Mathematical models to describe the growth curves of Vietnamese Ri chicken

Ri chicken is the most popular backyard chicken breed in Vietnam, but little is known about the growth curve of this breed. This study compared the performances of models with three parameters (Gompertz, Brody, and Logistic) and models containing four parameters (Richards, Bridges, and Janoschek) for describing the growth of Ri chicken. The bodyweight of Ri chicken was recorded weekly from week 1 to week 19. Growth models were fitted using minpack.lm package in R software and Akaike’s information criterion (AIC), Bayesian information criterion (BIC), and root mean square error (RMSE) were used for model comparison. Based on these criteria, the models having four parameters showed better performance than the ones with three parameters, and the Richards model was the best one for males and females. The lowest and highest value of asymmetric weights (α) were obtained by Bridges and Brody models for each of sexes, respectively. Age and weight estimated by the Richard model were 8.46 and 7.51 weeks and 696.88 and 487.58 g for males and for females, respectively. Differences in the growth curves were observed between males and female chicken. Overall, the results suggested using the Richards model for describing the growth curve of Ri chickens. Further studies on the genetics and genomics of the obtained growth parameters are required before using them for the genetic improvement of Ri chickens.

Occurrence of Chicken Infectious Anemia Virus in Industrial and Backyard Tunisian Broilers: Preliminary Results

Chicken infectious anemia virus (CIAV) is an economically important and widely distributed immunosuppressive agent in chickens. This study performed an epidemiological investigation on CIAV circulation in 195 Tunisian broilers, belonging to 13 lots from five industrial farms and in one rural farm. Fifteen animals were detected positive by a VP1 nested PCR. The amplicons were molecularly characterised by complete genome sequencing. All positive samples obtained in this study were from the rural farm, whereas the industrial farms sampled were negative. Nucleotide and amino acid sequence analyses showed a high degree of similarity among the sequences obtained, suggesting the circulation of a single CIAV strain in the positive lot. Phylogenetic analysis based on the CIAV VP1 nucleotide sequence and/or the complete genome showed that the sequences obtained in this study clustered with CIAV strains previously detected in Tunisia, Italy and Egypt, belonging to genogroup II. Our results highlight the need for constant CIAV surveillance in backyard chicken production.

Multidrug resistance, biofilm formation, and virulence genes of Escherichia coli from backyard poultry farms

Background and Aim: Backyard chicken flocks have traditionally been regarded as an essential food source in developed countries; however, they may act as reservoirs and spread various zoonotic bacterial pathogens. This study was designed to investigate the prevalence, phenotypic resistance, biofilm formation (BF), and pathotypes of Escherichia coli isolates from backyard poultry farms. Materials and Methods: Cloacal swabs (n=150) and internal organs (n=150) were collected from 30 backyard chicken flocks; 20 of them were experiencing systemic infection, and the other ten were apparently healthy. Samples were bacteriologically examined for E. coli isolation. Isolates were identified biochemically by the VITEK® 2 COMPACT system (BioMérieux, France). For molecular identification, 16S rRNA was amplified and sequenced. Ten antimicrobials were selected for E. coli antimicrobial susceptibility testing. The minimum inhibitory concentration for each antimicrobial was determined. The extended-spectrum β-lactamase activity in isolates was investigated using cephalosporin/clavulanate combination disks. The ability of isolates for BF was determined by the microtiter plate method. Thirteen virulence genes linked to different E. coli pathotypes and two serotype-related genes were investigated by real-time polymerase chain reaction. Results: Eighty-six E. coli strains were isolated from 30 backyard chicken flocks. The isolates were biochemically identified to the species level. Genetically, sequences of the 16S rRNA gene showed >98% identity with E. coli in the National Center for Biological Information database. The frequency of isolation from diseased flocks was significantly higher (p<0.05) than apparently healthy flocks; 63.9% of the isolates were recovered from cloacal swabs and 36.04% were recovered from internal organs. E. coli isolates showed high resistance to ampicillin (AMP; 75.6%), gentamicin (39.5%), and tetracycline (29.1%). However, none of the isolates were resistant to imipenem. A variable drug resistance profile for E. coli isolates was reported. Twenty-one (24.4%) isolates were sensitive to all ten antimicrobials. Seven (8.1%) isolates were resistant only to AMP, and 28 (32.6%) were resistant to two antimicrobials, whereas the remaining 30 (34.9%) isolates showed multidrug resistance (MDR). Of the 86 isolates, 8 (9.3%) were confirmed as extended-spectrum β-lactamase (ESBL)-producing E. coli by the combination disk diffusion method. All ESBL isolates were MDR with an MDR index of 0.5-0.6. Fifty-seven (66.3%) isolates were capable of forming biofilms; 22 (25.6%) of them were strong biofilm producers, 24 (27.9%) moderate producers, and 11 (12.8%) weak producers. A statistically significant pairwise correlation was obtained for MDR versus BF (r=0.512) and MDR index versus BF (r=0.556). Based on virulence gene profiles, five pathotypes were identified, including enteropathogenic E. coli (39.5%), avian pathogenic E. coli (32.53%), enterohemorrhagic E. coli (EHEC; 9.3%), enterotoxigenic E. coli (ETEC; 5.8%), and enteroaggregative E. coli (EAEC; 1.2%). The lower frequency of EAEC and ETEC was statistically significant than other pathotypes. Three isolates were identified as O157 based on the detection of the rbfO157 gene. Conclusion: This study reported a high prevalence of MDR, suggesting the misuse of antimicrobials in backyard chicken farms. The emergence of ESBL and EHEC isolates in backyard chickens is a public health concern. Furthermore, the backyard flocks environment may harbor different pathogenic bacteria that may enhance the persistence of infection and the transmission to in-contact humans. Regular monitoring for the occurrence of MDR and the zoonotic pathotypes among E. coli in backyard chicken flocks is recommended, as these bacteria can transmit to humans through food products or contaminated environments.

