[show abstract][hide abstract] ABSTRACT: The honey bee, Apis mellifera, is frequently used as a sentinel to monitor environmental pollution. In parallel, general weakening and unprecedented colony losses have been reported in Europe and the USA, and many factors are suspected to play a central role in these problems, including infection by pathogens, nutritional stress and pesticide poisoning. Honey bee, honey and pollen samples collected from eighteen apiaries of western France from four different landscape contexts during four different periods in 2008 and in 2009 were analyzed to evaluate the presence of pesticides and veterinary drug residues.
A multi-residue analysis of 80 compounds was performed using a modified QuEChERS method, followed by GC-ToF and LC-MS/MS. The analysis revealed that 95.7%, 72.3% and 58.6% of the honey, honey bee and pollen samples, respectively, were contaminated by at least one compound. The frequency of detection was higher in the honey samples (n = 28) than in the pollen (n = 23) or honey bee (n = 20) samples, but the highest concentrations were found in pollen. Although most compounds were rarely found, some of the contaminants reached high concentrations that might lead to adverse effects on bee health. The three most frequent residues were the widely used fungicide carbendazim and two acaricides, amitraz and coumaphos, that are used by beekeepers to control Varroa destructor. Apiaries in rural-cultivated landscapes were more contaminated than those in other landscape contexts, but the differences were not significant. The contamination of the different matrices was shown to be higher in early spring than in all other periods.
Honey bees, honeys and pollens are appropriate sentinels for monitoring pesticide and veterinary drug environmental pollution. This study revealed the widespread occurrence of multiple residues in beehive matrices and suggests a potential issue with the effects of these residues alone or in combination on honey bee health.
PLoS ONE 01/2013; 8(6):e67007. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: Three beehive matrices, sampled in eighteen apiaries from West France, were analysed for the presence of lead (Pb). Samples were collected during four different periods in both 2008 and 2009. Honey was the matrix the least contaminated by Pb (min = 0.004 μg g(-1); max = 0.378 μg g(-1); mean = 0.047 μg g(-1); sd = 0.057). The contamination of bees (min = 0.001 μg g(-1); max = 1.869 μg g(-1); mean = 0.223 μg g(-1); sd = 0.217) and pollen (min = 0.004 μg g(-1); max = 0.798 μg g(-1); mean = 0.240 μg g(-1); sd = 0.200) showed similar levels and temporal variations but bees seemed to be more sensitive bringing out the peaks of Pb contamination. Apiaries in urban and hedgerow landscapes appeared more contaminated than apiaries in cultivated and island landscapes. Sampling period had a significant effect on Pb contamination with higher Pb concentrations determined in dry seasons.
[show abstract][hide abstract] ABSTRACT: Low-consistency, high-moisture feces have been observed in large dogs (Canis lupus familiaris), compared with small dogs, and particularly in sensitive breeds (e.g., German Shepherd dogs). The aim of this work was to determine if greater colonic protein fermentation is responsible for poorer fecal quality in large sensitive dogs. Twenty-seven bitches were allotted to 4 groups based on size and digestive sensitivity: small, medium, large tolerant, and large sensitive. Five experimental diets varying in protein source [highly digestible wheat gluten (WG) vs. medium digestible poultry meal (PM), and protein concentration from 21.4 to 21.6 (LP) to 38.2 to 39.2% CP (HP)] were tested. Diets were fed for 14 d and followed by a 12-d transition period. Digestive fermentation by-products were investigated in fresh stools [ammonia, phenol, indole, and short chain fatty acids including acetate, propionate, and butyrate (C2 to C4 SCFA), branched-chain fatty acids (BCFA), and valerate] and in urine (phenol and indole). Bacterial populations in feces were identified. The PM diets resulted in greater fecal concentrations of ammonia, BCFA, valerate, indole, and C2 to C4 SCFA than WG diets (P = 0.002, P < 0.001, P = 0.039, P = 0.003, and P = 0.012, respectively). Greater concentrations of ammonia, BCFA, and valerate were found in the feces of dogs fed HP compared with LP diets (P < 0.001, P < 0.001, and P = 0.012, respectively). The concentrations of ammonia, valerate, phenol, and indole in feces of large sensitive dogs were greater (P < 0.001, P < 0.001, P = 0.002, and P = 0.019, respectively) compared with the other groups. The Enterococcus populations were greater in feces of dogs fed with PMHP rather than WGLP diets (P = 0.006). Urinary phenol and indole excretion was greater when dogs were fed PM than WG diets (P < 0.001 and P = 0.038, respectively) and HP than LP diets (P = 0.001 and P = 0.087, respectively). Large sensitive dogs were prone to excrete a greater quantity of phenol in urine (P < 0.001). A diet formulated with highly digestible protein, such as WG, led to reduced concentrations of protein-based fermentation products in feces together with improved fecal quality in dogs, especially in large sensitive ones. Poor fecal quality in large sensitive dogs could be partly related to the pattern of protein fermentation in the hindgut.
