Associations between testicular development and fetal size in the pig

Maternal nutrition and fetal imprinting of the male progeny

The global population as well as the demand for human food is rapidly growing worldwide, which necessitates improvement of efficiency in livestock operations. In this context, environmental factors during fetal and/or neonatal life have been observed to influence normal physical and physiological function of an individual during adulthood, and this phenomenon is called fetal or developmental programming. While numerous studies have reported the impact of maternal factors on development of the female progeny, limited information is available on the potential effects of fetal programming on reproductive function of the male offspring. Therefore, the objective for this review article was to focus on available literature regarding the impact of maternal factors, particularly maternal nutrition, on reproductive system of the male offspring. To this end, we highlighted developmental programming of the male offspring in domestic species (i.e., pig, cow and sheep) as well as laboratory species (i.e., mice and rat) during pregnancy and lactation. In this sense, we pointed out the effects of maternal nutrition on various functions of the male offspring including hypothalamic-pituitary axis, hormonal levels, testicular tissue and semen parameters.

Abundance of selected genes implicated in testicular functions in Camelus dromedarius with high and low epididymal semen quality

Studying testicular genes' expression may give key insights into precise regulation of its functions that influence epididymal sperm quality. The current study aimed to investigate the abundance of candidate genes involved in the regulation of testicular functions specially those regulate sperm function (PLA2G4D, SPP1, and CLUAP1), testicular steroidogenic function (ESR1 and AR), materials transport (AQP12B and LCN15), and defense mechanisms (DEFB110, GPX5, SOCS3, and IL6). Therefore, blood samples and testes with epididymis were collected from mature middle-aged (5-10 years) dromedary camels (n = 45) directly prior and after their slaughtering, respectively, during breeding season. Sera were evaluated for testosterone level and testicular biometry was measured with caliper. The epididymal tail semen was evaluated manually. Samples were distinguished based on testosterone level, testicular biometry, as well as epididymal semen features into high and low fertile groups. Total RNA was isolated from testicular tissues and gene expression was done using Quantitative Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Results revealed that testosterone levels were significantly (P < 0.005) higher in camels with good semen quality than those of low quality. There was a significant (P < 0.0001) increase in testicular weight, length, width, thickness, and volume in high fertile than low fertile camels. PLA2G4D, SPP1, CLUAP1, ESR1, AR, AQP12B, LCN15, DEFB110, GPX5, and SOCS3 genes were upregulated (P < 0.001), and IL6 gene was downregulated (P < 0.01) in the testes of high fertile camels compared to the low fertile one. Thus, it could be concluded that examined genes might be valuable monitors of testicular functional status and fertility in dromedary camels.

Identification and Analysis of Genes Related to Testicular Size in 14-Day-Old Piglets

The RNA-Seq technology was used to screen the key genes that affect the early development of the testes of Duroc × Landrace × Yorkshire piglets, to determine the regulatory pathway and provide reference for subsequent reproductive performance research, breeding, and other production practices. This study selected 14-day-old Duroc × Landrace × Yorkshire piglets as the trial animals. Testes from piglets with similar weights and no pathological changes were divided into small testis (ST) and large testis (LT) groups, and the RNA-Seq screening of differentially expressed genes (DEGs) was performed to find candidate genes and regulatory pathways related to early testicular development. The results show that 570 DEGs were found in the ST and LT groups, with 281 upregulated and 289 downregulated. The DEGs were mainly enriched on 47 gene ontology (GO) functional items. The Kyoto encyclopedia of genes and genotypes (KEGG) enrichment analysis found that there were 44 significantly enriched KEGG signal pathways, and the regulation of testicular development mainly focused on the arachidonic acid metabolism, Wnt signaling pathway and GnRH secretion pathways. The PTGES, SFRP1, SPP1, PLA2G4E, KCNJ5, PTGS2, and HCN1 genes were found to be as closely related to the testicular development of these Duroc × Landrace × Yorkshire piglets, and the differential gene expression was consistent with the real-time quantitative reverse transcription PCR (real-time qRT-PCR) validation results. This study was validated by high-throughput sequencing analysis and real-time qRT-PCR, and showed that the PTGES, SFRP1, SPP1, PLA2G4E, KCNJ5, PTGS2, and HCN1 genes may be involved in the regulation of germ cell development, spermatogenesis and semen traits. These should be further studied as candidate genes for early testicular development and reproductive trait regulation in boars.

