Acid-insoluble ash is a better indigestible marker than chromic oxide to measure apparent total tract digestibility in pigs

Abstract

The aim of this study was to determine the apparent total tract digestibility (ATTD) of nutrients in cottonseed meal (CSM) and soybean meal (SBM) in simple carbohydrate and more complex wheat-based diets using 2 indigestible markers and total faecal collection. Twenty-five Large White × Landrace boars (57.8 kg) were randomly allocated to either a pure wheat diet, 40% CSM or SBM in either a sugar-starch- (1:1) or wheat-based diet for 18 d. Acid-insoluble ash (AIA) and chromic oxide (Cr 2 O 3 ) were included in all diets as indigestible markers. Diets were offered (1,800 g/d per pig) in 3 meals/d from d 1 to 11 and 8 meals/d from d 12 to 17. On d 9, the pigs were moved to individual metabolism cages to allow total faecal collection. On d 18, the pigs were fed hourly for 8 h. After the 8th meal, pigs were anaesthetized and digesta sampled from the terminal ileum and rectum before lethal injection. There were no differences between ATTD of nitrogen (N) determined using AIA as a marker and measured by total faecal collection. On the other hand, the ATTD of N of diets containing CSM in sugar-starch- or wheat-based diets and the pure wheat diet determined using Cr 2 O 3 as a marker was less (−3.11%, −4.46% and −6.59%; P < 0.001) than that measured by total faecal collection. The ATTD of N determined using AIA as a marker was highly correlated with that measured using total faecal collection ( P < 0.001; R 2 = 0.95). Similarly, the ATTD of N determined using Cr 2 O 3 as a marker was correlated with that measured using total faecal collection, although the correlation was not quite as strong as using AIA ( P < 0.001; R 2 = 0.87). Also, the slope of the regression line and the intercept were closer to unity and zero for the relationship when the ATTD of N was determined using AIA compared to Cr 2 O 3 as an indigestible marker. The ATTD of organic and dry matter behaved similarly. These data demonstrate that the basal diet and choice of indigestible marker can substantially influence the ATTD and that the use of AIA as an indigestible marker is more suitable than Cr 2 O 3 in digestibility studies in pigs.

Sweet vs. Salty Former Food Products in Post-Weaning Piglets: Effects on Growth, Apparent Total Tract Digestibility and Blood Metabolites

“…Regarding the chemical composition and nutritional values, the FFPs-C and FFPs-B diets are comparable with other studies [ 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. One of the main concerns about this material is its homogeneity and stability in composition over the time.…”

“…The ATTD of DM was determined using the acid-insoluble ashes (AIA) method [ 16 ]. Acid-insoluble ash (AIA) is considered a neutral marker for determining digestibility of feed in pigs and seems more suitable than metal elements like iron or chromium [ 17 ]. The amount of natural occurring AIA in the feed was verified in all experimental diets in order to avoid the inclusion metal elements as indigestible markers.…”

“…The amount of natural occurring AIA in the feed was verified in all experimental diets in order to avoid the inclusion metal elements as indigestible markers. The amount of natural occurring AIA was above 4 g·kg −1 feed in all experimental diets, which is considered more than adequate for the estimation of ATTD in pig [ 16 , 17 ]; accordingly, non-inclusion of supplemental AIA sources was performed. After being collected, the feces were stored in plastic containers and frozen at −20 °C until the time of analysis.…”

Porcine bile acids promote the utilization of fat and vitamin A under low-fat diets

“…Acid-insoluble ash (AIA) was used as an endogenous indicator to determine the total tract nutrients apparent utilization according to the method previously described ( 20 ). Crude fat (EE) was determined by Soxhlet extraction method according to AOAC (method 920.39).…”

“…A total of 5 g of soybean oil or corn oil was weighed and placed in conical flasks. Then, 300 mg of lipase, 25 mL of PBS, 0, 5,10,15,20,25,30,35,40, and 45 mg of BAs were added to the conical flasks, respectively. The pH of the solution was adjusted to 6.8 with hydrochloric acid, and then placed in a shaking water bath (180 rpm) to react at 40 • C for 3.5 h. After cooling to room temperature, we added 2∼3 drops of phenolphthalein indicator solution in the mixed solution and then titrated with the potassium hydroxide (KOH) standard titration solution (0.05 mol/L), until it appeared reddish and did not fade within 30 s as the end point.…”