Depletion of colistin in eggs following medication of laying hens

The depletion of colistin in eggs was determined separately for the albumen, the yolk and the whole egg after oral and intramuscular administrations of colistin sulphate. Residues were assayed by an agar plate diffusion method with Bordetella bronchoseptica ATCC 4617 as test organism. Colistin residues were not detected after drug administration by the oral route, but could be detected in the yolk until eight days after intramuscular injection. The total amount excreted represented 0.9% of the dose applied.     

Residues of macrolide antibiotics in eggs following medication of laying hens

1. The elimination kinetics of four macrolide antibiotics (tylosin, erythromycin, spiramycin and josamycin) in eggs were determined separately for albumen and yolk after oral administration through either drinking water or diet or after intramuscular injection. 2. Residues were assayed by a plate diffusion technique in cylinders with Micrococcus luteus as the test-organism. 3. Drug excretion was usually over a longer time in the yolk. Spiramycin was the most highly excreted in the egg whereas seven to eight times less tylosin and erythromycin was transferred. The conditions for the use of macrolide antibiotics in laying hens are discussed.     

Decreasing profile of residual sulphaquinoxaline in eggs

1. Sulphaquinoxaline (SQ) was added to the diet of laying hens at 200 mg/kg for 7 successive days. Contents (mg/kg) of SQ in albumen and egg yolk of eggs laid after drug withdrawal were determined by high pressure liquid chromatography (HPLC). The contents in the whole egg were calculated taking into consideration the respective weights of albumen and egg yolk. 2. A time-lag in the initiation of decrease of SQ from eggs after the withdrawal of dietary SQ was observed. 3. The decreasing pattern from whole egg could be well described by the following equation with a time-lag of 1.0 d, y = 2.07e-0.5620(t-1.0), where y is the SQ content in whole egg, t is time (d) after the withdrawal of dietary SQ and a constant of 2.07 is the SQ content in whole egg laid at the withdrawal. 4. Biological half-life of SQ in the whole egg was estimated to be 1.23 d. 5. From the above equation, SQ residue of whole egg laid at 9th d after withdrawal will be below the detection limit of 0.01 mg/kg.     

Teratogenicity testing of BI 58 EC (38% dimethoate) in chicken embryos with special respect to degradation of the active ingredient.

The insecticide formulation BI 58 EC was tested for teratogenicity in chicken embryos, with particular reference to degradation of the active ingredient (dimethoate) after the treatment of embryonated eggs. The pesticide was diluted in water to a concentration level of 0.8%, and the emulsion was injected into the air space in a volume of 0.1 ml/egg, or hen's eggs were treated by the immersion technique. Residues of dimethoate were measured in the samples on days, 13, 15 and 19 of the incubation of chicken embryos, and morphological examinations were performed simultaneously. Analytical chemistry data indicated a slower degradation of dimethoate in embryos after the immersion of eggs, and cyllosis was remarkable in this group among the sporadic developmental anomalies. The liver tissues of both treated groups exhibited severe fatty infiltration.     

Effect of a single injection of adrenaline on shell ultrastructure in a series of eggs from domestic hens

1. Adrenaline (1 mg in 1 ml water) was administered subcutaneously to three hens to determine whether any changes in the shell ultrastructure of subsequent eggs would occur. 2. The egg shells were examined in a scanning electron microscope after plasma etching. 3. The first three eggs laid by each bird after adrenaline injection were compared with previously-collected normal eggs from the same birds and also with control eggs collected over the same period from three hens which had received no adrenaline. 4. The first egg laid following adrenaline treatment was essentially normal but both the second and third eggs showed severe structural disorganisation at all levels, from the mamillary caps up to the cuticular layer. 5. Eggs laid 20 d or more after adrenaline treatment had reverted to normal. 6. The findings suggest that the abnormal eggs laid after hens have been exposed to disturbance or stress are likely to be affected in not only their external appearance but also to be of poor structural quality.     

