首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 750 毫秒
1.
SUMMARY Experiments were conducted with vaccines containing the V4 strain of Newcastle disease virus (NDV). Both living aqueous vaccines and vaccines consisting of virus incorporated in an oil emulsion were used. The calculated dose of virus contained in the oil emulsion vaccine was 108,7 50% embryo infectious doses (EID50) per bird dose. Haemagglutinin inhibition (HI) antibody levels of 8 are presumed protective. One-day-old chicks with low levels of maternal antibody were vaccinated intraocularly with 106,3EID50 of live vaccine, and concurrently with oil emulsion vaccine. Presumed protective levels of antibody were present at two weeks post vaccination and were maintained for at least seven weeks longer. When adult birds 15 weeks old with no previous exposure to NDV were vaccinated intraocularly with 106,7EID50 per bird, protective levels of antibody were produced within a week. Unvaccinated birds put in contact with the vaccinated birds produced similar antibody levels within 14 days. Revaccination with oil emulsion vaccine after antibody levels had fallen resulted in a rapid response with high levels of antibody. When antibody-free adult commercial birds with an unknown history of exposure to NDV were vaccinated intramuscularly with oil emulsion vaccine, high antibody levels were produced for at least 21 weeks. Concurrent intraocular inoculation with 107,0EID50 live virus did not enhance the response. Natural infection of unvaccinated birds occurred during the experiment. This was detected by the presence of HI antibody levels of short duration. When antibody-free commercial birds were inoculated intramuscularly with oil emulsion vaccine containing 106,0, 107,0, or 108,0EID50 per bird dose, 100% of birds inoculated with the highest dose produced presumed protective levels of antibody within two weeks, as compared with a 5-week delay when using the 107,0EID50 per bird dose.  相似文献   

2.
Several investigations have recently assessed the ability of some aquatic invertebrates to act as tools for avian influenza A virus (IAV) surveillance as well as their potential role(s) in IAV ecology. Because of this, as well as the high IAV seroprevalence rates noted in select mesocarnivores that commonly inhabit aquatic and semi‐aquatic habitats, we evaluated the effects that freshwater crayfish have on IAV in water at three dose levels and monitored for the presence of IAV in crayfish tissues (gill and green gland) and haemolymph at multiple time points. At relatively high, medium and low (approximately 104, 103 and 102 EID50/ml, respectively) doses, mesocosms containing crayfish (Orconectes sp.) had less detectable IAV RNA present when final water samples were assayed (9 days post‐contact [DPC]). In general, containers without crayfish present had nearly three‐fold greater quantities of viral RNA at 9 DPC. A varying number of RNA positive samples were detected for the three crayfish sample types collected. Gill tissue produced the largest number of positive non‐water samples (n = 26), with the highest quantities detected from crayfish sampled on 1 and 4 DPC (103.5 EID50 equivalent/ml). On a few occasions, gill (n = 8) and haemolymph samples (n = 1) produced higher quantities of viral RNA than their respective water samples or water samples collected 1–2 DPC earlier, but these differences were typically minor. Based upon water samples, statistical models indicated that the interaction of dose and crayfish exposure days explained most of the variation in these data. Future efforts should address if crayfish exposed to IAV‐laden water have the capacity to successfully transmit IAVs to mammals and birds which frequently prey upon them.  相似文献   

