Reproductive disruption in adult female and male rats prenatally exposed to mesquite pod extract or daidzein.

Phytoestrogens are considered to be endocrine disruptors, since they can alter the endocrine system, thus disturbing many reproductive events. The intake of diets containing a high content of phytoestrogens has increased worldwide in human populations and in domestic animals. Phytoestrogens in maternal blood can pass through the placenta to the fetus in high amounts and can have long-term organizational effects. Mesquite (Prosopis sp) is a leguminous plant widely used to feed several livestock species, and is also used in the human diet. In this study we assessed the effects of exposure to mesquite pod extract during the periconception and pregnancy periods on the reproduction of male and female descendants. The females of three experimental groups received one of the following treatments: 1) vehicle injection; 2) mesquite pod extract or 3) the isoflavone daidzein during the periconception and pregnancy periods. Estrous cyclicity, sexual behavior and hormones, as well as uterine and vaginal epithelia were evaluated in the female descendants. In the males, sexual behavior and hormones, apoptosis in testicular cells and sperm quality were evaluated. In females the following was observed: alterations in estrous cycles, decreased sexual behavior, estradiol and progesterone levels, increased uterine and vaginal epithelia. In males, we observed a decrease in sexual behavior, testosterone and sperm quality, and apoptosis increased in testicular cells. All these effects were similar to those caused by daidzein. These results indicate that prenatal exposure to mesquite pod extract or daidzein, administered to females before and during pregnancy, can disrupt normal organizational-activational programming of reproductive physiology in female and male descendants.

The effects of female-male friendships on male postcopulatory levels of oxytocin and vasopressin, and sperm parameters in Macacaarctoides.

Male and female stump-tailed macaques (Macaca arctoides) form close relationships akin to human friendships. Oxytocin and vasopressin modulate these and other social relationships and reproductive behavior and physiology in various mammal species. Besides the behavioral effects of oxytocin, this hormone plays an essential role in the ejaculatory process, favoring sperm transport upward the female reproductive tract. Therefore, we investigated the influence of friendships on postcopulatory serum levels of oxytocin and vasopressin in the stump-tailed macaque (Macaca arctoides). In addition, we searched for a correlation between this kind of social relationship and sperm transport in the vagina during the periovulatory and luteal phases. Six female and six male adult macaques having different friendship indices served as experimental animals. Allocated in 57 mating pairs combinations, these animals were allowed to copulate once in the luteal and periovulatory phases. Blood samples were collected from each animal finishing copulation to measure oxytocin and vasopressin. Afterward, we profoundly sedated the females and collected three semen samples from the vagina every 10 min to perform spermatobioscopies. Males' post-copulation oxytocin values increased along with the friendship index, while vasopressin behaves oppositely. Sperm concentration and immotile and motile sperm decreased from one sample to another as male-female closeness increased. Finally, in the periovulatory phase, only in the first vaginal sample, sperm velocities significantly increased with friendship indices. Our results showed that in stump-tailed macaques, heterosexual friendships promote higher postcopulatory oxytocin concentrations and better physiological conditions to males, which probably enhance reproductive success.

Neuroendocrine disruption is associated to infertility in chronically stressed female rats.

Infertility is a growing worldwide public health problem, and stress is a main factor exerting detrimental effects on female reproduction. However, knowledge regarding the neuroendocrine changes caused by chronic stress in females is limited. Therefore, this study assessed the effects of stress on hormones that control female reproduction during the proestrus and diestrus stages of the estrous cycle, as well as its effects on fertility. Adult females were assigned to either a control or a stress group. Stress consisted of exposure, for 15 min, to cold-water immersion daily for 30 days. Estrous cyclicity, female sexual behavior, as well as hypothalamic kisspeptin, gonadotropin releasing hormone (GnRH) content, serum luteinizing hormone (LH), estradiol (E2), progesterone (P4), corticosterone (CORT) and fertility were assessed after chronic stress. The results show that chronically stressed females exhibited disrupted estrous cyclicity, decreased receptivity, low pregnancy rates and lower numbers of fetuses. The content of Kisspeptin and GnRH in the Anteroventral Periventricular/medial Preoptic Area decreased during proestrus, while Kisspeptin increased in the Arcuate nucleus in proestrus and diestrus. Serum LH decreased only during proestrus, whereas E2 and P4 concentrations decreased during proestrus and diestrus, with a concomitant increase in CORT levels in both stages. As a whole, these results indicate that chronic stress decreases Kisspeptin content in AVPV nucleus and GnRH in POA in females, and might induce disruption of the LH surge, consequently disrupting estrous cyclicity and fertility, leading to lower rates of pregnancy and number of fetuses.

