Dry olive cake, an olive by-product, as a functional fiber source in diets for laying pullets: effects on growth and gut health.
- 1Department of Animal Production, Faculty of Veterinary Science, Regional Campus of International Excellence "Mare Nostrum", University of Murcia, Espinardo, Murcia, 30100, Spain.
- 2Department of Animal Production, Faculty of Veterinary Science, Regional Campus of International Excellence "Mare Nostrum", University of Murcia, Espinardo, Murcia, 30100, Spain. Electronic address: [email protected].
- 3Department of Animal Health, Faculty of Veterinary Science, Regional Campus of International Excellence "Mare Nostrum", University of Murcia, Espinardo, Murcia, 30100, Spain.
Abstract
The European Union is the world's largest producer of olives (Olea europaea), generating substantial amounts of by-products that require revalorization. Among these, dry olive cake is rich in dietary fiber and phenolic compounds, making it a promising ingredient for poultry nutrition. This study evaluated the effects of including 2% dry olive cake in laying pullet diets compared with a control diet, assessing performance, apparent total tract retention (ATTR), intestinal morphology, gene expression, cecal microbiota, and volatile fatty acids (VFA) after 28 days of trial. Two diets were formulated: a control diet with 2% sepiolite and a diet with 2% dry olive cake (DOC), administered to 6-weeks-old pullets housed in 12 cages (6 replicate cages per dietary treatment, with three birds per cage). DOC improved ATTR (P<0.05), while performance remained unaffected (P>0.05). Gut morphology improved in the duodenum, where crypt depth decreased and the villus length-to-crypt depth ratio increased (P<0.05). Gene expression analysis revealed downregulation of inflammatory genes (IL-2, TNF-α, IFN-γ) and RARRES1, alongside upregulation of genes related to barrier function (MUC2), antimicrobial defense (AvBD4), and fatty acid transport (FAT-CD36) (P<0.05). Cecal microbiota showed trends toward distinct community structures (Jaccard and Bray-Curtis indices; P<0.10), with higher richness (Chao1 and Fisher; P<0.05), greater Butyricicoccaceae, and reduced Proteobacteria (P<0.05). These changes were accompanied by greater total VFA production, particularly acetic, propionic, butyric, and valeric acids, with a higher proportion of butyrate (P<0.05). Overall, 2% dry olive cake improved gut health, microbiota, and nutrient utilization without affecting performance, supporting its potential as a sustainable, functional fiber source in the feed of laying pullets.
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BibTeX
@article{ruiz2026olive,
title = {{Dry olive cake, an olive by-product, as a functional fiber source in diets for laying pullets: effects on growth and gut health.}},
author = {Eduardo Ruiz and Fuensanta Hernández and Josefa Madrid and Cristian Jesús Sánchez and Ana Montalbán and Lucía Ayala and Nieves Ortega and Silvia Martínez-Miró},
journal = {Poultry science},
year = {2026},
month = oct,
doi = {10.1016/j.psj.2026.107906},
url = {https://europepmc.org/article/MED/42849227},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Dry olive cake, an olive by-product, as a functional fiber source in diets for laying pullets: effects on growth and gut health.
AU - Eduardo Ruiz
AU - Fuensanta Hernández
AU - Josefa Madrid
AU - Cristian Jesús Sánchez
AU - Ana Montalbán
AU - Lucía Ayala
AU - Nieves Ortega
AU - Silvia Martínez-Miró
PY - 2026
DA - 2026/10/05
JO - Poultry science
DO - 10.1016/j.psj.2026.107906
UR - https://europepmc.org/article/MED/42849227
AB - The European Union is the world's largest producer of olives (Olea europaea), generating substantial amounts of by-products that require revalorization. Among these, dry olive cake is rich in dietary fiber and phenolic compounds, making it a promising ingredient for poultry nutrition. This study evaluated the effects of including 2% dry olive cake in laying pullet diets compared with a control diet, assessing performance, apparent total tract retention (ATTR), intestinal morphology, gene expression, cecal microbiota, and volatile fatty acids (VFA) after 28 days of trial. Two diets were formulated: a control diet with 2% sepiolite and a diet with 2% dry olive cake (DOC), administered to 6-weeks-old pullets housed in 12 cages (6 replicate cages per dietary treatment, with three birds per cage). DOC improved ATTR (P<0.05), while performance remained unaffected (P>0.05). Gut morphology improved in the duodenum, where crypt depth decreased and the villus length-to-crypt depth ratio increased (P<0.05). Gene expression analysis revealed downregulation of inflammatory genes (IL-2, TNF-α, IFN-γ) and RARRES1, alongside upregulation of genes related to barrier function (MUC2), antimicrobial defense (AvBD4), and fatty acid transport (FAT-CD36) (P<0.05). Cecal microbiota showed trends toward distinct community structures (Jaccard and Bray-Curtis indices; P<0.10), with higher richness (Chao1 and Fisher; P<0.05), greater Butyricicoccaceae, and reduced Proteobacteria (P<0.05). These changes were accompanied by greater total VFA production, particularly acetic, propionic, butyric, and valeric acids, with a higher proportion of butyrate (P<0.05). Overall, 2% dry olive cake improved gut health, microbiota, and nutrient utilization without affecting performance, supporting its potential as a sustainable, functional fiber source in the feed of laying pullets.
SN - 0032-5791
SN - 1525-3171
ER -