3.
This study was conducted to investigate the effect of dietary supplementation of silymarin on performance, jejunal morphology and ileal bacterial population in broiler chicks intoxicated with a mix of aflatoxins. A total of three hundred thirty six 7‐day‐old Ross broiler chicks were randomly distributed between seven experimental groups with four replicates of 12 birds each. Experimental treatments consisted of a control group (unchallenged), and a 2 × 3 factorial arrangement, including two aflatoxin levels (0.5 and 2 ppm) and three levels of silymarin (0, 500 and 1000 ppm). Birds were challenged with a mix of aflatoxins from 7 to 28 days of age. Results showed that increasing aflatoxin level resulted in decreased average daily feed intake (ADFI) and weight gain (ADWG), consequently impaired feed conversion ratio (FCR) throughout the trial period. Dietary supplementation of silymarin resulted in the marked increases in ADFI and ADWG, and improved FCR values in aflatoxin‐challenged chicks. Ileal bacterial populations at days 28 and 42 of age were increased by incremental levels of aflatoxins. On the other hand, dietary silymarin supplementation suppressed ileal populations of Escherichia coli, Salmonella, Klebsiella and total negative bacteria in aflatoxicated birds. Increase in dietary aflatoxin level resulted in the decreased villi height, villi height‐to‐crypt depth ratio (VH:CD), villi surface area and apparent villi absorptive area, while it increased crypt depth, goblet cell count and lymphoid follicular diameter. Feeding silymarin at the level of 1000 ppm increased villi height and VH:CD in aflatoxicated birds. Present results indicate that dietary inclusion of silymarin could improve performance by suppressing ileal bacteria and enhancing absorptive surface area in aflatoxin‐challenged broiler chicks.  相似文献   

4.
H9N2 Avian influenza (AI) is an infectious disease which considered to have low pathogenic virulence, but in the case of coinfection with other pathogens it has the potential to become a major threat to the poultry industry. Infectious bronchitis (IB) and Newcastle diseases (ND) are other common problems to the poultry industry, which there are an extensive vaccination program against these viral pathogens. To investigate the effects of administration of infectious bronchitis and Newcastle disease live vaccines (IBLVs and NDLVs) in the presence of H9N2 AI infection on the immune system and some production parameters, 180 one-day-old broiler chicks were randomly allocated into six groups with different vaccination programs including H120 IBLV, 4/91 IBLV, B1 NDLV and LaSota NDLV. At the age of 20 days, all birds of the experimental groups except the negative control group, were inoculated intra-nasally (at dose of 106 EID50) with H9N2 AIV. After the inoculation, gross and microscopic lesions of the immune organs, serological changes and some production parameters were examined. The findings of this study showed that coinfection of H9N2 AI with NDLVs exacerbated the gross and microscopic injuries in the immune organs; especially the bursa of Fabricius. LaSota + AIV group had the most severe lesion in the bursa of Fabricius, spleen and thymus. Furthermore, the birds of LaSota + AIV group consumed the least amount of feed and water and their final body weight were significantly (P ≤ 0.05) lower in comparison with the other groups. Interestingly, in the context of this experiment both 4/91 and H120 IB live vaccines enhanced the HI antibody titers against H9N2 AIV, but the 4/91 showed the most significant (P ≤ 0.05) increase compared to the other experimental groups.  相似文献   

5.
In this study, we selected three H5N1 highly pathogenic avian influenza viruses (HPAIVs), A/Goose/Guangdong/1/1996 (clades 0), A/Duck/Guangdong/E35/2012 (clade 2.3.2.1) and A/Chicken/Henan/B30/2012 (clade 7.2) isolated from different birds in China, to investigate the pathogenicity and transmission of the viruses in terrestrial birds and waterfowl. To observe the replication and shedding of the H5N1 HPAIVs in birds, the chickens were inoculated intranasally with 106 EID50 of GSGD/1/96, 103 EID50 of DkE35 and CkB30, and the ducks and geese were inoculated intranasally with 106 EID50 of each virus. Meanwhile, the naive contact groups were set up to detect the transmission of the viruses in tested birds. Our results showed that DkE35 was highly pathogenic to chickens and geese, but not fatal to ducks. It could be detected from all the tested organs, oropharyngeal and cloacal swabs, and could transmit to the naive contact birds. GSGD/1/96 could infect chickens, ducks and geese, but only caused death in chickens. It could transmit to the chickens and ducks, but was not transmittable to geese. CkB30 was highly pathogenic to chickens, low pathogenic to ducks and not pathogenic to geese. It could be transmitted to the naive contact chickens, but not to the ducks or geese. Our findings suggested that H5N1 HPAIVs from different birds show different host ranges and tissue tropisms. Therefore, we should enhance serological and virological surveillance of H5N1 HPAIVs, and pay more attention to the pathogenic and antigenic evolution of these viruses.  相似文献   

