Pathogenicity of Salmonella enteritidis phage types 4, 8, and 23 in broiler chicks.

Four hundred fifty day-old Hubbard broiler chicks were subdivided into 15 groups of 30 chicks each. Six groups of chicks received 0.5 ml of broth culture containing 5 x 10(6) colony-forming units (CFU) of Salmonella enteritidis (SE) phage types (PTs) 4, 8, and 23 by crop gavage. Similarly, six other groups received 0.5 ml containing 5 x 10(8) CFU of SE. One group was inoculated with 0.5 ml containing 5 x 10(6) CFU of Salmonella pullorum, and another group received 0.5 ml containing 5 x 10(8) CFU of S. pullorum. A group of 30 chicks were kept as uninoculated controls. Chicks were observed daily for clinical signs and mortality. All birds were weighed at 7, 14, and 21 days postinoculation 21 (DPI). Four chicks were randomly selected from each treatment group, euthanatized, and necropsied at 7 and 14 DPI. Gross lesions were recorded and selected tissues were collected for histopathology. The higher rates of illness and mortality were observed in chicks inoculated with 5 x 10(6) and 5 x 10(8) CFU of S. pullorum, followed by SE PT4 of human origin and SE PT4 of chicken origin. Moderate to high mortality was observed in chicks inoculated with the higher dose of SE isolates that belonged to PT8 and one SE of PT23. Variable mortality was evident in groups inoculated with the lower dose of salmonella. The most consistent gross and histopathologic changes, including fibrinous pericarditis and perihepatitis, were seen in the dead birds from various treatment groups. The lower mean body weights were present in all treatment groups compared with uninoculated controls. No illness or mortality was observed in uninoculated control groups.     

Protection of neonatal broiler chicks against Salmonella Typhimurium septicemia by DNA containing CpG motifs

Oligodeoxynucleotides (ODN) containing cytosine-phosphodiester-guanine (CpG-ODN) motifs have been shown to stimulate the innate immune system against a variety of bacterial and protozoan infections in a variety of vertebrate species. The objective of this study was to investigate the immunostimulatory effect of CpG-ODN in neonatal broilers against Salmonella Typhimurium septicemia. Day-old broiler chicks, or embryonated eggs that had been incubated for 18 days, received 50 microg of CpG-ODN, 50 microg of non-CpG-ODN, or saline. Four days after exposure to CpG-ODN or day 2 posthatch, 1 x 10(6) or 1 x 10(7) colony-forming units (cfu) of a virulent isolate of Salmonella Typhimurium was inoculated by the subcutaneous route in the neck. Clinical signs, pathology, bacterial isolations from the air sacs, and mortality were observed for 10 days following challenge with Salmonella Typhimurium. The survival rate of birds in groups receiving either non-CpG-ODN or saline following Salmonella Typhimurium infection was 40%-45%. In contrast, birds receiving CpG-ODN had significantly higher survival rate of 80%-85% (P < 0.0001). Bacterial loads and pathology were low in groups treated with CpG-ODN compared to the groups receiving saline or non-CpG-ODN. Colony-forming units of Salmonella Typhimurium in the peripheral blood were significantly lower in birds treated with CpG-ODN compared to the group that received saline. This is the first time that CpG-ODN has been demonstrated to have an immunoprotective effect against an intracellular bacterial infection in neonatal broiler chickens following in ovo delivery.     

Pathogenicity of different serogroups of avian salmonellae in specific-pathogen-free chickens.

