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1.
Red mite field populations from seven naturally infested Italian caged laying poultry farms were investigated for their susceptibility to acaricide formulations available on the market, containing amitraz, carbaryl and permethrin. A minimum of 3,000 mites of all stages were collected from each farm and were tested with five acaricide concentrations (5, 10, 20, 50, 100%) plus an untreated control (0%). Field red mite populations were found to be tolerant even with the highest concentrations with carbaryl and permethrin for six (86%) and three (42%) of the investigated farms, respectively (< 0.05). Furthermore, six (86%) of the investigated farms showed a red mite population susceptible to amitraz at any concentration. Out of the seven field populations tested with amitraz, one population is becoming less tolerant whereas another was the most tolerant to carbaryl and permethrin at any concentration. Data show that the lack of effectiveness of some acaricides is spreading in Europe and call for the adoption of alternative management strategies to avoid development of resistance.  相似文献   

2.
The relative toxicities of ten acaricides to northern fowl mite,Ornithonyssus sylviarum (Canestrini and Fanzago), and the chicken mite,Dermanyssus gallinae (De Geer), were determined simultaneously by holding the mites inside disposable glass Pasteur pipettes previously immersed in acetone solutions of various concentrations (w/v) of technical grade acaricides. The LC90s (parts per million) of the acaricides after 24 h exposure for the northern fowl mite and the chicken mite, respectively, were: bendiocarb (13.1, 0.18), tetrachlorvinphos (14.5, 4.07), carbaryl (15.0, 0.83), pirimiphos methyl (18.3, 2.03), permethrin (23.1, 8.46), lambda cyhalothrin (80.7, 11.4), dichlorvos (252.8, 3.75), malathion (238.4, 6.59), amitraz (6741, 9430) and fenvalerate (>10000, 60.2). After 48 h exposure there were only slight increases in mortalities of both species except for increased mortalities for the northern fowl mite with lambda cyhalothrin, amitraz and fenvalerate, and for the chicken mite with amitraz.  相似文献   

3.
The objective of this study was to investigate whether zinc, along with pyridoxine, is effective in improving performance and egg quality of laying hens. One hundred and twenty, 28-week-old Hy-Line laying hens were assigned to four treatment groups, 30 hens each. The birds were fed a basal diet or the basal diet supplemented with either 30 mg of zinc/kg of diet, 8 mg of pyridoxine/kg of diet, or 30 mg of zinc plus 8 mg of pyridoxine/kg of diet. Feed conversion (P < 0.01) and egg production (P < 0.01) improved most when both zinc and pyridoxine were supplemented to the diet. Eggshell weights were also greatest (P < 0.01) when the diet was supplemented with both pyridoxine and zinc. Egg-shape index was, however, greatest with zinc-supplemented diet (P < 0.004). Haugh unit was greatest in eggs of hens fed a diet supplemented with both zinc and pyridoxine (P < 0.01). Dietary zinc and pyridoxine supplementations together increased plasma calcium and phosphorous concentrations (P < 0.002). The results of the present study suggested that zinc (30 ppm) and pyridoxine (8 ppm) supplements, when used together, are recommended in terms of a better performance and egg quality in laying hens.  相似文献   

4.
Permethrin as a topical acaricide cream is widely used to treat scabies. The neuronal voltage-sensitive sodium channel (Vssc), necessary for the generation of action potentials in excitable cells, is the target of pyrethroid acaricides such as permethrin. Pyrethroid resistance has been linked to specific mutations in the Vssc gene. Following the partial sequencing of the Vssc gene in the scabies mite Sarcoptes scabiei (L.) (Astigmata: Sarcoptidae), we compared Vssc gene sequences from permethrin-sensitive and -tolerant S. scabiei var. canis Gerlach mites, and identified a G to A single nucleotide polymorphism (SNP) in permethrin-tolerant mites resulting in an amino acid change from glycine to aspartic acid in domain III S6. The mutation is in a region of the gene where mutations have been identified in a range of pyrethroid-resistant arthropods. Results of in vitro permethrin exposure assays showed that survival rates for mites bearing the mutation were similar to those previously reported for mites from human subjects where clinical tolerance to permethrin had been observed. A real-time polymerase chain reaction-high-resolution melt (PCR-HRM) assay was developed to detect this SNP. This assay provides a useful methodology for screening for this and other mutations associated with permethrin resistance in scabies mite populations and thus facilitates surveillance for acaricide resistance.  相似文献   

