Tienken Reka, Kersten Susanne, Hüther Liane, Frahm Jana, Meyer Ulrich, Dänicke Sven
Institute of Animal Nutrition, Friedrich-Loeffler-Institute (FLI), Federal Research Institute for Animal Health, Bundesallee 50, Brunswick 38116, Germany.
Vet Sci. 2015 Dec 16;2(4):440-455. doi: 10.3390/vetsci2040440.
The present study aimed to examine the effective systemic bioavailability of niacin- with particular focus on its galenic form-and feed processing. Experiment 1 was conducted with 35 dairy cows to investigate the effects of various doses of oral supplemented nicotinic acid (NA) either in differing galenic forms (non-rumen protected (nRP) rumen protected form (RP)) on serum niacin concentrations. Experiment 2 was designed as a pharmacokinetic study examining the serum niacin kinetics over 24 h after giving a single oral bolus of 24 g nRP or RP NA admixed in either pelleted or ground concentrate. In both experiments, only the niacin vitamer nicotinamide (NAM) was detected. Results of experiment 1 showed that both galenic forms at a dose of 24 g/cow daily elevated NAM concentrations at the beginning of the experiment. Despite a daily supplementation, NAM concentrations decreased continuously towards the end of the experiment which was more steeply in nRP NA ( = 0.03). On experimental day 21, NAM concentrations were higher when feeding RP NA ( = 0.03) and the highest dose (24 g/day and cow) ( < 0.01). Results of experiment 2 indicated that nRP and RP were characterized by similar pharmacokinetic profiles resulting in similar areas under the curves as a net result of the kinetic counterbalancing alterations. Pelleting seemed not to influence the relative bioavailability.
本研究旨在检测烟酸的有效全身生物利用度，尤其关注其药剂形式和饲料加工。实验1选用35头奶牛，研究不同药剂形式（非瘤胃保护型（nRP）、瘤胃保护型（RP））的不同剂量口服补充烟酸（NA）对血清烟酸浓度的影响。实验2设计为一项药代动力学研究，在单次口服24克与颗粒状或磨碎的精饲料混合的nRP或RP NA后，检测24小时内血清烟酸的动力学变化。在两个实验中，仅检测到烟酸维生素烟酰胺（NAM）。实验1结果表明，每日每头奶牛24克的两种药剂形式在实验开始时均提高了NAM浓度。尽管每日进行补充，但在实验结束时，NAM浓度持续下降，nRP NA下降得更明显（P = 0.03）。在实验第21天，饲喂RP NA时NAM浓度更高（P = 0.03），且最高剂量组（每日每头奶牛24克）更高（P < 0.01）。实验2结果表明，nRP和RP具有相似的药代动力学特征，由于动力学的相互平衡变化，曲线下面积相似。制粒似乎不影响相对生物利用度。
