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Fertile Eggs (fertile + egg)
Selected AbstractsPrimary sex ratios in birds: problems with molecular sex identification of undeveloped eggsMOLECULAR ECOLOGY, Issue 12 2003Kathryn E. Arnold Abstract Sex allocation studies seek to ascertain whether mothers manipulate offspring sex ratio prior to ovulation. To do so, DNA for molecular sexing should be collected as soon after conception as possible, but instead neonates are usually sampled. Here, we aim to identify and quantify some of the problems associated with using molecular techniques to identify the sex of newly laid avian eggs. From both fertilized and unfertilized chicken (Gallus gallus) eggs, we sampled (1) the blastoderm/disc, (2) vitelline membrane and (3) a mixture of (1) and (2). Thus, we replicated scenarios under which contaminated samples are taken and/or unfertilized eggs are not identified as such and are sampled. We found that two commonly used molecular sexing tests, based on the CHD-1 genes, differed in sensitivity, but this did not always predict their ability to sex egg samples. The vitelline membrane was a considerable source of maternal and probably paternal contamination. Fertile eggs were regularly assigned the wrong sex when vitelline membrane contaminated the blastoderm sample. The membrane of unfertilized eggs was always female, i.e. maternal DNA had been amplified. DNA was amplified from 47 to 63% of unfertilized blastodiscs, even though it was highly unlikely that DNA from a single haploid cell could be amplified reliably using these polymerase chain reaction (PCR) techniques. Surprisingly, the blastodiscs were identified as both males and females. We suggest that in these cases only maternal DNA was amplified, and that ,false' males, Z not ZZ, were detected. This was due to the reduced ability of both sets of primers to anneal to the W chromosome compared to the Z chromosome at low DNA concentrations. Overall, our data suggested that estimates of primary sex ratios based on newly laid eggs will be appreciably inaccurate. [source] Epoxiconazole causes changes in testicular histology and sperm production in the Japanese quail (Coturnix coturnix japonica)ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 11 2008Konstanze Grote Abstract The fungicide epoxiconazole (Epox), a triazole, belongs to the group of azole compounds that are extensively used as fungicides in various fruit crops. The frequent use of agricultural lands for wintering by migrating birds can be the source of their increased dietary intake of agricultural pesticides. We investigated whether exposure to Epox causes effects on avian fertility and reproduction, using the Japanese quail (Coturnix coturnix japonica) as a model species for the assessment of reproductive effects of pesticides in wild birds. Epox was administered to adult Japanese quail for three weeks at dietary levels of 10, 50, and 500 ppm, and possible effects on reproduction were investigated. Epox administration resulted in a significantly decreased number of spermatids in the 50- and 500-ppm dose groups. Histopathology showed a reduced number of testicular canaliculi with visible germ cells and a reduction in spermatid number. However, testis weight was not affected up to the highest dose level. No impact was observed on hormone levels, fertility, and reproductive outcome, as laying rate and percentage of fertile eggs were not altered. Likewise, treatment had no influence on the egg or chick parameters evaluated. A time- and dose-related transfer of Epox into the eggs was determined in all treatment groups. We conclude that dietary treatment of Japanese quail with 50 and 500 ppm of the triazole fungicide Epox resulted in a clear impact on the testis. The evaluation of the additional endpoints spermatid count and testicular histology have proven useful and are recommended for future studies on avian reproduction. [source] Isovitexin-2,- O -,-[6- O -E- p -coumaroylglucopyranoside] from UV-B irradiated Leaves of Rice, Oryza sativa L. Inhibits Fertility of Helicoverpa armigeraPHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 5 2007Merdelyn T. Caasi-Lit UV-B irradiated rice leaves (Oryza sativa L.) contained four closely related flavonoids, with either an isoorientin or isovitexin aglycone. These flavonoids have previously been purified and characterized, and were added to artificial diets of the African bollworm (Helicoverpa armigera Hübner) at 0.1× concentration found in irradiated rice leaves. Consumption of different diets had relatively small effects on laval, pupal and adult duration, weight and survival, indicating the insects lived near normal life cycles on all diets. However, one of the compounds, flavonoid IIa, isovitexin-2,- O -,-[6- O -E- p -coumaroylglucopyranoside], dramatically reduced the number of fertile eggs laid to 7% of control insects (P < 0.001) when added to insect diets at 18 nmol gFW,1 (14 ppm). A similar antifertility effect was observed when only the male partner consumed diet containing flavonoid IIa, indicating that the reduced fertility may be male specific. In contrast, the fecundity and fertility of insects eating diets containing the closely related flavonoids, isoorientin-2,- O -,-[6- O -E- p -coumaroylglucopyranoside] or isoorientin-2,- O -,-[6- O -E- p -feruloylglucopyranoside], were not significantly different to control diets. [source] Conservation breeding for reintroductions: assessing survival in a captive flock of houbara bustardsANIMAL CONSERVATION, Issue 3 2001Yolanda van Heezik Conservation breeding for reintroduction is becoming a popular option for restoring threatened populations. Whereas post-release results are widely reported in the conservation literature, little empirical information is presented on the captive populations that often make such releases possible, even though fecundity, fertility and survival rates can have an impact on the outcome and cost of wild population re-establishment. We present results of survival analyses carried out on a captive population of houbara bustards to determine peak periods of mortality, and by identifying sources of variations in mortality to recognize the potential impact of management practices on productivity. There were two main mortality peaks: during incubation (53% survival of fertile eggs), and by 6 months post-hatching (75% survival of hatchlings). Management-related variables influencing survival of eggs and chicks included the year when laid, the cohort of females laying them, and possibly sex. Most post-hatching deaths were due to trauma and infectious diseases. Trauma-related deaths usually follow collisions with cages, and imply selection for the captive environment, an undesirable trend in populations maintained for reintroductions. Reducing losses during incubation would have the largest impact on production of birds for reintroduction, enabling the release of more birds, and reducing the overall costs of the project. [source] Vibration Analysis on Incubating Eggs and Its Relation to Embryonic DevelopmentBIOTECHNOLOGY PROGRESS, Issue 3 2003Bart J. Kemps Coucke (1998) was the first to use acoustic resonance analysis to monitor embryo development in chicken eggs. He remarked that at around 100 hours of incubation, the course of the resonant frequency and damping changed abruptly in the case of fertile eggs. He also showed that these changes were related to a physiologic event during early embryonic development. The objective of our study is to monitor the course of the vibration parameters during the early incubation of chicken eggs and to relate these changes to egg and embryo characteristics. A total of 72 Hybro eggs were incubated vertically in a small incubator at standard conditions. Several egg parameters were measured before incubation. During the early stages of incubation the vibration behavior of these eggs was monitored. The time at which the damping of the vibration suddenly changed, the diameter of the eggs and their interaction were found to be significant explanatory variables in order to predict hatching time. A correlation coefficient r of 0.72 was obtained. [source] | ||||||||||