5.
Toxicity was determined for 15 acaricides against a laboratory strain of northern fowl mites,Ornithonyssus sylviarum (Canestrini and Fanzago). Adult females were exposed to residues on filter paper for 24 h. Three organophosphorous compounds (monocrotophos, cythioate, and famphur) were more toxic to the northern fowl mite than was carbaryl, the most commonly used pesticide in the poultry industry. The other tested compounds were less toxic to the mite than was carbaryl. Four of these, not used previously for northern fowl mite control, had low LC50's for northern fowl mites: aldicarb (0.46); pirimiphos-methyl (0.73); exo, exo-2,8-dichloro-4-thiatricyclo [3.2.1.03.6]octane-4-oxide (AI3-63182) (0.87); and diazinon (2.48).This article reports the results of research only. Mention of a pesticide or proprietary product does not constitute an endorsement or a recommendation of its use by U.S.D.A.  相似文献   

6.
Ammonia gas is one of the most abundant aerial pollutants of modern poultry buildings. The current chronic exposure limit for ammonia of 25 ppm is set for human safety rather than animal welfare. This study assessed the behavioural preferences of laying hens (Gallus gallus domesticus) for different concentrations of ammonia found in commercial poultry houses. Six groups, each of six laying hens, were given the choice of three concentrations of ammonia ( approximately 0, 25 and 45 ppm) in a preference chamber over a period of 6 days and their location and behaviour recorded every 15 min. Hens foraged (p=0.018), preened (p=0.009) and rested (p=0.029) significantly more in fresh air than in the ammonia-polluted environments. There was a significant difference between the responses in 0 and 25 ppm (p<0.05) but not between 25 and 45 ppm (p>0.05). This suggests that ammonia may be aversive to hens with a threshold for this aversion between 0 and 25 ppm. Future studies should explore graded concentrations of ammonia between 0 and 25 ppm in order to suggest a new chronic exposure limit on the basis of animal welfare.  相似文献   

7.
Currently, the most efficient and widely used method of tick control still is the treatment with acaricides, especially permethrin (active ingredient of the Advantage® Max3, Bayer), a pyrethroid with neurotoxic action. Due to the wide use of this acaricide in the control of the tick Rhipicephalus sanguineus, this study carried out laboratorial procedures to determine the LC50 (lethal concentration fifty) of permethrin in semi-engorged females of R. sanguineus. Based on the result of 14 dilutions of permethrin in distilled water and later Probit analysis, the LC50 of permethrin for R. sanguineus was 2062 ppm (1549-2675 ppm). This work can be used as a protocol with other chemicals, to determinate the LC50, basic procedure for studies of control, resistance and behavior of ticks treated with acaricides, especially the brown dog tick R. sanguineus. Also, the knowledge of the LC50 provides information on the potency of chemicals, the sensitivity of Arthropods to them and even estimates on pest control.  相似文献   

8.
Results of a 2-year (2009–2010) survey on the occurrence of ochratoxin A (OTA) in swine feed and in feed for laying hens in Portugal are reported. A total of 664 samples (478 swine feed, 186 feed for laying hens) were analyzed by a HPLC method using fluorescence detection with 2 μg kg?1 as detection limit. In swine feed, 31 samples (6.49%) were positive for OTA. In feed for laying hens, 12 samples (6.45%) were OTA-positive. The average levels of contamination were low, with median values of positive samples at 3–4 μg kg?1 in both years and both commodities, although a few samples contained exceptionally high levels (maximum 130 μg kg?1). Only the maximum level sample (swine feed) contained OTA at a concentration exceeding the European Commission guidance value. The remaining OTA concentrations found in feed samples were much lower than the guidance values.  相似文献   

