Anti-Müllerian hormone (AMH) is a dimeric glycoprotein belonging to the superfamily of the transforming growth factor-β. Due to the discovery of AMH functions, relative to the ovarian function, it is being postulated as being a highly important marker in studies on mammalian reproduction. Therefore, the objective of this review was to describe the role of this hormone in different reproductive aspects of female mammals, taking women, cows, and mares as reference species. The relationship between ovarian reserve and AMH was analysed, and it has been verified that there is a relationship between the latter, the antral follicle count, and the number of primary follicles. AMH concentration has been associated with parameters like the age of the individual, fertility, superovulation treatments and embryo production, and to the reproductive hormone concentration. Also, an association between AMH and female reproduction system diseases, and the fact that AMH is a heritable feature in the cow have also been proven. Recent studies have analysed the role of AMH receptor type 2 since it appears that, together with gonadotropin-releasing hormone, it controls the secretion of gonadotropins. Despite the considerable amount of bibliography on AMH, more studies are needed to complete the information that we have on it, in order to reveal the unknown elements in its action mechanisms.

Since the 1980s, research has linked environmental factors to adult-onset diseases. The DOHaD theory suggests that exposures during development can permanently affect organ function, predisposing individuals to adult diseases. Studies indicate that protein restriction or a high-fat diet (HFD) during this phase impacts adult metabolism since programmed dysfunctions may depend on changes established during puberty, such as the reproductive system. However, there are no studies on the impact of low-protein (LP) or HFD on male testicles during this phase. For this, Male Wistar rats were categorized into three dietary groups: LP (isocaloric low-protein pelletized); HFD; and Control (balanced commercial) until PND 60. This study was approved by the CEUA-UEM. On postnatal day 61, the animals were euthanized for histopathological, sperm count, and oxidative stress assessments in the testis and epididymis. Statistical analyses were conducted following established ethical principles in animal research. The research revealed significant alterations in daily sperm production and transit through the epididymis. Sperm morphology was affected in the experimental groups. Mitochondrial activity increased in the HFD group. Testicular and epididymal histopathology, seminiferous tubule diameter, and germinal epithelium height, as well as the number of Sertoli and Leydig cells, remained unchanged. Stereological analysis revealed tissue remodeling in the epididymis, particularly in the LP group. LP group showed an increase in lipid peroxidation in the oxidative damage test. In conclusion, low-protein and HFD during peripubertal age did not affect postnatal testicular development in rats. However, they impacted sperm quality, potentially affecting fertility and male reproductive system development.

The explosive increase in life expectancy over the 20th century led to the formulation of multiple gerontological theories. Of these, it is the evolutionary theories of senescence that enjoy the greatest theoretical and empirical support today. It is striking that these models put reproduction at the center of their postulates, an emphasis shared with the Aristotelian and Thomistic doctrines of the living being; this meeting point inspires our model. In particular, we hypothesize that the corporeal living being, precisely because of its mortality, can only fulfill the universal vocation to similitudo Dei through the generation of another living being of the same species. Once this purpose is fulfilled, its biological organization – understood here as a minimal entitative disposition that allows the actualization of matter by substantial form – decays and is exposed to random damage, as predicted by evolutionary models. This gradual decline is what is known as senescence. Such an approach opens up the possibility of addressing aging positively, with an emphasis on organizational prolongation resulting in a healthier old age. At the same time, such a perspective could illuminate our current understanding of biological organization and the pathologies that affect it.

