SOME HATCHERY FACTORS INVOLVED IN EARLY CHICK MORTALITY

Observations made in a commerical broiler hatchery revealed that chicks hatched over a period of 48 hours. Chick mortality to 10 days of age was 3.2% for those hatched at the commencement of the hatch, 1.2% for those hatched at peak of hatch and 52.9% for those hatched at the end of hatching. Chicks hatched early were more prone to dehydration while late hatching chicks had a higher incidence of leg weakness. Chicks held for 48 hours in hatcher machines lost 12.5% to 21.7% of their hatching weight and 79.4% of the hatching weight of the yolk sac. Normal 10-day mortality from this hatchery in winter months was observed to be 2.4% but was reduced to 1.2% when staggered setting times of donor flocks was employed by removing chicks from the machines 3 hours after 100% hatch, but was increased to 5.6% by holding chicks in the hatchery in chick boxes for 24 hours at 70 degrees C.     

Effect of Mycoplasma gallinarum on embryonated village chicken eggs

The effect of Mycoplasma gallinarum isolated from village chickens on embryonated village chicken eggs was investigated. Seven-, 10−, 12− and 18-day-old embryos were inoculated with medium containing 10⁶ colony forming units of M gallinarum or with uninfected medium and incubated at 37°C until they hatched. There was no significant difference between the infected embryos which failed to hatch and those which hatched or between them and the group inoculated with medium only. A much higher percentage of the eggs inoculated as 18-day-old embryos hatched than of those inoculated at seven, 10 and 12 days old. The hatchability of the uninoculated village chicken eggs used in the four trials ranged from 60 to 100 per cent. Mycoplasmas were isolated from the oesophagus, trachea and yolk of the infected chicks and from the dead-in-shell embryos.     

Clinical effects, virological and serological responses in chickens following in-ovo inoculation of reticuloendotheliosis virus

Six-day-old embryonated specific pathogen free chicken eggs were inoculated with reticuloendotheliosis virus (REV) into the yolk sac and were incubated until they hatched. The hatchability of eggs inoculated with REV was significantly less (P less than 0.025) than that of media-inoculated controls. Although there were no significant differences in the body weights of these chickens at hatching, there were differences (P less than 0.001) at 6, 25 and 51 days of age between the infected and control chickens. Six of 10 chickens hatched from eggs inoculated with REV had feathering defects at 6 days of age. All chickens hatched from infected eggs had cell-free viraemia and antigenaemia, but not precipitating antibodies. Some of these chickens had very low neutralising antibody titres (less than 45) when examined at 25 and 37 days of age, as did all 10 chickens at 51 days of age. A low rate of horizontal transmission was indicated by the detection of antibodies at 37 and 51 days of age in chickens running in contact with the chickens hatched from eggs inoculated with REV.     

Delayed replication of Marek's disease virus following in ovo inoculation during late stages of embryonal development

Several oncogenic and non-oncogenic isolates of Marek's disease virus (MDV) were inoculated into embryonated eggs on embryonation day (ED) 16 to 18, and embryos or chicks hatching from inoculated eggs were examined for infectious virus and viral internal antigen (VIA) in lymphoid organs. There was no evidence of extensive replication of MDV in any of the embryonic tissues examined. Levels of VIA peaked 4-5 days after chicks hatched. This indicated that MDV remained inactive during embryonation and did not initiate pathogenic events until chicks hatched. Because HVT replicated rapidly in the embryo but MDV did not, in ovo inoculation of HVT simultaneously with oncogenic MDV or several days after MDV resulted in significant protection (P less than 0.025) of hatched chicks against Marek's disease (MD). Little protection was obtained if HVT was given simultaneously with MDV or after MDV to chicks already hatched. The relative susceptibility of the embryo to extensive replication of the vaccine virus but not the challenge virus apparently accounted for protection against MD in chicks hatching from dually infected eggs.     

