Fish bacterial Diseases

This review examines the potential of essential oils (EOs) as natural additives in aquaculture, emphasizing their antimicrobial, antioxidant, and immune-boosting effects that can improve fish health and resilience. EOs, sourced from plants, offer a sustainable alternative to synthetic chemicals, promoting growth, feed efficiency, and disease resistance. However, challenges such as optimizing dosages, delivery methods, and cost-efficiency remain. Techniques like microencapsulation may improve EO stability and release, but more research is needed to refine these methods and understand how EOs affect fish health and the environment. Overcoming these challenges will enable a more sustainable and eco-friendly aquaculture industry.

Florfenicol is a semisynthetic antibacterial agent with common features to that of thiamphenicol, especially with regard to the fact that both are absolved from dose-independent dreadful side effects of chloramphenicol on bone marrow of humans. Florfenicol has shown potent activity against several bacteria which are pathogenic to fish (Lunestad & Samuelsen, 2008). Pharmacokinetic features of florfenicol have been studied in different fish species including

Background and Aim: Streptococcosis, caused by Streptococcus agalactiae, is a significant disease in tilapia farming that results in substantial economic losses. While vaccination is the most effective method for prevention, current vaccines face challenges when administered orally or through immersion, primarily due to poor absorption and degradation in the fish’s digestive system. Nanotechnology offers new ways to improve vaccine delivery and effectiveness. This review compares two nanoparticle (NPs)-based systems – nanoemulsions and silica NPs (SiNP) – for delivering vaccines to tilapia. Nanoemulsions are small, stable droplets that protect the vaccine and help it stick to mucosal surfaces, making them more effective in triggering immune responses. SiNP are highly stable and can protect vaccines under harsh conditions but still face challenges in particle size and vaccine loading. The review highlights important factors, including particle size, stability, and surfactant composition, that affect the vaccine’s effectiveness. In practical terms, nanoemulsions are more suitable for use in Indonesia’s tropical aquaculture settings because they are easier to apply, more stable, and more effective in their current formulations. Further research is needed to improve both systems, especially to ensure long-term safety, improve delivery to mucosal tissues, and reduce production costs. Nanotechnology-based vaccines have a strong potential to improve fish health and reduce antibiotic use in aquaculture.


Keywords: fish health, mucosal vaccine, nanoemulsion, nanovaccine, silica nanoparticles, Streptococcus agalactiae, tilapia.

Bacteriological examination of milk samples is a prerequisite for pathogen-specific therapy and aids in limiting antimicrobial resistance. The aims of this study were to establish a standardized scheme for reliable Streptococcus uberis identification in routine diagnosis and to evaluate the accuracy of conventional tests and growing patterns of Strep. uberis on a selective medium (modified Rambach agar medium, MRAM) using 16S rRNA gene sequencing analysis as a reference method. We obtained isolates of presumptive Strep. uberis (n = 336) from quarter milk samples of dairy cows with intramammary infections and classified the isolates into 2 clusters using biochemical characterization. In cluster 1 (n = 280), cocci grew as non-hemolytic colonies, hydrolyzing esculin, carrying no Lancefield antigen (A/B/C/D/G) or Christie Atkins Munch-Petersen factor, and their growth was inhibited on an Enterococcus agar. Production of β-d-galactosidase on MRAM was shown by 257 of the cluster 1 isolates (91.79%), and 16S rRNA gene sequencing verified 271 (96.79%) of the isolates to be Strep. uberis. In 264 isolates (94.29%), MRAM agreed with the sequencing results. In cluster 2 (n = 56), isolates showed different characteristics: 37 (66.07%) were β-d-galactosidase-positive, and based on 16S sequencing results, 36 (64.29%) were identified correctly as Strep. uberis using biochemical methods. Identification success in this group differed significantly between routine diagnosis and MRAM application: MRAM agreed with sequencing results in 47 isolates (83.93%). To identify Strep. uberis and differentiate it from other lactic acid bacteria in routine diagnosis, we suggest using catalase reaction, hemolysis, esculin hydrolysis, and growth on enterococci agar. Isolates that show a typical biochemical profile can be identified satisfactorily with these tests. For Strep. uberis isolates with divergent patterns, application of MRAM as a follow-up test increased the diagnostic accuracy to 94.64%.

