Disinfection Of Eggs Research Articles

Diferentes desinfetantes sobre a contaminação e desempenho da incubação de ovos de avestruz

From the moment of laying, eggs come into contact with microorganisms that adhere to the shelland disinfection is the process that reduces contamination by preventing them from penetrating the shell and invading the egg's internal content, however, different active principles can result in effects several. The objective was to evaluate the efficiency of different active principles in the disinfection of ostrich eggs on contamination andthe productive indexes of incubation. 16 eggs were used, distributed in two disinfectant active ingredients (quaternary ammonia and formaldehyde) in a completely randomized design with 8 replications. Contamination of the eggshell was evaluated by microbiological analysis on the surface of the eggshell after disinfection. The productive indexes of the incubation were evaluated by means of the index of weight loss of the egg (%), mortality rate (%), embryology (%) and hatchability (%). There was no significant difference (p> 0.05) between the active ingredients used in terms of disinfection capacity and productive indexes of incubation. It is concluded that bothactive ingredients are efficient in the disinfection of eggs, ensuring the control of contamination on the surface of the egg shell during the storage and incubation processes, in addition to not affecting the parameters of the incubation.

Inactivation of helminth eggs in an electro-Fenton reactor: Towards full electrochemical disinfection of human waste using activated carbon

The disinfection of helminth eggs and Escherichia coli contaminated aqueous solutions, was studied using an electro-Fenton reactor equipped with a polarized activated carbon (AC) packed bed and two chambers loaded with cation exchange resins. Experiments using different arrangements and operation conditions, revealed that effective elimination of Escherichia coli takes place in all electrochemical disinfection tests. For the more resistant helminth eggs however, adsorption, electro-oxidation and electro-Fenton experiments showed retention within the reactor and pathogen inactivation values of 0, 16, and 25%, respectively. Using helminth eggs concentration data in different sections of the reactor, optical microscopy analysis and an exploratory computer simulation, differences in the disinfection performance were explained and new recirculation and flow direction and polarization switching operation schemes were defined. The corresponding experiments revealed that the effective coupling between adsorption and electro-Fenton phenomena, all along the AC packed bed compartment, results in 100% inactivation of helminth eggs.

FEATURES OF PROCESSING OF WATERFOWL EGGS DURING THE INCUBATION

The purpose of this work was to conduct a comparative evaluation of existing disinfectants for their use in the second half of incubation for irrigation of waterfowl eggs. Methods. The study was conducted at the State Poultry Research Station of NAAS on hatching eggs of ducks and incubation wastes. Pre-incubation disinfection of eggs was carried out by irrigation with 5.0% solution of "Lasept-forte". Eggs were incubated according to standard regimes in modernized laboratory incubators ILU-F-0.3 and ILB-0.5. According to the requirements of the current standard for the technological process of incubation of duck eggs from the 13th day of incubation air cooling of eggs twice a day (morning and evening) for 10-15 minutes was carried out, and from the 20th day – a wet one. Modern disinfectants in various concentrations were used to irrigate duck eggs during incubation. Irrigation of duck eggs of the control group was performed with clean water. According to the results of research, the efficiency of irrigation of eggs with «Lasept-forte» and «Brovadez Plus» has been proved, and their optimal concentrations have been selected. It was found that the use of 0.5 % "Lasept-forte" or 0.05 % "Brovadez plus" for irrigation of duck eggs from the 20th day of incubation is desirable because it increases the results of incubation by 1.5- 2.5% due to the improvement of the sanitary condition in the incubator and the reduction of embryo death in the later stages of development. The pathological autopsy of incubation wastes showed that the category of waste "dead" (embryos that died after 25 days of incubation) was in the control group at 7.0%, in the experimental 6.0-6.5 %. At the same time, at the autopsy of the “dead” from these groups, there were signs of death from damage to eggs by microflora and fungi. In the control group, 64.3 % of deaths had such symptoms, in the first experimental group - 53.8 %, in the second experimental group - 33.3 %, which also proves the effectiveness of the means used.