Long-term egg production and heterosis in quail lines after within-line or reciprocal recurrent selection for high early egg production

1. Four Japanese quail lines were developed using 13 generations of reciprocal recurrent (lines AA and BB) or within-line selection (lines DD and EE) for high egg number until 98 d of age. In these lines and their reciprocal crosses, egg production, egg weight and mortality were monitored for up to 21 months to evaluate the impact of selection method and line origin on long-term production and heterosis. 2. Both hen-housed total egg number (EN) and hen-day egg laying rate (ELR) were consistently lower in recurrent lines than in lines under within-line selection: after 13 months of test, the difference was -47.1 eggs for EN and -20% for ELR%, whereas mortality was similar at around 20%. 3. Line EE was the best pure line for early egg production (55.2 eggs at 98 d of age) and also gave eggs which were consistently about 2 g larger than those from line DD but it had the highest overall mortality (78.5%) of all lines. On average, line DD laid 399 eggs (EN) over the whole experiment, 84 more than Line EE. 4. Crossbreds from the 2 types of pure lines and line DD had similar patterns and rates of egg production during the whole experiment, as indicated by the similarity of the curves adjusted for those lines by using the monomolecular model for EN and the modified compartmental model for ELR. 5. However, heterosis was higher from recurrent selection lines and it increased more with time than did heterosis from within-line selection lines.     

Salmonella enteritidis in chicken eggs

After an outbreak caused by salmonella enteritidis (SE) of which home-made mayonnaise and remoulade sauce were found to be the cause, SE was detected in ten of the remaining eggs. Subsequently 409 eggs of the next shipment from the same outlet were examined bacteriologically. Of 70 of the eggs examined, SE was found in 5 egg yolk samples and in 3 egg white samples as well as in 2 of 7 pooled shell samples. Five out of 35 pooled whole egg samples comprising a total of 349 eggs were likewise positive for SE. The isolates belonged to the phage types 4 and 7 carried the virulence plasmid pRQ29.     

A study to evaluate the field efficacy of ivermectin, fenbendazole and pyrantel pamoate, with preliminary observations on the efficacy of doramectin, as anthelmintics in horses

The efficacy of ivermectin, fenbendazole, pyrantel pamoate and doramectin was evaluated under field conditions at 2 sites in the Free State Province of South Africa. The study involved 25 horses at each site, divided into 5 groups of equal size. Ivermectin, fenbendazole and pyrantel pamoate were administered orally at doses of 0.2, 10 and 19 mg/kg respectively. Doramectin was administered by intramuscular injection at a dose of 0.2 mg/kg. Treatment efficacy was based on the mean faecal egg count reduction 14 days post treatment. At site A a faecal egg count reduction of 100% was found after treatment with ivermectin, fenbendazole and doramectin. A 96.1% reduction was found after treatment with pyrantel pamoate. At site B ivermectin and doramectin produced a 100% reduction in faecal egg counts, fenbendazole produced an 80.8% reduction and pyrantel pamoate a 94.1% reduction. Doramectin produced a 100% reduction in faecal egg counts at both sites, despite not being registered for use in horses. In addition, the results indicated reduced efficacy of fenbendazole at site B, which suggested benzimidazole resistance. Larval cultures showed that cyathostomes accounted for between 86 and 96% of pre-treatment parasite burdens at both sites. Other helminths identified in the faecal samples were Strongylus spp. and Trichostrongylus axei.     

Control of cyathostome infections in mares treated at parturition with ivermectin

Six mares were treated on the day of parturition with an intramuscular injection of 0.2 mg kg-1 ivermectin and placed in a pasture free of equine parasites as soon as possible after foaling. The mares and their foals were compared with a similar group of untreated mares and foals on an adjoining pasture. The experimental data was derived from mare and foal fecal egg counts, foal necropsies and pasture larval counts. Ivermectin administered to mares on the day of parturition, when combined with movement to parasite-free pastures, significantly lowered the cyathostome (small strongyle) egg production for 4 months. This reduced cyathostome exposure was reflected in lower worm-burdens in their foals for 5 months. The results indicate that ivermectin will effectively control equine strongyles when mares and their foals are moved to parasite-free pastures.     

Lithium induction of premature ovi‐position by the Japanese quail 1

1. The intramuscular injection of LiCl into laying Japanese quail 6 or 12 h subsequent to an oviposition induced early oviposition of the next egg.

2. The shells of eggs from Li‐treated birds were without speckling and weighed half or less as much as shells from Na‐treated birds. Many eggs were also deficient in albumen.     