Prenatal stress decreases sperm quality, mature follicles and fertility in rats.

Prenatal stress disrupts reproductive function in females and males. These alterations have primarily been related to maternal corticosteroid fetal programming due to the stress response, affecting the fetus and causing long-lasting effects. The aim of this study was to investigate the influence of prenatal stress on male and female fertility. Dams were exposed to stress by immersion in cold water twice a day for the last week of gestation (days 15-21). In the adulthood, sperm quality, mature follicles, sexual hormones and fertility were assessed in female and male progeny. The results in prenatally stressed females showed lower body weight, longer estrous cycles, lower estradiol and progesterone, and lower number of pups. In prenatally stressed males, lower body weight, increased testicular cell death, as well as decreased testosterone levels, sperm quality, and fertility were observed. Aside from these effects, corticosterone levels in prenatally stressed males and females increased. These results show that prenatal stress can markedly influence infertility in adult female and male progeny. Abbreviations: 3ß-HSD: 3ß hydroxysteroid dehydrogenase; CRH: corticotropin releasing hormone; DEX: dexamethasone; ERα: estrogen receptor alpha; H-E: hematoxylin-eosine; HPA: hypothalamus-pituitary-adrenal; KISS: Kisspeptin; ORW: ovarian relative weight; PBS: phosphates; PS: prenatally stressed; PRW: prostatic relative weight; ROS: reactive oxygen species; SRW: seminal relative weight; TdT: terminal deoxynucleotidyl transferase; TUNEL: terminal deoxynucleotidyl transferase dUTP Nick-end labelling; TRW: testicular relative weight; URW: uterine relative weight.

Effects of crowding and water restriction stress on creole goat reproduction in the Oaxacan Sierra Mixteca, Mexico.

Chronic stress disrupts reproductive efficiency. Yet, the manner in which stress disturbs reproduction in goats is currently unknown. The Oaxacan Mixteca region is one of Mexico's poorest, with high levels of deforestation, high ambient temperatures, and lack of water. Native goats of the Oaxacan Mixteca Region live in these stressful conditions, as well as in overcrowded and water restricted conditions. Therefore, the aim of this study was to evaluate the effects of these very stressful conditions on the reproduction of male and female goats. Control group was uncrowded, with daily water supply; stress group was overcrowded, with water restriction. The study was conducted from September 2015 to February 2016; the expression of reproductive behaviour and variations of cortisol levels were assessed. In females, oestradiol and progesterone were evaluated during the oestrous cycle. In males, testosterone levels were evaluated before and during reproductive activity. Sexual behaviour decreased in stressed goats: approaching, tail swishing, urination, vaginal discharge and flank contraction decreased in stressed females. Anogenital sniffing, licking, Flehmen reflex, bleating, mount attempts and mounts decreased in male goats. Cortisol levels in stressed animals were higher compared with control animals. Oestradiol and Progesterone levels in stressed females were significantly lower during the follicular and luteal phase, respectively, compared with control females. Testosterone levels in stressed males were lower than in control males, both before and during reproduction. These results indicate that even though goats from the Oaxacan Mixteca Region are habituated to their environmental conditions, they are still stressed by them, as shown by a higher activation of the adrenal axis in stressed goats than in control goats. High cortisol levels may induce low oestradiol levels in females and low testosterone levels in males, as well as a disruption in the expression of their reproductive behaviour.

Progesterone and estradiol profiles in different reproductive stages of captive collared peccary (Pecari tajacu) females assessed by fecal metabolites.

