Endocrine profiles during doe-litter separation and the subsequent pregnancy in rabbits

This study was carried out to determine the effects of a transient doe-litter separation on plasma prolactin, LH, FSH, estradiol-17beta and progesterone concentrations before artificial insemination and during the subsequent pregnancy. Control does (n=12) had free access to nursing, whereas separated does (n=12) were kept away from their litters for 48 hours before artificial insemination. Both groups were inseminated on day 11 after parturition. Teat stimulation by suckling caused a high increase in prolactin concentrations in separated does (p < 0.0001). Basal prolactin concentrations were observed in both groups on days 8 and 18 of pregnancy. No effect of the treatment was detected on LH and FSH concentrations during the sampling period. A rise of estradiol-17beta concentrations was observed 48 hours after doe-litter separation, compared to control does and to previous values (p < 0.003). Both groups showed low progesterone concentrations before artificial insemination. Pregnant rabbits in both groups showed increased progesterone concentrations on days 8 and 18 of pregnancy. Lower estradiol-17beta concentrations were observed in control does on day 18 of pregnancy compared with separated rabbits (p < 0.003). The results suggest that a transient separation of nursing does from their litters before artificial insemination may promote high follicular steroidogenesis activity leading to increased estradiol-17beta concentrations. This hormonal change could be a result of several stimulatory actions probably triggered by the absence of suckling episodes and may affect the luteotrophic function during the subsequent pregnancy.     

Anatomy and uses of the mature leaves of three species of Sabal (Arecaceae) of the Yucatan, México

This paper describes the leaf anatomy of Sabal mauritiiformis (Karst.) Griseb. & H. Wendl., Sabal mexicana Mart. and Sabal yapa Wright ex Becc., three of the four most representative species of the Yucatán Península, in Mexico. These species are locally used: in the roofing of traditional homes, as food (fruits and apical buds), and in the production of hats, brooms and handicrafts. Leaf samples were collected in secondary growth of lower montane rainforest in the state of Quintana Roo and in two home gardens in the state of Yucatán. Herbarium samples were obtained, and samples of blade and petiole were fixed in formaline-acetic acid-alcohol. Cross incisions were made on the blade and petiole, and were dyed with safranin and toluidine blue O. The results show that S. mauritiiformis and S. yapa are morphologically alike: both are tall, slim palm trees; the leaf in S. mauritiiformis is a shorter palm-like structure compared with the other two species. The shape of the main nerve, as seen in cross section, is rectangular in the three species. The hastula in the three species is acuminate and adaxial. The foliar anatomic structure is similar in the three species, although there are some differences. The adaxial an abaxial epidermis of the blade consist of one layer and, superficially, the anticlinal walls are straight; the stomata are intercostal, of the tetracytic type, present on both surfaces in S. mexicana and S. yapa and only on the abaxial surface on S. mauritiiformis. The hypodermis is one layer thick in S. yapa and in S. mexicana and two layers thick in S. mauritiiformis. In the three species the palisade parenchyma consists of several undefined strata as the cells are similar-in shape and size--to the cells in the spongy parenchyma, so there is no marked difference between these strata and the spongy parenchyma seems almost continuous. Both fibrous and vascular bundles are distributed between the hypodermis and the palisade parenchyma; the fiber bundles can be found towards the abaxial surface while the vascular and fiber bundles are located towards the adaxial surface. The fibers, in the three species, are elongated, with the pointed tips, undivided and unseptated. One to three wide vessels of metaxilem can be seen in the vascular bundles, those in S. yapa being the widest in diameter. The vascular bundles are surrounded by thick fiber sheaths which come in pairs. The anatomic structure of the petiole is similar to that of the blade, and is characterized by the many vascular and fiber bundles dispersed in the parenchymatous tissue, and which are very resistant. The histological structure of the blade and petiole reflects strength and flexibility, qualities which make these plants adequate in the construction of roofs for rural housing and other buildings.     