Diplostomum species are the parasites responsible for diplostomiasis in fish which may cause ocular diseases such as blindness, eyefluke, severe ocular disease and opacity of the lens. The parasites use many organisms including fish as host. African catfish is one of the widely distributed fish species in tropical Africa and has become one of the most important culturable fish species in Africa especially in Nigeria. This study examined the occurrence of Diplostomum species in farm raised African catfish in Oyo state. The study was carried out in Oyo State, Nigeria. A total of 216 eye samples were collected from 108 fishes in 36 farms. The eye lens and vitreous were examined for the presence of Diplostomum species. The data obtained were analysed using descriptive statistics and regression analysis to the relationship between the eye size and parasite occurrence. The result shows that 16.20% of the samples had Diplostomum species. Males had higher occurrence (23.53%) than the female...

Diplostomum turu parazitler, baliklarda korluk, siddetli goz hastaligi, goz nezlesi ve lensin matlasmasi gibi goz problemlerinden sorumlu parazitlerdir. Afrika yayin baligi, Afrika’da ozellikle Nijerya’da kultur balikciginda yaygin bir sekilde yetistirilen en onemli tropikal balik turu olup Diplostomum turu parazitler bu baliklari konakci olarak kullanirlar. Bu calisma Nijerya’nin Oyo Eyaletinde ciftlik sartlarinda yetistirilen yayin baliklarinda (Clarias gariepinus) Diplostomum turu parazitinin varligini arastirmak amaciyla yapilmistir. Toplam olarak 36 balik ciftliginden temin edilen 108 baliga ait 216 adet goz arastirma materyali olarak kullanilmistir. Arastirma materyali olarak kullanilan gozlerden elde edilen lensler ve vitreous’lar Diplostomum turleri varligi acisindan incelendi. Elde edilen verilerden goz boyutu ve parazit gorulme orani arasindaki iliski regresyon analizi ile istatistiksel olarak analiz edildi. Sonuc olarak arastirmada kullanilan orneklerin %16.20’sinde Diplo...

Yersiniosis or Enteric red mouth disease (ERM) is an infectious bacterial disease that causes high mortality and economic losses in aquaculture industry. Yersiniosis has been spread in most of the Iran's provinces in last year's. Mazandaran province has the second grade of rainbow trout production in Iran and in Mazandaran province, the most rainbow trout produce in Haraz zone. Therefore, environmental parameters responsible for Yersiniosis were studied in Haraz zone (Mazandaran, Iran). Some Physical and chemical parameters of rainbow trout farms including: Nitrite, Nitrate, Ammonia, Total dissolved solid (TDS), Temperature, Dissolved oxygen (DO) and pH were measured monthly in 10 farms, one year duration. Also, liver and kidney of 1200 rainbow trout with clinical signs (410 samples) and without clinical signs (790 samples) were cultured to ensure for Yersiniosis outbreak. Effective parameters in Yersiniosis were temperature, pH increase, fish size and season. In addition, Yersinia ruckeri were isolated from 20% of fishes with clinical signs and 10% of fishes without clinical signs.

