Some aspects of the pyridoxine (vitamin B6) requirement in weanling piglets

Abstract

Four trials were carried out to determine the optimal level of dietary pyridoxine (vitamin B6) and its interaction with riboflavin (vitamin B2) in early-weaned piglets. In Trial 1, twelve piglets were tube-fed graded supplements of B6, 0, 10, 50 or 100 mg/kg. The level of 50 mg/kg maximized B6in red blood cells (P<0·05). In Trial 2, thirty-six piglets were tube-fed with four combinations of B6(0v. 50 mg/kg) and B2(0v. 25 mg/kg). The B6supplement increased (P<0·01) B6in red blood cells. C-peptide and insulin responses to intravenous glucose tended (P<0·08) to or decreased (P<0·03) with B2while no effect was observed on glucose. After gastro-enteral glucose, dietary B2depressed C-peptide and insulin responses in B6-unsupplemented piglets and increased them in B6-supplemented piglets (P<0·03). The glucose response tended to be higher in B6-supplemented piglets (P<0·06). Trials 3 and 4 were carried out in commercial conditions using either B6and/or B2supplements given during 2 weeks after weaning (Trial 3) or a B6supplement alone (50 mg/kg) given between 2 (weaning) and 10 weeks of age. Despite a marked and persistent increase (P<0·01) of B6in red blood cells in B6-supplemented piglets, the effect on growth performance was either none (P>0·39; Trial 3) or marginally lower (<−2 %;P<0·03; Trial 4). In conclusion, it appears that a dietary supplement of 50 mg/kg B6saturated the red blood cell pool in B6and influenced, along with B2, the glucose homeostasis through the entero-insular axis. Nevertheless, such metabolic effects are not reflected on growth performance.