6.
The present study investigated the effects of Lactobacillus acidophilus (LBA) and mannan-oligosaccharides (MOS) supplementation on the production performance, serum biochemistry, antioxidant profile, health indices, meat quality, and lipid oxidative stability of broiler chicken. A total of 252 commercial broiler chickens at 1 d old of uniform body weight were randomly allocated to 6 maize-soybean-based dietary treatments: T1 (control diet), T2 ( antibiotic bacitracin methylene di-salicylate [BMD] at 20 mg/kg diet), T3 (MOS at 0.1% + LBA at 106 CFU/g feed), T4 (MOS at 0.1% + LBA at 107 CFU/g feed), T5 (MOS at 0.2% + LBA at 106 CFU/g feed), and T6 (MOS at 0.2% + LBA at 107 CFU/g feed). Each treatment was assigned to 6 replicates of 7 birds. The samples for meat quality and serum biochemistry analysis were taken from 12 birds per treatment (2 birds/replicate). The results revealed better (P < 0.01) growth performance and production efficiency of birds fed either T5 or T6 diet compared to control or BMD supplemented diet and BMD-supplemented birds superseded the control birds. Higher (P < 0.01) serum and liver antioxidant enzyme activities, meat antioxidant capacity (2, 2-azinobis-3-ethylbenzothiazoline-6-sulfonic acid [ABTS] and 1, 1-diphenyl-2-picrylhydrazyl [DPPH] assays], serum total protein, high-density lipoproteins (HDL) cholesterol (P < 0.05), and globulin levels (P < 0.01) were observed in birds fed either T5 or T6 diet compared to control or BMD supplemented birds, whereas, lower lipid oxidation (P < 0.01), cardiac risk ratio, atherogenic coefficient, atherogenic index of plasma, serum glucose, triglyceride, total cholesterol levels (P < 0.01), and serum albumin-to-globulin ratio (P < 0.05) were observed in the chickens. The pH of meat from birds fed T4, T5 or T6 diet was lower (P < 0.01) compared to control and other treatments. The extract release volume (ERV), water holding capacity (WHC), and protein content of meat were higher (P < 0.05) in birds fed either T5 or T6 diet compared to control or BMD supplemented birds. Thus, it was concluded that the supplementation of 0.2% MOS along with LBA at 106 CFU/g is optimum for better growth performance, serum biochemistry, antioxidant profile, health indices, meat quality, and lipid oxidative stability of broiler chickens.  相似文献   

7.
A biological assay was carried out to evaluate the impact of dietary tryptophan (TRP) in aflatoxin B1‐contaminated diets (AFB1‐D) on performance, blood parameters, immunity, meat quality and microbial populations of intestine in Japanese quails. Six experimental diets were formulated to include two levels of dietary TRP; 2.9 (moderate high: MH‐TRP) and 4.9 g/kg (excess: Ex‐TRP); and three levels of AFB1 (0.0, 2.5, and 5.0 mg/kg). Each experimental diet was fed to the one of the six groups of birds from 7 to 35 days of age in a completely randomized design with 2 × 3 factorial arrangement. Decrease in feed intake, body weight gain and gain:feed in birds fed 5.0 mg/kg AFB1‐D was restored to the control level by 4.9 g TRP/kg of the diet. The hepatic enzymes in blood were elevated in quails fed on AFB1‐D but attenuated by 4.9 g TRP/kg of the diet (Ex‐TRP; p ≤ .01). High serum uric acid in birds challenged with AFB1 significantly decreased by Ex‐TRP (p ≤ .01). The skin thickness to 2,4‐dinitro‐1‐chlorobenzene challenge suppressed by AFB1 but increased by Ex‐TRP diet (p ≤ .02). The AFB1 increased the malondialdehyde in meat, whereas TRP efficiently diminished malondialdehyde production (p ≤ .01). The greatest drip loss and pH in meat were observed in the birds fed 5.0 mg/kg AFB1‐D but Ex‐TRP augmented the adverse effects of AFB1 (p ≤ .01). The Ex‐TRP reduced the total microbial and Escherichia coli counts (p ≤ .01). The adverse effect of AFB1 on ileal Lactic acid bacteria was completely prevented by Ex‐TRP (p ≤ .03). This study showed that tryptophan supplementation could be considered as a powerful nutritional tool to ameliorate the adverse effects of AFB1 in growing quails.  相似文献   

