Age-related expression profile of the <Emphasis Type="Italic">SLC27A1</Emphasis> gene in chicken tissues

The solute carrier family 27 (SLC27, also known as fatty acid transport proteins [FATPs]) plays important biological roles in cells. However, there is no report about the expression profile of SLC27 member in chicken. In this study, we quantified the expression of SLC27A1 (FATP1) mRNA in a mountainous black-boned chicken breed (MB) and a commercial meat type chicken breed (S01), to discern the tissue and age-related specific expression pattern and their potential involvement in fat deposition and muscle fatty acid metabolism. Real-time quantitative PCR assays were developed for accurate measurement of SLC27A1 mRNA levels in different tissues from chicken with different ages (0–12 weeks). Expression of SLC27A1 mRNA was detected in all tissues examined. There was a significantly age-related change of the SLC27A1 mRNAs in heart, breast muscle (BMW), leg muscle (LMW), liver, and abdominal fat (AF) tissues (P < 0.05). The breast muscle and leg muscle tissues had the highest expression of SLC27A1 mRNA than the other tissues from the same individual at 0, 2 and 4 weeks. The overall SLC27A1 mRNA level exhibited a “rise-decline” developmental change in all tissues except for breast muscle, subcutaneous fat, and brain. The S01 chicken had a higher expression of the SLC27A1 mRNA in breast muscle, subcutaneous fat, and heart tissues than the MB chicken. Our results showed that the expression of SLC27A1 mRNA in chicken tissues exhibits specific developmental changes and age-related patterns.     

Characterization of the expression profile of <Emphasis Type="Italic">calpain</Emphasis>-<Emphasis Type="Italic">3</Emphasis> (<Emphasis Type="Italic">CAPN3</Emphasis>) gene in chicken

Calpain-3 is a skeletal muscle-specific protease and participates in the regulation of myogenesis. In this study, we quantified the expression of calpain-3 (CAPN3) mRNA in a Chinese local chicken breed (Sichuan Mountainous Black-boned chicken [MB]), to discern the tissue and ontogenic expression pattern. Meanwhile, we compared the CAPN3 mRNA expression pattern in MB chicken at 10 weeks with a commercial meat type chicken line (S01) of the same age to identify the unique expression pattern under different genetic background. A real time quantitative PCR (qRT-PCR) assay was developed for an accurate measurement of its expression in various tissues from chickens at different ages (0, 2, 4, 6, 8, 10, and 12 weeks). Expression of the CAPN3 mRNA was detected in the selected tissues, regardless of age. The breast muscle and leg muscle tissues had a significantly higher expression than the other tissues from the same individual (P < 0.01). Overall, the CAPN3 mRNA level exhibited a “rise-decline” developmental change in detected tissues except for brain. The S01 chicken had a higher expression of the CAPN3 mRNA in detected tissues than the MB chicken at 10 weeks. The present expression data of chicken CAPN3 gene may provide some information to shed light on the tissue and ontogenic expression pattern during chicken development.     

Liver dominant expression of fatty acid synthase (FAS) gene in two chicken breeds during intramuscular-fat development

Fatty acid synthase (FAS) is a key enzyme of lipogenesis. In this study, the FAS mRNA expression patterns were examined in three fat related tissues (liver, breast and thigh) at different developmental stages in two chicken breeds (Beijing-You, BJY and Arbor Acres broiler, AA). Results of the Real time-qPCR showed that the expression of FAS mRNA level in liver was significantly higher (P < 0.01) than that in breast and thigh in both two chicken breeds. Significant differences of FAS mRNA expression in liver were found between BJY and AA chickens during different developmental stages. After the contents of intramuscular-fat (IMF) and the liver fat were measured, the correlation analysis was performed. In liver, the FAS mRNA level was highly correlated with hepatic fat content (r = 0.891, P < 0.01 for BJY; r = 0.901, P < 0.01 for AA). On the contrary, the FAS expression level in both breast and thigh tissues were relatively low, stable and there was no correlation between the FAS mRNA level and IMF content in breast and thigh tissues of each breed. The results here can contribute to the knowledge on the developmental expression pattern of FAS mRNA and facilitate the further research on the molecular mechanism underlying IMF deposition in chicken.     

