Haplotypes of the Ovine Adiponectin Gene and Their Association with Growth and Carcass Traits in New Zealand Romney Lambs

Polymorphism of the ADIPOQ gene and its association with productive traits in Awassi Ewes

BACKGROUND

Adiponectin (ADIPOQ) plays a critical role in energy and lipid metabolism, indicating that adiponectin could affect livestock productivity. There is an association between polymorphisms in the ADIPOQ gene and variations in livestock productive traits. Therefore, this study investigated the relationship between ADIPOQ polymorphism and productive traits in Awassi ewes.

METHODS AND RESULTS

This study included 200 sexually mature ewes, aged 2.5 to 5 years, non-pregnant and not lactating. A phenotypic measurement consisting of live weight and body dimensions, was taken. Samples of blood were taken for extraction of genomic DNA and PCR-SSCP based genotyping, followed by sequencing to confirm variants in amplified fragments. A novel c.198,473,337 C > A SNP was found in exon 1 of the ADIPOQ gene confirming heterogeneity with genotypes AA, CC, and CA. The AA genotype differed significantly (P < 0.05) by comparison with the CA and CC genotypes concerning live body weight and body measurements. An association between productive traits and the c.198,473,337 C > A SNP revealed a significant association of the A allele (odds ratio: 2.22 (95% CI: 0.94-5.30) in the additive genetic model.

CONCLUSION

Sheep with the AA genotype were heavier and had larger body dimensions, implying superior production and reproduction. Further studies are required in other breeds to prove the results.

Novel variants associated with adiponectin-related traits in Awassi ewes

Background

Adipose tissue secretes adiponectin (ADIPOQ), a hormone related to fat oxidation, glucose metabolism, and reproduction. The polymorphism of adiponectin is associated with productive traits in domestic animals. Thus, this study investigated the association of adiponectin gene polymorphism with lipid profile and reproductive hormones in Awassi ewe. In this study, 200 ewes between the ages of 2.5 and 5 years, neither pregnant nor lactating, were included. To determine the lipid profile and reproductive hormones, sera were separated from the blood. DNA extraction, genotyping, and sequencing reactions were used to verify the variants in the amplified fragments (exon 1).

Results

Three genotypes, CC, CA, and AA, were identified from 368 bp amplicons (exon 1). A sequencing reaction revealed a novel mutation, c.198473337C > A, in the CA genotype. The results revealed significant differences (P ≤ 0.05) in cholesterol and HDL levels in the AA genotype than CC and CA genotypes. The AA genotype had higher estradiol and progesterone levels (50.52 ± 0.64) (pg/ml) and (7.10 ± 0.04) (ng/ml), respectively, than those with the CC and CA genotypes.

Conclusions

These results conclude that the ADIPOQ gene affects lipid profiles and sex hormone levels in Awassi sheep. Choosing sheep that are polymorphic for the ADIPOQ gene should be a future study, as this gene could be linked to high prolificacy.

Co-expression of candidate genes regulating growth performance and carcass traits of Barki lambs in Egypt

Sheep are considered one of the main sources of animal protein in Egypt and the producers of sheep mutton eagers to find biological criteria for selecting fast-growing lambs that reach market weight early. Therefore, the present study aimed to find a link between the expression profile of selected candidate genes with growth performance and carcass traits of Barki lambs. Thirty-eight Barki lambs were kept and fed individually after weaning till 12 months of age and were divided into 3 groups according to growth performance (fast, intermediate, and slow-growing). Three samples were taken from different body tissues (eye muscle, liver, and fat tail) of each group, directly during slaughtering and stored at − 80 °C until RNA isolation. Real-time PCR was used to profile selected candidate genes (RPL7, CTP1, FABP4, ADIPOQ, and CAPN3) and GAPDH was used as a housekeeping gene. The results indicated that the final body weight was significantly (P ≤ 0.05) greater in the fast (49.9 kg) and intermediate (40.7 kg) compared to slow-growing animals (30.8 kg). The hot carcass weight was heavier (P ≤ 0.05) in the fast and intermediate-growing (24.57 and 19.07 kg) than slow-growing lambs (15.10 kg). The blood profiles of T3 and T4 hormones in addition to other parameters such as total protein, total lipids, and calcium level showed no clear variations among different experimental groups. At the molecular level, our data demonstrated upregulation of genes involved in protein biosynthesis (RPL7), fatty acid oxidation (CPT1), and lipolysis (FABP4) in the fast and intermediate-growing lambs in all studied tissues which facilitate protein accretion, energy expenditure, and fatty acid partitioning required for muscle building up. Moreover, the expression profile of the gene involved in muscle development (CAPN3) was increased in fast and intermediate-growing compared to slow-growing lambs in order to support muscle proper development. On the other hand, a candidate gene involved in lipogenesis (ADIPOQ) was expressed similarly in fat and liver tissues; however, its expression was increased in muscles of fast and intermediate-growing lambs compared to slow-growing animals. In conclusion, the current study indicated that the expression profile of genes involved in metabolic activities of liver, muscle, and adipose tissue is linked with the growth performance of lambs although no variations were detected in blood parameters. This provides an evidence for the importance of co-expression of these genes in body tissues to determine the final body weight and carcass characteristics of Barki sheep.