9.
1. A comparative study on the iron content in internal organs (blood, liver, spleen, kidneys and heart), carcass and feathers, as well as on the whole iron content has been carried out at different ages (4, 8, 13, 18 and 24 weeks), on two chicken breeds (shaver and New Hampshire). 2. The iron content in internal organs in shaver was higher than in New Hampshire. 3. A tendency of the iron content in the carcass to decrease with age has been observed for both breeds; values were higher for laying shaver hens. 4. The egg-producing strain, shaver, showed a greater iron status with a stable body iron content from 13 weeks on (53-55 ppm), permitting a constant laying frequency (90%) during an 18-month period, with only a small reduction of egg iron content from 33.8 to 31 ppm. 5. The whole body iron decreased progressively with age in the New Hampshire broiler strain to 42-49 ppm iron, and the laying process sharpened this tendency. A drastic reduction in laying, accompanied by a lower egg iron content (28.9 ppm iron), was observed. 6. Iron data obtained in the present paper reflect the specific genetic adaptation to egg production of the shaver strain.  相似文献   

10.
The role of macrophages in the function of the hen ovary has not yet been described, although these cells may be an important regulator of ovarian function in mammals. The aim of this study was to determine the changes in the frequency of macrophages during ageing and follicular atresia, and the effects of sex steroids on the macrophage population in the hen ovary. Cryostat sections of ovarian tissues of immature, young laying and old laying hens and those of immature hens treated with or without diethylstilboestrol (DES) or progesterone were immunostained for macrophage cells using mouse anti-chicken macrophage monoclonal antibody. Macrophages were observed under a light microscope and counted using a computer assisted image analyser. The frequency of macrophages in both the stroma and theca of primary follicles was significantly greater in young laying hens than in immature and old laying hens and these cells were more frequent in old laying hens than in immature hens (P < 0.01). Macrophages were more frequent in atretic follicles than in normal follicles (P < 0.01). The number of macrophages in both the stroma and theca of primary follicles of DES-treated birds was significantly greater than in those of progesterone-treated and control birds (P < 0.01). Progesterone had no significant effect on the population of macrophages. These results suggest that macrophages in the ovary increase in association with sexual maturation of birds and atresia of follicles and decrease during ageing. Oestrogen may be one of the factors that affect the population of macrophages in the hen ovary.  相似文献   

11.
Typhlodromus pyri, reared on plate cultures and fed on pollen of Vicia faba, were bioassayed using a taped-slide technique. Mite stocks from isolated unsprayed orchards were used to establish base-line susceptibility to azinphos-methyl, parathion, carbaryl and permethrin. Stocks from English orchards with a spray history of organophosphates and carbaryl showed resistance of 4 to 6x to azinphos-methyl, c 50 x to parathion, >20x to carbaryl, and no resistance to permethrin. An orchard population derived from T. pyri imported from New Zealand in 1977 responded similarly. In other tests, mites exposed to spray residues on glass and on apple leaves were killed by lower concentrations than in taped-slide tests (glass < apple leaf < taped-slide technique); but for all three assay techniques the resistance factors to azinophos-methyl and carbaryl, comparing two stocks, were similar. All stocks from sprayed orchards were resistant to both azinphos-methyl and carbaryl, suggesting cross-resistance; and resistance to both these pesticides appeared to be stable in the field when selection pressure was relaxed. The results are discussed in relation to earlier work on T. pyri and two other resistant orchard-inhabiting phytoseiid species.  相似文献   

