Effects of Trifolium alexandrinum phytoestrogens on oestrous behaviour, ovarian activity and reproductive performance of ewes during the non-breeding season

Effects of Mixed Pasture Legume Phytoestrogens on Superovulatory Response and Embryo Quality in Angus Cows

Ovulation and artificial insemination rates have been observed to decrease in sheep and cows when exposed to dietary phytoestrogens at concentrations greater than 25 mg/kg DM. A grazing trial was undertaken to investigate the effects of coumestrol and other key phytoestrogens on the superovulatory response, embryo numbers and quality in beef cows grazing legume pastures. A 7-week controlled grazing trial was conducted with legume and ryegrass pasture treatments, with cows exposed to legumes at two timed treatments, 4 and 7 weeks. Twenty Angus cows were subjected to a conventional estrus synchronization and superovulation protocol. Embryos were recovered via conventional uterine body flushing 7 days post artificial insemination (AI). Numerous phytoestrogens were identified in both pasture and plasma samples, including coumestrol and formononetin. Concentrations of phytoestrogens in the pasture ranged from 0.001 to 47.5 mg/kg DM and 0 to 2.6 ng/mL in plasma. Approximately 50% of cows produced viable embryos 7 days post AI. A significant interaction between the effect of treatment groups on the embryo stage was observed (p < 0.05). The results suggest that concentrations of >25 mg/kg DM of phytoestrogens less than 20 days preceding AI may negatively affect oocyte developmental competence, reduce progesterone production and thus contribute to early embryonic loss.

Ovarian activity, hormone profile, pro-inflammatory cytokines and reproductive performance of buffalo cows fed diets with different estrogenicity

Buffalo cows play a vital role in milk and meat production; however, they are characterised by several reproductive disorders. Feeding diets with high oestrogenic activity may be a disrupting factor. This study aimed to evaluate the effects of feeding roughages with different oestrogenic activity on the reproductive performance of early postpartum buffalo cows. A total of 30 buffalo cows were equally stratified into two experimental groups and fed either Trifolium alexandrinum (Berseem clover, phytoestrogenic roughage) or corn silage (nonoestrogenic roughage) for 90 consecutive days. After 35 days from the beginning of the feeding treatments, buffalo cows in both groups were synchronized for oestrus using a double i.m. injection of 2 mL prostaglandin F2α , 11 days apart, subsequently, overt signs of oestrus were observed and recorded. Moreover, ovarian structures, numbers and sizes of follicles and corpora lutea, were ultrasonography examined at day-12 (represents Day 35 of feeding treatment), Day 0 (day of oestrus) and Day 11 after oestrous synchronization (mid-luteal phase). Pregnancy was diagnosed 35 days postinsemination. Blood serum samples were analysed for progesterone (P4 ), estradiol (E2 ), tumor necrosis factor (TNF-α), interlukein-1β (IL-1β) and nitric oxide (NO). The high performance liquid chromatography-analysis of roughages showed the abundance of isoflavones in Berseem clover, with about 58 times higher concentration than that in corn silage group. During the experimental period, the numbers of ovarian follicles of all size categories were higher in the Berseem clover group than that in the corn silage group. No significant difference in the numbers of corpora lutea was observed between both experimental groups, but lower (p < 0.05) diameter of corpus luteum was observed in the Berseem clover group than that in the corn silage group. The Berseem clover group had higher (p < 0.05) overall concentrations of blood serum E2 , IL-1β and TNF-α, but lower (p < 0.05) overall concentrations of blood serum P4 than those recorded in the corn silage group. Oestrous rate, onset of oestrus time and oestrous duration were not significantly affected by the treatment. The conception rate was significantly (p < 0.05) reduced in the Berseem clover group compared with that in the corn silage group. In conclusion, feeding roughage with a high oestrogenic activity such as Berseem clover can negatively affect the conception rate of buffalo cows. This reproductive loss seems to be associated with inadequate luteal function and P4 concentration during early pregnancy.

