商品蛋鸡绦虫病的诊治

绦虫病是鸡常见的一种寄生虫病，主要危害雏鸡，能引起雏鸡大批死亡，但引起成年蛋鸡发病的报道却很少。2003年10月，辽西地区，尤其是锦州周边地区的一些蛋鸡饲养户饲养的商品蛋鸡陆续发生绦虫病，造成鸡产蛋量下降及部分鸡死亡。现将发病及诊治情况报告如下。     

The efficacy of three commercial Mycoplasma gallisepticum vaccines in laying hens

The efficacy of three commercial Mycoplasma gallisepticum (MG) immunizing agents-a bacterin, a recombinant fowlpox-MG vaccine, and a live F-strain vaccine-was compared in specific-pathogen-free hens in egg production. Three groups of 25 chickens were vaccinated with one of the vaccines at 10 wk of age and 25 birds were not vaccinated. At 25 wk of age (and approximately 50% egg production), 20 birds from each of the three vaccinated groups and 15 nonvaccinated controls were challenged with virulent R-strain via aerosol; the birds were necropsied and evaluated at 10 days post-challenge. The MG bacterin and live F-strain vaccinations were both protective and resulted in significant differences in air sac lesions, tracheal lesions, and ovarian regression compared to the nonvaccinated controls and the recombinant fowlpox-MG vaccine (P < or = 0.05). The evaluation of ovarian regression is a useful method of testing the efficacy of MG vaccines in laying hens.     

Nesting and floor laying by domestic hens in a commercial flock

1. The nesting behaviour of broiler breeders was studied in a commercial flock of nearly 4000 birds kept on deep litter by tagging a sample of 200 hens. Use of nest boxes by tagged birds was recorded on 52 d over 34 weeks.

2. Forty hens were never observed in nest boxes and 33 others were recorded only in ground‐level boxes. These 73 birds were recorded significantly less often in nest boxes and more often apparently laying on the floor than others. Fewer of them perched during observations and they started doing so later than birds which used raised nest boxes.

3. These results suggested that there were consistent floor layers, which had difficulty reaching raised nest boxes, as found previously in experimental conditions. Many or all floor layers may, however, have used ground‐level boxes sometimes.

4. Hens were inconsistent in their use of particular nest boxes, and some even nested in two distinct areas.

5. Most individuals were, however, consistent in their reaction to one or more features of the nest boxes, including height, aspect and area. Individual choices for these features varied, so no boxes were used particularly heavily, with the exception of those at ground level.     

Characterization of Escherichia coli isolates from peritonitis lesions in commercial laying hens

Five clinically normal chickens from three farms (farm A, farm B, and farm C), for a total of 15 clinically normal chickens, were examined bacteriologically. In a similar manner, five dead chickens with lesions of peritonitis from each of the same three commercial egg-laying operations were selected for bacterial culturing. Escherichia coli were isolated from the cloaca in 14 of 15 healthy chickens and from all 15 chickens with peritonitis. Oviducts of normal chickens did not contain E. coli (0/15) whereas oviducts from 13 of 15 hens with peritonitis were positive for this pathogen. No lesions and no E. coli (0/15) were found in the peritoneal cavity of healthy hens, but peritonitis lesions from 13 of 15 dead chickens yielded E. coli. On farm A and farm B, a flock consisted of all chickens within a single house and all chickens in each flock were of the same age and same genetic strain. In flock 1 from farm A, all five E. coli isolates from the oviduct and all five isolates from the peritoneal cavity were serogrouped as O78; contained the virulence genes iroN, sitA, iutA, tsh, and iss; and belonged to phylogenetic group A. In flock 2 from farm B, all four E. coli isolates from the oviduct and all four isolates from the peritoneal cavity were serogrouped as O111; contained virulence genes iroN, sitA, iutA, traT, iss, and ompT; and belonged to phylogenetic group D. These data suggest that all chickens with peritonitis in a single flock on farms A and B were likely infected by the same E. coli strain. Escherichia coli isolates from the magnum and peritoneum had the same serogroup, virulence genotype, and phylogenetic group, which is consistent with an ascending infection from the oviduct to the peritoneal cavity.     

