Metabolic inflammation (MI) occurs in the small intestines of production animals after eating, and its level of response depends on the dietary energy of feed. High energy feed in large quantities will cause increased MI, which can lead to muscle catabolism, decreased feed intake, and susceptibility to pathogen infection. The anti-inflammatory properties of antibiotics and antimicrobial growth promoters (AGP) reduce MI, and result in increased growth performance. Antibiotics are used at sutherapeutic levels and the spread of pathogen resistance, and this indicates it is not the antibiotic properties causing weight gain. The spread of bacterial resistance and negative public opinion calls for stopping antibiotic use, and alternatives with anti-inflammatory properties should be able to be used just as effectively. The alternatives include NSAIDs or plant options, and should be nonphamaceutical, require low doses, and be able to reach the small intestine without encapsulation. New options can be evaluated using in vitro assays with lipopolysaccharide-activated macrophages, and comparing the results to a AGP reference.