Maternal provisioning interacts with incubation temperature to affect hatchling mercury exposure in an oviparous reptile.

The thermal environment experienced by developing embryos can influence the utilization of maternally provisioned resources. Despite being particularly consequential for oviparous ectotherms, these dynamics are largely unexplored within ecotoxicological frameworks. Here, we test if incubation temperature interacts with maternally transferred mercury to affect subsequent body burdens and tissue distributions of mercury in hatchling American alligators (Alligator mississippiensis). Nine clutches of alligator eggs were collected from a mercury-contaminated reservoir and incubated at either female- or male-promoting temperatures. Total mercury (THg) concentration was measured in egg yolk collected during incubation and in a suite of tissues collected from hatchlings. THg concentrations in residual yolk and blood were higher in hatchlings incubated at cooler, female-promoting temperatures compared to the warmer, male-promoting temperatures. THg concentrations in most tissues were positively correlated with THg concentrations in blood and dermis, and egg yolk THg concentration was the best predictor of THg concentration in many resultant tissues. Our results highlight a hereto unknown role of the developmental environment in mediating tissue specific uptake of contaminants in an oviparous reptile.

A comparison of uterine contractile responsiveness to arginine vasopressin in oviparous and viviparous lizards.

Nonapeptides and their receptors regulate a diverse range of physiological processes. We assessed the contractile responsiveness of uteri from the squamate viviparous-oviparous species pair, Pseudemoia entrecasteauxii and Lampropholis guichenoti, as well as the bimodally reproductive species, Saiphos equalis, to arginine vasopressin (AVP). We assessed the resulting uterine contractility as a function of pregnancy status, species and parity mode. We also measured mRNA abundance for the nonapeptide receptor, oxytocin receptor (oxtr), in uteri from P. entrecasteauxii and L. guichenoti and compared expression across pregnancy status and parity mode. We found that pregnant uteri exhibited a significantly greater contractile response to AVP than non-pregnant uteri in all three lizard species studied. Cross-species comparisons revealed that uteri from viviparous P. entrecasteauxii were significantly more responsive to AVP than uteri from oviparous L. guichenoti during both pregnant and non-pregnant states. Conversely, for non-pregnant S. equalis, uteri from viviparous individuals were significantly less responsive to AVP than uteri from oviparous individuals, while during pregnancy, there was no difference in AVP contractile responsiveness. There was no difference in expression of oxtr between L. guichenoti and P. entrecasteauxii, or between pregnant and non-pregnant individuals within each species. We found no significant correlation between oxtr expression and AVP contractile responsiveness. These findings indicate that there are differences in nonapeptide signalling across parity mode and suggest that in these lizards, labour may be triggered either by an increase in plasma nonapeptide concentration, or by an increase in expression of a different nonapeptide receptor from the vasopressin-like receptor family.

Transgenerational effects from single larval exposure to azadirachtin on life history and behavior traits of Drosophila melanogaster.

Azadirachtin is one of the successful botanical pesticides in agricultural use with a broad-spectrum insecticide activity, but its possible transgenerational effects have not been under much scrutiny. The effects of sublethal doses of azadirachtin on life-table traits and oviposition behaviour of a model organism in toxicological studies, D. melanogaster, were evaluated. The fecundity and oviposition preference of flies surviving to single azadirachtin-treated larvae of parental generation was adversely affected and resulted in the reduction of the number of eggs laid and increased aversion to this compound over two successive generations. In parental generation, early exposure to azadirachtin affects adult's development by reducing the number of organisms, delay larval and pupal development; male biased sex ratio and induced morphological alterations. Moreover, adult's survival of the two generations was significantly decreased as compared to the control. Therefore, Single preimaginal azadirachtin treatment can affect flies population dynamics via transgenerational reductions in survival and reproduction capacity as well as reinforcement of oviposition avoidance which can contribute as repellent strategies in integrated pest management programs. The transgenerational effects observed suggest a possible reduction both in application frequency and total amount of pesticide used, would help in reducing both control costs and possible ecotoxicological risks.

Floor space and betaine supplementation alter the nutrient digestibility and performance of Japanese quail in a tropical environment.

