Polymorphisms of the Myostatin Gene and Its Relationship with Reproduction Traits in the Bian Chicken

Myostatin, or growth and differentiation factor 8, is a member of the transforming growth factor-β superfamily; it functions as a negative regulator of skeletal muscle development and growth in mammals. In this study, single nucleotide polymorphisms in the 5′ regulatory region and exon 1 of the myostatin gene were detected by PCR–SSCP in the Bian, Jinghai, Youxi, and Arbor Acre chickens, and the associations of the polymorphisms with reproduction traits were analyzed. Seven SNPs (A326G, C334G, C1346T, G1375A, A1473G, G1491A, and G2283A) were found in the myostatin gene. Association analysis showed that the G2283A were significantly associated with reproduction traits. Bian chickens of the GG genotype had a greater age at first egg than those of the GA and AA genotypes (P < 0.01). Correspondingly, Bian chickens of the GA and AA genotypes had larger egg number at 300 days than those of the GG genotype (P < 0.05 and P < 0.01, respectively). Bian chickens of the AA genotype had significantly higher body weight at 300 days than those of the GG genotype (P < 0.05). These results suggested that the myostatin gene may have certain effects on reproduction traits other than merely as a negative regulator of skeletal muscle development and growth in mammals previously reported.     

Impact of an energy- and nutrient-reduced diet containing 10% lignocellulose on animal performance,body composition and egg quality of dual purpose laying hens

In response to ethical concerns regarding the killing of day-old male chicks of layer breeds, the use of dual purpose chickens is increasingly discussed in public while data on nutritional requirements of dual purpose laying hens are not available. The present study examined the impact of an energy- and nutrient-reduced diet containing lignocellulose on performance, body composition and egg quality of dual purpose hens. Female Lohmann Dual chicks were allocated to 12 pens and fed two different diets for 52 weeks: a control (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose. During the trial, animal performance, whole-body composition and egg quality parameters of hens were consistently ascertained. The results showed that LC-fed hens had lower body weights compared to those receiving CON (p < 0.05). During the laying period, feed intake was increased in LC-fed hens (p < 0.001). LC-fed hens showed a higher egg production and egg mass resulting in an improved feed efficiency (p < 0.05) and laid smaller eggs compared to CON-fed hens (p < 0.001). At 52 weeks of age, bodies of LC-fed hens had higher protein and lower fat contents than those fed with CON diet (p ≤ 0.001). Mean body weight was positively correlated to the body fat content (p = 0.004) and body fat content was negatively correlated to the egg production (p = 0.043). Analyses of the egg quality showed that yolk mass at all sampling points and albumen mass at 27 and 42 weeks were lower in hens fed with diet LC compared to those fed with diet CON (p< 0.05). In conclusion, the feeding of energy- and nutrient-reduced diets containing 10% lignocellulose reduced the body fat content and simultaneously improved the laying performance in dual purpose hens.     

Single and combined effects of zinc and cinnamon essential oil in diet on productive performance,egg quality traits,and blood parameters of laying hens reared under cold stress condition

This study was conducted to evaluate the effects of adding zinc (Zn), cinnamon essential oil (Ci), or their combination in diet on productive performance, egg quality, and blood parameters of laying hens reared under cold stress condition (8.8?±?3 °C). Feed intake (FI), feed conversion ratio (FCR), egg weight (EW), egg production (EP), and egg mass (EM) were evaluated during the 56-day trial period using 120 Lohmann LSL-Lite laying hens. Significant interactions between Ci and Zn on FCR, EW, EP, or EM were observed (P?<?0.05). The EP, EM, and EW increased, whereas FCR decreased (P?<?0.05) in the hens fed the diets including Ci and Zn (as single or combined form) compared to those fed the basal diet. There were significant interactions between Ci and Zn on the serum level of glucose and triglycerides as well as plasma concentration of zinc (P?<?0.05), so that serum content of glucose and triglyceride decreased and the plasma content of zinc increased in the hens fed the diets including Ci and Zn (together) compared to those fed the basal diet. From the results of the present experiment, it can be concluded that diet supplementation by the combined form of Ci and Zn could have beneficial effects on performance and blood parameters of hens reared under cold stress condition.     