In ovo injection of branched‐chain amino acids: Embryonic development,hatchability and hatching quality of turkey poults

In this study, the influence of a branched‐chain amino acid blend (BCAA composed of 3 l ‐leucine:1 l ‐valine:2 l ‐isoleucine) injected into the amniotic fluid was evaluated for embryonic growth, yolk‐sac (YS) utilization and development of gastrointestinal tract (GIT) and skeletal muscles of turkey embryos from day 24 of incubation (24E) to hatching, together with hatchability, poult quality and liver L* (lightness), a* (redness) and b* (yellowness) values at hatch. At day 22 of incubation, embryonated eggs (n = 240) were assigned to three treatments, that is, eggs were not injected (control, NC) or injected with 1.5 ml sterile solution with 0.9% salt (SA) or 0.2% BCAA blend (BCAAb). These solutions were injected manually into the amniotic fluid of the embryonated eggs. To determine weights and lengths (where appropriate) of the studied organs and tissues, four embryonated eggs and poults per treatment were selected at 24E and at hatch. While the BCAAb decreased the YS and embryo weight, hatchability and the liver L* value, it increased the weight and quality of poults and the weights of breast and thigh muscles at hatch. In conclusion, the in ovo feeding of the BCAA blend negatively affected hatchability but positively affected hatching weight and poult quality by improving development of skeletal muscles and by regulating energy metabolism.     

Effects of in ovo injection of chrysin,quercetin and ascorbic acid on hatchability,somatic attributes,hepatic oxidative status and early post‐hatch performance of broiler chicks

An experiment was conducted to evaluate the effects of in ovo injection of chrysin, quercetin and ascorbic acid on hatchability, somatic attributes, hepatic antioxidant status and early post‐hatch growth performance of broiler chicks. Four hundred and eighty embryonated broiler breeder eggs containing live 18‐day‐old embryos were divided into six groups of 80 eggs each. One group remained intact and served as a control group (i), whereas the other five groups were injected with the prepared injection solutions as follows: (ii) 0.05 ml distilled water; (iii) 0.05 ml distilled water containing 6 mg ascorbic acid; (iv) 0.05 ml dimethyl sulfoxide (DMSO); (v) 0.05 ml DMSO containing 4.5 mg quercetin; and (vi) 0.05 ml DMSO containing 4.5 mg chrysin. The hatchability rate, hatching weight, residual yolk sac weight, yolk sac‐free body weight, liver weight, hepatic glutathione peroxidase and total superoxide dismutase activities, as well as malondialdehyde concentrations, were not affected by the injected solutions. There were no differences between chicks hatched from the control and in ovo injected eggs in weight gain, feed intake and feed conversion ratio from 0 to 11 days of age. However, the specific contrast performed between the in ovo injected groups and intact eggs revealed that in ovo injection significantly increased hatchability rate (p = .0493). This finding also implies that our injection procedure was harmless. In conclusion, the intra‐egg injection of chrysin, quercetin or ascorbic acid at the injection rates used in this study did not have a significant effect on hatchability, somatic characteristics, early growth performance and hepatic antioxidant status of broiler chicks. However, the overall hatchability was higher in the in ovo injected eggs as compared to non‐injected ones. These findings also confirmed the harmlessness of the procedure developed for in ovo injection in this study.     

Clinical epidemiologic and experimental evidence for the transmission of Newcastle disease virus through eggs

Sporadic outbreaks of Newcastle disease (ND) occurred in Taiwan during 1998-2000. In some cases, the disease occurred in broilers less than 2 wk old that originated in a broiler breeder farm, so spread of the ND virus (NDV) from the infected breeder farm to broiler ranches was suspected. The purpose of the present study was to examine the possibility of the transmission of NDV through eggs. Both clinical and experimental evidence were used to prove that this is possible. From epidemiological investigation, the possibility of transmission through eggs was suggested in two separate ND cases from a breeder farm and its progeny because two identical NDVs were isolated from both cases. In order to clarify the possibility of the transmission through eggs, one mean egg lethal dose (ELD50) of NDV was inoculated into the allantoic cavity of 155 9-to-11-day-old specific-pathogen-free (SPF) chicken embryos. Seventy-one hatching chicks from the inoculated embryos were raised for 14 days. The cloacal swabs from those chicks at the ages of 1, 4, and 7 days and the tissues after necropsy at the ages of 14 days were taken for virus isolation. The same NDV was reisolated from three hatching chicks. This experiment confirms that a few chicken embryos infected in ovo with a low titer of NDV can hatch and contain NDV after hatching, which results in NDV spreading through eggs.     

