Protected organic acids and essential oils for broilers raised under field conditions: Intestinal health biomarkers and cecal microbiota

Authors: BORTOLUZZI, CRISTIANO - Jefo Nutrition Canada; LAHAYE, LUDOVIC - Jefo Nutrition Canada; OXFORD, JARRED - Jefo Nutrition Canada; DETZLER, DEREK - Jefo Nutrition Canada; EYNG, CINTHIA - Western Paraná State University; BARBIERI, NICOLLE - University Of Georgia; SANTIN, ELIZABETH - Jefo Nutrition Canada; Kogut, Michael - Mike

Submitted to: Frontiers in Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/7/2021
Publication Date: 10/25/2021
Citation: Bortoluzzi, C., Lahaye, L., Oxford, J., Detzler, D., Eyng, C., Barbieri, N.L., Santin, E., Kogut, M.H. 2021. Protected organic acids and essential oils for broilers raised under field conditions: Intestinal health biomarkers and cecal microbiota. Frontiers in Physiology. 12. Article 722339. https://doi.org/10.3389/fphys.2021.722339.
DOI: https://doi.org/10.3389/fphys.2021.722339

Interpretive Summary: Consumer demand has resulted in chicken producers removing antibiotics to be used as growth promoters in chicken feed. Therefore, it is important to find inexpensive, natural feed supplements as alternatives to antibiotics to help chickens stay healthy and grow. The objective of this experiment was to add natural materials made from plants to chicken feed and compare their ability to improve the gut health of chickens raised in a commercial chicken house under normal environmental conditions when compared to chickens provided an antibiotic growth promoter. The results showed that the plant-based additives improved the gut health, reduced inflammation, and maintained the composition and diversity of the good bacteria in the gut when compared to the antibiotic-fed birds. These results are important to the poultry industry because it shows that natural plant-based feed additives can be used as alternatives to antibiotics that can improve the health, lives, and growth of chickens in the normal chicken house environment.

Technical Abstract: The objective of the present study was to evaluate the effect of protected organic acids and essential oils [P(OA+EO)] on the intestinal health of broiler chickens raised under field conditions. The study was conducted on 4 commercial farms. Each farm consisted of 4 barns: 2 barns under a control diet and 2 tested barns supplemented with P (OA+EO), totaling 16 barns (8 control and 8 under P(OA+EO). The control group was supplemented with antibiotic growth promoters (AGP; BMD (50 g/ton) during starter, grower and finisher 2, and flavomycin (2 g/ton) during finisher 3). The tested group was supplemented with 636, 636, 454, and 454 g/ton of P(OA+EO) during starter, grower, and finisher 2 and 3, respectively. Both groups were supplemented with narasin (63 and 72 g/ton, for grower and finisher 2, respectively) and vaccinated against coccidiosis (ADVENT®) at the hatchery. A total of 80 birds were necropsied (40/treatment; 20/farm; 5/barn) to collect blood for cytokine array analysis and calprotectin (CALP) concentration, jejunal tissue for I See Inside® (ISI) analysis, and cecal contents to analyze the microbiota and the frequency of antimicrobial resistant (AMR) genes. The data was submitted to ANOVA (P<0.05) or Kruskal-Wallis’ test and the frequency of AMR genes was analyzed by Chi-Square test (P<0.05). It was observed that the supplementation of P(OA+EO) reduced (P<0.05) the ISI scores related to intestinal inflammation, such as the infiltration of inflammatory cells in the epithelium and lamina propria and tended (P=0.09), to reduce the serum concentration of CALP. The supplementation of P(OA+EO) reduced the serum concentration of IL-12 (P=0.0001), IL-16 (P=0.001), and Pentraxin-3 (P=0.04). Additionally, P(OA+EO) maintained a cecal microbiota content similar to birds receiving AGP, without significant changes in its diversity and composition. The removal of AGP and inclusion of P(OA+EO) reduced (P<0.05) the frequency of five AMR genes related to gentamicin (3 genes), tetracycline (1 gene), and aminoglycoside (1 gene). Overall, the inclusion of P(OA+EO) and removal of AGP in the diets of commercially raised broiler chickens beneficially changed the phenotype of the jejunum as shown by the lowered ISI scores which characterizes an improved intestinal health. Furthermore, P(OA+EO) significantly reduced the serum concentration of several inflammatory biomarkers, while maintaining the diversity and composition of the cecal microbiota similar to AGP fed chickens and reducing the prevalence of AMR genes. It can be concluded that P(OA+EO) improved the intestinal mucosa health, maintaining the balance of the microbiota and reducing AMR genes, which provides practical advantages for broilers raised without antibiotics.