Evidence of Ivermectin Resistance by Parascaris equorum on a Texas Horse Farm

By collecting fecal samples every 2 weeks beginning at 2 months of age, 32 foals from a single Texas farm were monitored. The foals were administered ivermectin paste at the time of the first collection and again monthly. When foals had Parascaris egg counts higher 2 weeks after ivermectin treatment than at treatment, they were administered pyrantel pamoate at the manufacturer's recommended dose (6.6 mg/kg) or at twice the recommended dose (13.2 mg/ kg) when tapeworm eggs were also detected. An elevation or only minimal reduction (less than 75%) in Parascaris egg counts was seen 2 weeks after ivermectin treatment until the foals were 8 months of age, at which time there was an 85% reduction in fecal egg count after treatment. When pyrantel was administered at the manufacturer's recommended dose, a 42% to 84% reduction in egg counts occurred, but at 13.2 mg/kg there was a 98% to 100% reduction in fecal egg counts 2 weeks posttreatment. However, pyrantel failed to control strongylate egg counts even at the elevated dose, whereas ivermectin reduced strongylate fecal egg counts by greater than 99%, determined 2 weeks posttreatment. Pyrantel, but not ivermectin, lowered Parascaris egg counts. Ivermectin, but not pyrantel, lowered strongyle egg counts 2 weeks post administration. A single drug for all ages of horses approach to parasite control requires rethinking. Combinations of drugs or more careful evaluation of anthelmintics in foals may be necessary for continued parasite control.     

Residue depletion of ampicillin in eggs

A residue depletion study of ampicillin (AMP) was performed after oral dosing (60.0 mg/kg and 120.0 mg/kg body weight once a day for 5 days) to laying hens, through the use of reversed‐phase high‐performance liquid chromatography with fluorescence detection (RP‐HPLC‐FLD) to achieve detection of ampicillin residue in eggs. Limit of detection was 0.5 ng/g, and limit of quantitation was 1.2 ng/g for ampicillin. Extraction recoveries of ampicillin from samples fortified at 5.0–125.0 ng/g levels ranged from 77.5% to 84.6% in albumen, 77.9% to 87.5% in yolk, and 77.9% to 88.6% in whole egg, with coefficients of variation ≤9.3%. The maximum concentrations of ampicillin in albumen, yolk, and whole egg were detected at 1, 2, and 1 day after the last administration of ampicillin, respectively. Ampicillin was not detectable in albumen at day 9 of withdrawal time, at day 10 and 11 in yolk, and day 9 and 11 in whole egg at each of those 2 dose levels. The theoretical withdrawal time of AMP in whole egg was 6.730 and 7.296 days for 60 and 120 mg/kg oral dosage, respectively. This method also proved to be suitable as a rapid and reliable method for the determination of ampicillin in other poultry eggs.     

Residues of sulphadimidine and its metabolites in eggs following oral sulphadimidine medication of hens

The depletion of sulphadimidine (SDM) and its N4-acetyl and hydroxy metabolites was studied in eggs laid by hens after administration of either a single or multiple oral dosages of 100 mg SDM/kg. During medication and until 1 day after the last dose, the SDM and its metabolite concentrations in the egg white exceeded those in the egg yolk and reflected the plasma levels. In the period starting 2 days after the (last) dosage, the SDM concentration in the yolk became higher than in the egg white, and the drug depletion curves ran parallel. The mean maximum amount of SDM found in the whole egg was 1500 micrograms after a single and 1280 micrograms after multiple dosage. In eggs, traces of the N4-acetyl and 6-methylhydroxy metabolites could be detected (mainly in the egg white), and their concentrations were approximately 40 times lower than those of the parent drug. A highly significant correlation (P less than 0.005) was found between the development stage of the oocyte at the time of (last) medication and the amount of SDM found in the egg that developed from it. A period of 7 or 8 days after the (last) dosage of 100 mg SDM/kg/day is required to obtain SDM levels below 0.1 micrograms/g egg.     