The pathogenicity of one isolate of Salmonella typhimurium, four isolates of Salmonella heidelberg, three isolates of Salmonella kentucky, two isolates of Salmonella montevideo, one isolate of Salmonella hadar, and two isolates of Salmonella enteritidis (SE), one belonging to phage type (PT)13a and the other to PT34, was investigated in specific-pathogen-free chicks. Three hundred eighty-four chicks were separated into 16 equal groups of 24 chicks. Thirteen groups were inoculated individually with 0.5 ml of broth culture containing 1 x 10(7) colony-forming units (CFU) of either S. typhimurium (one source), S. heidelberg (four sources), S. montevideo (two sources), S. hadar (one source), S. kentucky (three sources), SE PT 13a (one source) or SE PT 34 (one source) by crop gavage. Two groups of 24 chicks were inoculated in the same way with 1 x 10(7) CFU of SE PT4 (chicken-CA) and Salmonella pullorum. Another group of 24 chicks was kept as an uninoculated control group. The chicks were observed daily for clinical signs and mortality. Isolation of salmonella was done from different organs at 7 and 28 days postinoculation (DPI). All the chicks were weighed individually at 7, 14, 21, and 28 DPI. Two chicks chosen at random from each group were euthanatized and necropsied at 7 and 14 DPI and all the remaining live chickens, at 28 DPI. Selected tissues were taken for histopathology at 7 and 14 DPI. Dead chicks were examined for gross lesions and tissues were collected for histopathology. Chicks inoculated with S. pullorum had the highest mortality (66.66%), followed by S. typhimurium (33.33%). Chicks inoculated with S. heidelberg (00-1105-2) and SE PT4 (chicken-CA) had 12.5% mortality and 8.3% mortality, respectively, with SE PT 13a. Ceca were 100% positive for salmonellae at acute or chronic infection compared with other organs. Mean body weight reduction ranged from 0.67% (inoculated with S. kentucky 00-926-2) to 33.23% (inoculated with S. typhimurium 00-372) in the inoculated groups at different weeks compared with uninoculated controls. Gross and microscopic lesions included peritonitis, perihepatitis, yolk sac infection, typhilitis, pneumonia, and enteritis in some groups, especially those inoculated with S. typhimurium, S. heidelberg (00-1 105-2), SE PT4 (chicken-CA), and S. pullorum.     

Yolk sac, body dimensions and hatchling quality of ducklings, chicks and poults

1. One-day-old chicks of Pekin duck, turkey, layer fowl and broiler fowl were examined for bacteria in the yolk sac and yolk fluid. 2. Whole hatchling, yolk-free hatchling and yolk sac weights were recorded for all species along with crown-rump length and beak-tip to toe-tip length. 3. Bacteriology revealed positive results for the whole yolk sacs of 43 to 64% of the birds in the sample of ducklings, poults and layer chicks. Broiler chicks had a 6.6% incidence of bacteria isolated from the whole yolk sac. By contrast, there were very few positive results from swabs of yolk fluid for any of the bird types. 4. The presence of bacteria in the yolk sac of hatchlings suggests that there is colonisation, rather than infection, of the yolk sac membrane during the hatching period or the first few hours post-hatching. Isolation of bacteria from the yolk sacs of young chicks might no longer be considered as solely indicative of yolk sac infection but further research is required to confirm this result. 5. Contrary to what is being suggested in commercial practice relationships between linear dimensions and hatchling weight suggest that measurement of chick length is at best a very crude measure of chick quality.     

Natural Occurrence of Campylobacter Species,Salmonella Serovars,and Other Bacteria in Unabsorbed Yolks of Market-Age Commercial Broilers

In the developing avian embryo, the main energy source is the yolk. Toward the end of the incubation period, the remaining yolk sac is internalized into the abdominal cavity. At hatch, the remaining yolk comprises 20% of the chick's BW and provides the nutrients needed for maintenance. Posthatch, chicks rapidly initiate the transition from yolk dependence to the utilization of exogenous feed. However, at present, it is not known what types of bacteria are found to be associated with unabsorbed yolk sacs from market-age broilers. For Experiment 1, one hundred 6-wk-old defeathered broiler carcasses were obtained from a commercial processing facility during each of 3 visits. In the second experiment, one hundred 8-wk-old defeathered broiler carcasses were obtained from a different commercial processing plant on 4 separate occasions. For both experiments, each carcass was aseptically opened and inspected for the presence of an unabsorbed yolk sac. Three to 5 carcasses containing a free-floating yolk sac (within the abdominal cavity) and the yolk stalk (without a yolk sac) and 3 to 5 carcasses containing an attached yolk and yolk stalk from each repetition were randomly selected and analyzed for levels and types of total aerobic bacteria (APC), Enterobacteriaceae (ENT), and for the presence of Campylobacter spp. and Salmonella serovars. The APC ranged from log 3.3 to >log 6.0, and the ENT ranged from log 2.8 to >log 6.0. Staphylococcus spp. and Streptococcus spp. were the predominant organisms in APC, whereas Escherichia coli and Hafnia alvei were found to comprise the ENT. Campylobacter spp. was found in 29% of the yolk stalks, 32% of the attached yolk sacs, and 13% of the free-floating yolk sacs. All Campylobacter isolates were determined to be Campylobacter jejuni, except for 1 attached yolk and yolk stalk, which was Campylobacter coli. Salmonella serovars were found in 26% of the yolk stalks, 48% of the attached yolk sacs, and 23% of the free-floating yolk sacs, and the majority of Salmonella isolates were Salmonella Typhimurium. The significance of these bacterial reservoirs and carcass contamination during processing is yet to be determined.     

