Effects of loline-alkaloid-containing seeds or seed extract on in vitro gas production and apparent dry matter digestibility

ABSTRACT Objective Loline alkaloids produced by Epichloe endophytes in pastoral grass species have suggested potential antimicrobial and anthelmintic properties. Loline is considered nontoxic, but the known effects of loline and derivatives on ruminal fermentation are limited. Negative effects could outweigh potential pharmacological benefits in vivo. Therefore, loline’s effect on ruminal fermentation was assessed using an in vitro gas production technique. Materials and Methods Two experiments with 24-h in vitro gas production were conducted using an ANKOM gas production system. In Exp. 1, treatments were Festuca pratensis seeds either with loline (LS, 330 µg/mL) or without loline (NLS) as the sole substrate. In Exp. 2, treatments were Lolium perenne (perennial ryegrass) only (RGS), ryegrass with loline-containing seed extract (RGL, 330 µg/mL), or ryegrass with non-loline-containing seed extract (RGN). Cumulative gas production was measured over 24 h, and apparent DM digestibility and pH were collected at the end. Data were analyzed using a linear mixed effect regression in Exp. 1, and in Exp. 2 data were fitted to Orskov’s nonlinear model to determine rate and extent of gas production. Results and Discussion At 24 h, NLS had a 9% greater (P Implication and Applications Loline needs further study as a potential pharmaceutical to be used on gut-dwelling organisms without negatively affecting rumen fermentation.