Effect of co-products from olive-oil production chain on rumen microbial communities: an in vitro study

Abstract

Several edible agro-industrial co-products have been studied as unconventional ingredients in ruminant diets to reduce the environmental impact of food production chains. When the chemical profile of co-products is characterised by the presence of bioactive molecules, they represent a promising tool to modulate rumen microbiota activity. In the Mediterranean area, the olive oil production chain generates olive oil pomace and olive tree leaves post-milling that are animal edible bio-waste. Two in vitro trials were carried out to investigate the effect of olive oil pomace and olive tree leaves as dietary ingredients on rumen fermentation and microbiome ecology. Two experimental diets, respectively containing olive oil pomace or olive tree leaves, and the related control diets, formulated to be isoproteic and isoenergetic, were fermented and then collected after 6h and 24h. Olive oil pomace increased the content of C18:1 c9 and C18:3 c9c12c15. Considering the microbial communities, the genera Butyrivibrio, Fibrobacter, and Pseudobutyrivibrio were less abundant, while Christensenellaceae_R-7_group, Manheimia, Uruburuella were more abundant in rumen liquor fermented with olive oil pomace. Similarly, the diet containing olive tree leaves increased the content of C18:1 c9 and C18:3 c9c12c15 and decreased the abundance of Pseudobutyrivibrio and Rikenellaceae_RC9_gut_group. Data reported in this study showed that the two by-products deriving from the olive oil production chain are effective in modulating microbial community in a selective manner.

HIGHLIGHTS

1. Unconventional ingredients in dairy-ruminant feeding to valorise agro-industrial co-products.

2. Unconventional feeds to improve the circularity of animal production chain.

3. Olive oil pomace and olive tree leaves as tools to modulate rumen fermentation and increase the microbial synthesis of functional molecules.

Keywords:

• By-products
• polyphenols
• rumen microbiota
• ruminant feeding
• sustainability

Acknowledgments

The authors acknowledge the financial support for this project provided by: (1) transnational funding bodies, partners of the H2020 ERA-NETs SUSFOOD2 and CORE Organic Cofund, under the Joint SUSFOOD2/CORE Organic Call 2019; (2) MIPAAFT, Italian Government: Concessione di contributi finalizzati alla realizzazione di progetti di ricerca nell’ambito del fondo per gli investimenti nel settore lattiero caseario (Mipaaft) D.M. n. 27443 del 25/09/2018. “Alimentazione di precisione con sanse da olio extra vergine di oliva: modulazione del metabolismo delle bovine da latte per la messa a punto di nuovi prodotti lattiero-caseari nutraceutici. ACRONIMO: EVOLAT” (DG DISR - DISR 04 - Prot. Uscita N.0016807 del 11/04/2019). Grant identifier (CUP): B14I18000380001; (3) Italian Government by PNRR funds to National Research Centre for Agricultural Technologies (CN2- Agritech, spoke 9). V. Bolletta was granted fellowship by Programma Operativo Nazionale “Ricerca e Innovazione” 2014-2020 (azione DOT1323115 – CUP: J95F21002560009). The Authors thank dr Caterina Bio (Lanini srl) for her technical assistance and Prof Rui Bessa and Prof Susana Alves for the setting up of the DMA protocol analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Data availability statement

The data that support the findings of this study are available from the corresponding author, M.P., upon reasonable request.

Additional information

Funding

This study was carried out within the Agritech National Research Center and received funding from the European Union Next-Generation EU (PIANO NAZIONALE DI RIPRESA E RESILIENZA (PNRR) – MISSIONE 4 COMPONENTE 2, INVESTIMENTO 1.4 – D.D. 1032 17/06/2022, CN00000022). This manuscript reflects only the authors’ views and opinions, neither the European Union nor the European Commission can be considered responsible for them.