RNA-Seq analysis reveals expression regulatory divergence of W-linked genes between two contrasting chicken breeds

The regulation of gene expression is a complex process involving organism function and phenotypic diversity, and is caused by cis- and trans- regulation. While prior studies identified the regulatory pattern of the autosome rewiring in hybrids, the role of gene regulation in W sex chromosomes is not clear due to their degradation and sex-limit expression. Here, we developed reciprocal crosses of two chicken breeds, White Leghorn and Cornish Game, which exhibited broad differences of gender-related traits, and assessed the expression of the genes on W chromosome to disentangle the contribution of cis- and trans-factors to expression divergence. We found that there was not appear to be an association between female fecundity and W chromosome gene expression, that 44% of expressed genes had divergent expression between breeds in both tissues, with only 17% of them showing greater expression in White Leghorn. We observed that the proportion of trans-acting genes in W chromosome was higher than cis-regulatory divergence. There were most parental divergence expression genes in muscle, also more heterosis compared with other two tissues. A strong dominant impact of Cornish alleles in brain, while obvious crosses-specific regulatory patterns appeared in liver. Taken together, this work describes the regulatory divergence of W-linked genes between two contrasting breeds and indicates sex chromosomes have a unique regulation and expression mechanism.

Subchronic Acephate Exposure Induces Immunotoxicity in White Leghorn Cockerels

We investigated the subchronic immunotoxicity of the phosphoramidothioate organophosphorous insecticide, acephate in white leghorn cockerels (WLH). The cockerels were divided into five groups; C1 (plain control), C2 (vehicle control), T1, T2, and T3 which received acephate suspended groundnut oil for 60 days at doses of 21.3, 28.4 and 42.6 mgkg−1respectively. The live body weight gain, absolute and relative weights of the spleen, thymus, and bursa of Fabricius, hemoglobin (Hb), total erythrocyte counts (TEC), packed cell volume (PCV) and lymphocytes were significantly decreased. However, monocytes, eosinophils, heterophils, and basophils were significantly increased. Total protein, albumin and albumin to globin ratio, the antibody response to RD-F and delayed-type hypersensitivity response to DNCB dye or PHA-P, erythrocyte and brain Acetylcholinesterase activity was also significantly reduced in T2 and T3. At 40 and 60 days of acephate exposure, nitrate and nitric oxide production by RD-F and mitogen Con A stimulated peripheral blood and splenic lymphocytes, as well as lymphocyte proliferation in response to antigen RD-F and mitogen Con A stimulation, were significantly decreased in groups T2 and T3. Furthermore, dose-dependent increases in the frequency of micronuclei formation, varying intensity serum protein bands with different protein fractions (14.85KDa), and splenic DNA laddering (180 bp) were observed in groups T2 and T3. Histopathologically, the spleen and bursa showed morphological changes and mild lymphocyte depletion. In conclusion, low-level acephate exposure may affect acetylcholinesterase, lymphocytes, and immune responses in cockerels. As a result, it should be considered when assessing immunotoxicity and the risk to human and animal health.

Bioactivity of Cooked Standard and Enriched Whole Eggs from White Leghorn and Rhode Island Red in Exhibiting In-Vitro Antioxidant and ACE-Inhibitory Effects

Hen breed, diet enrichment, cooking methods, and gastrointestinal (GI) digestion modulates the bioaccessibility of the bioactive compounds in eggs, but their synergistic role in modulating bioactivity is still unclear. The present study evaluates the effect of hen breed, diet enrichment, and GI digestion on the cooked whole egg-derived peptides in-vitro antioxidant and antihypertensive activities. Standard and enriched whole eggs from White Leghorn (WLH) and Rhode Island Red (RIR) hens were boiled or fried and subjected to GI digestion. Antioxidant activity was measured through oxygen radical absorbance capacity (ORAC) and gastrointestinal epithelial cell-based assays, and the antihypertensive capacity by in-vitro Angiotensin-I Converting Enzyme (ACE) inhibition assay. WLH fried standard egg hydrolysate showed a high ORAC antioxidant activity but failed to show any significant antioxidant effect in the cell-based assay. No significant differences were observed in the antihypertensive activity, although enriched samples tended to have a higher ACE-inhibitory capacity. The peptide profile explained the antioxidant capacities based on antioxidant structural requirements from different peptide fractions, while previously reported antihypertensive peptides were found in all samples. The study validates the importance of physiologically relevant models and requires future studies to confirm mechanisms that yield bioactive compounds in whole egg hydrolysates.

Cuticle deposition duration in the uterus is correlated with eggshell cuticle quality in White Leghorn laying hens

The cuticle formed in the uterus is the outermost layer as the first defense line of eggshell against microbial invasions in most avian species, and analyzing its genetic regulation and influencing factors are of great importance to egg biosecurity in poultry production worldwide. The current study compared the uterine transcriptome and proteome of laying hens producing eggs with good and poor cuticle quality (GC and PC, the top and tail of the cuticle quality distribution), and identified several genes involved with eggshell cuticle quality (ESCQ). Overall, transcriptomic analysis identified 53 differentially expressed genes (DEGs) between PC versus GC group hens, among which 25 were up-regulated and 28 were down-regulated. No differences were found in the uterine proteome. Several DEGs, including PTGDS, PLCG2, ADM and PRLR related to uterine functions and reproductive hormones, were validated by qPCR analysis. Egg quality measurements between GC and PC hens showed GC hens had longer laying interval between two consecutive ovipositions (25.64 ± 1.23 vs 24.94 ± 1.12 h) and thicker eggshell thickness (352.01 ± 23.04 vs 316.20 ± 30.58 μm) (P < 0.05). Apart from eggshell traits, other egg quality traits didn’t differ. The result demonstrated eggshell and cuticle deposition duration in the uterus is one of the major factors affecting ESCQ in laying hens. PTGDS, PLCG2, ADM and PRLR genes were discovered and might play crucial roles in cuticle deposition by regulating the uterine muscular activities and secretion function. The findings in the present study provide new insights into the genetic regulation of cuticle deposition in laying hens and establish a foundation for further investigations.