Parasitic infections threaten the endangered Oreochromis jipe and other ichthyic populations in Lake Jipe, thereby hindering conservation efforts. Initiatives have been made to farm O. jipe as a conservation strategy. To develop effective conservation approaches and ensure the species' survival in its natural habitat and aquaculture systems, it is imperative to understand the diverse parasites in these habitats. Consequently, this cross-sectional study was conducted to determine parasitic loads in tilapias from selected farms and Lake Jipe. A total of 111 fishes were collected (76 farmed, 35 from the lake), comprising 66 O. jipe, 34 Oreochromis niloticus and 11 hybrids of O. jipe and O. niloticus. The fish were euthanized, necropsied and examined for parasitic infections via visual inspection and light microscopy. Out of 111 fishes examined, 58 (52.3%) were infected with 212 parasites, including 135 (63.7%) and 77 (36.3%) from farm and lake habitats, respectively. The prevalence of parasitic infections in fish from the lake and farm habitats was 68.6% and 44.7%, respectively. The most frequently occurring parasite genera identified were Diplostomum (30.63%), Acanthocephalus (20.7%), Dactylogyrus (9.9%) and Contracaecum (2.7%), with mean intensities of 2.9, 3.7, 1.9 and 1.7, respectively. Contracaecum and Camallanus were exclusively found in fish from Lake Jipe, while Euclinostomum and Gyrodactylus were only observed in farmed fish. O. jipe had the highest prevalence of parasitic infections (59.1%), followed by O. niloticus (44.1%) and hybrids (36.4%) (p > 0.05). In conclusion, the examined fishes were infected with diverse parasites, which have both public health concerns (Euclinostomum and Acanthocephalus) and economic significance (Dactylogyrus and Gyrodactylus). Consequently, it is imperative to enhance public awareness and enforce biosecurity measures to mitigate potential health risks and to improve the productivity of the pond culture system and lake ecosystem. These measures will help reduce parasite dissemination and promote sustainable fish production and populations. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Lactic acid bacteria have become a major source of concern for aquaculture in recent decades. In addition to true pathogenic species of worldwide significance, such as Streptococcus iniae and Lactococcus garvieae , several species have been reported to produce occasional fish mortalities in limited geographic areas, and many unidentifiable or ill-defined isolates are regularly isolated from fish or fish products. To clarify the nature and prevalence of different fish-associated bacteria belonging to the lactic acid bacterium group, a collection of 57 isolates of different origins was studied and compared with a set of 22 type strains, using amplified rRNA gene restriction analysis (ARDRA). Twelve distinct clusters were delineated on the basis of ARDRA profiles and were confirmed by sequencing of sodA and 16S rRNA genes. These clusters included the following: Lactococcus raffinolactis , L. garvieae , Lactococcus l ., S. iniae , S. dysgalactiae , S. parauberis , S. agalactiae , Carnob...

Globally, parasitic infections hinder aquaculture productivity and sustainability. Improper water quality parameters reduce fish immunity, make them susceptible to parasites, and enhance parasitic proliferation in culture systems. Subsequently, this study aimed to determine the prevalence and intensity of ecto-and endo-parasite infesting Oreochromis niloticus in varying water quality in aquaculture systems in Kericho, Bomet, and Nakuru counties. A total of 220 Oreochromis niloticus samples were captured from 11 liner ponds, eight earthen ponds, two concrete ponds, and one plastic tank from 22 farms in the three counties. External and internal organs were examined for parasite infestation. Skin scrapings and squash preparation of fish eyes were also examined to reveal the organisms through microscopic examination. A Pearson's correlation analysis between physicochemical parameters and parasitic prevalence was used to determine the strength and direction of correlation coefficients with significance at 95%. Overall parasitic prevalence infestation was 39.6% (87/220). Ten parasite genera were recovered, with Dactylogyrus species dominating overall at 15.9% (35/220), followed by Trichodina spp. (7.7%; 17/220). Epistylis species had the highest mean intensity of 12.8 AE 35.7 (total number of Epistylis parasites (141)/total of infested fish (11)). Earthen ponds had a significantly higher (36.2%, 29/80) prevalence of Dactylogyrus sp. than liner ponds (3.6%, 4/110) (p<0:001). Dissolved oxygen levels were 16.9 AE 0.7 mgL −1 in Bomet, 14.9 AE 0.3 mgL −1 in Kericho, and 12.5 AE 0.5 mgL −1 in Nakuru which were above desirable range for fish culture. The electrical conductivity in Bomet was 76 AE 5 µS/cm and Kericho 52 AE 4 µS/cm below the desirable range. Temperature, pH, phosphate, nitrates, and nitrites were within the desirable limit for fish farming. Electrical conductivity and pH had positive correlation of 1 and 0.97, respectively, with the prevalence of Acanthocephalus, Euclinostomum, and Trichodina species. Temperature and nitrate positively correlated between 0.80-0.89 and 0.90-0.99, respectively, with the prevalence of Dactylogyrus, Riboscyphidia, Epistylis, Camallanus, and Paracamallanus species. The study demonstrates that water quality significantly influences parasitic prevalence in aquaculture systems. Therefore, it is crucial for farmers to monitor water quality parameters to mitigate parasitic infestations.

