[Show abstract][Hide abstract] ABSTRACT: Artificial illumination is widely used in modern poultry houses and different wavelengths of light affect poultry production and behaviour. In this study, we measure mRNA and protein abundance of estrogen receptors (ERs) and progesterone receptors (PRs) in order to investigate the effect of monochromatic light on egg production traits and gonadal hormone function in chicken ovarian follicles. Five hundred and fifty-two 19-wk-old laying hens were exposed to three monochromatic lights: red (RL; 660 nm), green (GL; 560 nm), blue (BL; 480 nm) and control cool white (400-760 nm) light with an LED (light-emitting diode). There were 4 identical light-controlled rooms (n = 138) each containing 3 replicate pens (46 birds per pen). Water was supplied ad libitum and daily rations were determined according to the nutrient suggestions for poultry. Results showed that under BL conditions there was an increase in the total number of eggs at 300 days of age and egg-laying rate during the peak laying period. The BL and GL extended the duration of the peak laying period. Plasma melatonin was lowest in birds reared under BL. Plasma estradiol was elevated in the GL-exposed laying hens, and GL and BL increased progesterone at 28 wk of age. In the granulosa layers of the fifth largest preovulatory follicle (F5), the third largest preovulatory follicle (F3) and the largest preovulatory follicle (F1), ERα mRNA was increased by BL and GL. Treatment with BL increased ERβ mRNA in granulosa layers of F5, F3 and F1, while GL increased ERβ mRNA in F5 and F3. There was a corresponding increase in abundance of the proteins in the granulosa layers of F5, with an increase in PR-B, generated via an alternative splice site, relative to PR-A. Treatment with BL also increased expression of PR mRNA in all of the granulosa layers of follicles, while treatment with GL increased expression of PR mRNA in granulosa layers of SYF(small yellow follicle), F5 and F1. These results indicate that blue and green monochromatic lights promote egg production traits via stimulating gonadal hormone secretion and up-regulating expression of ERs and PRs. Changes in PR-B protein suggest that this form of the progesterone receptor is predominant for progesterone action in the granulosa layers of preovulatory follicles in chickens during light stimulation.
[Show abstract][Hide abstract] ABSTRACT: Lysine is typically the second-limiting amino acid in poultry diets. The objective of this study was to evaluate the effects of dietary lysine concentration on carcass and meat quality traits, and serum parameters in two lines – SD02 and SD03 – which originated from a Chinese local breed, the Erlang Mountainous chicken. Live body weight, carcass traits, meat quality traits (myofibre diameter and density), and serum metabolic markers were measured in high and low dietary lysine groups (HL and LL, respectively) at the end of the starter (1-28 days), grower (29-49 days) and finisher (50-70 days) periods. The results showed that mortality, live weight (LW), myofibre diameter of leg muscle (LFDM) and serum cholesterol (CHO) were greater in HL than LL (P<0.05). The chickens from HL had reduced subcutaneous fat thickness and heart weight than LL (P<0.05). The chickens from line SD02 had greater leg muscle weight, myofibre diameter in breast, and LFDM than line SD03 (P<0.05). The chickens from line SD02 had more serum urea nitrogen and less total proteins than line SD03 (P<0.05). In conclusion, high lysine diets improved slaughter performance and muscle fibre diameter, and SD02 chickens had greater carcass yield and superior meat quality compared with chickens from line SD03.
