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1.
1. Successful invasion by nematode parasites is associated with several factors including egg hatching at the right time in their hosts. To determine a simple and appropriate medium for culture and egg hatching of the highly pathogenic species of the Acuariidae family, Cheilospirura hamulosa were cultured in three different media. In addition the viability of C. hamulosa eggs was determined after storage in frozen infected gizzards.

2. Eggs removed from the uteri of the female worms in infected gizzards were pooled and washed in distilled water and screened under a stereo dissecting microscope. Eggs were counted and cultured in three different media, nutrient agar, normal saline 0.9% and Bearman, at room temperature. Additionally, 10 infected gizzards were kept at ?20°C for 2 and 8 months.

3. After 4–5 d there had been no growth in the nutrient agar medium, whereas 11% of the cultured eggs in the Bearman medium contained larvae 2–3 d after culturing. In 0.9% normal saline medium the two polar knobs appeared on the two poles of the eggs at 2 d post cultivation, and 74% of the eggs contained a larva on the third day. Mature larvae gradually exited from the eggs.

4. Eggs collected from female worms in gizzards frozen at ?20°C were cultured in the same three culture media at room temperature. Larvae were visible in the eggs after 2–3 d in the Bearman and 0.9% normal saline media and hatched thereafter.

5. The 0.9% normal saline medium is recommended for egg hatching and cultivation of C. hamulosa due for simplicity, efficacy and cost effectiveness. Moreover, freezing of the infected gizzards at ?20°C is proposed for long-term storage of the eggs.  相似文献   

2.
The direct exposure of fish eggs to ozonated water has generated interest as a means of ensuring pathogen-free eggs without the use of harsh chemicals. However, there are numerous knowledge gaps, including safe contact times, exposure levels, and potential long-term effects on aquaculture species in both freshwater and seawater. The effect of different ozone (O3) doses (0.5–1.0, 1.5–2.0, and 2.5–3.0 mg of O3/L for 90 s) on recently fertilized eggs of Atlantic Cod Gadus morhua and eyed eggs of Atlantic Salmon Salmo salar and Rainbow Trout Oncorhynchus mykiss was evaluated in comparison with the effects of two commercial disinfectants: Perosan (0.004 mg/L) and Ovadine (100 mg/L). The impact of ozone application was evaluated based on hatching success, larval nucleic acid concentration, larval growth, and survival. Overall, results indicated that ozonation of Atlantic Cod eggs at a dose less than 3.0 mg/L for 90 s produced no negative effect on the larvae up to 30 d posthatch. Furthermore, ozonation of Atlantic Salmon and Rainbow Trout eggs generated no negative effect on the larvae, based on monitoring until 85% yolk sac re-absorption (16 d posthatch).

Received May 6, 2014; accepted October 24, 2014  相似文献   


3.
Fish eggs, thought to be those of the liparid fish, Careproctus griseldea, were found In the gill chambers of several specimens of the stone crab, Lithodes tropicalls, caught In deep-water (-600 m) oil the South West African/Namibian coast (-24°46/S/13°28'E). The size class and quantity of crabs involved in this symbiotic relationship are discussed and some observations are made as to the diameter, number and maturity of the fish eggs removed from the crabs.  相似文献   

4.
Abstract

The risk of fish pathogen transmission via eggs can be reduced by disinfection in ozonated seawater. The aim of this study was to determine the suitable conditions for ozone disinfection of the eggs of gilthead seabream Sparus aurata, sea bass Dicentrarchus labrax, red porgy Pagrus pagrus, and common dentex Dentex dentex. The eggs were disinfected with a concentration (C) of 0.5 mg of ozone/L of water at four different exposure times (T = 2, 4, 8, and 16 min). The hatching rate was determined in triplicate for each treatment. Bacterial colonies were counted on tryptic soy agar and thiosulfate–citrate–bile salts–sucrose agar. At the end of the experiment, bacterial load and hatching rate were assessed together to determine the optimal ozone treatment values, which were estimated in CT units (i.e., C [= 0.5 mg/L] × T [min]). Optimal values were CT 2–4 (T = 4–8 min; 18°C) for gilthead seabream and red porgy, CT 2 (T = 4 min; 18°C) for common dentex, and CT 4 (T = 8 min; 15°C) for sea bass.