This study investigated the effects of floor space and betaine supplementation on the nutrient digestibility and performance of laying quail, at an advanced stage of production, in a tropical environment. In total, 408 laying quail (23 weeks old) were distributed in 3 × 2 factorial arrangements with four replicates. The first factor was floor space (250 cm2 [FS-1], 221 cm2 [FS-2], and 200 cm2 per bird [FS-3]) by allocating 15, 17, and 19 birds per cage (cage size: 3750 cm2). The second factor was betaine supplementation, administered at levels of 0 (Control) and 0.12% (Betaine). The birds were housed under a natural, tropical environment that was outside the predominant thermoneutral zone, indicating heat stress conditions. Interactions were found between floor space and betaine on crude fiber digestibility, egg production, and eggshell thickness, with the highest values being yielded in FS-2 group supplemented with betaine. Reducing the floor space to 200 cm2 negatively affected nutrient digestibility and performance. The birds kept in FS-3 had lower (P < 0.05) dry matter, crude protein, crude fat, and calcium digestibility values than those kept in FS-1 and FS-2. Birds housed in FS-2 exhibited higher egg weight than those in FS-3 (P < 0.05), although they did not differ from those in FS-1. Furthermore, a lower eggshell weight in FS-3, compared with FS-1 and FS-2, was observed (P < 0.01). Betaine supplementation enhanced the dry matter, crude protein, crude fat, crude ash, and calcium digestibility values (P < 0.05). Accordingly, betaine improved feed intake, egg weight, feed conversion, and protein and energy efficiency ratios (P < 0.01). Betaine also resulted in higher albumen, yolk, and eggshell weights (P < 0.01). In conclusion, a floor space of 221 cm2, combined with betaine supplementation at 0.12%, can be applied for raising quail under high environmental temperatures.

Embryonic estrogen exposure recapitulates persistent ovarian transcriptional programs in a model of environmental endocrine disruption.

Estrogens regulate key aspects of sexual determination and differentiation, and exposure to exogenous estrogens can alter ovarian development. Alligators inhabiting Lake Apopka, FL, are historically exposed to estrogenic endocrine disrupting contaminants and are characterized by a suite of reproductive abnormalities, including altered ovarian gene expression and abated transcriptional responses to follicle stimulating hormone. Here, we test the hypothesis that disrupting estrogen signaling during gonadal differentiation results in persistent alterations to ovarian gene expression that mirror alterations observed in alligators from Lake Apopka. Alligator embryos collected from a reference site lacking environmental contamination were exposed to estradiol-17 beta or a nonaromatizable androgen in ovo and raised to the juvenile stage. Changes in basal and gonadotropin-challenged ovarian gene expression were then compared to Apopka juveniles raised under identical conditions. Assessing basal transcription in untreated reference and Apopka animals revealed a consistent pattern of differential expression of key ovarian genes. For each gene where basal expression differed across sites, in ovo estradiol treatment in reference individuals recapitulated patterns observed in Apopka alligators. Among those genes affected by site and estradiol treatment were three aryl hydrocarbon receptor (AHR) isoforms, suggesting that developmental estrogen signaling might program sensitivity to AHR ligands later in life. Treatment with gonadotropins stimulated strong ovarian transcriptional responses; however, the magnitude of responses was not strongly affected by steroid hormone treatment. Collectively, these findings demonstrate that precocious estrogen signaling in the developing ovary likely underlies altered transcriptional profiles observed in a natural population exposed to endocrine disrupting contaminants.

[Sugar-Supplemented Substrates Contaminated by Agricultural Inputs Favor the Proliferation of Aedes albopictus (Diptera: Culicidae)]. / Les substrats sucrés contaminés par les intrants agricoles favorisent la prolifération du moustique Aedes albopictus (Diptera : Culicidae).

Originating from South-East Asian tropical forests, Aedes albopictus (Skuse) (Diptera: Culicidae) is a mosquito of great genetic plasticity, which allowed it to adapt to a large variety of environments including the urban ones. Yet many a city nowadays comprises peri urban zones close to land devoted to farming. The sites where Ae. albopictus live and reproduce, located on the fringe of nectarfilled blossoming crops (orchards, colza and sunflower fields) are often polluted by chemical inputs such as fertilizers and pesticides. In this laboratory study we have assessed the impact of sugar-supplemented solutions contaminated by NPK fertilizer and/or by diflubenzuron or pyriproxyfen insecticides on adults of Ae. albopictus mosquitoes. The results have shown that the females feeding on a sweetened solution containing NPK fertilizer laid a significantly greater number of eggs. However when the sweetened solutions contained diflubenzuron or pyriproxyfen insecticides, the actions of both combinations resulted in a noticeable reduction of the numbers of eggs laid and the ones hatching. Finally when the sweetened solutions had been jointly polluted by the fertilizer and either one of the larvicides, the sterilizing effect of the insecticides was completely obliterated regarding both the numbers of eggs laid and the ones hatching. We are led to conclude that the somewhat inconsistent use of pesticides and fertilizers in agriculture bring about new ecological systems favorable to the proliferation of mosquitoes.