Модификация метода профилактической обработки икры нерки йодинолом от вируса инфекционного некроза гемопоэтической ткани на ЛРЗ Камчатки

In world practice, at salmon hatcheries, eggs are disinfected with iodophor after fertilization, because the substance - the carrier of iodine is pyrrolidone, which has toxic properties for embryos and is capable of destroying biological membranes. In Russia, eggs are also disinfected after fertilization, but using iodinol. In this disinfectant, active iodine is in the form of an iodine- starch complex, which is safe for biological membranes, and can be used (concentration of active iodine 100 mg/l, pH within 7) instead of water during fertilization of eggs. On the example of long-term data of Malkinskii Hatchery (MH), it was shown that the mortality of egg and juveniles does not increase from the egg disinfection directly with iodinol during fertilization. The experimental studies of 2017 did not show any significant differences in the mortality of egg and juveniles at the MH after egg fertilization in water and in iodinol under other similar conditions of rearing. The disinfectant has no toxic effect on biological membranes and can be recommended for the disinfection of salmon egg directly in the process of fertilization for the prevention of fish viral and bacterial diseases. Iodinol is a promising drug for the fight against diseases with vertical transmission of the pathogen inside the egg. The proposed modification of the method of egg treatment can significantly reduce the consumption of the disinfectant and manipulations with eggs.

Disinfection of almaco jack ( Seriola rivoliana Valenciennes) eggs: Evaluation of three chemicals

Almaco jack (Seriola rivoliana Valenciennes) is an excellent candidate for aquaculture due to its fast growth rate and high market value. While S. rivoliana have adapted well to captivity, survival at early life stages can be improved to increase profitability during production. A wide range of variables cause larval mortalities but high bacterial loads in rearing tanks are often correlated with these losses. The aim of this study was to investigate the effect of egg disinfection on bacterial load and hatch rate of S. rivoliana. Disinfectants tested included formalin (F100 and F200; 100 and 200 mg/L, respectively, for 60 min), hydrogen peroxide (HPO; 300 mg/L for 10 min) and peracetic acid/hydrogen peroxide (PAA/HPO; 15.7 mg/L/39.6 mg/L for 1 min). Concentrations and contact times were determined based on current use in marine aquaculture and preliminary trials. Eggs treated with HPO and F100 had significantly higher hatch rates than the untreated control group. All treatments significantly decreased total Vibrio counts compared to untreated eggs; however, total bacterial counts were only decreased following treatments with PAA/HPO and F200. To prevent egg mortality due to bacterial overgrowth, consideration should be given to the use of surface disinfection using HPO or F100. Future studies should investigate the use of peracetic-based products at lower doses.

Impact of Hatching Egg Disinfection on Hatching Characteristics and Chick Embryos

Four thousand two hundred hatching eggs were obtained from Bandarah chicken to evaluate the effect of chemical and natural egg disinfectants and fumigation on egg weight loss, embryonic mortality, hatchability, hatch time, chick weight and chick weight loss. Three incubation trials were done; each one contained 1400 hatched eggs and divided into fourteen treatments (100 eggs per each). First treatment (T1) was used as control without any treatment, eggs of second treatment (T2) were dipped in water and third treatment in alcohol, whereas T4, T5, T6, T7 treated egg groups were dipped in chemical disinfectant (sodium chloride, betadine, hydrogen peroxide, virkon S). Egg of T9, T10, T11, T12, T13 and T14 groups were dipped in natural disinfectants (oregano, cumin 02 and 04 % and oregano+ cumin01 and 02), respectively. The thickest eggshell (031mm) was recorded for betadine group in infertile eggs compared with those for formaldehyde fumigation and oregano+cumin 01% oregano+cumin 01% group (035mm) compared with all other treatment groups. Formaldehyde fumigation recorded the worst and highest significant percentage of embryonic mortality (1795%). Highest significant percentages for hatchability of fertile egg were recorded in egg groups with oregano 02 and 04% (9687 and 9576%), cumin 02 and 04 % (9551and 9715%) and oregano+cumin01 and 02% (9619 and 9615%), respectively.