Globally, parasitic infections hinder aquaculture productivity and sustainability. Improper water quality parameters reduce fish immunity, make them susceptible to parasites, and enhance parasitic proliferation in culture systems. Subsequently, this study aimed to determine the prevalence and intensity of ecto-and endo-parasite infesting Oreochromis niloticus in varying water quality in aquaculture systems in Kericho, Bomet, and Nakuru counties. A total of 220 Oreochromis niloticus samples were captured from 11 liner ponds, eight earthen ponds, two concrete ponds, and one plastic tank from 22 farms in the three counties. External and internal organs were examined for parasite infestation. Skin scrapings and squash preparation of fish eyes were also examined to reveal the organisms through microscopic examination. A Pearson's correlation analysis between physicochemical parameters and parasitic prevalence was used to determine the strength and direction of correlation coefficients with significance at 95%. Overall parasitic prevalence infestation was 39.6% (87/220). Ten parasite genera were recovered, with Dactylogyrus species dominating overall at 15.9% (35/220), followed by Trichodina spp. (7.7%; 17/220). Epistylis species had the highest mean intensity of 12.8 AE 35.7 (total number of Epistylis parasites (141)/total of infested fish (11)). Earthen ponds had a significantly higher (36.2%, 29/80) prevalence of Dactylogyrus sp. than liner ponds (3.6%, 4/110) (p<0:001). Dissolved oxygen levels were 16.9 AE 0.7 mgL −1 in Bomet, 14.9 AE 0.3 mgL −1 in Kericho, and 12.5 AE 0.5 mgL −1 in Nakuru which were above desirable range for fish culture. The electrical conductivity in Bomet was 76 AE 5 µS/cm and Kericho 52 AE 4 µS/cm below the desirable range. Temperature, pH, phosphate, nitrates, and nitrites were within the desirable limit for fish farming. Electrical conductivity and pH had positive correlation of 1 and 0.97, respectively, with the prevalence of Acanthocephalus, Euclinostomum, and Trichodina species. Temperature and nitrate positively correlated between 0.80-0.89 and 0.90-0.99, respectively, with the prevalence of Dactylogyrus, Riboscyphidia, Epistylis, Camallanus, and Paracamallanus species. The study demonstrates that water quality significantly influences parasitic prevalence in aquaculture systems. Therefore, it is crucial for farmers to monitor water quality parameters to mitigate parasitic infestations.

Globally, parasitic infections hinder aquaculture productivity and sustainability. Improper water quality parameters reduce fish immunity, make them susceptible to parasites, and enhance parasitic proliferation in culture systems. Subsequently, this study aimed to determine the prevalence and intensity of ecto-and endo-parasite infesting Oreochromis niloticus in varying water quality in aquaculture systems in Kericho, Bomet, and Nakuru counties. A total of 220 Oreochromis niloticus samples were captured from 11 liner ponds, eight earthen ponds, two concrete ponds, and one plastic tank from 22 farms in the three counties. External and internal organs were examined for parasite infestation. Skin scrapings and squash preparation of fish eyes were also examined to reveal the organisms through microscopic examination. A Pearson's correlation analysis between physicochemical parameters and parasitic prevalence was used to determine the strength and direction of correlation coefficients with significance at 95%. Overall parasitic prevalence infestation was 39.6% (87/220). Ten parasite genera were recovered, with Dactylogyrus species dominating overall at 15.9% (35/220), followed by Trichodina spp. (7.7%; 17/220). Epistylis species had the highest mean intensity of 12.8 AE 35.7 (total number of Epistylis parasites (141)/total of infested fish (11)). Earthen ponds had a significantly higher (36.2%, 29/80) prevalence of Dactylogyrus sp. than liner ponds (3.6%, 4/110) (p<0:001). Dissolved oxygen levels were 16.9 AE 0.7 mgL −1 in Bomet, 14.9 AE 0.3 mgL −1 in Kericho, and 12.5 AE 0.5 mgL −1 in Nakuru which were above desirable range for fish culture. The electrical conductivity in Bomet was 76 AE 5 µS/cm and Kericho 52 AE 4 µS/cm below the desirable range. Temperature, pH, phosphate, nitrates, and nitrites were within the desirable limit for fish farming. Electrical conductivity and pH had positive correlation of 1 and 0.97, respectively, with the prevalence of Acanthocephalus, Euclinostomum, and Trichodina species. Temperature and nitrate positively correlated between 0.80-0.89 and 0.90-0.99, respectively, with the prevalence of Dactylogyrus, Riboscyphidia, Epistylis, Camallanus, and Paracamallanus species. The study demonstrates that water quality significantly influences parasitic prevalence in aquaculture systems. Therefore, it is crucial for farmers to monitor water quality parameters to mitigate parasitic infestations.

