Fig. 1. Least squares means of ammonia emission rates from growing-finishing pigs. In Trial 1 (n = 683, SEM = 0.43 mg min^–1; P = 0.098), pigs were fed a control corn and soybean meal diet (C), a reduced crude protein diet containing Lys (L), and a further reduced crude protein diet containing Lys, Met, Thr, and Trp (LMTT). In Trial 2 (n = 600, SEM = 0.27 mg min^–1; diet P = 0.885), pigs were fed a diet containing Lys and no yucca (L + 0), a diet with Lys and 62.5 mg kg^–1 of a yucca product (L + 62.5), and a diet with Lys and 125 mg kg^–1 of a yucca product (L + 125). Means without a common superscript letter differ (P < 0.05).