Identification and characterization of adipose triglyceride lipase (ATGL) gene in birds

Adipose triglyceride lipase (ATGL) is a triglyceride hydrolysis lipase and is generally related to lipid metabolism in animals. The ATGL gene was well studied in mammals, however very less was known in birds that differed significantly with mammals for lipid metabolism. In this study, cloning, mRNA real time and association analysis was performed to characterize the ATGL gene in birds. Results showed that the obtained ATGL gene cDNA of parrot, quail, duck were 1,651 bp (NCBI accession number: GQ221784), 1,557 bp (NCBI accession number: GQ221783) and 1,440 bp each, encoded 481-, 482- and 279-amino acid (AA) peptide, respectively. The parrot ATGL (pATGL) gene was found to predominantly express in breast muscle and leg muscle, and very higher ATGL mRNA level was also found in heart, abdominal fat and subcutaneous fat. The quail ATGL (qATGL) gene was also predominantly expressed in breast muscle and leg muscle, and then to a much lesser degree in heart. The duck ATGL (dATGL) gene was found to predominantly express in subcutaneous fat and abdominal fat, quite higher ATGL mRNA was also found in heart, spleen, breast muscle and leg muscle. Blast analyses indicated the high homology of ATGL and its patatin region, and moreover, and the active serine hydrolase motif (“GASAG” for “GXSXG”) and the glycine rich motif (“GCGFLG” for “GXGXXG”) were completely conservative among 14 species. Association analyses showed that c.950+24C>A, c.950+45C>G, c.950+73G>A, c.950+83C>T and c.950+128delA of chicken ATGL gene (cATGL) were all significantly or highly significantly with cingulated fat width (CFW) (P < 0.05 or P < 0.01), and c.777−26C>A, c.950+45C>G, c.950+73G>A and c.950+118C>T were all significantly or highly significantly with pH value of breast muscle (BMPH) (P < 0.05).     

Investigating the heat tolerance and production performance in local chicken breed having normal and dwarf size

Heat stress significantly impairs the growth performance of broilers, which causes serious losses to the poultry industry every year. Thus, understanding the performance of indigenous chicken breeds under such environment is crucial to address heat stress problem. The purpose of this study was to investigate the effects of heat stress (HS) on production performance, tissue histology, heat shock response (HSP70, HSP90), and muscle growth-related genes (GHR, IGF-1, and IGF-1R) of Normal yellow chicken (NYC) and Dwarf yellow chicken (DYC). Seventy-two female birds from each strain were raised under normal environmental conditions up to 84 days, with birds from each strain being divided into two groups (HS and control). In the HS group, birds were subjected to high temperature at 35 ± 1 °C for 8 h daily and lasted for a week, while in the control group, birds were raised at 28 ± 1 °C. At 91 days old, bird's liver, hypothalamus, and breast muscle tissues were collected to evaluate the gene expression, histological changes, and the production performance. The Feed intake, weight gain ratio, total protein intake and protein efficiency ratio showed a significant reduction in the treatments (P < 0.01) and treatment × strain interaction (P < 0.05) with breast muscle rate significantly reducing among the treatments (P < 0.01) after 7 days of HS. Correspondingly, total abdominal fat showed significant change among treatment and strain (P < 0.01, P < 0.05), respectively. Besides, HS markedly upregulated the mRNA expression of HSP70 and HSP90 in the pectoralis major of both chicken strains, but no significant increase (P < 0.05) was found in mRNA expression of HSP90 in liver and hypothalamus tissues of both chicken strains. Moreover, HS significantly upregulated (P < 0.05) the expression of lipogenic genes (FASN, ACC) in liver tissues of NYC, while mRNA expression of these genes showed no variation in DYC. Similarly, HS downregulated the mRNA expression of muscle growth-related genes (GHR, IGF-1, and IGF-1R). Consequently, the histopathological analysis showed that histological changes were accompanied by inflammatory cell infiltration in liver tissues of both chicken strains; however, histopathological changes were more severe in NYC than dwarf chicken strain. Conclusively, this study depicted that the production performance and growth rate varied significantly between treatment and control group of NYC. However, heat treatment in DYC has not shown significant damaging consequences as compared to the control group that signifies the vital role of the dwarf trait in thermal tolerance.     

