[Show abstract][Hide abstract] ABSTRACT: Coccidiosis is caused by parasites of the genus Eimeria , belonging to phylum Apicomplexa. EmTFP250 is a high molecular mass, asexual stage antigen from Eimeria maxima (EM) strongly associated with maternal immunity in newly hatched chickens. Cloning and sequence analysis predict the antigen to be a novel member of the Thrombospondin-Related Adhesive Protein (TRAP) family. Three novel attenuated Salmonella enteritidis strains (ΔSE) expressing TRAP oligopeptides in association with a potential immune-enhancing CD 154 sequence, on the outer membrane protein lamB, were developed. Broiler chicks were grouped based on treatment and 10<SUP>8</SUP> cfu/chick of vectors expressing one of three sequences, or vehicle alone, was orally administered to each group. At 21 d of age, all groups were challenged with 10<SUP>4</SUP> sporulated oocysts/chick orally. Mortality at 5d post-challenge was markedly different (p<0.05) in chickens vaccinated with TRAP Upstream (US). To further evaluate the efficacy of TRAP US as a potential vaccine candidate, a similar study was conducted. Broilers were orally vaccinated with 10<SUP>8</SUP> cfu/chick vehicle with TRAP US and CD 154 or sham vaccinated with saline. Coccidia challenge was performed with 10<SUP>5 </SUP>sporulated oocysts/chick at 22 d of age. Immunized chickens showed remarkable improvement in weight gain (p<0.05) and had reduced mortality (p = 0.055) when compared to non-immunized controls. These two studies underscore the potential of EmTFP250 as a potential candidate for a recombinant vaccine targeting coccidiosis in chickens.
Full-text · Article · Nov 2010 · International Journal of Poultry Science
[Show abstract][Hide abstract] ABSTRACT: Beak trimming is necessary in commercial broiler breeders to prevent or decrease trauma as they mature. Two common beak-trimming methods were evaluated by early performance comparison with nontrimmed chicks (NBT). The robotic electrocautery device (ECD) trims and cauterizes the beak tip. The robotic infrared beak-trimming device (IBT) applies an infrared light beam to destroy the live basal tissue while leaving the hard corneum intact for the first approximately 10 d. In 2 experiments, day-of-hatch Ross 708 by-product chicks were obtained from a local hatchery, where 1/3 of the chicks were trimmed using IBT. All chicks were then transported to another hatchery where 1/3 were trimmed using ECD and 1/3 were NBT. Personnel at each hatchery were highly experienced and skilled with their respective technique. All chicks were then transported to University of Arkansas facilities. Before placement in each experiment, chicks were individually neck-tagged and weighed, and in experiment 1, beaks were measured using a digital caliper. A small but significant transient reduction in BW gain was observed at 14 d due to ECD as compared with NBT controls, although ECD was not different than IBT in experiment 1. In experiment 2, IBT birds were significantly heavier at 11 d by 7.8 and 8.7 g than the NBT or ECD, respectively. However, at d 21 and 42, no significant differences in BW or BW gain were observed. When beak trimming was performed on day of hatch by skilled and experienced personnel, little measurable effect on early performance was observed during the first 6 wk of life. Decreased broiler performance is generally considered a sensitive indication of physical or psychogenic stress. Given the marked reduction in beak-inflicted trauma with beak trimming birds as they reach sexual maturity, these results suggest that when properly performed, neither of these beak-trimming methods causes sufficient physical or psychogenic stress to markedly affect early growth rate.