Genetic variations in chemoattractant receptor expressed on Th2 cells (CRTH2) is associated with asthma susceptibility in Chinese children

We investigated the allele and genotype frequencies of two common CRTH2 single nucleotide polymorphisms (SNPs) [G1544C and A1651G (rs 545659)] in the 3′-untranslated region and the relationship between these SNPs and serum IL-13 levels in Chinese children patients with asthma. For G1544C and A1651G SNPs, there were significant differences in allele and genotype frequencies between asthma patients and controls. Haplotype analysis yielded additional evidence of linkage disequilibrium for the 1544G–1651G haplotype (P < 0.01). Moreover, serum IL-13 levels were significantly different among genotypes in G1544C, A1651G SNPs. These results suggest that SNPs of G1544C and A1651G might be act as susceptibility genetic factors of asthma. Jinhui Wang and Yongchen Xu should be regarded as joint First Authors.     

Two Novel Coding SNPs of SREBP1c Gene are Associated with Body Weight and Average Daily Gain in Bovine

It is known that the SREBP1c gene is an important gene responsible for adipogenesis and regulation of the expression of genes controlling fatty acid biosynthesis. Its expression levels increase in parallel with obesity. Therefore, the present study focused on screening the genetic variation within bovine SREBP1c gene and analyzing its effect on growth traits in 1035 individuals belonging to four Chinese cattle breeds (QC, NY, JX, CH) using PCR-SSCP, DNA sequencing, and forced PCR-RFLP methods. The results revealed two novel mutations: NC_007317: g. 10781 C > A (457aa), 10914 G > A (502aa). Association analysis with growth traits in the Nangyang breed indicated that: The SNPs in the bovine SREBP1c gene had significant effects on body weight and average daily gain at birth, 6 and 12 months old (P < 0.05 or P < 0.01). Therefore, these results suggest that the SREBP1c gene is a strong candidate gene that affects growth traits in cattle.     

Effects of Enterococcus faecalis on egg production,egg quality and caecal microbiota of hens during the late laying period

This study was conducted to determine the effects of diet supplementation of laying hens with Enterococcus faecalis (EF) on egg production, egg quality and caecal microbiota. A total of 360 Hy-Line Brown laying hens (72 weeks old) were divided into three groups with four replicates of 30 birds each. The laying hens were fed with the basal diet (Control), the basal diet + 3.75 · 10⁸ cfu EF/kg (Group I) or the basal diet + 7.5 · 10⁸ cfu EF/kg (Group II). The experiment lasted for 45 d. Eggs and caecal samples were collected at the end of the experiment. Results showed that dietary supplementation with EF did not affect the average daily egg weight, cracked egg rate, mortality and egg quality. However, EF supplementation caused a significantly increased laying rate and decreased feed/egg ratio (p < 0.05). The differences in caecal microbiota between Group II and the Control were significant. The relative abundance of Verrucomicrobia and Cyanobacteria at the phylum level, Rikenellaceae, Christensenellaceae and Veillonellaceae at the family level, and the Faecalibacterium, Christensenellaceae R-7 group and Eubacterium coprostanoligenes group at the genus level changed significantly in Group II compared with the Control (p < 0.05). In conclusion, the tested dietary supplementations with EF improved product performance and affected the caecal microbial community structure of laying hens during the late laying period.     

A Missense Mutation in the Rabbit Melanocortin 4 Receptor (MC4R) Gene is Associated with Finisching Weight in a Meat Rabbit Line

In this study we resequenced 1729 bp of the rabbit melanocortin 4 receptor (MC4 R) gene in 31 rabbits from different breeds/lines and identified ten polymorphisms: one was an indel and 9 were single nucleotide polymorphisms (SNPs). The indel and 5 SNPs were in the 5′-flanking region, 3 were synonymous SNPs and one was a missense mutation (c.101G>A; p.G34D), located in a conserved position of the extracellular tail of the MC4 R protein. The missense mutation was analyzed in a panel of 74 rabbits of different breeds and in 516 performance tested rabbits of a commercial paternal line under selection for growth efficiency. Association analysis indicated that rabbits with the less frequent genotype in this population (DD) had a lighter weight at 70 postnatal days than animals with genotype GD (P < 0.10) and animals with genotype GG (P < 0.05). This is the third study on candidate genes, after those on GH1 and IGF2 that reported a marker associated with finishing weight. Therefore, it seems that a candidate gene approach in rabbit based on previous information accumulated in other livestock species could be useful to identify genes explaining a fraction of variability of performance traits with potential application on rabbit breeding and selection.     

