Experimental infection of broiler breeder hens with the intestinal spirochaete Brachyspira ( Serpulina ) pilosicoli causes reduced egg production

The pathogenic potential of the anaerobic intestinal spirochaetes Brachyspira ( Serpulina ) pilosicoli and Brachyspira innocens was evaluated in adult chickens. Thirty 17-week-old Cobb broiler breeder hens were individually caged in three groups of 10 birds. Control birds (group A) were sham inoculated with sterile broth medium. Birds in the other two groups (groups B and C) were inoculated, respectively, with an isolate of B. innocens or of B. pilosicoli . Birds were monitored daily, and killed at 41 weeks of age. Infection had no consistent effect on body weight gain, but inoculation with B. pilosicoli resulted in a transient increase in faecal water content. B. innocens infection had no effect on egg production, but B. pilosicoli infection caused a delayed onset of laying, and a highly significant reduction in egg production over the first 11 weeks of lay. This study confirms that B. pilosicoli can cause serious egg production losses in adult chickens, while B. innocens is not obviously pathogenic.     

A survey of mortality in three adult broiler breeder flocks

A survey was carried out on the causes of mortality in three broiler breeder flocks during the laying period from May 1976 to February 1977. Five hundred and forty-two birds were examined. The commonest causes of death in the females were reproductive disorders (24.9%), cellulitis or injury due to cannibalism (24.0%), kidney lesions (9.5%), liver haemorrhage (7.1%), Marek's disease (4.9%) and staphylococcal synovitis/tenosynovitis (4.1%). Mortality in the males was due mainly to staphylococcal synovitis/ tenosynovitis (33.8%) and acute heart failure (14.3%).     

Antimicrobial resistance and epidemiology of Escherichia coli in broiler breeder chickens

Escherichia coli isolates were obtained from two flocks of broiler breeder chickens beginning at 1 day old. Antimicrobial sensitivities were determined and isolates were grouped on the basis of their antibiogram patterns. In both flocks there was an initial dramatic shift in the antimicrobial resistance patterns of the E. coli isolates which changed from sensitive to multiresistant. Both flocks were given spectinomycin in drinking water during the first 3 days on the rearer farm. Statistical analysis of the E. coli isolates in Flock 2 revealed that there was a significant difference between E. coli obtained from 1-day-old birds and those obtained from 1-week-old birds in terms of the proportion of isolates that were resistant to spectinomycin. It is possible that the use of spectinomycin selected for resistant E. coli isolates which became dominant in the flocks soon after treatment. There was a strong association between resistance to spectinomycin and resistance to other antimicrobial agents, in particular, suiphafurazole and chloramphenicol.     

The toxic effects of monensin and chloramphenicol on laying turkey breeder hens.

A case report of choramphenicol and monensin poisoning in turkey breeder hens is presented in which anorexia and a fall in egg production were features. An experiment study was then conducted in turkey breeding hens given increasing levels of monensin and chloramphenicol singly or in combination. Monensin fed at levels of 42 or 85 ppm had no adverse effect on egg production but chloramphenicol in the drinking water at 500 mg/l for 4 days caused a 9.2% fall in egg production compared to control untreated birds. When 500 mg/l chloramphenicol and 42 ppm monensin were given together for 8 days there was lameness, 12% mortality, but no drop in egg production. When 70 ppm monensin and 500 mg/l chloramphenicol were given together for 4 days, 14 of 22 birds died and egg production in the remainder ceased. Withdrawal of monensin arrested mortality but egg production did not recover. Serum creatine phosphokinase levels in this group were 20 times greater than those of the controls and were similar to birds studied in the case report.     

Concentrations of plasma potassium and sodium during the life of a broiler breeder flock

Plasma samples were taken from a normal broiler breeder flock during the period 10 to 60 weeks of age. Plasma potassium concentration was variable during maturation, reaching the lowest value at 26 weeks of age. Plasma sodium concentration also declined but with the lowest value at 20 weeks of age.     

