Feeding the Pigs’ Immune System and Alternatives to Antibiotics

Diet formulation and feeding strategies may be used to boost the pigs’ immune system and reduce the negative impact of weaning. Post-weaning diarrhea can be reduced or prevented by feeding diets that have low concentrations of crude protein. Such diets may supply fewer amino acids than recommended and pig growth rate may be reduced, but if pigs are provided a diet with a normal or elevated concentration of protein after the immediate post-weaning period, then the overall post-weaning performance will not be compromised. Diets that are based on barley, oats, or naked oats have been shown to improve pig performance compared with diets based on wheat or corn, and there is evidence that the fiber fraction in barley and oats help improve intestinal health of pigs. However, it has also been shown that diets based on cooked white rice may improve performance and the immune status of the pig. Diets fed in a liquid or in a fermented liquid form improve pig performance compared with diets fed in a dry form, and the liquid diets help maintain intestinal integrity during the post-weaning period. It is, therefore, recommended that weanling pigs should be fed liquid diets to maximize performance. Many feed additives are available for inclusion in diets fed to pigs. Positive responses on pig performance have been reported in some, but not all, studies in which the inclusion of acidifiers, probiotics, or pre-biotics was studied. However, there are many unknowns regarding the usage of these additives, and the responses to the inclusion of them are not always predictable.