Effects of commercial enzyme preparations on egg and eggshell quality in laying hens

1. Four different commercial enzyme products were added to standard commercial layer diets, based on barley, wheat or triticale. 2. Diets were fed to 4 different strains of commercial laying hen: ISA Brown, Hy-Line CB, Tegel SB2 and Tegel HiSex. 3. Diets were given for 5 weeks prior to measurements of egg and eggshell quality. 4. The inclusion of commercial enzyme products in the diets had no effect on egg weight. 5. Positive effects of the enzymes were: improved eggshell breaking strength, shell weight, percentage shell and shell thickness for the barley-based diet and increased eggshell breaking strength for two of the enzymes with the wheat-based diets. 6. Negative effects of the enzyme products were slightly lighter coloured eggshells and reduced albumen quality for the barley-based diet and for two enzymes with the wheat-based diet. 7. The addition of commercial enzyme preparations had no main effect on egg and eggshell quality for the triticale-based diet, except for effects on yolk colour. 8. Yolk colour was lower than control for enzyme 3 in all diets and for enzyme 4 with the barley- and wheat-based diets. 9. Further investigation is required to elucidate the specific enzyme components that influence egg quality.     

Decreased egg production in commercial laying hens fed zearalenone- and deoxynivalenol-contaminated grain sorghum

In an experiment to determine the effect of corn vs. grain sorghum on performance of laying hens, egg production decreased significantly in the grain sorghum-fed hens in each of two trials starting 24 weeks after the trials began. Necropsy of chickens fed both diets revealed buccal ulceration at the ventral aspect of the oral cavity and squamous metaplasia of the esophageal glands and submaxillary salivary glands. Lesions were much more severe in the sorghum-fed birds than in the corn-fed birds. Analysis of the grain sorghum and corn revealed the presence of mycotoxins. Zearalenone and deoxynivalenol were present in the grain sorghum, and a lower amount of deoxynivalenol and a trace of aflatoxin B1 were found in the corn. Although mycotoxin levels were low, interaction between these mycotoxins and others may have decreased egg production.     

"家禽肠道疾病及其预防措施"专栏(五) 产蛋母鸡的慢性肠炎

目前处理慢性肠炎的方法,是在不知病因的情况下通过增强母鸡的抵抗力和提高其康复率来控制疾病.这是荷兰两位家禽疾病研究人员的结论.     

Immune response following vaccination against Salmonella Enteritidis using 2 commercial bacterins in laying hens

The humoral and cell-mediated immune (CMI) response to 2 commercial killed Salmonella Enteritidis (SE) vaccines (Layermune and MBL SE4C) was evaluated in laying hens. Layers were distributed in 2 experimental groups. The first received a single immunization at 16 wk of age, while the second experimental group was immunized at 12 wk of age and again at 18 wk of age. Serum immunoglobulin (Ig)G antibodies were measured using a commercial SE ELISA kit and showed persistent levels from 3 to 32 and 34 wk post-vaccination. The vaccination protocol using 2 immunizations showed a higher seroconversion level than the single vaccination. However, our results for bacterial intracellular survival indicated that IgG titers were not linked with bacterial killing. Local IgA production was measured in the intestines and oviducts with an in-house SE whole cell antigen ELISA. Only the MBL SE4C vaccine elicited IgA antibody production when tested on intestine and oviduct mucosal secretions, 3-weeks post-vaccination in both immunization protocol groups. To evaluate the CMI response, the splenic T-cells and B-cells populations were analyzed using flow cytometry. The CD3/B-cell ratio decreased 3 wk after the second immunization in the twice vaccinated Layermune group due to an increase in B-cells.     

蛋鸡产蛋后期的营养调控

蛋鸡产蛋后期精准的营养调控可延缓蛋鸡的衰老,延长产蛋期,提高经济效益.本文从能量、蛋白质、维生素、矿物元素的营养需要等方面对蛋鸡产蛋后期的营养调控进行总结,以期能够对产蛋鸡后期的营养调控提供参考.     