8.
The undigested nitrogenous fraction entering the hindgut of chickens is further metabolized by microbiota present producing volatile basic metabolites including amines and ammonia (NH3). Ammonia increases pH and may result in overgrowth of Clostridium perfringens further producing toxic metabolites that cause dysbacteriosis or necrotic enteritis (NE). There are few reports in chickens examining the production and concentration of nitrogenous metabolites in the hindgut. A Berthelot reaction using an automated flow, reaction and spectrophotometric instrumentation to detect volatile basic nitrogen in the form of NH3 from cecal contents was carried out. In the Berthelot reaction, NH3 in the sample is chlorinated to monochloramine using dichloroisocyanuric acid that then reacts with salicylate to form 5-aminosalicylate which is stable under alkaline conditions (pH 12 to 13). After oxidation and oxidative coupling, a coloured complex is formed that can be measured at 660 nm. Cecal contents were collected and pooled from 2 birds per pen with 48 pens total in each of 3 experiments and stored in sealed containers at −20 °C prior to analysis. Experiment 1 compared samples collected from birds fed either no meat and bone meal (MBM) or 6% MBM from d 0 to 14, and samples collected from birds fed either no MBM or 5% MBM from d 14 to 42. All birds were challenged with Eimeria on d 9 and C. perfringens on d 14 and 15. Experiment 2 compared cecal contents from birds fed either 0.5% or 0.9% calcium (Ca), and Exp. 3 compared unchallenged with NE challenge on d 16 and 29. Results demonstrated an increase (P < 0.05) in cecal NH3 as a result of feeding MBM or high dietary Ca with a corresponding increase in pH. Birds experimentally challenged with NE had lower cecal NH3 and lower pH on d 16 but not d 29 compared to unchallenged controls. It was concluded that the Berthelot method using Skalar instrumentation equipment is suitable to measure the concentration of volatile nitrogen as NH3 in cecal contents of chickens.  相似文献   

9.
为建立H5N1亚型禽流感病毒感染海兰白鸡模型,本研究选取1株鹅源H5N1高致病性禽流感病毒A/goose/guangdong/1/96(H5N1)(简称GD1/96),测定其对4周龄海兰白鸡的半数致死量.感染模型试验中,将30只4周龄海兰白鸡随机分成3组,每组10只,5只直接感染,5只同居,试验组设置一个重复,将病毒液稀释至104.5EID50,滴鼻、点眼各0.1 mL,对照组接种PBS,感染后24 h放入同居鸡;感染后连续观察14 d,记录死亡时间,每天采集咽喉拭子和泄殖腔拭子;感染组和同居组第3、5 天各剖解3只鸡,采集气管、肺脏、脑、脾脏、肾脏和十二指肠,进行病毒分离;qRT-PCR法分析感染组和同居组第3、5 天鸡肺组织中IFN-α和TNF-α的相对表达量.结果显示,GD1/96株的鸡胚半数感染量(EID50)为10-8.167/0.1 mL,对4周龄海兰白鸡的半数致死量为104.5 EID50.感染模型试验结果显示,以104.5EID50的攻毒剂量感染海兰白鸡,感染组鸡在感染后8 d全部死亡;在感染和同居3 d后,各组鸡的咽喉拭子和泄殖腔拭子均可检测到病毒;感染和同居后第3、5 天,各组鸡的6种组织中均可分离到高滴度的病毒;IFN-α和TNF-α在感染组和同居组的鸡肺脏组织中的表达量均显著增加(P <0.05).本试验建立了海兰白鸡的H5N1亚型禽流感病毒感染模型,为H5N1亚型禽流感病毒的致病机理及表达抗流感基因转基因鸡的研究奠定了基础.  相似文献   

