Metabolism of propionate and 1,2-propanediol absorbed from the washed reticulorumen of lactating cows

Abstract

To investigate the metabolism of 1,2-propanediol (PPD) in lactating cows independently of normal rumen microbial metabolism, three ruminally cannulated lactating Holstein cows were subjected to three experimental infusion protocols under washed reticulo-ruminal conditions in a Latin square design. Reticulo-ruminal absorption rates were maintained for 420 min by continuous intraruminal infusion of VFA and PPD. With the control treatment, 1,246 +/- 39 mmol/ h of acetate and 213 +/- 5 mmol/h of butyrate were absorbed from the reticulorumen. With the propionate treatment, 1,148 +/- 39 mmo/h of acetate, 730 +/- 23 mmol/h of propionate and 196 +/- 5 mmol/h of butyrate were absorbed from the reticulorumen. With PPD treatment, 1,264 +/- 39 mmol/h of acetate, 220 +/- 5 mmol/h of butyrate and 721 +/- 17 mmol/h of PPD were absorbed from the reticulorumen. Glucose irreversible loss rate (ILR), as well as the relative enrichment of plasma lactate and alanine, were determined by primed continuous infusion of [U-13C]glucose in a jugular vein. Treatments did not affect (P > 0.10) the plasma concentrations of glucose (4.2 +/- 0.1 mmoVL), alanine (0.14 +/- 0.01 mmol/L), or insulin (80 +/- 25 pmol/L). The plasma concentration of lactate was higher (P < 0.05) with both propionate (0.84 +/- 5 mmol/L) and PPD treatment (0.81 +/- 5 mmol/ L) compared with the control treatment (0.29 +/- 0.5 mmol/L). The plasma concentration of pyruvate was higher (P < 0.05) with the propionate treatment (0.09 +/- 0.01 mmol/L) compared with the control treatment (0.03 +/- 0.01 mmol/L). The plasma concentration of 3-hydroxybutyrate was lower (P < 0.05) with the propionate treatment (0.15 +/- 0.03 mmol/L) compared with the control treatment (0.40 +/- 0.03). With the PPD treatment, the plasma concentrations of pyruvate and 3-hydroxybutyrate were in between the other treatments and tended (P < 0.10) to be different from both. The plasma concentration of PPD increased throughout the infusion period with the PPD treatment and reached a concentration of 4.9 +/- 0.6 mmol/L at 420 min. The ILR of glucose was not affected (P > 0.10) by treatments (441 +/- 35 mmol/h). The relative 13C enrichment of plasma lactate compared with that of glucose decreased (P < 0.05) with the PPD treatment compared with the control treatment (44 to 21 +/- 3%). It was concluded that PPD has a low rate of metabolism in cows without a normal functioning rumen, although about 10% of the absorbed PPD was metabolized into lactate.

Effects of feeding dry propylene glycol to early postpartum Holstein dairy cows on production and blood parameters

“…to an increase in blood propionate concentration from microbial degradation of PG in the rumen (Kristensen and Raun, 2007) and/or (ii) an increase in tissue affinity for BHBA induced by PG directly or via endogenous metabolites (Kristensen et al, 2002). Insulin is a potent antilipolytic factor which reduces lipolysis in adipose tissue, thereby, reducing the release of NEFA from adipocytes to the liver (West and Passey, 1967).…”

“…The major site for PG metabolism seems to be in the rumen by rumen microorganism rather than in the liver of cows (Kristensen et al, 2002). PG is metabolized in the rumen rapidly as it has been shown to disappear from the rumen within 4 h of its infusion (Clapperton and Czerkawski, 1972;Kristensen and Raun, 2007), whereas its intermediary metabolism in the lactating cow is relatively slow (Kristensen et al, 2002;Kristensen and Raun, 2007).…”

“…PG is metabolized in the rumen rapidly as it has been shown to disappear from the rumen within 4 h of its infusion (Clapperton and Czerkawski, 1972;Kristensen and Raun, 2007), whereas its intermediary metabolism in the lactating cow is relatively slow (Kristensen et al, 2002;Kristensen and Raun, 2007). Kristensen and Raun (2007) estimated that between 33% and 45% of PG infused into the rumen was metabolized to propanol and propionate within the rumen and 19% of the infused PG escaped rumen degradation and was taken up and oxidized to L-lactate in the liver.…”

A suplementação com propilenoglicol melhora o metabolismo energético em ovelhas gestantes

“…Nos horários de coletas das 0, 3 e 6 horas após a alimentação, a inclusão de propilenoglicol na água aumentou linearmente o nível de glicose sanguínea das ovelhas, tais resultados corroboram os encontrados por alguns autores (Kristensen et al, 2002;Nielsen & Ingvartsen, 2004) em que verificaram que a suplementação com propilenoglicol (PG) aumentou as concentrações plasmáticas de glicose. Trabalho conduzido por Santos et al (2012) verificou que apesar de não haver diferença estatística nas concentrações séricas de glicose entre os grupos suplementados com propilenoglicol, foi importante ressaltar os valores superiores de glicose sanguínea no grupo suplementado com propilenoglicol no momento que antecedeu o parto (70,78 mg dL -1 ), quando comparado ao grupo que recebeu cobalto associado a vitamina B12 (57,21 mg dL -1 ) e ao grupo controle (57,76 mg dL -1 ).…”

Impact of glucogenic additive in transition dairy cow diets of varying ruminal starch degradability on yield and composition of milk and reproductive parameters

“…PG, according to Kristensen et al (2002), is quickly absorbed from the rumen wall or partly transformed into propionate in the rumen before being absorbed and converted in the liver into glucose. Propionate is easily released from calcium propionate, absorbed into blood in the rumen wall and transported to the liver, where it is converted into glucose via gluconeogenesis (Van Soest, 1994).…”