Vitamin A is an essential micronutrient and has important functions such as vision, growth, reproduction embryogenesis, cellular differentiation, and proliferation, immune function and epithelial protector in the organism. Biotechnological production of vitamins is increasing due to their advantages and significant advances. The vitreoscilla hemoglobin (VHb) gene is extremely effective in binding oxygen and conducting it under hypoxic conditions. In this study, the production of vitamin A in E. herbicola (wild type) and its recombinant strains was investigated in LB medium and M9 medium (containing high concentrations (1%) of different carbon sources). The maximum production of vitamin A of the recombinant strain with the hemoglobin gene (vgb+) was observed in including glucose and sucrose M9 medium and their total product levels in vgb+ recombinant strain were 0.14 µg/ml and 0.1 µg/ml, respectively. The vitamin A production in the M9 medium with glucose and sucrose were 2-fold and 1.4- fold higher than that of the wild strain, respectively. The extracellular product level (0.07 µg/ml) in LB was 7-fold higher than wild strain at 48 h. These results reveal that the expression of VHb in E. herbicola in the both LB and M9 medium (containing 1% glucose and 1% sucrose, specially) increase the vitamin A production.

The purpose of this study was to determine the effects of selenium, vitamin E, vitamin A, and vitamin D3 treatments on reproductive parameters in Awassi sheep fed solely dry grass and grain stubble during the breeding season with estrus synchronization. Seventy-five sheep were implanted with intravaginal sponges containing 20 mg of flugestone acetate for 9 days for estrus synchronization. On the day the sponges were inserted, the first group received an intramuscular injection of a supplement containing 200,000 IU of vitamin A, 30,000 IU of vitamin D3, and 20 mg of vitamin E, as well as a supplement containing 1 mg of sodium selenite and 60 mg of vitamin E. The second group was the control group, with no supplementary vitamin injected. On the day of sponge removal, the sheep received intramuscular injections of 500 IU PMSG and 250 mcg cloprostenol sodium in both groups. The sheep in the first group were given a second injection of the supplement on the same day that contained 20 mg of vitamin E, 30,000 IU of vitamin D3, and 200,000 IU of vitamin A. The sheep that showed signs of estrus were mated naturally after the estrus synchronization. Estrus rates were 86.11% and 85.29%, conception rates were 74.19% and 58.62%, pregnancy rates were 63.88% and 50%, lambing rates were 100% and 100%, and litter size was found to be 126.08% and 123.52% in Group I and II, respectively (P=0.858). Although there was no significant difference in the reproductive characteristics between the groups (P>0.05), Group I had a greater pregnancy rate and litter size. During the breeding season, it is believed that the regular application of vitamin and mineral supplements on a program basis in sheep fed only dry pasture and grain stubble contributed to fertility.