Efficacy of Ivermectin Pour-on Against Nematodes Infecting Foals on Pasture: Coprological and Biochemical Analysis

The efficacy of topical ivermectin (IVM) on foals naturally infected by parasitic nematodes was evaluated. Two dosages of IVM were applied pour-on (F-Nor0.5; 0.5 mg/kg body weight [BW] and F-Nor1; 1 mg/kg BW) and results compared with the oral administration (F-Eq0.2; 0.2 mg/kg BW of IVM). The efficacy was measured by estimating the reduction in the fecal egg counts (fecal egg count reduction) and in the numbers of horses shedding parasite eggs (positive horse reduction). Several biochemical and enzymatic serum parameters were measured in the groups F-Eq0.2 and F-Nor1. Before the deworming of the horses, eggs of Parascaris equorum, Cyathostomum, Gyalocephalus spp, and Oxyuris equi were identified. In all the treated groups, the excretion of ascarid eggs ended 4 days after the treatment. The orally administered IVM suppressed the egg output of strongyles and pinworms 4 days after the treatment, whereas for the F-Nor1 group this occurred 8 days after the treatment. Eggs of strongyles were detected in the F-Nor0.5 group throughout the study. The levels of blood urea nitrogen, creatinine, total proteins, albumin, globulins, and lactate dehydrogenase (LDH) reduced significantly after the administration of IVM, but values not within the normal range were only achieved for LDH. A significant positive correlation between the fecal egg output of cyathostomins and the LDH was investigated. Clinically, no adverse reactions in the horses receiving the topical IVM were observed. It was concluded that the pour-on administration of 1 mg/kg BW IVM provides similar results to the oral administration, and offers a very useful tool to control infestation by the intestinal nematodes affecting wild grazing horses.     

Nutritive constituents of Silky fowl eggs: comparison with hen eggs of White Leghorn origin

In the present study, proportional parts, amounts of major constituents, vitamins, minerals and fatty acids composition of Silky fowl eggs were examined compared with those of hen eggs. The ratio of egg yolk weight to whole egg weight of Silky fowl egg was significantly larger than that of egg yolk of hen egg. The amount of cholesterol of Silky fowl eggs were significantly (P < 0.01) less than those of hen eggs. The amount of vitamins (B2, B6, D and E), calcium and potassium in Silky fowl eggs were significantly higher than those of hen eggs. Unsaturated fatty acids in Silky fowl eggs were 62.5% among total fatty acids, the unsaturated fatty acids of hen eggs were 53.9%. Especially, the contents of arachidonic acid, docosapentaenoic acid and docosahexaenoic acid in Silky fowl eggs were significantly larger than in hen eggs.     

Identification of foals infected with Parascaris equorum apparently resistant to ivermectin

During September 2002, routine fecal examinations performed on 16 Thoroughbred foals residing on a farm outside Toronto, Ontario, Canada, revealed low to moderate numbers of Parascaris equorum eggs in feces from 9 of the 16. All foals were then treated with ivermectin at a dose of 220 to 280 microg/kg (100 to 127 microg/lb), p.o., and fecal egg counts were repeated 12 days later. Fecal P. equorum egg counts increased between the first and second fecal examination in 7 foals, were unchanged in 1, and decreased in 5. Fecal samples were collected 13 days after treatment from 21 additional foals that had been treated with ivermectin at the same dose, and P. equorum eggs were detected in 12 of the 21. For all 37 foals, high P. equorum egg counts (> or = 100 eggs/g of feces) 12 to 13 days after ivermectin treatment were significantly more likely in foals that had been regularly treated with ivermectin since birth and permanently resided on the farm, compared with foals that had been treated with other anthelmintics or had an unknown deworming history. Collectively, these data suggested that P. equorum in these foals was resistant to ivermectin administered at the recommended dose.     

Detection of antibodies to Hypoderma lineatum in cattle by Western blotting with recombinant hypodermin C antigen