Nile tilapia is the most preferred fish species for rearing and human consumption in Africa. Despite being a prolific breeder, demand for tilapia seeds remains high, and hatcheries have been established to meet this demand. However, hatcheries face significant challenges with high costs associated with feed, electricity, fish diseases and parasitism. A study was conducted in two hatcheries in Homa Bay County, Kenya in March and April 2023, in a bid to establish the prevalence and intensity of ectoparasites on various age groups of Nile tilapia (Oreochromis niloticus) in these facilities. One hundred and forty samples were collected from the two hatcheries and examined in-situ. These included 20 scoops each for eggs, fry and larvae and, 40 pieces each for brood stock and fingerlings. The eggs, larvae and fry were examined wholly under the microscope, while for fingerlings and brooders, skin scrapings, fin and gill clips were examined. Overall ectoparasite prevalence was 66% (92/140) and was highest in brooders (80%; 32/40) and lowest in larvae (10%; 2/20). Five genera were recovered, with the monogenean, Gyrodactylus being found in all age groups at a prevalence of 35% (49/140). Others included the monogenean, Dactylogyrus (12%; 17/140), ectopropozoans, Trichodina (11%; 16/140) and Epistylis (4%; (6/140) and the fish louse, Argulus spp. (0.7%; 1/140). The prevalence of Gyrodactylus spp. and Dactylogyrus spp. was statistically significant (X 2 =10, sig=0.039) and (X 2 =20, sig<0.001) in the hatcheries, respectively. The ciliate, Epistylis spp. had the highest mean intensity of 30.8 relative to other ectoparasites and there was a significant difference between the two farms (X 2 =4.4, sig=0.037). These findings indicate that ectoparasites are common in all age groups in hatcheries, and were most prevalent in brooders. Hatchery operators should implement strict biosecurity measures in order to avoid the spread of ectoparasites within the hatcheries and grower ponds.

Diplostomum species are the parasites responsible for diplostomiasis in fish which may cause ocular diseases such as blindness, eyefluke, severe ocular disease and opacity of the lens. The parasites use many organisms including fish as host. African catfish is one of the widely distributed fish species in tropical Africa and has become one of the most important culturable fish species in Africa especially in Nigeria. This study examined the occurrence of Diplostomum species in farm raised African catfish in Oyo state. The study was carried out in Oyo State, Nigeria. A total of 216 eye samples were collected from 108 fishes in 36 farms. The eye lens and vitreous were examined for the presence of Diplostomum species. The data obtained were analysed using descriptive statistics and regression analysis to the relationship between the eye size and parasite occurrence. The result shows that 16.20% of the samples had Diplostomum species. Males had higher occurrence (23.53%) than the female...

Francisella noatunensis subsp. orientalis (Fno) and Ichthyophthirius multifiliis (Ich) are deadly infectious pathogens in farmed tilapia, particularly during cold season when the water temperature drops to under 25 °C. We hypothesized that infection of the ectoparasite Ich might enhance susceptibility of hybrid red tilapia (Oreochromis sp.) to the facultative intracellular bacterium Fno. To prove the hypothesis, the experiment was designed as follows. Hybrid red tilapia naturally infected by Ich at 9 ± 6 theronts/fish gills and 4 ± 3 theronts/fish skin were distributed into 5 distinct groups exposed to different concentrations of Fno. In parallel, the same number of Ich-free tilapia were challenged to only Fno in the same manner. The results showed that cumulative mortality in the Fno single infection with 2.88 × 106 CFU mL−1 of water was 25 ± 7%, whereas 100% mortality was found in the coinfection treatment at dose of 1.93 × 105 CFU mL−1 of water. No mortality was observed in both control groups (Ich-infected and Ich-free fish). The coinfected fish revealed typical clinical signs and histopathological manifestations of francisellosis and ichthyophthiriasis. This study revealed synergistic effect of the Ich and Fno infection in hybrid red tilapia leading to the exacerbated mortality. Thus, farming management of fish to be free from the Ich ectoparasite might reduce risk of francisellosis and probably other bacterial diseases in farmed tilapia.

