Ileal true digestibility of amino acids in wheat milling by-products for pigs

Abstract

-Ten batches of wheat milling by-products -3 of wheat middlings (WM), 4 of wheat feed (WF), 3 of wheat bran (WB) -were analysed and studied for their protein and amino acid ileal true digestibility (ITD). Each batch was tested on four castrated male pigs weighing between 35 and 95 kg, and fitted with an end-to-end ileo-rectal anastomosis. In all types of by-products, lysine and threonine were among the least digestible amino acids, whereas methionine was among the most digestible ones. N and all amino acids ITD decreased significantly (P < 0.05) from WM to WF and to WB. In WM, the average N, lysine, threonine and methionine ITD values were 93.6, 90.8, 90.4 and 95.1%, respectively. They decreased to 85.5, 86.6, 83.3 and 91.5%, respectively in WF and down to 70.1, 68.3, 68.4 and 78.9%, respectively in WB. N and all amino acids ITD was predicted according to either the ratio of the feedstuff fibre to amino acid concentrations, or the proportion of total N bound to the NDF (neutral detergent fibre) residue, or both. For most amino acids, the use of CF (crude fibre), ADF (acid detergent fibre) or ADL (acid detergent lignin) as fibre criteria provided accurate equations with coefficient of determination higher than 90%. wheat milling by-products / ileal digestibility / amino acids / pigsRésumé -Digestibilité iléale des acides aminés des issues de meunerie chez le porc. L'objectif de ce travail était de mesurer la digestibilité iléale des acides aminés des issues de meunerie chez le porc et d'en déterminer les principaux facteurs de variation. Dans ce but, dix lots commerciaux de coproduits de meunerie (3 lots de farine basse, 4 lots de remoulage et 3 lots de sons) ont fait l'objet d'une caractérisation analytique et d'une mesure de digestibilité iléale des acides aminés. Les caractéristiques suivantes ont été analysées : azote, acides aminés, amidon, matière minérale, matière grasse, cellulose brute (CB), NDF (neutral detergent fibre), ADF (acid detergent fibre), ADL (acid detergent lignin) et teneur en azote du résidu NDF (NNDF). Chacun des lots a été testé sur quatre porcs mâles Ann. Zootech. 49 (2000) 55-65 55

Nutritive value of wheat and wheat by-products in pig nutrition: A review

“…In another study, the SID of total AA was 19 percentage units lower in WB compared to WM. The greatest differences were observed for glycine, lysine, threonine, alanine and aspartic acid and the smallest for arginine, glutamic acid, tryptophan and histidine (Jondreville et al, 2000).…”

“…It is composed of the pericarp and the outermost tissues of the seed, including the aleurone layer with variable amounts of remaining starchy endosperm (Jondreville et al, 2000;Hassan et al, 2008). Wheat bran constitutes almost 10% of the total weight of wheat milled for flour (Hassan et al, 2008).…”

“…However, contents of glutamic acid (292 and 263 vs. 153 and 256 g/kg CP) and proline (95 and 89 vs. 72 g/kg CP) are higher in wheat and wDDGS in comparison to WB and WM (data not shown; for proline there are no data for WB available). On the one hand, the higher contents of arginine, lysine and aspartic acid in WB and WM compared to wheat and wDDGS correspond to the high concentrations of these AA in the protein fractions albumin and globulin which are located in the outer layer of the wheat grain (Taverner and Farrell, 1981;Jondreville et al, 2000). On the other hand, the storage proteins (prolamins and glutelins) of the endosperm contain high amounts of proline and glutamine which, in turn, is reflected in higher contents of these AA in wheat and wDDGS compared to WB and WM (Jondreville et al, 2000).…”

“…Moreover, the use of wheat for bio-ethanol production results in the production of various by-products such as wDDGS, wheat wet distillers solubles and condensed distillers solubles (Widyaratne and Zijlstra, 2007a;Pahm et al, 2008b;Pedersen and Lindberg, 2010). By-products of wheat milling are of considerable economic significance as they represent 25% of the original grain (Jondreville et al, 2000). They can reduce feed costs considerably but vary in nutritional value which, in turn, may limit the efficient use of wheat by-products both in poultry and pig nutrition (Slominski et al, 2004).…”

Ileal digestibility of amino acids and estimates of endogenous amino acid losses in pigs fed wheat, triticale, rye, barley, maize and sorghum

“…All chemical analyses were performed in duplicate as previously described [31]. Each batch of cereal, each diet and each pooled sample of ileal digesta were analysed for N and AA contents.…”