PSI-7 The dietary supplementation of fatty acids and choline modulates the concentration of metabolites in embryonic tissues during elongation.

Abstract The transition between a spherical-shaped blastocyst to an elongated conceptus is required for proper early embryonic development in cattle. During the peri-elongation period, embryonic tissues have increased uptake of lipids that will support trophectoderm and endoderm formation. Therefore, our objective was to provide a dietary supplementation strategy containing rumen-inert mono- and polyunsaturated fatty acids and rumen-protected choline to cater to the specific needs of the elongating conceptus. One hundred suckled multiparous Angus cows were randomly assigned on d -30 to receive either TARG) 100 g of a rumen-inert mono- and polyunsaturated fatty acid source (Essentiom; Church and Dwight Co., Inc., Princeton, NJ) plus 60 g of a rumen-protected choline source (ReaShure; Balchem, Montvale, NJ) or CON) 114 g of a saturated fatty acid source (Energy Booster 100; Milk Specialties, Eden Prairie, MN). Treatments were top-dressed daily into a similar total mixed ration until d 30. All cows were synchronized using a 7-day CO-synch+CIDR protocol and received timed artificial insemination by the same technician on d 0. On d 16, uterine flushing was conducted in a subset of cows (CON = 20 and TARG = 23) to determine the presence and length of the embryo, and uterine luminal fluid was analyzed for the concentration of interferon tau (IFNT). Only samples with fully recovered elongating embryos were used for metabolomics analysis (CON = 6 and TARG = 6). In addition, blood was collected to determine the concentration of progesterone (P4). The effects of treatment, group, and their interaction on P4 and IFNT were analyzed by ANOVA. Prior to statistical analysis, the concentration of metabolites in embryonic tissues were subjected to loess normalization. Depending on normality, data were analyzed either by ANOVA or Wilcoxon-Mann-Whitney test. The concentration of progesterone and IFNT did not differ between treatments (P = 0.57). The concentration of IFNT in flushing media in CON was 3693.92 ± 5133.24 pg/mL and in TARG was 4132.62 ± 5742.87 pg/mL. There were seven significantly different metabolites (P ≤ 0.05) and 17 tended to be significant (0.05 < P ≤ 0.1) in embryonic tissues at d 16. The metabolites modulated in embryonic tissues belonged to triglyceride, phosphatidylinositol, acylcarnitine, lysphosphatidylglycerol, carboxylic acid, amino acid, phosphatidylethanolamine, phosphatidic acid, diglyceride, phosphatidylcholine, lysophosphatidylethanolamine, and lysophosphatidylserine classes. Among these metabolites, phosphatidylcholines, PC (42:3) and PC (36:5), and one diglyceride were greater in TARG. Meanwhile, phosphatidylinositols, three diglycerides, lysophosphatidylethanolamines, and lysophosphatidylserines were greater in CON. Altogether, the metabolites greater in TARG are related to cell membrane development and lipid metabolism, whereas the metabolites greater in CON are related to structural support in cell membranes, lipid metabolism, and cell-mediated cell signaling. Potential implications for embryo-maternal communication and reproductive outcomes deserve further investigation.