The successful survival of crocodilian hatchlings is largely dependent upon nest care by females. Nonetheless, it is crucial to understand how environmental degradation affects nest site selection and parental behaviour in female crocodilians. Therefore, our objective was to evaluate the relationship between anthropogenic disturbances and nesting behaviour in free-living broad-snouted caiman (Caiman latirostris). We compared nests in a disturbed and a non-disturbed area, and anticipated differences in nest density, hatching success, female size, egg number and biomass, and parental care behaviour. We monitored 44 nests over four years in Brazil, covering 58.25 km, in a disturbed area (n = 8) and a non-disturbed area (n = 36). According to our findings, nest density was significantly higher in the non-disturbed area (1.31 nests per linear km) compared to the disturbed area (0.25 nests per linear km). However, there was a significantly higher frequency of parental care behaviour (86%) in the disturbed area compared to the non-disturbed area (34%). The other factors studied showed no statistical difference between the two areas. The results indicate that females prefer to nest in healthier, preserved environments, away from anthropogenic disturbances. Yet, presumably at the cost of extra energy expenditure, increased parental care appears to buffer against a reduction in hatching success. Despite the behavioural buffer, the clear preference for non-disturbed nesting and nursery locations underscores the need to identify and protect the remaining non-disturbed areas inhabited by these animals. Our findings suggest that these measures should positively impact the welfare and protection of C. latirostris and other crocodilian species.

Gecarcinid crabs have their life cycles in antagonistic scenarios, with their larvae developing in the sea and the juvenile/adult phases occurring on land. Adults migrate from land to sea to release their larvae, which return to land upon reaching the megalopa stage. Recruitment and early instar traits in gecarcinids crabs remain unknown, leading to some species lacking age-specific information. Despite massive recruitment observed in some insular gecarcinid species (e.g. Gecarcoidea natalis), recruits are generally expected to be few and exhibit cryptic behaviour, potentially occupying the burrows of conspecifics. We evaluated whether recruits of Johngarthia lagostoma on Trindade Island, Brazil, co-inhabit larger conspecific burrows, analysing this occurrence and examining their growth patterns, density, and body size across different lunar phases. Johngarthia lagostoma recruits inhabit conspecific burrows, either abandoned or occupied by adult crabs, but always with leaves stored in the inner chamber. Recruits in co-inhabiting behaviour reach a maximum carapace width of 7.3 mm, and after that, they are likely detected by the adults and possibly cannibalized or leave burrows naturally. During the full moon, the higher density and smaller size of recruits were recorded, indicating a recruitment lunar phase. It is crucial to ascertain the prevalence of co-inhabitation behaviours in other land crab species to expand the knowledge about recruitment patterns in these key community species.

Boric acid (BA) is an important mineral for plants, animals and humans that assists metabolic function and has both positive and negative effects on biological systems. The present study aimed to investigate the effects of different concentrations of BA added to the culture media, the quality and in vitro development potential of mouse embryos. Superovulated C57Bl6/6j female mice were sacrificed ∼18 hours after human chorionic gonadotropin (hCG) injection. Single-cell-stage embryos were collected from the oviduct, divided into experiment groups and cultured in embryo medium with supplemented BA+ in 5% CO2 at 37 °C until 96 hours at the blastocyst stage. The blastocyst development rates of 0, 1.62 × 10−1, 1.62 × 10−2, 1.62 × 10−3 and 1.62 × 10−4 µM BA were 51.52%, 73.47%, 77.36% and 81.13%, respectively. The in vitro development rates were significantly higher in the 1.62 × 10−3 (p < 0.05) and 1.62 × 10−4 µM BA groups than in the control group (p < 0.001). These results indicated that low BA doses influenced embryo development by positively affecting in vitro development rates, embryo cell numbers, biochemical parameters and development at the molecular level by pluripotent and antioxidant genes. Therefore, BA seems to play an important role on in vitro embryo development.