Avian hepatitis E virus infection and possible associated clinical disease in broiler breeder flocks in Hungary

In broiler breeder flocks in one broiler integration in Hungary, a new syndrome appeared in January 2005 with initially four successive post-peak flocks experiencing significant decreases in egg production. Clinically birds became depressed and there was a small increase in the mortality rate. Postmortem examinations revealed enlarged livers in up to 19% of birds dying, and enlarged spleens in some. Also observed were birds with either clotted blood or serosanguineous fluid in the abdomen and subcapsular haemorrhages of the liver. Histopathology and polymerase chain reaction excluded tumours and the presence of common tumour-associated viruses. Chronic bacterial infections (especially causing hepatitis, peritonitis and airsacculitis) were common but many enlarged livers had no obvious bacterial involvement. After a 9-month period during which a majority of flocks became affected, no newly affected flocks occurred. Investigations showed that all tested affected flocks were seropositive in the big liver and spleen (BLS) Agar Gel Immunodiffusion test. Subsequent flocks without post-peak egg-production drops were shown to be seronegative in the BLS AGID test, as were all the parent flocks contributing to the affected flocks. Liver samples and cloacal swabs were positive by polymerase chain reaction (aHEV helicase target), and calicivirus-like particles were demonstrated in bile samples from affected birds. These observations are similar to hepatitis-splenomegaly syndrome as described in North America and BLS syndrome as described in Australia. Histopathological features were a non-specific chronic hepatitis similar to those described in BLS and hepatitis-splenomegaly syndrome. Immunohistochemistry using a BLS-specific monoclonal antibody confirmed the presence of avian hepatitis E virus antigen in livers and spleen.     

Induction of sperm abnormalities in mice by quercetin

Sperm abnormalities in mice induced by IP injection of quercetin at total cumulative doses of 16, 32, 80, and 160 mg/kg b. wt. administered fractionally on 5 successive days were quantitated by assessing the percent of sperm with abnormal heads or tails. Five weeks after the final injection a maximum of 14.8% abnormal sperm were observed with a total quercetin dose of 80 mg/kg b. wt. compared to the spontaneous control of 0.98%. Concomittantly, a 32.1% reduction in testicular weight occurred compared to control mice which was coincident with a reduction in sperm count of 28%.     

Variations of clinical biochemical parameters of laying hens and broiler chickens fed aflatoxin-containing feed

Two groups of 32 laying hens (Hyssex Brown) and two groups of 32 23-day-old (Hybro) broiler chickens were fed 2.5 and 5 parts/10(6) of aflatoxin in their diet for 4, 8, 16 and 32 days; 16 hens and 32 chicks were maintained as control groups (0 parts/10(6)). After the intoxication period, a clearance period was established of 1, 2, 4 and 8 days. Relative weights of liver and kidneys significantly increased in intoxicated hens, but not in broiler chickens. Histological lesions in both types of bird consisted of hepatic cell vacuolation with fatty infiltration. There was a significant decrease (P< 0.001) in egg production in the 5 parts/10(6) group, which started to recover during the clearance period. No morbidity or mortality due to the aflatoxicosis were observed in either type of bird. In intoxicated laying hens, cholesterol levels were not significantly (P> 0.05) different from control values, but triglyceride levels decreased (P< 0.001) in both intoxicated groups. The effect of aflatoxin on calcium and phosphorus levels was important, because on the 4th day their values decreased significantly. Aspartate aminotransferase (AST) serum levels remained normal, whereas alanino aminotransferase (ALT) activity decreased in both intoxicated groups. The activity of serum lactic dehydrogenase (LDH) and gammaglutamil transferase (GGT) increased significantly. In intoxicated broiler chickens, aflatoxins did not alter (P> 0.05) the biochemical parameters studied, except that the serum calcium concentration was lower in the 5 parts/10(6) group. These data indicated that in intoxicated laving hens, a severe clinical biochemical alteration was produced, and that this together with the hepatic lesions observed in hens and broilers may aid disease diagnosis.     