Journal of Animal Science 02/2012; 90(8):2570-80. · 2.09 Impact Factor
[show abstract][hide abstract] ABSTRACT: Three beehive matrices, sampled in six different apiaries from West France, were analyzed for the presence of four polycyclic aromatic hydrocarbons (PAH4: benzo[a]pyrene, benzo[a]anthracene, benzo[b]fluoranthene and chrysene). Samples were collected during four different periods in both 2008 and 2009. Honey samples showed the lowest levels of PAH4 contamination (min=0.03 μg kg(-1); max=5.80 μg kg(-1); mean=0.82 μg kg(-1); Sd=1.17). Bee samples exhibited higher levels of PAH4 contamination (min=0.32 μg kg(-1); max=73.83 μg kg(-1); mean=7.03 μg kg(-1); Sd=17.83) with a great dispersion of the concentrations due to four main events of high concentrations. Pollen samples showed only one major episode with the highest PAH4 concentration found (min=0.33 μg kg(-1); max=129.41 μg kg(-1); mean=7.10 μg kg(-1); Sd=22.28). The PAH4 concentrations found were significantly influenced by the landscape context for all beehive samples.
[show abstract][hide abstract] ABSTRACT: The direct vasodilatory action of pentoxifylline (1-(5-oxohexyl)-3,7-dimethylxanthine) and its signalling pathway was evaluated in equine digital veins. Cumulative concentration-response curves to pentoxifylline (1 nM to 300 μM) were recorded in phenylephrine-precontracted equine digital vein rings under different experimental conditions. Relaxation to pentoxifylline was partially inhibited by endothelium removal, but was unaltered by CGS-15943 (a non-xanthine adenosine receptor antagonist; 3 μM). Nitric oxide synthase (NOS), soluble guanylate cyclase and cyclooxygenase (COX) inhibitors (Nω-nitro-L-arginine methyl ester (100 μM), ODQ (30 μM) and indomethacin (10 μM), respectively) significantly reduced the maximum relaxation induced by pentoxifylline. Moreover, pentoxifylline-induced relaxation was strongly reduced by Rp-8-Br-PET-cyclic guanosine monophosphate-S (a protein kinase G inhibitor; 3 μM), but remained unaffected by H-89 (a protein kinase A inhibitor; 2 μM). Pentoxifylline-induced relaxation was associated with a 3.4-fold increase in tissue cGMP content. To investigate whether pentoxifylline can affect cAMP- and cGMP-mediated relaxations, curves to forskolin, to sodium nitroprusside (SNP) and 8-bromo-cGMP were also recorded in endothelium-denuded equine digital vein rings pretreated with pentoxifylline (10 and 100 μM). Pentoxifylline only potentiated the SNP-mediated relaxation at the highest concentration (100 μM). Thus, pentoxifylline relaxed equine digital veins via endothelium-dependent and endothelium-independent components. The effect was mediated through both the NOS and COX pathways and could also result from inhibition of cGMP specific-phosphodiesterase activity at the highest concentrations used.
