Cinnamon: a natural feed additive for broiler health

Previously, antibiotic growth promoters (AGPs) were used to control gastrointestinal pathogens and reduce the effects of stressors on bowel function.

• However, growing consumer awareness towards the adverse effects of antibiotics on human health, coupled with increasing bacterial resistance and food safety concerns, have led to bans on antibiotic use in poultry production.

Phytogenic additives (PA) have emerged as alternatives to AGPs and have great potential within the poultry industry. For example, it has been shown that under heat stress conditions in poultry, these can:

• Enhance immune function
• Exert beneficial effects on health performance
• Reduce stress response (Rashid y col., 2020).

The natural antioxidants found in many PAs have also been found to be effective in extending the shelf life of poultry meat, as well as improving its quality and acceptability.

Phytochemicals from herbs and spices have attracted special attention as alternatives to AGPs due to their beneficial properties:

• Natural
• Reduced toxicity
• Free of chemical residues
• Easy-availability

Natural plant products have been found to have beneficial effects, such as:

• Increased secretion of digestive enzymes
• Immunostimulant
• Bactericide
• Antiviral
• Antioxidant

Cinnamon is considered one of the most potent PAs, and has great potential for poultry use.

The effects of cinnamon on the intestinal health of birds are shown in Figure 1.

Figura 1.Effect of cinnamon on poultry intestinal health

Source: Taken from  Akhtar Ali y col., 2021

Cinnamon

Cinnamon contains [register]several bioactive compounds including natural antioxidants, antimicrobials and anti-inflammatory components. Amongst which there are: volatile oils, flavonoids, curcuminoids, coumarins, tannins, alkaloids, xanthones, terpenoids, phenols and others (Liyanage et al., 2021).

• The concentration of volatile compounds in cinnamon essential oil (CEO) mainly depends on the part of the plant (leaves, bark, root, stem) from which it is extracted.

 Cinnamaldehyde is the main CEO compound that is extracted from the bark. Meanwhile eugenol is the main compound  extracted from the leaves.

The main bioactive compounds in cinnamon are cinnamaldehyde, cinnamate, and cinnamic acid, all of which play vital roles in various biological activities (Namazi et al., 2019).

The different essential oils that have been reported in cinnamon include:

• trans-cinnamaldehyde
• eugenol
• cinnamyl acetate
• L-borneol
• L-bornyl acetate
• β-cariofileno
• caryophyllene oxide
• E-nerolidol
• α-thujene
• α-cubebene
• terpinolene
• α-terpine

Cinnamon is high in polyphenols and anthocyanidins (procyanidins A and B).

Poultry gut health

The intestinal ecosystem plays a vital role in removing toxins and infectious agents from  the intestinal tract of birds. Many factors influence the gut microbial ecosystem, including:

• Feed additives (phytobiotics, prebiotics, probiotics, feed enzymes, organic acids, etc.)
•  Feed composition
• Genetics
• Heat stress
• Feeding practices within the poultry farm, amongst others.

The intestinal ecosystem of poultry consists of bacteria, protozoa and fungi in varying proportions. The concentration of microbiota varies along the intestinal tract, having greater numbers in the distal segments. The intestinal epithelium has tight junctions between cells that prevent the colonization of microorganisms while also participating in cell signaling.

Cinnamon use in poultry feed

Cinnamon is one of the PAs approved by the U.S. Food and Drug Administration for its inclusion in poultry feed.

The bioactive compounds in cinnamon have potent anti-inflammatory, antimicrobial and antioxidant properties with free radical scavenging actions and strong inhibitory effects on nitric oxide (NO) production by suppressing NFκβ activity (Zhu et al., 2020).

At the same time, the bioactive compounds in cinnamon can disrupt the growth of pathogenic microbes and stimulate the growth of commensal bacteria in the intestinal tract of poultry (Wenk, 2003).

Impact of cinnamon on nutrient digestibility

Cinnamaldehyde may also improve nutrient absorption by protecting gut morphology and integrity:

Cinnamaldehyde supplementation in the diet of broilers increased villus height in the duodenum and jejunum with an associated increase in nutrient absorption and digestion efficiency (Redondo et al., 2014).

Recent studies suggested that tannins (water-soluble phenolic compounds)found in cinnamon have a significant impact on poultry health and nutrition, as they can precipitate proteins in the gut (Cross et al., 2011).

• The apparent ileal digestibility of crude fat and amino acids (histidine, lysine, serine, phenylalanine, asparagine, and threonine) was significantly higher in cinnamaldehyde-supplemented groups (Jamroz et al., 2003).

Effects of cinnamon on intestinal microbiota 

It is likely that desired optimal health and performance in birds can be achieved by modulating the gut microbiota.

• The cecum is densely populated by a number of bacteria that are primarily responsible for the fermentation of nutrients that are not absorbed in the ileum (Lee et al., 2017).

Dietary cinnamon promoted the growth of beneficial bacteria while reducing pathogenic bacterial load compared to control groups (Rashid et al., 2020). They found that dietary cinnamon increased the growth of  Lactobacillus spp. while inhibiting Campylobacter spp. and E. coli in the ileum and cecum of poultry.

The production of SCFAs is attributed to the fermentation of Lactobacillus spp. which are responsible for the maintenance of the intestinal ecosystem and the prevention of pH-sensitive pathogenic bacteria.

The bioactive compounds in cinnamon have potential antimicrobial activities against

• Enterococcus faecalis
• Vibrio parahaemolyticus
• Pseudomonas aeruginosa
• Salmonella spp.
• Klebsiella pneumoniae
• Staphylococcus epidermis
• Staphylococcus aureus
• E. coli

Anthocyanins suppress the growth of pathogenic bacteria and  improve the functionality of bird organs and can potentially enhance heat stress (Iqbal et al., 2020).

Flavonoids, including those found in cinnamon, act as antimicrobial agents in the gut of birds (Iqbal et al., 2020).

Research groups found that cinnamon bark contains high concentrations of tannins. Tannins increase Firmicutes  and Bacteroides in the  cecum of broilers and support Lactobacillus growth  by inducing iron-poor environments within the gut (Shan et al., 2007).

The ethanolic extract of cinnamon has strong antimicrobial activity against Salmonella aureus strains as reported by Bonilla and Sobral (2017).

Conclusions

The inclusion of cinnamon in poultry feed as a phytogenic additive has beneficial effects on nutrient digestibility, hypocholesterolemia, blood biochemistry profiles, gene expression, immunity and, in particular, on gut health. Alleviating the impacts of disease and environmental stressors.

Cinnamon supplementation in poultry feed mitigates the stress response by suppressing the NF-κβ pathway and increasing the expression of anti-inflammatory cytokines.

This review demonstrates that cinnamon can be used as a PA, in order to improve food safety, health and economic parameters in the poultry industry.

Source: Akhtar Ali y col., 2021

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