Received April 12, 2011; accepted February 2, 2012  相似文献   

5.
Felis catus, the domestic cat, is the definitive host for parasites that may result in adverse health outcomes in humans. Prevalence data of zoonotic parasites in feral cats, which are free‐roaming domestic cats that are born and live in the wild, are limited. The objective of this study was to assess seroprevalence of Toxoplasma gondii antibodies and copro‐prevalence of potentially zoonotic parasites in feral cats and to evaluate risk factors for seropositivity and faecal excretion of parasites. In this cross‐sectional survey, 275 feral cats at Trap‐Neuter‐Release clinics in Central Virginia were tested for parasites via faecal flotation, direct immunofluorescence assay (faeces) and modified agglutination testing (serum). Toxoplasma gondii seroprevalence was 22.35% (95% CI: 17.47–27.86). Faecal prevalence of T. gondii‐like oocysts was 1.04% (95% CI: 0.13–3.71), Toxocara cati 58.85% (95% CI: 51.54–65.89), Ancylostoma spp. 18.75% (95% CI: 13.49–25.00), Giardia duodenalis 5.73% (95% CI: 2.89–10.02) and Cryptosporidium spp. 3.33% (95% CI: 1.37–7.24). Female cats were more likely than males to excrete faecal Ancylostoma spp. eggs (OR 2.88; 95% CI 1.34–6.17). Adults were more likely than immature cats to be seropositive (OR 2.10; 95% CI: 1.11–3.97) and to excrete faecal Ancylostoma spp. eggs (OR 2.57; 95% CI: 1.10–5.99). However, immature cats were more likely than adults to excrete T. cati eggs (OR 6.79; 95% CI: 3.31–13.90) and to excrete one or more potentially zoonotic species (OR 4.67; 95% CI: 2.28–9.55) in faeces. Results of this study have implications for human and animal health and highlight the importance of collaboration between public health, medical and veterinary communities in preventive efforts.  相似文献   

6.
The serological response of 6 calves to experimental oral infection with between 60,000 and 100,000 Taenia saginata eggs at 3–12 months of age was monitored by the enzyme-linked immunosorbent assay (ELISA) and the tanned cell indirect haemagglutination technique (IDH). A serum antibody response was detected by both techniques by 2–3 weeks post infection, rising to a plateau about 4–6 weeks post infection. The serum antibody levels began to decline by about 30 weeks post infection. Two uninfected control cattle gave negative reactions.In addition, the serological response of 5 calves which had received a dose of 10,000 T. saginata eggs at 2–3 days of age and then weekly serial doses of 500 eggs for 12 months thereafter, was compared with a similar group of 5 calves, which had received the single infection of 10,000 eggs at 2–3 days of age only. Calves in both groups developed an antibody response detectable by the ELISA technique whereas those in a group of 5 control calves did not show such a response. When studied individually however there was marked variation in the serum antibody levels of these young cattle, as although some calves gave a relatively strong serological response, others hardly varied from the controls.  相似文献   

7.
The present article was conducted to evaluate the effect of in ovo injection of arginine on hatchability, immune system and caecum microflora of broiler chickens. For this reason, 300 fertile eggs were used in a completely randomized design with three experimental treatments. The experimental groups included: 1%–0.5% l -arginine (100 eggs), 2%–1% l -arginine (100 eggs), 3- control [included both sham control (injection of distilled water; 50 eggs) and control (no injection; 50 eggs)], which were injected on d 14 of incubation. After hatching, chicks of each experimental group (0.5% l -arginine, 1% l -arginine, and control groups) were randomly divided into four equal groups (as replicates) and reared for 30 days. Weight and feeding of chickens were recorded. Next, blood samples of chickens were collected on day 30 to evaluate antibody titre. Also, chickens were slaughtered on 24 and 30 days of the experiment to evaluate immune system organs and caecum microflora. Based on the results, in ovo injection of l -arginine had no significant effect on hatchability, body weight, antibody titre, spleen, bursa of Fabricius and thymus weight (p > .05). On the other hand, treatments significantly affected feed intake and feed conversion ratio (p < .05). As a novel finding, in ovo injection of l -arginine increased caecal Lactobacillus (p < .01), while decreasing Coliform and Escherichia Coli bacteria (p < .01). However, treatments did not influence caecal Enterococcus (p > .05). The overall results indicated that in ovo injection of 0.5% l -arginine had a better improving effect on caecal microflora and then considered as a recommended level of the present experiment.  相似文献   

