ANALYSIS OF RELATIONSHIPS BETWEEN ZINC UP TAKE, ITS DIGESTIBILITY ANDRETENTION IN YOUNG-PIGS

The objective of the paper was to describe the effect of basic indicat ors on zinc digestibility and retention on the basis of regression and correlation analyses. The shape of regression curves has indicated th at zinc digestion as well as zinc retention per unit of metabolic size showed a parabolic dependence with the growing zinc uptake (y = 1.952 - 0.621 x + 0.069 x2; I(k) = 0.747, y = Zn deposition in mg/W0.75; x = Zn uptake in mg/W0.75). Zinc digestion and zinc retention per unit o f metabolic size had a permanently growing trend. Similar trends like those of absolute zinc retention and digestion per unit of metabolic s ize were determined for relative values of zinc digestibility and rete ntion. According to our calculations the lowest relative zinc digestio n (20.6%) from zinc uptake corresponded to the level of 6.1 mg of zinc uptake per unit of metabolic size, and/or the lowest relative zinc re tention (15.44%) corresponded to the level of 5.7 mg zinc uptake per u nit of metabolic size. Besides the determinative effect of zinc uptake on zinc retention, the effect of calcium uptake and the effect of met abolic size of the individual was also obvious. While the effect of ca lcium influenced zinc retention from 2.8% and 27.46% in the given mode l, the effect of metabolic size is much more significant and equals 49 .53 and/or 51.23% out of the total effect of particular factors of mul tiple regression. According to the values of calculated coefficients, it is possible to expect certain regression in zinc retention with the growing metabolic size. As for the effect of age, it was not a factor influencing zinc retention in a decisive way.