Environmental disruption of reproductive rhythms

Reproduction is a key biological function requiring a precise synchronization with annual and daily cues to cope with environmental fluctuations. Therefore, humans and animals have developed well-conserved photoneuroendocrine pathways to integrate and process daily and seasonal light signals within the hypothalamic-pituitary-gonadal axis. However, in the past century, industrialization and the modern 24/7 human lifestyle have imposed detrimental changes in natural habitats and rhythms of life. Indeed, exposure to an excessive amount of artificial light at inappropriate timing because of shift work and nocturnal urban lighting, as well as the ubiquitous environmental contamination by endocrine-disrupting chemicals, threaten the integrity of the daily and seasonal timing of biological functions. Here, we review recent epidemiological, field and experimental studies to discuss how light and chemical pollution of the environment can disrupt reproductive rhythms by interfering with the photoneuroendocrine timing system.

Isoflavones in Animals: Metabolism and Effects in Livestock and Occurrence in Feed

Soybeans are a common ingredient of animal feed. They contain isoflavones, which are known to act as phytoestrogens in animals. Isoflavones were described to have beneficial effects on farm animals. However, there are also reports of negative outcomes after the consumption of isoflavones. This review summarizes the current knowledge of metabolization of isoflavones (including the influence of the microbiome, phase I and phase II metabolism), as well as the distribution of isoflavones and their metabolites in tissues. Furthermore, published studies on effects of isoflavones in livestock species (pigs, poultry, ruminants, fish) are reviewed. Moreover, published studies on occurrence of isoflavones in feed materials and co-occurrence with zearalenone are presented and are supplemented with our own survey data.

Effects of phytogenic feed additives on the reproductive performance of animals

The reproductive performance of ruminants is economically significant, and its improvement is a primary goal of the livestock industry to ensure its sustainability. Several approaches have been developed to use phytogenics as feed additives for several proposes, such as reducing methane emissions, and as an alternative to antibiotics. Phytogenics have potent antioxidant, anti-inflammatory, immunomodulatory, and metabolism-regulatory properties, and they are present at high levels in animal feeds. This current review considers the potential use of medicinal herbs on the reproductive performance of animals. The influence of diet on the fertility complications commonly noted in ruminants is of global interest. Although the effects of phytogenics on ruminant digestion and absorption are well-explored, their impact on reproductive performance remains poorly investigated. This review focuses on the influence of phytogenics on semen quality, hormonal profiles, and hematobiochemical indices in male ruminants. Based on available data, phytogenics are perceived to improve oocyte quality, reproductive performance, and pregnancy. However, further more comprehensive research on the benefits and potential hazards of the use of phytogenics is required to improve reproductive performance in ruminants.

Characterization of Phytoestrogens in Medicago sativa L. and Grazing Beef Cattle

Phytoestrogens are plant-produced bioactive secondary metabolites known to play an integral role in plant defense that frequently accumulate in times of stress and/or microbial infection. Phytoestrogens typically belong to two distinct chemical classes; flavonoids (isoflavones) and non-flavonoids (lignans and coumestans). Upon consumption by livestock, high concentrations of phytoestrogens can cause long-term disruption in reproduction due to structural similarities with mammalian estrogens and their tendency to bind estrogen receptors. Wide variation in phytoestrogen concentration has been reported in pasture legumes and corresponding silage or hay. Lucerne is a common perennial pasture legume in temperate climates, but information on phytoestrogen production or accumulation in grazing livestock is currently limited. Therefore, metabolic profiling using UHPLC-MS-QToF was performed to identify and quantitate key phytoestrogens in both fresh and dried lucerne fodder from replicated field or controlled glasshouse environments. Phytoestrogens were also profiled in the blood plasma of Angus cattle grazing field-grown lucerne. Results revealed that phytoestrogens varied quantitatively and qualitatively among selected lucerne cultivars grown under glasshouse conditions. Fresh lucerne samples contained higher concentrations of coumestans and other phytoestrogenic isoflavones than did dried samples for all cultivars profiled, with several exceeding desirable threshold levels for grazing cattle. Coumestans and isoflavones profiled in plasma of Angus heifers grazing lucerne increased significantly over a 21-day sampling period following experimental initiation. Currently, threshold concentrations for phytoestrogens in plasma are unreported. However, total phytoestrogen concentration exceeded 300 mg·kg⁻¹ in fresh and 180 mg·kg⁻¹ in dried samples of selected cultivars, suggesting that certain genotypes may upregulate phytoestrogen production, while others may prove suitable sources of fodder for grazing livestock.

