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Diet‐induced alterations in lysine catabolism in pig liver
Author(s) -
Gatrell Stephanie K.,
Berg Levi E,
Grimmett Juanita G,
Wilmoth Tiffany A,
Moritz Joseph S,
Blemings Kenneth P
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.1013.4
Subject(s) - lysine , catabolism , chemistry , reductase , medicine , weanling , endocrinology , biochemistry , amino acid , biology , metabolism , enzyme
The objective was to investigate diet‐induced alterations in hepatic lysine catabolism via the saccharopine‐dependent pathway in pigs. This pathway depends on the bifunctional α‐aminoadipate δ‐semialdehyde synthase (AASS), which contains both lysine α‐ketoglutarate reductase (LKR) and saccharopine dehydrogenase (SDH) activities. In liver, LKR and SDH are restricted to the mitochondrial matrix and lysine is presumably transported through the inner membrane by one or both isoforms of ornithine transporters (ORC‐1/2). Weanling pigs (7 litters, 5/litter) were fed either a control (C, 18% CP, 0.95% lys), high protein (HP, 23% CP, 0.95% lys), low protein (LP, 13% CP, 0.95% lys), high lysine (HL, 18% CP, 1.25% lys) or low lysine (LL, 18% CP, 0.65% lys) diet for 10 days. No differences in weight gain or feed intake were detected. LKR (P<0.05) and SDH (P<0.05) activities and AASS protein abundance (P<0.01) were reduced 30, 35 and 52% respectively, in pigs consuming the LL diet relative to C. ORC‐1 mRNA expression increased (170%, P<0.05) with consumption of the HL diet and decreased (50%) with consumption of the LL diet; ORC‐2 mRNA expression was not affected by dietary treatment, although it tended to be higher (88%) in the HL and lower (76%) in the LL fed pigs relative to C. These data are consistent with ORC1/2 delivering lysine to the matrix and marks them as potential regulators of lysine catabolism (Support; HATCH WVA 470).