Delgadorice5225

Birds were sampled (n = 6) at -48, 0, 4, 24, 48, 72, 96, 144, 192, 240, 288, and 336 h post-hatch. Jejunum and ileum were collected, cleaned of digesta, and snap-frozen in liquid nitrogen or fixed in paraformaldehyde. The relative mRNA levels of gut barrier- and TJ-related protein genes were measured by quantitative PCR and analyzed by 2-way ANOVA. In both tissues, changes (P less then 0.05) in gene expression pattern of gut barrier-related and TJ-related genes were detected due to delayed access to feed post-hatch and/or development. In general, expression of TJ-related genes was downregulated while mRNA levels of gut barrier-related genes were upregulated during development. Histological differences and changes in mucin staining due to age and treatment were observed. These results suggest that delayed access to feed post-hatch may affect TJ structure and/or function and therefore gut barrier function and overall health of the chicken small intestine.Adaptive genetic variations have direct influences on the fitness traits of the animal. The major histocompatibility complex B (MHC-B) region is responsible for adaptive and innate immune responses in chickens. In native Korean chicken breeds, no information on serologically defined B haplotypes is available. We investigated the MHC-B diversity in 5 restored lines of Korean native chicken and Ogye chicken breeds using a recently described MHC-B single-nucleotide polymorphism (SNP) panel and the MHC-linked LEI0258 variable number of tandem repeat marker. High SNP haplotype diversity was observed in Korean native chicken breeds with an average of 9.7 MHC-B SNP haplotypes per line. The total number of haplotypes ranged from 6 to 12 per line, and population-specific haplotypes ranged from 3 to 4. A total of 41 BSNP haplotypes, including 26 novel population-specific haplotypes and 15 common haplotypes, were reported over all populations. The 15 common haplotypes included 7 novel and 8 previously reported standard haplotypes. Selection and breeding evidence supports the observation of common haplotypes between the Korean native chicken and exotic breeds. this website Similarly, the LEI0258 marker showed allele variation, between 193 bp and 474 bp having 5 to 8 alleles per population. Some of these alleles (193, 249, 309, and 443 bp) were shared and more frequently observed. Comparison between SNP haplotypes and LEI0258 allele sizes for the same samples showed that some LEI0258 allele sizes correspond to more than one BSNP haplotype. The use of the MHC-B SNP panel greatly enhances the identification of MHC diversity compared with the sole use of the LEI0258 marker in native chicken populations.The behavior, growth and development, and production performance of poultry are affected by the light environment. The influence of light results from a combination of light sources, light intensity, light color, and the photoperiod regimen. With light-emitting diode (LED) lamps applied in poultry housing systems, specific light colors are desired for each time period for layer chickens. The objective of this study was to investigate the effects of a 2-phase mixed color lighting program (phase 1 blue-green, 1 D-13 wk; phase 2 yellow-orange, 14-20 wk) using LED lights on the blood parameters, skeletal development parameters, and sexual development parameters of caged layer chickens during their brooding and rearing periods. Fifty-two chickens were raised from 1 D to 20 wk of age in each of the 4 treatment groups with 3 replicates, with white (400-700 nm) light at phase 1 and phase 2 (WL treatment as the control); blue-green (435-565 nm) light at phase 1 followed by yellow-orange (565-630 nm) light at phase 2 (sitive effects on the immune performance, bone development, and production performance of caged layer chickens during their brooding and rearing periods.Studies indicate that the evaluation of animal welfare in birds may be carried out with the measurement of the stress-related hormone corticosterone in feathers. However a standardized procedure for corticosterone measurements in feathers is lacking, a validation needs to be carried out for each new species before implementation. The aim of the present study was to establish a valid method to measure corticosterone concentrations in feathers of laying hens in a precise and repeatable manner using an established and commercially available ELISA. Validation was performed with feather pools of tail and interscapular feathers of commercial Lohmann Brown laying hens. Assessment groups, consisting of 5 replicates, were created. All replicates of an assessment group were processed at the same time. Each replicate was run in 4 repetitions by ELISA. Intra-assay and interassay CV was 7.5 and 6.4%, respectively. The serial dilution showed linearity and parallelism. Examining the hormone extraction efficiency by using different methanol volumes resulted in no statistical differences (P > 0.05). Pulverized feathers showed higher corticosterone values than minced feathers (P > 0.05). Differences were shown between 2 feather types (tail vs. interscapular feathers; P 0.05). With the present study, a valid protocol, feasible for analyzing feather pools of laying hens, was developed. It may provide fundamentals for further investigations on corticosterone in feathers as a noninvasive indicator to evaluate aspects of animal welfare.Different strains of commercial laying hens have been molded by varying selection pressures, impacting their production, health, and behavior. Therefore, assumptions that all laying hen strains use the given resources within aviary systems similarly and maintain equal health and performance may be false. We investigated interactions among patterns of aviary resource use by 2 strains of white and 2 strains of brown laying hens (4 units per strain, 144 hens per unit) with daily egg production, location of egg laying, keel fractures, and footpad damage across the lay cycle. Hens' distribution among resources (litter, nest, wire floor, ledge, and perch) was recorded during light and dark periods at 28, 54, and 72 wk of age. Daily egg production and location were recorded, and 20% of hens per unit were randomly selected and assessed for keel bone damage, foot health, and plumage quality. Production and health risks associated with hens' resource use were assessed using multivariable regression. During the day, more brown hens occupied wire floors, while larger numbers of white hens were on perches and litter.