8.
The egg and larval development of the Cape silverside, Atherina breviceps, are described and illustrated from material collected in the Swartvlei estuary. The eggs are spherical, 1,40-1,65 mm in diameter, with 6-12 uniformly spaced chorionic filaments attached at both ends to the chorion. TTie latter condition and the small size of the eggs are unique among the Atherina species. The larvae examined (5,1-15,7 mm) are elongate, have a yolk sac at hatching and are characterized by distinct body pigmentation and a prominent gas bladder. Flexion occurs between 7,6-11,2 mm, all fin elements are formed by 15,7 mm and scales develop by 20,0 mm. We compare the larval development of A breviceps with that of other atherinids and discuss the spawning of this species and the seasonal occurrence of larvae along the southern coast of Africa.  相似文献   

9.
Worldwide, foodborne illness is a significant public health issue in both developed and developing countries. Salmonellosis, campylobacteriosis and shigellosis are common foodborne gastrointestinal illnesses caused by the bacteria Salmonella spp., Campylobacter spp. and Shigella spp. respectively. These zoonotic diseases are frequently linked to eggs and poultry products. The aim of this study was to investigate the presence of these pathogens in Australian backyard poultry flocks and to determine risk factors for these pathogens. Poultry faeces samples were collected from 82 backyards and screened for Salmonella spp., Campylobacter spp. and Shigella spp. using qPCR. A questionnaire was administered to the backyard poultry owners to assess their knowledge regarding management of poultry and eggs and to identify potential risk factors that may contribute to the presence of zoonotic pathogens in the flocks. One composite faecal sample was collected from each backyard (82 samples). Composite sampling here means taking one or more grab samples from a backyard to make up approximately 10 grams. Four per cent of samples, that is 4% backyards tested, were positive for Salmonella spp., 10% were positive for Campylobacter spp. and none were positive for Shigella spp. A higher infection rate was seen in multi-aged flocks (24%) compared with the single-aged flocks (3%). The survey found that many participants were engaging in risky food safety behaviours with 46% of participants responding that they washed their eggs with running water or still water instead of wiping the dirt off with a damp cloth to clean the eggs and 19% stored their eggs at room temperature. This study demonstrated that backyard poultry may pose a potential risk for salmonellosis and campylobacteriosis. Additionally, Australian public health and food safety regulations should be modified and effectively implemented to address the risks associated with backyard poultry husbandry.  相似文献   

10.
Many egg-laying reptiles possess temperature-dependent sex determination (TSD) in which outcome of gonadogenesis is determined by incubation temperature during a temperature-sensitive period of development. Prior studies on Malayemys macrocephala showed that incubation temperatures influence gonadal development and suggested that M. macrocephala exhibits TSD. However, information on the temperature-sensitivity period in this species was unknown until the current study. Turtle eggs were collected from rice fields in central Thailand from December 2016 to February 2017. In the laboratory, eggs were incubated at male-biased temperature (26 °C) and shifted to female-biased temperature (32 °C), or vice versa. Single shift experiments were performed systematically during embryonic stages 13–21. After hatching, sex of individual turtles was determined by histological analysis. We found that the sex determination of M. macrocephala is affected by temperature up to stage 16 of embryonic development.  相似文献   

11.
Abstract

AIM: To describe the seasonal pattern of development of third-stage infective larvae (L3) from eggs of Teladorsagia (=Ostertagia) circumcincta, Trichostrongylus colubriformis and Haemonchus contortus on pasture in the North Island of New Zealand.

METHODS: Sheep faeces containing known numbers of eggs of all three nematode species were deposited on, or buried in, pasture plots at three sites, viz coastal Manawatu, Upper Hutt Valley, and East Cape hill country. Development was measured by recovering L3 from faeces, herbage and soil 28–31 days after deposition on 13–18 occasions, between January 2005 and July 2006. Analysis of the number of larvae recovered used a mixed model including number of eggs deposited, weight of faeces recovered (an assumed indicator of earthworm activity), site, contamination date, and position of deposited faeces, i.e. on the surface or buried.