The Veterinary Journal 10/2011; 192(3):368-73. · 2.42 Impact Factor
[show abstract][hide abstract] ABSTRACT: The occurrence and severity of obesity- and insulin resistance-related disorders vary according to the diet. The aim of the present longitudinal study was to examine the effects of a high-fat or a high-fructose diet on body weight (BW), body fat mass, insulin sensitivity (IS) and lipid profiles in a rat model of dietary-induced obesity and low IS. A total of eighteen, 12-week-old male Wistar rats were divided into three groups, and were fed with a control, a high-fat (65 % lipid energy) or a high-fructose diet (65 % fructose energy) for 10 weeks. BW, body fat mass ((2)H2O dilution method), IS (euglycaemic-hyperinsulinaemic clamp technique), plasma glucose, insulin, NEFA, TAG and total cholesterol were assessed before and at the end of 10-week period. Cholesterol was measured in plasma lipoproteins separated from pooled samples of each group and each time period by using fast-protein liquid chromatography. All rats had similar BW at the end of the 10-week period. Body fat mass was higher in the high-fat group compared to the control group. There was no change in basal glycaemia and insulinaemia. The IS was lower in the high-fat group and was unchanged in the high-fructose group, compared to the control group. Plasma TAG concentration and cholesterol distribution in lipoproteins did not change over time in any group. Plasma NEFA concentration decreased, whereas plasma TAG concentration increased over time, regardless of the diet in both cases. The 10-week high-fat diet led to obesity and low IS, whereas rats fed with the high-fructose diet exhibited no change in IS and lipidaemia. The high-fat diet had more deleterious response than high-fructose diet to induce obesity and low IS in rats.
The British journal of nutrition 10/2011; 106 Suppl 1:S206-10. · 3.45 Impact Factor
[show abstract][hide abstract] ABSTRACT: The aim of this in vitro study was to compare the uterokinetic activity of oxytocin and dinoprost, the natural PGF2α, with or without aglepristone, in canine myometrial fibers. Thirty-three bitches were allocated into one of four groups, depending on their estrous stage and whether or not they had received a treatment with aglepristone (metestrus aglepristone, n = 5; metestrus without treatment, n = 9; anestrus aglepristone, n = 9; anestrus without treatment, n = 10). After hysterectomy, longitudinal and circular uterine strips were mounted in organ baths. Oxytocin or PGF2α (10 nmol/l to 10 micromol/l) were applied non-cumulatively. A linear mixed effects models theory was used to compare the fiber effect, the aglepristone effect, and the treatment effect, from the area under the curves calculated from the contractile effect/concentration curves for each drug. Oxytocin and PGF2α induced concentration-dependent myometrial contractions in longitudinal (LF) and circular myometrial fibers (CF), indicating the presence of functional contractile oxytocin- and PGF2α-receptors in metestrus and anestrus. The contractile response to oxytocin was greater in LF than in CF in all of the groups; the response to PGF2α was greater in LF than in CF in non-treated bitches in anestrus and in treated bitches in metestrus. These results suggest that there is a difference in sensitivity or a heterogeneous distribution of oxytocin and PGF2α-receptors in the myometrial layers, which is independent of hormonal impregnation. The contractile response to oxytocin and PGF2α was significantly increased after aglepristone treatment in LF during metestrus, suggesting that the progesterone withdrawal induced by aglepristone has a role to play. The longitudinal myometrial layer also appeared to be the target for the two drugs at this stage. This study provides new information about canine uterine contractile activity, notably the differing behavior of myometrial CF and LF; in vivo studies are required to test the use of a combination of aglepristone and oxytocin in the treatment of canine pyometra.