Polymorphism identification in GDF9 gene and its association analysis with reproduction traits in Jinghai Yellow chicken

Abstract

GDF9 (growth differentiation factor 9) belongs to the transforming growth factor-β (TGF-β) superfamily and plays an irreplaceable role in female fertility. To reveal its genetic effects on productivity performance in chickens, 373 Jinghai Yellow chickens were chosen randomly to detect SNPs in GDF9 by PCR-SSCP and DNA sequencing methods. Eventually, four SNPs (g.2053G?>?A, g.2275T?>?C, g.2338C?>?T, g.2420T?>?C) in total had been detected. Amongst them, g.2420T?>?C was first found significantly associated with reproduction trait in chickens and heterozygous type C₂T₂ had higher average egg weight at 300?days of age (AEWD300) than T₂T₂ (p?<?0.01). Least squares analysis showed that age at first laying (AFE) of H1 and H1H1 chickens were significantly earlier than that of H7 and H7H7 ones, respectively (p?<?0.05). H1H5 hens showed higher AEWD300 than H4H7 ones (p?<?0.05). For total egg number at 300?days of age (END300), mean of H5H5 was significantly higher than that of H4H4 (p?<?0.05). Hence, the study suggested that hybrid vigor at g.2420T?>?C could be utilized in practice. H1H1, H1H5 and H5H5 could be the dominant diplotypes for chicken breeding. The study may contribute to the breeding progress of productive chickens and supply reference for oviparous animal production practice.     

Identification of Polymorphisms in the Rabbit Growth Hormone Receptor (GHR) Gene and Association with Finishing Weight in a Commercial Meat Rabbit Line

A shortcut to identify DNA markers associated with economic traits is to use a candidate gene approach that is still useful in livestock species in which molecular tools and resources are not advanced or not well developed. Mutations in the growth hormone receptor (GHR) gene associated with production traits have been already described in several livestock species. For this reason GHR could be an interesting candidate gene in the rabbit. In this study we re-sequenced all exons and non-coding regions of the rabbit GHR gene in a panel of 10 different rabbits and identified 10 single nucleotide polymorphisms (SNPs). One of them (g.63453192C>G or c.106C>G), located in exon 3 was a missense mutation (p.L36V) substituting an amino acid in a highly conserved position across all mammals. This mutation was genotyped in 297 performance tested rabbits of a meat male line and association analysis showed that the investigated SNP was associated with weight at 70 days (P < 0.05). The most frequent genotype (GG) was in animals with higher weight at this age, suggesting that the high directional selection pressure toward this trait since the constitution of the genotyped line might have contributed to shape allele frequencies at this polymorphic site.     

Association of the FADS2 Gene with ω-6 and ω-3 PUFA Concentration in the Egg Yolk of Japanese Quail

This study focused on the association of polymorphisms of the FADS2 gene with fatty acid profiles in egg yolk of eight Japanese quail lines selected for high and low ω-6:ω-3 PUFA ratio (h2 = 0.36–0.38). For the identification of polymorphisms within the FADS2 gene 1350 bp of cDNA sequence were obtained encoding 404 amino acids. Five synonymous SNPs were found by comparative sequencing of animals of the high and low lines. These SNPs were genotyped by single base extension on 160 Japanese quail. The association analysis, comprising analysis of variance and family based association test (FBAT), revealed significant effects of SNP3 and SNP4 genotypes on the egg yolk fatty acid profiles, especially the ω-6 and ω-3 PUFAs (P < 0.05). No effects of the other SNPs were found—indicating that these are not in linkage disequilibrium with the causal polymorphism. The results of this study promote FADS2 as a functional candidate gene for traits related to ω-6 and ω-3 PUFA concentration in the egg yolk.     

