic indicators of ET were observed among treatments, but evidence of an ET response at the local level of the mammary gland was observed. Cows fed the control diet had higher concentrations of serum amyloid A in milk 12 and 24h postinfusion than did cows fed the high-starch diet and higher concentrations than cows on the acidosis treatment at 12h postinfusion. Our data suggest cows that experienced varying degrees of SARA (based on altered milk fatty acid profile) and subsequent experimental endotoxin mastitis experienced a blunted inflammatory response at the level of the mammary gland, but not a systemic reduction in some inflammatory mediators.

Intramammary infusion of Escherichia coli lipopolysaccharide negatively affects feed intake, chewing, and clinical variables, but some effects are stronger in cows experiencing subacute rumen acidosis

“…Perkins et al (2002) observed a decrease in rumen contractions after intramammary LPS (E. coli O111:B4) infusion at a dosage of 100 μg. However, in agreement with our study Gott et al (2015) observed no changes in rumen motility in cows receiving 10 μg of E. coli (O111:B4), suggesting dose-dependent responses of this variable.…”

“…As shown as a clinical inflammatory sign, the LPS challenge induced a strong increase in SCC (Wellnitz et al, 2011;Vernay et al, 2012;Gott et al, 2015). Our findings revealed no difference in SCC between SARA-LPS and CON-LPS cows.…”

“…However, the stronger responsiveness in cows experiencing SARA compared with the control cows is a new finding that deserves further investigations. In a recent study, Gott et al (2015) subjected cows to different starch feeding regimen (control vs. high starch vs. acidosis diets) and intramammary infused 10 μg of LPS (E. coli O111:B4) after 20 d of feeding the different diets. Although an overall decline in DMI was observed, no difference in the response of the cows of the different feeding regimen was found.…”

Lipopolysaccharide derived from the digestive tract triggers an inflammatory response in the uterus of mid-lactating dairy cows during SARA

“…However, there is little literature revealing that SARA not only depends on pH, but also on the alteration in the microbial population that develops secondarily to the feed type [34]. As a matter of fact, low ruminal pH values led to the lysis of gram-negative bacteria which released LPS into the blood circulation [31, 35]. Consistent with previous studies in dairy cows and feedlot, our results presented higher concentrations of LPS in the peripheral plasma (860 EU/mL) and ruminal fluid (79040 EU/mL) of cows fed a high concentrate die trelative to the peripheral plasma of the LC group [14, 36].…”

Invited review: Inflammation during the transition to lactation: New adventures with an old flame

“…This response was associated with elevated plasma concentrations of acute-phase proteins, indicating that systemic inflammation occurred. Although this subacute ruminal acidosis induction model is more extreme than what most cows would experience on a dairy, the sudden shift from dry-cow diets to high-grain lactation diets could cause similar responses (Gott et al, 2015). Some recent evidence suggests that even relatively short-term feed withdrawal can induce an acute-phase response (Marques et al, 2012), possibly through disruption of gut barrier function (Pearce et al, 2013), which is particularly relevant given the erratic feeding behavior of periparturient cows.…”