Pathological and immunological study of goose embryos experimentally infected with duck plague virus

A total of 240 embryonated goose eggs obtained from two susceptible flocks were used. Half of the eggs were inoculated into the allantoic cavity with a virulent strain (7593) of duck plague virus isolated from an acute outbreak, and the other half were inoculated with the attenuated vaccine virus (KAPEVAC). Ten, 100 or 1000 CPU/0.1 ml virus were given on days 12 and 20 of incubation. Embryos that died and surviving embryos killed at 5-day intervals were examined by light and electron microscopy. The yolk and the serum of embryos that survived until hatching were assayed for antibody content. Lymphocytes separated from the blood were used for the immuno-rosette formation and lymphocyte stimulation tests. Pathomorphological changes indicative of virus replication occurred in the liver, kidney, myocardium, gizzard muscle and chorioallantoic membrane (CAM) of the embryos in the case of both virus strains. The time of onset and severity of these changes and the time and rate of embryonic mortality depended on the virulence of the strain used for inoculation, the virus dose and the time of inoculation. Virus-neutralizing (VN) antibodies were demonstrable neither in the yolk nor in the serum of goslings exsanguinated after hatching. The lymphocytes recognized the virus antigen in the in vitro cellular tests and responded to it with blastogenic transformation. As opposed to adult birds, in the embryos duck plague virus infection did not cause damage to the digestive tract mucosa and the lymphoid organs.     

Pathological and immunological study of goose embryos and goslings inoculated with an attenuated strain of Derzsy's disease virus.

An attenuated Derzsy's disease virus strain, designated BAV, was studied in goose embryos. A total of 248 embryonated goose eggs, coming from a susceptible laying flock with no yolk-derived immunity (group I) and from a vaccinated laying flock (group II) were used. The eggs were inoculated into the allantoic cavity with 10(1.9), 10(2.9) or 10(3.9) EID 50/0.2 ml virus on day 12 or day 20 of incubation. Embryos were killed at 5-day intervals. The dead embryos and the hatched goslings (up to 2 weeks of age) were examined by gross and histopathological methods. Reisolation of the virus from the organs was attempted, serum samples were tested for the presence of antibodies, and lymphocytes separated from the circulating blood were used in the lymphocyte stimulation and immunorosette formation tests. Embryos of both groups I and II, inoculated at either time of incubation, showed a body mass gain inferior to that of the controls. Sixteen (group I) and 12 (group II) of the embryos inoculated on day 12 of incubation died. Some (group I: 15, group II: 6) of the embryos inoculated on day 20 of incubation failed to hatch. The pathomorphological changes seen in the embryos killed between days 17 and 22 of incubation were of degenerative character. In embryos killed later (between days 23 and 58 of incubation) the degenerative changes were accompanied by infiltration by inflammatory cells. Reisolation of the virus strain was mostly successful between postinoculation (PI) days 5 and 10. Specific virus-neutralizing antibodies and cellular immune response were demonstrable already at hatching.(ABSTRACT TRUNCATED AT 250 WORDS)     

Non-ventilation during early incubation in combination with dexamethasone administration during late incubation: 1. Effects on physiological hormone levels, incubation duration and hatching events