Association Between Sexual Precocity and Alleles of KISS-1 and GPR54 Genes in Goats

KISS-1 and GPR54 were regarded as key regulators for the puberty onset and fundamental gatekeepers of sexual maturation in mammals. To explore the possible association between variations in KISS-1 and GPR54 with sexual precocity, mutation screening of exon 1 of KISS-1 and exon 1, exon 3, and partial exon 5 of GPR54 was performed in a sexual precocious breed (Jining Grey goats) and sexual late-maturing breeds (Inner Mongolia Cashmere, Angora, and Boer goats) by PCR-SSCP. The results showed that five novel mutations were identified in exon 1 and partial exon 5 of GPR54 including C96 T, T173C, G176A, G825A, and C981 T. The Jining Grey goats with genotype BB or AB had 1.07 (P < 0.05) or 0.40 (P < 0.05) kids more than those with AA. The Jining Grey goats with genotype DD or CD had 1.80 (P < 0.05) or 0.55 (P < 0.05) kids more than CC, respectively. The present study preliminarily showed an association between alleles B and D of GPR54 with high litter size and sexual precocity in Jining Grey goats.     

Polymorphism detection of promoter region of IFN-$$\gamma $$ and IL-2 genes and their association with productive traits in Mazandaran native breeder fowls

To identify polymorphism in interferon gamma (IFN-\(\upgamma \)) and interleukin-2 (IL-2) genes, blood samples were collected from 380 breeder hens of the Mazandaran native fowls breeding station. DNA extraction was performed through a modified salting-out method and fragments of 670 and 659 bp from the promoter regions of IFN-\(\upgamma \) and IL-2 genes were amplified by using specific primers, respectively. Following genotyping in the IFN-\(\upgamma \) gene using the Tsp509I restriction enzyme, two alleles of A and G with the frequencies of 0.55 and 0.45 and three genotypes of AA, AG and GG were observed with the frequencies of 0.32, 0.46 and 0.22, respectively. For the IL-2 gene, two alleles of A and G were also detected using the MnlI restriction enzyme with the frequencies of 0.58 and 0.42 and three genotypes of AA, AG and GG with the frequencies of 0.33, 0.50 and 0.17, respectively. Statistical analysis revealed significant associations between IL-2 gene single-nucleotide polymorphism and productive traits including the average egg weight (EW) at 345–375 days of age, egg number (EN) at 345–375 days of age and body weight (BW) at 8 weeks of age traits (\(P{<}0.05\)). Further, in a mean comparison analysis, there were also significant differences between different genotypes of the IL-2 gene in average EW at 28 and 30 weeks of age, in which AG genotypes showed higher performance. Additionally, for the IFN-\(\upgamma \) gene, a significant difference was found between the genotypes in average EW at 28 weeks of age trait. Therefore, it can be concluded that the above-mentioned polymorphisms could be considered as the pivotal genetic makers to improve Mazandaran native fowl breeding programmes to achieve the optimum performance in productive traits more efficiently.     

Genetic Polymorphisms in the Bovine Toll-Like Receptor 4 (TLR4) and Monocyte Chemo Attractant Protein-1(CCL2) Genes: SNPs Distribution Analysis in Bos indicus Sahiwal Cattle Breed

Toll-like receptor 4 gene (TLR4) that recognizes the Gram negative bacterial ligand LPS was sequenced in the Bos indicus Sahiwal cattle breed. Ninety four single nucleotide polymorphisms (SNPs) were detected within 10.8 kb gene region. Seventeen of the SNPs were in the coding regions and the one at position 9589(A > G) in exon3 resulted in an amino acid change from Valine to Isoleucine. These SNPs led to generation of 27 TLR4 gene haplotypes. All the Sahiwal animals studied presently showed the occurrence of the genotype CC at gene position 9662, which codes for the amino acid threonine at position 674 of the TLR4 protein, and which had been reported to be associated with lower somatic cell score and, therefore, a lower susceptibility to mastitis, in Taurus cattle. This nucleotide configuration of the Toll-like receptor 4 gene of the Bos indicus Sahiwal cattle breed could possibly indicate toward a lower susceptibility to mastitis in the Sahiwal animals. Monocyte chemo-attractant protein-1 (CCL2) gene encoding for small inducible cytokine A2 that belongs to the CC chemokine family was also sequence characterized in these Sahiwal animals. The CCL2 gene was observed to have 12 polymorphic sites in 3.3 kb region of which one SNP at position 2500 (A > G) in exon 3 resulted in amino acid change from Valine to Isoleucine at position 46 of the mature CCL2 peptide. Seventeen haplotypes of the CCL2 gene were predicted corresponding to 12 genotypes detected.     

