Simulation of maternal immunity by inoculation of immune yolk preparations into the yolk sac of 1-day-old chickens.

Yolk harvested from eggs laid by hens hyperimmunized with killed Newcastle disease virus (NDV) was inoculated into the yolk sac of 1-day-old specific-pathogen-free (SPF) chickens. Serum hemagglutination-inhibition antibody titers reached maximum levels 1 to 4 days after yolk inoculation and declined at a rate similar to that reported for naturally acquired maternal antibody. Expected levels of immune interference were observed when yolk-inoculated chickens were vaccinated with a conventional oil-emulsion NDV vaccine. These results show that yolk-sac inoculation with yolk antibody is a suitable approach for producing maternally immune chickens for laboratory studies.     

Dynamics of yolk sac resorption and post-hatching development of the gastrointestinal tract in chickens, ducks and geese

Under similar environmental conditions, 100 male Shaver-Starbro hybrid chickens, 100 male Mulard cross-line ducklings and 100 male Landaise goslings kept in 30 metabolic cages from the first day of life (10 birds of each species separately per cage) were chosen for the study. The animals were fed semi ad libitum diets with crude protein content and energy density similar to that used for poultry species, avoiding feed residues. During the first 21 days of life they received starter diets and from day 22 to 42 grower diets. Maize accounted for 23-40% and barley constituted 10-18%. Wheat accounted for 20.0% in starter diets and 10-18% in grower diets. Resorption of yolk sac residues, performance, development of the intestinal tract in young chickens, ducklings and goslings were assessed. During the first 5 days of life intensive absorption of yolk sac ingredients was observed. On day 7, residues of the yolk sac were found in more than 30% of chickens compared with approximately 10% in geese. In ducklings residues of the yolk sac were not found. On day 16 unabsorbed yolk sacs were found in approximately 10% of chickens. Liver and pancreas weighed the highest in geese and in ducks; in chickens the weight of these organs was significantly lower (p < 0.01). The relative values calculated to 100 g of metabolic body weight show that the average small intestine in chickens was significantly longer (p < 0.01) than in ducks or geese. The intestinal tract developed earlier in the chicken than in the water fowl.     

新生雏鸡卵黄囊阶段的营养研究进展

雏鸡出壳后在营养上经历了由完全依靠内源性养分 (卵黄囊 )到依赖外源性饲料养分的一个转折期。 Kuenzel等（ 1977）报道，刚出壳的雏鸡， 1日龄时能量代谢就由卵黄脂类供给能量转向主要由外源性碳水化合物饲料供给。在雏鸡出壳时，卵黄囊从蛋腔中转入胚胎的腹腔内。在那里，卵黄囊的一端通过血管束与脐部相连，出壳后逐渐萎缩， 3～ 4日龄时与脐部脱离，另一端通过卵黄管直接开口于空肠。出壳时卵黄囊的重量约占体重的 13％～ 14％。 Cheville和 Coignoal（ 1984）发现，大约有 20％的卵黄物质剩余在卵黄囊中，这些物质将在出壳后一周内…     

雏鹌鹑葡萄球菌卵黄囊感染报道

近几年来，江西部分鹌鹑养殖场多次发生雏鹌鹑在出雏房内大面积发病死亡的病例。2008年4月，江西农业大学动科院预防兽医实验室对江西省南昌县某鹌鹑养殖场雏鹌鹑在出雏房发病情况及临床症状进行调查，剖检死亡雏鹌鹑并且从死亡雏鹌鹑肝脏和卵黄液中分离到两株细菌。通过对两株细菌的形态、培养特性观察和生化鉴定以及利用分离到的细菌进行人工雏鹌鹁发病复制实验，最终诊断为葡萄球菌感染。现报道如下。     

Serotyping and virulence genes detection in Escherichia coli isolated from fertile and infertile eggs, dead-in-shell embryos, and chickens with yolk sac infection