The effect of Ornithobacterium rhinotracheale vaccination of broiler breeder chickens on the performance of their progeny

The effect of Ornithobacterium rhinotracheale vaccination of broiler breeders on antibody titres and performance of breeders and broilers was investigated. O. rhinotracheale antibody titres and performance data were recorded from 16 different broiler breeder flocks and from 79 of their broiler progeny flocks. Eight breeder flocks were vaccinated with an inactivated O. rhinotracheale vaccine while the other eight breeder flocks were left unvaccinated against this bacterium. Following vaccination, mean O. rhinotracheale antibody titres in the breeders rose to a 6.5 log 2 units higher value than in unvaccinated breeders, and remained at a mean titre of 15 log 2 units during the entire production period. This resulted in significantly higher maternal antibody titres against O. rhinotracheale in the broiler progeny of vaccinated breeder flocks compared with the offspring of unvaccinated flocks. Statistical analyses revealed no differences in performance between vaccinated and unvaccinated breeders. There was a significantly lower mean mortality rate and higher mean production index in the broilers derived from vaccinated breeders.     

Immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed

This study aimed to evaluate the immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed. For this purpose, 84 White Leghorn (WL) layer breeder hens (40-weeks-of-age) were divided into seven groups (A–G). Hens in the Group A were fed a commercial layer ration while those in Groups B–G were kept on a diet amended with 0.1, 0.5, 1.0, 3.0, 5.0, or 10.0?mg OTA/kg, respectively, for 3 weeks. Fertile eggs were set for hatching on the weekly basis to get the progeny of each week separately. Hatched chicks (n?=?10 from each group) were euthanized at Day 14 of age, and their immunological organs weighed and fixed in neutral buffered formalin. An indirect immunoperoxidase method was applied to study the frequency of immunoglobulin(s)-bearing cells in the spleen and bursa of Fabricius from these progeny. From other chicks within each set, at Day 16 of age, lymphoblastogenic responses against an intradermal administration of phytohemagglutinin (PHA-P) were determined. Relative weights of the bursa of Fabricius and of the thymus were significantly lower in the progeny of hens fed OTA-contaminated diet for 14 and 21 days. The frequencies of IgA-, IgG-, and IgM-bearing cells were also significantly (P?≤?0.05) lower in the bursa of Fabricius and spleen of the progeny chicks obtained from dams fed the OTA-mixed diet. Progeny chicks obtained from the breeder hens fed higher doses of OTA showed significantly lower responses to PHA-P than did counterpart chicks from control hens. The findings of this study suggested that there were immunosuppressive effects from OTA in the progeny obtained from breeder hens kept on OTA-contaminated diets.     

Immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed

This study aimed to evaluate the immunological status of the progeny of breeder hens kept on ochratoxin A (OTA)-contaminated feed. For this purpose, 84 White Leghorn (WL) layer breeder hens (40-weeks-of-age) were divided into seven groups (A-G). Hens in the Group A were fed a commercial layer ration while those in Groups B-G were kept on a diet amended with 0.1, 0.5, 1.0, 3.0, 5.0, or 10.0?mg OTA/kg, respectively, for 3 weeks. Fertile eggs were set for hatching on the weekly basis to get the progeny of each week separately. Hatched chicks (n?=?10 from each group) were euthanized at Day 14 of age, and their immunological organs weighed and fixed in neutral buffered formalin. An indirect immunoperoxidase method was applied to study the frequency of immunoglobulin(s)-bearing cells in the spleen and bursa of Fabricius from these progeny. From other chicks within each set, at Day 16 of age, lymphoblastogenic responses against an intradermal administration of phytohemagglutinin (PHA-P) were determined. Relative weights of the bursa of Fabricius and of the thymus were significantly lower in the progeny of hens fed OTA-contaminated diet for 14 and 21 days. The frequencies of IgA-, IgG-, and IgM-bearing cells were also significantly (P?≤?0.05) lower in the bursa of Fabricius and spleen of the progeny chicks obtained from dams fed the OTA-mixed diet. Progeny chicks obtained from the breeder hens fed higher doses of OTA showed significantly lower responses to PHA-P than did counterpart chicks from control hens. The findings of this study suggested that there were immunosuppressive effects from OTA in the progeny obtained from breeder hens kept on OTA-contaminated diets.     

