Prickly pear byproduct (Opuntia spp.) silage inclusion in dairy sheep diet: Effects on chemical, nutritional, and microbiological characteristics of milk and cheese

: Bioactive compounds often remain in agro-industrial by-products. Feeding dairy sheep with prickly pear by-product silage may enhance the chemical composition and bioactive content of milk and cheese. This study investigated these effects on the chemical and nutritional composition and bioactive compounds content of both milk and cheese. A total of 12 Valle del Belice breed ewes approximately 90 d in milking, balanced for parity, body weight, and daily milk yield (1.038 ± 0.144 kg/d), were selected and assigned to 3 experimental diets following a Latin square design with each period lasting 14 d. The diets with the same crude protein and neutral detergent fiber were: 1) control (CTR) diet with hay and concentrate; 2) prickly pear peels (PPP) diet with PPP silage, hay and concentrate; and 3) pulp, peels and seeds (PPS) diet with PPS silage, hay and concentrate. Both bulk milk and cheese samples were analyzed for their chemical and nutritional composition and microbiological characteristics, including microbiota profiling via 16S rRNA analysis. Results showed no significant changes in the chemical composition of milk and cheese. However, supplementation with prickly pear by-products increased their total phenolic content and antioxidant capacity. Cheeses produced from the experimental diets (PPP and PPS) exhibited higher concentrations of eucomic and piscidic acids. Cheese fatty acid composition and microbiological characteristics were largely unaffected by the dietary treatments. Sensory evaluation revealed significant differences among samples, but these did not impact overall consumer acceptance. The by-products of prickly pear fruits can therefore be advantageously used in the feeding of dairy sheep, improving the nutritional characteristics of cheeses.