A blend of microencapsulated organic acids and botanicals reduces necrotic enteritis via specific signaling pathways in broilers

Authors: Swaggerty, Christina - Christi; Byrd Ii, James - Allen; ARSENAULT, RYAN - University Of Delaware; PERRY, FAMATTA - University Of Delaware; JOHNSON, CASEY - University Of Delaware; Genovese, Kenneth - Ken; He, Louis; Kogut, Michael - Mike; PIVA, ANDREA - University Of Bologna, Italy; GRILLI, ESTER - University Of Bologna, Italy

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/19/2022
Publication Date: 4/1/2022
Citation: Swaggerty, C.L., Byrd II, J.A., Arsenault, R.J., Perry, F., Johnson, C.N., Genovese, K.J., He, H., Kogut, M.H., Piva, A., Grilli, E. 2022. A blend of microencapsulated organic acids and botanicals reduces necrotic enteritis via specific signaling pathways in broilers. Poultry Science. 101(4). Article 101753. https://doi.org/10.1016/j.psj.2022.101753.
DOI: https://doi.org/10.1016/j.psj.2022.101753

Interpretive Summary: The poultry industry is using fewer antibiotics to grow chickens, so alternative products to take their place are needed. Removal of antibiotics has led to increased disease outbreaks throughout the poultry industry, including necrotic enteritis (NE), a severe disease which leads to both animal welfare concerns and potential food safety issues. NE is caused by the bacterium Clostridium perfringens (CP), the fourth leading cause of bacterial-related foodborne illness. One approach to replace antibiotics is to use natural products as feed additives. The objective of this project was to determine if an encapsulated feed additive (AviPlus®P) could serve as an antibiotic alternative and reduce NE and CP in chickens. We also wanted to know how the antibiotic alternative impacted the chickens. Our laboratory has designed a chicken array so we can understand how the feed additive is working. The array is a tool that allows us to determine specific immune and metabolic pathways that are activated in the bird so we can monitor the health-status (immune) and growth performance (metabolic) in chickens. Baby chicks were assigned to a control or supplemented diet and evaluated in a NE challenge model. On day 21, birds were weighed and terminated, and we looked for NE lesions in the gut and took a piece of tissue that was analyzed with the array. Fewer chicks died in the supplemented group compared to those on the control diet. There were also less severe gut lesions in supplemented birds compared to controls, and the supplement-fed birds maintained their weight better than those on the control diet. Using special computer programs, we showed specific immune pathways were highly activated in the chicks on the diet supplemented with the antibiotic alternative. The antibiotic alternative feed additive activated important immune responses and protected the chickens from severe disease, thereby improving animal health.

Technical Abstract: The objective was to evaluate the efficacy of a microencapsulated blend of organic (25 % citric and 16.7% sorbic) acids and botanicals (1.7% thymol and 1% vanillin [AviPlus®P]) to reduce clinical necrotic enteritis (NE) and determine the signaling pathways associated with any changes. Day-of-hatch by-product breeder chicks were randomly assigned to a control (0) or supplemented (500 g/MT) diet (n=23-26) and evaluated in a NE challenge model (n=3). Birds were administered 2X cocci vaccine on d14 and challenged with a cocktail of Clostridium perfringens strains (107) on d17-19. On d20-21, birds were weighed, euthanized, and scored for NE lesions. Jejunum was collected for kinome analysis using an immuno-metabolism peptide array (n=5; 15/treatment) to compare tissue from supplement-fed birds to controls. Mortality, C. perfringens recovered, and weight were analyzed using the Student’s t-test. Lesion scores were analyzed using F-test two-sample for variances (P<0.05). The kinome data was analyzed using PIIKA2 peptide array analysis software and fold-change between control and treated groups determined. The P-value was calculated by conducting a one-sided paired t-test between treatment and control values for a given peptide. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was performed by uploading significant (P<0.05) peptides to the Search Tool for the Retrieval of Interacting Genes database (STRING version 11.0). Mortality in the supplemented group was 47.4% and 70.7% in controls (P=0.004). Lesions scores were lower (P=0.006) in supplemented birds (2.47) compared to controls (3.3). Supplement-fed birds tended (P=0.19) to be heavier (848.6g) than controls (796.2g). Kinome analysis showed that T cell receptor, TNF ,and NF-kB signaling pathways contributed to the improvements seen in the supplement-fed birds. The following peptides were significant (P<0.05) in all three immune-related pathways: CHUK, MAP3K14, MAP3K7, and NFKB1 indicating their importance. In conclusion, the addition of a microencapsulated blend of organic acids and botanicals to a broiler diet reduced the clinical signs of NE that was mediated by specific immune-related pathways including the T cell receptor, TNF, and NF-kB signaling pathways.