Comparative study on the determination of serum thyroid hormones by two methods of immunoassay in broiler breeder poultry

Variations in blood thyroid hormone concentrations give an indirect indication of changes in thyroid gland activity; therefore, selecting a suitable method to determine these hormones is crucial. The aim of this study was to compare serum thyroid hormone concentrations (i.e. T₄, T₃, fT₄ and fT₃) using chemiluminescence immunoassay (CLIA) and enzyme-linked immunosorbent assay (ELISA) methods in broiler breeders. This study was carried out on 30 blood samples from randomly selected 45-week-old broiler breeders. Blood samples were collected in summer from the wing vein of birds by using disposable syringes. The separated serum was analysed to determine thyroxine (T₄), triiodothyronine (T₃), free thyroxine (fT₄) and free triiodothyronine (fT₃) concentrations using the mentioned methods. Data were processed in excel and statistical analysis was carried out using SPSS/ver17 software. Our data from this study indicates there was a significant difference in the T₄ (P < 0.0001), fT₄ (P < 0.01) and fT₃ (P < 0.05) concentrations between the two methods and that the levels of these hormones were higher when using the CLIA method, except for fT₃. The linear regression analysis of these hormones showed that the CLIA and ELISA results were significantly correlated only for fT₄ (P < 0.0001, r = 0.798) concentration. In conclusion, determination of the thyroid hormones using the CLIA method had an acceptable performance of higher sensitivity and precision and was more appropriate than the ELISA method for clinical application and investigation in poultry.     

Serologic prevalence of Ornithobacterium rhinotracheale infections in broilers and broiler breeder chickens in Kermanshah Province,west of Iran

The presence of Ornithobacterium rhinotracheale (ORT) in poultry farms in several parts of Iran has been confirmed over the last few years. The purpose of this study was to determine the presence of ORT antibodies by enzyme-linked immunosorbent assay (ELISA) in broiler and broiler breeder chickens in western parts of Iran. In a one-year period, from April 2009 to February 2010, a total of 435 blood samples were collected from 30 commercial chicken flocks (24 broiler flocks and six broiler breeder flocks) located in Kermanshah Province, west of Iran. None of the broilers and broiler breeders have been vaccinated against ORT prior to sampling. The province was divided into four geographical areas: southwest, southeast, northwest, and northeast. Flocks in each area, specifically the birds in each flock, were randomly sampled. The presence of antibodies against ORT in each serum sample was tested twice by ELISA using a commercial kit. The results revealed that 50.1 % broiler and 70.5 % broiler breeder chickens were serologically positive for ORT. Out of 347 serum samples obtained from broiler chickens, 174 (50.1 %) were positive for ORT antibodies, which represented 18 (75.0 %) of 24 examined broiler flocks. A higher rate of seropositivity (71.4 % of samples and 83.3 % of broiler flocks) was observed in the northwest. Out of 88 samples obtained from broiler breeder chickens, 62 (70.5 %) were positive for ORT antibodies, which belonged to six (100 %) of the examined broiler breeder flocks. Detection of anti-ORT antibodies among broiler breeders was significantly higher than that of broilers.     

An outbreak of lymphomas in commercial broiler breeder chickens vaccinated with a fowlpox vaccine contaminated with reticuloendotheliosis virus

Gross and microscopic examinations of affected tissues from chickens of two commercial broiler breeder flocks aged 27 and 31 weeks revealed lesions of visceral lymphomas with bursal involvement in some chickens. Reticuloendotheliosis virus (REV), but not avian leukosis virus (ALV), was isolated from blood of affected chickens. Furthermore, DNA extracted from tumours tested positive for REV, but not for ALV or Marek's disease virus by polymerase chain reaction (PCR) test. Attempts to determine the source of REV infection included testing a commercial fowlpox (FP) vaccine used to immunize flocks at 7 days of age. Chicken-embryo fibroblasts inoculated with the FP vaccine tested positive for REV by PCR and immunofluorescent tests. REV was also isolated from plasma of pathogen-free chickens experimentally inoculated with FP vaccine at hatch; two of eight (25%) inoculated chickens developed lymphomas by 34 weeks of age. Antigenic characterization of REV isolated from commercial broiler breeder chickens and from FP vaccine, using monoclonal antibodies, revealed that both isolates belong to subtype 3 of REV. The data represent the first report of an outbreak of REV-induced lymphomas in commercial chickens. The data also indicate that the source of REV infection is an REV-contaminated commercial FP vaccine.     

