Effects Of Atmospheric Ammonia Concentration On Broiler Growth Performance And Airway Mucous Barrier

This study was conducted to investigate the effects of ammonia concentration on growth performance and meat quality of broiler. This study was divided into three parts.Experiment 1:the experiment was conducted in four chambers of the state key laboratory of animal nutrition Three hundred and twenty 21-day-old Arbor Acres broilers were divided randomly into 4 groups for different treatments, with 4 replicates in each group and 20 broilers in each replicate. Each treatment of broilers was placed in a separated, environmentally controlled chamber, and ammonia concentrations in the four chambers were metered continuously to maintain (3±3) mg/kg, (25±3) mg/kg, (50±3) mg/kg and (75±3) mg/kg, respectively. The broilers were net-rearing and provided ad libitum access to water and diets. The experiment lasted for three weeks. Broilers were slaughtered to sampling in 35 days and 42 days of age. The results showed as follows:(1) During the early period of the experiment(22-32 d), when ammonia concentration was between 50 and 75 mg/kg, ADG and ADFI of broilers was significant decreased compared with the control group(P<0.05); ammonia concentration did not significant affect F/G of broilers(P>0.05).(2) During the later period of the experiment(32-42 d), compared with the control group, ADFI of broilers was significant decreased when ammonia concentration was 25-75 mg/kg(P<0.05); ammonia concentration did not significant affect ADG and F/G of broilers(P>0.05). (3) During the whole experiment period, compared with the control group, ADG and ADFI of broilers in all three experiment group had a significant decrease(P<0.05); when ammonia concentration was 75 mg/kg, F/G of broilers was significant increased(P<0.05). (4) During the whole experiment period, compared with the control group, when ammonia concentration was 75 mg/kg, abdominal fat percentage of broilers was significant improved(P<0.05); ammonia concentration did not significant affect breast meat pH(after 24 h)、color L* value、color a* value and color b* value(P>0.05);compared with the control group, drip loss rate of breast meat in all three experiment group had a significant iecrease(P<0.05).Experiment 2:the study was conducted to investigate the effects of ammonia concentration on cytokines of serum and tracheal tissue of broiler. Design of experiments was as same as Experiment 1.The results showed that:(1) At 42-day-old, when ammonia concentration was 75 mg/kg, spleen index of broilers was significant improved(P<0.05); bursal index of broilers had a increasing trend with the improve of ammonia concentration; there was no significant difference in thymus index of four group (P0.05). (2) At 32-day-old, there was no significant difference in contents of IFN-γ、IL-1β and IL-6 of four group (P>0.05). At 42-day-old, compared with the control group, when ammonia concentration was 50 mg/kg, the contents of IL-1β in serum had a evident decrease(P<0.05); when ammonia concentration was 25 mg/kg, the contents of IL-6 in serum had a significant decline (P<0.05). Compared with 32-day-old of broilers, the contents of IFN-γ and IL-6 had a decline trend in serum of 32-day-old of broilers, however, the contents of IL-1β had a opposite trend. (3) At 32-day-old, compared with the control group, when ammonia concentration was 50 mg/kg.there was a significant increase in contents of IL-1β and decrease in contents of IL-6 in tracheal tissue(P<0.05);At 42-day-old, compared with the control group, when ammonia concentration was 75 mg/kg, the contents of IL-1β and IL-6 in tracheal tissue had a evident rise(P<0.05); Compared with 32-day-old of broilers, the contents of IFN-γ and IL-6 had a decline trend in serum of 42-day-old of broilers, however, the contents of IL-1β had a opposite trend. (4) At 32-day-old, there was no significant difference in contents of IL-4 and IL-10 in serum of four group (P>0.05); At 42-day-old, there was no significant difference in contents of IL-10 in serum of four group(.P>0.05). Compared with the experiment group which ammonia concentration is 25 mg/kg, when ammonia concentration was 50 mg/kg, the contents of IL-4 in serum had a evident increase(P<0.05); Compared with 32-day-old of broilers, the contents of IL-4 had a rising trend in serum of 42-day-old of broilers, however, the contents of IL-10 had a opposite trend. (5) At 32-day-old, there was no significant difference in contents of IL-4 and IL-10 in tracheal tissue of four group(P>0.05).At 42-day-old, compared with the control group, when ammonia concentration was 75 mg/kg, the contents of IL-4 and IL-10 in tracheal tissue had a remarkable ascend (P<0.05); Compared with 32-day-old of broilers, the contents of IL-4 had a increasing trend in tracheal tissue of 42-day-old of broilers.Experiment 3:the study was conducted to reserach the effects of ammonia concentration on broiler airway mucous barrier. Design of experiments was as same as Experiment 1. The results suggested that:(1)Compared with the control group, the contents of SOD of three experiment group had a significant decrease when ammonia concentration was 25-75 mg/kg; when ammonia concentration was 75 mg/kg, the contents of CK had a significant increase(P<0.05).(2)Compared with the control group, when ammonia concentration was 50mg/kg、75mg/kg, the expression of muc 2 had a significant increase(P<0.05).(3)Compared with the control group, the expression of claudin 1 of three experiment group had a remarkable decrease. Moreover, when ammonia concentration was 50mg/kg,75 mg/kg, the expression of claudinl have a significantly lower level than group which the ammonia concentration was 25mg/kg(P<0.05).(4) Compared with the control group, the expression of caspase 3 of three experiment group had a remarkable increase (P<0.05).