Effect of prolonged heat stress in single-comb white leghorn hens on progeny resistance to Salmonella enteritidis organ invasion.

In our laboratory, we have often had difficulty infecting neonatal chickens with invasive salmonellae when ambient temperatures exceed 30 C. We hypothesized that this increased resistance in chicks during warmer months may be associated with heat stress-associated maternal factors. Presently, single-comb white leghorn hens were separated into a non-heat-stressed group, reared under temperatures from approximately 10 to 24 C, and a heat-stressed group, in which environmental temperature was incrementally elevated to near 37 C and maintained for the duration of the 13-wk study. For Expt. 1, eggs from heat-stressed or control hens, collected on days 8-14 of the study, were pooled respective to treatment and incubated. At the time of egg collection, mean hen-day egg production was 51.83% or 65% for heat-stressed or control hens, respectively. On day of hatch, progeny from hens in each group were orally challenged with 0.9 x 10(4) colony-forming units (CFU) Salmonella enteritidis (SE). Rates of SE organ invasion of 97.3% or 94.4% were obtained in progeny from heat-stressed or control hens, respectively. In Expt. 2, eggs from heat-stressed or control hens from days 30-42 of the study were collected and pooled by treatment for incubation. Mean hen-day egg production was 46.5% or 72.85% for heat-stressed or control hens, respectively. On day of hatch, progeny were orally challenged with either 2.2 x 10(3) or 2.2 x 10(4) CFU SE. A 100% incidence in SE organ invasion was observed in all groups. In Expt. 3, eggs were collected from days 43 through 56 of the study. Mean hen-day egg production was 19.8% or 76.8% for heat-stressed or control hens, respectively. On day of hatch, progeny were orally challenged with 2 x 10(3) CFU SE. Rates of SE organ invasion of 95.8% or 95.6% were obtained in progeny from heat-stressed or control hens, respectively. These data suggest that factors other than elevated temperature may be responsible for seasonal resistance to invasive salmonellae infection in neonatal chickens observed in our laboratory during warmer months in Texas.     

The epidemiology of nematode and fluke infections in cattle in the Red River Delta in Vietnam

Over a period of 13 months, faecal samples were collected monthly from approximately 45 cattle over 3 months of age. Additionally, 74 calves of 1-2 months were sampled to determine the presence of Toxocara vitulorum eggs. Individual egg counts and infective strongyle larvae from pooled faecal samples were examined. Post-mortem worm counts were carried out on six groups of tracer calves (n=12) that had been kept for 4 weeks on pasture in and around the village studied. The following helminths were identified: T. vitulorum, Cooperia punctata, C. pectinata, C. oncophora, Oesophagostomum radiatum, Trichostrongylus axei, T. colubriformis, Haemonchus spp., Fasciola spp. and Paramphistomum spp. In 8% of the samples collected from young calves, individual egg counts for T. vitulorum were found indicative for pathogenic worm burdens. Strongyle egg counts and worm counts indicated that transmission is low without a distinct seasonality. In animals of 3-9 months old, a strongyle egg count peak can be demonstrated which at a higher age steadily and significantly decreased. In faecal cultures Cooperia spp. were most prominent in all age groups throughout the year with the exception of the period September-November when Haemonchus spp. and Oesophagostomum spp. were most prevalent. Fasciola spp. eggs were found in 22% of the collected faecal samples and the egg counts were low indicating that the intensity of Fasciola spp. infection is mild. Based on the present data, regular anthelmintic treatments seem not to be justified, except for a single treatment at the age of 2 weeks against toxocariosis.     

The use of age-clustered pooled faecal samples for monitoring worm control in horses