Induction of maternal behavior in incubating and non-incubating hens: influence of hormones

Maternal responses and variations in plasma levels of prolactin and testosterone have been studied in incubating and in non-incubating, non-laying hens during forced adoption experiments. The results demonstrate the ability of incubating hens to display complete maternal behavior as early as the 10th day of incubation after being exposed to stimulation by chicks during one night. Maternal responses also emerged in non-laying hens but more gradually. In both groups, a decline in plasma testosterone occurred after the introduction of the chicks and, in the incubating hens, prolactin levels fell as they abandoned their nests.     

Reduction of horizontal transmission of avian leukosis virus subgroup J in broiler breeder chickens hatched and reared in small groups

Transmission of avian leukosis virus, subgroup J (ALV-J), from donor chickens inoculated as embryos to simulate congenital infection to uninfected hatchmates was studied in two strains of commercial broiler breeder chickens. Chicks of two commercial lines free of ALV-J became infected when hatched (1/2 lots positive) or reared (8/8 lots positive) in direct physical contact with ALV-J-infected donors. Infection also occurred when chicks were exposed in the hatchery to ALV-J-infected donors by cloacal swab transfer (2/2 lots positive), needle transfer during subcutaneous inoculation (2/2 lots positive), or ingestion of infected meconium (2/2 lots positive). However, transmission was delayed or prevented by wire partitions in the hatcher and rearing of small groups in cubicles, and rarely (1/10 lots positive) resulted from short-term direct or indirect contact. In a simulated field test, a flock of 503 broiler breeder chickens with an initial embryo infection rate of 4.6% was hatched and reared as 48 small groups to 4 weeks of age. Groups were tested at hatch and at 3 weeks, and 14 infected groups were eliminated. This flock tested negative for ALV-J infection from 4 to 32 weeks and did not transmit infection to progeny or develop tumours. A control group of 377 chickens with a similar initial infection rate was hatched and reared as a single group. This control flock transmitted virus to 5.7% of its progeny and about 5% of the hens developed tumours. The small-group hatching and rearing practices employed in these studies allowed for the accurate identification and removal of groups containing chickens infected prior to hatching and prevented horizontal transmission of ALV-J between uninfected and infected groups for at least 4 weeks. More importantly, application of these procedures successfully eradicated ALV-J in a single generation under laboratory conditions. This suggests that similar procedures could be a valuable adjunct to virus eradication programmes in the field.     

Dietary vitamin E in White Leghorn layer breeder hens: a strategy to combat aflatoxin B1-induced damage

Mycotoxins are unavoidable contaminants of animal and human feed and food respectively. This study was designed to investigate the protective activity of vitamin E (Vit E) in White Leghorn breeder hens and their progeny against aflatoxin B₁ (AFB₁)-induced damage. The results indicated a significant decrease in egg production and quality in the groups exposed to dietary AFB₁. A detectable amount of AFB₁ residue appeared in the eggs during the first week of mycotoxin exposure at levels ≥ 2.5 mg kg^?1, which reached its peak (0.403 ± 0.04 ng/g [mean ± standard deviation]) during the second week of the experiment (in the group fed 10 mg kg^?1). Feeding Vit E + AFB₁ resulted in higher AFB₁ residues (0.467 ± 0.03) when compared with the hens fed AFB₁ alone. The resistance of red blood cells to oxidative damage was decreased, while embryonic mortalities and deformities were increased in the AFB₁-fed groups. The protective effect of Vit E on these parameters was noted in the groups fed lower doses of AFB₁. After the withdrawal of mycotoxin-contaminated feed, most of the parameters returned towards normal within 2 weeks, except AFB₁ residues that were still detectable. From the findings of this study one can conclude that the addition of Vit E in the diet of hens provided only partial protection against AFB₁-induced damage.     

Evaluation of combined antibiotic and competitive exclusion treatment in broiler breeder flocks infected with Salmonella enterica serovar Enteritidis.