Piscine francisellosis, caused by the bacterium Francisella orientalis, poses a significant threat to various warm water fish. The coexistence of mosquito larvae, bacteria, and fish in aquatic ecosystems suggests the potential for interconnected pathogen/disease transmission. While mosquito larvae have been recognized as carriers of Francisella spp. in humans diseases, their role in transmitting francisellosis to aquatic animals remained unexplored. This study investigates whether mosquito larvae (Aedes aegypti) can uptake F. orientalis and transmit the disease to hybrid red tilapia (Oreochromis sp.). To assess uptake, naive mosquito larvae were exposed to F. orientalis-contaminated water or to experimentally infected tilapia, and specific PCR and culture techniques were employed to monitor F. orientalis. Rearing conditions at 25 • C and 30 • C were also examined to explore temperature influences. Results confirmed the presence of F. orientalis in larvae from both contaminated water and infected fish experiments. To assess their potential to transmit the disease, F. orientalis-exposed mosquito larvae were fed to naive tilapia. The challenged tilapia developed typical granulomas in the kidney and spleen after ingesting the F. orientalis-harboring mosquito larvae. Histopathological changes were more pronounced in fish kept at 25 • C than those at 30 • C. Corresponding with histopathology, all fish (n = 10) cultured at 25 • C were positive for F. orientalis-specific PCR assays, compared to 7 out of 10 samples at 30 • C. This study reveals, for the first time, that mosquito larvae can uptake F. orientalis and act as mechanical carriers for disease transmission in tilapia. Preventive measures such as mosquito control and water treatment might aid in eliminating larvae and contaminated bacteria, and reducing infection risks of piscine francisellosis. Additionally, this suggests that mosquito larvae could serve as a model for further studying the transmission of other aquatic animal diseases.

This study aimed to identify specific types of gastrointestinal helminthes and protozoa parasites that infect the Cyprinidae (Cyprinus carpio). During the growing period, 400 fish were randomly separated from five spawning fish ponds in Sulaimani province: Mara Rash (P1), Qalachwalan (P2), Kandashin (P3), Kalawanan (P4), and Piramagrun (P5). Fish infection with parasites was found to be 30.25% prevalent overall, with a high distribution rate of infestation in the P3 region of 48.75%. Diphyllobothrium latum, Ligula intestinalis, and Bothriocephalusacheilognathi were identified as the three helminthes species,with an overall prevalence rate of 22.75%, P3 had the highest examination rate of helminthes, with 9.25% of the Ligula intestinalis species, 7.5% of Diphyllobothrium latum, and 6% of Bothriecephalusopsariichthydis (acheilognathi) species. The t-test revealed the largest differences, at p-value (Two-tailed) < alpha 0.05, between the helminthes and protozoa parasites' prevalence and pond area. Three protozoa species have been identified, including Cryptosporidium spp., E. histolytica, and Eimeria spp.All spawning fish ponds had an overall prevalence rate of 7.75% of fish infested with protozoa; the greatest percentage was 2.75% for E. histolytica, followed by 2.5% for Eimeria spp., and 1.5% for Cryptosporidium spp. Based on the ponds, the most common protozoainfested fish were 5% of E. histolytica in P1, 3.75% of Cryptosporidium spp. in P3, and 3.75% of Eimeria spp. in P5. The investigation demonstrates that 1% of the mixed in various ponds were afflicted with protozoa parasites.

