This image shows the intestinal tract of a chicken. A healthy gastrointestinal (GI) tract can help poultry achieve optimal production of meat or eggs. The GI tract for chicken has two essential functions: digestion/absorption and immunity. The intestinal mucosa provides an efficient barrier between unfriendly luminal content and the host's internal tissues. A cohesive alliance between the mucus layer, epithelial cells, microbiota and immune cells in the intestine is critical for the intestinal barrier functions.
The right balance of microbiota creates an opportunity for positive gut health conditions, especially the role of commensal microbiota. Commensal microbiota helps develop gut structure and morphology, control immune responses, block intestinal pathogens and aid in the absorption and digestion of nutrients. Suppressing pathogenic bacteria and promoting beneficial bacteria will help maintain healthy intestinal microflora. Good gut health in poultry has been associated with the healthy ecological equilibrium of the GI microflora, which is believed to protect against harmful bacterial colonization and to stimulate an immune response.
Changes in the composition of a bird's microflora can have positive and negative effects on the health and maturity of poultry. Many factors can affect the composition of a bird's bacterial community including diet, age, antibiotic us and infection.1
Necrotic Enteritis and Coccidiosis are often the most detrimental in poultry production. They can deplete profits for producers significantly per bird.2,3
For 60 years, antibiotic growth promoters have been used in livestock feed around the world. Their benefits include improved feed conversion rates, growth and a reduction in disease occurrences. Recently, consumer pressure has advocated the reduction in the use of antibiotics, fearing microbes could develop resistance and cause untreatable disease conditions in humans.4 As a result, the industry has been forced to rethink the use of antibiotics in animal feed. Now there is an ever-increasing interest in naturally derived antibiotic alternatives.
An antibiotic alternative is expected to have the same beneficial effects offered by antibiotics:
Common alternatives include probiotics, prebiotics, organic acids, phytogenics and essential oils. An ideal combination of two or more will increase the chances of optimum performance.
Probiotics are live microbial feed supplements, which help the host animal by improving its intestinal microbial balance. Probiotics may increase the healthy microbiota population, which can support inhibition of pathogenic microbes in the gut.
An ideal probiotic should be of host origin, non-pathogenic, resist acidic gut conditions, produce antimicrobial compounds, improve commensal bacterial growth, modulate the immune response, improve animal performance and withstand feed processing conditions. Kemin created its patented direct fed microbial made from a naturally occurring strain of Bacillus subtilis PB6, found in the gut of healthy chickens.
Organic acids have also shown beneficial effects on the intestinal health and performance of birds like improved body weight gains and feed conversion ratios. Among the benefits attributed to organic acids are improving intestinal integrity, reducing inflammation, reducing pathogen load and improving digestion.5Blends of organic acids have been utilized as an effective means to positively affect intestinal health because of multiple modes of action. More recent technology has been utilized to protect (encapsulate) some organic acids because they have a sustained and targeted release with reduced odor. Supplementation of organic acids can modify enteric bacterial population so they can be used along with probiotics.
A variety of herbs and botanical products have been reported to impart advantageous effects on intestinal integrity, gut conditions and microflora through their biologically active components. The beneficial effects of essential oils may also include stimulation of feed intake and digestive secretions, antibacterial, antiviral, coccidiostatic, anthelmintic as well as anti-inflammatory and antioxidant effects.5
Fats and oils are a key part of animal diets, but according to studies, fat digestion is harder in the beginning stages of life.6 Biosurfactant use provides an effective way to improve absorption of oils and fats from the feed through enhanced emulsification, improved fat hydrolysis and easier and smaller micelle formation. Biosurfactants can also improve the absorption of other nutrients, vitamins and carotenoids.
Mold found in animal feed can have serious negative effects on animal health and production. No poultry feed is completely free of mold; in fact, in most cases there are multiple molds present. To prevent the toxic effects of molds, several mold inhibitors have been developed for use in animal feed.
A prebiotic is an indigestible direct component that influences an animal's digestive tract by using bacteria already present in the intestine to outnumber pathogenic bacteria. In one study, all in-feed supplementation with a prebiotic, a probiotic, or an organic acid alone or in combination caused significant improvement in the broiler weight in comparison to the control.7 Therefore, dietary prebiotics may be more fruitful when combined with probiotics or an organic acid.
2Wade, B., and A. Keyburn. 2015. The true cost of necrotic enteritis. Poultry World. Retrieved September 14, 2017. 
3De Guessem, M., et al. 2007. Coccidiosis in poultry: Review on diagnosis, control, prevention and interaction with overall gut health. 16th European Symposium on Poultry Nutrition. 253-261.
4El Amouri, S. 2015. Progressive ban has led to more antibiotic alternatives. Poultry World. Retrieved September 14, 2017. 
5Roberts, T., et al. 2015. New issues and science in broiler chicken intestinal health: Emerging technology and alternative interventions. The Journal of Applied Poultry Research. 24(2):257-266.
6Leeson, S. 1993. Recent advances in fat utilization by poultry. Recent Advance in Animal Nutrition in Australia. University of New England, Armidale, Australia. 170-181.
7Bozkurt, M., et al. 2009. The effect of single or combined dietary supplementation of prebiotics, organic acid and probiotics on performance and slaughter characteristics of broilers. South African Journal of Animal Science. 39(3):197-205.