Polymorphism of chicken myocyte-specific enhancer-binding factor 2A gene and its association with chicken carcass traits

Myocyte-specific enhancer-binding factor 2A (MEF2A) gene is a member of the myocyte-specific enhancer-binding factor 2 (MEF2) protein family which involved in vertebrate skeletal muscle development and differentiation. The aim of the current study is to investigate the potential associations between MEF2A gene SNPs (single nucleotide polymorphisms) and the carcass traits in 471 chicken samples from four populations. Three new SNPs (T46023C, A72626G, and T89232G) were detected in the chicken MEF2A gene. The T46023C genotypes were associated with live body weight (BW), carcass weight (CW), eviscerated weight, semi-eviscerated weight (SEW), and leg muscle weight (LMW) (P < 0.05); the A72626G genotypes were associated with BW, CW, LMW (P < 0.01) and breast muscle weight (BMW), leg muscle percentage (LMP) (P < 0.05); whereas the T89232G genotypes were associated with carcass percentage (CP) and semi-eviscerated percentage (SEP) (P < 0.05). The haplotypes constructed on the three SNPs were associated with BW, CW, LMW (P < 0.01), SEW, BMW, CP (P < 0.05). Significantly and suggestive dominant effects of diplotype H1H2 were observed for BW, CW, SEW, BMW and CP, whereas diplotype H5H5 had a negative effect on BW, CW, SEW, BMW and LMW. Our results suggest that the MEF2A gene may be a potential marker affecting the muscle trait of chickens.     

Protein kinase D1 regulates ERα‐positive breast cancer cell growth response to 17β‐estradiol and contributes to poor prognosis in patients

About 70% of human breast cancers express and are dependent for growth on estrogen receptor α (ERα), and therefore are sensitive to antiestrogen therapies. However, progression to an advanced, more aggressive phenotype is associated with acquisition of resistance to antiestrogens and/or invasive potential. In this study, we highlight the role of the serine/threonine‐protein kinase D1 (PKD1) in ERα‐positive breast cancers. Growth of ERα‐positive MCF‐7 and MDA‐MB‐415 human breast cancer cells was assayed in adherent or anchorage‐independent conditions in cells overexpressing or depleted for PKD1. PKD1 induces cell growth through both an ERα‐dependent manner, by increasing ERα expression and cell sensitivity to 17β‐estradiol, and an ERα‐independent manner, by reducing cell dependence to estrogens and conferring partial resistance to antiestrogen ICI 182,780. PKD1 knockdown in MDA‐MB‐415 cells strongly reduced estrogen‐dependent and independent invasion. Quantification of PKD1 mRNA levels in 38 cancerous and non‐cancerous breast cell lines and in 152 ERα‐positive breast tumours from patients treated with adjuvant tamoxifen showed an association between PKD1 and ERα expression in 76.3% (29/38) of the breast cell lines tested and a strong correlation between PKD1 expression and invasiveness (P < 0.0001). In tamoxifen‐treated patients, tumours with high PKD1 mRNA levels (n = 77, 50.66%) were significantly associated with less metastasis‐free survival than tumours with low PKD1 mRNA expression (n = 75, 49.34%; P = 0.031). Moreover, PKD1 mRNA levels are strongly positively associated with EGFR and vimentin levels (P < 0.0000001). Thus, our study defines PKD1 as a novel attractive prognostic factor and a potential therapeutic target in breast cancer.     

