+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: not found

      What Do We Feed to Food-Production Animals? A Review of Animal Feed Ingredients and Their Potential Impacts on Human Health

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.



          Animal feeding practices in the United States have changed considerably over the past century. As large-scale, concentrated production methods have become the predominant model for animal husbandry, animal feeds have been modified to include ingredients ranging from rendered animals and animal waste to antibiotics and organoarsenicals. In this article we review current U.S. animal feeding practices and etiologic agents that have been detected in animal feed. Evidence that current feeding practices may lead to adverse human health impacts is also evaluated.

          Data sources

          We reviewed published veterinary and human-health literature regarding animal feeding practices, etiologic agents present in feed, and human health effects along with proceedings from animal feed workshops.

          Data extraction

          Data were extracted from peer-reviewed articles and books identified using PubMed, Agricola, U.S. Department of Agriculture, Food and Drug Administration, and Centers for Disease Control and Prevention databases.

          Data synthesis

          Findings emphasize that current animal feeding practices can result in the presence of bacteria, antibiotic-resistant bacteria, prions, arsenicals, and dioxins in feed and animal-based food products. Despite a range of potential human health impacts that could ensue, there are significant data gaps that prevent comprehensive assessments of human health risks associated with animal feed. Limited data are collected at the federal or state level concerning the amounts of specific ingredients used in animal feed, and there are insufficient surveillance systems to monitor etiologic agents “from farm to fork.”


          Increased funding for integrated veterinary and human health surveillance systems and increased collaboration among feed professionals, animal producers, and veterinary and public health officials is necessary to effectively address these issues.

          Related collections

          Most cited references 67

          • Record: found
          • Abstract: found
          • Article: not found

          Occurrence and diversity of tetracycline resistance genes in lagoons and groundwater underlying two swine production facilities.

          In this study, we used PCR typing methods to assess the presence of tetracycline resistance determinants conferring ribosomal protection in waste lagoons and in groundwater underlying two swine farms. All eight classes of genes encoding this mechanism of resistance [tet(O), tet(Q), tet(W), tet(M), tetB(P), tet(S), tet(T), and otrA] were found in total DNA extracted from water of two lagoons. These determinants were found to be seeping into the underlying groundwater and could be detected as far as 250 m downstream from the lagoons. The identities and origin of these genes in groundwater were confirmed by PCR-denaturing gradient gel electrophoresis and sequence analyses. Tetracycline-resistant bacterial isolates from groundwater harbored the tet(M) gene, which was not predominant in the environmental samples and was identical to tet(M) from the lagoons. The presence of this gene in some typical soil inhabitants suggests that the vector of antibiotic resistance gene dissemination is not limited to strains of gastrointestinal origin carrying the gene but can be mobilized into the indigenous soil microbiota. This study demonstrated that tet genes occur in the environment as a direct result of agriculture and suggested that groundwater may be a potential source of antibiotic resistance in the food chain.
            • Record: found
            • Abstract: found
            • Article: not found

            Variant Creutzfeldt-Jakob disease.

             John Collinge (1999)
            It is clear that the prion strain causing bovine spongiform encephalopathy (BSE) in cattle has infected human beings, manifesting itself as a novel human prion disease, variant Creutzfeldt-Jakob disease (CjD). Studies of the incubation periods seen in previous epidemics of human prion disease and of the effect of transmission barriers limiting spread of these diseases between species, suggest that the early variant CJD cases may have been exposed during the preclinical phase of the BSE epidemic. It must therefore be considered that many cases may follow from later exposure in an epidemic that would be expected to evolve over decades. Since the number of people currently incubating this disease is unknown, there are concerns that prions might be transmitted iatrogenically via blood transfusion, tissue donation, and, since prions resist routine sterilisation, contamination of surgical instruments. Such risks remain unquantified. Although variant CJD can be diagnosed during life by tonsil biopsy, a prion-specific blood test is needed to assess and manage this potential threat to public health. The theoretical possibility that BSE prions might have transferred to other species and continue to present a risk to human health cannot be excluded at present.
              • Record: found
              • Abstract: found
              • Article: not found

              Antibiotics in animal feed and their role in resistance development

              Animals and humans constitute overlapping reservoirs of resistance, and consequently use of antimicrobials in animals can impact on public health. For example, the occurrence of vancomycin-resistant enterococci in food-animals is associated with the use of avoparcin, a glycopeptide antibiotic used as a feed additive for the growth promotion of animals. Vancomycin-resistant enterococci and vancomycin resistance determinants can therefore spread from animals to humans. The bans on avoparcin and other antibiotics as growth promoters in the EU have provided scientists with a unique opportunity to investigate the effects of the withdrawal of a major antimicrobial selective pressure on the occurrence and spread of antimicrobial resistance. The data shows that although the levels of resistance in animals and food, and consequently in humans, has been markedly reduced after the termination of use, the effects on animal health and productivity have been very minor.

                Author and article information

                Environ Health Perspect
                Environmental Health Perspectives
                National Institute of Environmental Health Sciences
                May 2007
                8 February 2007
                : 115
                : 5
                : 663-670
                [1 ] Johns Hopkins Center for a Livable Future, Bloomberg School of Public Health, Baltimore, Maryland, USA
                [2 ] Maryland Institute for Applied Environmental Health, College of Health and Human Performance, University of Maryland, College Park, Maryland, USA
                [3 ] Lisa Y. Lefferts Consulting, Nellysford, Virginia, USA
                Author notes
                Address correspondence to A.R. Sapkota, Maryland Institute for Applied Environmental Health, College of Health and Human Performance, University of Maryland, College Park, 2306 HHP Building, College Park, MD 20742 USA. Telephone: (301) 405-2438. Fax: (301) 405-8397. E-mail: amy@

                The authors declare they have no competing financial interests.

                This is an Open Access article: verbatim copying and redistribution of this article are permitted in all media for any purpose, provided this notice is preserved along with the article's original DOI


                Comment on this article