| This experiment used climate chambers to simulate different ammonia concentration and investigate the effect of different ammonia concentration on performance,physiological biochemical indexs,immune and antioxidant function of cattle.To provides a reference for sustainable development of cattle breeding and the study of harmful gas limits.In this study,Sixteen 12 months of age Qinchuan cows with closed body weight?mean BW 220±5 kg?and good health,obtained from the international beef cattle improvement center?Yangling in Xianyang,China?,and were randomly divided into four treatment groups?7.4 m×4.2 m×2.7 m?.Each treatment group have 4 cattle,and each cattle is 1repetition.The concentrations of NH3 in each treatment were set to 5,15,30 and 45 mg/m3,respectively,and environmental indexes were controlled at the same level except for the NH3 concentrations in each chamber.The whole trial period have 40 days,of which advanced experiment period has 10 days,the trial period have 30 days.Detection indicators mainly include growth performance?ADG,ADFI,F/D?physiological index?heart reat,breathe,rectal and temperature?.Biochemical indexs?ALT,AST,AN,COR,ALP,BUN et al?,immune indices?lgA?lgG?lgM?,Cytokines?IL-1??IL-6?TNF-??IL-4?IL-10?IFN-??,Antioxidant ability?T-AOC?GSH-PX?SOD?CAT?MDA?.The main results were as follows:1?The effects of different NH3 concentration on growth performance of cattle.The resulted showed that NH3 stress significant reduced ADG and ADFI?P<0.05?,significant raised F/D?P<0.05?,However,there were no significant effect on water consumption.2?The effects of different NH3 concentration on physioldgical and biochemical indexes of cattle.The resulted showed that NH3 treatment had no significant effect on the rectal temperature of cattle,but with the increase of NH3 concentration,the respiratory rate of cattle decreased significantly?P<0.05?and the heart rate increased significantly?P<0.05?.The content of TP,ALB,GLO,BUN,CRE,GLU,ALT,AST,LDH was increased with the increase of NH3 concentration compared with the control group,and reached a significant level at 45mg/m3?P<0.05?,while the other groups were not significantly different.Compared with the control group,the contents of TC,TG and ALP showed an upward trend,but there were no significant at each groups.During the whole trial period,the contents of CK and CK-MB first increased and then declined.Compared with the control group,NH3 treatment significantly increased the blood ammonia content in each treatment group?P<0.05?,and during the whole experiment period,the blood ammonia content increased first and then decreased.NH3 exposure had no significant effect on the contents of,chlorine and calcium except for calcium ions?P<0.05?.However,the contents of serum Na,Cl,Ca showed an increasing trend during the whole period of the experiment,while the contents of Cl decreased with the increase of NH3 concentration.3?The effects of different NH3 concentration on immune function of cattleThe results showed that compared with the control group,NH3 treatment significantly reduced the content of lgA and lgM?P<0.05?,but there was no significant effect on the content of lgG in each treatment group.The contents of IL-1?,TNF-?,IFN-?and IL-10 in serum decreased with the increase of NH3 concentration.The contents of IL-1?,IFN-?in serum decreased significantly at 30 and 45mg/m3?P<0.05?,TNF-?decreased significantly at45mg/m3?P<0.05?,but IL-10 had no significant effect in each treatment group.The serum IL-6,IL-4 content increased with the increase of NH3 concentration,and reached a significant level at 30 and 45mg/m3?P<0.05?.4?The effects of different concentrations of NH3 on antioxidation ability of cattle.The results showed that the content of T-AOC and GSH-PX decreased with the increase of NH3 concentration compared with the control group,and reached significant level at 30and 45 mg/m3?P<0.05?.The content of SOD and CAT were increased with the increased of NH3 concentration.But there were no significant difference in each group.Compared with the control group,the MDA content increased significantly?P<0.05?,when the NH3concentration was 30mg/m3,but there was no significant difference between the other groups.In conclusion,NH3 exposure reduced the production performance of cattle,caused damage to related organs in vivo,reduced the immune and antioxidant capacity of the body,and induced inflammatory reaction.It is suggested that the concentration of NH3 in large-scale beef barn should not be higher than 15 mg/m3. |
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