Oestrus synchronisation of rabbit does at early post-partum by doe-litter separation or ECG injection: Reproductive parameters and endocrine profiles

Inseminating rabbit does at early post-partum, in combination with early weaning, can increase prolificacy (total kits born and still born per parturition) and decrease parturition intervals. Oestrus synchronisation increases fertility and prolificacy, while decreasing the number of inseminations required for gestation. However, little is known about the effectiveness of different oestrus synchronisation methods at early post-partum. In this study, does (n = 138) were artificially inseminated nine times (over a period of 1 year, kits weaned at 25 days), on day 4 post-partum after separation from the litter (for 48 or 24 h) or 48 h after 25 UI eCG injection. Plasma levels of prolactin and estradiol were also evaluated in a subsample of 12 multiparous lactating does per treatment, on days 2, 3 and 4 post-partum. The three treatments increased overall fertility of multiparous females compared to controls (which were not synchronised), but there were no differences among treatments in total kits born or stillborn. Does treated with eCG had a higher culling rate. The interval between parturitions and the number of inseminations required for gestation tended to decrease with increasing number of inseminations. In lactating does, there was an interaction between treatment and insemination order. Fertility decreased with increasing inseminations in eCG does but tended to increase above control values in the separated does until the fourth insemination. Control lactating does had significantly less kits per parturition compared to treatments, but eCG lactating does had more stillborn kits. Oestradiol levels increased on day 4 post-partum in all synchronised lactating does (and immediately before artificial insemination in 48 h doe-litter separation), so ovarian activity could be stimulated at early post-partum using all treatments. However, the increase could not be explained by prolactin levels, since there were no effects of suckling absence on plasma prolactin in separated does. In conclusion, separating does from the litter before insemination can be just as effective as eCG treatment, especially during for the first four inseminations.     

Prevalence of Sleep Apnea and Electrocardiographic Disturbances in Morbidly Obese Patients

Objective: To determine the prevalence of sleep apnea in morbidly obese patients and its relationship with cardiac arrhythmias. Research Methods and Procedures: Fifty‐two consecutive morbidly obese (body mass index ≥ 40 kg/m²) outpatients from the Obesity Clinic of the National Institute of Nutrition Salvador Zubirán underwent two nights of polysomnography with standard laboratory techniques. Electrocardiographic polysomnography signals (Lead II) were evaluated by two experienced cardiologists, and sleep complaints were measured with a standard sleep questionnaire (Sleep Disorders Questionnaire). In order to make comparisons between groups with different severities of sleep‐disordered breathing, we classified the patients in four groups using the apnea‐hypopnea index (AHI): Group 1, AHI 5 < 15 (n = 10); Group 2, AHI 15 < 30 (n = 10); Group 3, AHI 30 < 65 (n = 14); Group 4, AHI ≥ 65 (n = 17). Results: A wide range of sleep‐disordered breathing, ranging from AHI of 2.5 to 128.9 was found. Ninety‐eight percent of the sample (n = 51) had an AHI ≥ 5 (mean = 51 ± 37), and 33% had severe sleep apnea with AHI ≥ 65 with a mean nocturnal desaturation time of <65% over 135 minutes. Electrocardiographic abnormalities were present in 31% of the patients. Cardiac rhythm alterations showed an association with the level of sleep‐disordered breathing and oxygen desaturation. Discussion: We conclude that there is a high prevalence of sleep apnea in morbidly obese patients and that the risk for cardiac arrhythmias increases in this population in the presence of a severe sleep apnea (AHI ≥ 65) with severe oxygen desaturation (Sao ₂ ≤ 65%).     