Escherichia coli is a common avian pathogen mainly associated with extraintestinal infections such as yolk sac infection (YSI). The aim of this study was to determine the serotypes and the presence of some virulence genes of E. coli strains isolated from different samples in a vertically integrated poultry operation in Mexico. Two hundred sixty-seven E. coli isolates from different samples were serotyped using rabbit serum against the 175 somatic (O) and 56 flagellar (H) antigens of the typing schema. Virulence genes were determined by colony blot hybridization, using DNA probes for st, eae, agg1, agg2, bfp, lt, cdt, slt, and ipaH diarrhea-associated virulence factors. The serogroup of 85% of the strains was determined; O19 (12%), 084 (9%), 08 (6%), and 078 (5%) were the most common. Using the complete antigenic formula (O and H), O19:NM (n = 31) was the serotype most frequently isolated from dead-in-shell embryos and in broilers that had died on the fourth, fifth, sixth, and seventh days after hatch. One hundred ten strains (41.2%) hybridized with one or more of the used probes. Of these, ipaH (72%), eae (30%), and cdt (27%) were the most common. Considering the origin of the respective isolates, 40% of the broiler farm strains were positive for at least one probe. Results show that some avian E. coli strains isolated in Mexico are included in avian pathogenic E. coli serotypes not previously reported, suggesting that they could be specific for this geographic area. The wide distribution of the ipaH gene among nonmotile strains suggests that this invasiveness trait could be important in YSI pathogenesis. On the other hand, some other genes could contribute to E. coli virulence during YSI.     

Yersinia pseudotuberculosis recovered from the faeces of clinically healthy deer

Extract

Sir:— A recent paper by Henderson and Hemmingsen(1) reported the recovery of Yersinia pseudotuberculosis from the faeces of 5 of 3810 (0.13%) clinically healthy deer in a national survey conducted on 122 farms. The isolates were obtained from animals on four (3.27%) different farms. The authors concluded on the basis of these results and unpublished data that Y. pseudotuberculosis was only rarely recovered from faeces of healthy deer.     

Histochemical observations on the enzymes of chicken yolk sac membrane

In the endodermal cells of the yolk sac membrane of chicken embryos incubated for 12 to 18 d, the activity of glucose‐6‐phosphatase (G‐6‐Pase) was high, the activity of acid phosphatase (Acid Pase) was moderate, the activities of lactate dehydrogenase (LDH) and of glyceraldehyde‐3‐phosphate dehydrogenase (G‐3‐PDH) were low, and succinate dehydrogenase (SDH) and alkaline phosphatase (Alk Pase) activities were not detected. On the day before hatching, however, SDH became evident with low activity, and the activities of Acid Pase, LDH and G‐3‐PDH increased and remained higher until the day after. Five days after hatching, there were marked decreases in the activities of all the enzymes except SDH. Alk Pase was not detected at any time. The function of the yolk sac endo‐derm in the absorption of yolk is discussed in the light of these observations.     

Calcium in the turkey yolk sac during late development and postembryonic involution

Yolk sacs (YS) were examined by gross, histochemical, and electron microscopic techniques from incubation day 12 to 10 days of age. Weights were maximal at 22 days of incubation and declined markedly thereafter; by 7 days of age, the yolk was completely absorbed. Endodermal cells of YS epithelium were highly polar with nuclei, mitochondria, and glycogen in basal areas and lipid globules and intralysosomal yolk granules near luminal surfaces. Yolk laminar spherules were first seen at day 16 of incubation. They increased progressively with incubation and disappeared rapidly after hatching. Spherules stained for calcium, glycosaminoglycans, and alkaline phosphatase in late incubation and were considered calcium storage structures. Histochemical evidence of intracellular calcium loading of yolk matrix (from 18 days of incubation until 5 days of age) suggested a specific calcium transport function of YS epithelium.     

