What happens when you supplement the diet of broiler chickens with extracts of cucumber and citrus?

by Aurelia Chaise

Discover the Project 3 of the MANNA network. You will find out that novel plant extracts could be an alternative to the use of antibiotics.

The European Joint Doctorate in Molecular Animal Nutrition (MANNA) is an EU network whose mission is to provide a double doctorate-level training programme, valid throughout Europe, on innovative technologies applied to animal science and nutrition. The MANNA Joint Doctoral project is a Marie Skłodowska-Curie Innovative Training Network funded by the European Commission under the Horizon 2020 Programme. This is the fourth of a series of articles on the MANNA doctorate, through which we will discover in detail its projects and introducing the related Early Stage Researchers (ESRs).


Who I am

I’m Francesca Riva and I was born in Italy, where in 2015 I graduated in Veterinary Biotechnology at the University of Milan after a fellowship period in the laboratory of parasitology. Continuing my studies, I obtained an MSc in Veterinary Biotechnology Sciences at the same university, where I discovered my greatest passion in Omic technologies. In 2016, I was selected for an Erasmus+ international exchange programme and I had the opportunity to acquire seven months of practical experience at the Department of Veterinary Molecular Genetics of the Autonomous University of Barcelona (Spain), where I developed my final dissertation project. In 2017, I attended a master course in “clinical research” at the Mario Negri Institute for Pharmacological Research in order to deepen my knowledge on different aspects related to the planning of a clinical trial. When I discovered the MANNA project, I was particularly keen to join it as its research field is an excellent match for my academic background and my passion for Omics.

I am the ESR of Project 3 of the MANNA network, and I am working under the supervision of Maureen Bain (University of Glasgow), Vladimir Mrljak (University of Zagreb) and Geert Bruggerman (Nutrition Science, Belgium) on the project titled “Effect of novel plant extracts on gut microbiota, metabolome and immune system of broiler chickens pre and post E.coli LPS challenge.”


Project overview

The poultry industry has grown significantly over the last few decades due to genetic improvements and intensive production methods, and it is predicted it will continue to grow. Nowadays, the primary aim is to maximize production; however, chickens are raised in intensive farming conditions with a high risk of epidemic outbreaks. Prevention and control of poultry diseases have led during the last decades to a substantial increase in the prophylactic use of antibiotics. However, any time antibiotics are used, they can cause side effects and lead to antibiotic resistance. For this reason, antibiotics were outlawed in poultry and pig diets around the world, beginning in Sweden in 1986. Since then, much research has been carried out on natural agents with similar beneficial effects as antimicrobial growth promoters and antimicrobial substances. Probiotics, prebiotics, enzymes, medium-chain fatty acids, essential oils and vitamins are already used as alternatives, and in recent years plant extracts have attracted the attention of the research community for their promising properties. However, the active compounds of plant extracts and their mechanism of action is not well known, so, the identification and standardisation of their beneficial chemical and/or biological molecules is a major challenge for animal industries. Among the variety of novel plant extracts, citrus and cucumber extracts have been chosen to be tested in my MSCA PhD project, thanks to their availability, cost, active molecules (i.e. pectin, flavonoids, limonene, carotenoids, polyphenols, dietary fibres, essential oils) and the existing evidence of beneficial effects on poultry. Having a full picture of how these novel dietary ingredients interact with the bird’s microbiota[1], metabolism and immune system could develop new dietary plans that would enhance bird growth, maximise feed efficiency and protect the birds from diseases.


Therefore, the main aim of my study is to test the hypothesis that supplementing the feed of broiler chickens with citrus or cucumber extracts can improve gut health through the modulatory effects of the microbiota, metabolome2 and immune system under standard and E. coli lipopolysaccharide (LPS) challenge conditions, LPS being an endotoxin able to stimulate the innate immune response. To investigate this, two in vivo trials have been carried out at Cochno farm, in Glasgow, to explore if each dietary supplement influences the:

•           Growth performance of healthy chickens (zootechnical data)

•           Intestinal microbiota of healthy chickens

•           Gut morphology of healthy chickens (histology-morphometric measurements)

•           Immune system of challenged chickens (acute-phase proteins investigation)

•           Metabolome of challenged chickens (metabolomics study)


My project so far

During my first year at the University of Glasgow, I ran two in vivo trials on broiler chickens. The basal diet used in the trials was formulated and prepared at the Nuscience company in Belgium, while the experimental extracts (citrus and cucumber) were blended with the control diet directly at Cochno farm in Scotland. During the trials, various biological samples (e.g. tissue and blood) and zootechnical data were collected to evaluate the growth performance of chickens, based on different dietary regiments (control, citrus or cucumber).

Samples collected from healthy chickens were used to study the microbiota and evaluate the microbial population at gut level of healthy chickens during a period of 28 days. The connection between the status of intestinal villi and the microbiota, as influenced by the diet, was also evaluated trough a histology study based on the assessment of morphometric measurements at gut level.

Samples collected from chickens challenged with E. coli LPS were used to study the acute phase response (APR), evaluating some biomarkers of toxicity (acute phase proteins, APP, in plasma) to understand the effects of LPS on the immune system of chicken fed with different diets. Novel APPs will be also explored and assessed in collaboration with Life Diagnostics, USA, a company partner of my PhD project.

Next year, my study will mainly focus on metabolomics at the University of Zagreb, where the unexplored metabolome of challenged chickens will be used to identify metabolites that could be used as biomarkers of health.


How does being part of an MSCA ITN impact me?

Having a chance to participate in an MSCA ITN such as the MANNA programme is one of the greatest professional experiences an Early Stage Researcher could have and will remain a milestone of my career’s development. MANNA is giving me the opportunity to link Animal Sciences to Omic technologies, expanding my scientific prospects as a researcher.

Through the programme, I had the opportunity to run in vivo trials on chickens, increasing my knowledge on nutritional and management requirements in running a good experiment on the animals. I also had the opportunity to carry out experimental feed planning and production on my company’s secondment in Belgium (Nuscience), which allowed me to integrate academic and commercial interests.

MANNA is providing me with the opportunity to participate in trainings and conferences that boost my knowledge in Animal Sciences in association with Omic technologies while also improving my communication and scientific skills.

Next years, I will travel to my second university (University of Zagreb) and one of my industrial partners (Life Diagnostics) to carry part of my PhD, so I will have the opportunity to work in different laboratories and environments. Through these collaborations, MANNA will offer me a real-world experience, which is very useful in building my future as a researcher.



Francesca Riva, Early Stage Researcher of the MANNA Project 3.


[1]Microbiota is formed by ecological communities of commensal, symbiotic and pathogenic microorganisms found in and on all multicellular organisms studied to date, from plants to animals.

2Metabolome refers to the complete set of small-molecule chemicals found within a biological sample (blood, urine, faeces).



Survey button