12.
Northern fowl mites were monitored on a caged-layer operation in southern California for 22 mo. Three experienced observers underestimated actual numbers of mites in the vent region approximately 80% of the time. Errors were higher for heavy infestations. Observer estimates were highly correlated with each other (r > 0.89, P < 0.01) and with mite numbers estimated by vent feather removal (r > 0.82, P < 0.01). Mites on hens varied between houses and over time. Molting consistently reduced mite numbers, but did not eliminate then in a flock. Long-term monitoring of individual sentinel hens demonstrated that some hens would support high numbers of mites for several months or more. Use of a new sequential hen sampling plan required approximately 1 min per hen, if mite numbers were estimated. At this site, treatment decisions often could be reached in < 20 min per house. Mite scores (index of estimated mites per hen) were well correlated with percentage of hens infested in both test houses. In a chronically infested house, prevalence of mites on eggs averaged 8.5%, with a range of 0-55%. Applications of tetrachlorvinphos-dichlorvos by the producer appeared to be based on mites on > about 20% of eggs. The chemical was marginal for controlling mites on hens (25% reduction in percentage of hens infested), but effectively reduced mites on eggs (95% fewer mites on eggs at 1 wk and 90% at 2 wk). When data were grouped by mite index score on hens, there was a strong relationship (r2 = 0.83, P < 0.01) between mite prevalence on eggs and the scores of the hens which laid them. Sampling 100 eggs evenly spaced in a house required < 7 min, and adult mites were easily seen. Sampling mites on eggs appears to be useful to localize at least high-level infestations, and egg-based sampling for mites merits further investigation.  相似文献   

13.

Background

Recent declines in honey bees for crop pollination threaten fruit, nut, vegetable and seed production in the United States. A broad survey of pesticide residues was conducted on samples from migratory and other beekeepers across 23 states, one Canadian province and several agricultural cropping systems during the 2007–08 growing seasons.

Methodology/Principal Findings

We have used LC/MS-MS and GC/MS to analyze bees and hive matrices for pesticide residues utilizing a modified QuEChERS method. We have found 121 different pesticides and metabolites within 887 wax, pollen, bee and associated hive samples. Almost 60% of the 259 wax and 350 pollen samples contained at least one systemic pesticide, and over 47% had both in-hive acaricides fluvalinate and coumaphos, and chlorothalonil, a widely-used fungicide. In bee pollen were found chlorothalonil at levels up to 99 ppm and the insecticides aldicarb, carbaryl, chlorpyrifos and imidacloprid, fungicides boscalid, captan and myclobutanil, and herbicide pendimethalin at 1 ppm levels. Almost all comb and foundation wax samples (98%) were contaminated with up to 204 and 94 ppm, respectively, of fluvalinate and coumaphos, and lower amounts of amitraz degradates and chlorothalonil, with an average of 6 pesticide detections per sample and a high of 39. There were fewer pesticides found in adults and brood except for those linked with bee kills by permethrin (20 ppm) and fipronil (3.1 ppm).

Conclusions/Significance

The 98 pesticides and metabolites detected in mixtures up to 214 ppm in bee pollen alone represents a remarkably high level for toxicants in the brood and adult food of this primary pollinator. This represents over half of the maximum individual pesticide incidences ever reported for apiaries. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the effects of these materials in combinations and their direct association with CCD or declining bee health remains to be determined.  相似文献   

14.
This study was performed to determine the effects of copper proteinate on performance, blood chemistry, lipid peroxidation status, and organs as well as copper deposition in the liver and eggs of laying hens. Seventy-two 30-week-old Bovans laying hens were distributed into four groups with three replicates. Animals were fed basal diet containing at least 17% crude protein and 2,800 kcal/kg metabolizable energy supplemented with either 0, 150, 300, or 450 mg/kg copper as copper proteinate. Supplementation of 150 and 300 mg/kg copper increased egg production, whereas 450 mg/kg copper decreased (p < 0.001). Liver copper levels were elevated in 300 and 450 mg/kg copper-supplemented groups (p < 0.001). Egg copper contents increased in all treatment groups (p < 0.01). An increase in glucose (p < 0.001) and decreases in albumin (p < 0.01) and total cholesterol (p < 0.05) levels were determined with 300 and 450 mg/kg copper. Supplementation of 450 mg/kg copper increased alkaline phosphatase and gamma glutamyl transpeptidase activities (p < 0.05), malondialdehyde, and high-density lipoprotein levels (p < 0.01) but decreased alanine aminotransferase and lactate dehydrogenase activities (p < 0.01). No gross and microscopic changes were observed in the liver and kidneys. These results indicated that 150 and 300 mg/kg copper increased egg production without having marked adverse effects, but 450 mg/kg copper altered some blood chemistry variables and reduced egg production in laying hens.  相似文献   

15.

