Time filter

Source Type

Durham, NC, United States

Sokale A.O.,Mississippi State University | Peebles E.D.,Mississippi State University | Stayer P.A.,Sanderson Farms Inc | Cummings T.S.,Zoetis Global Poultry | Wills R.W.,Mississippi State University
International Journal of Poultry Science | Year: 2013

The effect of feeding 3-nitro-4-hydroxyphenylarsonic acid (3-nitro) in broiler diets during low (May) and high (July) temperature months on the incidence of gastrocnemius tendon rupture (GTR) was evaluated in this study. All observations were made at a single processing plant during the months of May and July, 2010. The average live body weight (BW) of birds processed in May and July were 3.8 and 3.6 kg, respectively. The birds processed in May were fed 3-nitro in starter and grower diets (22 g/ton), whereas birds processed in July were fed 3-nitro in grower (34 g/ton) and finisher (22 g/ton) diets. Affected gastrocnemius tendons were classified as fibrosed and trimmables tendons, with trimmables subdivided into acute or chronic tendons. Data analysis by Poisson regression showed higher incidences of acute and fibrosed tendons in the month of May when compared to the month of July. Although GTR can be caused by pathogenic and non-pathogenic factors, in this field study a higher incidence of GTR observed in birds reared during low temperature months may be associated with a heavier live BW of the birds and the introduction of 3-nitro early (starter diet) in the grow-out period. © Asian Network for Scientific Information, 2013. Source

Gimeno I.M.,North Carolina State University | Faiz N.M.,North Carolina State University | Cortes A.L.,North Carolina State University | Barbosa T.,Zoetis Global Poultry | And 2 more authors.
Avian Diseases | Year: 2015

Administration of Marek's disease (MD) vaccines in ovo has become a common practice for the poultry industry. Efficacy of MD vaccines is very high, even though they are administered to chicken embryos that are immunologically immature. We have recently demonstrated that in ovo vaccination with Turkey herpesvirus (HVT) results in increased activation of T cells at hatch. Our previous results suggested that in ovo vaccination with HVT might have a positive impact not only on MD protection but also on the overall maturity of the developing immune system of the chicken (Gallus gallus domesticus). The objective of this study was to evaluate the effect of administration of HVT at 18 days of embryonation (ED) on the maturation of the embryo immune system. Four experiments were conducted in Specific-Pathogen-Free Avian Supplies (SPAFAS) chickens to evaluate the effect of administration of HVT at 18 ED on the splenic cell phenotypes at day of age (experiment 1) and on the ability of 1-day-old chickens to respond to various antigens compared with older birds (experiments 2 and 3). In addition, a fourth experiment was conducted to elucidate whether administration of other serotype's MD vaccines (CVI988 and SB-1) at 18 ED had the same effect as HVT on the spleen cell phenotypes at day of age. Our results demonstrated that 1-day-old chickens that had received HVT in ovo (1-day HVT) had higher percentages of CD45+, MHC-I+, CD45+MHC-I+, CD3+, MHC-II+, CD3+MHC-II+, CD4+, CD8+, and CD4+CD8+ cells in the spleen than 1-day-old sham-inoculated chickens (1-day sham). Moreover, spleens of 1-day HVT chickens had greater percentages of CD45+MHC-I+ cells and equal or greater numbers of CD4+CD8- and CD4-CD8+ cells than older unvaccinated chickens. In addition, administration of HVT at 18 ED rendered chicks at hatch more responsive to unrelated antigens such as concavalin A, phytohemagglutinin-L, and keyhole limpet hemocyanin. Administration of MD vaccines of other serotypes had an effect, although less remarkable than HVT, on the spleen cell phenotypes at hatch. Vaccines of all three serotypes resulted in an increased percentage of MHC-I+, CD45-MHC-I+, CD4-CD8+, and CD8+ cells, but only HVT resulted in a higher percentage of CD45+, CD45+MHC-I+, CD3+MHC-II+, and CD4+CD8-cells. Results of this study show that it is possible to hasten maturation of the chicken embryo immune system by administering HVT in ovo and open new avenues to optimize the procedure to improve and strengthen the immunocompetency of commercial chickens at hatch. © 2015 American Association of Avian Pathologists. Source

Gimeno I.M.,North Carolina State University | Cortes A.L.,North Carolina State University | Faiz N.M.,North Carolina State University | Barbosa T.,Zoetis Global Poultry | Villalobos T.,Zoetis Global Poultry
Avian Diseases | Year: 2015

Marek's disease (MD) strain CVI988 is the most-protective commercially available vaccine against very virulent plus (vv+) Marek's disease virus (MDV). However, its use in meat-type chickens has been controversial. While several countries have been using CVI988 for more than 40 yr, others do not authorize its use or it is restricted mainly to layers. The use of CVI988 in meat-type chickens will be necessary in the future in areas where other vaccine protocols fail. The objective of this study was to evaluate factors (vaccine dose, vaccine origin, chicken genetics, age and route of vaccination, and combination with other MD vaccines) influencing the efficacy of CVI988 against MD in meat-type chickens. Three animal experiments were conducted in which various vaccine protocols using CVI988 were tested for their protection against challenge with vv+ strain 648A by contact at day of age. Experiments 1 and 2 were to compare the efficacy of CVI988 vaccines from three different origins (CVI988-A, CVI988-B, and CVI988-C) and evaluate the effect of vaccine dose and chicken genetics. Experiment 3 was to evaluate the effect of adding CVI988 vaccine to various vaccine protocols using other MD vaccines of serotypes 2 (SB-1) and 3 (rHVT). Our results show that, regardless of the origin of the vaccine, protection against early challenge with 648A was good when vaccines were administered at a high dose (>3000 plaque-forming units [PFU]). Differences among vaccines, however, were detected even when using a high dose in experiment 2 (vaccine CVI988-B conferred higher protection than did CVI988-C) but not in Experiment 1 (CVI988-B was compared to CVI988-A). The use of a fixed low dose (2000 PFU) of vaccine resulted in reduction in protection, and such reduction was more remarkable when using CVI988-A. No statistically significant differences were found when we compared the efficacy of CVI988 in two different genetic lines of broiler chickens (G1 and G2). Vaccination protocols that included CVI988 had better protection than protocols that only included MD vaccines of serotypes 2 and 3. This was true regardless of the vaccine protocol used (CVI988/rHVT+SB-1; CVI988+rHVT+SB-1/None; rHVT+SB-1/CVI988; wherein the vaccine before the slash (/) was administered in ovo at embryonation day 18 and the vaccine after the slash was administered at day of age, subcutaneously). When only vaccines of serotypes 2 and 3 were used, protection against early challenge with vv+MDV was higher when vaccines were administered in ovo (rHVT+SB-1/None) than if vaccines were administered at hatch (None/rHVT+SB-1). Monitoring vaccine DNA load in feather pulp (FP) samples at 1 wk was used to monitor vaccination, and results showed that differences in vaccine replication exist among vaccines but such differences were not necessarily related to protection (r = 0.41, P > 0.05). Monitoring load of challenge MDV DNA in FP at 21 days was conducted, and results correlated (r = 0.85, P < 0.05) with the percentage of chickens with MD lesions at the termination of the study, confirming that early diagnosis is a very powerful tool with which to evaluate protection. © 2015 American Association of Avian Pathologists. Source

Discover hidden collaborations