Benzoic acid linearly increased the ATTD (Pb0.01) of Sodium;
however, benzoic acid linearly decreased (Pb0.05) retention
of Sodium by 9% in the present study (Table 5). Benzoic acid
linearly decreased (Pb0.05) the ATTD of Cl and linearly
reduced (P=0.001) retention of Cl by 0.99 g day−1. Benzoic
acid linearly increased the urinary excretion of Sodium and
Cl (P=0.001). The large increases in the urinary excretions
of Sodium and Cl with the inclusion of benzoic acid explain their
decreased retention. These results are not in agreement with
previous studies (Mroz et al.,1996,1998) indicating that, even
at a dietary inclusion level of 4.8%, Ca benzoate did not
increase the urinary excretions of Sodium and Cl. The form of
dietary supplementation of benzoic acid, acid vs. salt, might
have been responsible for the differences among studies. The
reduced Na and Cl balance in conjunction with supplementation
of benzoic acid might be a new phenomenon observed
under the conditions of the present study. The importance
relative to Sodium and Cl requirements was not studied in the
present study, but extra salt might have to be supplemented
in practical diet formulation. Overall, the improved utilization
of dietary minerals might be one of the underlying mechanisms
that explain the improved growth performance of
weaned pigs following the inclusion of 5 g kg−1 benzoic
acid in swine feeds (Torrallardona et al., 2007).