Influence of high fibre diets given to gestating sows on serum concentrations of micronutrients

Abstract The objective of the present work was to evaluate the effects of high fibre diets given to sows during two consecutive gestations on the evolution of serum concentrations of some micronutrients. Eighty-eight gilts were distributed among the three following experimental diets: (1) corn-soybean meal, (2) corn cobs-wheat bran and (3) oats-oat hulls. Dietary fibre represented 14, 30 and 46% of diets 1, 2 and 3, respectively. Blood samples were taken from the jugular vein at 5, 10 and 15 wk of gestation from all sows at each parity. In the first parity, serum concentration of folates per unit of folates ingested was higher with diet 1 ( P = 0.003), whereas it was the opposite in the second gestation, serum folates being higher with diets 2 and 3 ( P = 0.02). In the first gestation, the lowest serum concentration of vitamin B 12 per unit ingested was observed in sows fed diet 2 ( P ≤ 0.05); in the second gestation, serum vitamin B 12 was lower for sows fed diets 2 and 3 than for those fed diet 1 ( P ≤ 0.05); Serum concentrations of calcium, phosphorus, copper and zinc per unit of mineral ingested were lower in sows fed the two high fibre diets ( P ≤ 0.05). Serum concentrations of these minerals were lower in second than in first parity whatever the diet ( P ≤ 0.05). Results of the present study give an indication that feeding high fibre diets to gestating sows could reduce B-complex vitamin, especially vitamin B 12 , availability. Responses of serum concentrations of minerals to dietary treatments, in spite of the limitations of these measurements, also raise the question of the effect of dietary fibre on mineral availability. Supplementary studies, mainly on mineral metabolism, need to be conducted to confirm these observations and to define precisely the composition of premixes in order to maintain the B-complex vitamin and mineral status of gestating sows fed high fibre diets at an optimum level.