Temporal effects of ruminal propionic acid infusion on feeding behavior of Holstein cows in the postpartum period

Abstract

The objective of this study was to determine the temporal effects of intraruminal infusion of propionic acid at the initiation of meals on feeding behavior of cows in the postpartum period. Propionic acid derived from ruminal fermentation can reduce energy intake of dairy cows. The suppression of appetite by propionic acid is likely caused by a signal related to the hepatic oxidation of fuels. Greater propionate flux to the liver is expected to result in faster oxidation of acetyl coenzyme A, which can stimulate satiety and reduce feed intake. Therefore, the rate of propionate supply to the liver, within the timeframe of meals, might be an important limitation to feed intake. Our hypothesis was that faster rate of propionate infusion during meals would decrease meal size and feed intake by decreasing the time required to stimulate satiety within a meal. Six ruminally cannulated, multiparous Holstein cows in the postpartum period were used in a duplicated 3 × 3 Latin square design experiment balanced for carryover effects. Treatments included control (no infusion) or 1.25 mol of propionic acid infused over 5 min (FST) or 15 min (SLW) at each meal. Infusions were initiated at the conditioned meal at feeding (1200 h) and were triggered at each spontaneous meal for 22 h. Contrary to our hypothesis, SLW decreased meal size 29% (0.87 vs. 1.23 kg of dry matter) compared with FST, and FST decreased meal frequency 27% (8.5 vs. 11.2 per d) compared with SLW. Dry matter intake was similar between FST and SLW, but propionic acid decreased dry matter intake 46% compared with control. A potential explanation is that FST resulted in greater liver bypass of propionate compared with SLW, extending anaplerosis of the tricarboxylic acid cycle, hepatic oxidation of acetyl coenzyme A, and satiety over a longer time after meals.

Temporal effects of ruminal infusion of propionic acid on hepatic metabolism in cows in the postpartum period

“…Therefore, hepatic oxidation might have been slower for FST compared with SLW because acetyl CoA concentration was not reduced by FST during the time frame of meals. That would explain how FST allowed for greater meal size in our previous experiment (Maldini and Allen, 2018). Consistent with this, Piantoni et al (2015) showed a positive relationship between the extent of reduction in plasma NEFA concentration and DMI during the first 4 h after feeding for cows in the PP period and that the reduction in plasma NEFA concentration and the reduction in hepatic acetyl CoA concentration were linearly related.…”

“…In a previous experiment, we observed an increase in meal size and extended time between meals by FST, reducing meal frequency of cows in the PP period (Maldini and Allen, 2018), and we hypothesized that FST saturated the pathway for propionate metabolism resulting in a lower first-pass extraction by the liver compared with SLW. However, the results of this experiment do not support our hypothesis.…”

“…Feed ingredients were dried in a 55°C forced-air oven for 72 h and analyzed for DM concentration. Samples were ground with a Wiley mill (1-mm screen; Arthur H. Thomas, Philadelphia, PA) and analyzed for ash, NDF, CP, and starch as described by Maldini and Allen (2018).…”

“…In a previous experiment, we evaluated ruminal infusions of 1.25 mol of PA over 5 min (FST) and 15 min (SLW) at each meal (Maldini and Allen, 2018). We expected that FST would decrease meal size compared with SLW by stimulating hepatic oxidation and resulting in satiety sooner.…”

Identification of Rumen Microbial Genes Involved in Pathways Linked to Appetite, Growth, and Feed Conversion Efficiency in Cattle

“…The animals’ appetite, feeding behaviour, and gastrointestinal motility (among other traits) are thought to be regulated by several mechanisms, including a communication between the rumen microbiome and the brain, through the gut–liver–brain axis (vagus nerve). This communication has been proposed to be mediated by multiple mechanisms, such as insulin/glucagon homeostasis, oxidation of acetyl coenzyme A, and release of VFA by the rumen microbiota (like propionate, associated with hypophagic behavior in ruminants, or butyrate and acetate, associated with motility of the gastrointestinal tract in monogastric animals; Sakata and Tamate, 1979; Cherbut, 2003; Oba and Allen, 2003; Arora et al, 2011; Maldini and Allen, 2018). Given the predictability of performance traits using relative abundances of rumen microbial genes observed in the present research (particularly that of DFI) and the high impact of the rumen microbiome on feed intake regulation (as discussed in the literature), we hypothesize that rumen microbial genes are closely involved in the metabolic pathways that regulate feed intake.…”