Genetic variation of Batrachochytrium dendrobatidis is linked to skin bacterial diversity in the Pacific treefrog Hyliola regilla (hypochondriaca)

Symbiotic bacterial communities are crucial to combating infections and contribute to host health. The amphibian skin microbiome plays an important role in protecting their hosts against pathogens such as Batrachochytrium dendrobatidis (Bd), one of the causative agents of chytridiomycosis, which is responsible for dramatic amphibian population declines worldwide. Although symbiotic skin bacteria are known to inhibit Bd growth, an understanding of the relationship between Bd genetic variability, environmental conditions, and skin bacterial communities is limited. Therefore, we examined the associations between Bd infection load, Bd genetic diversity and skin bacterial communities in five populations of Hyliola regilla (hypochondriaca) from environmentally contrasting sites in Baja California, Mexico. We observed differences in Bd genetics and infection load among sites and environments. Genetic analysis of Bd isolates revealed patterns of spatial structure corresponding to the five sites sampled. Amphibian skin bacterial diversity and community structure differed among environments and sites. Bacterial community composition was correlated with Bd genetic differences and infection load, with specific bacterial taxa enriched on infected and un-infected frogs. Our results indicate that skin-associated bacteria and Bd strains likely interact on the host skin, with consequences for microbial community structure and Bd infection intensity.     

Influence of metabolic status on oocyte quality and follicular characteristics at different postpartum periods in primiparous rabbit does

Low reproductive performance of high-yield primiparous animals is closely associated with the metabolic stress caused by a simultaneous gestation and lactation. The aim of this work was (1) to analyze body composition and metabolic environment at three time points along lactation (at parturition time; in the lactation period [Day 11 postpartum]; and in the postweaning period [Day 32 postpartum]) of primiparous rabbit does (Oryctolagus cuniculus) and (2) to investigate the ovarian status at insemination time and the possible link with metabolic environment and with their reproductive performance. To this end, does were either submitted to a semi-intensive reproductive rhythm (Group S, inseminated on Day 11 postpartum) or an extensive rhythm (Group E, inseminated on Day 32 postpartum). Body energy (P < 0.05) and protein content (P < 0.001) as well as serum leptin (P < 0.05) and protein concentrations (P < 0.001) increased significantly along the postpartum period. At parturition, body lipid content was significantly lower and serum nonesterified fatty acids concentrations were significantly higher than that on Days 11 postpartum and 32 postpartum. Concerning ovarian status at insemination time, no significant differences were found in mean follicular stages, serum estradiol, progesterone, and prolactin (PRL) concentrations or in prolactin receptor (PRL-R) immunostaining. However, follicles in Group S showed a significantly higher apoptosis index than that of Group E (P < 0.001). The nuclear and cytoplasmic oocyte maturation rates of Group S were also significantly lower than that in Group E. In addition, conception rate and prolificacy were improved in Group E (P < 0.001 and P < 0.05, respectively). In conclusion, in the early postpartum period, metabolic status seems to impact negatively on ovarian follicle and oocyte quality leading to a poor reproductive outcome in primiparous rabbit does.     

Pituitary and ovarian response to transient doe-litter separation in nursing rabbits

The effects of a transient doe-litter separation on plasma prolactin, FSH and oestradiol concentrations, as well as the effect on LH response to exogenous GnRH administered at the time of artificial insemination, were determined in nursing rabbits. The effects on fertility, and litter size after parturition, as well as litter survival after doe-litter separation, were also studied. Control does (n = 12) had free access to nursing, whereas biostimulated does (n = 12) were separated from their litters for 48 h before artificial insemination. Plasma prolactin concentrations were decreased 24 h after the doe-litter separation (P < 0.05). The response of prolactin to suckling reached 10 times the basal values measured on day 10 after parturition (P < 0.0001). Increased oestradiol concentrations were found during the 48 h after the doe-litter separation: at 0 h, before artificial insemination (P< 0. 0001), 1.0-2.0 h after artificial insemination (P < 0.001), at 2.5 h (P < 0.05), 3.0 h (P < 0.01), and at 3.5 h (P < 0.05) after artificial insemination. Exogenous GnRH administered at the time of artificial insemination caused a greater LH response in does previously separated from their litters during 48 h (P < 0.01). The transient doe-litter separation did not affect plasma FSH concentrations, fertility, litter size or litter survival. These results suggest that a transient separation of nursing does from their litters before artificial insemination results in a decrease in plasma prolactin concentrations that could promote growth of follicular waves, and high steroidogenesis activity, leading to increased oestradiol concentrations and inducing higher sensitivity of the pituitary gland to exogenous GnRH. These findings associated to the absence of suckling episodes would lead to higher LH response and, therefore, exert a major effect on fertility.     