The study determined the fecal progesterone and estradiol profiles in different reproductive stages of captive collared peccary (Pecari tajacu) females from eastern Mexico. Fifteen adult females were included. At the start of the study the females were either pregnant (early, mid, or late pregnancy), lactating, or non-lactating of unknown pregnancy status. Feces from each female were collected once a week during nine consecutive months to determine concentrations of fecal progesterone and estradiol metabolites using ELISA. Progesterone was similar in early (2048±285ng/g), mid (2254±274ng/g), and late pregnancy (2491±374ng/g), and in early-pregnant and non-lactating females (1154±274ng/g). Progesterone in lactating females (442±255ng/g) was lower than in females at any stage of pregnancy, but was similar to non-lactating females. Overall progesterone in pregnant females (2229±173ng/g) was higher than in lactating and non-lactating females together (772±189ng/g). Estradiol was similar in early (66±8ng/g), mid (83±9ng/g), late pregnant (109±15ng/g), and non-lactating females (64±9ng/g). Estradiol in lactating females (34±8ng/g) was similar to estradiol in early-pregnant and non-lactating females, but was lower than in females in late and mid pregnancy. Overall estradiol in pregnant females (79±6ng/g) was similar to non-lactating females, but higher than in lactating females. The progesterone and estradiol profiles of captive collared peccary females at different reproductive stages were determined by assessing concentrations of fecal hormone metabolites.

EARLY ONSET OF THE REPRODUCTIVE SEASON IN CAPTIVE WHITE-TAILED DEER ( ODOCOILEUS VIRGINIANUS VERAECRUCIS) IN EASTERN MEXICO.

The white-tailed deer ( Odocoileus virginianus) inhabits a wide latitudinal range in the Americas. Deer species dwelling throughout wide latitudinal ranges have developed subspecies with variations in their reproductive seasonality. In northern subspecies of white-tailed deer, such as those from Canada and the United States, the breeding season occurs from October through December. Odocoileus virginianus veraecrucis is a subspecies that inhabits eastern Mexico, and because its reproductive season has not been studied, it is believed to be similar to that from northern subspecies. The objective of the study was to determine the onset of the breeding season and the profile of fecal steroid hormone metabolites throughout the year in captive white-tailed deer subspecies veraecrucis in Mexico. Two groups of adult deer were included: 1) six does and one buck at a Wildlife Conservation Unit, and 2) five does and one buck at a zoo. From each group of deer, representative fecal samples were collected on a weekly basis for 1 yr for fecal analysis of progesterone and estradiol in the does, and testosterone in the bucks. Data on antler casting, parturitions, and velvet shedding were recorded. Progesterone was high during pregnancy and low throughout the parturition period. Estradiol fluctuated throughout the year. Testosterone was high during the rut and low after antler casting. Antlers were cast in March and velvet was shed in August at both sites. Parturitions started in February at the zoo and in April at the Wildlife Unit. In captive white-tailed deer subspecies veraecrucis the breeding season started in July, and therefore earlier than what has been reported for subspecies from northern latitudes.

Faecal cortisol concentrations as indicator of stress during intensive fattening of beef cattle in a humid tropical environment.

The study evaluated the concentrations of faecal cortisol metabolites (FCM) in intensively fattened beef cattle from a feedlot in a humid tropical environment. A total of 360 bulls weighing 271-371 kg were kept confined in pens from the start to the end of the fattening period (FP). At 24 h after arriving at the feedlot, cattle were distributed into the pens according to their live weight: 271-320 kg, 321-370 kg, and >370 kg. At the start of the FP, four pens of each weight group were randomly selected, and in each of them 10 faecal samples were obtained from 10 randomly selected bulls; this sampling was repeated in the same pens and in each weight group at the middle and end of the FP. The FCM were measured through enzyme immunoassay. The 271-320 kg group had higher FCM at the end of the FP (P < 0.05), the 321-370 kg group had similar FCM throughout the FP (P > 0.05), and the >370 kg group showed higher FCM at the start and end of the FP (P < 0.05). Higher FCM were observed at the middle of the FP in the 321-370 kg group, and at the end of the FP in the 271-320 kg and >370 kg groups (P < 0.05). Mean FCM obtained throughout the FP were within normal ranges for cattle, suggesting that appropriate management in feedlots in humid-tropical regions can provide bulls with a low-stress environment.

