Olfactory stimulation or inhibition of sexual behavior of stallions in non-breeding season

Olfactory Stimulation as Environmental Enrichment for Domestic Horses-A Review

Horses constantly face several challenges inherent to the domestic environment, and it is common for the expression of their natural behavior to be drastically limited. Environmental enrichment has been suggested as an alternative to improve the captive situation of domestic horses. Among the recently proposed enrichment strategies, olfactory stimulation has emerged as a method for improving several aspects related to animal behavior. Olfaction is a sensory modality that plays a significant role in the expression of equine behavior, and in recent years, studies have shown that olfactory stimulation can influence the physiological and behavioral parameters of horses. This review provides current information on the anatomical particularities of the equine olfactory system, presents the physiological mechanisms involved in the odor detection process, and demonstrates how stress can interfere with this process. Finally, the use of olfactory stimulation as an environmental enrichment for domestic horses (Equus ferus caballus) is explored. The need for new studies that answer pertinent questions related to this topic is discussed throughout the manuscript.

Immune profiles of male giant panda (Ailuropoda melanoleuca) during the breeding season

Background

The giant panda (Ailuropoda melanoleuca) is a threatened endemic Chinese species and a flagship species of national and global conservation concern. Life history theory proposes that reproduction and immunity can be mutually constraining and interrelated. Knowledge of immunity changes of male giant pandas during the breeding season is limited.

Results

Here, we researched peripheral blood gene expression profiles associated with immunity. Thirteen captive giant pandas, ranging from 9 to 11 years old, were divided into two groups based on their reproductive status. We identified 318 up-regulated DEGs and 43 down-regulated DEGs, which were enriched in 87 GO terms and 6 KEGG pathways. Additionally, we obtained 45 immune-related genes with altered expression, mostly up-regulated, and identified four hub genes HSPA4, SUGT1, SOD1, and IL1B in PPI analysis. These 45 genes were related to pattern recognition receptors, autophagy, peroxisome, proteasome, natural killer cell, antigen processing and presentation. SUGT1 and IL1B were related to pattern recognition receptors. HSP90AA1 was the most up-regulated gene and is a member of heat shock protein 90 family. HSP90 contributes to the translocation of extracellular antigen. KLRD1 encodes CD94, whose complex is an inhibitor of the cytotoxic activity of NK cells, was down-regulated. IGIP, which has the capability of inducing IgA production by B cells, was down-regulated, suggesting low concentration of IgA in male giant pandas. Our results suggest that most immune-related genes were up-regulated and more related to innate immune than adaptive immune.

Conclusions

Our results indicated that breeding male giant pandas presented an immunoenhancement in innate immunity, enhanced antigen presentation and processing in cellular immunity compared to non-breeding males. The humoral immunity of male giant pandas may show a tendency to decrease during the breeding season. This study will provide a foundation for further studies of immunity and reproduction in male giant pandas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07456-x.

α-Pinene odor exposure enhances heat stress tolerance through Daf-16 in Caenorhabditis elegans

Aromatherapy has been widely used as complementary and alternative medicine to reduce pain and induce sleep. However, the scientific evidence regarding the biological effects of odor is scarce and the underlying molecular mechanisms have not been clarified. We treated worms with contactless S-(-)- and R-(+)-α-pinene and analyzed heat stress tolerance. Odor stimulation induced motility recovery after incubation at 35 °C for 4 h. This increase in heat stress tolerance was not present in odr-3 mutants and daf-16 mutants. S-(-)- and R-(+)-α-pinene expanded health span and increased fat accumulation. Moreover, S-(-)- and R-(+)-α-pinene modulated the expression of 84 and 54 genes, respectively. These results show that α-pinene odor stimulation is related to stress tolerance, lipid metabolism, and health span via some specific signaling pathways. This study may provide a potential target for antiaging and disease prevention.

Evidence of distinct gene functional patterns in GC-poor and GC-rich isochores in Bos taurus

Vertebrate genomes are mosaics of megabase-size DNA segments with a fairly homogeneous base composition, called isochores. They are divided into five families characterized by different guanine-cytosine (GC) levels and linked to several functional and structural properties. The increased availability of fully sequenced genomes allows the investigation of isochores in several species, assessing their level of conservation across vertebrate genomes. In this work, we characterized the isochores in Bos taurus using the ARS-UCD1.2 genome version. The comparison of our results with the well-studied human isochores and those of other mammals revealed a large conservation in isochore families, in number, average GC levels and gene density. Exceptions to the established increase in gene density with the increase in isochores (GC%) were observed for the following gene biotypes: tRNA, small nuclear RNA, small nucleolar RNA and pseudogenes that have their maximum number in H2 and H1 isochores. Subsequently, we assessed the ontology of all gene biotypes looking for functional classes that are statistically over- or under-represented in each isochore. Receptor activity and sensory perception pathways were significantly over-represented in L1 and L2 (GC-poor) isochores. This was also validated for the horse genome. Our analysis of housekeeping genes confirmed a preferential localization in GC-rich isochores, as reported in other species. Finally, we assessed the SNP distribution of a bovine high-density SNP chip across the isochores, finding a higher density in the GC-rich families, reflecting a potential bias in the chip, widely used for genetic selection and biodiversity studies.

Reproductive parameters of donkey jacks undergoing puberty

In male donkeys, puberty and the related events have been poorly characterized. The aim of this study was to evaluate the age at which male donkeys reach puberty, and characterize age associated changes in testicular size, testicular blood flow, serum testosterone concentration and semen quality. Every two months, starting at 6 months and finishing at 24 months of age, five male donkeys born in May to July were subjected to B-mode ultrasound examination to assess testicular size and scrotum content and blood serum sampling for testosterone concentration. From the age of 8 months, pulsed Doppler was employed to evaluate blood flow in the testicular artery. Testosterone serum concentration was evaluated via RIA. From the age of 12 months, monthly semen collections were attempted and semen was evaluated for sperm number, motility and morphology. Onset of puberty was defined as the first ejaculate containing ≥50 × 10⁶ spermatozoa with ≥10% total motility. One of the donkeys was excluded from the statistical analyses due to a hydrocele presented during the study. Testes width was affected by age (P < 0.0001) and after an initial plateau increased linearly from 10 months of age. Pulsatility and resistivity indexes were also affected by age (P < 0.01), being significantly higher at 14 months than at 24 months. Testosterone serum concentration was affected by age (P < 0.0001) and was significantly lower at 6 months (0.1 ng/ml) compared to 22-24 months (≥0.8 ng/ml). Spermatozoa appeared in the ejaculate at a mean age of 18.7 months and puberty was attained between 19 and 20 months of age (mean: 19.5 months), between January and February. In conclusion, late spring born Amiata donkey colts reached puberty at 19-20 months of age. Puberty was accompanied by changes in testicular size, testicular blood flow and serum testosterone concentration.