Data have been published for the composition of wheat middlings from flour mills in the U.S. and data for digestible energy (DE) and metabolizable energy (ME) have been reported as well. However, it is not known if the data obtained in wheat middlings from the U.S. also are representative for wheat middlings in Europe. Therefore, an experiment was conducted to test the null hypothesis that there are no differences in composition, apparent total tract digestibility (ATTD) of gross energy (GE), and concentration of DE and ME between wheat middlings sourced from flour mills in Europe and in the U.S.

Experimental design

Ten sources of wheat middlings were used in the experiment. Five sources were procured from Europe (i.e., Germany, Spain, France, Hungary, and Italy) and the other five sources were procured from the U.S. (i.e., sources 01, 02, 03, 04, and 05). A basal diet based corn and soybean meal was formulated. Ten additional diets containing corn, soybean meal, and one of the ten sources of wheat middlings were also formulated. Eighty eight pigs (27.24 ± 2.54 kg) were used and allotted to 11 diets with eight replicate pigs per diet. Pigs were housed individually in metabolism crates. The initial 5 days were considered the adaptation period to diets, and fecal and urine samples were collected for 4 days following the adaptation period. Diets, ingredients, fecal, and urine samples were analyzed for gross energy to calculate for apparent total tract digestibility (ATTD) of gross energy (GE) and DE and ME in each diet. The DE and ME in wheat middlings sources were calculated by difference.

Results

The concentration of starch for the wheat middlings in Hungary is 7.9%, which was less compared with other European sources (Table 1). As a result, the variability of starch in wheat middlings from Europe was greater compared with sources from the U.S. Wheat middlings sourced from Germany and Hungary had the greatest concentration of total dietary fiber, whereas U.S. source 01 had the least concentration of total dietary fiber. The ATTD of GE and dry matter (DM) in wheat middlings sourced from Europe was less (P < 0.05) compared with that of wheat middlings sourced from U.S. (Table 2). Wheat middlings from Hungary had the least (P < 0.01) concentration of DE (as-fed basis and DM basis), whereas wheat middlings from Spain and U.S. source 1 had the greatest (P < 0.01) concentration of DE (as-fed basis and DM basis). Wheat middlings sourced from Europe had reduced (P < 0.05) concentrations of DE and ME (as-fed basis and DM basis) compared with wheat middlings sourced from U.S.

 

Key points

• The ATTD of GE and DM and concentration of DE in wheat middlings from Hungary were less than in other sources.
• Wheat middlings sourced from Europe had reduced concentrations of DE and ME compared with wheat middlings sourced from U.S., which is likely due to increased concentration of dietary fiber with a subsequent reduction of starch in wheat middlings from Europe compared with wheat middlings from U.S.
• The ATTD of GE and DE and ME values in ten sources of wheat middlings is possibly a result of differences among flour mills in the production process between the US and European countries.

Table 1. Analyzed composition of the ten sources of wheat middlings (as fed basis)

¹G = Germany; S = Spain; F = France; H = Hungary; I = Italy.

²AEE = acid-hydrolyzed ether extract; SDF = soluble dietary fiber; IDF = insoluble dietary fiber; TDF = total dietary fiber.

Table 2. Apparent total tract digestibility (%) of gross energy (GE) and dry matter (DM), and concentrations of digestible energy (DE) and metabolizable energy (ME) in ten sources of wheat middlings¹

¹Data are least squares means of 7 to 8 observations per treatment.

²G = Germany; S = Spain; F = France; H = Hungary; I = Italy.

³Comparison of the ten sources of wheat middlings.

^a-eMeans within a row lacking a common superscript differ (P < 0.05).