Properties of hens’ eggs after surface irradiation by nanosecond electron beam

There are presented some details of the technology of surface disinfection of the fresh eggs. Irradiation experiments were carried out by means of the pulsed repetitive nanosecond accelerator URT-0.5 (electron energy of up to 500 keV, a pulse duration of 50 ns, pulse repetition rate up to 200 pps, which significantly reduce the costs of the irradiation in comparison with high-energy electrons (several MeV) or γ-radiation.The determination of the distribution of the absorbed dose in the depth of the polyethylene was conducted by the gray wedge method. Measurement of the electron beam dose on the surface of the shell and under the shell, as well as beneath the absorber layer (polyethylene 80 μm thick) was also performed by a film dosimeter. The electron average dose rate on the egg surface was 200 Gy/pulse and the instantaneous dose rate was 4 GGy/s. The non-uniform distribution of the electron beam current density on the output foil was ±15%.Thermoluminescent dosimeters, TLD-500, were used to determine the distribution of the bremsstrahlung dose inside hens’ eggs. It has been established that for nanosecond electron beam irradiation with dose higher than 5 kGy sufficient for complete disinfection on the hens’ egg surface, due to bremsstrahlung, the dose inside it will not exceed 8 cGy. This dose value should not lead to biological changes in the white or yolk.Dose 5 kGy does not influence the observed shell surface; there are no changes on the egg surface according to scanning electron microscope data. For heavy doses, rounded areas of the surface relief are observed.Data from energy-dispersive X-ray spectroscopy analysis for high dose show a significant increase in the amount of phosphorus and especially calcium in the shell and some reduction in the amount of oxygen, most likely due to change in the surface distribution of elements in the shell.

The effect of neutral electrolyzed water as a disinfectant of eggshells artificially contaminated with Listeria monocytogenes.

Neutral electrolyzed water (NEW) was tested as a disinfectant against Listeria monocytogenes on the surface of table eggs. Eggs were collected from a single Bovans White flock and were exposed to L. monocytogenes. Artificially contaminated eggs were divided into three different treatment groups: NEW, 2% citric acid solution (CAS), and saline solution (SS). To evaluate the bactericidal effect, the Mexican norm for antimicrobial activity determination protocol was performed. The observed bactericidal effect was compared against those obtained from CAS and SS. Bacterial cells present on the eggshells were quantified. NEW exhibited a significantly higher bactericidal effect than CAS when evaluated on the surfaces of chicken eggshells (6.11 log10CFU/ml reduction in vitro and a 2.18 log10 CFU/egg reduction on eggs vs. 1.06 log10CFU/ml in vitro reduction and 1.74 log10CFU/egg). Additionally, CAS was found to react with the carbonate egg shield, resulting in a loss of cuticle integrity. Mineral content of NEW‐treated eggshells was similar to SS‐treated eggshells; however, CAS‐treated eggshells showed a significant decrease in phosphorous concentration compared to NEW treatment. In this study, we demonstrated the effect of NEW and CAS on the integrity of the L. monocytogenes wall using transmission electron microscopy. To the best of our knowledge, this is the first report of the effect of NEW against L. monocytogenes on eggshells. Our results show that NEW is a viable alternative solution for the disinfection of table eggs that does not affect the cuticle or shell.