RESULTS: There was a significant effect of contamination date on development of all three species, with maximum numbers ofL3 developing between late spring (November) and early autumn (March), and minimum numbers in June and July. There were large differences between species, with H. contortus exhibiting a long period (April to October) where development was close to zero, whereas T. circumcincta developed to some extent all year round. Development of T. colubriformis was intermediate between the other two species.

Burying faeces containing nematode eggs increased the number of L3 recovered compared with surface deposition (p≤0.001), although there were a small number of exceptions involving only T. colubriformis. The weight of faeces recovered at harvest, which was assumed to be an indication of earthworm activity, was correlated with the number of L3 recovered for all species (p<0.001). In a separate analysis, earthworms were assumed tohave been active if <5 g faeces remained at harvest. Where this occurred, the number of L3 of T. colubriformis and T.circumcincta recovered was reduced by 56% and 58%, respectively (p<0.001).

CONCLUSIONS: A marked seasonal pattern of development was observed for all three species, with the most larvae developing in spring-early autumn and the least in winter. This seasonal pattern was most pronounced in H. contortus and least obvious in T. circumcincta. Burying faeces containing eggs generally resulted in more L3 being recovered, whilst the apparent activity of earthworms resulted in fewer larvae being recovered.  相似文献   

12.
From data collected over the course of a year in a commercial broiler hatchery it was possible to infer the positions in the boxes that had been occupied during transit from farm to hatchery by 25,179 eggs subsequently downgraded upon candling. Two thousand seven hundred eggs were sampled from each of 168 consignments; the total number of eggs sampled was nearly half a million. They came from flocks of two strains and were candled by four candlers. Analysis of variance showed the downgrading rate to depend on (a) identity of the candler, (b) strain, (c) sample, which was confounded with flock and season, and (d) position of the egg in the box. Positional variation occurred in all three dimensions. Vertically (between trays) the downgrading showed a linear increase from top to bottom. Horizontally (within trays) the variation was such that eggs near the corners were at greatest risk, followed by those in the middle of the sides. Those in the centre of the tray were at least risk. The horizontal variation is believed to be due to damage caused by unidentified external objects (at the corners) and by the string with which the boxes were tied (at the middle of the sides). Within‐box variation accounted for the downgrading of 1 egg in 200. There is a need for further work on the design of egg trays and boxes.  相似文献   

13.
The redclaw crayfish Cherax quadricarinatus is a recent introduction into Lake Kariba, Zimbabwe where it is rapidly spreading. There are, however, no studies that have investigated the population dynamics and possible ecological impacts of the crayfish in the lake. This study investigated aspects of the population biology of C. quadricarinatus in the lake. These included sex distribution, population growth and mortality parameters, probability of capture, recruitment and length at age of ge at maturity. Crayfish were captured monthly between January and December 2013 from 13 sites using opera house bait traps. Aspects of the species population biology were estimated using a fish stock assessment tool, FISAT II. A total of 3 205 crayfish were captured, of which 44% were male, 49% female and 7% intersex individuals. The asymptotic length (L∞ = 112.88 mm), curvature parameter (k = 0.72), longevity (tmax = 4.17 years), growth performance index (? = 3.96), total mortality (Z = 2.06 y?1), fishing mortality (F = 1.07 y?1), natural mortality (M = 0.99 y?1), rate of exploitation (E = 0.52) and length-at-first capture (Lc = 44.48 mm) were estimated. Fecundity averaged 503 ± 229 eggs female?1 and increased with size (weight and carapace length). Gravid females were found throughout the year but the highest proportion of females with eggs (4–10%) were found in the first quarter, whereas recruitment peaked in May and June. The smallest crayfish with eggs (48.75 mm CL) was estimated to be 1.02 years and the largest (94.82 mm CL) 2.85 years. Cherax quadricarinatus exhibited an r strategy life-history pattern due to continuous reproduction and high fecundity. In Lake Kariba, C. quadricarinatus is now well into the establishment stage of the Introduction–naturalisation–invasion continuum and spreading in the lake. Management options should thus aim at preventing further spread and reducing the population size and the potential negative impacts of this species.  相似文献   

14.
Manfreda  G.  Cevoli  C.  Lucchi  A.  Pasquali  F.  Fabbri  A.  Franchini  A. 《Veterinary research communications》2010,34(1):179-182

