Wenzhong Liu

Coordinated microRNA and messenger RNA expression profiles for understanding sexual dimorphism of gonads and the potential roles of microRNA in the steroidogenesis pathway in Nile tilapia (Oreochromis niloticus).

Sexual dimorphism is a widespread phenomenon in animals. However, the potential role of microRNAs (miRNAs) in regulating this dimorphism is not fully understood. In our study, we used an integrated approach to identify functional targets of miRNA by combining the paired expression profiles of miRNAs and messenger RNAs (mRNAs) in ovaries and testes of young Nile tilapia, Oreochromis niloticus. The results revealed that 67 upregulated and nine downregulated miRNAs and 2299 upregulated and 3260 downregulated genes were identified in the ovary compared with those in the testis (P < 0.01). The target genes of differentially expressed miRNAs were predicted and overlapped with the differentially expressed mRNAs. Furthermore, Kyoto Encyclopedia of Genes and Genomes pathway analyses were conducted in these coincident genes. By correlating miRNA-mRNA and predicting computational target, two types of negatively regulatory miRNA-mRNA correlations (upregulated or downregulated miRNA and downregulated or upregulated mRNA) were obtained. Seven functional miRNA-target gene pairs, miR-17-5p/DMRT1, miR-20a/DMRT1, miR-138/CYP17A2, miR-338/CYP17A2, miR-200a/CYP17A2, miR-456/AMH, and miR-138/AMH, were predicted at the sequence level and further detected by real-time polymerase chain reaction on the basis of the significantly negative relationships. Our results suggest that the integrated analysis of miRNA and mRNA expression profiling can provide novel insights into the molecular mechanism of sexual dimorphism.

Distribution and quantification of β-3 adrenergic receptor in tissues of sheep

The β-3 adrenergic receptor (ADRB3) is a G-protein coupled receptor involved in regulating lipolysis, as part of homeostatic regulation. In this study, South African Mutton Merino and Shanxi Dam Line were used to study the distribution and quantification of ADRB3 in adipose (subcutaneous, omental, retroperitoneal, mesenteric and perirenal fat) and non-adipose (heart, liver, spleen, lung and kidney) tissues of sheep. The protein was determined by immunohistochemical technique and by mRNA abundance via real-time polymerase chain reaction. ADRB3 was detected in all studied tissues with abundance in adipose tissues higher than in non-adipose tissues (P < 0.001). For adipose tissues, greater expression was found in deep deposits such as great omental and retroperitoneal fat than in subcutaneous fat (P < 0.05). Significant differences (P < 0.05) both for mRNA and for protein expression also existed between the two sheep flocks. These findings are consistent with the known function of ADRB3 in mediating lipolysis and homeostasis in adipose tissues.

Effect of dietary Tartary buckwheat extract supplementation on growth performance, meat quality and antioxidant activity in ewe lambs

The objective of this study was to investigate the effect of dietary Tartary buckwheat extract (TBE) supplementation on animal growth performance, meat quality and antioxidative activity in the Longissimus thoracis et lumborum muscle of lambs. The results showed that dietary TBE increased body weight, average daily gain, carcass weight, dry matter intake, and digestive organ weight. Dietary TBE had no effect on the pH, color, shear force or intramuscular fat of Longissimus muscle examined, whereas the cooking loss was decreased. The total antioxidative capacity and glutathione peroxidase 4 (GPx4) activity of Longissimus muscle were increased in lambs fed TBE. The mRNA contents of superoxide dismutase, catalase, GPx4 and nuclear factor-like-2 factor (Nrf2) did not vary among the groups, and greater protein levels of GPx4 and Nrf2 were observed. Taken together, these results suggest that TBE can be used as a feed ingredient in lamb production to improve its growth performance, and relieve oxidative stress and increase water holding capacity of meat.

The effect of dietary grape pomace supplementation on epididymal sperm quality and testicular antioxidant ability in ram lambs

Wine grape pomace (WGP) contains a rich source of polyphenols that can act as powerful antioxidants. The objective of this study was to investigate the effect of dietary WGP supplementation on antioxidative activity and epididymal sperm quality in rams. The rams were raised either under free-range or pen conditions, and the pen-raised rams were fed a WGP-containing diet (0, 5% and 10% of dry matter basis) for 74 days. An increase in the concentrations of reactive oxygen species (ROS, Pxa0<xa00.05) and malondialdehyde (MDA, Pxa0<xa00.05) were observed in the testes of rams subjected to restraint stress, and dietary WGP supplementation effectively decreased their contents (Pxa0<xa00.05). Restraint stress reduced both weight and volume of testes, and impaired sperm quality. Dietary WGP supplementation increased testes weight, sperm concentration, motility and acrosomal integrity, and decreased sperm deformity in pen-raised animals (Pxa0<xa00.05). The total antioxidative capacity (T-AOC) and catalase activity were decreased in the testes of pen-raised lambs (Pxa0<xa00.05), and T-AOC, catalase, glutathione peroxidase 4 (GPx4) and superoxide dismutase (SOD) activity were increased when rams were fed the WGP-containing diet (Pxa0<xa00.05). With the exception of SOD and GPx4, the mRNA contents of catalase and nuclear factor-like-2 factor (Nrf2) did not vary among the groups, and greater protein levels of SOD, catalase and GPx4 were observed in WGP-treated lambs (Pxa0<xa00.05). Taken together, these results suggest that WGP can be used as a feed ingredient in rams to alleviate restraint induced oxidative stress and improve epididymal sperm quality.

