title: Feeding high levels of vitamin D3 does not improve tenderness of callipyge lamb loin chops.
abstract: The objective of this study was to determine whether feeding high doses of vitamin D3 7 d before slaughter would increase muscle Ca++ levels and result in more tender loin chops. Market lambs (n = 4 callipyge and 4 normal in Exp. 1, and n = 16 calipyge and 16 normal in Exp. 2) were randomly and equally assigned to feeding groups based on callipyge genotype and experimental diet, (vitamin D3 or control). Serum Ca++, muscle Ca++, Warner-Bratzler shear force, and troponin-T degradation data were analyzed. In Exp. 1, vitamin D3 was supplemented at 1 or 2 x 10(6) IU/d. The 2 x 10(6) IU dose resulted in the greatest serum Ca++ reponse and was chosen for Exp. 2. In Exp. 2, serum Ca++ concentration was higher (P < 0.05) for normal and callipyge lambs fed the vitamin D3 diet than for the control diet fed lambs. Muscle Ca++ concentrations, however, were not higher (P = 0.28) for the vitamin D3-fed lambs. Warner-Bratzler shear values were higher (P < 0.05) for callipyge than for normal lambs, but no differences were observed with vitamin D3 supplementation. These data were supported by results from Western blot analysis of troponin-T degradation, in which no differences were observed for vitamin D3 vs control diet lambs at 14 d postmortem. This experiment showed that feeding 2 x 10(6) IU/d of vitamin D3 to market lambs, callipyge or normal, raised serum Ca++ concentration, but did not increase muscle Ca++ concentration. This lack of response in muscle Ca++ was likely the reason that no differences were observed for Warner-Bratzler shear force values or troponin-T degradation data between the vitamin D3 and control loin chops. A higher dose of vitamin D3 may be required to improve tenderness.
authors.affiliation: Iowa State University, Ames 50011, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Wiegand
authors.forename: F C
authors.initials: FC
authors.lastname: Parrish
authors.forename: D G
authors.initials: DG
authors.lastname: Morrical
authors.forename: E
authors.initials: E
authors.lastname: Huff-Lonerga
mesh_terms: D000818:Animals; D015153:Blotting, Western / Q000662:veterinary; D002118:Calcium / Q000097:blood; D002762:Cholecalciferol / Q000008:administration & dosage*; D004032:Diet / Q000662:veterinary*; D005838:Genotype; D016018:Least-Squares Analysis; D008460:Meat / Q000592:standards*; D012756:Sheep / Q000235:genetics* / Q000254:growth & development; D020107:Troponin T / Q000032:analysis
chemical_list: D020107:Troponin T; D002762:Cholecalciferol; D002118:Calcium