Potential contribution of absorbed volatile fatty acids to whole-animal energy requirement in conscious swine1

Abstract

Chronic cannulas were placed in the hepatic portal vein, ileal vein, and carotid artery in seven crossbred growing gilts trained to consume once daily 1.2 kg of a 16% CP corn-soybean meal diet. Eleven days after surgery, each pig (37.4 kg BW) was placed in an open-circuit calorimeter and its cannulas were connected to a system for determining portal absorption of nutrients. The whole-animal heat production and net portal absorption of gut VFA were measured simultaneously for 12 h after the pig was fed 1.2 kg of feed. Plasma concentrations of VFA, including acetic, propionic, isobutyric, butyric, isovaleric, and valeric acids, in portal and arterial samples were determined by gas chromatography after a cleanup by ion-exchange chromatography. The net portal absorption of VFA was calculated by multiplying the porto-arterial plasma concentration difference of the VFA by portal vein plasma flow. Plasma flow was estimated by the indicator-dilution technique using p-aminohippuric acid as the indicator. The energy value of absorbed VFA was the sum of products of each individual VFA multiplied by its corresponding value of the heat of combustion. The mean hourly energy value of absorbed VFA during the 12-h postprandial period was .65 +/- .03 kcal.h-1.kg BW-1. The mean hourly whole-animal heat production was 2.70 +/- .04 kcal.h-1.kg BW-1. Thus, in our 37.4-kg pigs, which were trained to consume 1.2 kg of a 16% CP corn-soybean meal diet once daily, the gut VFA absorbed into the portal vein could contribute 23.8 +/- 1.1% to whole-animal heat production if all of the absorbed VFA were combusted to CO2.

Influence of the nature of carbohydrate intake on the absorption chronology of reducing sugars and volatile fatty acids in the pig

“…Leaving out one meal therefore depresses the basal VFA production rate (R6rat et al, 1987). However, this does not explain why the VFA absorption was poorer than in previous experiments performed after 24 h of fasting (R6rat et al, 1987;Yen et al, 1991 This divergence probably appeared because semi-synthetic diets were used in the present study, whereas R6rat et al (1987) (R6rat et al, 1984). These differences probably depend on how the diet affects the length of gastric emptying, on the hydrolysation speed of the molecules according to their complexity (starch vs maltose), and on the nature and amount of enzyme secretion (amylase vs maltase).…”

“…A VFA mixture appears along the various stages of the efferent intestinal blood and the concentrations are highest in the coecocolic blood (Barcroft et al, 1944). The VFA profile has been measured in the peripheral blood of pigs (McClymont, 1951 in the portal blood (Friend et al, 1964) and more recently in both the arterial and portal blood (R6rat et al, 1985;Topping et al, 1985;Yen et al, 1991 ). Significant amounts of these substances are used by the enterocytes for their own metabolic needs during transport (Ly, 1974;Imoto and Namioka, 1978a, b).…”

“…The production of VFA is followed by absorption, as indicated by their presence in the portal blood (Topping et al, 1985) and quantified by measuring portal-arterial concentration differences and blood flow in the portal vein (R6rat et al, 1985, 1987Yen et al, 1991 ).…”

In vitro digestion and fermentation characteristics of canola co-products simulate their digestion in the pig intestine

“…Microbial fermentation of undigested feed produces gases and volatile fatty acids (VFA) that contribute up to 25% of the energy need of pigs (Yen et al, 1991). Production of butyric acid has been associated with improved gut health (Macfarlane and Macfarlane, 2012).…”

A Development of DDS Based Chirp Signal Generator and X-Band Transmitter-Receiver for Small SAR Sensor

“…This highlights the capacity of the pig to use a large amount of carbohydrates by hind gut fermentation. However, the net efficiency of utilization of energy via fermentation is still low in pigs (Yen et al, 1991).…”