AA鸡禽流感母源抗体和免疫抗体消长变化的研究

[目的]为AA鸡的禽流感预防提供依据。[方法]用不同剂量的2种禽流感疫苗免疫8日龄AA鸡,通过血凝抑制(HI)试验研究AA鸡禽流感母源抗体和免疫抗体的消长变化。[结果]AA鸡禽流感母源抗体在1~7日龄时缓慢下降,之后迅速下降,表明其半衰期约为2 d。2种禽流感疫苗均可用于AA鸡的预防接种,免疫后15 d,免疫抗体HI效价达到保护临界值,20 d时达到峰值,然后缓慢下降,43日龄时仍在临界值以上。2种不同剂量的禽流感灭活油乳剂疫苗接种后所产生的HI抗体效价的峰值差异极显著。[结论]选用禽流感灭活油乳剂疫苗,免疫剂量为0.5 ml/只,免疫时间为8日龄,整个饲养期免疫1次,即可预防商品代AA鸡禽流感。     

感染法氏囊病毒雏鸡新城疫2次免疫后免疫器官组织的免疫学变化

研究了１日龄感染法氏囊病毒（ＩＢＤＶ）雏鸡新城疫（ＮＤ）２次免疫及强毒攻击后免疫器官组织中浆细胞、酯酶阳性Ｔ细胞（ＴＡＮＡＥ＋）、巨噬细胞（ＭΦ）和淋巴细胞数量的动态变化，结果表明，１ＢＤＶ感染鸡中枢及外周免疫器官以及呼吸道、消化道局部免疫组织对ＮＤ苗的２次免疫应答具有明显的增强作用，并提示ＢＤＶ所致的免疫抑制不是不可逆的，但不能完全恢复到正常免疫应答水平。     

Enhancing Stability and Mucoadhesive Properties of Chitosan Nanoparticles by Surface Modification with Sodium Alginate and Polyethylene Glycol for Potential Oral Mucosa Vaccine Delivery

Background: The present study aimed to fabricate surface-modified chitosan nanoparticles with two mucoadhesive polymers (sodium alginate and polyethylene glycol) to optimize their protein encapsulation efficiency, improve their mucoadhesion properties, and increase their stability in biological fluids. Method: Ionotropic gelation was employed to formulate chitosan nanoparticles and surface modification was performed at five different concentrations (0.05, 0.1, 0.2, 0.3, 0.4% w/v) of sodium alginate (ALG) and polyethylene glycol (PEG), with ovalbumin (OVA) used as a model protein antigen. The functional characteristics were examined by dynamic light scattering (DLS), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM)/scanning transmission electron microscopy (STEM). Stability was examined in the presence of simulated gastric and intestinal fluids, while mucoadhesive properties were evaluated by in vitro mucin binding and ex vivo adhesion on pig oral mucosa tissue. The impact of the formulation and dissolution process on the OVA structure was investigated by sodium dodecyl-polyacrylamide gel electrophoresis (SDS-PAGE) and circular dichroism (CD). Results: The nanoparticles showed a uniform spherical morphology with a maximum protein encapsulation efficiency of 81%, size after OVA loading of between 200 and 400 nm and zeta potential from 10 to 29 mV. An in vitro drug release study suggested successful nanoparticle surface modification by ALG and PEG, showing gastric fluid stability (4 h) and a 96 h sustained OVA release in intestinal fluid, with the nanoparticles maintaining their conformational stability (SDS-PAGE and CD analyses) after release in the intestinal fluid. An in vitro mucin binding study indicated a significant increase in mucin binding from 41 to 63% in ALG-modified nanoparticles and a 27–49% increase in PEG-modified nanoparticles. The ex vivo mucoadhesion showed that the powdered particles adhered to the pig oral mucosa. Conclusion: The ALG and PEG surface modification of chitosan nanoparticles improved the particle stability in both simulated gastric and intestinal fluids and improved the mucoadhesive properties, therefore constituting a potential nanocarrier platform for mucosal protein vaccine delivery.     

Influence of size, age and maternal condition on the oocyte dry weight of Argentine hake (Merluccius hubbsi)

Effects of maternal age–size and condition on oocyte dry weight were analysed for Merluccius hubbsi. Samples of mature females were collected in the Patagonian spawning area during 10 research surveys carried out between 2000 and 2005. Dry weight of 50 hydrated oocytes ranged from 0.80 to 1.90 mg. Relationships of this variable with total length and age were best described by a logarithmic model during the spawning peak. At the beginning and at the end of the reproductive season no significant relationship between these variables was observed, but a decrease in egg dry weight was detected during the spawning period. In general, young spawners (≤5-year-old) showed more variability in egg dry weight, which was associated with a reproductive season shorter than that of old females. Relative condition factor did not shows a significant relationship with oocyte dry weight, and mean values of this index were similar for different months of the spawning seasons analysed.     

Assessment of vaccination strategies against highly pathogenic avian influenza in China

Vaccination for highly pathogenic avian influenza (HPAI) has been implemented in China for a decade, however, the virus is still present in poultry. A series of recombinant vaccines, Re-1 to Re-7, have been developed and used, and Re-8 will also be used in clinical settings to prevent the prevailing flu strains. The question remains, when can China eradicate the disease? Here, we review the epidemiology of H5 HPAI along with the development, usage and problems of vaccines. Further suggestions for controlling the disease in China are provided.     

Chickens hyperimmunized with Escherichia coli J5 strain are protected against experimental challenge with Escherichia coli O78 serotype

Veterinary Research Communications -     

Associations between green space,air pollution and birthweight in Sydney Metropolitan Area,Australia

Growing number of evidence have reported that exposure to air pollution was associated with unfavourable birth outcomes while increased exposure to green spaces was associated with better birth outcomes. However, the effect of interactions between air pollution and green spaces on pregnancy outcomes remain unclear. Using the data on all the live births recorded in Sydney between 2016 January and 2017 December, we built up multilevel linear and logistic regression models with random intercepts for statistical area level 2 (SA2) to examine the association between residential levels of air pollution (NO2, PM2.5, SO2 and O3) and pregnancy outcomes including birthweight, low birthweight, and preterm birth. This was followed by assessment of potential effect modification by green space quantity by fitting 2-way interaction term between each air pollutants and green space quantity separately. Furthermore, building on the 2-way interaction term, we explored 3-way interactions by adding area level socio-economic status and population density. Higher levels of PM2.5, NO2 and SO2 were statistically significantly associated with decrease in birthweights (p < 0.05) in the adjusted models. We observed statistically significantly association between the lower risks of preterm birth and higher levels of NO2 in the adjusted models (p < 0.05). However, none of the other air pollutants were statistically significantly associated with the odds of low birthweight and preterm birth. In the adjusted models, green space quantity was statistically significantly associated with reduced odds of preterm birth (p < 0.05). The results for birthweights were in the same direction (p < 0.05) however, some of these associations did not remain statistically significant after adjusting the models for air pollution. In general, no associations were found for low birthweight. Statistically significant 2-way interactions between green space quantity and NO2, PM2.5 and SO2 levels indicated that association between moderate levels of NO2, PM2.5 and birthweight weakened in the greener areas (>20 %) especially in the affluent and densely populated areas while the effect of SO2 did not differ consistently across green space levels with benefit of exposure to the greenest areas (>40 %) was evident, yet not statistically significant. Our findings suggest that increasing green spaces in cities may help supporting a healthy start in life by decreasing harms of moderate levels of air pollution. Replication in different contexts and consideration of potentially contrasting results with different types of green space is warranted.