10.
Highly pathogenic avian influenza viruses (HPAIV) of H5N1 subtype are a major global threat to poultry and public health. Export of poultry products, such as chicken and duck meat, is a known source for the cross‐boundary spread of HPAI H5N1 viruses. Humans get infected with HPAI H5N1 viruses either by close contact with infected poultry or through consumption of fresh/undercooked poultry meat. Skeletal muscle is the largest soft tissue in chicken that has been shown to contain virus during systemic HPAIV infection and supports productive virus infection. However, the time between infection of a chicken with H5N1 virus and presence of virus in muscle tissue is not yet known. Further, it is also not clear whether chicken infected with low doses of H5N1 virus that cause non‐fatal subclinical infections continue to accumulate virus in skeletal muscle. We investigated the amount and duration of virus detection in skeletal muscle of chicken experimentally infected with different doses (102, 103 and 104 EID50) of a HPAI H5N1 virus. Influenza viral antigen could be detected as early as 6 hr after infection and live virus was recovered from 48 hr after infection. Notably, chicken infected with lower levels of HPAI H5N1 virus (i.e., 102 EID50) did not die acutely, but continued to accumulate high levels of H5N1 virus in skeletal muscle until 6 days post‐infection. Our data suggest that there is a potential risk of human exposure to H5N1 virus through meat from clinically healthy chicken infected with a low dose of virus. Our results highlight the need to implement rigorous monitoring systems to screen poultry meat from H5N1 endemic countries to limit the global spread of H5N1 viruses.  相似文献   

11.
This study investigated the effects of necrotic enteritis challenge or a necrotic enteritis challenge with an additional challenge from dietary aflatoxin B1 compared to broilers that were unchallenged. Also tested were products designed to help alleviate those effects. Lesion scores were higher in broilers challenged to induce necrotic enteritis, but this did not increase with added aflatoxin. The presence of dietary aflatoxin during a necrotic enteritis challenge significantly increased the negative effects of the necrotic enteritis challenge. During the necrotic enteritis challenge virginiamycin, Calibrin-Z, or a blend of Calibrin-Z, an organic acid, and yucca, helped to decrease the effects of the challenge. When birds are challenged with necrotic enteritis and dietary aflatoxin is present, Calibrin-Z had an advantage over all other tested products.  相似文献   

12.
Probiotics promote the health of the host by maintaining intestinal microbial homeostasis. This study aimed to investigate the benefits of Lactobacillus plantarum BS22 (LP) in the gastrointestinal tract (GIT) microbial homeostasis of broiler chickens exposed to aflatoxin B1 using the PCR‐DGGE, viable count and real‐time PCR. The toxin adsorption experiment demonstrated that treatment R5 (1.0 × 108 CFU/g LP) exhibited good absorptive effect in adsorbing the aflatoxin B1 (AFB1) in vitro. DGGE showed that the composition and structure of gut microbiota were more similar in the mucosa than in the content of all the samples. In addition, higher diversity of the microbiota was observed in the caecum and glandular stomach than in other segments. Lactobacillus, Enterococcus and Enterobacteriaceae were more abundant in the ileum than in the other segments. Enterobacteriaceae in groups I (basal diet) and II (basal diet+50 μg/kg AFB1) showed a significant difference in group III (basal diet + 50 μg/kg AFB1 + 1 × 108 CFU/g LP) in the crop content and duodenum mucosa (p < .05). This investigation indicates that the L. plantarum BS22 promotes GIT microbial homeostasis in broiler chickens exposed to AFB1, particularly for the intestine mucosa microbiota. Thus, L. plantarum BS22 is a possible candidate for degrading AFB1.  相似文献   

