Digestibility of nitrogen and amino acids in soybean meal with added soyhulls1,2

Abstract

This study was designed to quantify the effect of soyhulls on N and AA digestibilities of soybean meal for growing pigs. Soyhulls were incorporated into 17% CP diets containing 33.25% soybean meal (SBM) at 0, 3, 6, or 9% (as-fed basis) and fed to 35-kg barrows to determine their effect on apparent and true digestibility of DM, GE, N, and AA measured at the terminal ileum. Positive and negative control diets containing 1.05% lysine were formulated with 35% SBM and 27% soy protein concentrate (SPC), respectively. A low-protein, casein-based diet was used to estimate endogenous AA losses. Soyhulls were incorporated into experimental diets at the expense of cornstarch, and SBM levels were adjusted to accommodate the contribution of CP from soyhulls. Fourteen pigs were surgically fitted with simple T-cannula at the distal ileum and fed the seven semipurified cornstarch diets based on a replicated 7 x 7 Latin square design. Each period lasted 7 d, with diet acclimation from d 1 to 5 and ileal sample collection for 12 h on d 6 and 7. Feed was offered at a level of 90 g/kg BW(0.75) in two equal portions at 0800 and 2000. Apparent ileal digestibilities of DM and GE decreased approximately six percentage units with the addition of soyhulls (linear, P < 0.05), whereas N was not affected. Both apparent and true ileal digestibilities of arginine, histidine, lysine, phenylalanine, aspartic acid, serine, and tyrosine also exhibited a decrease (linear, P < 0.05) of up to five percentage units with the addition of soyhulls. True ileal lysine digestibility of SBM decreased from 90.3 to 87.7% with the addition of 9% soyhulls. The endogenous nutrient fraction measured at the distal ileum was rich in proline, glutamic acid, and glycine, with losses greater than 1,000 mg/kg of DMI for each AA, and contained minimal amounts of tryptophan, methionine, and cystine. The current data suggest that a 0.2% decrease in some true ileal indispensable AA digestibilities may result with each 1% increase in soyhull inclusion in semipurified diets containing SBM as the sole source of AA as fed to growing pigs.

Apparent and standardized ileal digestibilities of amino acids for pigs fed corn- and soybean meal-based diets at varying crude protein levels

“…The barrows were surgically fitted with a simple T-cannula to enable collection of ileal digesta according to the procedures described by Dilger et al (2004). All of the pigs were…”

Nutrient analysis, metabolizable energy, and digestible amino acids of soybean meals of different origins for broilers

“…This finding was as expected because the IND samples are not dehulled and subjected to maximum possible extraction of oil during processing. The presence of hulls not only increases the fiber and NSP contents, but also serves as a diluent of nutrients (Dilger et al, 2004).…”

The site of intestinal disappearance of DDLmethionine and methionine hydroxy analog differs in pigs1

“…Barrows were selected at 25 kg, and simple T-cannulas were placed at the distal duodenum and distal ileum using procedures adapted from Dilger et al (2004). Feed was withdrawn, and pigs were administered an intramuscular injection of procainè penicillin (1,363 units/kg of BW; Norbrook Laboratories Limited, Newry.…”

“…Diets high in fiber have been shown to decrease the apparent digestibility and retention of N and AA in swine and poultry (Lenis et al, 1996;Dilger et al, 2004). Absorption of DLM and HMTBA begin in the duodenum and stomach, respectively.…”