Effects of dietary fat source on lutein, zeaxanthin and total carotenoids content of the egg yolk in laying hens during the early laying period

ABSTRACT

1. The study was conducted to investigate the effects of different dietary levels of an unsaturated or saturated fat source and the effects of different dietary energy levels in laying hen diets on the carotenoid content of the egg yolk.

2. Seventy-two ISA Brown laying hens aged 22 weeks old were allocated, for a 10 week period, to three treatments: control diet (HE group) with a 3.4% supplemented fat containing 2.1% soybean and 1.3% palm oil as fat sources and a ratio of unsaturated to saturated fatty acid (u/s) of 3.33; a lowered energy diet with 2.4% supplemented fat containing 1.4% soybean and 1.0% palm oil and u/s of 3.41 (LE+high u/s); a lowered energy diet with 2.4% supplemented fat containing 0.5% soybean and 1.9% palm oil and a u/s of 2.39 (LE+low u/s). A marigold plant extract supplement was used as a source of lutein.

3. Performance parameters (feed consumption, feed conversion, body weight), egg production rate and egg quality parameters were similar between treatments. Dietary fat digestibility at the middle of the study period was not different. Egg yolk total fat content was similar in all treatments at the middle and at the end of the study period.

4. Lutein, zeaxanthin, cis-lutein and total carotenoids content were significantly lower in eggs produced from the LE+low u/s group compared to those from the HE and the LE+high u/s groups (P < 0.01 for all parameters).

5. It was concluded that feeding laying hens with a diet containing 1% less supplemented fat and a lower u/s ratio compared to a control diet and to a diet with 1% less supplemented fat with a higher u/s ratio resulted in a significant reduction of carotenoid expression in the egg yolk at the end of experimental period. Performance and egg quality parameters were not affected by treatments.

KEYWORDS:

• Carotenoids
• laying hens
• lutein
• saturated fat
• unsaturated fat

Acknowledgments

The authors would like to thank Professor George Zachariadis from the Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University, for technical assistance and providing the equipment for analysis of titanium in samples. The authors also thank the Assistant Professor Ioannis Karapanagiotidis from the Department of Icthyology and Aquatic Environment of University of Thessaly in Volos for provision of the adiabatic bomb calorimeter. Finally, the authors would like to thank Professor Ioannis Amvrosiadis and Assistant Professor Aikaterini Papavergou of the Laboratory of Food Technology of Animal Origin, Faculty of Veterinary Medicine, Aristotle University, for providing us access to perform chemical analysis.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This research was funded by Kemin Europa N.V. (project number 92358; Research Committee of Aristotle University, Thessaloniki, Greece). Kemin Europa N.V. provided the supplement Oro Glo Layer (Kemin Europa NV, Herentals, Belgium). There was no further involvement of the funding source in study design; in the collection, analysis and interpretation of data; in the writing of the report; and in the decision to submit the article for publication.