Influence of Water Provision to Chicks Before Placement and Effects on Performance and Incidence of Unabsorbed Yolk Sacs

A study was conducted to determine the effect of water provision to chicks before placement on performance and the incidence of unabsorbed yolk sacs. To accomplish this, a device was used that was designed to deliver water to chicks in chick baskets during holding at the hatchery and transportation to the growout house. Commercial chicks were obtained from the hatchery and held for either 24 or 48 h with or without access to water before placement. Chicks were then distributed into floor pens with ad libitum access to feed and water. At 6 wk of age, broilers were processed, and intestines were evaluated for presence or absence of an unabsorbed yolk sac and intestinal breaking strength. Body weight at placement was 2 to 6 g greater for chicks given access to water; however, this difference was not observed at any other time during the growout. Water provision during holding had no affect on feed consumption, mortality, or the birds’ ability to completely absorb the yolk sac during the 6 wk growout. Incidence of unabsorbed yolk sacs in 6 wk old birds ranged from 15 to 28%. Moreover, presence or absence of an unabsorbed yolk sac had no effect on intestinal breaking strength. Data from the present study demonstrates that providing chicks with water before placement does not influence performance, intestinal breaking strength, or the incidence of unabsorbed yolk sacs.     

Efficacy of Calcium Fosfomycin for the Treatment of Experimental Infections of Broiler Chickens with Escherichia Coli O78:K80

Two trials were made to assess the efficacy of including calcium fosfomycin in the drinking water or in the feed for four days to control the adverse effects of experimentally induced colibacillosis in broiler chickens. Trial 1 had five groups of 15 chicks each: one group of negative controls; an untreated infected control group and three groups treated with 50, 100 or 200 ppm of calcium fosfomycin in drinking water. Trial 2 had the same groups but the antibiotic was incorporated into the feed. The chickens were infected via their air sacs with 1.7 x 10⁸–3.6 x 10⁸ CFU/chick of Escherichia coli O78:K80. The morbidity and mortality, a score for the gross lesions, the relative weight of the liver and spleen, performance and re-isolation of the challenge bacteria were recorded. Calcium fosfomycin in the drinking water controlled the colibacillosis, particularly in the group treated with 200 ppm. However, no effect of the antibiotic was seen when calcium fosfomycin was incorporated into the feed, the mortality, score of lesions and re-isolation of E. coli from the organs in the three treated groups being similar to those for the infected unmedicated group. The amount of antibiotic ingested in trial 1 was three times more than in trial 2. These results suggest that calcium fosfomycin is best used in the drinking water for the treatment of colibacillosis.     

Experimental studies on Yersinia enterocolitica infection in chickens exposed at 1-day old

1. Seventy 1-d-old broiler chicks were experimentally inoculated orally with Yersinia enterocolitica serotype 0:3 (1.4 x 10(11) cells/chick), 0:8 (1.6 x 10(11) cells) and 0:9 (8.0 x 10(10) cells) with or without sodium bicarbonate solution (10 g/l). 2. None of the chicks showed any overt clinical signs or pathological lesions although the organism was demonstrated in the ileum and shedding was observed up to 13 d after exposure. 3. The serotype, dose of Y. enterocolitica and administration of NaHCO3 solution had no significant effect on the weight gain of exposed broiler chicks. 4. Y. enterocolitica was isolated from the liver, spleen, heart and gall bladder of infected chicks 70 d after exposure. 5. Although broiler chicks appear resistant to high doses of Y. enterocolitica by the oral route, detection of the organism in the organs of infected chickens is of public health significance.     