Polymorphisms in vitamin D receptor, osteopontin, insulin-like growth factor 1 and insulin, and their associations with bone, egg and growth traits in a layer--broiler cross in chickens

Bone strength traits in chickens are gaining importance due to economic losses and welfare concerns associated with bone fractures and other abnormalities. A chicken F2 resource population was generated from layer and broiler genetic lines, and traits relating to bone strength, egg production, egg quality and growth rate were measured in approximately 500 F2 hens. Four biological candidate genes (vitamin D receptor, VDR; insulin, INS; insulin-like growth factor 1, IGF1; and osteopontin, SPP1) were selected for investigation. Single nucleotide polymorphisms (SNPs) were identified for each candidate gene by comparing sequences between grandparent lines. Polymerase chain reaction restriction-fragment length polymorphism or SNaPshot assays were developed to genotype the F2 population and to evaluate associations between each SNP genotype and multiple phenotypes. Significant associations (P < 0.0125) were found between VDR and bone mineral content of the humerus at 35 weeks of age; between IGF1 and SPP1 and 5-week body weight; and between INS and 55-week body weight.     

Time-of-day effects of exposure to solar radiation on thermoregulation during outdoor exercise in the heat

High solar radiation has been recognised as a contributing factor to exertional heat-related illness in individuals exercising outdoors in the heat. Although solar radiation intensity has been known to have similar time-of-day variation as body temperature, the relationship between fluctuations in solar radiation associated with diurnal change in the angle of sunlight and thermoregulatory responses in individuals exercising outdoors in a hot environment remains largely unknown. The present study therefore investigated the time-of-day effects of variations in solar radiation associated with changing solar elevation angle on thermoregulatory responses during moderate-intensity outdoor exercise in the heat of summer. Eight healthy, high school baseball players, heat-acclimatised male volunteers completed a 3-h outdoor baseball trainings under the clear sky in the heat. The trainings were commenced at 0900 h in AM trial and at 1600 h in PM trial each on a separate day. Solar radiation and solar elevation angle during exercise continued to increase in AM (672–1107 W/m² and 44–69°) and decrease in PM (717–0 W/m² and 34–0°) and were higher on AM than on PM (both P < 0.001). Although ambient temperature (AM 32–36°C, PM 36–30°C) and wet-bulb globe temperature (AM 31–33°C, PM 34–27°C) also continued to increase in AM and decrease in PM, there were no differences between trials in these (both P > 0.05). Tympanic temperature measured by an infrared tympanic thermometer and mean skin temperature were higher in AM than PM at 120 and 180 min (P < 0.05). Skin temperature was higher in AM than PM at the upper arm and thigh at 120 min (P < 0.05) and at the calf at 120 and 180 min (both P < 0.05). Body heat gain from the sun was greater during exercise in AM than PM (P < 0.0001), at 0–60 min in PM than AM (P < 0.0001) and at 120–180 min in AM than PM (P < 0.0001). Dry heat loss during exercise was greater at 0–60 min (P < 0.0001), and lower at 60–120 min (P < 0.05) and 120–180 min (P < 0.0001) in AM than PM. Evaporative heat loss during exercise was greater in PM than AM at 120–180 min (P < 0.0001). Total (dry + evaporation) heat loss at the skin was greater during exercise in PM than AM (P < 0.0001), at 0–60 min in AM than PM (P < 0.0001) and at 60–120 and 120–180 min in PM than AM (P < 0.05 and 0.0001). Heart rate at 120–150 min was also higher in AM than PM (P < 0.05). Neither perceived thermal sensation nor rating of perceived exertion was different between trials (both P > 0.05). The current study demonstrates a greater thermoregulatory strain in the morning than in the afternoon resulting from a higher body temperature and heart rate in relation to an increase in environmental heat stress with rising solar radiation and solar elevation angle during moderate-intensity outdoor exercise in the heat. This response is associated with a lesser net heat loss at the skin and a greater body heat gain from the sun in the morning compared with the afternoon.     

