Caprine milk fatty acid responses to dietary dried grape pomace

Abstract

Including grape pomace in goat diets presents a potentially valuable strategy for enhancing the sustainability of goat farming and mitigating environmental risks. This work aimed to investigate the impact of dietary dried grape pomace (DGP) on milk yield, milk composition and milk fatty acid (FA) profile in goats. Gas chromatography was utilised to obtain an extensive profile of FA in milk fat. Dry matter intake, as well as milk yield and composition were not altered by dietary DGP. Despite the predominance of linoleic acid (LA, 18:2 cis-9,cis-12) in the lipids of DGP and the presence of phenolic compounds, its inclusion in the diet did not negatively affect the quantitatively main groups of FA. Furthermore, there was no significant impact on butyric, caproic, caprylic, and capric acids, the major 18:1 trans isomers, including vaccenic acid (18:1 trans-11), LA, α-linolenic acid (18:3 n-3), and the long chain polyunsaturated n-6 and n-3 FA. However, rumenic acid in milk fat was significantly reduced from 0.36 to 0.30 g/100 g of total fatty acid methyl esters. This study supports that up to 6%, DGP can be safely included in conventional dairy goat diets without compromising the production results or altering to great extent the milk FA profile.

HIGHLIGHTS

• Milk changes due to dried grape pomace (DGP) consumption were assessed in goats.

• Milk yield increased without changes in milk composition following DGP consumption.

• Some minor FA contents were modified by DGP.

• DGP had no impact on most FA related to milk fat’s nutritional properties.

Keywords:

• Dairy goats
• milk composition
• wine by-product

Acknowledgements

This paper is the result of a research stay of Andrés L. Martínez Marín at the Department of Veterinary Sciences of the University of Turin (Italy). The authors gratefully thank the farmer, Dr. Aurelio Ceresa, for technical assistance and care of animals, Mrs. Vanda Maria Malfatto (DISAFA, Turin, Italy) for the chemical analysis of feedstuffs, and Dr. Miguel Angel de la Fuente (CIAL, Madrid, Spain) for the comments and critical lecture of the manuscript.

Ethical approval

Ethical approval was not needed according to EU regulations because the experimental procedures were not likely to cause pain, suffering, distress or lasting harm equivalent to, or higher than, that caused by the introduction of a needle in accordance with good veterinary practice.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

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

Additional information

Funding

This work was supported by the University of Turin (Project CORP_RILO_20_01—Strategies for improving the sustainability of livestock farms).