Several models of maternal undernutrition reveal impairment of testicular development and compromise spermatogenesis in male offspring. The expansion of the litter size model, valuable for studying the impact of undernutrition on early development, has not yet been used to evaluate the consequences of early undernutrition in the adult male reproductive system. For this purpose, pups were raised in either normal litter (ten pups/dam) or large litter (LL; sixteen pups/dam). On postnatal day 90, sexual behaviour was evaluated or blood, adipose and reproductive tissues were collected for biochemical, histological and morphological analysis. Adult LL animals were lighter and thinner than controls. They showed increased food intake, but decrease of retroperitoneal white adipose tissue weight, glycaemia after oral glucose overload and plasma concentration of cholesterol. Reproductive organ weights were not altered by undernutrition, but histopathological analysis revealed an increased number of abnormal seminiferous tubules and number of immature spermatids in the tubular lumen of LL animals. These animals also showed reduction in total spermatic reserve and daily sperm production in the testes. Undernutrition decreased the number of Sertoli cells, and testosterone production was increased in the LL group. Mitochondrial activity of spermatozoa remained unchanged between experimental groups, suggesting no significant impact on the energy-related processes associated with sperm function. All animals from both experimental groups were considered sexually competent, with no significant difference in the parameters of sexual behaviour. We conclude that neonatal undernutrition induces histological and physiological testicular changes, without altering sperm quality and sexual behaviour of animals.

Dietary restriction-influenced biological performance is found in many animal species. Pardosa pseudoannulata is a dominant spider species in agricultural fields and is important for controlling pests. In this study, three groups – a control group (CK group), a re-feeding group (RF group), and a dietary restriction group (RT group) – were used to explore development, mating, reproduction, and the expression levels of Vg (vitellogenin) and VgR (vitellogenin receptor) genes in the spider. The findings indicated that when subjected to dietary restriction, the carapace size, weight of the spiderlings, and weight of the adults exhibited a decrease. Furthermore, the preoviposition period and egg stage were observed to be prolonged, while the number of spiderlings decreased. It was also observed that re-feeding reduced cannibalism rates and extended the preoviposition period. Dietary restriction also affected the expression of the Vg-3 gene in the spider. These results will contribute to the understanding of the impact of dietary restriction in predators of pest control, as well as provide a theoretical foundation for the artificial rearing and utilisation of the dominant spider in the field.

The social-sexual environment is well known for its influence on the survival of organisms by modulating their reproductive output. However, whether it affects survival indirectly through a variety of cues without physical contact and its influence relative to direct interaction remain largely unknown. In this study, we investigated both the indirect and direct influences of the social-sexual environment on the survival and reproduction of the mite Tyrophagus curvipenis (Acari: Acaridae). The results demonstrated no apparent influence of conspecific cues on the survival of mites, but the survival and reproduction of mated female mites significantly changed, with the females mated with males having a significantly shortened lifespan and increased lifetime fecundity. For males, no significant difference was observed across treatments in their survival and lifespan. These findings indicate that direct interaction with the opposite sex has a much more profound influence on mites than indirect interaction and highlight the urgent need to expand research on how conspecific cues modulate the performance of organisms with more species to clarify their impacts across taxa.

Maternal intermittent fasting (MIF) can have significant effects on several tissue and organ systems of the body, but there is a lack of research on the effects on the reproductive system. So, the aim of our study was to analyze the effects of MIF on fertility. B6C3F1Crl (C57BL/6N × C3H/HeN) male and female mice were selected for the first part of the experiments and were analyzed for body weight and fat weight after administration of the MIF intervention, followed by analysis of sperm counts and activation and embryo numbers. Subsequently, two strains of mice, C57BL/6NCrl and BALB/cJRj, were selected and administered MIF to observe the presence or absence of vaginal plugs for the purposes of mating success, sperm and oocyte quality, pregnancy outcome, fertility status and in vitro fertilization (IVF). Our results showed a significant reduction in body weight and fat content in mice receiving MIF intervention in B6C3F1Crl mice. Comparing the reproduction of the two strains of mice. However, the number of litters was increased in all MIF interventions in C57BL/6NCrl, but not statistically significant. In BALB/cJRj, there was a significant increase in the number of pregnant females as well as litter size in the MIF treatment group, as well as vaginal plugs, and IVF. There was also an increase in sperm activation and embryo number and the MIF intervention significantly increased sperm count and activation. Our results suggest that MIF interventions may be beneficial for reproduction in mice.