Preview · Article · Aug 2015 · Italian Journal of Animal Science
[Show abstract][Hide abstract] ABSTRACT: Vertebrate β-defensins comprise an important family of antimicrobial peptides that protect organisms from a diverse spectrum of bacteria, viruses, fungi, and protozoan parasites. Previous studies have shown a marked variation in the number of β-defensins among species, but the underlying reason is unclear. To address this question, we performed comprehensive computational searches to study the intact β-defensin genes from 29 vertebrates. Phylogenetic analysis of the β-defensin genes in vertebrates identified frequent changes in the number of β-defensin genes and multiple species-specific gene gains and losses that have been occurring throughout the evolution of vertebrates. The number of intact β-defensin genes varied from 1 in the western clawed frog to 20 in cattle, with numerous expansions and contractions of the gene family throughout vertebrates, especially among tetrapods. The β-defensin gene number in a species is relevant to the ever-changing microbial challenges from the environment that they inhabit. Selection pressure analysis shows there exist three amino acid sites under significant positive selection. Protein structural characteristics analysis suggests that structural diversity determines the diverse functions of β-defensins. Our study provides a new perspective on the relationships among vertebrate β-defensin gene repertoires and different survival circumstances, which helps explain how β-defensins have evolved
Full-text · Article · Jun 2015 · Evolutionary bioinformatics online
[Show abstract][Hide abstract] ABSTRACT: Improved meat quality and greater muscle yield are highly sought after in high-quality chicken breeding programs. Past studies indicated that polymorphisms of the Perilipin gene (PLIN1) are highly associated with adiposity in mammals and are potential molecular markers for improving meat quality and carcass traits in chickens. In the present study, we screened single nucleotide polymorphisms (SNPs) in all exons of the PLIN1 gene with a direct sequencing method in six populations with different genetic backgrounds (total 240 individuals). We evaluated the association between the polymorphisms and carcass and meat quality traits. We identified three SNPs, located on the 5' flanking region and exon 1 of PLIN1 on chromosome 10 (rs315831750, rs313726543, and rs80724063, respectively). Eight main haplotypes were constructed based on these SNPs. We calculated the allelic and genotypic frequencies, and genetic diversity parameters of the three SNPs. The polymorphism information content (PIC) ranged from 0.2768 to 0.3750, which reflected an intermediate genetic diversity for all chickens. The CC, CT, and TT genotypes influenced the percentage of breast muscle (PBM), percentage of leg muscle (PLM) and percentage of abdominal fat at rs315831750 (p<0.05). Diplotypes (haplotype pairs) affected the percentage of eviscerated weight (PEW) and PBM (p<0.05). Compared with chickens carrying other diplotypes, H3H7 had the greatest PEW and H2H2 had the greatest PBM, and those with diplotype H7H7 had the smallest PEW and PBM. We conclude that PLIN1 gene polymorphisms may affect broiler carcass and breast muscle yields, and diplotypes H3H7 and H2H2 could be positive molecular markers to enhance PEW and PBM in chickens.
Preview · Article · Jun 2015 · Asian Australasian Journal of Animal Sciences
[Show abstract][Hide abstract] ABSTRACT: Abstract The problem of hypoxia adaptation in high altitudes is an unsolved brainteaser in the field of life sciences. As one of the best chicken breeds with adaptability to highland environment, the Tibetan chicken, is genetically different from lowland chicken breeds. In order to gain a better understanding of the mechanism of hypoxic adaptability in high altitude, in the present study, we focused on the MT-COI together with ATP-6 gene to explore the regulatory mechanisms for hypoxia adaptability in Tibet chicken. Here, we sequenced MT-COI of 29 Tibetan chickens and 30 Chinese domestic chickens and ATP-6 gene of 28 Tibetan chickens and 29 Chinese domestic chickens. In MT-COI gene, 9 single nucleotide polymorphisms (SNPs) were detected though none of these was a missense mutation, confirming the fact that MT-COI gene is a largely conservative sequence. In ATP-6 gene, 6 single nucleotide polymorphisms (SNPs) were detected and we found a missense mutation (m.9441G > A) in the ATP-6 gene of Tibetan chicken resulting in an amino acid substitution. Due to the critical role of ATP-6 gene in the proton translocation and energy metabolism, we speculated the possibility of this mutation playing an important role in easier energy conversion and metabolism in Tibetan chickens than Chinese domestic chickens so as to better adapt to the harsh environment of the high-altitude areas. The Median-joining profile also suggested that haplotype Ha2 has the ancestral position to the other haplotypes and has significant relationship with high-altitude adaptation in ATP-6 gene. Therefore, we considered that the polymorphism (m.9441G > A) in the ATP-6 gene may affect the specific functions of ATP-6 enzyme relating to high-altitude adaptation of Tibetan chicken and MT-COI gene is a largely conservative sequence.
Full-text · Article · Feb 2015 · Mitochondrial DNA
[Show abstract][Hide abstract] ABSTRACT: In this study, we quantified the expression of CRBP1 and CRBP3 in Roman layer (R) and Erlang mountainous chickens (SD02 and SD03), to discern the tissue, breed and age-related expression patterns in order to discover potential involvement in egg production and other related reproduction traits. Real-time quantitative PCR assays were developed for accurate measurement of CRBP1 and CRBP3 mRNA levels in different tissues from chickens at four ages (12, 20, 32 and 45 weeks). We found that the CRBP1 and CRBP3 were expressed in all six tissues examined in all three breeds of chicken at 32 weeks. CRBP1 mRNA levels in SD02 kidneys were slightly higher than those in SD03 and R at 12 weeks, whereas, at the other three time points, the expression levels of CRBP1 in SD03 were higher than those in SD02 and R. In addition, there was higher hepatic expression of CRBP3 mRNA in layers (R) compared to broilers (SD02 and SD03) at 20 and 32 weeks. An age-related expression pattern of CRBP1 gene was evident in liver (P < 0.01), but not in pituitary (P > 0.05). Overall, the expression level of CRBP1 gene in kidney, ovary and oviduct at the different ages had a "decline-rise-decline" trend in all three breeds. In contrast, in pituitary, hypothalamus, liver and kidney CRBP3 mRNA expression levels were significantly different at various ages (P < 0.05) and exhibited a "rise-decline-rise" pattern in all three breeds. Our results show that the expression of CRBP1 and CRBP3 in chicken tissues exhibit specific developmental changes and age-related patterns.