Clinical and pathological features of Aspergillus fumigatus infections in poultry in southern Nigeria

This study was undertaken to supply information on Aspergillus fumigatus infection of poultry in Nigeria. The disease in broiler chicks was characterized by gasping, droopiness, emaciation and heavy mortality while affected grower chickens showed emaciation, weakness, diarrhoea and 17 per cent mortality. The disease was sporadic in laying flocks. Granulomatous nodules were observed in birds that died in each outbreak. The nodules were numerous and affected mainly the lungs and thoracic air sacs in the broiler chicks while only few large nodules were observed mainly in the abdominal air sacs in the layers.     

Characterisation of an infectious bronchitis virus isolated from vaccinated broiler breeder flocks.

Four apparently serologically closely related isolates of infectious bronchitis virus were obtained from two flocks of vaccinated broiler breeders, one mile apart, which were experiencing increased mortality and decreases in egg production. The isolates were serologically distinct from isolates previously described and capable of causing characteristic infectious bronchitis-like respiratory infection in young chicks. In one experiment, the H120 vaccine strain of the virus did not protect the trachea against challenge with the new isolates 21 days later.     

Effect of ochratoxin A on Escherichia coli-challenged broiler chicks

A study was conducted to evaluate the effects of ochratoxin A (OA) on Escherichia coli-challenged broiler chickens. Day-old broiler chicks were separated into two groups of 92 chicks each, with one group fed a control mash diet, and the other fed a mash diet containing 2 ppm OA. On day 14, each group was further separated into two groups, with one group inoculated with E. coli O78 (1 x 10(7) colony-forming units/0.5 ml), whereas the other group was not inoculated with E. coli. After E. coli inoculation on day 14, four birds from each group were euthanatized at 1, 2, 3, 5, 7, 10, 14, and 21 days postinoculation. Escherichia coli infection caused dullness, depression, huddling, and diarrhea. Mortality was 14.3% in chicks infected with E. coli but fed no OA. Mortality increased to 35.7% in chicks fed OA and infected with E. coli. Decreased body weight and reduced feed intake were observed in chicks fed OA, and the effects were more pronounced in chicks fed OA and infected with E. coli. Increased serum levels of aspartate aminotransferase, alanine aminotransferase, uric acid, and creatinine and decreased levels of total proteins, albumin, globulins, calcium, and phosphorus were observed in OA-fed birds. Escherichia coli infection did not cause significant alteration in any of the serum biochemical parameters. The presence of OA in poultry rations increased mortality and the severity of an E. coli infection.     

Effect of selenium and vitamin E content of the maternal diet on the antioxidant system of the yolk and the developing chick

1. The effects of selenium and vitamin E supplementation of the maternal diet on their transfer to the egg yolk and tissues of the newly hatched chick and on the development of the antioxidant system in the chick liver in early postnatal life were investigated. 2. One hundred Cobb broiler breeder hens were divided into 10 equal groups and housed in pens at 25 weeks of age. Each hen received 1 of the treatment diets which included 0.2 or 0.4 mg/kg selenium, 40, 100, 200 mg/kg vitamin E or their combination. After 6 weeks, the hens were artificially inseminated once per week. From week 8, eggs were collected and placed in an incubator. After hatching, chicks from each group were reared (under standard commercial conditions) to 10 d of age. The chicks were fed on a standard starter commercial broiler diet. At the time of hatching, and at 5 and 10 days old, 4 chicks from each group were sacrificed and blood, liver and brain were collected for the subsequent biochemical analyses. 3. The inclusion of organic selenium or vitamin E in the commercial diet significantly increased their concentration in the egg and in the liver of 1-d-old chicks obtained from the eggs enriched with these substances. A positive effect of such dietary supplementation was seen at d 5 and d 10 of postnatal development. 4. There was a positive effect of selenium supplementation of the maternal diet on glutathione concentration in the liver of 1-d-old and 5-d-old chicks. A combination of a dietary selenium supplementation with high vitamin E doses further increased glutathione concentration in the liver. Dietary selenium supplementation significantly increased selenium-dependent glutathione peroxidase (Se-GSH-Px) activity in the liver of the 1-d-old and 5-d-old chicks and decreased liver susceptibility to peroxidation. 6. It is concluded that the nutritional status of the laying hen determines the efficiency of the antioxidant system throughout embryonic and early postnatal development of the offspring.     