This study investigated the effect of non-ventilation of the incubator during the first 10 days of incubation and its combination with dexamethasone administration at day 16 or 18 of incubation on hatching parameters and embryo and post-hatch chick juvenile physiology. A total of 2400 hatching eggs produced by Cobb broiler breeders were used for the study. Blood samples were collected at day 18 of incubation, at internal pipping stage (IP), at the end of hatch (day-old chick) and at 7-day-post-hatch for T(3), T(4) and corticosterone levels determination. From 448 to 506 h of incubation, the eggs were checked individually in the hatcher every 2h for pipping and hatching. The results indicate that non-ventilation during the first 10-day shortened incubation duration up to IP, external pipping (EP) and hatch, had no effect on hatchability and led to higher T(3) levels at IP but lower corticosterone levels at 7-day-post-hatch. The injection of dexamethasone at days 16 and 18 of incubation affected hatching and blood parameters in both the ventilated and non-ventilated embryos differentially and the effect was dependent on the age of the embryo. Dexamethasone increased T(3) levels and T(3)/T(4) ratios but the effect was greater with early non-ventilation of eggs. Dexamethasone decreased hatchability but the effect was greater when injected at day 16 and especially in ventilated embryos. The effects of incubation protocols and dexamethasone treatments during incubation were still apparent in the hatched chicks until 7 days of age. The changes in T(3), T(4) and corticosterone levels observed in response to the early incubation conditions and late dexamethasone treatments in this study suggest that incubator ventilation or non-ventilation may influence the hypothalamic-pituitary-adrenal axis (HPA) regulation of stress levels (in terms of plasma corticosterone levels) and thyroid function in the embryo with impact on incubation duration, hatching events and early post-hatch life of the chick. Our results also suggest that some stages of development are more sensitive to dexamethasone administration as effects can be influenced by early incubation protocols.     

Embryo vaccination with infectious bursal disease virus alone or in combination with Marek's disease vaccine

Studies with specific-pathogen-free chickens revealed that chicks hatching from eggs inoculated at the 18th day of embryonation with infectious bursal disease (IBD) vaccine viruses of low virulence (isolates TC-IBDV and BVM-IBDV) developed antibody against IBD virus (IBDV) and resisted challenge with virulent IBDV at 3 weeks of age or older. Embryo vaccination did not adversely affect hatchability of chicks or survival of hatched chicks. Chicks embryonally vaccinated with TC-IBDV had transient histologic lesions in the bursa of Fabricius at hatch. Similar but milder lesions were also noted in chickens that received TC-IBDV at hatch. The level of protection following embryo vaccination with TC-IBDV and BVM-IBDV was similar to that following vaccination with the same vaccines at hatch. Vaccine viruses of moderate virulence (isolates BV-IBDV and 2512-IBDV) were not suitable as vaccines in embryos lacking maternal antibody to IBDV, because the vaccinated chicks developed acute IBD after hatch. Isolate 2512-IBDV was not pathogenic for embryos bearing maternal antibody to IBDV. Maternal antibody against IBDV interfered with efficacy of embryo vaccination with BVM-IBDV but not with 2512-IBDV. Embryo vaccination with a mixture of vaccines against IBD and Marek's disease resulted in protection of hatched chicks against challenge with virulent IBDV and Marek's disease virus.     

Relationships of incubational hatching egg characteristics to posthatch body weight and processing yield in Ross × Ross 708 broilers ,

The characteristics of broiler hatching eggs have the potential to effect broiler posthatch growth and processing yield. The association of set egg weight (SEW), length of incubation (LI), and mean daily percentage of incubational weight loss (MDPEWL) of embryonated Ross × Ross 708 broiler hatching eggs with subsequent posthatch BW and processing yield was investigated. Sixty Ross × Ross 708 broiler hatching eggs were randomly set on each of 8 replicate tray levels of an incubator. Weight loss of individual embryonated eggs between 0 and 10.5, 10.5 and 18.5, and 0 and 18.5 d of incubation was determined for the calculation of MDPEWL. Furthermore, on 18.5 d of incubation, embryonated eggs were transferred to a hatcher unit where they were individually monitored for hatch every 12 h for determination of LI. Chicks were placed in corresponding replicate floor pens and were grown out from 0 (21.5 d of incubation) to 49 d posthatch. Live bird BW as a percentage of SEW on 21.0 d of incubation and d 0 and 49 posthatch, and bird sex on d 49 posthatch were determined. After commercial processing, carcass weight as a percentage of SEW, and carcass, abdominal fat pad, wings, breast muscle, tenders, drumsticks, and thighs weights as percentages of live BW were determined. Bird BW on 21.0 d of incubation and on d 0 and 49 posthatch were positively correlated or interrelated with SEW. Between 0 and 10.5 d of incubation, MDPEWL was negatively correlated with absolute and relative BW on 21.0 d of incubation, absolute BW on d 0 posthatch, and relative tenders weight. Further, LI was positively correlated with absolute and relative BW on 21.0 d of incubation and d 0 posthatch, but was negatively correlated with relative (percentage of live BW) carcass weight on d 49 posthatch. The MDPEWL of modern strain broiler hatching eggs should be closely monitored, particularly during the first half of incubation, for the regulation of LI and hatchling BW and for their potential effects on processing yield characteristics.     