Originaire des forêts tropicales d'Asie du Sud-Est, Aedes albopictus (Skuse) (Diptera : Culicidae) est un moustique doté d'une grande plasticité génétique qui lui a permis de s'adapter à des environnements très divers, dont les milieux urbains. Or nombreuses sont les villes aujourd'hui où les quartiers périurbains s'installent à proximité de territoires ruraux à vocation agricole. Lorsque les lieux de vie et de reproduction d'Ae. albopictus se situent en lisière de cultures dont les fleurs sont riches en nectar (à l'exemple des arbres fruitiers, du colza et du tournesol), les adultes mâles et femelles se nourrissent d'exsudats sucrés souvent souillés par des intrants chimiques (engrais et pesticides). Nous avons mesuré dans cette étude de laboratoire, les impacts que généraient des solutions sucrées contaminées par un engrais NPK et/ou par les insecticides diflubenzuron et pyriproxyfen. Les résultats révèlent que lorsque les adultes d'Ae. albopictus absorbent une solution sucrée contenant un engrais NPK, les nombres d'oeufs pondus par les femelles s'en trouvent significativement augmentés. Quand une solution sucrée est au contraire contaminée par les insecticides diflubenzuron ou pyriproxyfen, l'action des deux composés provoque une nette diminution des nombres d'oeufs pondus mais aussi de ceux qui éclosent. Enfin, lorsque les réserves en sucre sont polluées à la fois par l'engrais et l'un ou l'autre des deux larvicides, l'effet stérilisant induit par les deux insecticides disparaît totalement, tant au niveau des nombres d'oeufs pondus que des nombres d'oeufs qui éclosent. Ces observations nous enseignent que l'utilisation pas toujours raisonnée des pesticides et des engrais en agriculture crée des situations écologiques nouvelles, favorables à la pullulation des moustiques.

Influence of particle size of the main cereal of the diet on egg production, gastrointestinal tract traits, and body measurements of brown laying hens1.

The influence of the screen size used to grind the main cereal of the diet on egg production, gastrointestinal tract (GIT) development, and body measurements was studied in hens from 17 to 49 wk of age. Diets formed a 2 × 5 factorial with 2 main cereals (corn vs. barley) and 5 screen sizes of the cereal (4, 6, 8, 10, and 12 mm). Each treatment was replicated 5 times. No interactions between main cereal and screen size were observed for any of the traits studied. Cereal type and screen size did not affect feed intake, egg production, BW gain, or quality traits of the eggs. Eggs tended to be larger (P = 0.092) in hens fed the barley diet than in hens fed the corn diet. Also, feed conversion ratio tended to increase (P = 0.081) when the cereal of the diet was ground with a 4-mm screen as compared with the average of the other diets. At 49 wk of age, the relative weight (% BW) of the GIT and gizzard was greater (P < 0.05) in hens fed barley than in hens fed corn. An increase in the screen size increased linearly the relative weight of the GIT (P = 0.089), gizzard (P < 0.01), and liver (P = 0.056). None of the other GIT traits or body measurements was affected by the main cereal or the screen size. In summary, barley can substitute up to 45% of the corn in diets for laying hens without any adverse effect on egg production. Therefore, the use of one or other cereal will depend on their relative cost. An increase in screen size improved gizzard development but had little effect on hen productivity. Within the range studied, the size of the screen used for grinding the cereal had little effect on hen productivity, although the use of a 4-mm screen might increase feed conversion ratio and gizzard development.

An integrated omic analysis of hepatic alteration in medaka fish chronically exposed to cyanotoxins with possible mechanisms of reproductive toxicity.

