# Effects of Including Partially Destoned Olive Cake in Sheep Diet on Meat Quality and Salami Production

## TL;DR

Adding olive cake to sheep diets improves meat and salami quality while reusing agricultural waste.

## Contribution

This study demonstrates that feeding sheep partially destoned olive cake enhances meat and salami quality through improved lipid profiles and antioxidant properties.

## Key findings

- Sheep fed with olive cake had higher carcass weight and better lipid profiles, including increased monounsaturated fatty acids.
- Salami made from olive cake-fed sheep meat showed reduced weight loss and lower lipid oxidation during ripening.
- Processed products exhibited satisfactory sensory and microbiological properties with no safety concerns.

## Abstract

At the end of their productive lifespan, sheep often yield meat of limited commercial value, while substantial quantities of by-products from olive oil production remain underutilized. The present study investigated the effects of incorporating processed olive oil residues into sheep diets on meat quality and derived products, with the dual aim of valorizing an agro-industrial by-product and improving product sustainability. Over a 14-week feeding trial, two groups of sheep were administered isoenergetic concentrate diets, one of which included destoned olive cake. Following the experimental period, meat from each group was processed into different types of salami. Sheep receiving the destoned olive cake diet exhibited increased carcass weight and meat characterized by a more favorable lipid profile, including higher levels of beneficial fatty acids and bioactive plant-derived compounds with recognized antioxidant properties. Salami produced from this meat showed reduced weight loss during ripening, lower lipid oxidation, and satisfactory sensory attributes, without evidence of microbial safety concerns. Overall, these findings indicate that the inclusion of destoned olive cake in sheep feed can improve meat and processed product quality while promoting the sustainable reuse of olive oil by-products, offering benefits for both livestock production systems and environmental management.

The valorization of cull sheep and the incorporation of agro-industrial by-products into animal feeding represent effective approaches to enhancing the sustainability of small ruminant production systems. This study investigated the effects of dietary inclusion of 17% partially destoned olive cake (OC) in the concentrate fed to Valle del Belice ewes on carcass characteristics, as well as on meat and salami quality. A 14-week feeding trial was conducted on 124 animals allocated to a control (CTR) and an experimental (EXP) group, balanced for parity, days in milk, and daily milk yield. At the end of the trial, five animals per group were slaughtered and their meat was processed into three types of salami: 100% sheep meat (SM), 90% sheep meat with 10% beef heifer brisket (HB), and 90% sheep meat with 10% pork backfat (PB). Meat and salami were evaluated for chemical composition, fatty acid profile, polyphenol content, antioxidant capacity, lipid oxidation, microbiological status, textural properties, and sensory characteristics. Dietary OC supplementation resulted in increased carcass weight, separable fat, intramuscular fat content, and monounsaturated fatty acids—particularly oleic acid—along with higher polyphenol levels and antioxidant activity. Salami produced from OC-fed ewes exhibited reduced weight loss during ripening, lower lipid oxidation, an improved MUFA/SFA ratio, and satisfactory sensory attributes. Microbiological analyses indicated a dominance of lactic acid bacteria and coagulase-negative staphylococci, with no pathogenic microorganisms detected. Overall, the inclusion of olive cake in the diet enhanced meat and processed product quality, supporting the valorization of olive oil by-products within circular economy frameworks.