[show abstract][hide abstract] ABSTRACT: An extender has been developed with low-density lipoproteins (LDLs) that eliminates the microbial risks associated with the use of whole egg yolk. The objective of this study was to assess the effects of substituting egg yolk with LDLs for use as an extender in sperm preservation at 4 °C, as well as on spermatozoa motility, plasma membrane and acrosome integrity, at two different concentrations (80×10(6) and 240×10(6) sperm per ml) for 8 days and to evaluate glycerol toxicity in both extenders. A total of 12 ejaculates were collected from three bulls. Spermatozoa motility was examined using computer-assisted semen analysis. Plasma membrane integrity was determined using the hypo-osmotic swelling test and acrosome integrity with the fluorescein isothiocyanate-Pisum sativum agglutinin test. The semen was subsequently divided into four aliquots and diluted with Tris-egg yolk-glycerol (TEG), Tris-egg yolk without glycerol (TE), LDL with glycerol (LDL(+)) and LDL without glycerol (LDL(-)), at 80×10(6) and 240×10(6) sperm per ml. This study showed that the LDL(+) and LDL(-) extenders were more effective at preserving spermatozoa motility, plasma membrane integrity and acrosome integrity than TEG and TE (P<0.05) during 8 days of incubation. After 3 days of incubation, a toxicity of glycerol was observed in TEG, whereas no significant difference was observed between LDL(+) and LDL(-). We can therefore conclude that the LDL extender can be used to refrigerate semen at 4 °C instead of TEG and TE at 80×10(6) and 240×10(6) sperm per ml for elite bulls. This finding can be used to define a policy for the storage of high-quality bull semen.
Asian Journal of Andrology 11/2010; 13(2):281-6. · 2.14 Impact Factor
[show abstract][hide abstract] ABSTRACT: A semen extender made with low density lipoproteins (LDL) has been used instead of a standard extender that is already available on the market for the cryopreservation of bovine semen. However, in order to extend its use to artificial insemination centres, in vivo fertility studies were required. Semen was taken from three bulls and frozen-thawed in two extenders: the LDL extender and a standard Tris-egg-yolk (20%) extender used by AI centres. The quality of the semen was assessed prior to artificial insemination: motility was assessed using an image analyser (Computer Assisted Semen Analysis (Hamilton Thorne)), and the integrity of the plasma membrane was assessed using the hypo-osmotic test (HOS test). For the first time, gestations were obtained following the artificial insemination of cows in the field (n=193) with semen that had been frozen-thawed in the LDL extender. No significant difference (p>0.05) was detected between the success rates of AI between the semen that had been frozen-thawed in the LDL extender (59.2%) and the control extender, Tris-20% egg yolk (65.3%). In conclusion, the in vivo fertility of semen that has been frozen-thawed in the LDL extender is maintained since gestations are obtained following AI.
[show abstract][hide abstract] ABSTRACT: In experimental pharmacology, drug effect studies currently establish and analyse cumulative concentration-response curves (CCRC) under repeated measurements designs. Usually the CCRC parameters are estimated using the Hill's function in a nonlinear regression for independent data. The two-way analysis of variance is generally used to identify a statistical difference between the responses for two treatments but that analysis does not take into account the nonlinearity of the model and the heteroscedasticity (uneven distribution) of the data. We presently tested the possibility of finding a statistical solution for the nonlinear response in repeated measurements data using the nonlinear mixed effects (nlme) models.
Experimental data sets, originating from studies on beta-adrenoceptor-induced relaxation in rat thoracic aorta ring, were analysed using the nlme methods.
Comparison with classical methods showed the superiority of the nlme models approach. For each pharmacological parameter (E(m), n, pD(2)), a point estimate, a standard error and a confidence interval are returned by the nlme procedures respecting the assumption of independency and normality of the residuals.
Using the method presently described, it is now possible to detect significant differences for each pharmacological parameter estimated in different situations, even for designs with small samples size (i.e. at least six complete curves).
The Journal of pharmacy and pharmacology. 03/2010; 62(3):339-45.
