In the post-antibiotic era, novel non-antibiotic feed additives have become increasingly important for controlling poultry diseases and improving the intestinal health and performance of commercial poultry. The goal of these additives is to optimize host immunity, reduce gut damage and reduce the presence of pathogens and anti-nutritional factors that compromise animal health.
Through metabolomics, potential biomarkers associated with gut health and growth performance in chickens have been identified, and these biomarkers may help facilitate the development of microbiota-targeted precision nutrition for chickens and other animals.
Following up on a prior study that discovered the beneficial effects of feeding two strains of Bacillus subtilis to broiler chickens, a group of researchers with the U.S. Department of Agriculture-Agricultural Research Service and Arm & Hammer Animal & Food Production determined through a metabolomics study that the amino acid metabolite carnosine showed the highest relative increase of identified metabolites.
Carnosine, a dipeptide of beta-alanine and histidine, is widely distributed in various tissues of animals including chickens, which suggests an important role in cellular functions. The researchers pointed to studies indicating that carnosine exhibits anti-inflammatory and antioxidant properties, improves intestinal barrier integrity and modulates the host immune system.
They hypothesized that dietary carnosine supplementation in chickens infected with Eimeria maxima could alter the inflammatory response, permeability and nutrient transport in the intestine, leading to changes to bird growth.
They conducted two studies: the first assessed the effects of carnosine on the immune response and gut integrity in vitro, while the second evaluated the impact of dietary carnosine on growth, immunity, gut health and nutrient absorption in broiler chickens infected with E. maxima.
Their findings were recently published online here.
In the in vitro study, the researchers observed that carnosine was not involved in the regulation of tight junction proteins but was involved in the inflammatory response. They also found that carnosine did not have the ability to directly eliminate E. maxima sporozoites.
In the in vivo study, the researchers determined that dietary carnosine supplementation facilitated the recovery process following E. maxima infection and enhanced average daily gain in broilers.
The researchers observed E. maxima infection induced an inflammatory response by increasing all measured cytokines except IL-6, but dietary carnosine supplementation decreased the inflammatory response by suppression gene expression of a few cytokines that had been increased due to the Eimeria infection.
For nutrient transporters in the jejunum, a tendency was observed for the gene expression of some transporters to decrease; however, carnosine supplementation may influence the damaged transporters by facilitating their recovery.
What does this mean for producers?
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Dietary carnosine did not demonstrate a direct anti-coccidial effect buy may mitigate inflammation and other negative effects of coccidial infections on growth performance of chickens.
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Carnosine may help preserve the intestinal integrity of chickens.
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Beneficial gut metabolites such as carnosine show potential as novel alternatives to growth-promoting antibiotics to mitigate the negative effects of coccidiosis in young broiler chickens.
The full paper, “The effect of gut microbiota-derived carnosine on mucosal integrity and immunity in broiler chickens challenged with Eimeria maxima,” can be found in Poultry Science and online here.
DOI: 10.1016/j.psj.2024.103837
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