Fear of humans and its relationships with productivity in laying hens at commercial farms.

1. The relationship between the behavioural responses of laying hens to humans and productivity was determined at 16 commercial sheds from 14 farms. 2. A number of behaviour variables were moderately to highly correlated with production variables; for example, the proportion of birds that moved away from an approaching experimenter in an unfamiliar environment ('shute test') was negatively correlated with peak hen day production, (PKHDP). 3. Behavioural responses to humans accounted for between 23 and 63% of the variation in a number of production variables, including PKHDP and the duration of a high level of production. 4. Inclusion of farm factor variables increased the amount of variation accounted for by the behaviour variables. For example, adding the variable 'time/day spent in the shed by stockpeople' to the behaviour variables 'the proportion of birds that moved away from an approaching human' in the shute test and 'the number of times birds in cages adopted an erect posture' in response to an approaching human increased the variation accounted for in PKHDP from 53 to 61%. 5. The results suggest that fear of humans may be a factor that limits the productivity of commercial laying hens.     

Ultrastructural study of infectious bronchitis virus infection in infundibulum and magnum of commercial laying hens

The infundibulum and magnum of the oviduct were examined in hens in full lay which were infected with two Australian strains of infectious bronchitis virus (IBV). The ultramicroscopic changes in the infundibulum and magnum were compared with control hens which had eggs at different positions in the oviduct. The ciliated and granular cells of the surface epithelia and secretory epithelial cells of the tubular glands were the target cells of IBV. No pathological changes were recorded during 2-8 days post-infection (p.i.). Patchy loss of cilia occurred at 10-14 days p.i. Between 16 and 24 days p.i., there was no cilia loss and lymphoid nodules were observed in the muscularis layer of the infundibulum and magnum of some hens from both infected groups. Virus particles were detected mostly in the rough endoplasmic reticulum (RER) and Golgi complex between 10 and 12 days p.i. Cytopathology was noticed in various cell organelles between the 10th and 14th days p.i. There was an increase in RER deposits in infected cells, irrespective of egg position in the oviduct. The magnum was more affected than the infundibulum. Cellular changes were more severe in the infundibulum and magnum of T-infected hens as compared to N1/88-infected hens. Eggs with watery whites which were laid by infected hens could be attributed to cytopathological changes in the granular epithelial cells and tubular gland epithelial cells of the magnum resulting in reduced synthesis of albumen proteins. IBV can cause pathology in parts of the fully functional oviduct which may persist up to the 30th day p.i. However, both the challenge strains of IBV can cause a small number of hens to cease production. Loss of cilia in both the infundibulum and magnum pose a potential threat of secondary bacterial infection and also may affect fertility in breeder hens.     

Perching and floor laying by domestic hens: Experimental results and their commercial application

1. The effect of perching experience on use of ground level nest boxes was tested in medium hybrid hens. Twelve out of 14 hens (86%) reared without perches laid their first egg on the floor when isolated with ground level nests. Only 4 out of 19 hens (21%) reared with perches laid on the floor. Medium hybrids with experience of only one level apparently have difficulty even stepping up to another level.

2. The age at which perches should be introduced to minimise floor laying was investigated in a second experiment with medium hybrids. Five groups had perches provided at 4, 8, 12, 16 and 20 weeks respectively. Floor laying in the first group varied between 0 and 10%. The proportion of floor eggs laid by the other groups was between 31 and 100% initially, falling to between 23 and 43% by the end of the experiment. Provision of perches as early as possible is recommended.

3. In a commercial trial, perches were provided in a rearing pen of 2600 broiler grandparents. A control pen of 2130 birds had no perches during rearing. At 30 weeks old, floor laying in the experimental flock was 5% of total production, compared to 11% in the control flock. The effect of providing perches during rearing on subsequent floor laying may be of considerable commercial significance.