Oviduct Fluke (Prosthogonimus macrorchis) Found Inside a Chicken Egg in North Carolina.

A video received by faculty at North Carolina State University's Prestage Department of Poultry Science revealed a live parasite inside a chicken egg. The parasite was identified as an oviduct fluke (Prosthogonimus macrorchis), a trematode with a three-host life cycle: the primary host, a galliform bird, then an aquatic snail, and finally a dragonfly larva or adult consumed by the infected bird. The egg was from a "backyard flock" with access to a watercourse. No other instances of this parasite were seen in eggs from the flock. The presence of this parasite inside an egg suggests that the worms had migrated above the shell gland in the oviduct to be incorporated inside the egg. Currently, the occurrence of an oviduct fluke inside an egg in the United States is rare. Such parasites are not found in eggs from caged layers because those birds do not have access to watercourses. This case reinforces the view that parasites requiring intermediate hosts may become more common in birds reared under free-range conditions.

A novel, simplified technique to amplify Eimeria (Coccidia: Apicomplexa) DNA from oocysts.

A new method to amplify coccidia DNA by polymerase chain reaction (PCR) was developed by placing freeze-thawed oocysts in Ready-to-Go PCR bead tubes and using a 5-min initial heat denaturation step. Positive PCR reactions were found in 3 of 3 samples containing 20 or 50 oocysts; when ≤5 oocysts were used, 1 of 3 samples was positive. This technique shows potential for effectively and efficiently detecting and identifying oocysts from soil, feces, and other matter.

Blackhead disease: reduced sensitivity of Histomonas meleagridis to nitarsone in vitro and in vivo.

Histomonas meleagridis, a flagellated protozoan parasite, is the causative agent of blackhead disease or histomoniasis in gallinaceous birds. Currently nitarsone (4-nitrophenylarsonic acid) is the only approved preventative drug available in the United States against blackhead disease. Initially we tested the sensitivity of three different isolates of H. meleagridis collected from outbreaks in North Carolina (strain MNC), Michigan (strain ZM), and Georgia (strain BG) to nitarsone using in vitro culture conditions. Strain ZM and strain BG at 100 and 400 ppm showed reduced growth in comparison to their respective control groups. However, there was no inhibition of growth in strain MNC treated with nitarsone at 100 ppm, while reduced growth was seen at 400 ppm. To test the resistance of strain MNC to nitarsone in vivo, turkey poults fed a nitarsone or a control diet were inoculated cloacally with H. meleagridis. The nitarsone-treated group of birds did not show any significant difference compared to that of infected control group when measuring weight gain and liver and cecal lesions scores. Histomonas meleagridis were reisolated from the nitarsone-fed turkeys and subjected to the in vitro assay. Regenerated H. meleagridis maintain their resistance to nitarsone at 100 ppm. This study demonstrates that strain MNC has acquired partial resistance to nitarsone.

No evidence of temperature-dependent sex determination or sex-biased embryo mortality in the chicken.

Skewing the sex ratio at hatch in commercial poultry would be economically beneficial to the poultry industry. The existence of temperature-dependent sex determination is uncertain in birds. This experiment investigated if incubation temperatures skew sex ratios of commercial broilers. Three incubators were each set at a hot (38.3°C), standard (37.5°C), or cool (36.7°C) single-stage incubation temperature one time over 3 trials to eliminate incubator effect as a Latin square design. Sex ratios of hatched chicks and dead embryos were monitored. In one trial, embryo weights were evaluated. The percentages of male hatched chicks did not differ based on incubation temperature (P = 0.4486; 49.5% in the hot treatment, 51.4% at standard temperature, and 49.8% in the cool treatment). The percent hatch of eggs set was lower in the hot treatment (83.6%) than the standard (93.5%) and cool (91.6%) treatments (P < 0.0001) with greater late embryonic mortality in the hot treatment (P < 0.0001); however, the sex ratio of dead embryos did not differ among treatments (P = 0.9863). Pooled data of embryo mortality found no sex-biased embryo mortality with a female/male sex ratio of 1.22:1 (χ(2) = 1.27; P = 0.2596). Embryos from the hot treatment were heavier than those from the standard treatment by d 14 of incubation and were heavier than the embryos from the cool treatment by d 9 of incubation (P < 0.0001). These data indicate that incubation temperature affects embryonic mortality and embryonic growth rate, but it does not affect the sex ratio of broiler chickens. Additionally, no evidence was found for sex-biased embryo mortality in commercial broilers even at the incubation temperatures of this study.