[show abstract][hide abstract] ABSTRACT: In experimental pharmacology, studies on drug-receptor interactions commonly use dose-response curves (DRC) established under repeated measurements designs. The best approach to analyse a dose- response relationship is to use non linear mixed effects models (nlme) (Davidian and Giltinian, 1995), but specific softwares dedicated to analyse pharmacological data have not yet developped nlme procedures. The aim of this work was to provide accurate and easy-to-use tools on R to assist pharmacologists with using nlme modelling to fit DRC. Five functions using available R packages have been built. The Est.Pop function, using nlme function in nlme package (Pinheiro and Bates, 2000), gives an estimation of the different parameters included in the predicted function and a qqplot of the residuals. The IC.par function provides a confidence interval for each parameter of the predicted function for the confidence level asked by users. The Graph.curves function displays a graph showing the individual fitted curves and the population fitted curve which illustrate the individual effect on physiological response. Nevertheless, nlme procedures are very susceptible to outliers points in the data sets and the convergence of the iterative calculus is not always achieved. In those situations and when the residuals seem not to be normally distributed the Est.Boot function is more accurate to give an estimation of the predicted function parameters by a non parametric bootstrap method using the bootstrap package (Huet et al, 2004). Depending on the bioassay and the relative asymmetry of the curves, four predictive functions (Hill equation, Richards, Gompertz, Hill modified functions) can be tested (Giraldo et al, 2002) with those tools; the Comp.Mod function is dedicated to compare established models and to detect the best one.
[show abstract][hide abstract] ABSTRACT: Oxolinic acid, flumequine, oxytetracycline, and florfenicol are antibiotics commonly used in farming. Because an important percentage of these antibiotics given to fish and cattle ends up, directly or indirectly, in the freshwater environment, suitable tools for the monitoring of these antibiotics are needed. A French river was chosen because of the location of four fish farms and a sewage plant on its main course. First, a passive monitoring program involving water, sediment, and autochthonous bryophytes was performed at 25 sampling sites tested once every three months for one year. Second, an active monitoring method was performed using moss bags for a one-month exposure period, both upstream and downstream of each potential source of antibiotics. Sediment and bryophyte samples, but not water samples, were found to be useful for monitoring environmental contamination by oxolinic acid, flumequine, oxytetracycline, and florfenicol. Sediments and bryophytes also appeared to be complementary media for dating the river's contamination by antibiotics. Data collected by both active and passive monitoring methods confirmed contamination of the river, mainly by flumequine and oxytetracycline, attributable to fish farming but also to terrestrial animal farming and perhaps human pharmaceuticals.
Environmental Toxicology and Chemistry 12/2008; 28(3):496-502. · 2.62 Impact Factor
[show abstract][hide abstract] ABSTRACT: The presence of anti-microbial-resistant bacteria in the aquatic environment remains a matter of concern for environmental, animal and human health risks. Many published data have reported increased anti-microbial resistance among the aquatic microbiota from fish farm environments which often coincides with the use of anti-microbial agents. It can be assumed that the selection of anti-microbial-resistant bacteria first occurs in the fish farms themselves, at locations where anti-microbial concentrations are active. As anti-microbial agents are frequently administered through feed pellets, faecal matter excreted could favour conditions for such selection. In this study, OA (oxolinic acid) concentrations and OA resistance of Aeromonads were surveyed in output water and in faecal matter from OA medicated (test) and non-medicated (control) fish tanks during and after an OA oral treatment. Because of the low counts of Aeromonads in the output water, it was not possible to obtain reliable data on the proportion of anti-microbial resistance in this compartment. On the other hand, a time-limited effect on the abundance of Aeromonads isolated from faecal matter was only observed in test tanks. In these tanks, high proportion (80-100%) of OA-resistant Aeromonads was present in deposited faecal matter until at least one week after the end of the anti-microbial treatment. At that time OA was no longer detected within the faecal matter, after having reached concentrations between 100 and 190 mu g/g during the treatment. We discuss how the leaching of OA from faecal pellets, from the intestine to their deposit, may favour the selection of OA-resistant Aeromonads. Further investigations in real conditions on microbiota associated with faecal matter in transit through the fish farm system are required. Particular attention should be paid to the wastes collected by the filter treatments of fish farm effluents. (C) 2007 Elsevier B.V. All rights reserved.
[show abstract][hide abstract] ABSTRACT: The purpose of this work was to investigate the interest of rabbits for studying pharmacology and toxicology of dietary nitrate. Twenty-one females were given 1, 300 and 600mg/l nitrate in drinking water for 11 weeks. Saliva and blood were analysed for nitrate/nitrite. There is a linear relationship between the amounts of nitrate ingested and amount of nitrate in saliva, contrary to what is observed in rats. However, salivary nitrite concentrations remain low, and nitrate reductase activity in the oral cavity of the rabbit seems very weak.
