Abstract
BackgroundExtra-virgin olive oil (EVOO) represents an important food in Mediterranean diet due to its favorable effects on human and animal health derived from the consumption of polyphenols. We studied the effects of dietary EVOO differing in polyphenols levels on egg quality.MethodsA total of 150 laying hens were allotted into three groups over 10 weeks of the experimental period. The three diets were based on wheat-soybean meal with added oils at 2.5%. Hens were fed the following diets: (1) commercial diet containing sunflower oil (Control), (2) diet EVOO from Cima di Bitonto variety (low-polyphenols content; Low-P), and (3) diet EVOO from Coratina variety (high-polyphenols content; High-P). The performance of the hen, the qualitative traits of eggs, and the fatty acid composition and cholesterol content of egg-yolk were measured.ResultsNone of the egg productive parameters studied were influenced by dietary treatment, except for yolk color score that was enhanced in hens fed the both EVOO diets (P < 0.05). Feeding high-polyphenols EVOO reduced serum cholesterol level in hens (P < 0.01) and egg-yolk cholesterol levels (as per egg; P < 0.05). The dietary supplementation of high-polyphenols EVOO raised the polyunsaturated fatty acids (PUFAs) composition and increased the content of oleic and linolenic acids in egg-yolk. Moreover, the atherogenic index in egg-yolk decreased linearly in accordance with increasing levels of dietary polyphenols (P < 0.01).ConclusionIn conclusion, a diet for hens consisting of high-polyphenols level from extra-virgin olive oil can improve the fatty acid quality of egg-yolk while lowering the egg-yolk cholesterol level, which could be a beneficial functional food for human health.
Highlights
Extra-virgin olive oil (EVOO) represents an important food in Mediterranean diet due to its favorable effects on human and animal health derived from the consumption of polyphenols
Eggs are an important source of nutrients due to their high quality protein and variety of vitamins and minerals, it is often recommended that people restrict their consumption since egg yolk contains nearly 30% lipids and high cholesterol content [13]
The best of our knowledge and based on these considerations, the present study was aimed to evaluate the effects of dietary supplementation with EVOO from olive cultivars differing in polyphenols levels on egg quality and egg yolk cholesterol
Summary
Experimental birds and management This study was conducted in the experimental poultry facility located at the University of Bari ‘Aldo Moro’, Italy, observing the animal welfare Legislative Decree 116/92, Council Directive 98/58/EC, received in Italy by Legislative Decree 146/2001, and Council Directive 2007/43/CE, received in Italy by the governmental Decree 181/2010 and Legislative Decree 267/2003. The extra-virgin olive oils used for experimental diets had a low- and high- total phenol concentration (138 vs 254 mg/kg) with an different hydroxytyrosol concentrations (17 vs 43 mg/kg), for Cima di Bitonto and Coratina variety respectively (Table 4); as determined by Oliveras-López et al [9]. Polyphenols and fatty acid analyses Quantitative and qualitative analysis of phenolic fraction of the extra virgin olive oils was performed according to the COI/T20/29doc (International Olive Council) for olive oil. The method is based on direct extraction of the phenolic minor polar compounds from olive oil by means of a methanol solution and subsequent quantification by high-performance ternary gradient liquid chromatograph (HPLC) [5]. In preparation for fatty acid (FA) composition analysis, samples of oil and egg-yolk (5 g each) were freeze-dried.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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 callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