Cyanobacterial blooms threaten human health as well as the population of other living organisms in the aquatic environment, particularly due to the production of natural toxic components, the cyanotoxin. So far, the most studied cyanotoxins are microcystins (MCs). In this study, the hepatic alterations at histological, proteome and transcriptome levels were evaluated in female and male medaka fish chronically exposed to 1 and 5 µg L-1 microcystin-LR (MC-LR) and to the extract of MC-producing Microcystis aeruginosa PCC 7820 (5 µg L-1 of equivalent MC-LR) by balneation for 28 days, aiming at enhancing our understanding of the potential reproductive toxicity of cyanotoxins in aquatic vertebrate models. Indeed, both MC and Microcystis extract adversely affect reproductive parameters including fecundity and egg hatchability. The liver of toxin treated female fish present glycogen storage loss and cellular damages. The quantitative proteomics analysis revealed that the quantities of 225 hepatic proteins are dysregulated. In particular, a notable decrease in protein quantities of vitellogenin and choriogenin was observed, which could explain the decrease in reproductive output. Liver transcriptome analysis through Illumina RNA-seq reveals that over 100-400 genes are differentially expressed under 5 µg L-1 MC-LR and Microcystis extract treatments, respectively. Ingenuity pathway analysis of the omic data attests that various metabolic pathways, such as energy production, protein biosynthesis and lipid metabolism, are disturbed by both MC-LR and the Microcystis extract, which could provoke the observed reproductive impairment. The transcriptomics analysis also constitutes the first report of the impairment of circadian rhythm-related gene induced by MCs. This study contributes to a better understanding of the potential consequences of chronic exposure of fish to environmental concentrations of cyanotoxins, suggesting that Microcystis extract could impact a wider range of biological pathways, compared with pure MC-LR, and even 1 µg L-1 MC-LR potentially induces a health risk for aquatic organisms.

Impact of imidacloprid on life-cycle development of Coccinella septempunctata in laboratory microcosms.

Long-term effects of a single application of imidacloprid on ladybird beetle, Coccinella septempunctata L., were studied in indoor laboratory microcosms, starting with the 2nd instar larvae of C. septempunctata but covering the full life cycle. The microcosms comprised enclosures containing a pot with soil planted with broad bean plants and black bean aphid, Aphis craccivora Koch, as food. Exposure doses (0.85-13.66g a.i. ha(-1)) in the long-term microcosm experiment were based on a preliminary short-term (72h) toxicity test with 2nd instar larvae. The measurement endpoints used to calculate NOERs (No Observed Effect application Rates) included development time, hatching, pupation, adult emergence, survival and number of eggs produced. Furthermore, for these endpoints ER50 (application rate causing 50 percent effect) and LR50 (application rate causing 50 percent mortality) values were calculated when possible. The single imidacloprid application affected survival (lowest LR50 4.07g a.i. ha(-1); NOER 3.42g a.i. ha(-1)), egg production (ER50 26.63g a.i. ha(-1)) and egg hatching (NOER 6.83g a.i. ha(-1)). Statistically significant treatment-related effects on the whole development duration, pupation and adult emergence could not be demonstrated (NOER≥13.66g a.i. ha(-1)). The lowest L(E)R50 values and NOERs derived from the laboratory microcosm test with C. septempunctata are lower than the reported field application rates of imidacloprid (15-60g a.i. ha(-1)) in cotton cultivation in China, suggesting potential risks to beneficial arthropods.

Effects of dietary inclusion of lentil byproduct on performance and oxidative stability of eggs in laying quail.

One hundred and sixty-eight 11-week-old laying quails (Coturnix coturnix japonica) were fed one of the following three diets: (1) control: basal diet with no lentil (Lens culinaris L.) byproduct; (2) inclusion of 10% lentil byproduct; (3) inclusion of 20% lentil byproduct. In the recent years, colour sorting machines are used in order to separate red lentils according to their colours. The goal is to select the items which are discoloured, not as ripe as required, or still with hull even after dehulling of lentil seed. During the sorting, a new byproduct called "sorting byproduct" leftover is obtained. The byproduct is cleaner and is of a higher quality than other lentil byproducts. This experiment was conducted to study the effects of the inclusion of different levels of lentil byproduct on laying quail performance. The experimental treatment included 10% or 20% lentil byproduct in the diet, and this was fed to quails aged between 11 and 22 weeks. The inclusion of 10% and 20% levels of lentil byproduct in the diet significantly increased egg production, but feed intake and feed conversion ratio were not significantly affected. Egg weight decreased significantly following the inclusion of 20% lentil byproduct. The inclusion of lentil byproduct in the diet increased the deposition of yellow yolk pigments and decreased malonaldehyde formation in the yolk.