4. Discussion
Several feeding trials have been conducted to evaluate
the effects of BioPlus 2B® in pig diets. Previous studies
have suggested that supplementation of the diets of
nursery pigs with BioPlus 2B® did not improve the
growth performance (Kritas and Morrison, 2004; Min
et al. 2004), however, these results have not always been
consistent. For example, Gracia et al. (2004) reported that
dietary 0.04%BioPlus 2B® could benefit ADG and ADFI
during the prestarter period and the overall prestarter–
finishing period. Similarly, Munoz et al. (2007) suggested
that addition of 0.05%BioPlus 2B® to the diet of finishing
pigs improved ADFI, but had no effect on ADG or the G:
F ratio. The variation in the results of these studies can be
ascribed to several factors, including the age of the pigs,
the dose of BioPlus 2B®, diet composition, feed form and
interaction with other dietary feed additives (Chesson1994). In addition, probiotic administration strategies can
also impact the effects of the probiotic. For example,
Róbert and Gabriel (2006) suggested that addition of
0.04% BioPlus 2B® at different periods had different
effects on the ADG of young pigs. In our study, the pigs'
diets were supplemented with BioPlus 2B® while they
were between the ages of 56 and 91days, which is similar
to the period in which group C of their study received a
dietary probiotic supplement (42–91days). The lower
amount of improvement in ADG in BioPlus 2B® treatments
observed in both of these studiesmay have occurred
due to the short treatment period, therefore, the effects of
BioPlus 2B® should be evaluated when it is provided to
pigs at an earlier age or for a longer period of time.