Bioavailability of D-amino acids and DL-hydroxy-methionine

The relative effectiveness of liquid MHA-FA compared with DL-methionine in broiler chickens - a dose-response experiment

“…Although supplemented on a molar basis, regression analysis was performed on a product basis to make the result directly applicable to practical feed formulation (on a molar basis, relative effectiveness was 72 and 66% for BWG and FCR). The determined relative efficacy figures of the current experiment are in good agreement with the outcome of the studies by Lewis and Baker (1995) and Jansman et al (2003).…”

“…The absorption, metabolism and effectiveness of different commercial methionine sources have been investigated by physiologists and nutritionists for years (Lewis and Baker, 1995;Jansman et al, 2003). The relative effectiveness of liquid hydroxy-4-methylthiobutanoic acid (MHA-FA) compared with DL-methionine (DL-Met) is determined in a simultaneous dose-response assay in which graded levels of either source are fed to animals.…”

A novel enzymatic pre‐treatment improves amino acid utilization in feather meal fed to rainbow trout (Oncorhynchus mykiss)

“…Still, other factors must have contributed to the significant differences in BV observed between Diets 10 and 6 (PTFeM2 and PTFeM1 at 13.5 g/kg Arg; 33.5 g/kg of CP Arg). Differences in BV ( p < 0.05) between Diets 10 and 6 may be attributable to the differences in palatability (Arunlertaree & Rakyuttithamkul, ; Suloma, El‐Husseiny, Hassane, Mabroke, & El‐Haroun, ), racemized amino acids content (Friedman, Zahnley, & Masters, ; Lewis & Baker, ), CLAA content (Feron, Van Beek, Slump, & Beems, ; De Groot, Slump, Feron, & Van Beek, ) and cysteine content (Davies & Morris, ; Green & Hardy, ) between the FeMs. Those factors may have a larger impact on fish performance in 20%‐FeM diets than in 10%‐FeM diets explaining the general decrease in performance associated with high‐FeM content in the diets.…”

“…The scorched smell detected in FeM1 and PTFeM1 may also indicate heat damage of the amino acid content in the ingredients. Several studies demonstrated that treatment of protein at high temperatures can cause racemization of L to D‐amino acids (D‐AAs) that may be unavailable for metabolism (Friedman et al, ; Hayase, Kato, & Fujimaki, ; Lewis & Baker, ; Schwass & Finley, ). The level of BV of D‐arginine (D‐Arg) in fish is still unknown but was shown to be completely unavailable to rats and chicks (Baker & Boebel, ).…”

“…The Arg retention efficiency was the greatest at 13.5 g/kg Arg (33.5 g/kg of CP Arg) in fish fed diets supplemented with L-Arg. This is in agreement with previous dose-response studies with lysine or threonine in Atlantic smolts, where maximum retention efficiencies of the amino acids in question were situated at 75%-80% of their respective requirements At the 13.5 g/kg (33.5 g/kg of CP) Arg level, feed intake, weight gain and TGC of rainbow trout fed diets containing 100 g/ Several studies demonstrated that treatment of protein at high temperatures can cause racemization of L to D-amino acids (D-AAs) that may be unavailable for metabolism (Friedman et al, 1981;Hayase, Kato, & Fujimaki, 1975;Lewis & Baker, 1995;Schwass & Finley, 1984).…”