Effects of long-term parenteral administration of vitamin B₆on B₆status and some aspects of the glucose and protein metabolism of early-weaned piglets

Abstract

The present experiment aimed to determine the effect of feeding level and parenteral supplements of vitamin B 6 (pyridoxine) on B 6 status as well as on glucose, C-peptide, insulin, a-amino-N and urea after a gastric bolus of glucose in weaned piglets; the plasma tryptophan, xanthurenic acid and kynurenine responses to a gastric bolus of tryptophan were also measured. Forty-two piglets weaned at 2 weeks of age were distributed in seven blocks of six animals each. Within each block, the animals were assigned to the following factorial treatments: two levels of feeding (28 (F28) and 56 (F56) g/kg 0´75 per d) administered by gastric-tube feeding and three levels of parenteral (intramuscular injections) vitamin B 6 (0 (B 6 0), 15 (B 6 15) and 30 (B 6 30) mg/ d). In B 6 0 piglets, a decrease of 30 % and 20 % in erythrocyte and plasma pyridoxal-5-phosphate respectively, were observed during the 2 weeks post-weaning. In supplemented piglets, the erythrocyte pyridoxal-5-phosphate was maximised in B 6 15 piglets at a level 3±4 times higher than in B 6 0 piglets P , 0´003X However, in plasma the maximal pyridoxal-5-phosphate concentration was reached in F28±B 6 30 piglets P , 0´058X The glucose and insulin responses to a gastric bolus of glucose were lower, and the post-bolus decrease of glucose was slower, in F28 than in F56 piglets P , 0´0001X The insulin:C-peptide ratio was 25 % greater in B 6 15 piglets P , 0´082X After the bolus of glucose, the aminoacidaemia decreased differentially according to treatments P , 0´047 while the uraemia was at least 2-fold higher P , 0´001 in F28 piglets than in F56 piglets and tended to be maximised in B 6 30 piglets P , 0´074X The response of plasma tryptophan to the gastric bolus of tryptophan was 11 % lower in B 6 30 piglets P , 0´057X The plasma concentration of kynurenine increased continuously during the post-bolus period and this response was more marked in F56 P , 0´002 and in B 6 30 piglets P , 0´02X Xanthurenic acid was undetectable in any of the treatments. The measurements on pyridoxine status suggest that the present basal dietary level of B 6 (7´7 mg/kg) was not sufficient to cover the metabolic needs. For many criteria, an optimal level was reached at 15 mg/d parenteral B 6 but the response of urea to glucose bolus suggests that 30 mg/d was detrimental. Further studies are necessary to determine the dietary level of B 6 equivalent to the present optimal parenteral supplements and its eventual effects on B 6 status and post-weaning growth performance of piglets.

Gene expression of porcine blastocysts from gilts fed organic or inorganic selenium and pyridoxine

“…a The calculated compositions for ME, CP, lysine, Ca, and P of the basal diet were 2702 kcal/kg, 14.0, 0.6, 1.0, and 0.6% respectively. b The basal Se and pyridoxine contents of the diet were 0.3 and 1.7 mg/kg respectively (analytical values determined according to Matte et al (2001) and Giguère et al (2005) respectively).…”

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

“…The weaning period induces, in piglets, drastic challenges for homeostasis of water-soluble vitamins such as folates (Matte et al 1990;Letendre et al 1991), vitamin B 12 (Bilodeau et al 1989) and vitamin C (Yen & Pond, 1988). It is also the case of pyridoxine (vitamin B 6 ) for which the status is low at weaning (Matte et al 1997(Matte et al , 2001. In fact, sow milk is a poor dietary source of B 6 (Benedikt et al 1996), approximately 0•4 mg/ml, which is believed to cover less than half the amount required to sustain the piglet growth rate (Coburn, 1994).…”

Pyridoxine (Vitamin B6) and the Glutathione Peroxidase System; a Link between One-Carbon Metabolism and Antioxidation

“…Circulatory P-5-P must be hydrolyzed (by extracellular alkaline phosphatases) to pyridoxal that can cross cell membranes and then is trapped intracellularly by phosphorylation. Pyridoxal-5-P is over six times more concentrated in erythrocytes than in plasma possibly because the Schiff base with hemoglobin is stronger than the one with albumin, driving the uptake of the vitamin to erythrocytes; however, its storage in these cells is saturable [16,19]. …”