Amino acid digestibility and metabolizable energy of genetically selected soybean products.

To determine the ME and amino acid digestibility of 5 soybean meal (SBM) samples, a precision-fed rooster assay and a chick assay were conducted. The 5 samples were cold-pressed (extruded) soybean meals or solvent-extracted (defatted) soybean meal. Of the cold-pressed varieties (unheated), there was an ultra-low trypsin SBM, a low-trypsin SBM, and a heated and unheated commodity SBM. The solvent-extracted SBM was a heated commodity blend. The TME and AME values were compared between each category: cold-pressed and defatted, as well as between the 2 assays. Semipurified diets containing dextrose as the main energy source were formulated to meet the bird's nutrient requirements, with each diet containing a different SBM product. The TME rooster assay was a precision-fed rooster assay in which 5 birds per diet were fasted for 24 h, crop intubated with 35 g of the test diet containing 46.58% cold-pressed or defatted SBM, and excreta was then collected for 48 h. The total aromatic amino acids rooster assay followed the same protocol, but cecectomized birds were used. For the chick assay, 480 one-day-old chicks were fed a standard corn-SBM starter diet until 17 d of age, and on d 18, the chicks were allowed ad libitum access to the SB-dextrose diets. Excreta were collected on d 22, dried, ground, and analyzed for gross energy and CP to determine ME. The SBM samples that were genetically selected to have lower trypsin inhibitor levels and higher protein had higher ME values and increased amino acid digestibility than the commodity cold-pressed SBM samples. Genetic selection of soybeans for certain traits can have positive effects on the ME value and amino acid digestibility for roosters and chicks.

A genomic analysis of Histomonas meleagridis through sequencing of a cDNA library.

Histomonas meleagridis, a flagellated protozoan of the Order Trichomonadida, is the causative agent of blackhead disease in gallinaceous birds. Few genes have been identified in this organism; thus, little is known regarding the molecular basis for its metabolism, virulence, and antigenicity. To identify new genes, a cDNA library derived from a lab strain of H. meleagridis was sequenced and annotated. Data obtained from these experiments identified 3,425 H. meleagridis genes. Analysis of the data allowed the identification of 81 genes coding for putative hydrogenosomal proteins and was used to determine the codon usage frequency. Sequence information also identified bacteria that are cultured with H. meleagridis. Future analysis of these data should provide valuable molecular insights into H. meleagridis and provide the platform for molecular studies aimed at understanding the pathogenesis of blackhead disease.

An outbreak of blackhead disease (Histomonas meleagridis) in farm-reared bobwhite quail (Colinus virginianus).

An outbreak of blackhead disease (Histomonas meleagridis) in farm-reared flock of 13,500 bobwhite quail (Colinus virginianus) resulted in mortality totaling approximately 1500 in 4 wk. Necropsy of 56 dead birds at midoutbreak (from a total that day of 131) revealed that 55 had severe cecal lesions typical of blackhead, and only 3 had visible lesions in the liver. Necropsy of apparently healthy birds failed to detect any signs of infection. Presence of H. meleagridis in affected ceca was proved by culture in vitro and PCR tests.

Establishment of culture conditions for survival of Histomonas meleagridis in transit.

