Abstract
Simple SummaryOlive polyphenols exert many favorable properties, such as an antioxidative effect in humans, but are poorly studied in animals, especially in pigs. Therefore, we conducted a trial including olive leaf extract (OLE), which is rich in polyphenols, in pigs fed a linseed oil-enriched diet, which is a known cause of postprandial oxidative stress. OLE exerted some antioxidative effects in piglets fed a polyunsaturated fatty acid (PUFA)-rich diet without any negative effects, even when included in a higher concentration than that proposed for humans. Additionally, the inclusion of OLE did not compromise the zootechnical performance of the piglets as in the case of the dietary inclusion of olive leaves. Therefore, OLE could be used as an effective feed additive for beneficial effects on intestinal health and meat quality, among others.The aim of the current study was to assess the antioxidative effects of the dietary supplementation of olive leaf extract (OLE) in different concentrations compared to those of vitamin E in piglets under conditions of dietary n-3 PUFA-induced oxidative stress. Forty-eight castrated male piglets (10.6 ± 0.99 kg) were fed the following experimental diets: Cont− (low-fat diet, no supplement), Cont+ (high linseed oil diet, no supplement), Vit-E (as Cont+, 105 IU vitamin E/day), OLE-1 (as Cont+, 3.84 mg hydroxytyrosol equivalents (HEQs)/day), OLE-2 (as Cont+, 38.4 mg HEQ/day), and OLE-3 (as Cont+, 96 mg HEQ/day). After 21 days of feeding, the experimental diets, blood and urine samples were collected to assess the extent of the oxidative stress. Results indicated that diet OLE-1 lowered the activity of gamma-glutamyl transferase, protected DNA (measured as DNA tail %) and altered urinary 8-hydroxy-2’-deoxyguanosine (8-OHdG). Dietary vitamin E lowered the levels of urinary F2-isoprostanes, as well as of plasma malondialdehyde and γ-tocopherol, but raised the plasmatic α-tocopherol and altered the level of urinary 8-OHdG. In conclusion, only minor positive effects of dietary OLE on the oxidative stress parameters were observed. Additionally, OLE did not show concentration dependence.
Highlights
Olive plant (Olea europaea L.) contains different polyphenols, of which some are suggested to have antioxidative and other beneficial properties in humans [1] and possibly in farm animals—according to scarce literature data
The effectiveness of hydroxytyrosol and its derivatives as antioxidants in humans is acknowledged by the European Food Safety Authority through a health claim, which states that 5 mg of hydroxytyrosol equivalents (EQs) ingested with olive oil can protect low-density lipoproteins (LDL) from oxidation [2]
Oxidative stress was induced in Cont+, Vit-E and the three olive leaf extract (OLE)-supplemented groups by including high linseed oil, which was exchanged for wheat starch in the diet fed to the Cont−
Summary
Olive plant (Olea europaea L.) contains different polyphenols, of which some are suggested to have antioxidative and other beneficial properties in humans [1] and possibly in farm animals—according to scarce literature data. The effectiveness of hydroxytyrosol and its derivatives as antioxidants in humans is acknowledged by the European Food Safety Authority through a health claim, which states that 5 mg of hydroxytyrosol equivalents (EQs) ingested with olive oil can protect low-density lipoproteins (LDL) from oxidation [2]. To the best of our knowledge, no studies in the literature have thoroughly evaluated the potential of olive polyphenols to reduce oxidative stress in farm animals. Trials with a limited number of observed parameters were conducted to study the antioxidant effects of olive polyphenols in pigs
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