Efecto del líquido folicular equino libre de esteroides sobre la secreación de FSH en ovejas en anestro estacional y la presentación del esto inducido con PGF2a en ovejas ciclando / Effect of steroid free equine follicular fluid on FSH secretion in seasonally anestrous ewes and on the onset of estrous induced with PGF2a in cyclic ewes

Con el propósito de conocer si la administración del líquido folicular equino libre de esteroides (LFE) suprime la secreción de FSH en ovejas en anestro estacional y retrasa la presentación del estro inducido con prostaglandina F2a, se realizaron dos experimentos. En el primer experimento se utilizaron 19 ovejas en anestro estacional divididas en dos grupos. El grupo tratado (n=10) recibió por vía intravenosa 3 ml de LFE cada 8 h durante 5 días. El grupo testigo (n=9) recibió solución salina fisiológica (SSF) en lugar de LFE. El LFE fue tratado previamente con carbón-dextrán para remover la fracción de hormonas esteroides. En ambos grupos se obtuvieron muestras de sangre cada 4 h durante el periodo de aplicación del LFE para determinar FSH mediante radioinmunoanálisis en fase líquida. Se compararon las concentraciones de FSH mediante un análisis de varianza, utilizando, utilizando como variables independientes el tratamiento y la hora en que tomó la muestra. Las concentraciones de FSH fueron significativamente menores (P<0.05) en las ovejas tratadas con LFE. En el segundo experimento se utilizaron 22 ovejas adultas ciclando. A todas las ovejas se les insertó una esponja intravaginal impreganda con 45 mg de acetato de luorogestona* para la sincronización del estro. El día 11 del ciclo subsecuente al estro sincronizado (día 0 = día del estro), todas las ovejas fueron tratadas con 15 mg de PGF2a,** para provocar la regresión del cuerpo lúteo. Las ovejas así tratadas se dividieron en 2 grupos. El grupo tratado (n=11) recibió por vía intravenosa 3 ml de LFE cada 8 horas por 72 horas a partir de la aplicaicón de la PGF2a. El grupo testigo (n=11) se recibió SSF en lugar de LFE. Se detectaron estros 3 veces al día utilizando un macho con mandil, y se consideró el inicio del estro cuando la hembra aceptó la monta por primera vez. El intervalo de la administración de PGF2a a la presentación del estro fue significativamente mayor en las ovejas que recibieron LFE (131ñ9.9 h) que en las del grupo testigo (44ñ3.9 h). Se concluye que el tratamiento con LFE suprime las concentraciones de FSH en ovejas en anestro estacional y retrasa la presentación del estro sincronizado por PGF2a en ovejas cíclicas, lo que indica que el LFE es una fuente rica en inhibina, que tiene actividad biológica en ovejas

Determinación de la hormona luteinizante con un radioinmunoanálisis (RIA) homólogo en cabras estimuladas con diferentes dosis de hormona liberadora de las gonadotropinas (GnRH) / Determination o luteinizing hormone with homologous raioimmunoassay (RIA) in goats stimulated with various doses of gonadotrophin liberating hormone (GnRH)

El presente estudio informa la validación clínica del RIA homológo de LH en cabras mestizas con estro inducido y estimuladas con dosis únicas de GNRH. Se trabajó con 24 cabras distribuidas al azar en cinco grupos. A los grupos del I al IV (n5) se les colocó esponjas con acetaro de fluorogestona (FGA) a dosis de 45 mg/animal, durante nueve días, no así al V (n4), pues se le mantuvo como testigo. Después de 24 horas de retiradas las esponjas los grupos I, II y III, se estimularon por vía intravenosa con 2, 4 y 8 µg de GnRH respectivamente, a los grupos IV y V se les administró solución salina. El muestreo se realizó cada 15 minutos, durante un periodo de cinco horas (2 h antes del estímulo con GnRH o solución salina y 3 h después). Los niveles circulantes de LH se determinaron con un sistema de RIA homólogo en fase líquida con segundo anticuerpo como sistema de separación. El grupo I presentó un pico de LH de 21.4 ñ 7.4 ng/mL; el grupo II de 13.4 ñ 3.16 ng/mL, ambos con una P<0.05 con respecto al grupo V, el cual mostró un valor promedio de LH de 4.72 ñ 0.28 ng/mL; el grupo III presentó un pico de 11.4 ñ 8.60 ng/mL sin que resultara significativo; en el grupo IV no se detectaron niveles de LH. Ni un solo animal mostró niveles de progesterona durante 21 días posteriores al estímulo con GnRH, con base en lo anterior se sugiere que los picos de LH detectados durante el experimento no fueron preovularotios