Effect of wheat bran and pectin on the absorption and retention of phosphorus, calcium, magnesium and zinc by the growing pig.

Two separate balance experiments of P, Ca, Mg and Zn were carried out on 5 lots of 4 growing pigs each (35-40 kg) adapted for 3 weeks to one of the diets studied. In the first experiment, the control diet was compared with a diet containing 20% of coarse wheat bran, thus richer in minerals, the quantities ingested not being equalized. In the second experiment, three diets were compared: a control diet, a diet with 2.5% of high-methoxylated (HM) apple pectin, and a diet with 2.5% low-methoxylated (LM) apple pectin. The supplement of P and Mg provided by the wheat bran was well absorbed (apparent absorption) and retained by the pigs. On the contrary, in spite of higher intake of Ca and Zn with bran diet, the absorption of these minerals was not improved. The action of wheat bran phytase and the possible absorption of P and Mg (but not of Ca and Zn) in the large intestine could explain these results. Compared to HM pectin that had relatively little effect on mineral utilization, LM pectin drastically diminished the absorption and retention of the minerals studied and resulted in negative Ca, Mg and Zn balances. The degree of pectin esterification would thus be the main factor determining the effect of pectin on mineral availability. In conclusion, wheat bran is a source of available P and Mg for the pig but it might have an unfavorable effect on the utilization of Ca and Zn. LM pectin produces a deleterious influence on mineral balances.