Stimulating effects of quercetin on sperm quality and reproductive organs in adult male rats

Aim： To investigate effects of quercetin on weight and histology of testis and accessory sex organs and on sperm quality in adult male rats. Methods： Male Sprague-Dawley rats were injected s.c. with quercetin at the dose of 0, 30, 90, or 270 mg/kg body weight/day （hereafter abbreviated Q0, Q30, Q90 and Q270, respectively）, and each dose was administered for treatment durations of 3, 7 and 14 days. Results： From our study, it was found that the effects of quercetin on reproductive organs and sperm quality depended on the dose and duration of treatment. After Q270 treatment for 14 days, the weights of testes, epididymis and vas deferens were significantly increased, whereas the weights of seminal vesicle and prostate gland were significantly decreased, compared with those of Q0. The histological alteration of those organs was observed after Q270 treatment for 7 days as well as 14 days. The sperm motility, viability and concentration were significantly increased after Q90 and Q270 injections after both of 7 and 14 days. Changes in sperm quality were earlier and greater than those in sex organ histology and weight, respectively. Conclusion： Overall results indicate that quercetin might indirectly affect sperm quality through the stimulation of the sex organs, both at the cellular and organ levels, depending on the dose and the duration of treatment. Therefore, the use of quercetin as an alternative drug for treatment of male infertility should be considered. （Asian J Androl 2008 Mar. 10： 249-258）

Hematology of Wild Caught Hoplobatrachus rugulosus in Northern Thailand

The rice field frog Hoplobatrachus rugulosus is an important anuran species found in wetlands throughout Thailand. At present, the hematological parameters of wild populations are unknown. Therefore, hematological and morphological characteristics of peripheral blood cells of wild-caught H. rugulosus were examined. Thirty-three adult frogs （17 male and 16 female frogs） were collected from a natural population in Nan Province, northem Thailand during the wet season of 2014. Blood samples were analyzed by packed cell volume （PCV） and blood cell counts from hemocytometer and Giemsa-stained blood smears. The mean PCV of male frogs （30.70% ±6.07%） was significantly higher than that of the female frogs （25.09%± 4.85%）. The mean number of lymphocytes and neutrophils also showed significant sex-related differences. Moreover, the morphometric analysis of blood cells revealed dimensions as follows： erythrocytes （17.96 ±1.44 μm length × 11.50 ± 1.09μm width）, immature erythrocytes （14.91 ± 2.20 μm diameter）, thrombocytes （13.93± 3.14 μm length × 7.05 ± 1.31 μm width）, lymphocytes （11.01 ±2.69μm diameter）, monocytes （12.04±2.40 μm diameter）, neutrophils （12.58 -±2.08μm diameter）, basophils （13.60 ± 2.17μm diameter） and eosinophils （12.33 ± 2.95 μm diameter）. Overall, the hematological parameters obtained in this study could be regarded as the first report and a crucial baseline data of wild H. rugulosus in Thailand that can be used for monitoring the health status of this anuran.

Effect of Incubation Temperature on the Somatic Development of the Snail-Eating Turtle Malayemys macrocephala

The rising average global temperature can lead to changes both in the physical and biological environments and affect the survival of organisms. Freshwater turtles are considered to be susceptible species since their development is dependent on incubation temperature. In Thailand, although several species of freshwater turtle are present, the extent of their susceptibility to temperature change is unknown due to the lack of information on their developmental patterns. This research, therefore, is aimed at examining the effects of temperature on somatic development in Malayemys macrocephala, a native species and the most common freshwater turtle in Thailand. Turtle eggs were collected from rice fields in the central part of Thailand during December 2011 to February 2012 inclusive. Eggs （237-238 per condition） were incubated in microprocessor-controlled incubators at three different temperatures （26 ℃, 29℃ and 32℃） with a relative humidity in excess of 80%. Each week, until the remaining eggs hatched, eggs were randomly selected, removed and dissected to reveal the developing embryo to screen for developmental stage and any abnormalities. The incubation period （lay to hatch） was not significantly different among the three temperatures （115 ±11.3 d, 115 ±20.3 d and 109±17.8 d, respectively）, but the growth patterns, as indicated by the stages of development and carapace lengths, were significantly different. At a high temperature （32℃）, turtle embryos showed a significantly faster growth rate than at the intermediate and low temperatures （29 ℃and 26 ℃）, but had a significantly （over 3.3-fold） higher incidence of developmental abnormalities （especially deformed bodies） than at the lower temperatures. Overall, the results indicate that incubation temperature is an important variable affecting the somatic development of this tropical freshwater turtle species, whilst abnormalities in the embryonic body may be a sensitive indicator of extreme thermal stress.

Morphometric and Gravimetric Parameters of the Rice Frog <i>Fejervarya limnocharis</i>Living in Areas with Different Agricultural Activity

Use of agrochemicals in agricultural activity can lead to environmental contamination and affect non-target organisms including amphibians. In northern part of Thailand, there are many areas where agrochemicals, specifically herbicides, have been used for a long time. In this study, the rice frog Fejervarya limnocharis was used as a sentinel species to monitor potential relationship between agricultural activity, in form of herbicide utilization, and altered morphometric and gravimetric parameters. Frogs were field-collected on monthly basis during July 2010-June 2011 from a paddy field with intensive herbicide usage and a reference organic paddy field with no history of herbicide usage. Frogs were subjected to morphometry and gravimetry of liver, kidney, gonad and body. The results showed that condition factor of frogs in the contaminated site were significantly lower than those in the reference site, indicating potential impact on overall health. The gravimetric results showed that liver weight of frogs from the contaminated site were significantly higher than those in the reference site, indicating potential exposure to xenobiotics. There was no significant difference in kidney and testicular weight between these two sites. However, the frog from the impacted site had significantly higher ovarian weight than those from the reference site, indicating potential exposure to estrogenic substance. Overall, the results of this study could be used as early warnings of environmental health problems for other vertebrates living near the agricultural areas including human.