A study was conducted to evaluate the therapeutic efficacy of doramectin administered intramuscularly at a dose rate of 200 microg/kg to sheep harbouring naturally acquired infections of gastrointestinal nematodes and Oestrus ovis in the southwestern region of France. On day 0, 24 sheep were selected on the basis of positive faecal egg counts (>100 EPG) and positive assessment of O. ovis infection (including positive O. ovis antibody level and positive clinical score). The sheep were randomly allocated to a non-medicated control group (T1) or a doramectin-treated group (T2) of 12 animals each. On day 0, sheep in group T2 received a single intramuscular injection of doramectin (200 microg/kg), whereas those in group T1 received an intramuscular injection of saline solution (sodium chloride, 0.02ml/kg). Individual faecal egg counts were performed on days 0, 1, 2, 3, 4, 5, 6, 7, and 14. Between days 14 and 16, all sheep were slaughtered, and worm and O. ovis burdens were determined. In doramectin-treated sheep, faecal egg counts had decreased to zero by day 4 for all recovered types of nematode eggs: strongyles, Nematodirus sp., Trichuris sp., and Rhabditidae sp. For strongyles, Nematodirus sp., and Rhabditidae, the percentage reductions in faecal egg counts (geometric means) of doramectin-treated sheep, compared to the non-medicated control sheep were 100% from days 4-7. For Trichuris sp., they were 100, 99.7, 99.9, and 100% on days 4, 5, 6, and 7, respectively. On day 14, percentage reductions were 100% for Nematodirus sp. and Rhabditidae, and 99.8 and 99.1% for strongyles and Trichuris sp., respectively. At necropsy, only adult nematodes and mainly first-stage O. ovis larvae were recovered. Doramectin was highly efficacious against the adult stages of Teladorsagia circumcincta (100%), Nematodirus battus (100%), Nematodirus filicollis (99.9%), Oesophagostomum venulosum (99.8%), and Trichuris sp. (99.3%). It was also 100% efficacious against first-stage larvae of O. ovis. No abnormal clinical signs or adverse reactions in any of the sheep treated with doramectin were observed.     

Presence and recovery of Ascaridia dissimilis ova on the external shell surface of turkey eggs.

Ascaridia dissimilis, a roundworm in turkeys, has been noted with increased frequency in commercial turkeys. Because infected turkeys can shed A. dissimilis ova in their feces, the potential exists for the external surface of turkey eggshells to be contaminated with A. dissimilis ova. The objectives of this study were to determine the presence of and recover A. dissimilis ova on the external surface of the turkey egg. In Experiment 1, turkey eggs were collected from naturally infected flocks, and eggs were processed by a sodium hydroxide procedure to recover any A. dissimilis ova on the external egg surface. In Experiment 2, the external surface of the turkey eggs was inoculated with 116 A. dissimilis ova/g feces, and eggshells were sampled every 3 days until 28 days of incubation to assess the recovery of A. dissimilis ova from the eggshell. In Experiment 1, of the 36 eggs examined from a flock naturally infected with A. dissimilis, one egg had an A. dissimilis ovum on its external eggshell surface. Experiment 2 demonstrated that A. dissimilis ova can be recovered from the external egg surface after a 28-day incubation period in the incubator. Ova recovery declined from an average of 62 A. dissimilis ova/turkey egg at day 2 of incubation to an average of 3 A. dissimilis ova/turkey egg at day 28 of incubation.     

Examination of egg number and egg weight variables and their effects on daily management in aviary systems for laying hens

1. Characteristics of egg numbers and mean egg weight were examined for their usefulness in the daily management of aviary systems for laying hens.

2. A number of 3238 brown Isabrown/Warren hens were housed in 1 compartment, a separated part of the house where the hens could move around freely, of a tiered‐wired‐floor aviary system (TWF‐system). An automatic egg weighing and counting system (EWACS) was used to count and weigh eggs daily from 2 tiers of laying nests on 1 side of the compartment and the number of eggs for the whole compartment were counted daily by the farmer. Each tier was divided into 16 blocks of 5 individual laying nests. Two adjoining blocks were called a group. To prevent hens from walking along all the laying nests in a tier, partitions were placed on the perches in front of the laying nests, between nest groups 2–3, 4–5, and 6–7.

3. After the first 3 weeks of the laying period, the distribution of egg numbers over the nest groups within a tier became stable. If egg numbers were counted daily from only 1 nest group the coefficient of variation was 23.1%. If the eggs from the whole compartment were counted daily, the coefficient of variation for the number of eggs was 2.8%. The nest group, presence of a partition and tier level influenced the daily number of eggs.

4. The distribution of the mean egg weight over the different nest groups within a tier was stable for the whole laying period. The coefficient of variation of the daily mean egg weight for a nest group was 3.1%. The difference in mean egg weight between nest groups was small, between 0.1 and 0.6 g, and the level of tiers and the presence of partitions between nest groups had no effect on the mean egg weight.

5. It could be concluded that egg numbers could not be estimated reliably by taking samples from a group of laying nests or a tier, but that it was necessary to count all the eggs from a compartment. The daily mean egg weight, however, could be estimated reliably on the basis of a sample of eggs from a nest group or a tier. By using EWACS frequent samples could be taken, which diminished the coefficient of variation so that the reliability of the data increased.