Strategic medication in breeding flocks of domestic fowl (Gallus gallus), using antimicrobial treatment followed by competitive exclusion, was evaluated in 13 trials between February and September 1993. In each trial, the flock had been confirmed as naturally infected with Salmonella enterica serovar Enteritidis and the effect of treatment was determined on salmonella isolation from tissues. Of 11 trials where enrofloxacin was used, a long-term reduction of salmonella was observed in two and a short-term reduction was measured in birds from another five trials. Salmonella Enteritidis was isolated from birds after treatment in four other trials with enrofloxacin and in two trials of medication with amoxycillin. After treatment with enrofloxacin significant reductions were found in the prevalence of 5. Enteritidis in tissues from birds, and in levels and prevalence of salmonellas in their environment. No salmonella was identified in statutory meconium samples taken from the hatched chicks derived from the flocks after treatment. The programme of antibiotic treatment and competitive exclusion offers an alternative to slaughter, but the approach must be part of a co-ordinated programme which will effect a decrease in the prevalence of 5. Enteritidis over time by contemporary use of disease security measures. The risk of development of antimicrobial resistance is also discussed.     

Potential for amelioration of aflatoxin B1-induced immunotoxic effects in progeny of white leghorn breeder hens co-exposed to vitamin E

Abstract

This study was designed to evaluate the protective activity of Vitamin E (Vit E) on the immunotoxic effects induced by aflatoxin B₁ (AFB₁) in the progeny of breeder hens. For this purpose, 192 White Leghorn (WL) layer breeder hens were divided into 12 groups (A–L) and then fed test diets for either 1, 2 or 3 weeks. Group A was kept on basal feed (2900 Kcal/kg metabolizable energy) and served as control, while group B was offered a feed supplemented with Vit E at 100?mg/Kg. Groups C–G were offered feed containing 0.1, 0.5, 2.5, 5.0, and 10.0?mg/Kg AFB₁, respectively, whereas groups H–L were offered the same dietary levels of AFB₁ along with 100?mg/Kg Vit E supplementation. Hatching eggs were shifted to an incubator on a weekly basis to get progeny chicks. Hatched chicks in each group were maintained on basal ration and then subjected to different immunological assays. Lymphoproliferative responses (against PHA-P), antibody titers (against SRBC), oxidative damage to RBC, as well as phagocytic and nitrite production potential of the peritoneal macrophages from the chicks, were all adversely impacted by hen exposure to the higher doses of AFB₁ or by increased intake (time) by the hens at a given dose of the toxin. No consistent ameliorative effects from Vit E were noted in these studies, i.e. effects seen against lower AFB₁ doses were no longer apparent with the highest doses of AFB₁. As such, for now it can be concluded that, with this particular single dose level of Vit E, AFB₁-associated immunotoxic effects in progeny chicks can potentially be mitigated by dietary intake of Vit E by their hen dams. However, this is clearly an outcome that is driven by the level of the mycotoxin present in the feed. Future studies need to examine what impact higher Vit E doses than those employed herein might have in these ameliorative outcomes.     

Vaccination of breeder hens with a polyvalent killed vaccine for pathogenic Enterococcus cecorum does not protect offspring from enterococcal spondylitis

Pathogenic strains of Enterococcus cecorum cause symmetrical paralysis in broilers due to infection of the free thoracic vertebra. The disease caused by pathogenic E. cecorum, known as enterococcal spondylitis or “kinky-back” continues to be responsible for significant losses to the broiler industry worldwide. In outbreaks of pathogenic E. cecorum, gut colonization and sepsis occur in the first three weeks-of-life. Since maternal antibodies are present during this period, we postulated that vaccination of breeders with a polyvalent killed vaccine would protect chicks from challenge. To test this hypothesis, representative isolates from seven genotype groups of pathogenic E. cecorum circulating in the US were chosen to produce adjuvanted killed vaccines (bacterins) and given to broiler-breeder hens. No single strain produced high titres of antibodies to all other strains; however, the combination of serologic reactivity of pathogenic isolates (designated SA3 and SA7) was sufficient to react with all genotypes. Vaccination of commercial broiler-breeder hens with a bacterin composed of SA3 and SA7 did not have any adverse effects. Vaccinated hens developed E. cecorum specific antibodies; however, no significant difference in survival was observed in infected embryos from hens in vaccine or adjuvant only groups. Chicks from vaccinated hens also failed to resist homologous or heterologous challenge during experimental infection. In a macrophage killing assay, pathogenic E. cecorum were found to evade opsinophagocytosis with elicited antibodies. These data suggest that pathogenic strains of E. cecorum possess virulence mechanisms that confound antibody-mediated opsinophagocytosis, complicating vaccine development for this pathogen of broilers.