Associations of <Emphasis Type="Italic">GHSR</Emphasis> gene polymorphisms with chicken growth and carcass traits

Ghrelin receptor (GHSR), or growth hormone secretagogue receptor, modulates many physiological effects by binding to its ligand and therefore is a candidate gene for chicken production performance. In this study, five polymorphisms (four SNP and a ‘GGTACA’ indel) of GHSR gene were genotyped in a F₂ full sib chicken population to investigate their associations with production traits. Results showed that c.739 + 726T > C (M2) was significantly associated with body weight (BW) at 28 days (BW28), BW90, dressed weight, eviscerated weight, eviscerated weight with giblet, breast muscle weight and leg muscle weight (P < 0.05). Meanwhile, T allele rather than C was positive for chicken body weight gain as individuals with CC had the lowest value of all traits. Otherwise, no significant association of c.264G > A (M1), c.3211-196_3211-181delGGTACA (M3), c.3211 + 75C > T (M4), and c.3211 + 150C > T (M5) with any growth and carcass traits was found. Haplotypes based on five polymorphisms were significantly associated with hatch weight, BW7, BW14, BW21 and breast angle (P < 0.05), as well as BW28 (P < 0.01). Therefore, it was concluded that M2 of the GHSR gene and the analyzed haplotypes were associated with some chicken growth and carcass traits.     

Regulation of zinc transporters by dietary flaxseed lignan in human breast cancer xenografts

Zinc is essential for cell growth. Previous studies have shown that zinc concentration in breast cancer tissues is higher than that in normal breast tissues. Zinc cannot passively diffuse across cell membranes and specific zinc transporter proteins are required. Two gene families have been identified involved in zinc homeostasis. ZnT transporters reduce intracellular zinc while ZIP transporters increase intracellular zinc. In this study, three human zinc transporter members: ZnT-1, ZIP2 and LIV-1 were chosen. We aimed to determine the effect of flaxseed lignan on the growth of ER-negative breast cancer cells in a nude mice model and observe the effect of flaxseed lignan on the regulation of the three zinc transporter in mRNA level. Nude mice were xenografted with human breast cancer cell line MDA-MB-231 and 6 weeks later were fed either the basal diet (BD) or BD supplemented with 10% FS and SDG for 5 weeks. The SDG levels were equivalent to the amounts in the 10% FS. RT-PCR was performed. Compared with the BD group, the tumor growth rate was significantly lower (P < 0. 05) in the FS and SDG group. ZnT-1 mRNA level in mammary tumor was increased in SDG group and decreased in FS group, but no significant difference was found. Extremely low amplification of ZIP2 from mRNA was detected, with no difference between the treatment groups. LIV-1 mRNA expression of SDG group increases compared with BD group. In FS group, it significantly increases nearly 9 times than that in BD group (P < 0. 005).     

Effects of chromium picolinate supplementation on the growth,carcass quality and gene expression of beef during the finishing period

Four groups of 12 young beef, as similar as possible with respect to age and weight, were fed a basic diet. The addition fed to four groups was 0, 200, 600, and 1,200 mg of organic chromium (chromium picolinate CrPic) per kg concentrated feed. The results showed that there was no effect on overall growth performance and dressing percentage and pure meat percentage when adding different CrPic content, but significant difference was found between 0 group and other three groups in percentage of high grade cuts (P < 0.05). The Cr content in Kidney, Musculus diaphragm, Semitendinosus muscles and Longissimusdorsi tissues have no difference in four groups (P > 0.05), but there was significant difference in liver tissues between 0, 200, 600 groups and 1200 group (P < 0.05). Gene expression analysis indicated that there were no differences in five genes expression in liver and muscle tissues in four groups (P > 0.05), but mRNA expression amount of FOX1, FSTL and MATR3 always had same trends whatever in liver or muscle tissues. However the RPLOP gene expression amount has large difference between liver and muscle.     