Co-inherited novel SNPs of the LIPE gene associated with increased carcass dressing and decreased fat-tail weight in Awassi breed

The lipase E hormone-sensitive (LIPE) enzyme is one of the lipolytic enzymes, and it plays a key role in the regulation of adipose tissue deposition. This study was conducted to investigate the possible association between the LIPE gene variations and the main body weight measurements in Awassi sheep. A total of 160 of sexually mature Awassi rams (Ovis aries) that aged between 2 and 3 years were included in the present study. Genomic DNA was extracted and two specific PCR amplicons were designed to amplify two coding regions within the LIPE gene. Genotyping experiments were performed using polymerase chain reaction-single-strand conformational polymorphism (PCR-SSCP). Two different SSCP banding patterns were identified, CC and CD in exon 2, and AA and AT in exon 9. Five novel single-nucleotide polymorphisms (SNPs) were detected by sequencing, namely g.151C > A and g.198C > T in exon 2, and g.213G > C, g.226G > T, and g.232A > C in exon 9. Haplotype block analysis showed strong linkage disequilibrium values between the two SNPs in exon 2 and the three SNPs in exon 9. Association analysis of haplotypes with carcass traits demonstrated a significantly higher dressing percentage (P < 0.05) and lower fat tail weight (FTW) in CACT and GCGTAC haplotypes made these haplotypes more favorable for human consumption. The current research is the first one to report a tight association between the LIPE genetic polymorphism and the dressing percentage and FTW traits, suggesting a pivotal role played by these co-inherited SNPs in the metabolism of carcass traits in sheep.

NK, S. S, Fairoze MN, Kaur M, Sharma A, Girdhar Y, M. SR, Devatkal SK, Ahlawat S, Vijh RK, S. MS. Transcriptome profiling of longissimus thoracis muscles identifies highly connected differentially expressed genes in meat type sheep of India

This study describes the muscle transcriptome profile of Bandur breed, a consumer favoured, meat type sheep of India. The transcriptome was compared to the less desirable, unregistered local sheep population, in order to understand the molecular factors related to muscle traits in Indian sheep breeds. Bandur sheep have tender muscles and higher backfat thickness than local sheep. The longissimus thoracis transcriptome profiles of Bandur and local sheep were obtained using RNA sequencing (RNA Seq). The animals were male, non-castrated, with uniform age and reared under similar environment, as well as management conditions. We could identify 568 significantly up-regulated and 538 significantly down-regulated genes in Bandur sheep (p≤0.05). Among these, 181 up-regulated and 142 down-regulated genes in Bandur sheep, with a fold change ≥1.5, were considered for further analysis. Significant Gene Ontology terms for the up-regulated dataset in Bandur sheep included transporter activity, substrate specific transmembrane, lipid and fatty acid binding. The down-regulated activities in Bandur sheep were mainly related to RNA degradation, regulation of ERK1 and ERK2 cascades and innate immune response. The MAPK signaling pathway, Adipocytokine signaling pathway and PPAR signaling pathway were enriched for Bandur sheep. The highly connected genes identified by network analysis were CNOT2, CNOT6, HSPB1, HSPA6, MAP3K14 and PPARD, which may be important regulators of energy metabolism, cellular stress and fatty acid metabolism in the skeletal muscles. These key genes affect the CCR4-NOT complex, PPAR and MAPK signaling pathways. The highly connected genes identified in this study, form interesting candidates for further research on muscle traits in Bandur sheep.