Environmental Toxicology and Pharmacology 01/2007; 23(1):132-4. · 2.01 Impact Factor
[show abstract][hide abstract] ABSTRACT: To determine the effect of oxolinic acid (OA) dosage treatment on the selection of antibiotic-resistant bacteria in fanned trout, three different dosages of OA were administered over seven consecutive days, via medicated feed, to healthy rainbow trout reared in experimental tanks supplied with river water. OA dosage licensed in France (12 mg/kg/day), over-dosage (24 mg/kg/day) and under-dosage (6 mg/kg/day) were tested. The importance of trout gut and rearing waters as potential sites of selection for antibiotic-resistant bacteria in fish fanning were investigated (i) by quantification of heterotrophic microbiota on GSP selective medium and of motile Aeromonas on TSA medium, and (ii) by characterisation of Aeromonas OA susceptibility levels before, during and until two weeks after treatment. In the intestines of treated and control fish, bacterial counts were severely reduced during the entire experiment, and Aeromonas populations remained susceptible to OA. In contrast, bacterial counts in output water of both medicated and control tanks were significantly higher than in input water. OA minimum inhibitory concentration distributions of Aeromonas estimated with a replica plating method (GSP plates supplemented with OA concentrations from 0.03 mg/l to 2 mg/l) indicated that the treatment, whatever the dosage, had induced the emergence of OA-resistant Aeromonas in output water. OA MIC of resistant Aeromonas isolated on GSP agar (estimated MIC >= 4 mg/l) determined using an agar dilution method on Mueller-Hinton agar confirmed the presence in output water of highly OA-resistant Aeromonas (MIC >= 128 mg/l). Between one and two weeks after the end of treatment, those highly OA-resistant Aeromonas were all the more prevalent among total Aeromonas populations that treatment dosage was higher. Results suggested that selection and emergence of OA-resistant Aeromonas had probably occurred in faecal matters after excretion, rather than in the fish intestines. (C) 2007 Elsevier B.V. All rights reserved.
[show abstract][hide abstract] ABSTRACT: The consequences of antibiotic use in aquatic integrated systems, which are based on trophic interactions between different cultured organisms and physical continuity through water, need to be examined. In this study, fish reared in a prototype marine integrated system were given an oxolinic acid treatment, during and after which the level of resistance to this quinolone antibiotic was monitored among vibrio populations from the digestive tracts of treated fish, co-cultured bivalves and sediments that were isolated on thiosulfate-citrate-bile-sucrose. Oxolinic acid minimum inhibitory concentration distributions obtained from replica plating of thiosulfate-citrate-bile-sucrose plates indicated that a selection towards oxolinic acid resistance had occurred in the intestines of fish under treatment. In contrast, and despite oxolinic acid concentrations higher than minimum inhibitory concentrations of susceptible bacteria, no clear evolution of resistance levels was detected either in bivalves or in sediments.
[show abstract][hide abstract] ABSTRACT: Low-density lipoproteins (LDL) have been previously isolated and identified as the cryoprotective fraction of yolk. The effect of LDL on sperm motility after freezing-thawing has been reported, but no study has been made to assess the effect of LDL on bull semen fertility. The aim of this study was to evaluate the fertility of bull semen cryopreserved in the presence of LDL. Motility of semen cryopreserved in LDL was analyzed and compared to semen cryopreserved with Optidyl, a commercial extender containing egg yolk. To evaluate the fertilizing ability of semen, we used in vitro fertilization test, whereas acrosome and plasma membrane integrity were also evaluated. The percentage of motile spermatozoa was two fold higher after freezing in LDL than in Optidyl 54.4% versus 30.2% (P < 0.05). The cleavage rate was significantly higher after fertilization with semen frozen in LDL than with Optidyl 63.0% versus 54.8% (P < 0.05). No significant difference was observed on the blastocyst rate after in vitro culture. Integrity of the acrosome and the plasma membrane were maintained in both extenders. In conclusion, LDL preserve bull semen quality and fertilizing ability, allowing also better semen motility, after the freeze-thaw process.