Folic acid rivals methylenetetrahydrofolate reductase (MTHFR) gene-silencing effect on MEPM cell proliferation and apoptosis

Rates of fatty acid oxidation increase rapidly in both rat heart and skeletal muscle in the early postnatal period. Therefore, we examined in heart and soleus muscle, (a) whether there were rapid changes in fatty acid transporter (FAT/CD36, FABPpm) mRNA and protein expression early in life (days 10 –36) and thereafter (days 84, 160, 365), and (b) whether the rates of fatty acid transport and the plasmalemmal content of FAT/CD36 and FABPpm were altered. Protein expression was altered rapidly from day 10–36 in both heart (FAT/CD36 only, +21%, P < 0.05)) and soleus muscle (FAT/CD36 + 100%, P < 0.05; FABPpm −20%, P < 0.05), with no further changes thereafter (P < 0.05). Rates of fatty acid transport (day 10 vs day 160) were increased in heart (+33%, P < 0.05) and muscle (+85%, P < 0.05), and were associated with concomitant increases in plasmalemmal FABPpm (+44%, P < 0.05) and FAT/CD36 (+16%, P < 0.05) in the heart, and only plasmalemmal FAT/CD36 in muscle (+90%, P < 0.05). Therefore, known changes in the rates of fatty acid oxidation in heart and muscle early in life appear to be accompanied by a concurrent upregulation in the rates of fatty acid transport and the expression of FAT/CD36 in heart and muscle, as well as an increase in plasmalemmal FAT/CD36 and FABPpm in the heart, and only plasmalemmal FAT/CD36 in soleus muscle. We speculate that the rapid upregulation of fatty acid transport rates in heart and muscle are needed to support the increased rates of fatty oxidation that have been previously observed in these tissues.     

The effect of age and castration on the growth rate,blood lipid profile,liver histology and feed conversion in Green-legged Partridge cockerels and capons

The surgical castration of male chickens induces hormonal changes, which permanently influence metabolic processes in birds. The aim of this study was to determine the effect of age and castration on the growth rate, feed conversion, lipid profile and histopathological changes in the livers of cockerels and capons. The experimental materials comprised male chickens of the Green-legged Partridge breed (old traditional Polish chicken breed), raised to 28 weeks of age. At 8 weeks of age, 100 birds were castrated. Caponization had a significant effect on the plasma concentrations of total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol and triacylglycerols (P<0.05). Fatty degeneration and lymphoid cell infiltration were observed more frequently in the livers of capons than cockerels. Capon carcasses were characterized by increased deposition of abdominal and subcutaneous fat (P<0.05). Total meat weight in the carcasses of cockerels and capons was similar, but the proportions of muscles were different. From 20 weeks of age, the weight of breast muscles was higher, and the weight of leg muscles was lower in capons than in cockerels (P<0.05). Capons were characterized by higher liver weight, higher gizzard weight and lower heart weight than cockerels (P<0.05). The feed conversion ratio (kg/kg BW) was similar in intact cockerels and capons. The values of carcass quality parameters and feed conversion ratio as well as histopathological changes in the liver indicate that Green-legged Partridge capons should be slaughtered at 20 to 24 weeks of age.     

Evaluation of physiological and molecular responses to acute heat stress in two chicken breeds

High environmental temperatures are a foremost concern affecting poultry production; thus, understanding and controlling such conditions are vital to successful production and welfare of poultry. In view of this, a completely randomized design with a 2 × 2 factorial arrangement involving two local strains (Kirin chicken (KC) and Three-yellow chicken (TYC)) and two temperature groups (normal/control = 30 ± 2 °C and acute heat stress (AHS) = 35 ± 1 °C for 8-h with 70% humidity) was used to assess the main regulatory factors such as heat shock protein (HSP70) gene, cytokine genes (IL-1β, IL-6, IL-10), muscle development gene (IGF-1) and tissue histopathological changes. At 56 days old, the temperatures of the comb (CT), feet (FT), eyelid (ET) and rectal (RT) from each group were taken thrice at 0, 2, 4 and 8-h during AHS, and 1 and 3-h recovery period after AHS. At 80 days old, the slaughter weight was also analyzed. The CT and ET of the AHS groups increased during the 8-h trial, while the RT of both strains decreased significantly at 4 h but increased at 8 h in the TYC group. All temperature recordings dropped in the AHS groups of both strains during the recovery period. The results revealed that the mRNA expression of HSP70 in the liver was higher in the heat-stressed group of both strains compared to the control. The expression of HSP70 was shown in the AHS-KC group to be significantly high compared to the control (P < 0.05). Moreover, the IGF1 gene in the liver, breast muscle and leg muscle was downregulated in the AHS-TYC group compared to the control (P < 0.05), although that in the AHS-KC was downregulated in the breast muscle. The mRNA expression of spleen IL-1β significantly decreased in the AHS-TYC group (P < 0.01), whereas that of the AHS-KC had no significant difference (P > 0.05). The mRNA expression of spleen IL-6 and IL-10 was increased in the AHS-KC group but did not exhibit obvious changes in the AHS-TYC. Correspondingly, the histopathological examinations revealed tissue injury in the AHS groups of both strains, with the TYC strain experiencing more severe changes. The final live and carcass weights showed a significant enhancement in the treatments (P < 0.01 and P < 0.05, respectively) and treatment × strain interaction (P < 0.05) with breast muscle rate significantly reducing among the treatments (P < 0.01) at 80 days. In conclusion, the differential response to AHS after physiological, molecular and immune response portrays KC to have better thermal tolerance than the TYC.     

