Profiles of Blood Amino, Fatty and Volatile Acids in Awassi Ewes Across Different Reproductive Stages and Their Association with Litter Size and Offspring Sex

This study aimed to investigate the dynamic changes in the blood profiles of amino acids, fatty acids, and volatile acids in Iraqi Awassi ewes across different reproductive stages, and to evaluate their associations with litter size and offspring sex. A total of thirty mature ewes were selected. Blood samples were collected via jugular venipuncture at five key reproductive stages: day 0 (pre-mating), 14 days post-mating, and at 45, 75, and 135 days of gestation. Amino acid concentrations were determined using High-Performance Liquid Chromatography (HPLC), whereas fatty acids and volatile acids were analyzed by Gas Chromatography (GC) at each reproductive stage. The concentrations of both essential and non-essential amino acids declined significantly (P ≤ 0.0001) as pregnancy progressed, with the lowest levels observed on day 75 of gestation. Furthermore, saturated fatty acid levels were significantly higher (P ≤ 0.0001) during mid-gestation (day 75) compared to the other reproductive stages. In contrast, unsaturated fatty acid levels showed a declining trend toward the end of gestation. Additionally, volatile acid levels increased significantly (P ≤ 0.0001) up to mid-gestation (day 75). However, no significant associations were observed between amino acid concentrations and either litter size or offspring sex, except for asparagine, which was significantly higher (P ≤ 0.003) in ewes carrying male fetuses compared to those carrying females. The concentrations of fatty acids and volatile acids showed no significant association with either litter size or offspring sex. In conclusion, the blood profiles of amino acids, fatty acids, and volatile acids may serve as valuable biomarkers for pregnancy detection and for evaluating the nutritional requirements of the developing embryo across different reproductive stages. These findings have the potential to enhance reproductive management strategies and contribute to the improvement of sheep breeding programs.