A study was performed on two horse farms to evaluate the use of age-clustered pooled faecal samples for monitoring worm control in horses. In total 109 horses, 57 on farm A and 52 on farm B, were monitored at weekly intervals between 6 and 14 weeks after ivermectin treatment. This was performed through pooled faecal samples of pools of up to 10 horses of the groups 'yearlings' (both farms), '2-year-old' (two pools in farm A), '3-year-old' (farm A) and adult horses (four pools on farm A and five pools on farm B), which were compared with the mean individual faecal egg counts of the same pools. A very high correlation between the faecal egg counts in pooled samples and the mean faecal egg counts was seen and also between the faecal egg counts in pooled samples and larval counts from pooled faecal larval cultures. Faecal egg counts increased more rapidly in yearlings and 2-year-old horses than in older horses. This implied that in these groups of young animals faecal egg counts of more than 200 EPG were reached at or just after the egg reappearance period (ERP) of 8 weeks that is usually indicated for ivermectin. This probably means that, certainly under intensive conditions, repeated treatment at this ERP is warranted in these young animals, with or without monitoring through faecal examination. A different situation is seen in adult animals. Based on the mean faecal egg counts on both farms and on the results of pooled samples in farm A, using 100 EPG as threshold, no justification for treatment was seen throughout the experimental period. However, on farm B values of 100 EPG were seen at 9 and 11, 13 and 14 and 14 weeks after ivermectin treatment in pools 10, 12 and 13, respectively. This coincided with the presence of one or two horses with egg counts above 200 EPG. The conclusion is that random pooled faecal samples of 10 adult horses from a larger herd, starting at the ERP and repeating it at, for instance, 4-week intervals, could be used for decisions on worm control. However, there would be a certain risk for underestimating pasture contamination through missing high-egg excreters. An alternative use of pooled samples would be as a cheap first screening to detect which adult horses really contribute to pasture contamination with worm eggs on a farm. All horses should be sampled and subsequently animals from 'positive' pools can be reexamined individually.     

Isolation of infectious bronchitis virus from intestine and reproductive organs of laying hens with dropped egg production

A total of 52 samples (22 cloacal swabs and 30 pooled ovaries and oviducts) from hens with a history of a 25 to 40% drop in egg production from 30 flocks were examined for the isolation of infectious bronchitis virus in embryonated chicken eggs. Five isolates were obtained: three from cloacal swabs and two from reproductive organs. These isolates were identified and characterized on the basis of agar-gel-precipitation, hemagglutination, and neutralization tests and other physicochemical characteristics.     

Evaluation of the efficacy of Salmonella enteritidis oil-emulsion bacterin in an intravaginal challenge model in hens.

The efficacy of Salmonella enteritidis (SE) oil-emulsion bacterin (a commercially available vaccine) was evaluated in an intravaginal challenge model in hens producing a high rate of SE-contaminated eggs. Hens were vaccinated at 38 wk of age. A second (booster) bacterin injection was administered 4 wk later. Two weeks after the second vaccination, all hens were challenged intravaginally with 10(7) colony-forming units of SE. After challenge, 36 of 189 eggs (19.0%) in the vaccinated hens were positive for SE, and this contamination rate was significantly (P < 0.01) lower than that in the unvaccinated hens (61 of 165 eggs, 37.0%). SE was highly recovered from the cloacal and vaginal swabs of the unvaccinated and vaccinated hens, but the number of SE from the cloaca of the vaccinated hens was significantly (P < 0.05) lower than that in the unvaccinated hens at 7 days post-challenge (PC). The recoveries of SE from the spleen and ovary in the vaccinated hens were significantly (P < 0.05) lower than those in the unvaccinated hens at 7 days PC. At necropsy, SE was recovered from 2 of 15 forming eggs (13.3%) taken from the oviducts of the unvaccinated hens, whereas no SE was recovered from 17 forming eggs in the vaccinated hens. After vaccination, serum antibodies for SE in the vaccinated hens were significantly higher than those in the unvaccinated hens. Antibodies from the oviductal washing, especially immunoglobulin G isotype, in the vaccinated hens were higher than those in the unvaccinated hens after challenge. This intravaginal challenge model produced frequent contaminated eggs and clearly demonstrated the ability of the bacterin to protect against egg contamination. The present model may be a useful tool for further studies to evaluate the protective effect against SE contamination of eggs by potential vaccine candidates.     

A case study on Salmonella enteritidis (SE) origin at three egg-laying farms and its control with an S. enteritidis bacterin