Fetotoxicity of some anticoccidial drugs in chickens

Fetotoxic effects induced by three anticoccidial drugs: robenidine, salinomycin and arprinocid were elucidated in the chicken. Different doses of these drugs were inoculated in groups of embryonated chicken eggs by the yolk sac route. After inoculation, candling of the eggs was performed daily and embryonic or fetal mortalities were recorded. At 19 days old, alive fetuses were collected, weighed, measured and examined morphologically for abnormalities. A group of eggs was kept non-inoculated as a control and another was inoculated with the solvent of the tested drugs. Inoculation of 0.09-9.75 mg robenidine/egg, 0.06-6.75 mg salinomycin/egg or 0.08-8.25 mg arprinocid/egg into the yolk sac of 7 days old embryos caused a dose-dependent fetal death. Arprinocid was the most lethal to chicken fetuses, followed by salinomycin while robenidine was the least. Dead fetuses were usually haemorrhagic, dwarfish and friable. Surviving fetuses showed a dose-dependent reduction in body weight and length, insignificant decrease in leg and wing lengths as well as some developmental abnormalities.     

Comparison of two formaldehyde administration methods of in ovo-injected eggs

Formaldehyde administration in the hatchery can be very useful in decreasing microbial numbers. However, its use is controversial because of the adverse effects that can occur to chicks and people. This study was designed to look at alternative methods of application of formaldehyde in the hatchery. In addition, the study compared the effects of these methods of application on in ovo-and non-in ovo-injected eggs. All in ovo-injected eggs were given diluent only with no vaccine or antibiotic added. In hatchers containing both in ovo-injected eggs and non-in ovo-injected eggs, formaldehyde was administered two ways, dose (DOSE) and constant rate infusion (CRI). In the DOSE hatcher, 12 ml of formaldehyde was administered at one time every 12 hr, whereas in the CRI hatcher, the same volume was administered at a rate of 1 ml/hr over a 12-hr period. A control (CONT) hatcher received 12 ml of distilled water at the same time that the DOSE hatcher was given formaldehyde. In the DOSE hatcher, a peak concentration of formaldehyde of 102 ppm was reached. The CRI was maintained at approximately 20 ppm of formaldehyde. At pipping, the aerosol bacterial load in the hatchers receiving formaldehyde (DOSE, 130 colony-forming units [CFU]/m3; CRI, 82.5 CFU/m3) was significantly less than in the CONT hatcher (235 CFU/m3). At hatch, the CRI (337.5 CFU/m3) was not able to control bacterial levels and only the DOSE hatcher (150 CFU/m3) had a significantly lower aerosol bacterial count. The CRI non-in ovo-injected eggs (93.39%) had a significantly higher percentage of hatch of fertile compared with non-in ovo-injected eggs exposed to water (84.27%). In ovo-injected eggs in CONT and DOSE treatment groups contained significantly higher percentages of visual contamination than non-in on-injected eggs in the same hatchers. This difference had numerical significance only in the treatment groups within the CRI hatcher. The chicks were then placed into replicate treatment groups and grown for 14 days. Chicks from the CRI in ovo-injected eggs had a statistically significant improvement in feed conversion ratio (1.24) at 14 days when compared with chicks from CONT non-in ovo-injected eggs (1.29). All formaldehyde-exposed chicks had numerically lower feed conversion ratios compared with the CONT exposed chicks.     

