Lauric acid glycerides boost immune response to IB virus

A trial was conducted with broilers that were vaccinated or not with an attenuated infectious bronchitis virus (IBV). Chickens that received dietary glycerides of lauric acid (GLA) on top of vaccination displayed stronger natural defense mechanisms. Their primary immune response was more pronounced, as shown by a higher anti-IBV titer. In addition, their cellular immune response was more effective.

WHY INVESTIGATING GLYCERIDES OF LAURIC ACID?
The poultry industry continually seeks innovative strategies to enhance the health and productivity of birds. Dietary supplements that can strengthen the natural defense systems of birds are receiving increased attention, especially in today’s poultry production landscape, where minimizing disease pressure is of pivotal importance to increase animal performance and profitability.

Lauric acid is a medium-chain fatty acid that has been described to have unique antimicrobial and antiviral activities in vitro. Esterifying lauric acid into glycerides of lauric acid (GLA) magnifies its biological activity. Moreover, a GLA product (FRA^® C12) was already demonstrated to stimulate the secondary humoral immune response to a booster infectious bronchitis virus (IBV) vaccine, as indicated by increased anti-IBV titer values in the serum of 42-day-old broilers (De Gussem et al., 2021).

Following these results, we wanted to explore in more depth the immune reactions prior to this secondary response. More specifically, we investigated the effect of the GLA product on the primary humoral response, as well as the adaptive cellular immunity in more details, and described the results in a recently published scientific article (Mellouk et al., 2024).

ENHANCEMENT OF THE PRIMARY HUMORAL RESPONSE…
A total of 200 one-day-old male Ross 308 broilers were divided over 3 experimental groups, with 8 replicates per group: a control group receiving no vaccination and a dietary supplementation of GLA (V^–GLA⁺), a vaccinated non-supplemented control group (V⁺GLA^–) and a group that received both the vaccination and the GLA (V⁺GLA⁺).

We first analyzed the serum of day 7-old birds for IBV-specific antibodies. In the V⁺GLA⁺ group, significantly higher anti-IBV titer values were found (Fig. 1). This finding is of utmost importance, as a higher number of antibodies against IBV at this early age is correlated with a higher protection level and lower mortality after IBV infection later in life (De Wit et al., 2010).

…AND THE CELLULAR IMMUNE RESPONSE
In a later stage, at day 28, we collected spleens from birds from the different treatment groups to look at the splenocytes, mainly consisting of lymphocytes. Surprisingly, a lower amount of splenocytes was found in birds from the V⁺GLA⁺group. However, no differences were detected in the basal levels of cytokines secreted by T lymphocytes, nor in the levels of peripheral blood mononuclear cells. This suggests that the basal activity of splenocytes or the evasion of patrolling effector cells in the blood was not negatively affected.

In a next step, we incubated the splenocytes for 24 hours with Concanavalin A or with an IBV peptide, to measure T cell reactivity to a general or specific stimulus, respectively. Using an ELISpot assay, we could detect more and larger IFNγ-reaction spots in the cells derived from the V⁺GLA⁺ group (Fig. 2), which means that the GLA product was able to increase the proportion and reactivity of cell subsets like T helper 1 cells (T_H1) and cytotoxic T lymphocytes (CTL) in vaccinated birds. Activated CTL cells are crucial to clean up infected cells, while T_H1 cells can increase the pathogen-destroying activity of macrophages.

CONCLUSION
In summary, the tested GLA represents a promising additive for promoting health in broilers. By stimulating the birds’ natural defense mechanisms, the product is expected to improve vaccination efficiency as well as to increase resilience against viral and other pathogenic challenges.

As research continues to uncover the full potential of lauric acid-based products such as GLA, we can expect knowledge to increase on how poultry producers can optimally apply these compounds to achieve healthier, more resilient birds and more sustainable and efficient poultry production systems. Hence, FRA^® C12 Dry is an important part of Adisseo’s recent program, Secure Performance, in which we aim to enhance poultry resilience towards pathogens.

About Tim Goossens
Tim Goossens obtained a Master’s degree in Biotechnology at Ghent University (Belgium), and a Ph.D. in Biomedical Sciences at the KU Leuven (Belgium). In 2010, he joined Nutriad, first as an R&D Engineer, later as Business Development Manager for a product range dedicated to gut health in production animals. Since 2019, he is Global Scientific & Technical Manager at Adisseo, providing support to the Health by Nutrition portfolio. This product category includes probiotics, short- and medium-chain fatty-based additives, and other products related to animal health and performance.

About Olga Lemâle
Olga Lemâle obtained a Master’s degree in animal sciences, with specialization in animal nutrition at Wageningen University (the Netherlands). In 2015, she joined FRAmelco, as head of R&D. In 2023, she became Global Scientific & Technical Manager at Adisseo, providing support to the Health by Nutrition portfolio. This product category includes probiotics, short- and medium-chain fatty-based additives, and other products related to animal health and performance.

About Amine Mellouk
Amine Mellouk has a Master’s degree in Genetics from USTO, Algeria, a Master’s degree in cell signaling and a Ph.D in immunology from the University of Paris-Saclay-ENS Cachan, France. His research work treated the etiology and therapy developments for systemic autoimmune diseases at INSERM and SATT networks. He joined Adisseo in September 2021 as Science Manager, Immunology, for the Health by Nutrition research team. He brings his expertise in immunology to support, create and execute the research strategies to understand and improve animal resilience through nutritional solutions.

About Jessika Consuegra
Jessika Consuegra holds a Master’s in Biotech Innovation from UFMG, Brazil, and a Ph.D. in Microbial EcoEvo from Grenoble University, France. Her scientific work has consistently highlighted the critical influence of microbiota on animals’ health and nutrition, which earned her the ‘Rising Talents’ award from the L’Oréal-UNESCO For Women in Science Foundation. Consuegra joined Adisseo in September 2021 as the Scientific Leader of the Health by Nutrition Team. In this role, she is responsible for building new research programs aligned with business needs to develop new solutions and knowledge in the field of animal health and resilience modulation through nutrition.