Disinfection of Fertile Eggs of Free-Range Poultry with Essential Oils

SUMMARY The effect of the disinfection of fertile eggs of free-range poultry with essential oils from Cymbopogon flexuosus and Lippia rotundifolia was evaluated. The treatments applied to the eggs were (v v-1): 1% essential oil from C. flexuosus (CF), 1% essential oil from L. rotundifolia(LR), 0.1% CF + LR, and 0.1% quaternary ammonia (QA) (positive control). The eggs were incubated for 21 days, the birds from hatched eggs were counted and weighed, and not hatched eggs were opened and examined macroscopically to determine egg fertility, and embryonic death time. The antimicrobial action of the essential oils was determined through quantitative analyses, considering aerobic mesophylls, filamentous fungi, yeasts, and total coliforms. Mortality was high in the treatments, especially in the treatment with essential oil from C. flexuosus. The highest hatchability was found in the treatment with QA. The treatments with singly or combined essential oils were more efficient in decreasing microbial count than QA. The essential oils from C. flexuosus and L. rotundifolia reduced the microbial load of fertile eggs of the free-range poultry evaluated.

The use of nanosecond electron beam for the eggs surface disinfection in industrial poultry

Development of the technology bases of egg disinfection using surface irradiation is executed by the nanosecond electron beam. Experiments on shell eggs irradiation using the frequency nanosecond URT-0.5 accelerator were made. Determination of absorbed dose distributionwas executed. In case of irradiation by the electron beam with absorbed dose level 5 kGy, it is enough for the full disinfection of the surface and pores of egg shell. The absorbed dose in the egg at the expense of bremsstrahlung will not exceed 0.08 Gy which can’t have essential action on protein. Irradiation of shell eggs batch in plastic package of 100 pieces pledged in an incubator together with an inspection lot of not irradiated egg was made. The percent of eggs deductibility and chickens survival of pilot and control batches were identical, indicating that there was no significant radio biological effect from irradiation of egg internal structures. The received chickens were grown up within the 5 weeks. It is established that the chickens who are grown up from the irradiated egg have no essential differences in development.

Systems toxicology approach for the assessment of zebrafish cardiotoxicity

Disinfection of non-hardened Lota lota, Salmo trutta, and Thymallus thymallus eggs with iodophor solution was investigated. The following results were obtained: 5 min after fertilization, non-hardened eggs could be disinfected with ≤ 1% iodophor solution (≤ 135 mg/l active iodine) diluted in 0.75% NaCl without negative effects on the rate of eyed stage embryos, the rate of hatched larvae, and the rate of misshaped larvae. After iodophor disinfection, the percentile mass increase due to water hardening was initially suppressed but compensated during later phases of the hardening process. As investigated in L. lota and S. trutta, disinfection of non-hardened eggs in iodophor solution diluted in water had a higher toxicity on the percentage of eyed stage embryos than iodophor solution diluted in 0.75% NaCl. Measurement of egg internal iodine concentrations in S. trutta and Thmallus thymallus demonstrated that iodine entered the egg in < 5 min and that iodine was found in the eggs in comparable concentrations to the disinfection solution. There were no differences in the egg internal iodine concentrations when eggs were disinfected in iodophor solution diluted in 0.75% NaCl or in iodophor solution diluted in water.

Increasing Iodine Concentrations during Landlocked Fall Chinook Salmon Egg Disinfection Decrease Bacterial Numbers with No Impact on Egg Survival

AbstractEgg disinfection is an important practice that prevents potential disease transfer, but currently allowable disinfection regimes do not completely eliminate external egg membrane microbes. In this experiment, newly fertilized and water‐hardened landlocked fall Chinook Salmon Oncorhynchus tshawytscha eggs were submersed for 10 min in povidone‐iodine solutions containing 0, 100, 200, and 400 mg/L active iodine. External egg bacterial numbers (CFUs) were quantified after each disinfection treatment, and egg survival (%) was calculated at the eyed stage. All of the disinfection treatments significantly reduced CFUs compared with untreated controls. However, eggs from the 400‐mg/L iodine treatment had significantly lower CFUs (2.20 ± 0.59 [mean ± SE]) than the 100‐mg/L (10.43 ± 8.01) and 200‐mg/L (8.10 ± 1.51) treatments. Percent survival was not significantly different among any of the treatments; survival was 18.86 ± 5.17%, 19.17 ± 4.76%, and 20.16 ± 5.27% in the eggs subjected to 100 mg/L, 200 mg/L, and 400 mg/L iodine, respectively. These results indicate that 10‐min treatments of 400 mg/L active iodine on landlocked fall Chinook Salmon eggs provide the most microbial reduction with no effect on subsequent egg survival.