Effect of Selenium from Selenium-Enriched Kale Sprout Versus Other Selenium Sources on Productivity and Selenium Concentrations in Egg and Tissue of Laying Hens

A 6-week trial was conducted to compare the effect of selenium (Se) from hydroponically produced Se-enriched kale sprout (HPSeKS), sodium selenite (SS), and Se-enriched yeast (SeY) in laying hens. A total of 144 40-week-old hens were randomly divided into four groups, according to a completely randomized design. Each group consisted of four replicates with nine hens per replicate. The dietary treatments were T1 (basal diet) and T2, T3, and T4 (basal diets supplemented with 0.30 mg Se/kg from SS, SeY, and HPSeKS, respectively). Results showed that Se supplement did not affect (p > 0.05) productivity and egg quality. Hens fed Se from HPSeKS and SeY exhibited higher (p < 0.05) Se bioavailability than hens fed Se from SS. Whole egg Se concentration of hens fed Se from HPSeKS was similar (p > 0.05) to that of hens fed Se from SeY, but higher (p < 0.05) than that of hens fed Se from SS. However, the breast muscle and heart tissue Se concentrations of hens fed Se from SS, SeY, and HPSeKS were not different (p > 0.05). The results of this trial demonstrated that Se from HPSeKS and SeY was more efficient than Se from SS on Se bioavailability and whole egg Se concentration in laying hens.     

Genetic Variants in SDC3 Gene are Significantly Associated with Growth Traits in Two Chinese Beef Cattle Breeds

Identification of the genes and polymorphisms underlying quantitative traits, and understanding these genes and polymorphisms affect economic growth traits, are important for successful marker-assisted selection and more efficient management strategies in commercial cattle (Bos taurus) population. Syndecan-3 (SDC3), a member of the syndecan family of type I transmembrane heparan sulfate proteoglycans is a novel regulator of feeding behavior and body weight. The aim of this study is to examine the association of the SDC3 polymorphism with growth traits in Chinese Jiaxian and Qinchuan cattle breeds (). Four single nucleotide polymorphisms (SNPs: 1–4) were detected in 555 cows from three Chinese native cattle breeds by means of sequencing pooled DNA samples and polymerase chain reaction-single stranded conformational polymorphism (PCR-SSCP) methods. We found one SNP (g.28362A > G) in intron and three SNPs (g.30742T > G, g.30821C > T and 33418 A > G) in exons. The statistical analyses indicated that these SNPs of SDC3 gene were associated with bovine body height, body length, chest circumference, and circumference of cannon bone (P < 0.05). The mutant-type variant was superior for growth traits; the heterozygote was associated with higher growth traits compared to wild-type homozygote. Our result confirms the polymorphisms in the SDC3 gene are associated with growth traits that may be used for marker-assisted selection in beef cattle breeding programs.     

Interactions of flavin containing monooxygenase 3 (FMO3) genotype and feeding of choline and rapeseed cake on the trimethylamine (TMA) content in egg yolks of laying hens

To evaluate the relationship between the FMO3 genotype and dietary trimethylamine (TMA) precursors on TMA-N content in eggs, laying hens were fed with choline (500 and 4000 mg/kg diet) and, in a later trial, with rapeseed cake (0, 100 and 300 g/kg diet). Hens were genotyped for non-synonymous A/T polymorphism at position nt1034 of the cDNA of the FMO3 gene, which is associated with elevated TMA-levels in egg yolks. Genotypes were equally distributed among the experimental diets. TMA was extracted from yolks and measured as TMA-N by a colorimetric method. As expected, hens of the TT-genotype had high amounts of TMA-N in egg yolks when fed either 4000 mg choline/kg diet or the rapeseed cake diet, while hens of the AA-genotype showed low levels of TMA-N. Heterozygous AT-hens had a slightly increased level of TMA-N when fed with 4000 mg choline/kg diet but not with the rapeseed cake feed. Rapeseed cake can be fed to AA and AT hens without leading to fishy tainted eggs.