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Determination of standardized ileal crude protein and amino acid digestibilities in protein supplements for piglets

Urbaityte, R., Mosenthin, R., Eklund, M., Piepho, H.P., Rademacher, M.
Animal 2009 v.3 no.12 pp. 1696-1705
piglets, weanlings, weaning, feeds, protein supplements, nutritive value, nutritional adequacy, feed quality, digestibility, ileum, crude protein, amino acids, reference standards, soybeans, soybean meal, soy protein, fish meal, wheat gluten, feed processing, soybean products
The objective of the study was to determine standardized ileal digestibilities (SID) of crude protein (CP) and amino acids (AA) in six ingredients commonly used in weanling pigs diets. The ingredients consisted of extruded soybeans (SB(e)), high-protein soybean meal (SBM(hp)), soy protein concentrate (SPC), hydrolyzed wheat gluten (WG(h)), conventional fish meal 1 (FM1) and extracted fish meal 2 (FM2(e)). Each assay feed ingredient was added to a purified cornstarch-based basal diet supplemented with casein and crystalline AA, and SID of CP and AA of assay ingredients were estimated using the difference method. A total of 12 3-week-old barrows were surgically fitted with T-cannulas at the distal ileum. The piglets were allocated to four simultaneous 3 × 3 Latin-square designs with three animals and three periods each, resulting in six observations per assay diet. After 3 to 5 days recovery from surgery, each assay diet was fed at a level of 30 g/kg body weight. Each experimental period consisted of 5 days for adaptation to the assay diets and 2 days for ileal digesta collection. The SID of CP, Lys, Met, Thr and Trp were 73%, 78%, 76%, 66% and 71% in SB(e); 80%, 84%, 87%, 75% and 81% in SBM(hp); 86%, 89%, 89%, 78% and 83% in SPC; 87%, 60%, 88%, 76% and 79% in WG(h); 87%, 92%, 94%, 86% and 86% in FM1; and 79%, 86%, 89%, 80% and 74% in FM2(e), respectively. The greatest SID of indispensable AA were observed for FM1 and SPC (SID >or= 85% for most indispensable AA), followed by WG(h), FM2(e) and SBM(hp) (SID >or= 80% for most indispensable AA) and the smallest SID were obtained for SB(e) (SID < 80% for most indispensable AA). The SID of CP and indispensable AA in both types of fish meal, SBM(hp) and WG(h) were similar to SPC (P = 0.063 to 0.855), except for Arg (P = 0.010) and Lys (P = 0.001) in WG(h), and Phe (P = 0.044) and Trp (P = 0.037) in FM2(e). The SID of CP and indispensable AA were smaller in SB(e) compared with SPC (P < 0.001 to P = 0.017), except for Lys (P = 0.136). The SID of CP and indispensable AA were consistently smaller in FM2(e) compared with FM1 with significant differences for CP (P = 0.035), Phe (P = 0.028) and Trp (P = 0.008). Digestibility values measured in the present study can be used to formulate diets for piglets based on standardized ileal digestible contents of CP and AA.