Hot-air pasteurization was investigated in the EU-funded project “Reducing Egg Susceptibility to Contaminations in Avian Production in Europe (RESCAPE)” as an innovative treatment for surface bacterial decontamination of table eggs. Possible side effects of the treatment on egg quality traits were also studied. The decontamination power of hot air was evaluated over 1 month on shell eggs that were experimentally inoculated with Salmonella enteritidis, Escherichia coli, or Listeria monocytogenes. The S. Enteritidis and L. monocytogenes populations on the surfaces of treated eggs showed a significant reduction compared with untreated eggs. No statistically significant results were obtained comparing E. coli loads on treated and untreated eggs. No detrimental effects on quality traits either immediately after treatment or after 28 days of storage at 20°C were recorded.

  相似文献   

15.
《African Zoology》2013,48(2):197-204
For the period 1987 to 1998, pelagic eggs of marine fishes were collected from shelf waters at Park Rynie on the KwaZulu-Natal south coast. The three most numerous eggs collected were those of the mackerel Scomber japonicus,the sardine Sardinops sagax and the East coast roundherring Etrumeus teres. Together they comprised 67 % of all eggs collected. At times single-species egg densities were high, the highest accurately recorded was 850 eggs/cubic metre for S. sagax. All three species were predominantly winter to spring spawners. Theseasonal pattern of sardine eggs at Park Rynie suggests that after entering KwaZulu-Natal waters in June, sardines remain until November or December of each year before returning south to eastern Cape waters. Spawning in the East coast roundherring began in June, peaked in October to November, and tailed off in January. The mackerel showed a similar pattern of spawning, beginning in June and ending in December.  相似文献   

16.

  1. A total 120 laying hens (60 TETRA BLANCA white egg layers and 60 TETRA SL brown egg layers) were selected from 250 TETRA BLANCA and 250 TETRA SL pullets based on their predicted body fat content by means of computed tomography (CT) at 16 weeks of age. Three groups of pullets were chosen for the investigation with the highest (n = 20), lowest (n = 20) and average (n = 20) body fat content.

  2. Changes in the live weight, body fat content, egg production and egg composition of the chosen animals were recorded at 32, 52 and 72 weeks of age.

  3. Based on the results, it was established that differences in starting body fat content of the hens remained the same during the experimental period. The differences between the two extreme groups were statistically significant at each age.

  4. The starting body fat content of the hens affected the rate of egg production, i.e. hens with high starting body fat content produced 11–14 eggs fewer than the hens with a low or average body fat content but had no effect on the composition of the eggs.

  5. Genotype affected almost all of the examined traits: TETRA BLANCA hens had lower live weight and higher body fat content during the experimental period and produced fewer eggs with lower albumen and higher yolk, dry matter and crude fat content than the TETRA SL hens.

  相似文献   

17.
AIM: To investigate the anthelmintic properties of New Zealand native flax (Phormium tenax) for cattle, using a faecal egg count reduction test (FECRT).

METHODS: Twenty-six heifer calves with high (>300 epg) faecal nematode egg counts (FEC) were paired into two groups and fed either chopped flax leaves ad libitum, or barley straw at an equivalent dry matter (DM) rate, from Day 0–7; all were supplemented with 1.5 kg/head/day cereal feed supplement. On Days 8–10, all heifers were fed a common diet of 3.5 kg DM/ head/day barley straw and 1.5 kg/head/day cereal feed supplement. Heifers were weighed and faecal samples were collected on Days —6, 0, 7, and 10; samples were analysed in triplicate for FEC. The nutritive value of the flax and straw was analysed.

RESULTS: Both the flax and straw had low dry matter digestibility (DMD) and protein content. Although the flax-fed claves grew more than the controls, this may have been related to gut fill. Total daily faecal egg output was similar for flax and straw groups on Day 7 (14.7 vs 15.0 x 106 eggs/day, respectively) and Day 10 (14.9 vs 15.1 x 106 eggs/day, respectively). There was no difference in the change in FEC with time between the calves fed flax or straw diets.

CONCLUSION: Consumption of flax leaves did not reduce FEC in calves with a mixed nematode infection.  相似文献   

18.
1. Four experiments were carried out on eggs from broiler breeding flocks between 26 and 60 weeks of age. The effects of storage and incubation conditions on hatchability were tested.

