Age related changes in testicular histomorphometry and spermatogenic activity of bulls

The aim of the present study was to evaluate age related changes in testicular histomorphometry and spermatogenic activity of bulls during their sexual development. A total of 36 bulls were selected and divided into four groups (n=9 in each) according to their age. Bulls included in Groups I, II, III and IV were 10, 12, 14 and 16 months old respectively. Left testes of bulls were subjected to histomorphometry after slaughter. Statistical analysis revealed that the secondary spermatocytes, round and elongated spermatids increased significantly (P˂0.05) with the age of bulls. Likewise, both sertoli and leydig cell numbers increased significantly (P˂0.05) with the age of bulls. However, the number of spermatogonia and primary spermatocytes did not change (P>0.05) due to age. The mean tubular diameter increased from 200.70±5.45 μm (10 months of age) to 227.30±9.16 μm (16 months of age) and the total volume of seminiferous tubule per testis from 69.63±1.50 % (10 months of age) to 84.64±2.53 % (16 months of age). A positive linear relationship (P<0.05) was found between meiotic index (Y) and the age (X, in month), which was characterized by the equation 0.048X+3.135 and a coefficient of correlation (R) of 0.396. The correlation between age and sertoli cell efficiency was 0.482 with a regression equation Y= 0.141X+7.696. It is concluded that histomorphometric parameters of the bulls’ testes and spermatogenic activity are correlated with the age, so these parameters provide a reliable tool for the assessment of the reproductive state and sperm production capacity of a bull in a breeding program.

Inhibiting Kiss1 Neurons with Kappa Opioid Receptor Agonists to Treat Polycystic Ovary Syndrome and Vasomotor Symptoms

Context Recent evidence suggests that vasomotor symptoms (VMS) or hot flashes in the postmenopausal reproductive state and polycystic ovary syndrome (PCOS) in the premenopausal reproductive state emanate from the hyperactivity of Kiss1 neurons in the hypothalamic infundibular/arcuate nucleus (KNDy neurons). Objective We demonstrate in 2 murine models simulating menopause and PCOS that a peripherally-restricted kappa receptor agonist (PRKA) inhibits hyperactive KNDy neurons (accessible from outside the blood brain barrier) and impedes their down-stream effects. Design Case/control. Setting Academic medical center. Participants Mice. Interventions Administration of peripherally-restricted kappa receptor agonists and frequent blood sampling to determine hormone release, and body temperature. Main Outcome Measures LH pulse parameters and body temperature. Results First, chronic administration of a PRKA to OVX mice with experimentally-induced hyperactivity of KNDy neurons reduces the animals’ elevated body temperature, mean plasma LH level, and mean peak LH per pulse. Second, chronic administration of a PRKA to a murine model of PCOS, having elevated plasma testosterone levels and irregular ovarian cycles, suppresses circulating levels of LH and testosterone and restores normal ovarian cyclicity. Conclusion The inhibition of Kiss1 neuronal activity by activation of kappa receptors shows promise as a novel therapeutic approach to treat both VMS and PCOS in humans.

Activity budget and gut microbiome structure across reproductive states in wild, female capuchin monkeys

Energy demands associated with pregnancy and lactation have been a significant force in mammalian evolution. To mitigate increased energy costs associated with reproduction, female mammals have evolved multiple behavioural and physiological responses. Some species alter activity budget to conserve energy during pregnancy and lactation, while others experience changes in metabolic rate and fat deposition. Previous studies suggest that restructuring of gut microbiota with shifting reproductive states may help females increase energy harvest from foods, especially during pregnancy, while others have found little change in response to pregnancy or lactation. Here, we combined a robust set of >10,000 individual behavioural scans with >300 fecal samples collected longitudinally across multiple years from 33 known white-faced capuchin monkey females to examine the relationships among behaviour, gut microbiota composition, and reproductive state. We used a 16S-based amplicon sequencing approach and the DADA2 pipeline to anlayse gut microbiota diversity and putative functions. We found that reproductive state explained some variation in activity budget, but that overall resting behaviour was relatively stable across the reproductive cycle. We found evidence for increases in biotin synthesis pathways among microbes in lactating females, and that the alpha diversity of gut microbial bacteria was higher in pregnant females. Otherwise, the gut microbiota community structure and estimated functional pathways were not significantly different between reproductive states. These results suggest that capuchins in our population may have limited ability to mitigate energy costs through behaviour and microbiota and/or that ecological factors, including food availability and temperature may constrain behavioural flexibility and/or gut microbial plasticity. These data contribute to a broader understanding of plasticity and constraint at multiple levels in response to the physiological shifts caused by mammalian reproduction.

A distributed dopamine-gated circuit underpins reproductive state-dependent behavior in Drosophila females

Motherhood induces a drastic, sometimes long-lasting, change in internal state and behavior in most female animals. Here, we show that a mating-induced increase in olfactory attraction of female Drosophila flies to nutrients relies on interconnected neural pathways in the two higher olfactory brain regions, the lateral horn (LH) and the mushroom body (MB). Using whole brain calcium imaging, we find that mating does not induce a global change in the activity of the whole brain nor of entire brain regions, suggesting specific neuronal or network changes in the olfactory system. Systematic behavioral screening and electron microscopy (EM) connectomics identify two types of LH output neurons required for the attraction of females to polyamines -one of them previously implicated in the processing of male pheromones. In addition, we characterize multiple MB pathways capable of inducing or suppressing polyamine attraction, with synaptic connections to the identified LH neurons and a prominent role for the β′1 compartment. Moreover, β′1 dopaminergic neurons are modulated by mating and are sufficient to replace mating experience in virgins inducing the lasting behavioral switch in female preference. Taken together, our data in the fly suggests that reproductive state-dependent expression of female choice behavior is regulated by a dopamine-gated distributed learning circuit comprising both higher olfactory brain centers.