Isolation and partial characterisation of bacteria recovered from abscesses of normally slaughtered pigs

One hundred and one pig abscesses of different localisation were examined. Bacteria were re-covered from all abscesses. In 6’8 abscesses a mixed aerobic and anaerobic flora was found. In 22 abscesses solely aerobes and in 11 solely anaerobes were found. Gorynebaoterium pyogenes and Fuso-bacterium necrophorum were found in 61 and 45 abscesses, respectively. Hemagglutination litres of G. pyogenes strains were higher with pig erythrocytes than with sheep erythrocytes. Three of 4 isolates of Staphylococcus aureus produced enterotoxin type A.Key words: pig abscess, Corynebacterium pyogenes, Fuso-bacterium necrophorum, hemagglutination     

Bacterial and mycoplasmal flora of the healthy camelid conjunctival sac

Healthy conjunctival sacs of 88 animals of 3 species of captive camelids (Lama glama, Lama guanicoe, Lama pacos) and llama-guanaco hybrids were sampled for bacterial and mycoplasmal flora. Mycoplasmas were not isolated from any animal. Eleven genera of bacteria were isolated. The most frequent isolates were Staphylococcus epidermidis and Pseudomonas spp. Nine varieties of Pseudomonas were found, which represented at least 3 Pseudomonas species. Many of the bacterial isolates (especially the pseudomonads) are potential pathogens in the eyes of these camelids.     

出壳雏禽卵黄囊阶段营养研究进展

雏禽出壳后的第一周内经历了从内源性营养(卵黄囊)过渡为外源性营养(饲料)的转变.卵黄囊阶段的营养应该是自然选择的结果,特别遇上刮风下雨断食的环境下,是有利于种属持续繁衍的,实属一生中最为特殊和重要的阶段.     

Comparative pathogenesis in specific-pathogen-free chickens of two strains of avian hepatitis E virus recovered from a chicken with Hepatitis–Splenomegaly syndrome and from a clinically healthy chicken

Avian hepatitis E virus (avian HEV) is the primary causative agent of Hepatitis–Splenomegaly (HS) syndrome in chickens. Recently, a genetically unique strain of avian HEV, designated avian HEV-VA, was recovered from healthy chickens in Virginia. The objective of this study was to experimentally compare the pathogenicity of the prototype strain recovered from a chicken with HS syndrome and the avian HEV-VA strain in specific-pathogen-free chickens. An infectious stock of the avian HEV-VA strain was first generated and its infectivity titer determined in chickens. For the comparative pathogenesis study, 54 chickens of 6-week-old were assigned to 3 groups of 18 chickens each. The group 1 chickens were each intravenously inoculated with 5 × 10^2.5 50% chicken infectious dose of the prototype strain. The group 2 received the same dose of the avian HEV-VA strain, and the group 3 served as negative controls. Six chickens from each group were necropsied at 2, 3 and 4 weeks post-inoculation (wpi). Most chickens in both inoculated groups seroconverted by 3 wpi, and the mean anti-avian HEV antibody titers were higher for the prototype strain group than the avian HEV-VA strain group. There was no significant difference in the patterns of viremia and fecal virus shedding. Blood analyte profiles did not differ between treatment groups except for serum creatine phosphokinase levels which were higher for prototype avian HEV group than avian HEV-VA group. The hepatic lesion score was higher for the prototype strain group than the other two groups. The results indicateded that the avian HEV-VA strain is only slightly attenuated compared to the prototype strain, suggesting that the full spectrum of HS syndrome is likely associated with other co-factors.     

Fungal flora of the healthy camelid conjunctival sac.

Swab specimens for fungal isolation were collected from the healthy conjunctival sacs of 3 species of captive camelids (Lama glama, L guanicoe, L pacos) and llama-guanaco hybrids. Fungi were collected from over half the animals in winter (53%) and summer (56%). Fungal species of 10 genera were isolated. In both seasons, Aspergillus was the most commonly isolated genus; at least 9 species of Aspergillus were found. The fungal organisms isolated were similar to those found in healthy eyes of other domestic animals and may represent a random seeding from the environment where they are ubiquitous.