[Show abstract][Hide abstract] ABSTRACT: This experiment used 2 lines of chickens that have been selected 54 generations for either low (LWS) or high (HWS) 8-wk BW from the same founder population, sublines (HWR and LWR) in which selection was relaxed in generation 43 in the selected lines, and crosses (HL and LH) made from generation 54 of HWS and LWS. For 8-wk BW, the difference between lines LWS and HWS in generation 54 was approximately 10-fold, whereas for the relaxed contemporary lines they were approximately 7-fold. Three trials were designed to measure developmental, nutritional, and genetic aspects of blood glucose homeostasis during the first 2 wk posthatch. In trial 1, we measured BW, whole blood glucose (BG), and weights (relative to BW) of liver, pancreas, and yolk sac of chicks fed from day of hatch to d 15. In trial 2, we compared those traits in chicks feed-delayed 72 h posthatch and in chicks without feed delay. In trial 3, we evaluated the effect of a 16-h fast on BW and BG on d 3, 8, and 15. There were higher levels of BG in HWS than LWS, and males than females in the fed state. Delayed access to feed for 72 h after hatch was associated with a dramatic reduction in BG. Feeding triggered a compensatory response whereby LWS displayed greater BG but smaller pancreases (% BW; d 15), compared with the controls. There were maternal effects for BW in both fed and fasted states and the reciprocal crosses exhibited heterosis for BG in the fasted state. These results show that chickens selected for high or low BW differ in BG regulation during the early posthatch period.
[Show abstract][Hide abstract] ABSTRACT: The major histocompatibility complex (MHC) among chickens has been well established as being associated with disease resistance and pathogens infection, but the genetic differences in MHC between chickens susceptible to certain infections and those chickens that remain uninfected have not been sufficiently determined. In this study, we sought the genetic basis that may underlie differences in susceptibility to infection among chickens by challenging four groups of broilers with Marek's disease virus (MDV). Over the course of the experiment, lesions began to appear between 21 and 35 days post challenge (dpc), and commercial broilers were not necessarily better than indigenous chickens in terms of disease resistance. The four groups showed neutral resistance to MDV infection validated by challenge results and evolutionary analysis of exons 2 and 3 of the MHC class I region. Several variable sites in exon 2 and exon 3 were exclusively appeared in infected chickens. Exon 3 was likely more crucial than exon 2 in disease resistance. Our observations offered a support for a potential association between promiscuous pathogens and conspicuous genetic diversity in the MHC class I region.
No preview · Article · Nov 2013 · Infection, genetics and evolution: journal of molecular epidemiology and evolutionary genetics in infectious diseases
[Show abstract][Hide abstract] ABSTRACT: Fatty deposition in organism is an important factor which influences meat quality. Previously, Heart Fatty Acid-Binding Protein (H-FABP) gene was studied as a candidate gene which having effect on Intramuscular Fat content (IMF). In current study, we chose four SNPs loci (g.260T>C, g.675G>A, g.783C>T and g. 1198T>C) of H-FABP which have been proved to have distinct correlation with IMF as molecular markers to scan SNPs in a new breeding Chinese yellow-feather broiler population. Researchers allocated adaptive individuals into high-IMF group and low-IMF group according to the haplotypes which were constructed of genotypes at four SNP sites of each individual in F[generation and these haplotypes had been proved to be the preponderant or recessive haplotype. The core group was chose from the F[generation based on the traditional breeding method. And then, we detected the genotypes of the four loci by SNPs screening and analyzed the selection effect in F 2 generation which were obtained from mating and crossing within each group. Results indicated that the preponderance alleles were changed at Locus 1, 3 and 4 in the three groups of F 2 and there were no significant differences in IMF among the three groups (p>0.05). However, the IMF of the core group and the low fat group was higher than which of high fat group. The result of variance analysis showed that there were no significant difference in the effect of the different genotypes of the four SNPs on IMF (p>0.05). The four loci on the H-FABP gene in the research were not suitable as candidate markers to select IMF in this yellow-feather broiler strain.