Background

Permethrin is the active component of topical creams widely used to treat human scabies. Recent evidence has demonstrated that scabies mites are becoming increasingly tolerant to topical permethrin and oral ivermectin. An effective approach to manage pesticide resistance is the addition of synergists to counteract metabolic resistance. Synergists are also useful for laboratory investigation of resistance mechanisms through their ability to inhibit specific metabolic pathways.

Methodology/Principal Findings

To determine the role of metabolic degradation as a mechanism for acaricide resistance in scabies mites, PBO (piperonyl butoxide), DEF (S,S,S-tributyl phosphorotrithioate) and DEM (diethyl maleate) were first tested for synergistic activity with permethrin in a bioassay of mite killing. Then, to investigate the relative role of specific metabolic pathways inhibited by these synergists, enzyme assays were developed to measure esterase, glutathione S-transferase (GST) and cytochrome P450 monooxygenase (cytochrome P450) activity in mite extracts. A statistically significant difference in median survival time of permethrin-resistant Sarcoptes scabiei variety canis was noted when any of the three synergists were used in combination with permethrin compared to median survival time of mites exposed to permethrin alone (p<0.0001). Incubation of mite homogenates with DEF showed inhibition of esterase activity (37%); inhibition of GST activity (73%) with DEM and inhibition of cytochrome P450 monooxygenase activity (81%) with PBO. A 7-fold increase in esterase activity, a 4-fold increase in GST activity and a 2-fold increase in cytochrome P450 monooxygenase activity were observed in resistant mites compared to sensitive mites.

Conclusions

These findings indicate the potential utility of synergists in reversing resistance to pyrethroid-based acaricides and suggest a significant role of metabolic mechanisms in mediating pyrethroid resistance in scabies mites.  相似文献   

16.
Manual application of aqueous solutions of malathion, carbaryl and permethrin controlled northern fowl mite, Ornithonyssus sylviarum Canestrini and Fanzago, on caged layer hens for at least 118 days. Azamethiphos sprayed manually provided acceptable control for a shorter period. Machine application, particularly of azamethiphos, but also malathion, provided lesser control. The addition of surfactant increased the wetting ability of the sprays but interfered with the efficacy of azamethiphos.  相似文献   

17.
This study was conducted to evaluate the effect of early rearing conditions on physiological, haematological and immunological responses relevant to adaptation and long-term stress in white Leghorn hens with intact beaks housed in furnished cages (FC) or conventional cages (CC) during the laying period. Pullets were cage reared (CR) or litter floor reared (FR). From 16 to 76 weeks of age, hens were housed in FC (eight hens per cage) or in CC (three hens per cage). As measures of long-term stress at the end of the laying period, adrenal reactivity was quantified by assessing corticosterone responses to adrenocorticotropin challenge, and immune response was assessed by measuring antibody responses after immunization with sheep red blood cells (SRBC) and keyhole limpet haemocyanin (KLH). Heterophil to lymphocyte (H/L) ratio was employed as an indicator of stress. Rearing conditions significantly affected anti-SRBC titres (P < 0.0001) and tended to affect H/L ratios (P = 0.07), with the highest values found in FR hens. Layer housing affected H/L ratio (P < 0.01); the highest ratio was found in FR birds housed in FC during the laying period. This study shows that early rearing environment affects immunological indicators that are widely used to assess stress in laying hens. However, while results on H/L ratio indicated that FR birds experienced more stress particularly when they were housed in FC during the laying period, the immune responses to SRBC in FR hens was improved, indicating the opposite. This contradiction suggests that the effects on immune response may have been associated with pathogenic load due to environmental complexity in FR and FC hens rather than stress due to rearing system or housing system per se.  相似文献   