Green Turtle, <i>Chelonia mydas</i>, Nesting and Temperature Profile of the Nesting Beach at Huyong Island, the Similan Islands in Andaman Sea

Global change in temperature is regarded as a serious natural disaster that may cause extinction of organisms. Green turtle, Chelonia mydas, is not only an endangered species but also a species with temperature dependent sex determination that could be affected by the global warming. In this study, nesting and temperature profile of C. mydas nesting beach at HuyongIsland, the most important nesting site of C. mydas in Andaman Sea of Thailand, were studied in order to monitor a potential effect of regional climate change on the green turtle nesting activity and habitat. Nesting activities were surveyed during May-August 2011 and temperature profiles of the nesting beach were monitored for 58 days during the normal incubation period of this species. The total of 25 nests with clutch size of 105 ± 25 eggs was found during this study period suggesting normal nesting activity of the green turtle. Temperature profile of the nesting beach showed similar trend among nests with no clear influence of the vegetation cover. Mean nest temperature at the middle-third period, corresponding to the temperature-sensitive period of C. mydas, ranged from 28.3°C to 28.9°C, suggesting a slightly male-biased sex ratio of the offspring. Overall, temperature profile of the nesting beach showed little or no indication of adverse effects of regional increase in temperature on nesting activity and egg incubation of the green turtle at this period.

Reproductive Mode of Fejervarya limnocharis (Anura:Ranidae) Caught from Mae Sot,Thailand Based on Its Gonadosomatic Indices

Amphibians show a variety of reproductive modes and strategies. The cyclicity and continuity of reproduction can often be predicted from the annual gonadosomatic index trends in a species specific manner. This research aims to document the female and male gonadosomatic index profiles and to ascertain the reproductive cyclicity or continuity of Fejervarya lirnnocharis （Anura： Ranidae） caught in Mac Sot, Tak Province, Thailand. Frogs were collected monthly between November 2007 and October 2009 in rice fields and their surrounding areas in the study site. For each frog, total weight and ovarian/testicular weight were measured to obtain the female and male gonadosomatic index. The number of female individuals with mature eggs （postvitellogenic eggs） was also counted. The results showed that female frogs had two main surges of increased GSI in March and September of 2008. Alternatively, male frogs showed a more gradual increase and decrease in gonadosomatic index, thus the index remaining high throughout the year. This study concluded that while F. limnocharis in this area is essentially a continuous breeder, it is more optimized for a cyclic reproduction mode with two breeding cycles during the rainy season.

Check Dams in an Ephemeral Stream in a Tropical Deciduous Forest Extend Water Period with Minimal Effect on Reptile Assemblage

Although numerous check dams have been constructed in many countries, and its effect on physical factors were well documented, only a few reports were available on its effect on biotic component in adjacent area. This research aims to address effects of the check dam on reptile assemblage in an ephemeral stream based on an assumption that reptile live in the stream and adjacent area may be susceptible to prolonged hydroperiod after check dam construction. Ten stream transects and 40 terrestrial strip transects, including 5, 10, 25, and 50 m from the stream, were used to monitor reptile diversity and composition in a deciduous forest of northern Thailand during April 2009 to February 2011. Physical factors related to water pattern in the stream and the terrestrial habitats were also collected. Results on physical factors indicated that the water pattern and soil moisture in the stream, as well as leaf litter moisture in the terrestrial habitat were increased as a result of the check dam. However, rarefaction curve indicated that reptile diversity was not significantly different between pre- and post-check dam periods in every transect. Moreover, Morisita’s index of similarity indicated that reptile composition between pre- and post-check dam periods was approximately the same (86% - 100%). These results indicated that reptile assemblage was not affected by the check dam. It can be concluded based on data of one year after the check dam construction that check dam can effectively prolong water and moisture to the habitat with minimal effect on reptile assemblage in the area.

Thermosensitive period for sex determination of the tropical freshwater turtle Malayemys macrocephala

Many egg-laying reptiles possess temperature-dependent sex determination(TSD)in which outcome of gonadogenesis is determined by incubation temperature during a temperature-sensitive period of development.Prior studies on Malayemys macrocephala showed that incubation temperatures influence gonadal development and suggested that M.macrocephala exhibits TSD.However,information on the temperature-sensitivity period in this species was unknown until the current study.Turtle eggs were collected from rice fields in central Thailand from December 2016 to February 2017.In the laboratory,eggs were incubated at male-biased temperature(26°C)and shifted to female-biased temperature(32°C),or vice versa.Single shift experiments were performed systematically during embryonic stages 13–21.After hatching,sex of individual turtles was determined by histological analysis.We found that the sex determination of M.macrocephala is affected by temperature up to stage 16 of embryonic development.