The research study is to control fish bacterial diseases or infections through application of bio control methods such as vaccines etc several methods have been tried to control fish diseases including the use of antibiotics but their haphazard use is associated with potentially negative effects as drug resistance and drug residues. The Clariidae is a freshwater fish family of the Siluroidei which apparently originated from Africa. The Clariidae are the African catfishes-so-called because of their whiskers resemble those of cats. Their geographical range currently extends to the Middle East and Southeast Asia. The genus Clarias occurs in both Africa and Asia. Listed 12 african genera with 74 species. The catfish are the preferred candidates for aquaculture in Nigeria accounting or over 60% of total aquaculture production of approx 88,000 metric tonnes. The advantages they bring to culture include their air-breathing capabilities which enables then to withstand oxygen-deficient conditions which characterize most culture conditions, generally hardy nature and resistance to diseases and fairly rapid growth-rate. As a result of these, they can be adapted for intensive production at densities of over 1000kg/m³. Market acceptability due to the large size, firm flesh and good taste add to the mix.The culture of catfishes currently is in the increase in Nigeria mainly due to the current availability of commercial feeds though at a high cost. I received funding from the International Foundation for Science (IFS) Based in Sweden for research into the pathogen problems militating against increase hatchery production of the various species of catfishes cultured in Nigeria and Africa as a whole. Our research disclose a range of important pathological conditions inimical to the culture of African Clariidae. In general single cell, direct life cycle pathogens more Innovations Innovations, Number 77 June 2024 1294 www.journal-innovations.com likely to cause harm to cultured fish on account of the high densities and the lack of need for an intermediate host or vector. In spite of myriad pathogens capable of infecting catfishes, here we shall concentrate on those capable of causing harm under culture conditions particularly intensive culture systems.

Bacterial infections can cause latent, low to high mortalities in aquaculture farms and wild fish while some bacteria may be zoonotic. This study isolated, characterized and identify potential pathogenic and zoonotic aerobic bacteria in farmed and wild Oreochromis jipe, O. niloticus, their hybrids and culture water source from Taita-Taveta County. One hundred and eleven apparently healthy-appearing fish consisting of 67 O. jipe, 34 O. niloticus and 10 hybrids and nine water (7 farms and 2 Lake Jipe) samples were processed. Samples were aseptically collected from each fish, namely, skin and kidney swabs; gills and intestinal tissues. Conventional culture, biochemical and Matrix Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry tests were done to identify isolated bacteria. A total of 596 bacterial isolates representing 22 genera were recovered from 444 fish organs and 9 water samples. Of these, the highest numbers were from the gills at 29.7% followed by skin 29.6%, intestines 24.4%, kidney 11.8% and the least from water at 4.7%. Potential fish pathogens were Bacillus cereus (8%), Aeromonas veronii (8%), Aeromonas hydrophila (5%), Lysinibacillus fusiformis (5%), Acinetobacter Johnsonii (4%) and Acinetobacter solii (4%). Potential pathogenic and zoonotic bacteria isolated were Staphylococcus lentus 17.9% (5/28), Aeromonas hydrophila 10.7% (3/28) and Aeromonas hormaechei 7.1% (2/28). From the sampling site; 28.4% (169/596) of the total isolates were collected from Taveta, then Mwatate with 26.9% (160/596), Mkwajuni 16.8%, (98/596), Kenya Wildlife Service 7.0% (42/596), Wundanyi 6.7% (40/596), Voi 6.6% (39/596) and the inlet of the Lake Jipe had a 3.2% (19/596) and from the water samples 4.7% (28/596). These findings confirm that fish in aquaculture farms, wild fish and water used for aquaculture harbors potentially pathogenic and zoonotic bacteria which may cause fish diseases and pose public health risks. Extension officers and farmers need awareness on mitigation measures against these pathogens.
Keywords: Aeromonas hydrophila, aquaculture, fish pathogens, prevalence, wild fish, Zoonosis

