No abstract

Copy number variation (CNV) is considered an important genetic variation, contributing to many economically important traits in the chicken. Although CNVs can be detected using a comparative genomic hybridization array, the high-density SNP array has provided an alternative way to identify CNVs in the chicken. In the current study, a chicken 60K SNP BeadChip was used to identify CNVs in two distinct chicken genetic lines (White Leghorn and dwarf) using the PENNCNV program. A total of 209 CNV regions were identified, distributing on chromosomes 1-22 and 24-28 and encompassing 13.55 Mb (1.42%) of chicken autosomal genome area. Three of seven selected CNVs (73.2% individuals) were completely validated by quantitative PCR. To our knowledge, this is the first report in the chicken identifying CNVs using a SNP array. Identification of 190 new identified CNVs illustrates the feasibility of the chicken 60K SNP BeadChip to detect CNVs in the chicken, which lays a solid foundation for future analyses of associations of CNVs with economically important phenotypes in chickens.

Currently, substitutions for antibiotic growth promoters in animals are attracting interest. This study investigated the effects of pig antibacterial peptides (PABP) on growth performance and small intestine mucosal immune responses in broilers. Three hundred 1-d-old Arbor Acre male broiler chickens were randomly allocated to 5 groups with 60 birds per group. The groups were control group; PABP administered in drinking water at 20 and 30 mg/L of water; or PABP supplemented in feed at 150 and 200 mg/kg of diet. The birds were fed a corn-soybean based diet for 6 wk. Chickens were weighed weekly and killed after 42 d of feeding, and growth performance was measured. Samples of the duodenum and jejunum were collected. The villus height, mucosa thickness, alkaline phosphatase activity, and numbers of secreting IgA and goblet cells were evaluated. The PABP-treated groups had greater BW and average daily gain, greater height of villus and thickness of gut mucosa, greater activity of alkaline phosphatase, higher ratio of secreting IgA, and a greater number of goblet cells compared with the control group (P<0.05). In conclusion, PABP can improve the growth performance, increase the intestinal ability to absorb nutrients, and improve the mucosal immunity of the intestine.

Growth hormone-releasing hormone receptor (GHRHR) plays a critical role in growth hormone (GH) synthesis, release and regulation in animals. The objective of this study was to investigate variations of the chicken GHRHR gene and their associations with growth and reproduction traits in 768 Beijing You chickens. Results revealed three single nucleotide polymorphisms (SNPs) in the promoter region of the gene (g.-1654A>G, g.-1411A>G and g.-142T>C). Association analysis revealed that the novel SNP g.-1654A>G had significant effects on chicken body weight at 7, 9, 11, 13, 17 weeks of age and the age of first egg as well as egg number at 32, 36 and 40 weeks. Significant association was also observed between g.-1411A>G and g.-142T>C with EN24. Moreover, the age of first egg was distinctly related with g.-142T>C (P < 0.05). Although significant statistical difference was not detected in GHRHR mRNA levels among genotypes of the SNPs (P > 0.05), strong expression variations of the gene were found between the ages 17 and 20 weeks in the population (P < 0.05). These results suggest that the three SNPs in the GHRHR promoter could be used as potential genetic markers to improve the growth and reproductive traits in chickens.

To monitor possible contamination of edible vegetables by common pesticides, an analytical method using gas chromatography combined with ion trap spectrometry (GC-IT/MS) was developed to measure simultaneously up to 39 pesticide residues, belonging to organophosphors, organochlorines, pyrethroids or carbamates classes, left on four kinds of popular vegetables. The procedure entails addition of acetone, dichloromethane, and sodium chloride to a small amount of vegetable, then the mixture was shaken intensively and centrifuged for phase separation. An aliquot of the organic layer was cleanup using solid-phase extraction (SPE) cartridges filled with graphitized carbon black (GCB) in combination with acidic aluminum oxide. Gas chromatography with ion trap mass spectrometer was then used for qualitative and quantitative determination of the pesticides. The GCB combination with acidic aluminum oxide was found more suitable than florisil, aluminum oxide and silicon dioxide for sample cleanup with recoveries above 70% for most pesticides in removing the majority of co-extracted matrices. Variation coefficients of the repeatability typically smaller than 20% have been achieved for a wide range of the investigated pesticides. A set of critical instrument parameters for the GC-IT/MS Varian system in the MS mode was established. Based on optimization work conducted in this study, the 39 pesticides were separated successively with the limits of detection between 0.02 and 0.1 mg/kg.