Different dietary energy intake affects skeletal muscle development through an Akt-dependent pathway in Dorper × Small Thin-Tailed crossbred ewe lambs.

The objective of this experiment was to investigate the mechanisms through which different levels of dietary energy affect postnatal skeletal muscle development in ewe lambs. Twelve Dorper × Small Thin-Tailed crossbred ewe lambs (100xa0d of age; 20 ± 0.5xa0kg BW) were selected randomly and divided into 2 groups in a completely randomized design. Animals were offered identical diets at 100% or 65% of ad libitum intake. Lambs were euthanized when BW in the ad libitum group reached 35xa0kg and the semitendinosus muscle was sampled. Final BW and skeletal muscle weight were decreased (P < 0.01) by feed restriction. Both muscle fiber size distribution and myofibril cross-sectional area were altered by feed restriction. Insulin-like growth factor 1 (IGF-1) messenger RNA (mRNA) content was decreased (P < 0.05) when lambs were underfed, whereas no difference for IGF-2 mRNA expression was observed (P > 0.05). Feed restriction altered phosphor-Akt protein abundance (P < 0.01). Moreover, the mammalian target of rapamycin (mTOR) pathway was inhibited by feed restriction, which was associated with decreased phosphor-mTOR, phosphorylated eukaryotic initiation factor 4E binding protein 1 (phosphor-4EBP1), and phosphorylated ribosomal protein S6 kinase (phosphor-S6K). Both mRNA expression of myostatin and its protein content were elevated in feed-restricted ewe lambs (P < 0.05). In addition, mRNA expression of both muscle RING finger 1 and muscle atrophy F-box was increased when ewe lambs were underfed. In summary, feed restriction in young growing ewe lambs attenuates skeletal muscle hypertrophy by inhibiting protein synthesis and increasing protein degradation, which may act through the Akt-dependent pathway.

Intrafollicular expression and potential regulatory role of cocaine- and amphetamine-regulated transcript in the ovine ovary

Follicular growth is regulated by a complex interaction of pituitary gonadotropins with local regulatory molecules. Previous studies demonstrated an important role for cocaine- and amphetamine-regulated transcript (CART) in regulation of granulosa cell estradiol production associated with dominant follicle selection in cattle. However, intraovarian expression and actions of CART in other species, including sheep, are not known. The objective of this study was to investigate the expression of CART in sheep follicles and determine the effects of CART on indices of ovine granulosa cell function linked to follicular development. Results demonstrated the expression of CART messenger RNA and prominent intraovarian localization of CART peptide in granulosa cells of sheep follicles. Granulosa cell CART messenger RNA was lower, but follicular fluid estradiol concentrations were higher in large (>5 mm) follicles vs smaller 3- to 5-mm follicles harvested from sheep ovaries of abattoir origin. CART treatment inhibited follicle stimulating hormone-induced estradiol production by cultured ovine granulosal cells and also blocked the follicle stimulating hormone-induced increase in granulosa cell numbers. Results demonstrate expression of CART in sheep follicular tissues and suggest potential biological actions of CART, which are inhibitory to ovine follicular growth and development.

miR-124-3p affects the formation of intramuscular fat through alterations in branched chain amino acid consumption in sheep

Intramuscular fat is used to determine meat quality in animals; however, factors affecting branched chain amino acid (BCAA) catabolism, which fuels adipogenesis and lipogenesis, remain unclear. To better understand the post-transcriptional influence on BCAA catabolism during adipogenesis, we investigated the role of miR-124-3p. Stromal vascular fraction (SVF) cells were isolated from skeletal muscle of sheep, and induced to differentiate. We determined the roles of miR-124-3p and its predicted target, branched chain keto acid dehydrogenase E1, alpha polypeptide (BCKDHA), in adipogenic differentiation and lipogenesis of SVFs after overexpressing or inhibiting miR-124-3p or BCKDHA, respectively. miR-124-3p altered the luciferase activity of constructs containing 3-UTR of BCKDHA and the formation of lipid droplets, along with the adipogenic markers and BCAA consumption. Besides, the adipogenic performance and BCAA consumption in BCKDHA-overexpressing or knocked-down SVFs and the expression of adipogenic marker genes were altered. We demonstrate that miR-124-3p is an important factor for adipogenesis and provide insights into the formation of intramuscular fat in animals.