In the early 1990s, three egg-laying farms (farms S, T, and B) were thought to have the possibility of Salmonella enteritidis (SE) contamination because positive liquid egg samples originated from those farms. The present study was therefore conducted. The first clarification for SE contamination was the study on the origin of SE contamination including its vertical transmission. The results of SE contamination profiling with dust and manure, food materials, dead embryos, and residual yolks on hatch day in regular monitoring over a few years were clearly negative. Therefore, we concluded the SE transmission/infection was attributed to horizontal infection in the egg-laying farms but not vertical transmission from parental stock, hatcheries, growth, or food materials during a 7-yr experimental period. Second, we attempted to clarify if administration of an SE bacterin (Layermune SE) to growth flocks for the egg-laying farms could reduce SE incidence in liquid egg samples from each egg-laying farm. In the first experiment, we compared SE incidence in liquid egg samples from vaccinated and nonvaccinated flocks (similar age flocks). SE incidence from vaccinated and nonvaccinated flocks showed negative and <2 most probable number (MPN)/100 ml for farm B, <2 and >1600 MPN/100 ml for farm S, and negative and >1600 MPN/100 ml for farm T, respectively. In the second experiment, we compared the SE isolation incidence in the liquid egg samples from nonvaccinated and newly replaced vaccinated flocks in the same chicken houses from each of the three egg-laying farms. SE incidence in the liquid egg samples was similar to that in the first experiment. Therefore, the SE bacterin may play an important role in reducing the SE incidence of liquid egg samples.     

Growth of Salmonella typhimurium and Salmonella enteritidis in egg yolks from highly immunized hens.

This experiment was conducted to ascertain whether the growth of Salmonella Enteritidis (SE) or Salmonella Typhimurium (ST) would be suppressed in the presence of antibodies contained in egg yolks. Specific pathogen-free chickens (102 days of age) were subcutaneously immunized with oil-adjuvanted bacterin of SE or ST, twice within a four-week interval. During 160 to 170 days of age, eggs were collected, the yolks were removed and mixed with an equal volume of physiological buffered saline, inoculated with ten colony forming units (CFU) of SE or ST, and incubated at 37 degrees C or 20 degrees C for 23 hr. The growth of organisms in each yolk solution was examined. The egg yolk derived from non-immunized hens was examined in the same manner as the controls. There was no difference in the growth titer between the antibody-positive yolk and the negative yolk. The result suggests that the antibodies in the yolk do not influence the growth of each organism, even if the hens are highly immunized.     

The influences of SE infection on layers’ production performance,egg quality and blood biochemical indicators

Background： Salmonella enterica serovar Enteritidis （SE）, as a major cause of foodborn illness, infects humans mainly through the egg. However, the symptom of laying hens usually is not typical and hard to diagnosis. In the present study, it is studied that the influences of SE infection on layers＇ performance, egg quality and blood biochemical indicators. It will help us to improve the strategy to control SE infection in commercial layers. One hundred layers at 20 wk of age were divided into 2 groups, 60 hens for experiment and others for control. The experiment group was fed with the dosage of 108 CFU SE per hen. The specific PCR was used to detect the deposition of SE. On the 8 d after SE infection, 10 hens from the control group and 30 hens from the experimenta group were slaughtered to detect the SE colonization. The production performance, egg quality and blood biochemical indices were also analyzed. Results： The results showed that the colonization rate of SE was highest in caecum contents （55.17%） and lowest in vagina （17.24%）. For the eggs the detection rate of SE was highest on the eggshell （80.00%） and lowest in yolk （18.81%）. SE infection had no significant influence on production performance and egg qualities （P 〉 0.05）. The difference of laying rate between the experimental and control groups was less than 0.30%, and both were approximately equal to 82.00%. The blood analysis showed that the aspartic aminotransferase （AST） and alanine aminotransferase （ALT） of experimental group was significantly higher than those of control group （P 〈 0.05）. For experimental and control groups AST values were 236.22 U/I and 211.84 U/I respectively, and ALT values were 32.19 U/I and 24.55 U/I. All of coefficients were less than 20%. The colonization of SE in organs increases the enzyme activities of AST and ALT in blood. Conclusions： SE in feed could invade the oviduct and infect the forming eggs. It significantly increased the concentration of ALT and AST in blood. Ho     

Freezing of sheep faeces invalidates Haemonchus contortus faecal egg counts by the McMaster technique

