The expression patterns of 5-hydroxytryptamine(5-HT),gastrin(Gas),β-endorphin(End),somatostatin(SS),vasoactive intestinal peptide(VIP),glucagon(Glu) and neuropeptide Y(NPY)-positive cells in the duck thymus were studied by the immunohistochemical method associated with image analysis.The result shows that these 7 kinds of neuroendocrine cells with strong intensity were differentially detected in the duck thymus.The End-positive cells were abundantly expressed in the thymic cortex,whereas the Gas,5-HT,SS,VIP,Glu and NPY ones were more frequent in the medullary and around the corticomedullary junction.Except Glu,the other 6 kinds of neuroendocrine substances with various intensity were expressed in the cells of thymic corpuscles.The observation demonstrated that the duck thymus is not only a primary lymphatic organ,but also has important neuroendocrine functions.The End-positive cells in the thymus may play crucial roles in the development of immature T-lymphocytes.The neuroendocrine cells with a predominant distribution in the medulla and around the corticomedullary junction might facilitate exerting their influence via an endocrine,autocrine or paracrine pathways on the function of mature T-cells.The possible roles of thymic corpuscles are also discussed.

By using routine H. E method and measuring the absolute weight and growth index of thymus and ANAE positive ratios, 1 to 49 days Tianfu duckling were selected to study the changing trends in the normal development of the thymus. The results are as follows:the thymus of duckling develops slowly from 1 to 14 days,and quickly from 21 to 35 days,then steadily from 35 to 49 days. By the 28th day,most T-lymphocytes have well differentiated and the thymus has reached its maturation. There are three types of thymie corpuscles whose functions have been discussed.

150-day-old Tianfu ducklings were divided into three groups,and fed with diets as follows :Zn deficient (22. 9 mgZn per kg diet),controls(100 mg Zn per kg diet) and Zn toxic (1 300 mg Zn per kg diet) for seven weeks (Zn deficiency,ZD)or four weeks (Zn toxieity,ZT). The ANAE+ positive ratios of the peripheral blood T-lymphocytes were much lower (P＜0.01 ) in Zn deficient and toxic groups than in the control group. The results showed that Zn deficiency and toxicity would suppress the development of T-lymphocytes and reduce the peripheral blood T-lymphocyte populations. Potential mechanisms underlying these observations are also discussed.

The experiment was conducted to examine the effect of zinc toxicity on the peripheral blood T-lymphocyte by the method of flow cytometry(FCM) and ANAE.200 one-day-old Avian broilers were divided into four groups,and fed with the diets as follows:①control group(Zn 100 mg/kg diet) and ② zinc toxic groups(Zn 1 500 mg/kg diet,zinc toxic group Ⅰ;Zn 2 000 mg/kg diet,zinc toxic group Ⅱ;Zn 2 500 mg/kg diet,zinc toxic group Ⅲ) for seven weeks.The ANAE positive ratios of the peripheral blood T-lymphocytes were much lower in the three zinc toxic groups than that in control group at 7 weeks of age.CD4+ T cell numbers were reduced from 2 to 7 weekds of age in zinc toxic group Ⅲ and from 6 to 7 weeks of age in zinc toxic group Ⅱ,as compared with that of control group.The numbers of CD8+ T cell decreased at 2 and 4 weeks of age in zinc toxic groups Ⅱ and Ⅲ,and at 7 weeks of age in zinc grups Ⅰ and Ⅲ.CD4+/CD8+ ratio was higher at 2 and 4 weeks age,and lower at 6 and 7 weeks of age in zinc toxic groups Ⅰ,Ⅱ and Ⅲ than in control group.The results showed that zinc toxicity would suppress the development of T-lymphocytes and reduce the peripheral blood T-lymphocyte populations.Potential mechanism underlying these observations are also discussed.

The experiment was conducted to examine the effect of copper toxicity on the peripheral blood T-lymphocyte using the flow cytometry(FCM) and ANAE.180 one-day-old Avian broilers were divided randomly into three groups,and fed diets as follows:(1)Controls(Cu 11.97 mg/kg diet) and (2)copper toxic(Cu 650 mg/kg diet,copper toxic group Ⅰ;Cu 850 mg/kg diet,copper toxic group Ⅱ) for six weeks.The ANAE positive ratios of the peripheral blood T-lymphocytes were much lower in the two copper toxic groups than in control group from 1 to 6 weeks of age(P＜0.05 or P＜0.01).Also,there was significant difference between copper toxic groups Ⅰ and Ⅱ at 1,3,5 and 6 weeks of age(P＜0.05 or P＜0.01).CD+4 T cell numbers reduced from 2 to 6 weeks of age in both copper toxic group Ⅰ and copper toxic group Ⅱ as compared with those of control group(P＜0.05 or P＜0.01).At the same time,there was significant difference between copper toxic groups Ⅰ and Ⅱ at 6 weeks of age(P＜0.05).But the numbers of CD+8 T cell were not varied from 2 to 6 weeks of age in copper toxic groups Ⅰ and Ⅱ in comparison with those of control group(P＞0.05).The CD+4/CD+8 ratio was lower from 2 to 6 weeks of age in copper toxic groups Ⅰ and Ⅱ than in control group.The results showed that copper toxicity could suppress the development of T-lymphocytes and reduce the peripheral blood T-lymphocyte populations.Potential mechanisms underlying these observations are also discussed.

