Effects of Olive Cake on the Performance, Digestibility, Blood Parameters, and Intestinal Villi of Bísaro Pigs

Olive oil production generates by-products, such as olive cake (OC), which can be used in animal feed, reducing the environmental impact. This study assessed the effects of OC in pig diets on intestinal morphometry and blood parameters. Twenty-four Bísaro pigs were randomly assigned to three treatments: OC0 (control), OC15 (15% dehydrated OC), and OC25 (25% dehydrated OC) for 93 days. The apparent total tract digestibility (ATTD) of dry matter (DM), organic matter (OM), crude protein (CP), crude fat (CF), and fiber (NDF) was evaluated through total feces collection. No significant differences in average daily gain (ADG) or feed conversion ratio (FCR) were found (p > 0.05). However, average daily feed intake (ADFI) increased from 2.84 kg (control) to 3.46 kg (OC15) and 3.64 kg (OC25). OC inclusion increased the ADFI of CF (90.8 g to 171.5 g and 169.2 g) and NDF (586.8 g to 896.6 g and 1115.4 g). The ATTD of all parameters decreased with 25% OC. The digestible intake of DM, OM, and CP was unaffected, but CF intake was higher in OC-fed groups (p = 0.005). Histomorphometric analysis revealed no significant differences in villi size. Lymphocyte counts were higher in OC25 (p < 0.05). This study suggests that up to 15% OC inclusion is feasible without compromising the pigs' performance.