An alternative to restricted feeding in Iberian pigs using an agro-industrial by-product of olive oil

Traditional Iberian pig production is characterized for having a fattening period with a feeding based on acorn and pastures. During the previous growing period, the feeding is restricted to avoid undesirable weight gains. However, this procedure could cause feeding stress. The use of ad libitum diets based on olive by-products during the growing period may be an alternative to avoid this stress. Two diets based on olive by-products, one incorporating dry olive pulp in the feed (DD) and the other one incorporating olive cake in wet form (WD) were compared with a control standard diet group (CD). CD and DD diets were supplied once a day and WD diet was supplied ad libitum and supplemented with a specific feed given once a day. Comparisons were performed using ANOVA for: growth, backfat fatty acid profile, carcass composition, percentage of intramuscular fat (%IMF) and other quality meat traits (thaw, cook and centrifuge force losses, shear force, marbling, Minolta colours and myoglobin concentration). No significant differences between the treatment groups were observed for most of the traits. Although animals fed with DD and WD diets grew slower than those fed with CD during the growing period, no differences in the total average daily gain were observed. DD animals showed a higher carcass yield and less %IMF in loin. Olive-cake diets caused higher levels of unsaturation than CD one after the growing period. Lower centrifuge force losses were observed in WD than in CD. DD samples were paler and less red-coloured and has lower myoglobin content than CD and WD ones. Results (of this study within project TREASURE) suggest that WD diet could be a suitable feeding for growing period in traditional Iberian pig production since negative effects on growth, carcass and quality traits were not observed in the current study. Funded by European Union’s H2020 RIA program (Grant agreement no. 634476)