13.
The study was conducted to evaluate the effects of different stocking densities on growth performance, antioxidant capacity, and immunity of broilers. One thousand four hundred and forty 22‐day‐old Lingnan Yellow broilers were randomly allotted to five different stocking density groups (8, 10, 12, 14, and 16 birds per m2). Each group consisted of three replicates. The results showed that 8 and 10 birds/m2 groups had higher average daily feed intake (ADFI) than the others (p < 0.05). Heat shock protein 70 (HSP70) in the group of 16 birds/m2 had the highest levels (p < 0.05). The group of 16 birds/m2 had the lowest total antioxidant capability (T‐AOC) and total superoxide dismutase (T‐SOD) activities in blood serum (p < 0.05), and significantly increased interleukin‐1β (IL‐1β) and interleukin‐4 (IL‐4) concentration compared to the groups of 8 and 10 birds/m2 (p < 0.05). In liver, the group of eight birds/m2 had higher T‐AOC levels than that of 12, 14, and 16 birds/m2 (p < 0.05) and also higher catalase (CAT) activities than that of 14 and 16 birds/m2 (p < 0.05); the group of 10 birds/m2 had the highest T‐SOD activities among all groups (p < 0.05). In conclusion, the above results suggest that stocking density of broilers up to 8 or 10 birds/m2 can prevent the negative effects on growth performance and welfare parameters in broilers.  相似文献   

14.
Newcastle disease vaccine CDF-66 has been proved effective by the drinking water route. A chicken dose of 106.2 EID50 in 12 ml of water containing 2.5% skimmed milk was found to be effective. This produced sufficient GMHI antibody response (105) and 86.6% of birds withstood challenge with the Mukteswar strain of virulent virus. The in-contact birds did not show either immune or antibody response. The vaccinated birds excreted vaccine virus only from the respiratory tract not from cloaca. The vaccine given in drinking water protected only 50% of chickens when it was given 168 h prior to challenge virus. With lesser intervals the protection was negligible. Diluted vaccine when held for 2 h at 37°C and room temperature did not show a drop in potency.
Vacunacion Con La Cepa Viral CDF 66 De Newcastle
Resumen La vacuna CDF 66 contra newcastle suministrada en el agua de bebida ha tenido buen resultado. Una dosis individual de 106.2 DIE50 en 12 ml. de agua estabilizada con 2.5% de leche descremada es suficiente para conferir una buena inmunidad. Esta produjo suficientes anticuerpos GMHI (105), y 86.6% de aves resistieron la descarga de virus virulento cepa Mukteswar. Las aves en contacto no mostraron inmunidad ni respuesta de anticuerpos. Las aves vacunadas excretaron virus del tracto respiratorio únicamente. La vacuna en el agua de bebida protegió el 50% de aves cuando se suministró 168 h. antes de la descarga con virus virulento. Con intervalos menores el efecto fue casi nulo. La vacuna diluida no perdió potencia a una temperatura de 37°C por 2 h.
Vaccination Avec La Souche Virale CDF-66 De La Maladie De Newcastle
Résumé Le vaccin contre la maladie de Newcastle à l'aide de la souche CDF-66 dans l'eau de boisson a donné de bons résultats. La dose par animal de 106.2 EID50 dans 12 ml d'eau contenant 2,5 p. 100 de lait écrèmé s'est révélé efficace. Elle a produit une réponse en anticorps GMHI (105) suffisante et 86,6 p. 100 des oiseaux ont résisté à l'épreuve consistant en l'inoculation d'un virus vivant non atténué de la souche Mukteswar. Les oiseaux non traités n'ont montré ni immunité ni réponse antigénique. Les oiseaux vaccinés ont excrété le virus-vaccin par les voies respiratoires seulement et non par le cloaque. Le vaccin administré dans l'eau de boisson a protégé seulement 50 p. 100 des poulets lorsqu'il a été administré 168 heures avant l'epreuve virale. A intervalles moindres, la protection a été négligebale. La dilution vaccinale, lorsque conservée pendant 2 heures à 37°C ou à la température du local, n'a rien perdu de son efficacité.
  相似文献   

