| dc.description.abstract | Two experiments were conducted to evaluate the effects of chromium propionate (CP)
and butyric acid-zinc complex (BAZ) on broiler performance and processing yields. Experiment
1 evaluated CP inclusion on broiler growth performance when reared on used litter. A total of
36 pens with 720 chicks were randomly assigned to 3 treatments (12 reps/treatment; 20 birds/
treatment): control (no CP), 100 ppb, and 200 ppb CP. Experiment 2 evaluated CP combined
with BAZ on performance, carcass yield, and meat quality when fed to broilers reared in
simulated heat stress. A total of 1680 broilers (15 replicates per treatment and 28 bird/replicate)
were raised in a completely randomized 2x2 block design (CRBD) fed CP at (0 or 200 ppb) and
BAZ at 0 or 132 g butyric acid and 55 g of zinc. . Chicks were placed into 60 pens based on
body weight. Broilers were kept in a tunnel-ventilated house during July and August to simulate
summer heat stress. For both experiments, feed intake and body weight were collected biweekly,
and at the termination of the trial a subsample of birds were processed to determine processing
weights, yield percentage, and woody breast/white striping presence and severity scoring. On d
42 in experiment 2, 30 birds per treatment/2 birds per pen were sampled to determine plasma
corticosterone levels. Results from experiment 1 indicate the addition of 200 ppb CP
significantly improved feed conversion ratio (FCR) through d 42 (1.61 vs 1.58) and carcass yield
by 1.48% (P=0.006) compared with the control diet. In addition, the inclusion of 200 ppb of CP
significantly increased breast weigh by 41g (P=0.029). Therefore, the dietary inclusion of CP can
be advantageous on broiler growth performance and processing yields. Results from experiment
2 indicated improvements (P<0.05) with the addition of CP at 200ppb in feed conversion ratio,
increased breast meat yield, and decreased total mortality. The diet containing the combination
of BAZ and CP reduced (p<0.05) average woody breast score. In conclusion, these data confirm
the ability of CP to improve performance and yield in broilers exposed to environmental and heat
stress. | en |