Role of route of exposure, age, sex, and type of chicken on the pathogenicity of avian reovirus strain 81-176

Chickens were evaluated by age, sex, and type for susceptibility to reovirus strain 81-176 inoculated subcutaneously. Chicks were most susceptible to the lethal effects of reovirus infection at hatching, after which resistance increased rapidly. By 1 week of age, mortality was negligible, but chicks were still susceptible to the less lethal effects of the virus. Mortality rates of males and females were equal. Leghorn and broiler-type chicks did not differ appreciably in their response to viral inoculation. An effort was made to find a more "natural" means of exposure to reovirus than parenteral inoculation. Neither oral nor aerosol exposure was as effective as subcutaneous inoculation. Attempts to transmit reovirus to susceptible hatching chicks, starting when they were in ovo (19 days of incubation), also failed. Decreased weight gain proved to be a valid criterion for judging reovirus infection. Reovirus infection lowered the mean values of body weights, and the standard deviations were substantially greater, indicating an unevenness in size of the affected chickens.     

Effects of in ovo feeding with glycerol for broilers

The objective was to evaluate the effect of in ovo feeding with glycerol on post‐hatch development in broiler chicks. A total of 408 fertile eggs were divided into six experimental groups consisting of five 0.9% saline solutions containing various concentrations of glycerol (12.5, 25.0, 37.5 and 50.0 nmol/ml), and a placebo group (inoculation with saline only) and a control group (without inoculation). Inoculations were performed at 17 days of incubation for the evaluation of hatchability, embryo mortality, body and viscera weights, intestinal epithelium morphometry, blood glucose and liver glycerol kinase activity of chicks at hatching. Inoculation of solutions containing glycerol did not influence body weight at hatching and relative weights of liver, pancreas, intestine and breast. There was a quadratic effect of glycerol levels on the weights of yolk residue and gizzard and on blood glucose, and an increasing linear effect on spleen and heart weights. Higher duodenum and ileum villous height and deeper jejunum and ileum crypts were obtained with 50.0 nmol/ml of glycerol. A linear increasing effect was also observed in liver glycerol kinase activity; however, lower blood glucose was observed with 37.5 and 50 nmol/ml of glycerol. It is therefore concluded that glycerol may be used at doses of 25 nmol/ml as a substrate in in ovo feeding of broiler chickens. However, further studies must be conducted not only to establish an optimal dose but also to evaluate the combination of this substrate with other nutrients used in the in ovo feeding.     

Development in culture of the chick embryo from cleavage to hatch

1. Early uterine embryos were obtained from hens by induced oviposition 7.5-8.0 h after the preceding egg was laid. They were cultured in vitro and then in recipient shells to hatch. As controls, embryos from freshly laid eggs were cultured in recipient shells to hatch. 2. For embryos cultured from uterine eggs, the hatch rate was 22.5%, and for embryos cultured from laid eggs, the hatch rate was 62.5%. 3. The weight of the chicks hatched from culture was about 60% of the weight of the preceding egg, or donor egg. Male and female chicks reached maturity and have produced viable offsprings. 4. The results show that it is possible to grow chick embryos in culture from the early cleavage stage (stage II) to hatch. They extend earlier findings on the culture of embryos from the blastoderm stage (Stage X) to hatch. The technique provides a basis for investigations on chick embryo cryopreservation.     

Hormone-mediated maternal stress affects embryonic development during incubation without adverse effect on chick weight and body composition

1. The objective of this study was to evaluate the effect of maternal stress (MS) induced by supplementing the hen’s diet with 2 mg/hen/d dietary corticosterone (CORT) on embryonic development, biochemical blood parameters and hatching performance of broiler chicks.

2. A total of 200 Ross broiler breeder hens at 42 weeks of age were randomly divided into two groups: MS or control. Hens in the MS were fed 2 mg/hen/d CORT for 14 d. Eggs (648 and 635 eggs for MS and control, respectively) were collected from d 3 to 14 of dietary CORT supplementation and incubated. Weights of embryo, chicks and organs and body composition were determined during incubation and at hatch. Biochemical blood parameters were measured at internal pipping stage and day of hatch. Hatching performance and embryonic mortalities were recorded.