15.
The amelioration of aflatoxicosis in Japanese quails was examined by the dietary addition of live yeast (Saccharomyces cerevisiae; SCE). Yeast incorporated into the diet at 1 g kg−1was evaluated for its ability to reduce the deleterious effects of 2·5 mg total aflatoxin ( ; 82·30 per cent 1 , 2·06 per cent 2, 7·68 per cent 1and 7·96 per cent 2) kg−1diet on growing Japanese quail chicks from 10 days to 45 days of age. Forty 10-day-old Japanese quail chicks were assigned to 2×2 factorial arrangement of treatments (control, , , plus ) each consisting of 10 quails. The performances of birds were evaluated. The treatment significantly and dramatically decreased food consumption and body-weight gain from the first week onwards. The significant adverse effect of on the food conversion ratio was also determined from week 1 to the end of the experiments. The addition of to the -containing diet significantly reduced these deleterious effects of on food consumption, body-weight gain and food conversion ratio. Compared to controls, the cumulative body weight gain was reduced by 37 per cent among the quails consuming without , but increased 15 per cent for the birds fed plus . Interestingly, the single inclusion of to the -free diet provided significant improvements in all the investigated growth performances of birds (approximately 40 per cent) compared to controls.  相似文献   

16.
The aim of this study was to investigate the effects of different cage stocking densities on egg production parameters, as well as related stress and immunity indices in Japanese quails under subtropical Egyptian conditions. Two hundred and sixteen birds of Japanese quail at 14th week of age were used in this experiment. The birds were divided randomly into three groups: 60, 72 and 84. Each group subdivided into 4 replicates, where the cages' floor spaces were 200 (S1), 167 (S2) and 143 (S3) cm2/bird, respectively. Birds housed at 200 cm2/bird (S1) had superior fertility (fertility % (p = 0.013) and hatchability % (p = 0.041)), egg production (egg weight (p = 0.034) and egg mass (p = 0.001)) and immunity parameters (higher geometric mean of antibody titres against Newcastle disease virus, p = 0.024). Furthermore, they had higher internal egg quality score: albumen height (p = 0.003), yolk height (p = 0.023), yolk index (p = 0.006) and Haugh unit (p = 0.035). Birds housed at 143 cm2/bird (S3) had the lowest total leucocytic count and lymphocyte % (p = 0.022), but the highest H/L ratio (p = 0.001). Corticosterone concentration was lower in S1 group (p = 0.031) than that in groups housed at higher densities. Japanese quail housed at high densities revealed drop in fertility, hatchability, production and immunity parameters, indicating a detrimental effects on both welfare and economic income.  相似文献   

17.
The current study was planned to develop an efficient vaccine against hydropericardium syndrome virus (HSV). Currently, formalin-inactivated liver organ vaccines failed to protect the Pakistan broiler industry from this destructive disease of economic importance. A field isolate of the pathogenic hydropericardium syndrome virus was adapted to chicken embryos after four blind passages. The chicken embryo-adapted virus was further serially passaged (12 times) to get complete attenuation. Groups of broiler chickens free from maternal antibodies against HSV at the age of 14 days were immunized either with 16th passage attenuated HSV vaccine or commercially formalized liver organ vaccine. The antibody response, measured by enzyme-linked immunosorbent assay was significantly higher (P < 0.05) in the group immunized with the 16th passage attenuated HSV vaccine compared to the group immunized with liver organ vaccine at 7, 14, and 21 days post-immunization. At 24 days of age, the broiler chickens in each group were challenged with 103.83 embryo infectious dose50 of pathogenic HSV and were observed for 7 days post-challenge. Vaccination with the 16th passage attenuated HSV gave 94.73% protection as validated on the basis of clinical signs (5.26%), gross lesions in the liver and heart (5.26%), histopathological lesions in the liver (1.5 ± 0.20), and mortality (5.26%). The birds inoculated with liver organ vaccine showed significantly low (p < 0.05; 55%) protection estimated on the basis of clinical signs (40%), gross lesions in the liver and heart (45%), histopathological lesions in the liver (2.7 ± 0.72), and mortality (35%). Birds in the unvaccinated control group showed high morbidity (84%), mortality (70%), gross (85%), and histopathological lesions (3.79 ± 0.14) with only 10% protection. In conclusion, this newly developed HSV vaccine proved to be immunogenic and has potential for controlling HSV infections in chickens.  相似文献   