Fresh ceca samples from turkeys in North Carolina infected with Histomonas meleagridis were collected at necropsy, inoculated into warmed Dwyers medium, and sent by overnight courier to our laboratory at The University of Georgia. Further incubation at 40 C yielded positive cultures from all four samples. PCR and DNA sequencing confirmed the presence of H. meleagridis. To further establish conditions for survival in transit, we infected turkeys with H. meleagridis, euthanatized the birds 10 days postinfection, and allowed carcasses to incubate at room temperature for either 2 or 24 hr. After incubation, samples of cecal contents (0.5 g) were placed in Dwyers medium and held at 4, 25, or 30 C for 6, 18, 24, 48, 72, 96, or 120 hr, simulating holding conditions during transit. Samples were placed in a 40 C incubator at the specified times and examined daily for histomonad growth by light microscopy. Positive histomonad growth was detected from cecal samples obtained from the 2-hr incubated carcass and from cultures held at 30 C for 6, 18, 24, 48, and 72 hr. No growth was seen from cultures held at 25 or 4 C or at any temperature from the carcass allowed to incubate for 24 hr at room temperature. These results suggest that positive isolation can be made from field samples, provided that material is collected at warm temperatures and transported rapidly to the laboratory.

Low-dose immunization of northern bobwhites (Colinus virginianus) with Eimeria lettyae provides protection against a high-dose challenge.

To determine whether northern bobwhite quail (Colinus virginianus) could be immunized against Eimeria lettyae by a low-dose inoculation of oocysts, we inoculated 30 birds each with either 100 or 1000 oocysts at 2 days of age (given orally by pipette). Four weeks after immunization, the immunized birds and unimmunized controls were challenged with 1 x 10(6) E. lettyae oocysts. Eight days after challenge, birds were killed and weighed, and their intestines examined for gross lesions. Effectiveness of the immunization was measured by analyzing weight gain, intestinal lesions, severity of diarrhea, feed conversion ratio, and oocyst production. After challenge, birds immunized with 100 or 1000 oocysts gained an average of 33.3 g and 28.9 g, respectively, whereas unimmunized challenged birds gained an average of 11.5 g. Immunized quail produced approximately 99.7% fewer oocysts, had minimal gross intestinal and cecal lesions, had minimal diarrhea, and had a 50% lower feed conversion ratio compared to unimmunized challenged controls. These findings indicate that vaccination is a viable option for controlling coccidiosis in quail and that further research into vaccination is warranted.

Bonus, a Drosophila TIF1 homolog, is a chromatin-associated protein that acts as a modifier of position-effect variegation.

Bonus, a Drosophila TIF1 homolog, is a nuclear receptor cofactor required for viability, molting, and numerous morphological events. Here we establish a role for Bonus in the modulation of chromatin structure. We show that weak loss-of-function alleles of bonus have a more deleterious effect on males than on females. This male-enhanced lethality is not due to a defect in dosage compensation or somatic sex differentiation, but to the presence of the Y chromosome. Additionally, we show that bonus acts as both an enhancer and a suppressor of position-effect variegation. By immunostaining, we demonstrate that Bonus is associated with both interphase and prophase chromosomes and through chromatin immunoprecipitation show that two of these sites correspond to the histone gene cluster and the Stellate locus.

Synaptic vesicle size and number are regulated by a clathrin adaptor protein required for endocytosis.

Clathrin-mediated endocytosis is thought to involve the activity of the clathrin adaptor protein AP180. However, the role of this protein in endocytosis in vivo remains unknown. Here, we show that a mutation that eliminates an AP180 homolog (LAP) in Drosophila severely impairs the efficiency of synaptic vesicle endocytosis and alters the normal localization of clathrin in nerve terminals. Most importantly, the size of both synaptic vesicles and quanta is significantly increased in lap mutants. These results provide novel insights into the molecular mechanism of endocytosis and reveal a role for AP180 in regulating vesicle size through a clathrin-dependent reassembly process.