Faecal pellets from a sheep that was artificially infected with a monoculture of Haemonchus contortus were collected over a 2-h period in the morning. In the laboratory the faeces were thoroughly mixed by hand and 48 by 1 g aliquots of the pellets were sealed in plastic bags, from which the air had gently been expressed. The faecal worm egg count of the sheep was about 14,000 g(-1). Varying numbers of the bags were either processed for faecal worm egg counting (FEC) by the McMaster technique on day 0, or were stored at one of the following temperatures: about 4 degrees C, -10 degrees C or -170 degrees C before processing. The faecal aliquots that were frozen were thawed at room temperature after having been frozen for either 2 h or 7 days, and processing of aliquots maintained at 4 degrees C proceeded shortly after the samples had been removed from the refrigerator. A dramatic reduction in egg numbers was found in all the aliquots that were frozen at -170 degrees C before faecal worm egg counts were done, as well as in those frozen for 7 days at about -10 degrees C. Numerous empty, or partially empty, egg shells were observed when performing the counts in faeces that had been frozen. In contrast, there was no significant reduction in the numbers of eggs in aliquots maintained for 7 days in a refrigerator at +/- 4 degrees C before examination, when compared with others examined shortly after collection of the faeces. Since H. contortus eggs in faeces are damaged by freezing, some methods that can be used for short term preservation are outlined. It is concluded that all nematode egg counts from cryopreserved faeces (whether in a freezer at -10 degrees C or in liquid nitrogen) should possibly be regarded as being inaccurate, unless the contrary can be demonstrated for different worm genera. However, exceptions are expected for the more rugged ova, such as those of the ascarids and Trichuris spp.     

Evidence for the vertical transmission of Sunshine virus

Sunshine virus is a paramyxovirus of pythons associated with neurorespiratory disease and mortalities. This report provides evidence for its vertical transmission. In a collection of over 200 Australian pythons, a dam and a sire, both carpet pythons (Morelia spilota), were PCR-positive for Sunshine virus at a time when the dam was likely to have been gravid. A clutch of 21 eggs was laid and three non-viable eggs were tested for the presence of Sunshine virus by PCR. One egg had been incubating for 34 days while the other two had been incubating for 49 days. The surface of all three eggs was negative for Sunshine virus but swabs of the allantois and amnion were positive in all three eggs. Embryo tissue samples were tested from the two 49 day old eggs. From one embryo, a sample of brain and a pooled sample of lung, liver, kidney and intestine were positive, while for the other embryo, a pooled sample of lung, liver, kidney, intestine and brain was positive. Fourteen of the 21 eggs hatched and all hatchlings were tested by PCR at least once between the ages of 53 and 229 days old. All hatchlings were PCR-negative for Sunshine virus.     

Effects of coated hatching eggs obtained from old broiler breeders with chitosan on embryonic growth,hatching results and chick quality

The aim of this research was to determine the effects of coating broiler hatching eggs with chitosan on egg quality, embryonic growth, hatching results and chick quality. Eggs obtained from old broiler breeder, aged 59 weeks, were used. Eggs were divided into two groups (coated with chitosan and uncoated) groups. Each group was divided into three groups according to the storage period. Eggs were stored for periods of 1, 4 and 7 days at 15°C and 80% humidity. Then, they were incubated. Storage period of eggs up to 7 days did not affect the egg quality, egg weight loss, embryo growth, chick properties and hatchability of fertile eggs. However, embryo development, relative residual yolk sac weight and relative chick weight were affected by coating eggs with chitosan. Interaction was not found between storage lengths and coating of eggs with chitosan for all examined parameters. The results of the present study suggested that hatching eggs obtained from old broiler breeder flocks were immersed into chitosan solution once and quickly have negative effect on the embryo weight, yolk sac absorption and relative chick weight. It has been observed that covering the hatching eggs with chitosan is not suitable in this respect even if immersion takes place once and in a short time.     

Tetrameres americana Cram (1927) populations in chickens infected with different dose levels

Three groups of 20-45 Lohman brown chickens aged 3 weeks were orally infected with doses of 25, 100 and 400 Tetrameres americana, respectively. Fifteen chickens were kept as uninfected controls. Every third week in a period of 12 weeks, 5-15 chickens were slaughtered and the proventriculi were examined for the presence of adult stages of T. americana. From day 21 post-infection, pooled feacal samples were examined for parasite eggs, whereas the weight gain of the chickens was monitored weekly. The parasite established the infection in similar rates in all the three groups, 9.5-15.2%, except on day 84 post-infection, when the establishment rate of the high-dose group was significantly lower (P < 0.005). The average worm burden increased with increasing dosages, though displaying the worm burden of the high-dose group as being roughly halved on day 84 post-infection, thus suggesting an expulsion of worms. Females were more abundant than males. The mean lengths of male and female specimens showed no significant differences between the groups. The egg output was also increased with increasing dosages with the earliest prepatent period of 38 days post-infection found in the high-dose group. Infected chickens exhibited no difference in weight gain in comparison with the controls. This study demonstrated that single infections with varying doses influenced the establishment rate and the worm burden but not the parasites egg excretion, worm size nor the weight gain and mortality of the final host.     

