115 Solubility and degradation of human fertility-promoting molecules in a rumen environment

Abstract

Abstract Endometrial epithelial of cows conceiving was associated to gene set enrichment of pathways associated to synthesis, metabolism, and degradation of myo-inositol pathways (Physiol. Genomics 54: 71-85, 2022). Progesterone-modulated transcription also indicated an increase in oxidative phosphorylation pathways in the endometrial epithelial of cows. Thus, modulation of myo-inositol and oxidative phosphorylation pathways can favor conception rates in cattle. Oral supplementation with pyrroloquinoline Quinone (PQQ), an antioxidant, and inositol isomers (myo- and D-chiro-inositol) has been proven to be beneficial for fertility of women undergoing assisted reproductive biotechnologies. However, oral supplementation of these compounds to ruminant species has not been evaluated. It is unknown if PQQ and inositol isomers are soluble in the rumen environment, if they are degraded by the microbial populations which exist in this environment, or the timeframe for the ruminal degradation of these molecules resulting from oral supplementation. The objectives of this study were to 1) evaluate disappearance (solubility) of different of inositol isomers and PQQ; and 2) to quantify the in-vitro ruminal degradability of inositol isomers and PQQ over time. Inositol isomers and PQQ (0.25 g) were placed in Ankom bags and heat sealed. The bags were placed in glass beakers with an artificial saliva solution and rumen fluid, then incubated at 39 C in a warm shaker bath to simulate ruminal digestion for 0, 1, 2, 4, 8, 12, 24, and 48 h. These were then evaluated for disappearance of each form of inositol from the Ankom bag and repeated for a total of five replicates. For the second trial, only myo-inositol was evaluated. In addition to bag removal at the same time points, duplicate ruminal fluid samples were collected for myo-inositol concentration determination. This trial had seven replicates. For all forms of inositol 0.00% was removed at 0 h, and by 1 h 99.0 % inositol had disappeared (P > 0.05). There were two exceptions, PQQ, at 1 h was less (P < 0.0001; 96.33 %) and at 4 h (98.46 %). For the second trial, myo-inositol disappearance increased (P = 0.0001) from 0.00 % at 1 h to 99.53 % at 4 h and remained constant (P > 0.05) for subsequent sampling times. Ruminal fluid concentration of myo-inositol increased (P < 0.0001) from 0.197 to 5.39 g/L, and remained constant (P > 0.05) until h 24 when it had decreased (P < 0.0001) to 2.766 g/L, and decreased P < 0.0001) further by 48 h to 0.377 g/L. Ruminal concentration of myo-inositol was not different (P > 0.05) between 0 h and 48 h. These data indicates that inositol isomers and PQQ are soluble in the rumen environment, though not immediately, with myo-inositol concentrations peaking between 12 and 24 h and disappearing mostly by h 48.