Transcriptome analysis of adipose tissues from two fat-tailed sheep breeds reveals key genes involved in fat deposition

BackgroundThe level of fat deposition in carcass is a crucial factor influencing meat quality. Guangling Large-Tailed (GLT) and Small-Tailed Han (STH) sheep are important local Chinese fat-tailed breeds that show distinct patterns of fat depots. To gain a better understanding of fat deposition, transcriptome profiles were determined by RNA-sequencing of perirenal, subcutaneous, and tail fat tissues from both the sheep breeds. The common highly expressed genes (co-genes) in all the six tissues, and the genes that were differentially expressed (DE genes) between these two breeds in the corresponding tissues were analyzed.ResultsApproximately 47 million clean reads were obtained for each sample, and a total of 17,267 genes were annotated. Of the 47 highly expressed co-genes, FABP4, ADIPOQ, FABP5, and CD36 were the four most highly transcribed genes among all the known genes related to adipose deposition. FHC, FHC-pseudogene, and ZC3H10 were also highly expressed genes and could, thus, have roles in fat deposition. A total of 2091, 4233, and 4131 DE genes were identified in the perirenal, subcutaneous, and tail fat tissues between the GLT and STH breeds, respectively. Gene Ontology (GO) analysis showed that some DE genes were associated with adipose metabolism. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed that PPAR signaling pathway and ECM-receptor interaction were specifically enriched. Four genes, namely LOC101102230, PLTP, C1QTNF7, and OLR1 were up-regulated and two genes, SCD and UCP-1, were down-regulated in all the tested tissues of STH. Among the genes involved in ECM–receptor interaction, the genes encoding collagens, laminins, and integrins were quite different depending on the depots or the breeds. In STH, genes such as LAMB3, RELN, TNXB, and ITGA8, were identified to be up regulated and LAMB4 was observed to be down regulated.ConclusionsThis study unravels the complex transcriptome profiles in sheep fat tissues, highlighting the candidate genes involved in fat deposition. Further studies are needed to investigate the roles of the candidate genes in fat deposition and in determining the meat quality of sheep.

MiRNA-seq reveals that miR-124-3p inhibits adipogenic differentiation of the stromal vascular fraction in sheep via targeting C/EBPα

MicroRNAs (miRNAs) are small noncoding 20-25xa0nt RNA molecules that regulate gene expression by posttranscriptional repression of messenger RNA. There have been few investigations on the profiles and functions of miRNAs in ovine subcutaneous fat; their roles in the metabolism and deposition of subcutaneous fat also remain unclear. In this study, small RNA libraries were constructed for 2 important Chinese local sheep breeds, Small-tailed Han Sheep, and Shanxi Meat Sheep Dam Line, and used for high-throughput sequencing. Differentially expressed miRNAs were identified, revealing the effect of miR-124-3p on adipogenic differentiation by targeting C/EBPα. Our results provide both a comprehensive understanding of miRNA expression patterns in sheep subcutaneous fat and an insight into the specific roles of miRNAs in adipogenesis.

Energy requirements for the maintenance and growth of Dorper-Jinzhong crossbred ram lambs

Abstract The sheep industry in China has been rapidly developing in recent years; however, the animals’ nutritional requirements under certain conditions have not been thoroughly defined. The objective of this study was to investigate the energy requirements of both the maintenance and growth of Dorper-Jinzhong crossbred ram lambs. Thirty 1/2 Dorperu2009×u20091/2 Jinzhong crossed F1 ram lambs (35u2009±u20090.5u2009kg of body weight, BW) were randomly selected and divided into five groups in a randomised design for a comparative slaughter trial. The lambs were offered one type of feed at 100%, 65% and 40% of the ad libitum intake. Another 15 lambs were used for the digestibility trial to estimate the metabolisable energy (ME) values of the diet at various feed intake levels. The net energy for maintenance (NEm) and the ME requirement for maintenance (MEm) were 286.68u2009kJ/kg0.75 of SBW and 437.80u2009kJ/kg0.75 of SBW, respectively; the energy efficiency for maintenance (km) was 0.655. The net energy for growth (NEg) values for varying average daily gain (100–350u2009g) in ram lambs grown from 35 to 50u2009kg increased from 1.31 to 5.93u2009MJ/d with an energy efficiency for growth (kg) of 0.457. Our results suggest that the energy requirements of Dorper-Jinzhong crossbred ram lambs are lower than the requirements recommended by the National Research Council (NRC) and Agricultural and Food Research Council (AFRC).