Maternal effects on embryonic and postembryonic growth in poultry

1. It was found that the environment determined by the hen, namely protein, fat and moisture, had no effect on the growth of the embryo during the first 14 d of development. 2. The amount of protein available influenced growth during the last week of incubation but the amount of fat and water had no effect. 3. The regression of embryo on egg weight for the pooled data of large (mean 62 g) and small (53 g) eggs was 0.85 +/- 0.06 at day 20. 4. Embryos from large eggs were significantly heavier than those from small eggs on day 20: this difference persisted to the end of the experiment at 56 d of age when it had increased to 100 g. 5. A 1-g difference in egg weight was reflected in about a 10-g difference in chick weight at 56 d of age.     

不同储存温度下鸡蛋表面和内部真菌动态研究

试验旨在通过检测商品鸡蛋在不同储存温度和时间蛋壳表面和内容物中真菌的数量和类别，了解真菌污染的动态变化，为改善鸡蛋储存条件并延长保鲜期提供参考。采取冀南某养殖小区不同养鸡场180枚新鲜鸡蛋，分别在25和4 ℃无菌环境下储存42 d，每7 d进行一次蛋壳和蛋液的真菌数量和类别检测。真菌数量检测参照国家标准GB 4789.15-2016；真菌种类鉴定采用形态观察结合rDNA-ITS序列分析法。试验结果显示，鸡蛋内外真菌检出率和数量均随储存时间延长而显著增长；蛋壳比蛋液真菌检出时间早、检出率高，蛋液处理组真菌检出率在21~28 d快速增长；在相同时间点，25 ℃处理组真菌数量（菌落数）显著高于4 ℃处理组，蛋壳处理组显著高于蛋液处理组（P<0.05）；在蛋壳和蛋液中共分离鉴定了168个真菌菌株，分属于18个种（属），其中优势属为青霉属（Penicillium sp.），优势种为草酸青霉（Penicillium oxalicum）；蛋液与蛋壳处理组的总菌落数和分离株数分别呈显著（P<0.05）和极显著相关（P<0.01）。综上，在采样养殖场环境下，鸡蛋的真菌污染普遍存在；样品真菌检出率和菌落总数均随储存时间延长呈明显上升趋势；冷藏（4 ℃）是防止鸡蛋真菌污染扩展的有效方法；蛋液的真菌污染可能主要来自蛋壳表面的真菌污染；样品鸡蛋污染真菌的多样性较高，其优势种属多为环境常在菌，但污染真菌中也有部分致病或产毒种类。     

Risk of Toxocara canis eggs in stray and domestic dog hair in Egypt

The aim of the study was to assess whether the hair of stray and domestic dogs in Egypt was contaminated with the eggs of the zoonotic parasite Toxocara canis, and also to identify risk factors for T. canis for contamination. Paired samples of hair and feces were collected from 53 stray and 47 domestic dogs, and hair samples were obtained from a further 11 stray and 9 domestic dogs. All samples were examined to identify T. canis eggs and, if eggs were found, their maturation stage. Eggs were identified in 26.6% of stray and 10.7% of domestic dog's hair samples. A significantly increased risk of embryonated T. canis eggs in hair samples was found in stray dogs (p=0.04), stray dogs had 3.18 (95% CI: 1.04-9.74) times the odds of having T. canis eggs present compared with domestic dogs. There was also a significant difference (p=0.02) between the mean quantity of eggs per gram in stray (77.6±6.54) and domestic (48.7±6.65) dog's hair. Fecal examination found a T. canis egg prevalence of 35.8% and 21.3% in stray and domestic dogs, respectively. As no domestic dogs which were positive from hair samples had negative fecal samples, this indicates that the presence of T. canis eggs in hair is probably due to self contamination. Two stray dogs had positive hair samples but negative fecal samples indicating that contamination may also be environmental. As both non-embryonated and embryonated T. canis eggs were found in the hair of domestic dogs, direct contact with dogs may be a potential risk factor for transmission of T. canis eggs to humans.     