Endocrine profiles during doe-litter separation and the subsequent pregnancy in rabbits

This study was carried out to determine the effects of a transient doe-litter separation on plasma prolactin, LH, FSH, estradiol-17β and progesterone concentrations before artificial insemination and during the subsequent pregnancy. Control does (n=12) had free access to nursing, whereas separated does (n=12) were kept away from their litters for 48 hours before artificial insemination. Both groups were inseminated on day 11 after parturition. Teat stimulation by suckling caused a high increase in prolactin concentrations in separated does (p<0.0001). Basal prolactin concentrations were observed in both groups on days 8 and 18 of pregnancy. No effect of the treatment was detected on LH and FSH concentrations during the sampling period. A rise of estradiol-17β concentrations was observed 48 hours after doe-litter separation, compared to control does and to previous values (p<0.003). Both groups showed low progesterone concentrations before artificial insemination. Pregnant rabbits in both groups showed increased progesterone concentrations on days 8 and 18 of pregnancy. Lower estradiol-17β concentrations were observed in control does on day 18 of pregnancy compared with separated rabbits (p<0.003). The results suggest that a transient separation of nursing does from their litters before artificial insemination may promote high follicular steroidogenesis activity leading to increased estradiol-l7β concentrations. This hormonal change could be a result of several stimulatory actions probably triggered by the absence of suckling episodes and may affect the luteotrophic function during the subsequent pregnancy.     

The Lethal Fungus Batrachochytrium dendrobatidis Is Present in Lowland Tropical Forests of Far Eastern Panamá

The fungal disease chytridiomycosis, caused by Batrachochytrium dendrobatidis (Bd), is one of the main causes of amphibian population declines and extinctions all over the world. In the Neotropics, this fungal disease has caused catastrophic declines in the highlands as it has spread throughout Central America down to Panamá. In this study, we determined the prevalence and intensity of Bd infection in three species of frogs in one highland and four lowland tropical forests, including two lowland regions in eastern Panamá in which the pathogen had not been detected previously. Bd was present in all the sites sampled with a prevalence ranging from 15–34%, similar to other Neotropical lowland sites. The intensity of Bd infection on individual frogs was low, ranging from average values of 0.11–24 zoospore equivalents per site. Our work indicates that Bd is present in anuran communities in lowland Panamá, including the Darién province, and that the intensity of the infection may vary among species from different habitats and with different life histories. The population-level consequences of Bd infection in amphibian communities from the lowlands remain to be determined. Detailed studies of amphibian species from the lowlands will be essential to determine the reason why these species are persisting despite the presence of the pathogen.     

Screening of a synthetic peptide combinatorial library to identify inhibitors of the appressorium formation in Magnaporthe oryzae

The rice blast disease caused by Magnaporthe oryzae is one of the most devastating diseases of cultivated rice. One of the most important stages in the infective cycle of M. oryzae is the formation of the dome-shaped structure called appressorium. The purpose of the present study was to identify novel peptides to control the rice blast disease by blocking the appressorium formation through screening of a synthetic peptide combinatorial library. As result of the screening, a set of 29 putative bioactive peptides were identified, synthesized and assayed in comparison with the previously identified peptide PAF104. The peptides MgAPI24, MgAPI40 and MgAPI47 showed improved inhibitory activity on the M. oryzae appressorium formation. Our data show that these peptides have a differential effect on two developmental structures: appressoria and appressorium-like structures. Antimicrobial assays against M. oryzae and other non-target microorganisms showed a weak or no toxicity of these peptides, demonstrating their specific activity blocking the appressorium formation. Therefore, the outcome of this research would be useful in the development of novel target-oriented peptides to use in plant protection.