• Heat stress • Vaccination •


• Ascites • Coccidiosis There are numerous benefits from reducing the antioxidant status in production animals which extend beyond the growth phase. Studies have shown both improved meat qual- ity and shelf life extension when chickens received dietary polyphenols during their growth phase. Furthermore, the meat from these animals also had reduced oxidation levels when compared to meat from untreated animals.

Flavonoids perform many important physiological actions, including: • Scavenging free radicals • Antioxidation • Mineral chelation • Activating zntioxidant enzymes • Reducing alpha-tocopherol radicals •

Figure 1. The basic chemical structure of flavonoids

Inhibiting oxidases All of these crucial functions can help improve metabolic pro- cesses, production and growth performance.

Healthy inflammation response Inflammatory syndromes may be evident in what appear to be normal rearing conditions. Studies have shown that unhealthy inflammatory responses may be linked to the use of unsaturat- ed oils as energy sources in pig and poultry feed, especially when vegetable sources are also used. Omega-6 fatty acids are pro-inflammatory and, while high levels of Omega-3 rich oils can act in the same way, they normally reduce inflammation.

While inflammation is a normal reaction when microbial tox- ins or toxic chemicals from feed come into contact with sev- eral body tissues, inflammation can also be an indicator of a number of serious ailments, including problems with joints, eyes, weight, heart, respiratory and digestive health. Polyphe- nols interrupt the metabolic pathways leading to increased cytokine expression, reducing the severity of inflammation and helping to maintain a healthy inflammatory response.

Maintaining healthy gut status The intestines typically consume 20% of the energy and 15% of the protein from feed. Intestinal cells are completely shed every 96 hours, so the intestine replaces all cells twice a week. Studies have demonstrated that selected polyphenols have the ability to alter gut microflora, increasing its diversity and reducing potential pathogens. Polyphenols and associated metabolites may affect the intestinal ecology and modulate microbiota6. Several phenolic compounds have been identi- fied as potential antimicrobial agents with bacteriostatic or bactericidal activity. These could also act as inhibitors of

bacteria that cause infection within the cells of the intestinal and urinary tracts, suggesting that some phenolic com- pounds may have the potential for application as antimicro- bial agents. Most nutrition practices today seek to improve gut structure. The field of intestinal health is one of the most active in modern animal nutrition and this is mainly because a healthy intestine means higher efficiency in feed processing and nutrient absorption, and can greatly improve overall ani- mal health, growth and production economics. This is espe- cially relevant for fast-growing meat species. Many factors al- ter gut integrity and the barrier factor in the intestine lining. Interaction with xenobiotics or endotoxins may damage a critical structure known as tight junction. This structure regu- lates the paracellular absorption route. When it is damaged, it opens the passage up to toxins and micro-organisms that in- vade the connective tissue that lines the intestine. There, in- flammatory and immune responses consume protein and en- ergy and derive nutrients otherwise available for growth from these local reactions.

Improving tight junction permeability creates conditions fa- vorable for enhanced growth performance. Results from our research show that providing selected dietary polyphenols to growing chickens may result in an increase of tight junc- tion proteins (claudins, occludin and zonula occludens) rela- tive to the abundance of same proteins detected among control birds. Another effect of the use of polyphenols is de- creased apoptosis (cell death). Apoptosis is an internal pro- cess that works to remove intestinal cells. Decreased apop- totic rates means that less energy and protein is required for cell replacement, and more is left for animal development. All in all, this represetns a net benefit for the animal − and for the producer. Research has shown that polyphenols can be extremely valuable in animal nutrition and health. When considering the use of polyphenols as feed additives, there are important considerations. Efficacy is based on selecting the right ingredient sources, concentration and potential ad- ditive or synergistic interactions with other ingredients. Look for quality polyphenol sources from reputable suppliers with an emphasis on research and scientific validation.

References are available from the author on request ▶ ALL ABOUT FEED | Volume 28, No. 8, 2020 19


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