Improving Reproductive Performance and Health of Mammals Using Honeybee Products

Honeybee products have positive effects on the reproductive performance of mammals. Many honeybee product constituents are biologically active, with antioxidant, antimicrobial, antiviral, anti-inflammatory, immunomodulatory, antifungal, wound-healing, and cardio-protective properties. Honeybee products also improve male and female fertility rates by enhancing gamete cryopreservation, in vitro maturation and fertilization, and embryo development. Previously published studies confirmed their efficacy for alleviating reproductive toxicity caused by contaminants and lifestyle habits that impair overall health and well-being. However, high-dose oral administration of honeybee products may adversely affect the reproductive system, and unfavorable effects were alleviated by treatment cessation. For this reason, this review proposes that bioactive components from bee products can be used as a strategy for improving the reproductive performance and health of mammals.

Polyphenols in Farm Animals: Source of Reproductive Gain or Waste?

Reproduction is a complex process that is substantially affected by environmental cues, specifically feed/diet and its components. Farm animals as herbivorous animals are exposed to a large amount of polyphenols present in their natural feeding system, in alternative feed resources (shrubs, trees, and agro-industrial byproducts), and in polyphenol-enriched additives. Such exposure has increased because of the well-known antioxidant properties of polyphenols. However, to date, the argumentation around the impacts of polyphenols on reproductive events is debatable. Accordingly, the intensive inclusion of polyphenols in the diets of breeding animals and in media for assisted reproductive techniques needs further investigation, avoiding any source of reproductive waste and achieving maximum benefits. This review illustrates recent findings connecting dietary polyphenols consumption from different sources (conventional and unconventional feeds) with the reproductive performance of farm animals, underpinned by the findings of in vitro studies in this field. This update will help in formulating proper diets, optimizing the introduction of new plant species, and feed additives for improving reproductive function, avoiding possible reproductive wastes and maximizing possible benefits.

Soybean isoflavone affects in rabbits: Effects on metabolism, antioxidant capacity, hormonal balance and reproductive performance

Though soybean isoflavones (SBI) have pharmaceutical properties, the compounds also have endocrine disrupting activities that may adversely affect fertility of mammals. The effects of SBI on metabolism, antioxidant capacity, hormonal balance and reproductive performance of male rabbits were investigated. Adult male rabbits (n = 21) fed an isoflavone-free diet were orally treated with 0 (control; CON), 5 (small; LSBI) or 20 (large; HSBI) mg of SBI/kg body weight/day for 12 weeks. Both SBI doses resulted in lesser blood plasma total protein concentrations, while there were no effects on glucose and cholesterol concentrations compared to CON. The HSBI-treated males had the greatest (P <  0.05) blood plasma total antioxidant capacity and least malondialdehyde. Treatment with both SBI doses induced a 43% increase in triiodothyronine concentrations (P < 0.05) and 82% in reaction times (P <  0.001), while decreased sperm concentrations (P =  0.01) and blood plasma testosterone concentrations (P =  0.017) 26% and 19%, respectively. The total functional sperm fraction was less (P <  0.05) in the HSBI group; however, there was no effect of the LSBI treatment as compared to values for the CON group. The kindling rates of females mated to HSBI-treated males tended to be less (P =  0.081) than those of does mated with LSBI or CON males. In conclusion, only the HSBI treatment improved antioxidant status; whereas, treatment with both LSBI and HSBI doses induced a hormonal imbalance which led to an impaired testis function indicating the sensitivity of the adult male reproductive system to SBI actions.