18.
Hypothalamic enzymatic luteinizing hormone-releasing hormone (LHRH)-degrading activity (LHRH-DA) may play a physiologic role in the neuroendocrine control of LHRH in mammals. The present study analyzes the existence and possible physiologic role of LHRH-DA in birds. The LHRH content in discrete hypothalamic samples of laying and nonlaying hens was correlated to their LHRH-DA. Degrading activity was assessed by high-performance liquid chromatography (HPLC) of chicken LHRH and of its degradation fragments. Luteinizing hormone-releasing hormone content was estimated by radioimmunoassay. Luteinizing hormone-releasing hormone content of discrete medial preoptic, infundibulum, and arcuate samples, as well as serum LH and progesterone levels, were higher (P less than 0.05) in laying than in nonlaying hens. The LHRH content of these hypothalamic areas was also higher (P less than 0.05) than those of immediately adjacent areas, in both animal groups. Luteinizing hormone-releasing hormone-degrading activity, which generates LHRH1-5 as the main degradation fragment, was higher (P less than 0.01) in the infundibulum of laying than in nonlaying hens. It was also higher (P less than 0.01) in samples from the infundibulum and medial preoptic area than in immediately adjacent lateral samples. Finally, LHRH-DA, showing a similar HPLC profile of degradation fragments, was also present in areas of low or undetectable LHRH content.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

19.

Backgound

Human scabies is a debilitating skin disease caused by the “itch mite” Sarcoptes scabiei. Ordinary scabies is commonly treated with topical creams such as permethrin, while crusted scabies is treated with topical creams in combination with oral ivermectin. Recent reports of acaricide tolerance in scabies endemic communities in Northern Australia have prompted efforts to better understand resistance mechanisms and to identify potential new acaricides. In this study, we screened three essential oils and four pure compounds based on eugenol for acaricidal properties.

Methodology/Principal Findings

Contact bioassays were performed using live permethrin-sensitive S. scabiei var suis mites harvested from pigs and permethrin-resistant S. scabiei var canis mites harvested from rabbits. Results of bioassays showed that clove oil was highly toxic against scabies mites. Nutmeg oil had moderate toxicity and ylang ylang oil was the least toxic. Eugenol, a major component of clove oil and its analogues –acetyleugenol and isoeugenol, demonstrated levels of toxicity comparable to benzyl benzoate, the positive control acaricide, killing mites within an hour of contact.

Conclusions

The acaricidal properties demonstrated by eugenol and its analogues show promise as leads for future development of alternative topical acaricides to treat scabies.  相似文献   

20.
In response to ethical concerns regarding the killing of day-old male chicks of layer breeds, the use of dual purpose chickens is increasingly discussed in public while data on nutritional requirements of dual purpose laying hens are not available. The present study examined the impact of an energy- and nutrient-reduced diet containing lignocellulose on performance, body composition and egg quality of dual purpose hens. Female Lohmann Dual chicks were allocated to 12 pens and fed two different diets for 52 weeks: a control (CON) and a treatment diet (LC), based on CON but diluted with 10% lignocellulose. During the trial, animal performance, whole-body composition and egg quality parameters of hens were consistently ascertained. The results showed that LC-fed hens had lower body weights compared to those receiving CON (p < 0.05). During the laying period, feed intake was increased in LC-fed hens (p < 0.001). LC-fed hens showed a higher egg production and egg mass resulting in an improved feed efficiency (p < 0.05) and laid smaller eggs compared to CON-fed hens (p < 0.001). At 52 weeks of age, bodies of LC-fed hens had higher protein and lower fat contents than those fed with CON diet (p ≤ 0.001). Mean body weight was positively correlated to the body fat content (p = 0.004) and body fat content was negatively correlated to the egg production (p = 0.043). Analyses of the egg quality showed that yolk mass at all sampling points and albumen mass at 27 and 42 weeks were lower in hens fed with diet LC compared to those fed with diet CON (p< 0.05). In conclusion, the feeding of energy- and nutrient-reduced diets containing 10% lignocellulose reduced the body fat content and simultaneously improved the laying performance in dual purpose hens.  相似文献   

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