JDS communications ·16 Jan 2026 ·Added 13 Nov 2026

Temporal changes in plasma choline and choline metabolite concentrations in response to an esophageal bolus of rumen-protected fish oil in early lactation cows fed rumen-protected choline.

Víctor Sáinz de la Maza-Escolà, Maria Federica Marchesi, Michele Dei Cas, Sara Casati, Fiorenzo Piccioli-Cappelli, Erminio Trevisi, Andrea Piva, Ester Grilli, Joseph W McFadden

Other & Emerging Fields

DOI ↗

Abstract

Fish oil (FO) is a rich source of n-3 fatty acids (FA), which may be preferable FA for hepatic phosphatidylcholine (PC) synthesis via the actions of phosphatidylethanolamine N -methyltransferase. Our objective was to determine whether feeding rumen-protected choline (RPC) increased concentrations of circulating PC enriched with n-3 FA in cows fed a bolus of rumen-protected FO. Eighteen Holstein cows (3.6 ± 2 [mean ± SD] lactations) were randomly assigned to 1 of 2 groups (n = 9/group) at -21 ± 3 d prepartum: unsupplemented (control [CON]) or supplemented with RPC (RPC; 0 or 60 g/d, respectively; 25% choline chloride; Ruprocol, Vetagro S.p.A., Reggio Emilia, Italy) until d 35 postpartum. At d 27 ± 4 postpartum, all cows were provided with a gelatin capsule containing 100 g of lipid-microencapsulated FO as an esophageal bolus (36% FO; 10.2 g of n-3 FA; Prototype 6, Vetagro S.p.A.). Cows were fed a TMR and milked twice daily. Blood was sampled at 0, 10, and 24 h relative to bolus delivery. Plasma was analyzed for choline and choline metabolites using liquid chromatography tandem MS. Data were analyzed under a mixed model with the random effect of cow and the fixed effects of treatment, hour, and their interaction. At h 0, plasma betaine concentrations were greater in RPC relative to CON; however, plasma choline concentrations were not modified by treatment. Following FO bolus administration, circulating trimethylamine N -oxide and dimethylglycine (DMG) were increased by h 10. Cows supplemented with RPC tended to have greater plasma DMG and methionine relative to CON. Although no changes were detected for plasma lysophophatidylcholine (LPC)-22:5, LPC-22:6, total LPC, PC-16:0/22:5 or PC-18:0/22:5, the RPC group had increased plasma LPC-20:5, PC-16:0/22:6, and PC-18:0/22:6 compared with CON. Plasma PC-18:0/20:5 and total PC concentrations were greater in RPC cows relative to CON by h 24. We conclude that RPC feeding augmented the ability of dietary FO to increase plasma PC concentrations in early-lactation cows.