Determining the Effect of Age on the Reproductive and Stress Physiology of Octopus Bimaculoides Using Dermal Hormones

Our goal was to validate the use of dermal swabs to evaluate both reproductive and stress physiology in the California two-spot octopus, Octopus bimaculoides. Our objectives were to: 1. use a biological stressor to validate glucocorticoid analysis; 2. compare the concentration of reproductive hormones (estrogen and progesterone in females; testosterone in males) of reproductive (N = 4) and senescent (N = 8) individuals to determine the effect of age on hormonal patterns; and 3. determine the relationship between glucocorticoid and reproductive hormone production. For the stress test, individuals were first swabbed and then chased around the aquarium with a net for five minutes. Afterwards, individuals were swabbed for 2 hours at 15-minute intervals to compare to a pre-stress test swab. Reproductive individuals responded to the stressor with a 2-fold peak of cortisol at 15 and 90 minutes. Six of eight senescent individuals did not produce a 2-fold increase in cortisol. Reproductive females had significantly higher sex hormone concentrations (progesterone, estrogen, and testosterone) compared to senescent females. Reproductive males also had significantly higher levels of testosterone compared to their senescent counterparts. After the stressor, only reproductive males produced a 2-fold increase in testosterone concentrations, while sex hormones in females showed no change. Dermal swabs provide an effective and non-invasive means for evaluating octopus hormones, which can provide indicators of both reproductive state and perceptions of acute stressors.

Ontogeny of Inner Ear Saccular Development in the Plainfin Midshipman (Porichthys notatus)

The auditory system of the plainfin midshipman fish (<i>Porichthys notatus</i>) is an important sensory system used to detect and encode biologically relevant acoustic stimuli important for survival and reproduction including social acoustic signals used for intraspecific communication. Previous work showed that hair cell (HC) density in the midshipman saccule increased seasonally with reproductive state and was concurrent with enhanced auditory saccular sensitivity in both females and type I males. Although reproductive state-dependent changes in HC density have been well characterized in the adult midshipman saccule, less is known about how the saccule changes during ontogeny. Here, we examined the ontogenetic development of the saccule in four relative sizes of midshipman (larvae, small juveniles, large juveniles, and nonreproductive adults) to determine whether the density, total number, and orientation patterns of saccular HCs change during ontogeny. In addition, we also examined whether the total number of HCs in the saccule differ from that of the utricle and lagena in nonreproductive adults. We found that HC density varied across developmental stage. The ontogenetic reduction in HC density was concurrent with an ontogenetic increase in macula area. The orientation pattern of saccular HCs was similar to the standard pattern previously described in other teleost fishes, and this pattern of HC orientation was retained during ontogeny. Lastly, the estimated number of saccular HCs increased with developmental stage from the smallest larvae (2,336 HCs) to the largest nonreproductive adult (145,717 HCs), and in nonreproductive adults estimated HC numbers were highest in the saccule (mean ± SD = 28,479 ± 4,809 HCs), intermediate in the utricle (mean ± SD = 11,008 ± 1,619 HCs) and lowest in the lagena (mean ± SD = 4,560 ± 769 HCs).

Gonadal morphology, histology and spermatogenesis of striped piggy fish, Pomadasys stridens (Forsskal, 1775) (Family: Pomadasyidae) from Karachi coast, Pakistan.

A study was conducted on the histological structure, morphology of gonads and spermatogenesis of testes of the striped piggy fish, Pomadasys stridens from Karachi coast of Pakistan. The reproductive biology of grunt fishes, and the Pomadasys stridens in particular, is not well understood with respect to functional morphology and histology of the gonads in relation to sexual maturity. In the course of an investigation of the genetic variability of Pomadasys stridens, differences in morphology were observed between the right and left gonad of male and female fish and the size of the fat body associated with the gonads. Histological examinations were made to determine the relationship between these morphological differences and the reproductive state of the gonads. Findings made from this paper are gonad morphology, histology, and spermatogenesis and relate them to the reproductive biology of this species.

Season and habitat affect diversity, abundance and reproductive state of small mammals near Lake Abaya, Ethiopia

This study investigated the spatio-temporal association of small mammals in human-modified habitats. Small mammals were sampled using Sherman traps along 200 m transects (with one trap at every 10 m interval) in each of four habitats (cropland, forest patch, scrubland and wetland) replicated twice. Additional trapping was carried out in rural settlements comprising of eight homesteads, with five traps per homestead. Trapping was conducted in three sessions during the agricultural seasons: rainy (October), off-rain (December) and dry (February) over two years (2018 and 2019). In each session, trapping was carried out for three consecutive nights. A total of 497 small mammals belonging to 12 species from four families (Soricidae, Macroscelididae, Gliridae and Muridae) were captured. Murine rodents accounted for 99.4% of the animals with Mastomys erythroleucus (58%) being the dominant species. The scrubland had the highest small mammal species diversity while the cropland had the lowest. M. erythroleucus was not strongly associated with any spatio-temporal parameter and scored majority of seasonally reproducing individuals in the cropland, signifying its pest importance. Though disconnected from protected areas, habitats such as the scrubland harbor diverse small mammal species (including a vulnerable-endemic species, Grammomys minnae), suggesting the habitats’ significance for ecosystem functioning and conservation.