2. Collecting eggs hourly rather than five hours after lay slightly reduced hatchability (P<0.10). Pre‐storage fumigation of almost un‐contaminated eggs had no effect on hatchability even after storage for 8 d. Storing eggs in unsealed polythene bags did not affect hatchability of eggs stored for 5 or 8 d.

3. Eggs stored for 2 d hatched better when held at 18 °C than at 15 °C (P<0.05). Eggs stored for 8 d at 15 °C hatched better than eggs stored for 8 d at 18 °C (P< 0.01). Best hatchability was in eggs stored in unsealed polythene bags at a room temperature of 15 °C. When older eggs were allowed 30 to 40 min more in the setter for each day of storage, the decline in hatchability was 0.5 to 0.6 percentage units per day in storage as compared with a decline of 1.2 percentage units per day when eggs of different storage times, up to 8 d, were set simultaneously.

4. Those eggs which showed a weight loss during incubation of near average for their relative humidity (RH) treatment tended to hatch better than others except under conditions of very low RH (0.36), when best hatchability was associated with lower than average weight loss.

5. In eggs from a young flock (28 to 44 weeks of age) hatchability of fertile eggs was depressed by 1 percentage unit with an increase in RH of 0.17, and by 1 percentage unit with each decrease of 0.06 in RH from a control RH of 0.53. In eggs from the same flock between 48 and 60 weeks of age hatchability was depressed by 1 percentage unit with each 0.037 increase in RH from 0.44 to 0.70.

6. Eggs from a young flock (34–49 weeks) hatched significantly better when maintained at 0.82 rather than at 0.66 (P<0.05) or 0.95 (P<0.10) RH during the hatching period from 19 to 21 d of incubation. Eggs from an older flock (51–61 weeks) hatched better at 0.82 and at 0.‐92 than at 0.72 RH during the same period, but the differences were not significant.  相似文献   


19.
Lambs from birth were reared in a tapeworm-free environment or on pasture contaminated with eggs of Taenia hydatigena. An examination for cysts at autopsy of some of the latter at 3 months of age revealed that they had ingested eggs. Eggs of T. hydatigena and T. ovis were fed at 6 months of age to lambs reared in the tapeworm-free environment and to some of those reared on the pasture. By comparing the number of cysts established at 9 months of age in the animals of each group, it was determined that those reared on the pasture had acquired some resistance to superinfection with T. hydatigena and infection with T. ovis. The remaining animals reared on the pasture were immunised (hyperimmunised) at 3 months of age by a parenteral injection of the eggs or embryos of T. hydatigena or T. ovis or both species. These animals were subsequently fed with the eggs of both species at 6 months of age. An examination of them for cysts at 9 months of age suggested that those immunisation procedures using the homologous organisms increased the resistance already acquired to superinfection with T. hydatigena and possibly also to that acquired to T. ovis. In addition, three of the procedures using homologous organisms appeared to induce regression of any cysts established from eggs of T. hydatigena ingested from the pasture prior to hyperimmunisation.  相似文献   

20.
本研究旨在了解褪黑激素受体基因MTNR1B的多态性及其与文昌鸡产蛋性状的关系。用直接测序的方法检测MTNR1B5′调控区、外显子1和外显子2的单核苷酸多态性,并将其与文昌鸡的产蛋性状进行关联分析。结果表明,在外显子1和2的编码区未发现碱基突变或缺失,而在5′调控区发现15个单核苷酸多态位点。其中-778位点突变(A→G)对文昌鸡中期(22～31周龄)产蛋数和46周龄总产蛋数的显性效应分别达到了2.3和6.2枚(P<0.05)。对后期(32～46周龄)产蛋数和46周龄总产蛋数而言,-216位点C对A为优势等位基因,加性效应值分别为2.5和3.2枚,显性效应分别为3.5和6.8枚,且表现为超显性。在4种单倍型中,AA单倍型个体的后期产蛋数和46周龄总产蛋数最低,GC单倍型个体的开产日龄最早。AC/GA联合基因型母鸡拥有最高的中期产蛋数、后期产蛋数和46周龄总产蛋数。综上所述,MTNR1B基因的外显子高度保守,而5′调控区的SNPs有望成为影响产蛋性状潜在的遗传标记。  相似文献   

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