Acute Experimental Mastitis Is Not Causal Toward the Development of Energy-Related Metabolic Disorders in Early Postpartum Dairy Cows

Abstract

Twenty Holstein cows in early lactation (7 d in milk) were administered 100 microg of Escherichia coli lipopolysaccharide (LPS) dissolved in 10 mL of sterile 0.9% NaCl saline (treatment; TRT) or 10 mL of sterile saline (control) into both right mammary quarters to test the hypothesis that acute experimental mastitis would have negative impacts on aspects of energy metabolism that might lead to the development of metabolic disorders. A primed continuous intravenous infusion (14-micromol/kg of BW priming dose; 11.5-micromol/kg of BW per h continuous infusion) of 6,6-dideuterated glucose was used to determine pre- and posttreatment glucose kinetics using steady-state tracer methodologies. The LPS-treated cows displayed productive, clinical, and physiological signs of moderate to severe inflammation; control cows displayed no signs of immune activation. Pretreatment glucose rates of appearance (Ra) into plasma were similar (715 and 662 +/- 33 mmol/h for TRT and control, respectively) between treatment groups. Intramammary LPS infusion into TRT cows resulted in increased glucose Ra relative to control cows (mean glucose Ra from 150 through 270 min after intramammary infusion were 815 and 674 +/- 21 mmol/h for TRT and control cows, respectively). Furthermore, plasma concentrations of glucose increased, whereas plasma nonesterified fatty acids, glycerol, and beta-hydroxybutyrate concentrations decreased, in TRT relative to control cows. Interestingly, plasma insulin concentration increased dramatically in TRT cows and occurred prior to the small increase in plasma glucose concentration. Although these results only represent the early stages of inflammation, they are not consistent with a causal relationship between mastitis and energy-related metabolic disorders and instead suggest a coordinated protective effect by the immune system on metabolism during the early stages of mammary insult.

Hyperketonemia during lipopolysaccharide-induced mastitis affects systemic and local intramammary metabolism in dairy cows

“…An increased plasma insulin concentration in response to the LPS challenge in the present study is in agreement with previous studies (Waldron et al, 2003(Waldron et al, , 2006Vernay et al, 2012). Despite the inhibitory effect of insulin on glucagon secretion (Weir et al, 1976), plasma glucagon concentration increased after LPS challenge.…”

“…Intramammary LPS challenge did not affect plasma NEFA concentration in the present study. This finding is in agreement with a previous study that showed that intramammary LPS challenge did not affect plasma NEFA concentration, whereas plasma NEFA concentration increased in control cows that received NaCl (Waldron et al, 2006). The results of the present study are in contrast with a previous study where different doses of LPS were administrated intravenously for 100 min in mid-lactation dairy cows and plasma NEFA tended to increase after LPS challenge (Waldron et al, 2003).…”

“…As previously observed in response to intramammary LPS administration (Lehtolainen et al, 2003;Waldron et al, 2006;Vernay et al, 2012), plasma cortisol concentration increased in both treatment groups. Proinflammatory cytokines and possibly also the handling of the animals during the experiments likely activated the hypothalamus-pituitary-gland axis and increased the synthesis of glucocorticoids (Beishuizen and Thijs, (Andrews and Walker, 1999) to provide more glucose for the immune reaction.…”

“…The effect of the intramammary LPS challenge on FASN, OXCT1, and BDH2 mRNA abundance in quarters stimulated with LPS in both groups, and decrease in CS mRNA abundance in the control group showed that LPS challenge negatively affects mammary gland metabolism and milk synthesis, which had been reported before (Waldron et al, 2003(Waldron et al, , 2006. The increase in CS mRNA abundance in the HyperB group after LPS challenge is in agreement with Bionaz and Loor (2008), who suggested that the major product of BHBA metabolism in the bovine mammary gland is citrate, which is increased in milk.…”

“…Evidence exists that LPS challenge affects metabolism and mRNA abundance of inflammatory and other factors (Bruckmaier et al, 1993;Waldron et al, 2006;Vernay et al, 2012). In addition, it causes a decline of milk production (Bannerman et al, 2003).…”