COMPARISON OF 2 AMMONIATION PROCEDURES TO REDUCE THE TOXICITY OF ENDOPHYTE-INFECTED TALL FESCUE SEED FED TO RATS (VOL 21, PG 387, 1998)

To determine the effect of extending the duration of ammonia (2% dry m atter basis) treatment from I to 5 wk on the toxicity of endophyte-inf ected tall fescue seed, 60 male Harlan Sprague-Dawley rats were random ly assigned to the following six treatments during a 28-d trial: endop hyte-free (E-) endophyte-infected (E+) I wk ammoniated endophyte-free (1AE-) I wk ammoniated endophyte-infected (1AE+), 5 wk ammoniated endo phyte-free (5AE-) and 5 wk ammoniated endophyte-infected (5AE+) tall f escue seed. The concentration of total pyrrolizidine alkaloids (N-acet yl and N-forzyl loline) of E+ fescue was reduced from 4203 mu g/g to 3 009 and 2533 mu g/g by the 1AE+ and 5AE+ treatments, respectively. Erg ovaline was lowered from 3.77 to 1.57 mu g/g by 1AE+ and eliminated by 5AE+. Endophyte-infected treatment groups had depressed (P < 0.0001) daily feed intakes (DFI) daily weight gains (DWG), feed efficiencies ( G/F) primary antibody responses, and T cell and B cell mitogenic respo nses than endophyte-free treatment groups. Ammoniation of endophyte-in fected fescue seed improved DFI and DWG (P < 0.0001) and G/F (P< 0.05) ; however, there was no difference in performance criteria between the 1-wk and 5-wk ammoniation treatments. Endophyte-induced depressions i n immune function were not alleviated by ammoniation.