Seroprevalence of infectious bursal disease and its potential risk factors in backyard chicken production of Waliso district, South Western Shoa Zone, Ethiopia

A cross sectional study on infectious bursal disease was conducted in apparently healthy backyard chicken at Waliso district of Southwestern Shoa, central oromia, Ethiopia from from November, 2018 to October, 2019. A total of 282 chickens were randomly selected to estimate seroprevalence of IBD infection and to identify the likely potential risk factors for the disease. Serum samples collected and serological test conducted in laboratory at National Animal Health Diagnosis and Investigation Center Sebeta, Ethopia. Out of 282 serum samples tested 224 were positive for indirect ELISA technique and the overall seroprevalence of IBDV in the study area was found to be 79.43% at individual level. Educational level of owners, kebeles and flock size significantly affect seroprevalence of IBD in the study area. The effect of difference in managements like source of replacement, frequency of house cleaning, use of disinfectant and isolation practice has a significant effect on IBDV sero-prevalence. A lower seroprevalence of IBDV was reported in good hygienic level of house (26.7%) than poor level of chicken house hygiene (96.4%) with statistically significant difference (P < 0.05). The seroprevalence of IBDV in the present study associated with chicken management, flock size, owner education level and other animal related risk factors for occurrence of the disease. Therefore, awareness on chicken health management, and importance of immunization would help to minimize the prevalence of the disease and play crucial role in the control of the disease. Furthermore, characterizing virus strains circulating in the area in future study is recommended.

First isolation of atypical enteropathogenic Escherichia coli from geese (Anser anser domestica) and first description of atypical EPEC from turkeys and pigeons in Hungary

Background Escherichia coli is a bacterial species widely distributed among mammals and avian species, and also a member of the normal intestinal microbiota. However, some E. coli strains of different pathotypes can cause disease in both humans and animals. Atypical enteropathogenic E. coli (aEPEC) can infect both animals and humans or influence the severity of other ongoing infections. Results In the present study, a total of 332 samples were collected from ducks, geese, turkeys, chickens, and pigeons from the Hungarian Veterinary Diagnostic Directorate, two slaughterhouses, two pigeon keepers and one backyard chicken farm. E. coli was isolated and verified from 319 samples. The isolates were screened by PCR for diarrheagenic E. coli pathotypes. Altogether seven atypical enteropathogenic E. coli (aEPEC) strains were identified: two from four-week-old dead turkeys, two from force-fed geese, and three from pigeons. No further pathotypes were identified in the collection. The atypical EPEC strains were classified phylogenetically to B1, B2, and F, and four out of the seven aEPEC isolates proved to be multidrug resistant. Serotypes of aEPEC strains were uniform collected from same farms and showed diversity between their origins with O76, O145, O109 serogroups. Conclusions This is the first report in the literature about aEPEC in goose (Anser anser domestica). Furthermore, this is the first isolation of aEPEC from turkeys and pigeons in Hungary. The uneven distribution of aEPEC in different age groups of poultry suggests that aEPEC disappears with growing up, but stress (e.g.: force-feeding) and concurrent diseases might promote its reappearance in the intestine.

