Effects Of Free Range And Cage Methods On The Main Immune Indexes Of Dagu Chicken

Dagu chicken is a kind of Liaoning local chicken with prominent feature,it has strong egg laying performance,fresh meat,and high nutritional value.At present,the market demand for Dagu chicken is growing,resulting in the original bulk feeding mode can not meet consumer demand;and,due to its large feed intake,serious damage to vegetation in the stocking area,thus,intensive cage cultivation is imperative.But in the intensive cage cultivation,the disease incidence of Dagu chicken is increased.In this paper,the difference of immunity of Dagu chicken under different feeding methods is explored to look for a reasonable feeding method to provide theoretical support for the large-scale development of Dagu chicken breeding industry.MethodsThe Dagu chickens were randomly divided into two groups: Free range group and Cage group.And the immune organs of Dagu chicken were collected respectively at 85 days age and 120 days age,for the calculation of spleen index,bursa index and thymus index;Venous blood collection,Serum separation,using ELISA method to detect the total Ig G,total Ig A and lysozyme level in the serum;Isolation of lymphocytes from spleen,and using MTT method to detect T and B lymphocyte proliferation activity;Isolation of macrophages in spleen,and using Griess method to detect the ability of macrophage to release NO.At the 7th and 60 th day age,Newcastle disease vaccine was given to Dagu chicken immunization,and at the 4th week age,randomly divided into two groups: ND free range group and ND Cage group.The immune organs of Dagu chicken were collected respectively at 85 days age and 120 days age,for the calculation of spleen index,bursa index and thymus index;Venous blood collection,Serum separation,using ELISA method to detect IL-4,IFN-γ and lysozyme level in serum;using HI experiment to detect Newcastle disease antibody level in serum;making extraction of total m RNA from blood cells,and using real-time PCR method to detect the m RNA level of IL-4,IFN-γ;Isolation of lymphocytes from spleen,and using MTT method to detect T and B lymphocyte proliferation activity;Isolation of macrophages in spleen,and using Griess method to detect the ability of macrophage to release NO.And using SPSS 17 statistical software for data analysis.ResultsIn unvaccinated state,the spleen index and bursa index of Dagu chicken in free range group at 85 days age were significantly higher than those in the cage group.And the thymus index difference between 2 groups was not significant.The ability of macrophages to release NO at 120 days of age in free range group was significantly higher than that in the cage group.And the difference in lysozyme content between the two groups was not significant.T lymphocyte proliferation activity at 120 days of age in free range group was significantly higher than that in the cage group.The proliferation of B cells showed no significant difference between these two groups.Total serum Ig G level at the 85 days age in the free range group was significant higher than that in cage group.And total Ig A level in serum at 120 days age in the free range group was significant higher than that in cage group.Under Newcastle disease vaccination status,the spleen index and bursa index of Dagu chicken in ND free range group at 85 days age were significantly higher than those in the ND cage group.And the thymus index difference between 2 ND groups was not significant.The ability of macrophages to release NO at 120 days of age in ND free range group was significantly higher than that in the ND cage group.And the difference in lysozyme content between the two ND groups was not significant.T lymphocyte proliferation activity at 85 days of age in ND free range group was significantly higher than that in the ND cage group.The proliferation of B cells showed no significant difference between these two ND groups.IFN-γ protein level and m RNA levels at 85 days age in ND free range were significant higher than those in ND cage group.The IL-4 protein level and m RNA level showed no obvious difference between these two ND groups.And,Newcastle disease antibody showed no significant difference between these 2 groups.ConclusionsCompared with cage group,the free range group could improve the immune capacity of Dagu chicken to a certain extent.However,the free range cultivation mode had little effect on the level of Newcastle disease specific antibody.