Osteopontin Concentration in Prostates Fractions: A Novel Marker of Sperm Quality in Dogs

This study aimed to investigate the relationship between the sperm quality and the osteopontin (OPN) concentration in the prostates of Malakli shepherd dogs. Ejaculates were collected once by digital manipulation from 39 male dogs aged between 2 and 4 years and older. The first and third fractions of the ejaculate were centrifuged at 5000× g for 30 min, and supernatants were stored at -80 °C for further analysis of OPN using a double-antibody sandwich method (SEA899CA, Cloude-Clone Corp, Houston, TX, USA). Meanwhile, the second fractions were evaluated for sperm motility, concentration, viability, and rate of abnormal spermatozoa (head, acrosome, midpiece and tail abnormalities). The average concentration of OPN was 8.7 ± 5.2 ng/mL, and it differed significantly between the 1st 10.4 ± 5.3 ng/mL and 3rd 7.4 ± 5 ng/mL fractions. According to ROC (receiver operating characteristic curve) analysis, the OPN concentration had a better diagnostic ability for sperm motility (p < 0.001) than for the rate of abnormal spermatozoa (p < 0.05). Additionally, the OPN concentration was negatively correlated with poor sperm morphology and motility. In conclusion, the OPN concentration in prostate-derived secretions may be a possible marker of sperm quality in dogs. Further research could explore the involvement of OPN in sperm motility during cryopreservation and in vivo fertility.

Integration of Selection Signatures and Protein Interactions Reveals NR6A1, PAPPA2, and PIK3C2B as the Promising Candidate Genes Underlying the Characteristics of Licha Black Pig

Licha black (LI) pig has the specific characteristics of larger body length and appropriate fat deposition among Chinese indigenous pigs. Body length is one of the external traits that affect production performance, and fat deposition influences meat quality. However, the genetic characteristics of LI pigs have not yet been systematically uncovered. Here, the genomic information from 891 individuals of LI pigs, commercial pigs, and other Chinese indigenous pigs was used to analyze the breed characteristics of the LI pig with runs of homozygosity, haplotype, and FST selection signatures. The results showed the growth traits-related genes (i.e., NR6A1 and PAPPA2) and the fatness traits-related gene (i.e., PIK3C2B) were the promising candidate genes that closely related to the characteristics of LI pigs. In addition, the protein–protein interaction network revealed the potential interactions between the promising candidate genes and the FASN gene. The RNA expression data from FarmGTEx indicated that the RNA expression levels of NR6A1, PAPPA2, PIK3C2B, and FASN were highly correlated in the ileum. This study provides valuable molecular insights into the mechanisms that affect pig body length and fat deposition, which can be used in the further breeding process to improve meat quality and commercial profitability.

A meta-analysis: Effect of androgens on reproduction in sows

INTRODUCTION

The mechanisms by which male hormones affect the development of ovaries and follicles has been studied by injecting exogenous androgens into sows. This may provide a reference for human polycystic ovary syndrome (PCOS), and can also provide guidance for improving the litter size of sows.

METHODS

We present a meta-analysis of studies published in the past 30 years on the effect of androgens on the ovulation rate of sows. A total of 517 papers were analyzed.

RESULTS

The results showed that both testosterone (T) and dihydrotestosterone (DHT) injected into sows were positively related to the ovulation rate. T did not have a relevant effect on swine in vivo blastocyst survival rate. DHT had a negative phase with respect to blastocyst survival rate. Pig T-androgen receiver affinity was higher than the analogous affinity for DHT; this is different in humans. This suggests that sows are not suitable as human PCOS experimental animal models.

DISCUSSION

To improve the litter size of sows, future research should focus on the mixed use of T and DHT, and the timing of use should be consistent with the periodic changes in androgen levels in sows. In addition, the welfare of experimental sows should be considered with reference to the clinical symptoms of PCOS.