肠炎沙门氏菌污染饲料对鸡蛋安全的影响

本研究选用160只60周龄白来航蛋鸡,随机分为4组,分别一次性采食30g添加了0、4.7×102、4.7×105、4.7×108cfu肠炎沙门氏菌(SE)的饲料,然后用特异性PCR法对试验鸡所产鸡蛋的不同部位进行SE检测,并观察记录生产性能。结果显示,对照组鸡蛋各部位均为阴性,试验组的蛋壳、壳膜、蛋黄、蛋白均能检测到SE,且随染菌量的增大,检出率增高。当摄入108cfu的SE时,会降低产蛋率,但对鸡蛋的表观性状没有显著影响,成为危害人类健康的潜在隐患。     

Review of induced molting by feed removal and contamination of eggs with Salmonella enterica serovar Enteritidis

As laying hens age, egg production and quality decreases. Egg producers can impose an induced molt on older hens that results in increased egg productivity and decreased hen mortality compared with non-molted hens of the same age. This review discusses the effect of induced molting by feed removal on immune parameters, Salmonella enterica serovar Enteritidis (SE) invasion and subsequent production of SE-contaminated eggs. Experimental oral infections with SE show molted hens are more susceptible to SE infection and produce more SE-contaminated eggs in the first few weeks post-molt compared with pre-molt egg production. In addition, it appears that molted hens are more likely to disseminate SE into their environment. Molted hens are more susceptible to SE infection by contact exposure to experimentally infected hens; thus, transmission of SE among molted hens could be more rapid than non-molted birds. Histological examination of the gastrointestinal tracts of molted SE-infected hens revealed more frequent and severe intestinal mucosal lesions compared with non-molted SE-infected hens. These data suggest that induced molting by feed deprivation alters the normal asymptomatic host-pathogen relationship. Published data suggest the highest proportion of SE-positive eggs is produced within 1-5 weeks post-molt and decreases sharply by 6-10 weeks and dissipates to the background level for non-molted hens by 11-20 weeks. Appropriate treatment measures of eggs produced in the fist 5 weeks post-molting may decrease the risk of foodborne infections to humans.     

A survey to detect Toxocara vitulorum and other gastrointestinal parasites in bison (Bison bison) herds from Manitoba and Saskatchewan

An egg count survey using environmental fecal samples obtained in spring or early summer was conducted to estimate the apparent prevalence of Toxocara vitulorum in unweaned bison calves and of other intestinal parasites in adult bison on 98 farms in Manitoba and Saskatchewan. Calf samples were pooled (maximum 5 samples per pool) by farm and positive pools were examined to determine individual T. vitulorum counts. Toxocara vitulorum eggs were found on 4 farms in Manitoba and none in Saskatchewan. Apparent herd-level prevalence estimates were 12% [95% confidence interval (95% CI): 3.4% to 28.2%] and 0% (95% CI: 0% to 5.7%) respectively. Samples from adult bison contained eggs/oocysts from trichostrongyle species, Eimeria sp., Monieza sp., Capillaria sp., Nematodirus sp. and Trichuris sp. in 100%, 95%, 72%, 13%, 13%, and 5% of herds, respectively. Strongyloides sp. were not found in any herd. Further studies are needed to assess parasite distribution patterns in bison and to evaluate the risk that T. vitulorum may pose to bison, cattle, and wildlife.     

First Production of Larvae Using Cryopreserved Sperm: Effects of Preservation Temperature and Cryopreservation on European Eel Sperm Fertilization Capacity

Sperm cryopreservation is a useful tool in captive fish reproduction management, that is to synchronize gamete production, especially in the case of species as the European eel, where the time of female spawning readiness is unpredictable. Several protocols to cryopreserve sperm of this species have been described, but until recently fertilization trials were not feasible. This study evaluated the effect of cold storage of diluted sperm prior to fertilizations and tested whether a previously defined protocol for European eel sperm cryopreservation can be successfully applied in fertilization trials to produce viable offspring. In our experiment, the sperm motility was evaluated after the extraction and the best samples were selected and pooled. Until stripping of eggs and fertilization, diluted sperm samples were maintained at either 4 or 20°C, or cryopreserved, following existing protocols. Fertilization of two egg batches was attempted. Diluted sperm caused a similar percentage of fertilized eggs and a similar number of embryos and larvae, independently of storage temperature (4 or 20°C). The cryopreserved sperm resulted in a lower percentage of fertilized eggs, but embryos developed and a few larvae (‘cryolarvae’) were obtained 55 h after fertilization in one of the two egg batches. This result evidences that the tested cryopreservation protocol is applicable for eel reproduction management, although improvements will be required to enhance fertilization success.