Related Experiment Video
Updated: Aug 17, 2026
The Effect of the Application of Thyme Essential Oil on Microbial Load During Meat Drying
Published on: March 14, 2018
A microencapsulated feed additive containing organic acids, thymol, and vanillin increases in vitro functional
Christina L Swaggerty1, Haiqi He1, Kenneth J Genovese1
1U.S. Department of Agriculture, Agricultural Research Service, Southern Plains Agricultural Research Center, College Station, TX 77845, USA.
Insights
Supplementing young broiler chicks
Area of Science:
- Poultry Science
- Immunology
- Animal Nutrition
Background:
- Young chicks have underdeveloped immune systems, making them susceptible to pathogens.
- Early-life nutrition is critical for developing a robust immune response in poultry.
- Feed additives can modulate the immune system in young birds.
Purpose of the Study:
- To investigate the impact of a microencapsulated feed additive on peripheral blood leukocyte (PBL) function in broiler chicks.
- To determine if a blend of citric acid, sorbic acid, thymol, and vanillin enhances immune cell activity in young poultry.
Main Methods:
- Day-old broiler chicks were fed either a control diet or a diet supplemented with a microencapsulated additive (citric acid, sorbic acid, thymol, vanillin).
- Peripheral blood leukocytes (heterophils and monocytes) were isolated from chicks at 4 days of age.
- Immune functions assessed included heterophil degranulation, oxidative burst, nitric oxide production in monocytes, and cytokine/chemokine mRNA expression.
Main Results:
- Supplementation significantly enhanced heterophil degranulation and oxidative burst responses.
- Monocytes from supplemented chicks exhibited significantly higher nitric oxide production.
- Key cytokine mRNA expression (IL10, IL1β, CXCL8) in heterophils was upregulated, while monocyte IL10 mRNA expression decreased.
Conclusions:
- Supplementation with the microencapsulated blend of citric and sorbic acids, thymol, and vanillin improved in vitro peripheral blood leukocyte functions in broiler chicks.
- The additive acts as an immune-modulator, potentially enhancing the immune efficiency of young chicks.
- This feed additive shows promise for supporting the immature immune system of broiler chicks.
Abstract:
During the first week after hatch, young chicks are vulnerable to pathogens as the immune system is not fully developed. The objectives of this study were to determine if supplementing the starter diet with a microencapsulated feed additive containing citric and sorbic acids, thymol, and vanillin affects in vitro functional activity of peripheral blood leukocytes (PBLs). Day-old chicks (n = 800) were assigned to either a control diet (0 g/metric ton [MT]) or a diet supplemented with 500 g/MT of the microencapsulated additive. At 4 D of age, peripheral blood was collected (100 birds per treatment), and heterophils and monocytes isolated (n = 4). Heterophils were assayed for the ability to undergo degranulation and production of an oxidative burst response while nitric oxide production was measured in monocytes. Select cytokine and chemokine mRNA expression levels were also determined. Statistical analysis was performed using Student t test comparing the supplemented diet to the control (P ≤ 0.05). Heterophils isolated from chicks fed the microencapsulated citric and sorbic acids, thymol, and vanillin had higher (P ≤ 0.05) levels of degranulation and oxidative burst responses than those isolated from chicks on the control diet. Heterophils from the supplemented chicks also had greater (P ≤ 0.05) expression of IL10, IL1β, and CXCL8 mRNA than those from control-fed chicks. Similarly, nitric oxide production was significantly (P ≤ 0.05) higher in monocytes isolated from birds fed the supplement. The cytokine and chemokine profile in monocytes from the supplement-fed chicks showed a significant (P ≤ 0.05) drop in IL10 mRNA expression while IL1β, IL4, and CXCL8 were unchanged. In conclusion, 4 D of supplementation with a microencapsulated blend made up of citric and sorbic acids, thymol, and vanillin enhanced the in vitro PBL functions of degranulation, oxidative burst, and nitric oxide production compared with the control diet. Collectively, the data suggest feeding broiler chicks a diet supplemented with a microencapsulated blend of citric and sorbic acids, thymol, and vanillin may prime key immune cells making them more functionally efficient and acts as an immune-modulator to boost the inefficient and undeveloped immune system of young chicks.
