. 2018 Oct 15;97(1):302–314. doi: 10.1093/jas/sky399

Table 3.

Predicted production and absorption of VFA in the hindgut (in vivo–in vitro methodology) of pigs fed the control, flaxseed meal and oat hulls diets (n = 8)

Item	Diet¹			SEM	P
Item	Control	FM	OH	SEM	P
Hindgut VFA produced by in vitro fermentation methodology (mmol/kg DM incubated)²
Acetic	2438^c	4342^a	2787^b	79.9	<0.001
Propionic	954^c	1875^a	1438^b	84.1	<0.001
Butyric	202^c	795^a	416^b	15.4	0.034
Valeric	211^b	604^a	220^b	14.9	0.008
Predicted hindgut VFA production (mmol/kg DM intake) (in vivo–in vitro technique)³
Acetic	346^c	759^a	416^b	18.0	0.041
Butyric	29^b	142^a	61^b	16.1	0.025
Propionic	135^c	332^a	211^b	12.8	<0.001
Valeric	30^b	107^a	35^b	3.0	0.038
Predicted VFA absorbed from the hindgut (mmol/kg DM intake) (in vivo–in vitro technique)⁴
Acetic	340^c	751^a	414^b	14.7	0.004
Butyric	27^c	140^a	60^b	4.2	<0.001
Propionic	135^c	330^a	199^b	11.6	0.028
Valeric	29^b	105^a	32^b	2.9	0.013
Predicted apparent VFA absorption in the hindgut (%) (in vivo–in vitro technique)⁵
Acetic	97.7^b	98.4^a	96.9^c	0.23	<0.001
Butyric	89.8^c	97.1^a	92.9^b	0.94	0.012
Propionic	96.5^b	98.2^a	96.7^b	0.22	<0.001
Valeric	98.4^a	98.8^a	96.6^b	0.45	0.003

^a,b,cMean values within a row with unlike superscripts differ (P < 0.05). Mean values with their pooled standard errors (n = 8 per treatment).

¹FM = flaxseed meal-containing diet; OH = oat hulls-containing diet. The predicted production and absorption of VFA were determined according to Montoya et al. (2016).

²The hindgut production of VFA in pigs was determined after in vitro fermentation of freeze-dried ileal digesta with fecal inoculum for 36 h at 37 °C.

³The predicted hindgut production of VFA in pigs was estimated based on the VFA produced after in vitro incubation of ileal digesta with a fecal inoculum corrected for the ileal flow of DM.

⁴The quantity of VFA absorbed in the hindgut was obtained after adding the VFA entering (ileal concentrations) and produced (estimated based on in vitro incubation of ileal digesta) in the hindgut, and then subtracting the excreted VFA (fecal concentrations).

⁵The apparent absorption in the pig hindgut was calculated based on the ratio between the predicted amount of VFA absorbed from the hindgut and the sum of the VFA entering (ileal concentrations) and produced (predicted based on an in vitro assay) in the hindgut.