Phenotypic effects of antibiotic-induced axenity and egg disinfection in early larval European seabass (Dicentrarchus labraxL.)

In the present study, the hypothesis that the difference in axenic conditions in the incubation and rearing environment of European seabass larvae induces size and shape effects on the specimens is tested. This difference is studied between xenic and axenic seabass larvae of DAH (day after hatching) 0, 5, 11 and 15. The axenic rearing protocol involves an egg disinfection with glutaraldehyde after the primary one with iodine in the hatchery, and the hypothesis that this secondary disinfection induces size and shape effects is also tested. In order to accomplish this, three egg and larvae treatments are included: “DA” (disinfected axenic), “DX” (disinfected xenic) and “NX” (nondisinfected xenic). Regarding the effect of antibiotic-induced axenity, DA larvae exhibited larger bodies than both DX and NX on DAH 5 and 11. They also had a smaller yolk sac than DX at hatching, but consumed it slower. Towards the end of the experiment, DA larvae were thicker, but slightly more curved than DX and NX, which may be an abnormal shape, or a slightly more advanced ontogenetic stage. As far as egg disinfection, it had significant but very moderate shape effects on DAH 5 and 11, and disinfected larvae consumed their yolk sac faster. To the best of our knowledge, this study is one of the first to illustrate the subtle but significant size and shape effects caused by antibiotic-induced axenity and secondary egg disinfection in the early larval stages, which suggest the existence of bacterial mechanisms that play a phenotypic role.

Effect of Egg Disinfection by Silver Nanoparticles on Eggshell Microbial Load, Hatchability and Post-hatch Performance of Quail Chicks

Effect of Egg Disinfection by Silver Nanoparticles on Eggshell Microbial Load, Hatchability and Post-hatch Performance of Quail Chicks

The Effects of Using Garlic Extract for Quail Hatching Egg Disinfection on Hatching Results and Performance

ABSTRACT This experiment was carried out to determine the effects of using garlic extract (Allium sativum) as an alternative to formaldehyde for the disinfection of hatching eggs on hatching traits and growth performance of quails. Four treatments, with 240 hatching eggs each, were evaluated: egg immersion in two different levels (2.5% and 5.0%) of garlic extract (garlic-1, garlic-2), formaldehyde fumigation (positive control), and eggs not submitted to disinfection (negative control). Mid-term and late embryomortality, pipped egg, and culled chick rates were not influenced by the (p>0.05). The highest (p 0.05). The results obtained for hatching traits and live performance parameters indicated that the immersion of eggs in garlic extract may be used as an alternative to formaldehyde fumigation for the disinfection of hatching quail eggs.

Maintenance of Fish Health in Aquaculture: Review of Epidemiological Approaches for Prevention and Control of Infectious Disease of Fish.

Aquaculture is rapidly growing part of agriculture worldwide. It makes up around 44 percent of total fish production globally. This increased growth of production is achieved despite facing many challenges in the aquaculture environment. Among production limiting challenges, the infectious disease takes the lion share by causing multibillion-dollar loss annually. To reduce the impact of the fish disease, it is necessary to address health constraints based on scientifically proven and recommended ways. This review aims at pointing out some of the best approaches to prevention and control of infectious disease in aquaculture. Among the effective prevention and control strategies, vaccination is one of the key practices. Types of vaccines for use in fish include killed vaccines, attenuated vaccines, DNA vaccines, recombinant technology vaccines, and synthetic peptide vaccines. Administration techniques of vaccines in fish include oral, injection, or immersion methods. Antibiotics are also in use in aquaculture despite their side effects in the development of drug resistance by microorganisms. Biological and chemical disease control strategies such as using probiotics, prebiotics, and medicinal plants are widely in use. Biosecurity measures in aquaculture can keep the safety of a facility from certain disease-causing agents that are absent in particular system. Farm-level biosecurity measures include strict quarantine measures, egg disinfection, traffic control, water treatments, clean feed, and disposal of mortalities. In conclusion, rather than trying to treat every disease case, it advisable to follow a preventive approach before the event of any disease outbreaks.

