Effects of reducing dietary crude protein on growth performance, odor gas emission from manure and blood urea nitrogen and IGF‐1 concentrations of serum in nursery pigs

Two experiments were conducted to investigate the effects of reducing dietary crude protein on growth performance, odor gas emission from manure and blood urea nitrogen and IGF‐1 concentrations of serum in nursery pigs. In experiment 1, the dietary treatments were (i) CON (CP 19.5%) and (ii) T1 (CP 16.0%). In feces samples, NH 3 , H 2 S, acetic acid and butyric acid emissions during the T1 treatment were lower than during the CON treatment ( P < 0.05). In feces‐urine samples, NH 3 emission during the T1 treatment was lower than during the CON treatment ( P < 0.05). In experiment 2, 28 crossbred (Landrace × Yorkshire × Duroc) pigs (13.58 ± 0.10 kg) were used for a 42‐day growth trial. Throughout the entire experimental period, ADG and ADFI of the CON treatment were higher than the T1 treatment ( P < 0.05). On day 14, N digestibility in pigs fed the CON diet was higher than that of pigs fed the T1 diet ( P < 0.05). On days 28 and 42, DM digestibility of the CON diet was greater than the T1 treatment ( P < 0.05). On dat 42, serum BUN concentration of pigs fed the CON diet was higher than that of pigs fed the T1 diet ( P < 0.05). In conclusion, these results indicate that reduction in dietary CP concentration decreased NH 3 , H 2 S and VFA emissions in feces and growth performance in nursery pigs.