Population genomics reveals that a missense mutation in EDNRB2 contributes to white plumage color in pigeons.

Plumage color is an important economic trait for breed feature identification and consumer's requirements in pigeons. The domestic pigeon has multiple types of plumage color, thereby providing a unique opportunity to identify the genetic basis of plumage coloration. White feather color is common for meat and medicinal use. To investigate the genetic variation associated with white plumage color in pigeons, we use genome resequencing and population genomics to identify the genomic regions with strong selective signature between pigeons with brown and white plumage color. Meanwhile, we obtained some candidate genes with melanin or melanosome biosynthesis in selected regions. Finally, we identified a missense mutation p.E256K in the EDNRB2 completely associated with white plumage color. These findings provide a basis for genetic variation in pigeons with plumage color phenotype.

Research Note: Effect of age on hematological parameter and reference intervals for commercial Lohmann silver layer.

Hematological parameters play a key role in assessing the disease states and physiological status of birds, however the reliable information of hematological reference values for Lohmann silver in the pre- and post-laying periods is limited. Thus, the aim of this study was to research the effect of age on hematological parameters and provide reliable reference intervals for commercial Lohmann silver layer. Blood samples were obtained from 231 laying hens at different ages (5-37 wk) with 4-wk sampling intervals. A total of 12 hematological parameters including leucocytes (WBC, 109/L), red blood cell (RBC,1012/L), hemoglobin (HGB, g/L), hematocrit (HCT,%), mean corpuscular volume (MCV, fL), mean corpuscular hemoglobin (MCH, pg), mean corpuscular hemoglobin concentration (MCHC, g/L), red cell distribution width (RDW,%), platelet count (PLT,109/L), mean platelet volume (MPV, fL), platelet volume distribution width (PDW), plateletcrit (PCT, fL) were determined with a reference value advisor. One-ANOVA and Tukey test were utilized to test for significant differences of each parameter between ages. Our findings showed that these parameters were significantly affected by age, except for HCT in the pre-laying period. And reference intervals for all parameters except MCH, MCHC, MCV, MPV, and PDW in the pre-laying period were higher than that in the post-laying period. The results of this study may serve as indispensable information when diagnosing the health of Lohmann silver layer.

Effect of housing system and age on products and bone properties of Taihang chickens.

The aim of this study was to compare egg quality, carcass, meat characteristics, and bone properties of Taihang chickens in 2 different housing systems at various ages. A total of 168 birds were selected and randomly allocated to 2 groups at 23 wks and raised in conventional cage (CC) or flattening on floor (FF) housing system, respectively. FF hens' egg weight, albumen height, and Haugh unit were higher (P < 0.05), and yolk weight was lower (P < 0.001) than those of the CC hens. Egg quantity of FF hens was higher than that of the CC hens (P < 0.01). The FF hens' weight (P < 0.05) and breast meat percent (P < 0.01) were higher than those of the CC hens. The highest live body and carcass weight were observed at 57 wk (both P < 0.01), whereas the highest semieviscerated percentage (P < 0.01) and meat weight of breast and thigh (P < 0.05) were shown at 49 wk. The highest eviscerated percentage and thigh meat were displayed at 41 and 32 wk, respectively (P < 0.01). For meat color, the lightness of both breast and thigh meat in the FF group was significantly reduced compared with those of the CC group (P < 0.01 and P < 0.05). FF hens' humerus weight and breaking strength (both P < 0.01) and tibia breaking strength (P < 0.05) were significantly higher than those of the CC hens. Femur breaking strength was significantly affected by hens' age (P < 0.01). Egg weight, albumen height, Haugh unit, yolk color (all P < 0.01), pH of thigh meat, semieviscerated, and eviscerated weight (all P < 0.05) were influenced by the interaction of housing system and age, whereas no change in moisture loss rate, meat color, shearing force, and bone quality was found (P > 0.05). In summary, in the 2 housing systems, hens' age and their interaction could affect slaughter performance, quality of egg, meat, and bone of Taihang chickens. In addition, the results of the present study support a theoretical basis for the development and utilization of Taihang chickens in accordance with the FF system.

Evolution and differentiation of the prion protein gene (PRNP) among species.

A total of 937 prion protein gene (PRNP) sequences belonging to 83 species in 56 genera of 26 families were analyzed in order to investigate its evolution and differentiation among species. The length of PRNP coding sequence for all species analyzed varied from 567 to 825 bp, which was mainly because of insertion or deletion in the repeat region within and among the species. TGA and TAG are the main stop codons in the PRNP gene. Bos taurus had the smallest variation in terms of average number of nucleotide differences (0.811), nucleotide diversity (0.0011), and nonsynonymous nucleotide diversity (0.0002) among all the ruminants. The reconstructed phylogenetic tree of PRNP of families and species was basically consistent with the taxonomy of National Center for Biotechnology Information except for Felidae (Felis catus), which was initially clustered with Moschidae rather than Mustelidae or Canidae.