ПРИМЕНЕНИЕ ПРЕПАРАТА ЙОДЕЗ ДЛЯ СНИЖЕНИЯ БАКТЕРИАЛЬНОЙ ОБСЕМЕНЕННОСТИ ТОВАРНЫХ ЯИЦ

In conditions of modern industrial poultry eggs are often contaminated with enteropathogens, on the surface of the shell there are such microbes as Salmonella, staphylococci and streptococci, intestinal and Pseudomonas aeruginosa sticks, Proteus, fungi, etc. Most industrial poultry farms are integrated enterprises operating on the principle of «vertical communication », which is characterized by significant concentration of poultry in limited areas, this in turn leads to sharp increasing of number of microorganisms on the egg surface, as well as an increase of their pathogenicity. The search for new effective and cost-safe drugs that meet all modern requirements is an actual and economically justified scientific direction. The aim of the present research was to develop effective modes and technologies of disinfection of eggs shell surface by preparation «Jodеs». As a result of the conducted research, high contamination of the shell by microflora, including CGB and mold fungi, was established. The regimes and technology of disinfection of eggs using the disinfectant «Jodеs» in 1% concentration were developed: with small – scale irrigation (wet disinfection method) – exposure for 3 hours; and full immersion for few seconds. It is established that the drug «Jodеs» in 1% concentration effectively sanitize the surface of the shell. Using this drug and compliance with its application can achieve protection of poultry from unwanted microflora.

Impact of egg disinfection of hatching eggs on the eggshell microbiome and bacterial load

Disinfection of hatching eggs is essential to ensure high quality production of broilers. Different protocols are followed in different hatcheries; however, only limited scientific evidence on how the disinfection procedures impact the microbiome is available. The aim of the present study was to characterize the microbiome and aerobic bacterial load of hatching eggs before disinfection and during the subsequent disinfection steps. The study included a group of visibly clean and a group of visibly dirty eggs. For dirty eggs, an initial wash in chlorine was performed, hereafter all eggs were submitted to two times fumigation and finally spray disinfection. The eggshell microbiome was characterized by sequencing of the total amount of 16S rRNA extracted from each sample, consisting of shell surface swabs of five eggs from the same group. In addition, the number of colony forming units (cfu) under aerobic conditions was established for each disinfection step. The disinfection procedure reduced the bacterial load from more than 104 cfu (initially visibly clean eggs) and 105 cfu (initially visibly dirty eggs) to less than 10 cfu per sample after disinfection for both groups of eggs. The microbiome of both initially visibly clean and initially visibly dirty eggs had the highest abundances of the phyla Firmicutes, Proteobacteria and Bacteroidetes. Within the phyla Firmicutes the relative abundances of Clostridiales decreased while Lactobacillus increased from before to after final disinfection. In conclusion, the investigated disinfection procedure is effective in reducing the bacterial load, and by adding a chlorine wash for initially visibly dirty eggs, the microbiome of initially visibly clean and initially visibly dirty eggs had a highly similar microflora after the final disinfection step.

