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Temporal changes in biochemical indices of sulphur amino acid (SAA) metabolism in the vitamin B‐6 deficient piglet
Author(s) -
Zhang Zhenbin,
House James D.
Publication year - 2006
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.20.4.a8-a
Subject(s) - weanling , medicine , endocrinology , pyridoxal , chemistry , homocysteine , metabolism , casein , pyridoxine , vitamin , pyridoxal phosphate , biochemistry , biology , phosphate , enzyme , cofactor
The impact of vitamin B‐6 deficiency on temporal changes in markers of SAA metabolism was determined in weanling pigs. Pigs (5.3 kg; n=6 per group) were fed a semi‐purified diet (20.5% casein; 3474 kcal ME/kg) containing either 0 or 3 mg pyridoxine HCl/kg diet, using a pair‐feeding design. Feed intake was measured continuously, and growth data and blood samples were collected weekly for 6 weeks. Animals were killed at the end of 6 weeks, and tissue samples harvested. Plasma pyridoxal‐5‐phosphate (PLP) was quantified by radioenzymatic assay. Total homocysteine (Hcy) and cysteine (Cys) were measured by reverse‐phase HPLC. From the 4 th week until the end of trial, vitamin B‐6 deficiency decreased average daily gain and feed efficiency (p<0.05), despite the pair‐feeding. In B‐6 deficient pigs, plasma PLP decreased substantially after the first week (37 vs.14 nM). At 6 weeks, plasma PLP was significantly higher in control vs. B‐6 deficient pigs (36 vs 5 nM; p<0.0001). Significant decreases in plasma Cys and increases in plasma Hcy, due to B‐6 deficiency, were detected from the 3 rd week (p<0.0001). From the 3 rd to 6 th week, plasma Hcy in controls was 17.70, 13.51, 11.48, and 13.28 μ M, respectively. Plasma Hcy in deficient pigs, however, was 332.48, 403.19, 337.94, and 479.91 μM, respectively. Similarly, vitamin B‐6 deficiency decreased hepatic Cys (164.03 vs. 86.31 nmol/g liver, p=0.04) but increased hepatic Hcy (16.06 vs. 307.41 nmol/g liver, p=0.001). These results provide justification for a 4 week period to establish a vitamin B‐6 deficiency in piglets. This data is critical to the implementation of studies designed to quantify the impact of vitamin B‐6 status on rates of transsulphuration in pigs. Supported by NSERC