By measuring the absolute weight and growth index of the bursa of Fabricius and using routine H.E method,the growth and histological development of the bursa in 1 to 49 days duckling were studied.The results showed that the absolute weight of the bursa increased as the ducklings grew.The growth index of the bursa reached its peak at 21 days.The height and width of both the large plica and projection formed by the follicle-associated epithelium(FAE)enlarged gradually,the same as the lymphoid follicle area and cortex width.The results indicated that the bursa of Fabricius in duckling develops slowly from 1 to 14 days,and quickly from 14 to 35 days(especially from 21 to 28 days),then steadily from 35 to 49 days.Histologically,the duckling bursa has approached its maturation by the 28th day.

AIM:To study whether the pulmonary infection of Escherichia coli (E.coli) interferes the glu-colipid metabolism in high-fat diet-induced obese mice.METHODS:High-fat diet-induced obese mice (n=48) and nor-mal chow-fed control mice ( n=48) were intranasally infused with 40 μL fluid containing 4 ×109 CFUs E.coli.The ser-um, periepididymal adipose tissue and liver were obtained at 0 d, 1 d, 2 d, 3 d and 4 d after infection.The body mass, periepididymal adipose tissue and liver were weighed , and the levels of fasting blood glucose (FBG), fasting blood insulin ( FINS) , free fatty acid ( FFA) and very-low-density lipoprotein ( VLDL) were measured by ELISA .The serum total cho-lesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol ( LDL-C) , and hepatic TG contents were detected , and the hepatic steatosis was observed under microscope with oil red O staining.RESULTS:Compared with day 0, the body mass, fat mass and fat index were decreased significantly from day 1 to day 4 after infection (P<0.05).The levels of FBG, FINS and HOMA-IR were apparently raised from day 2 to day 4 af-ter infection (P<0.05).The contents of serum FFA, TG and VLDL were increased markedly from day 1 to day 4 after in-fection (P<0.05).However, the concentrations of serum TC, LDL-C and HDL-C were decreased obviously from day 1 to day 3 ( P<0.05 ) .The liver mass , liver index and TG content were significantly increased from day 1 to day 4 ( P<0.05 ) .Consistently , the lipid droplet accumulation in the liver cells was increased obviously at day 2 and day 4 after infec-tion.Compared with control group , except the levels of serum TC , LDL-C and HDL-C in obese group substantially de-creased, the other indexes were increased by different degrees during the whole experiment period (P<0.05).CONCLU-SION:Pulmonary infection of Escherichia coli exacerbates the disorder of glucose and lipid metabolism in high-fat diet-in-duced obese mice , which contributes the development of insulin resistance and hepatic steatosis .

In this study, apoptosis was induced by new type gosling viral enteritis virus (NGVEV) in experimentally infected goslings is reported in detail for the first time. After 3-day-old goslings were orally inoculated with a NGVEV-CN strain suspension, the time course of NGVEV effects on apoptotic morphological changes of the internal tissues was evaluated. These changes were observed by histological analysis with light microscopy and ultrastructural analysis with transmission electron microscopy. DNA fragmentation was assessed with a terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) assay and DNA ladder analysis. A series of characteristic apoptotic morphological changes including chromatin condensation and margination, cytoplasmic shrinkage, plasma membrane blebbing, and formation of apoptotic bodies were noted. Apoptosis was readily observed in the lymphoid and gastrointestinal organs, and sporadically occurred in other organs after 3 days post-infection (PI). The presence and quantity of TUNEL-positive cells increased with infection time until 9 days PI. DNA extracted from the NGVEV-infected gosling cells displayed characteristic 180~200 bp ladders. Apoptotic cells were ubiquitously distributed, especially among lymphocytes, macrophages, monocytes, and epithelial and intestinal cells. Necrosis was subsequently detected during the late NGVEV-infection phase, which was characterized by cell swelling, plasma membrane collapse, and rapidly lysis. Our results suggested that apoptosis may play an important role in the pathogenesis of NGVE disease.
*Adenoviridae/classification/pathogenicity ; Adenoviridae Infections/pathology/*veterinary/virology ; Animals ; *Anseriformes ; *Apoptosis ; Bird Diseases/*virology ; DNA Fragmentation ; Enteritis/*veterinary/virology ; Epithelial Cells/cytology/virology ; In Situ Nick-End Labeling ; Intestines/cytology/virology ; Leukocytes/cytology/virology ; Lymphoid Tissue/cytology/virology ; Macrophages ; Microscopy, Electron, Transmission