3. Hens fed a diet supplemented with CORT had lighter body weight and produced less eggs at the end of the 14-d treatment period. Although MS embryos were heavier than control from 12 to 18 d of incubation, chick weight was similar at the day of hatch. Lower relative weights for yolk sac and bursa were observed at 12 d of incubation for MS chicks compared to control. Chicks from both groups had similar body content in spite of higher fat content of MS embryos on d 18 of incubation.

4. MS had no effect on the duration of incubation or hatching performance but increased mortality at the pipping stage.

5. The results suggest that hormone-mediated MS might affect embryonic development during incubation without adverse effect on chick weight and body composition.     

Differences in the induction of urate deposition of specific-pathogen-free chicks inoculated with avian nephritis virus passaged by five different methods.

The G-4260 strain of avian nephritis virus (ANV) was passaged using five different methods as follows: method 1, passage three times in chorioallantoic membrane (CAM) of 11-day-old embryonated eggs (CAM3); method 2, passage twice in CAM and further passage once in yolk sac (YS) of 6-day-old embryonated eggs (CAM2-YS1); method 3, passage 11 times in CAM (CAM11); method 4, passage 10 times in CAM and further passage twice in YS (CAM10-YS2); method 5, passage as in Method 4 and then passage three times in chicken kidney cell culture (CAM10-YS2-CK3). CAM11 and CAM10-YS2 were each inoculated orally into 25 one-day-old specific-pathogen-free (SPF) chicks. Seven chicks in the CAM11-inoculated group and six chicks in the CAM10-YS2-inoculated group died or were killed because they were moribund; all had either nephrosis or urate deposition. CAM3, CAM2-YS1, CAM10-YS2, and CAM10-YS2-CK3 were each inoculated intraperitoneally into 15 one-day-old SPF chicks. No chicks inoculated with CAM3 or CAM2-YS1 died, but wo chicks inoculated with CAM10-YS2 and three inoculated with CAM10-YS2-CK3 died with urate deposition. At 14 postinoculation, plasma urate values of the CAM10-YS2- and CAM10-YS2-CK3-inoculated chicks were significantly higher than those of CAM3- and CAM2-YS1-inoculated chicks and control chicks (P less than 0.01). However, interstitial nephritis was observed in most of the ANV-inoculated birds.     

Antiviral activity of crude extracts from Commiphora swynnertonii against Newcastle disease virus in ovo

Studies were carried out to investigate the effect of crude extracts from resin, leaves, stem barks and root barks of Commiphora swynnertonii against Newcastle disease virus (NDV) using an in ovo assay. Nine-day-old embryonated chicken eggs were divided into seven groups (n?=?6) and received various treatments. Six groups were inoculated with velogenic NDV strain; five groups out of these were treated with different concentrations of the four extracts or a diluent, dimethylsulphoxide. The uninoculated and inoculated groups were left as negative and positive controls, respectively. Embryo survival was observed daily and embryo weights were measured day?5 post-inoculation; a few eggs from selected groups were left to hatch. Allantoic fluid from treated eggs and serum from hatched chicks were collected for hemagglutination and hemagglutination inhibition (HI) tests to detect NDV in the eggs and antibodies against NDV in the hatched chicks respectively. Results showed that embryo survival and mean embryo weight were significantly higher (p?<?0.001) in those groups which were treated with the crude extracts from C. swynnertonii than the positive control group. Also the extracts significantly (p?<?0.001) reduced virus titres, whereas no viruses were detected in the allantoic fluids of the resin-treated group at the highest concentration of 500???g/mL. Furthermore, the HI test results showed very low levels of antibodies against NDV in chicks hatched from resin and root bark extract-treated eggs suggesting that these plant materials were capable of destroying the NDV before stimulating the developing chick??s immunity. The current findings have clearly demonstrated that crude extracts especially that of resin from C. swynnertonii have strong antiviral activity against NDV in ovo. In vivo trials are needed to validate the use of resin from the tree in controlling Newcastle disease in chickens.