Biology of Attagenus fasciatus Thunberg (Coleoptera: Dermestidae) on four different diets of animal origin

Biology of dermestid beetle, Attagenus fasciatus was studied on four different diets of animal origin included dried silkworm pupae and moths of Bombyx mori, feathers of white leghorn and on an equal mixture of fur of goat and sheep under laboratory conditions, to know the dietary effect on the developmental process. The mean incubation period was 12-16 days. There were 10-12 larval instars. The life-cycle on four different diets of animal origin varied. On dried silkworm pupae, total larval period ranged from 243 to 298 days and total life-cycle 267-326 days; on dried silk moths, total larval period was 251-307 and total life-cycle 272-330 days; on feathers of white leghorn, total larval period was 264-329 and total life-cycle was 288-355 days, and on an equal mixture of fur of goat and sheep, total larval period was 273-317 and total life-cycle was 297-343 days.

PSVI-14 Characteristic of hybrid chicken derived from crossing of Ogye and white leghorn

Ogye, an indigenous Korean chicken breed has entirely black external features and internal organs. White Leghron, an transboundary breed has white color features as opposed to Ogye. We make crossbreed (Ogye x White Leghorn) to investigate how the phenotype appeared in F1. In F0, 5 females and 1 male were selected for each parental type; 1) Ogye(♂) x White leghorn(♀), 2) White leghron(♂) x Ogye(♀). We A total of 321 individuals of F1 were made through artificial insemination. We measured body weights at birth, 8 weeks, 16 weeks, 24 weeks, and 32 weeks of age. In 1) type females, the average of body weight at each period was 39.04±0.32, 613.18±6.86, 1149.37±7.76, 1463.97±13.25, 1718.02±14.83 respectively. In 2 type females, that was 30.57±0.21, 543.19±7.54, 1069.63±12.92, 1410.06±10.80, 1527.53±13.73. The P-value values for each period were less than 0.05. In 1) type males, the average of body weight at each period was 39.18±0.34, 744.70±7.84, 1579.39±15.76, 2014.63±19.15, 2310.89±20.58. In 2 type females, that was 30.71±0.24, 683.75±9.51, 1419.79±15.76, 1800.00±18.88, 2064.79±19.68. The P-value values for each period were also less than 0.05. In the case of feather color, it was generally white, but black spots appeared only in females produced in type 1). Comb and beak color was generally also red, but black appeared only in in females produced in type 1). From these results, it can be estimated that paternal factors such as weight and appearance are greatly affected, and we plan to investigate the genetic patterns of each trait through F2 construction in the future.

PCR-RFLP Analysis of Single Nucleotide Polymorphism (SNP) C-2402T at the Promoter Region of Prolactin Gene and its Association with Positively Correlated Production Traits in White Leghorn Chicken

Background: The avian prolactin gene is highly conserved, located on chromosome number 2 and most sequence polymorphisms occurs in the 5’ flanking region, 3’ flanking region, and the coding region of signal peptide. The present study was aimed at the identification of SNP C-2402T of prolactin gene and its association with production traits in White Leghorn chicken. Methods: A total of 200 birds of White Leghorn were selected from All India Co-ordinated Research Project on Poultry improvement (AICRP) farm, Mannuthy. Genomic DNA was isolated from venous blood. Polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) analysis was done to identify the SNP C-2402T of prolactin gene. Result: All the birds were observed with the same genotype CC and the frequency of the C allele was one.

​Boron Supplementation to Calcium Inadequate Diet Influences Mineral Content of Serum, Tissue and Antioxidant Status in White Leghorn Layers

Background: Boron (B), a novel micronutrient is known to influence utilization of macrominerals. Present study was conducted in layer birds to study the effect of B supplementation to inadequate calcium (Ca) diet on mineral content in serum, tissue and antioxidant status. Methods: A total of 80 commrcial White Leghorn layers, 25 weeks old with a uniform body weight were randomly assigned to one of the 4 groups of 20 hens in each dietary group viz., Normal calcium (NC), inadequate/low calcium (LC), Normal calcium with 40 ppm B (NCB) and inadequate/low calcium with 40 ppm B (LCB). Dietary level of calcium was maintained at 100 and 90% of the requirement and sodium borate was used as B source. At the end of feeding trial, blood and tissue samples were collected for estimating mineral and biochemical parameters. Result: Boron supplementation did not significantly alter the serum mineral content, serum alkaline phosphatase and total antioxidant activity but significantly (P less than 0.025) increased the superoxide dismutase activity in layers fed inadequate Ca diet. Boron supplementation to both diets significantly (P less than 0.03) increased phosphorus (P) content in bone and muscle, and magnesium (Mg) content in muscle (P less than 0.019). Boron supplementation to Ca inadequate diet significantly (P less than 0.006) enhanced the P and Mg content in liver. Content of B was significantly (P less than 0.01) higher in serum, bone and liver of hens supplemented 40 ppm of B. Implication of this study is amelioration of abiotic stress due to inadequate Ca intake with B supplementation. It is concluded that 40 ppm B supplementation positively influenced the Ca, P and Mg utilization and serum SOD activity.