Efficient use of feed resources is a challenge in the pork industry because the largest variability in expenditure is attributed to the cost of fodder. Efficiency of feeding is directly related to feeding behavior. In order to identify genomic regions controlling feeding behavior and eating efficiency traits, 338 Duroc boars were used in this study. The Illumina Porcine SNP60K BeadChip was used for genotyping. Data pertaining to individual daily feed intake (DFI), total daily time spent in feeder (TPD), number of daily visits to feeder (NVD), average duration of each visit (TPV), mean feed intake per visit (FPV), mean feed intake rate (FR), and feed conversion ratio (FCR) were collected for these pigs. Despite the limited sample size, the genome-wide association study was acceptable to detect candidate regions association with feeding behavior and eating efficiency traits in pigs. We detected three genome-wide (P < 1.40E-06) and 11 suggestive (P < 2.79E-05) single nucleotide polymorphism (SNP)-trait associations. Six SNPs were located in genomic regions where quantitative trait loci (QTLs) have previously been reported for feeding behavior and eating efficiency traits in pigs. Five candidate genes (SERPINA3, MYC, LEF1, PITX2, and MAP3K14) with biochemical and physiological roles that were relevant to feeding behavior and eating efficiency were discovered proximal to significant or suggestive markers. Gene ontology analysis indicated that most of the candidate genes were involved in the development of the hypothalamus (GO:0021854, P < 0.0398). Our results provide new insights into the genetic basis of feeding behavior and eating efficiency in pigs. Furthermore, some significant SNPs identified in this study could be incorporated into artificial selection programs for Duroc-related pigs to select for increased feeding efficiency.
Real time RT-PCR was applied to study the developmental patterns of leptin and leptin receptor gene mRNA expression at the ages of 1,27,90,150 and 180 days after born(DAB) in subcutaneous fat and hypothalamus of Lantang and Landrace pigs.The results showed that:(1) in subcutaneous fat,Lantang had the highest leptin mRNA level at 180 DAB.Leptin mRNA at all ages in lantang was higher than that in landrace,except at 1 DAB.Leptin mRNA was significantly higher in Lantang pig than that in landrace pig at 180 DAB.Leptin mRNA had no significant difference among landrace pigs at all ages.(2) In hypothalamus,leptin receptor mRNA was highest at 180 DAB for both the two breeds,and it had significantly higher than that at other ages in lantang,and at 1 and 27 d in landrace.Two breeds at 1 d had apparent differed.(3) Lantang pigs at all ages had higher serum leptin level than landrace.Two breeds at 150 d were the highest compared with other ages.Lantang pigs at 150 day had significantly higher than at ages of 27 and 180 day.No significant changes were seen in all ages in landrace.
Enucleation is a crucial procedure for mammalian somatic cell nuclear transfer (SCNT), especially for domestic animal cloning. Oocytes of domestic animals such as pigs and cattle contain dark lipid droplets that hinder localization and removal of the nucleus. Using an oocyte enucleation technique that can obtain a high enucleation rate but has minimal negative effects on the reprogramming potential of oocyte for cloning is beneficial for enhancing the outcome of SCNT. In this study, we compared the pig cloning efficiency resulting from blind aspiration-based (BA-B) enucleation and spindle imaging system-assisted (SIS-A) enucleation, and compared the pig SCNT success rate associated with BA-B enucleation and blind aspiration plus post-enucleation staining-based (BAPPS-B) enucleation. SIS-A enucleation achieved a significantly higher oocyte enucleation success rate and tended to obtain a higher in vivo full term development rate of SCNT embryos than BA-B enucleation. BAPPS-B enucleation also obtained significantly higher in vitro as well as in vivo full term development efficiency of cloned porcine embryos than BA-B enucleation. These data indicate that SIS-A and BAPPS-B enucleation are better approaches for pig SCNT than BA-B enucleation.
