Effects of sewage sludge-fertilized corn fed to growing swine

Swine (2 groups) fed a ration containing 79% corn from sewage sludge-fertilized plots for 8 weeks may have had a modest performance advantage over swine fed corn from plots heavily fertilized with commercial nitrogen. Sludge-fertilized corn feeding-related deviations from population normals for electroencephalograms, electrocardiograms, clinical chemistry, or histopathology were not observed; however, swine fed sludge-fertilized corn differed significantly from the control swine for certain physiologic and biological characteristics, indicating possible interference with glucose metabolism and microsomal mixed-function oxidase activity. Control swine had mild microcytic anemia associated with parasitism, but swine in the principal groups were less adversely affected, probably due to higher iron intake. Corn heavily fertilized with sewage sludge from an urban-industrial complex can be safely fed to swine, based on these results, but it might be advantageous to feed on a short-term or intermittent schedule. Residues of heavy metals in the animal products must be examined.