Differences in egg deposition of corticosterone and embryonic expression of corticosterone metabolic enzymes between slow and fast growing broiler chickens

Glucocorticoids (GCs) are vital for embryonic development and their bioactivity is regulated by the intracellular metabolism involving 11β-hydroxysteroid dehydrogenases (11β-HSDs) and 20-hydroxysteroid dehydrogenase (20-HSD). Here we sought to reveal the differences in egg deposition of corticosterone and embryonic expression of corticosterone metabolic enzymes between slow and fast growing broiler chickens (Gallus gallus). Eggs of fast-growing breed contained significantly higher (P < 0.05) corticosterone in the yolk and albumen, compared with that of a slow-growing breed. 11β-HSD1 and 11β-HSD2 were expressed in relatively higher abundance in the liver, kidney and intestine, following similar tissue-specific ontogenic patterns. In the liver, expression of both 11β-HSD1 and 11β-HSD2 was upregulated (P < 0.05) towards hatching, yet 20-HSD displayed distinct pattern showing a significant decrease (P < 0.05) on posthatch day 1 (D1). Hepatic mRNA expression of 11β-HSD1 and 11β-HSD2 was significantly higher in fast-growing chicken embryos at all the embryonic stages investigated and so was the hepatic protein content on embryonic day of 14 (E14) for 11β-HSD1 and on E14 and D1 for 11β-HSD2. 20-HSD mRNA was higher in fast-growing chicken embryos only on E14. Our data provide the first evidence that egg deposition of corticosterone, as well as the hepatic expression of glucocorticoid metabolic enzymes, differs between fast-growing and slow-growing chickens, which may account, to some extent, for the breed disparities in embryonic development.     

Acute and long-term effects of resistance exercise with or without protein ingestion on muscle hypertrophy and gene expression

The effects of timed ingestion of high-quality protein before and after resistance exercise are not well known. In this study, young men were randomized to protein (n = 11), placebo (n = 10) and control (n = 10) groups. Muscle cross-sectional area by MRI and muscle forces were analyzed before and after 21 weeks of either heavy resistance training (RT) or control period. Muscle biopsies were taken before, and 1 and 48 h after 5 × 10 repetition leg press exercise (RE) as well as 21 weeks after RT. Protein (15 g of whey both before and after exercise) or non-energetic placebo were provided to subjects in the context of both single RE bout (acute responses) as well as each RE workout twice a week throughout the 21-week-RT. Protein intake increased (P ≤ 0.05) RT-induced muscle cross-sectional area enlargement and cell-cycle kinase cdk2 mRNA expression in the vastus lateralis muscle suggesting higher proliferating cell activation response with protein supplementation. Moreover, protein intake seemed to prevent 1 h post-RE decrease in myostatin and myogenin mRNA expression but did not affect activin receptor IIb, p21, FLRG, MAFbx or MyoD expression. In conclusion, protein intake close to resistance exercise workout may alter mRNA expression in a manner advantageous for muscle hypertrophy.