Ways to improve performance
Industrialized production has placed greater demands on animal husbandry and given rise to several challenges related to gut health, including dysbiosis, reduced nutrient digestibility and impaired barrier function. These put pressure on farm profitability and explain, at least in part, the motivations for sub-therapeutic application of antibiotics for disease prevention and growth promotion. As antibiotics enabled animals to grow faster and gain weight more efficiently through reducing inflammation and modulating gut microbiota, their use in growth promotion became common practice. Van Boeckel et al. (2015) estimate that the global average annual consumption of antimicrobials per kilogram of animal produced is 2 and 3 times higher in chicken (148 mg/kg) and pigs (172 mg/kg) respectively compared to cattle (45 mg/kg). Furthermore, global compound feed production and antibiotic consumption data indicate that, on average, each ton of feed contains 66 grams of antibiotics, and this figure is estimated to rise in the future. Teillant and Laxminarayan (2015) have pointed out in their study that recommended dosage of sub-therapeutic antibiotics has increased over last 60 years, from 10-20 g/ton in the early 1950s to 40-50 g/ton in the 1970s, to 30-110 g/ton nowadays.
Teillant and Laxminarayan (2015) report that antibiotic growth promoters lost productivity in the post-2000 era compared to earlier studies. This might be a result of increasing antibiotic resistance levels among microorganisms, which is not only affected by antibiotic use in livestock, but also in human medicine. In addition to the fact that antibiotic resistance triggers an increase in production costs, antibiotic resistance in animals may affect human disease control. Therefore, besides holistic approach (better management, vaccination programs, biosecurity measurers, and feeding strategy) significant effort has been paid to novel growth promoters (NGPs) in order to reduce usage of AGPs in animal husbandry.
Economic impact of gut health
Concentration and consolidation has been accelerated in agriculture especially in livestock production where the number of large animal feeding operations has been sharply increased in last decades. Intensive, automatized production systems together with high genetic potential, high quality feeding, biosecurity and management programs have to be established in order to maintain profitability in a highly volatile market where margins are often tight.
When gut health is harmed by malnutrition, bacteria or toxic compounds, the host will try to restore optimal condition through an immune response. Such defense mechanisms do require energy and nutrients, which compete with the animal´s nutrient demand for maintenance and growth.
Good gut health is the best growth promoter.