| With the development of intensive and large-scale livestock & poultry production systems, animal health and welfare have attracted extensive attention. It has been estimated that the major factors affecting animal production benefits include genetic performance, nutritional condition, and environmental quality, they have contribution rates of 45%, 30%, and 25%, respectively. Air quality is an important index of the environmental quality, while microbial aerosols are the main indications of the environmental quality. It is obvious that, the sanitary environmental management of a livestock & poultry house is very important. To better understand the effect of different breeding environments on broilers'immune function, in this study, 320 one-day-old healthy Arbor Acres(AA) broilers were randomly divided into two groups, i.e., Experimental Group(EG) and Control Group(CG), and bred in the chicken houses of different sanitary environmental management conditions. The concentrations of aerobic bacteria, fungi, and endotoxins in the air of the chickens'houses were determined periodically, and meanwhile, Newcastle Disease antibody(ND-Ab) levels,immune organ indexes of broilers,serum lysozyme content,WBC and peripheral blood T lymphocyte conversion ratio were detected. The experiment was done twice (Trial 1 and Trial 2).1. Results of collection and culture of airborne aerobic bacteria showed, in trial 1, the airborne aerobic concentrations of test group and control group were in the range of 2.9-5.12×10~6 CFU/m~3 air and 0.57-1.83×10~6 CFU/m~3 air, respectively; in trial 2, the airborne aerobic concentrations of test group and control group were in the range of 2.76-10.99×10~6CFU/m~3 air and 0.86-1.74×10~6CFU/m~3 air, respectively.2. Results of collection and culture of airborne fungi showed, in trial 1, the airborne fungal concentrations of test group and control group were in the range of 2.8-5.6×10~5 CFU/m~3 air and 0.72-1.1×10~5CFU/m~3 air, respectively(P<0.05); in trial 2, the airborne fungal concentrations of test group and control group were in the range of 0.27-1.21×10~5 CFU/m~3 air and 0.11-0.37×10~5 CFU/m~3 air, respectively(P<0.05).3. Results of collection and quantification of airborne endotoxins showed, in trial 1, the airborne endotoxin concentrations of test group and control group were in the range of 2.5-16×10~3 EU/m~3 air and 2.4-3.1×10~3 EU/m~3 air, respectively(P<0.05); in trial 2, the airborne endotoxin concentrations of test group and control group were in the range of 0.8-17.07×10~3 EU/m~3 air and 0.4-2.13×10~3 EU/m~3 air, respectively(P<0.05).4. Results of measurement of ND-Ab levels showed, in the prophase of the two trials, there was no significant difference between the two groups. However, in Trial 1, the ND- Ab levels of the control group were significantly higher than those of the test group on days 35, 42, and 49(P<0.05); in Trial 2, the ND-Ab levels on days 28, 35, and 42 were significantly higher in the control group than in the test group, and there was very significant difference of ND-Ab levels between the two groups on day 49(P<0.01).5. The results of measurement of immune organ indexes showed that, In Trial 1 ,on day 21, there were minimal differences of spleen indexes, BF indexes, and thymus indexes of the broilers between the two groups; on day 35, the thymus indexes of the control group were significantly higher than those of the test group(P<0.05); on day 49, the spleen indexes of the control group were significantly higher than those of the test group(P<0.05), while there was very significant difference of thymus indexes between the two groups(P<0.01), but no significant difference in BF indexes(P>0.05); in Trial 2, on the three sampling dates, the spleen indexes and the BF indexes of the control group were higher than those of the test group; however, there was no significant difference(P>0.05). Nevertheless, the results through comparison of the thymus indexes between the two groups were similar to those of Trial 1.6. The results of measurement of serum lysozyme content showed that, in Trial 1, the serum lysozyme contents of the test group were higher than those of the control group on days 14, 21, 28, 35, while the serum lysozyme contents of the test group were lower than those of the control group on days 42, 49;in Trial 2, the serum lysozyme contents of the test group were higher than those of the control group on days 14, 21, while the serum lysozyme contents of the control group were higher than those of the test group on days28,35, 42, 49, and the difference was significant on day 49.7. The results of measurement of WBC showed, both the two trials, the number of WBC of the experimental group are slightly higher than the control group in the early and slightly lower at later time. But the difference was not significant (P>0.05).8. The results of peripheral blood T lymphocyte conversion ratio of broilers showed, both in the two trials, the peripheral blood T lymphocyte conversion ratio of the experimental group are lower than the control group, the difference was significant at 35d,42d in Trial 1 and 42d in Trial 2.The results showed that, poor quality of a chicken house resulted in increase of microbial aerosol level, and negatively affected broiler body's immune function, it is a key point for healthy breeding to do well breeding sanitary management of animal houses.
|
PDF Full Text Request