Assessment of the effect of selected substances used for disinfection of hatching eggs on hatching results in chickens

The aim of the study was to investigate whether egg disinfectants have a toxic effect on the tissues of the developing chicken embryo. The basic active ingredients of the disinfectants tested were quaternary ammonium compounds (Amino-Steril); stabilized peracetic acid and hydrogen peroxide (Oxydion); glutaraldehyde, didecyldimethylammonium chloride, quaternary ammonium compounds and benzyl-C12-C16-alkyldimethyl (Viron FF); and stabilized hydrogen peroxide (Hydro-Clean). The tests were performed on hatching eggs from Ross 308 parent stock. The potential adverse effects of aqueous solutions of the disinfectants were tested in vitro using the Hen’s Egg Test – Chorioallantoic Membrane (HET-CAM). The results were confirmed in in vivo tests by analysing the hatchability of disinfected eggs. In the in vitro tests, aqueous solutions of the disinfectants with concentrations of 1%, 0.5%, 0.25% and 0.125% were spotted onto previously prepared chorioallantoic membranes of live eight-day-old chicken embryos (n = 8 embryos/disinfectant/concentration). The toxicity of the substances was assessed on the basis of the occurrence of hyperaemia, haemorrhage, and coagulation of the blood vessels of the membrane after 0.5, 2 and 5 minutes, using the 21-point Luepke scale. The in vivo testing consisted of two experiments conducted under production conditions, using eggs from flocks in the peak (37th week of life) and the final (54th week) laying periods. The eggs were sprayed with a 1% aqueous solution of disinfectant (400 eggs/disinfectant/experiment) about 2 hours before incubation. Hatching results, the stage of embryonic development at the time of death and any cases of infection were evaluated. The HET-CAM tests showed that the 1% solutions of the disinfectants induced strong (Hydro-Clean), moderate (Oxydion and Amino-Steril) and weak (Viron FF) reactions, while the 0.125% concentration produced a weak reaction or none. Analysis of hatching results showed that they were not affected by the disinfectants. However, in the case of laying hens in their final production period, spraying with aqueous solutions of each agent reduced losses due to early embryo mortality. In conclusion, the disinfectants tested can be safely used in poultry hatcheries

Assessment of apparent effectiveness of chemical egg disinfectants for improved artificial hatching in Oreochromis karongae (Pisces: Cichlidae)

Oreochromis karongae is one of the three key Tilapia species locally known as ‘Chambo’ which is endemic to Lake Malawi. The species is favored by consumers and due to high demand its catches have significantly declined over time. Aquaculture holds the potential to supplement catches as well as produce seed for restocking purposes. However, seed production of O.karongae in artificial hatcheries has registered little success due to high egg and fry mortalities. Therefore, a study was conducted to compare the apparent effectiveness of three chemical egg disinfectants in an attempt to improve hatching success and reduce fry mortality in O. karongae in an artificial re-circulating incubation system at the National Aquaculture Center, Domasi, Malawi. Batches of 200 stage II eggs were immersed for 5 minutes in 50ml solutions of (1) 50mg/l Potassium Permanganate, (2) 500mg/l Formalin, (3) 1000mg/l Sodium Chloride, (4) 5000mg/l Sodium Chloride, while treatment (5) was a control without any chemical treatment. Each treatment was replicated three times in 1.2 L plastic incubation jars with continuous water flow rate of 0.17 l/s operated at 10% daily water replacement. There was significantly low total mortality and high hatchability in treatments (1), (2) and (3) than (4) and (5) (p<0.05). The results provided evidence that pre-incubation egg treatment using chemicals has potential to significantly reduce mortalities and increase fry production in an artificial re-circulating incubation system. It is recommended, based on the findings that lower concentrations of sodium chloride, being a safer and less toxic chemical can be used for disinfecting O.karongae eggs. Future studies should focus on undertaking a toxicity test with various levels of the chemical disinfectants to identify optimum doses. This should be coupled with microbiological assays to validate the apparent effectiveness found in this study and identify the key microbial species that are responsible for mortalities during incubation of O.karongae eggs in a re-circulating system. Key words: Egg, disinfectants, incubation, recirculation, hatchability, egg treatment, mortality, Oreochromis karongae