No preview · Article · Oct 2012 · Journal of Animal and Veterinary Advances
[Show abstract][Hide abstract] ABSTRACT: The MyoD gene family has been proposed to profoundly modulate muscle development and carcass performance in farm animals. In this study, researchers examined Single Nucleotide Polymorphisms (SNPs) in the exons of the Myf5, Myf6 and MyoG genes using Polymerase Chain Reaction (PCR)-Single Strand Conformation Polymorphisms (SSCP) and DNA sequencing methods in 360 individuals from 6 commercial pure lines of Sichuan Daheng meat type quality chickens. About 2 SNPs (87T>C and 96C>T) in exon 1 of Myf5, 1 SNP (154T>C) in exon 1 of MyoG and no variation in Myf6 were detected. The 960>T SNP in Myf5 was a rare variant and was not analyzed further. The association analysis of genotypes with carcass traits revealed that the genotypes of SNP (87T>C) in Myf5 were significantly associated with Live Weight (LW), Carcass Weight (CW), Semi-Eviscerated Weight (SEW) and Eviscerated Weight (EW) (p<0.05). The SNP genotypes (154T>C) in MyoG were significantly associated with Live Weight (LW), Carcass Weight (CW), Eviscerated Weight (EW) and Breast Muscle Weight (BMW) (p<0.05). The results suggested that Myf5 and MyoG genes are potential major genes or are in close linkage disequilibrium with the QTL affecting carcass traits in this population of chickens. The 2 SNPs may potentially have use as markers for Marker-Assisted Selection (MAS) in chicken breeding.
Preview · Article · Jun 2011 · Journal of Animal and Veterinary Advances
[Show abstract][Hide abstract] ABSTRACT: Adipose differentiation-related protein gene (ADP) plays an important role in controlling lipid accumulation in mammals. It may also affect lipid deposition in birds. However, the molecular mechanism of its actions in birds remains unknown. In the present study, the coding sequence of ADP cDNA for Chinese native breed Sichuan Mountainous Black-bone chicken (MB) was first cloned from abdominal fat using reverse transcription-PCR (RT-PCR). This putative MB ADP cDNA (1,881 bp) encodes an open reading frame of 438 amino acids (AA) and shares high AA sequence identity with that of red jungle fowl (99%), duck (92%), house mouse (70%), human (70%), chimpanzee (70%), pig (70%), domestic cow (69%) and domestic sheep (68%). Further analysis using bioinformatics shows the deduced MB ADP protein has the typical characters of PAT (Perilipin, Adipophilin and Tip47) family. Quantitative real-time PCR (qRT-PCR) analysis revealed that ADP expresses in chicken leg muscle, whole brain, heart, liver, pectoralis muscle, abdominal fat and subcutaneous fat. Ontogenetic expression studies shows ADP expression levels in abdominal fat, subcutaneous fat and pectoralis muscle were prior to that in leg muscles at posthatch day (P) 84. But, its levels in abdominal fat and subcutaneous fat were less than that in leg muscles at P28, 42, 56 and 70, respectively. The ADP expression levels in subcutaneous fat and abdominal fat were stable from P28 to P70 and both were less than their counterparts at P84. However, it changed greatly in pectoralis muscle, liver, brain, heart and leg muscle at all points. Patterns of ADP expression suggest that ADP plays an important role in fat development, but further study is needed to reconfirm its function in a large population and in other breeds with different genetic backgrounds.
[Show abstract][Hide abstract] ABSTRACT: Adipose differentiation-related protein (ADFP) plays all important role in regulating lipid storage and affecting body fat distribution. The objective of the current research was to identify the polymorphisms in chicken ADFP gene and their associations with carcass traits. We screened all coding sequence and part of introns (totally 2155 bp) of the ADFP gene by using single strand conformation polymorphism method in individuals front Sanhuang chicken, Mountainous Black-bone chicken and a commercial crossbred chicken (totally 427 birds). Three novel single-nucleotide polymorphisms were found in intron 4 (SNP1), intron 5 (SNP2) and exon 8 (SNP3), respectively. The association analyses showed that genotypes of SNP I were significantly associated with abdominal fat weight and percentage of abdominal fat (P < 0.05). genotypes of SNP2 were significantly associated with breast muscle weight and percentage of abdominal fat (P < 0.05), and the main haplotype/haplotypes, combination (their frequencies were higher than 5%) were marginally significantly associated with breast muscle weight. abdominal fat weight. and percentage of abdominal fat (0.05 < P < 0.1). Haplotype H2 (A-C-A) was an advantageous haplotype for breast muscle weight and H5 (T-C-G) was an advantageous haplotype for weight and percentage of abdominal fat. Conversely, H3H3 (A-T-G/A-T-G) was a disadvantage haplotype combination for accumulation of abdominal fat. These results suggested that polymorphisms of ADFP gene were associated with carcass traits, especially with fatness traits. ADFP is a potential major gene or in close linkage disequilibrium with the QTL affecting fatness traits in chickens.
No preview · Article · Apr 2009 · The Journal of Poultry Science