Table 7.

Application of mixtures of phytogenics and organic acids with major physiological responses in poultry.

Mixture of OA+EO	Study Design	Main Findings	Reference
Citric (25%) and sorbic (16.7%) acids, thymol (1.7%), and vanillin (1.0%)	Type: male breeder chickens Dose: 500 g/metric ton diet Form: microencapsulated Duration: 15 days Conditions: without challenge	-Increased Lactobacilliaceae, Clostridiaceae and Ruminococcaceae abundance -Decreased Staphylococcaceae,	[185]
Thyme (4%), carvacrol (4%), hexanoic acid (0.5%), benzoic acid (3.5%) and butyric acid (0.5%)	Type: male Arbor Acres broiler chickens Dose: 500 mg/kg diet Form: Encapsulated Duration: 42 days Conditions: Eimeria spp. and Clostridium perfringens	-Improved FCR -Higher villus height and villus height/crypt depth ratio. -Reduced intestinal C. perfringens counts, liver C. perfringens carriage, and gut lesion scores. -Reduced serum fluorescein isothiocyanate dextran (FITC-D) concentrations. -Upregulated claudin-1, IGF-2 and A20 mRNA expression. -Downregulated TRAF-6, TNFSF15 and TOLLIP mRNA levels	[181]
Citric (25%, as fed) and sorbic acids (16.7%, as fed), thymol (1.7%, as fed) and vanillin (1%, as fed)	Type: Male Ross 308 broiler chickens Dose: 5 g/kg diet Form: Encapsulated Duration: 47 days Conditions: without challenge	-Improved growth performances -Improved gut morphology -Microbial control against Clostridium perfringens, Enterobacteriaceae, Enterococci and Mesophilic bacteria	[186]
Fumaric, sorbic, malic, and citric acids, thymol, vanillin, and eugenol	Type: Cobb 500 male broilers Dose: 300 g/t diet Form: Protected Duration: 42 days Conditions: Eimeria spp. and Clostridium perfringens	-Greater body weight gain -Higher apparent ileal nutrient and energy digestibility -Improved intestinal integrity with lower blood fluorescein isothiocyanate-dextran concentration -Improved intestinal macroscopic and histologic alterations -Greater expression of MUC2, CLDN1, and OCLN genes	[182]
Citric andsorbic acids, thymol, and vanillin	Type: By-product breeder chicks Dose: 500 g/metric ton diet Form: Microencapsulated Duration: 4 days Conditions: Without challenge	-Enhanced in vitro functional activity of peripheral blood leukocytes (degranulation, oxidative burst, and nitric oxide production)	[187]
Sorbic acid (200 g/kg), fumaric acid (200 g/kg), and thymol (100 g/kg)	Type: Roman laying hens Dose: 150 and 300 mg/kg diet Form: Encapsulated Duration: 21–30 weeks Conditions: Without challenge	-Increased laying rate with 150 mg/kg. -A linear increase in ileal villus height. -Increased mRNA relative expression of aminopeptidase, sodium-glucose cotransporter 1, and Na+-independent neutral amino acid transporter in duodenum and glucose transporter 2 in jejunum with 300 mg/kg. -Higher mRNA relative expression ofmucin-2 in ileum with 300 mg/kg. -Linear decrease of the secretory immunoglobulin in ileum A.	[188]