The full length cDNA of pGhrelin was obtained by RT-PCR and was subsequently inserted into pcDNA3.1(+) to construct eukaryotic expression vector pcDNA-pGhl.The growth promoting efficacies of pcDNA-pGhl were examined by weight gains in rats and secretions of GH and SS in rabbits.Growth and feed efficiency were both improved after the injection of pcDNA-pGhl,that by day 6 post-injection the body weight in the treatment rats was 10.6% higher(P0.05),and the feed/gain ratio was also more significantly reduced by 10%(P0.01) than in the control rats.Injection of 600 μg pcDNA-sGhl plasmid into rabbit slightly increased blood GH concentrations by 35% compared with the controls at 2 weeks post-injection(P=0.108 6),while at the same time increased somatostatin concentration which by day 35 was significantly higher(P0.05) than in the non-treated control rabbits.These results demonstrated that eukaryotic expression plasmid of Ghrelin stimulates growth by stimulation of GH secretions,but the growth promoting efficacy was short lived by the simultaneous stimulation of somatostatin secretion.
Litter size is a crucial quantitative trait in animals, closely linked to follicular development. Circular RNA (circRNA), a type of single-stranded closed-loop endogenous RNA with stable expression, plays pivotal roles in various biological processes, yet its function in goat follicular development remains unclear. In this study, we collected large (follicle diameter > 3 mm) and small (1 mm < follicle diameter < 3 mm) follicles from black goats in the Chuanzhong region for circRNA sequencing, with the aim of elucidating the functional circRNAs that influence follicle development in goats. Differential analysis revealed that 17 circRNAs were upregulated in large follicles, and 28 circRNAs were upregulated in small follicles. Functional enrichment analysis revealed significant enrichment of pathways related to reproduction, including cellular response to follicle-stimulating hormone stimulus, the PI3K-Akt signaling pathway, the MAPK signaling pathway, and the Notch signaling pathway. Based on the ceRNA mechanism, 45 differentially expressed circRNAs were found to target and bind a total of 418 miRNAs, and an intercalation network including miR-324-3p (circRNA2497, circRNA5650), miR-202-5p (circRNA3333, circRNA5501), and miR-493-3p (circRNA4995, circRNA5508) was constructed. In addition, conservation analysis revealed that 2,239 circRNAs were conserved between goats and humans. Prediction of translation potential revealed that 154 circRNAs may potentially utilize both N6-methyladenosine (m6A) and internal ribosome entry site (IRES) translation mechanisms. Furthermore, the differential expression and circularization cleavage sites of five circRNAs were validated through RT-qPCR and DNA sequencing. Our study constructed a circRNA map in goat follicle development, offering a theoretical foundation for enhancing goat reproductive performance.
Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) is a precise genome manipulating tool that can produce targeted gene mutations in various cells and organisms. Although CRISPR/Cas9 can efficiently generate gene knockout, the gene knock-in (KI) efficiency mediated by homology-directed repair remains low, especially for large fragment integration. In this study, we established an efficient method for the CRISPR/Cas9-mediated integration of large transgene cassette, which carries salivary gland-expressed multiple digestion enzymes (≈ 20 kbp) in CEP112 locus in pig fetal fibroblasts (PFFs). Our results showed that using an optimal homology donor with a short and a long arm yielded the best CRISPR/Cas9-mediated KI efficiency in CEP112 locus, and the targeting efficiency in CEP112 locus was higher than in ROSA26 locus. The CEP112 KI cell lines were used as nuclear donors for somatic cell nuclear transfer to create genetically modified pigs. We found that KI pig (705) successfully expressed three microbial enzymes (β-glucanase, xylanase, and phytase) in salivary gland. This finding suggested that the CEP112 locus supports exogenous gene expression by a tissue-specific promoter. In summary, we successfully targeted CEP112 locus in pigs by using our optimal homology arm system and established a modified pig model for foreign digestion enzyme expression in the saliva.
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