Supplemental L-arginine attenuates pulmonary hypertension syndrome (ascites) in broilers.

The incidence of pulmonary hypertension syndrome (PHS; ascites) was evaluated in two experiments using broiler breeder male by-product chicks exposed after 3 wk of age to cool environmental temperatures (10 to 15 C). In Experiment 1, 3- to 6-wk-old birds were fed a grower diet to which 0 (Control), .25, .5, or 1% supplemental L-arginine HCl had been added. During Weeks 7 to 8, all groups in Experiment 1 were fed a finisher diet containing no supplemental arginine. In Experiment 2, the Control group received no supplemental arginine, a second group was fed a grower diet supplemented with 1% L-arginine HCl (Weeks 3 to 6), and a third group was fed grower and finisher diets supplemented with 1% L-arginine HCl (Weeks 3 to 8). Cumulative PHS mortality was significantly reduced by 1% L-arginine HCl on Days 34 to 46 in Experiment 1. When data from all birds fed grower or finisher diets supplemented with 1% L-arginine HCl were pooled in Experiment 2, cumulative PHS mortality was marginally lower (P = .065) than for the Control group. Supplemental L-arginine HCl had no effect on final body weights, weight gain, or feed conversion in either experiment. Neither body weight on Day 1 or 21 nor net weight gain from Days 1 to 21 determined susceptibility to PHS during the subsequent grower and finisher intervals in either experiment.(ABSTRACT TRUNCATED AT 250 WORDS)