Simultaneous Detection of Velogenic Genotype XIII 2.2 Avian Avulavirus Type 1 (AAvV-1) From Spot-billed Pelican and Backyard Chicken: Implications to the Viral Maintenance and Spread

The present study demonstrates simultaneous isolation of genetically similar velogenic Avian Avula virus-1 from an apparently healthy spot- billed pelican and a naturally infected backyard chicken in the adjacent vicinity. A total of fourty eight cloacal swab samples from migratory birds (Painted storks, n=32 and Spot billed pelicans, n=16) at the Telineelapuram bird sanctuary in Andhra Pradesh, India and tissue samples of dead backyard chicken were collected. Two isolates were recovered, one each from a spot billed pelican (MIG-9) and a dead chicken (SKLM-1). The isolates were confirmed as velogenic based on mean death time, intra cerebral pathogenicity index and the putative fusion protein cleavage site (113R-R-K-R-F117). Phylogenetic analysis based on full- length fusion and attachment (HN) proteins classified the isolates into genotype XIII, sub- genotype 2.2. Sequence analysis revealed that the pelican and chicken isolates were 100% identical. The study isolates demonstrated multiple amino acid substitutions at several critical domains of F and HN proteins when compared with the current vaccine strains. Pathogenic and transmission potential of the AAvV-1 isolates was evaluated in three- week old chicken and the isolates proved to be highly virulent to chicken. To the best of our knowledge, this is the first evidence for the role of spot-billed pelicans in the maintenance of virulent AAvV-1 and its transmission to chicken. This study further highlights the role of wild birds in AAvV-1 transmission and the need for enhanced biosecurity in commercial poultry operations.

Geographical Distribution and Impact of Backyard Chicken Varieties in India: A Retrospective Assessment

The data collected on distribution of improved chicken varieties over the past 25 years (1992–2017) from the ICAR-Directorate of Poultry Research, Hyderabad (ICAR-DPR), poultry seed project centres (PSP) and other Government agencies who had taken parent stock from ICAR-DPR, were analysed to estimate the impact of the backyard poultry. A total of 7.56 million improved chicken germplasm (27%) to 20.37 thousand stakeholders from ICAR-DPR, Hyderabad and 1.7 million (6.09 %) to 28.38 thousand stakeholders from PSP were distributed during 1992–2017. Other agencies distributed 18.67 million (66.85%) germplasm to 311.17 thousand stakeholders. The majority of the beneficiaries were from southern region (35%) followed by central (23.4%) and eastern (20.8%) region of the country. Of the total varieties, Vanaraja constituted about 52% of the total germplasm followed by Gramapriya (38%). The share of improved chicken germplasm increased from 0.01 (1992) to 0.41% (2012) in the poultry population of India i.e., from 100 to 9433 indices as compared to 100 to 244 of the country. Contribution of improved germplasm to the Indian economy increased from 1.9 (8th plan) to 62. 5 (12th Plan) million USD. The total contribution during the 25 years was estimated to be about 168.7 million USD to Indian economy. Higher productivity of birds increased the income leading to socio-economic development of farmers. The study concluded that backyard poultry significantly contributed to the national economy and improved the livelihoods of the rural and tribal people, which needs to be further strengthened across the different geographical regions of the country.

Immunogenicity and Protective Efficacy of Iron-inactivated Pasteurella multocida A:1 Vaccine against Fowl Cholera in Backyard Chicken

Background: Fowl cholera is a highly fatal, contagious bacterial disease that incurs significant economic loss in commercial as well as back-yard poultry. Vaccination is the most effective way in controlling this disease. In this study, we prepared and evaluated the immunogenicity of iron- inactivated Pasteurella multocida A:1 vaccine and its protective efficacy against fowl cholera experimental infection in backyard chicken.Methods: Scaled up Pasteurella multocida A:1 culture with 5 X 108 CFU/ml equivalent to 2.5 mg of antigen per dose was used for preparation of experimental vaccines. Formalin inactivated and mixed with APS adjuvant (FIA), formalin inactivated-Freund adjuvant (FIF), Iron inactivated and adjuvanted with iron (III), Iron inactivated from iron supplemented media and adjuvanted with iron (ISII) and commercial oil emulsion vaccine (CV) were used in the study. A total of 120 Vanaraja birds (n=20/group) of 2 weeks age were immunized with these vaccine and booster were given at 3rd and 6th week with respective vaccine. Specific antibody titers were assessed by iELISA in the serum at weekly intervals. The birds were challenged (n=6 /group) with 5x104 CFU/ml of virulent isolate by intraperitoneal route and morbidity, mortality percentage were observed.Result: Protective antibody titers were induced by iron inactivated vaccine from 4th week of immunization and upon booster doses it induced significantly higher (P less than 0.05) antibody response. The iron inactivated experimental vaccine gave equivalent protection as that of commercial vaccine upon challenge infection.