Dietary Fish Oil and Vitamin E Reduce Cryoinjuries and Apoptosis in Vitrified Laying Hens' Ovarian Tissue.

The occurrence of cryoinjuries during ovarian tissue freezing necessitates development of methods that can overcome these challenges in cell and tissue cryopreservation. It has been hypothesized that omega-3 and vitamin E diet supplementation to the animal could be an appropriate strategy to preserve post-thaw ovarian quality. The laying hen is an appropriate animal model that can be used to study the effects of providing dietary supplements on the outcomes of ovary cryopreservation. The purpose of the study was to evaluate the dietary effects of fish oil, sunflower oil, and vitamin E on 68 laying hens according to the following treatments: basal diet + 1.5% sunflower oil (control; C); basal diet + 1.5% sunflower oil + 1.1 IU alpha-tocopherol/hen/day (E); basal diet + 1.5% fish oil + 1.1 IU alphatocopherol/hen/day (n-3+E); and basal diet + 1.5% fish oil (n-3). The effects on ovarian structure and preservation, apoptosis-related gene expression, and the fatty acid profiles in ovarian laying hen (n = 7 in each group) were studied. The number of intact primordial follicles in n-3+E group was significantly higher than other groups (85% vs. 71%, 72%, and 77% for n-3+E, C, E, and n-3, respectively; p < 0.01). There was a significant reduction in expression of Cas3, as well as Cas8, in n-3 and n-3+E than C and E (p ≤ 0.05). A trend to decrease in Bak (p = 0.089) and Bak/Bcl2 ratio (p = 0.095) in the mRNA was observed in n-3+E. Ovarian eicosapentaenoic acid (C20:5n3) concentration in n-3 was the highest among C, E, and n-3+E (p < 0.01). Docosahexaenoic acid (C22:6 n-3) concentrations in ovaries of the n-3 group were elevated five times more than control. The n-3: n-6 ratio in groups receiving omega-3 (n-3+E and n-3) was higher than other groups (p < 0.01). In conclusion, consumption of dietary omega-3 fatty acids with vitamin E improves the results of vitrification of ovarian tissues in laying hens.