Necrotic hepatitis due to Clostridium perfringens infection in newly hatched broiler chicks

Multiple necrotic hepatitis lesions of 5 newly hatched broiler chicks in three flocks derived from two hatcheries were examined pathologically. The livers were brittle, and multiple yellowish or green foci were scattered on the surface and cut surface. The main histological finding was well demarcated multi-focal necrosis in the liver. Many Gram-positive large bacilli that reacted positively with polyclonal anti-Clostridium perfringens serum were observed in necrotic areas.     

Guar meal ameliorates Eimeria tenella infection in broiler chicks

Guar meal contains relatively high levels of saponins, which are known to have antiprotozoal activity and may be effective against coccidiosis. A 2x2 factorial experiment investigated the impact of guar meal (0 or 5%) corn-soy-based starter broiler diets on chicks unchallenged or challenged with Eimeria tenella. At 1 day of age, 120 unsexed RossxRoss broiler chicks were randomly distributed among four treatment groups. Chicks were challenged with 5x10(3) sporulated oocysts of E. tenella in 0.5ml at 10 days of age by oral gavage. Weekly body weight, body weight gains, feed conversion ratio and mortality rate were recorded for chicks fed from 0 to 21 days of age. Oocysts shed per gram feces were recorded from 6 to 10 days post-challenge. Results showed that challenged chicks fed 0% guar meal had significantly higher oocysts per gram shed in feces than the other groups. No significant differences among treatment groups in mortality rate were observed. Body weights of unchallenged and challenged chicks fed 0% guar meal were significantly higher than those fed 5% guar meal at 2 weeks of age. Results indicated that including 5% guar meal in the diet of chicks challenged with E. tenella decreased oocysts shed per gram feces and prevented bloody diarrhea, but without affects on body weight and feed conversion ratio at 11 days post-challenge.     

L-Leucine In Ovo Administration Causes Growth Retardation and Modifies Specific Amino Acid Metabolism in Broiler Embryos

L-Leucine (L-Leu) in ovo administration was demonstrated to afford thermotolerance and modified amino acids metabolism in post-hatched broiler chicks under heat stress. This study aimed to investigate the changes in embryonic growth and amino acid metabolism after in ovo injection of L-Leu. Fertilized broiler eggs were subjected to in ovo injection of sterile water or L-Leu on embryonic day (ED) 7. The weight of embryos and yolk sacs were measured on ED 12, 14, 16, and 18. Plasma and livers were collected on ED 14 and 18 for free amino acid analysis. The weight and relative weight of embryos were significantly lowered by in ovo administration of L-Leu, but those of yolk sacs were not altered. Moreover, L-Leu in ovo injection significantly reduced the plasma proline concentration during embryogenesis and increased the plasma concentrations of tyrosine (Tyr) and lysine (Lys) in ED 18. Hepatic Lys concentration was also significantly increased by L-Leu in ovo injection. Interestingly, Leu concentrations in the plasma and liver were not affected by L-Leu administration. These results indicated that in ovo administered L-Leu was metabolized before ED 14 and affected embryonic growth and amino acid metabolism during embryogenesis.     

Genomic identification and characterization of avian adenoviruses associated with inclusion body hepatitis.