18.
  相似文献   

19.
This study aimed to evaluate the effects of dietary supplemental methionine (Met) source and betaine (Bet) replacement for Met on performance and activity of mitochondrial respiratory chain enzymes (MRCEs) in normal and heat‐stressed broiler chickens. Total of 1,200‐day‐old Ross 308 chicks were allocated to two houses, each consisted of 12 treatments, five replicates of 10 birds each with 2 × 2×3 × 2 (temperature × Met source × Met level × Bet, respectively) split‐plot factorial arrangement. Met level in the basal diets was 70% requirements (Req) that was increased to the requirement or 130% by supplemental dl ‐ or l ‐Met. Bet was or was not substituted at the rate of 30% supplemental dl ‐ or l ‐Met. Feed conversion ratio (FCR) in chicks fed 70% l ‐Met was lower than those fed 70% dl ‐Met diet during 1–10 days (p = 0.04). Broilers fed diets containing requirement or 130% Met, regardless of its source, showed higher weight gain (WG) than those received 70% Met diet during 11–42 days (p < 0.001). Feed intake (FI) of broilers fed 130% Met diet was decreased compared to other two groups during 11–42 days (p < 0.05). One hundred thirty percent Met requirement diet resulted in lower FCR comparing to other two groups during 11–42 days (p < 0.001). Heat‐stressed birds grew less than those under normal condition (p < 0.05). Broilers fed Req Met diet under normal temperature exhibited higher activities of complexes (Cox) I and III (p < 0.05). Cox I activity in heat‐stressed birds fed Bet + diet was similar to those fed Bet‐diet under normal temperature (p = 0.046). It is concluded that performance and the activities of Cox I and III were increased as the level of Met increased. Bet replacement for 30% supplemental Met resulted in similar consequences comparing to non‐Bet replacement diets on performance, but increased the activity of Cox III. l ‐Met was effective than dl ‐Met at the cellular level. High ambient temperature depressed performance and MRCE activity.  相似文献   

20.
The formulation and evaluation of trehalose nano-organogels for storage and oral delivery of Newcastle disease (ND) strain I-2 vaccine to chickens were carried out in this study. Trehalose sugar was blended with vegetable oil to form nano-organogels where trehalose also acted as a stabilizer against thermal inactivation of I-2 ND virus. Results from infectivity titration assay indicated that the titre of 107.5 EID50/0.1 mL was maintained after 12 weeks of storage of nano-organogel I-2 vaccine at ambient room temperature. Serology results showed that 33% chickens which were vaccinated with nano-organogel I-2 vaccine after 14 days had HI antibody titres of ≥ 3.0 log2 with GMT of 2.3. Moreover, results showed 100% of chickens vaccinated with nano-organogel I-2 vaccine had the mean antibody titres of 3.4 and 3.7 log2 at 21 and 28 days after vaccination, respectively. All vaccinated chickens (100%) survived the challenge of virulent ND virus whereas all unvaccinated chickens succumbed to challenge and died of signs consistent with ND. The findings from this study showed that the nano-organogel I-2 vaccine was stable at room temperature, safe and produced protective antibody response in vaccinated chickens. Moreover the nano-organogel I-2 vaccine was used for oral administration and hence is suitable for mass vaccination. However, optimization of the formulation of trehalose nano-organogel vaccine is required in order to achieve its application potentials.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号