Stimulatory effects of fish oil and vitamin E on ovarian function of laying hen

Abstract

In recent years, there has been an increase in the consumption of omega-6 fatty acids (FAs) over omega-3. Moreover, the antioxidant nature of oil supplemented diet in human and animal studies is not clear. In this work, the n-3 effects on hen ovarian cells, ovarian dynamics, serum FA profiles and expression level of apoptosis genes in the presence or absence of vitamin E were studied. Sixty-eight laying hens were randomly divided into four groups and the groups were fed the following diets: basal diet +1.5% sunflower oil (control; C); basal diet +1.5% sunflower oil +1.1 U alpha-tocopherol/hen/day (E); basal diet +1.5% fish oil +1.1 U alpha-tocopherol/hen/day (n-3 + E); and basal diet +1.5% fish oil (n-3). In E, n-3 + E and n-3, small yellow follicle numbers were higher than control (p < .05). Large yellow follicle numbers as well as total numbers of follicles of n-3 + E and n-3 were higher (p < .05) than control and E. The rate of ovulation was significantly (p < .05) higher in n-3 (96%) compared to the control (89%). The proportion of intact primordial follicles in n-3 and n-3 + E was significantly more than control and E (p < .01). The expression of Bak (Bcl2 antagonist/killer) was significantly (p < .05) higher in control than the other groups. There was significant reduction in expression of Cas9 in n-3 and E compared to the control and n-3 + E (p < .05). While omega-3 and vitamin E can protect ovarian cells from apoptotic death, omega-3 source could have promoting roles on follicular development and ovulation rate, being independent of dietary vitamin E.

Highlights

• Despite the perceived importance of supplementing antioxidant with fatty acids, our results indicated that alone low level of n-3 has a great influence on ovary performance.

Keywords:

• Apoptosis
• follicogenesis
• n-3PUFA
• ovary
• vitamin E

Acknowledgments

The authors thank the employees of the Halajerd Research Station (Dr. M. Haji Nasrollah and Mr. A. R. Nemati), Karaj, Iran for animal care and Tekno Azma laboratory (Dr. P. Kavousi) for collaboration for fatty acid analysis. The authors also thank Ms. Lakshmi Gopal (Valerdoc Company) for editing of manuscript.

Disclosure statement

The authors declare no conflicts of interest.

Ethical Statement

The project was approved by the Ethical Committee for the care and use of experimental animals of Royan Institute.