Four pathogenic avian adenovirus isolates associated with inclusion body hepatitis and mortality in commercial broiler chicks and chickens were characterized and identified. These group I avian adenovirus isolates were classified as group E (serotypes 6, 7, 8, and 9) avian adenoviruses on the basis of the restriction enzyme patterns of their viral DNA. Isolate 3718 was neutralized by a serotype 6 reference avian adenovirus antiserum and isolates 8193, 8380, and 8565 were all neutralized by a serotype 8 reference avian adenovirus antiserum by virus neutralization assays. Infectivity and virulence such as mortality, hemorrhages, enlarged green livers with intranuclear inclusion bodies, stunting, intestinal sloughing, and poor feathering were observed in specific-pathogen-free chicken embryos and were identical for all four isolates when embryos were inoculated via the yolk sac and/or chorioallantoic membrane. Complete mortality was observed within 72 hr postinoculation in specific-pathogen-free (SPF) chickens inoculated intramuscularly for all four avian adenovirus isolates.     

Efficacy of a commercial competitive exclusion product against Campylobacter jejuni

1. Newly-hatched broiler chicks were treated orally with a commercial competitive exclusion product (Broilact) in 3 replicate trials 2. After 24 h the treated chicks and untreated control chicks were challenged orally with approximately 10(4) cfu of Campylobacter jejuni. 3. The caeca of the birds were examined quantitatively for campylobacter 12 d after the challenge. 4. In 3 separate trials, the treatment prevented or reduced colonisation of the challenge organisms in the caeca. The percentage of colonised birds varied from 0% to 62% in the treated groups and was 100% in the control groups. The average number of campylobacter was considerably lower in the treated groups than in the control groups.     

Effect of BioSentry 904 and ethylenediaminetetraacetic acid-tris disinfecting during incubation of chicken eggs on microbial levels and productivity of poultry

Proper sanitation practices and the use of efficacious disinfectants in a hatchery have an effect on chick quality. Aerosol bacterial counts, egg moisture loss, hatchability, chick quality, and broiler productivity were evaluated when egg surfaces were contaminated by immersion of each egg into a broth medium containing a field isolate of Pseudomonas aeruginosa and incubated with exposure to one of three disinfectant treatments administered by fine spray: distilled water, BioSentry 904 (904), and a 1:1 ratio of 904 and ethylenediaminetetraacetic acid (EDTA)-Tris. The aerosol bacteria levels were statistically greater on day 21 of incubation in the group treated with distilled water than in those receiving disinfectants. Overall hatch of fertile eggs and egg moisture loss were comparable among all three treatments. At 1 day of age, the chicks incubated with 904 had a statistically lower yolk sac contamination rate than those incubated with 904+EDTA-Tris or distilled water. The 2-wk mortality rates, body weights, feed conversion ratios, yolk sac weights, and yolk sac contamination rates were all similar among the three treatments.     

Vaccination of one-day-old broiler chicks against infectious coryza

In order to evaluate the protection conferred by an experimental inactivated vaccine against infectious coryza, three challenge trials were undertaken using 112 1-day-old broilers. The vaccine "Hepa Inmuno NC" included bacterial antigens of Avibacterium paragallinarum (serogroups A, B, variant B, and C) as well as antigens of Newcastle virus and hepatitis virus. Fifty-six broiler chicks were vaccinated at the first day of life at the hatchery while another 56 chicks were left unvaccinated. Three infection trials were conducted simultaneously using each of the three serogroups A, B, or C of Av. paragallinarum. In each trial, 17 vaccinated and 17 unvaccinated broilers were used. Challenge was performed at day 31 of life by injection, into the left infraorbital sinus, of approximately 1 x 10(5) colony forming units of the corresponding Av. paragallinarum strain. Clinical signs were recorded on day 2 postchallenge. All broilers were euthanatized and both infraorbital sinuses were bacteriologically examined for the presence of Av. paragallinarum on day 5 postchallenge. In comparison with the unvaccinated broilers, the vaccine significantly reduced the number of broilers with clinical signs after challenge with serogroup B, and significantly fewer vaccinated broilers were positive for the presence of Av. paragallinarum after challenge with serogroup C. On the other hand, no significant protection was observed when broilers were challenged with Av. paragallinarum from serogroup A. Despite the high infection rates in vaccinated chicks after an experimental infection with Av. paragallinarum, it was possible to reduce colonization of Av. paragallinarum (serogroup B) and clinical signs (serogroup C) in broiler chicks by vaccination at the first day of life. Further cross-protection trials should be done, including other Av. paragallinarum strains in the vaccine, especially those from serogroup A.     

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.