The aquaculture has surged in Kenya owing to dwindling wild stocks. However, this is coupled with challenges such as limited fish health knowledge and biosecurity measures. A cross sectional study was undertaken to determine risk factors and management practices associated with parasitic infestation of farmed Nile tilapia in Bomet and Kericho counties, Kenya. A total of 150 Nile tilapia (Oreochromis niloticus) were collected and subjected to standard parasitological examination. Potential risk factors associated with parasitic infestation in fish were assessed in 88 farms using pretested semi-structured questionnaires and on-site farm visit observations. Logistic regression analysis with the estimation of odds ratios (OR) was used to assess potential risks factors. Tilapia were dominant fish (>95%) and were farmed mainly in earthen ponds (> 61%). Most farmers (52.3%) used river water for ponds and 14% had experienced floods that introduced predators in the ponds. Farmers relied on fisheries department harvesting nets and only 12.5% sun dried the nets after use. Few farmers (37.5%) frequently cleaned and dried ponds before restocking, while 34.1% did not remove the pond bottom soil after fish harvesting. Approximately 3.4% of the farmers rated diseases as the main obstacle in fish farming and, 68.2% could not identify sick fish. Those who identified sick fish reported abnormal swimming (23.9%) and mortality (8%). Out of the 150 fish sampled, 62 (prevalence = 42%) were found to be infected with different genera of parasites including: Dactylogyrus spp. (21%); Epistylis spp. (7.3%); Riboscyphidia spp. (6.7%); Trichodina spp. (6%); Paracamallanus spp. (4.7%); Camallanus spp. (2%); Diplostomum spp. (2%) and Contracaecum spp. (1.3%). Dactylogyrus spp. were common in earthen ponds (91%) (p<0.001). Some management practices identified as possible risk factors for parasitic infestation in fish included; pond fertilization using livestock manure (OR=5.633), siting fish ponds in valleys/gullies (OR=2.028), use of river water for aqua farming (OR=1.654) and earthen pond types (OR=2.023). Farmers and extension workers should be trained on the importance of fish health and biosecurity. The authors recommend further detailed longitudinal controlled studies which consider myriad fish husbandry practices with parasitic infestations.
Keywords: Biosecurity, fish health, management practices, nile tilapia

The study aimed at determining the occurrence of pathogenic bacteria in fish and pond water, establishing respective antimicrobial susceptibility patterns and risk factors involved with their transmission small scale fish farms in Kirinyaga County. A questionnaire was administered to 92 fish farmers to collect data on farming practices, fish health and related problems. Pond physicochemical parameters were evaluated using standard procedures. Bacteria were isolated from: skin, gills, intestines, and kidney of 181 fish samples (88 tilapia, 53 catfish, 30 goldfish and 10 koi carp) and 27 pond water samples. Isolation and identification of the bacteria was carried out using conventional bacteriological protocols, while further characterization of some isolates was done using Analytic Profile index (API) 20E kit. Antibiotic and disinfectant susceptibility profiles of the some bacterial isolates were established using the disc diffusion and agar well diffusion technique respectively. Most ponds (68%) had plastic liner with monoculture tilapia. Most ponds were fertilized using livestock manure (48%). Most farmers (63%) shared fish nets with other farmers. Knowledge of farmers on basic fish health was poor (57%). Fish diseases were a challenge to 25% of the farms with incidences of fish mortality. The odds ratio (OR) for fish mortality and morbidity were highest in farms where ponds were fertilized using livestock manure (OR = 1.5). The mean±SD of physicochemical parameters were as follows: DO was 6.0±2.8 mg/L, temperature was 25.3±2.9°C, pH was 7.5±0.7, total ammonia was 0.72±1.9 mg/L, nitrate was 29.4±24.5 mg/L, nitrite was 0.27±0.6 mg/L and total phosphorous was 1.12±4.1mg/L. A total of 368 bacterial isolates were recovered from fish organs and water samples; they belonged to 17 genera with at least 18 different bacterial species. The predominant bacterial genera were; Aeromonas (18%), Proteus (15%), Pseudomonas (8%) and Enterobacter (5.7%), while 11% of the isolates could not be identified, with respect to the characterization procedures used. The bacterial isolates showed multiple resistant patterns to at least two antibiotics. Multiple antibiotic resistance index ranged from 0.04 to 0.25 with Streptococcus spp. having the highest score value. All the organisms were sensitive to gentamicin, while cotrimoxazole and ampicillin showed the highest resistance at 73% and 62% respectively. Most of the disinfectants showed antibacterial activity with varying magnitudes. The isolates were 100% sensitive to hydrogen peroxide and formalin at the recommended user-dilution. However, the isolates were resistant to sodium hypochlorite at recommended user-dilution. Farmed fish and their aquatic environments harbors potentially pathogenic and zoonotic bacteria which may cause great economic losses and public health scare, and therefore there is need to implement optimal management, biosafety and biosecurity programs. The results suggest that pond fertilization using livestock manure may be the main risk factor for fish mortality and morbidity The study has shown that some of the bacterial isolates were resistant to common antimicrobials, hence the necessity to ponder this resistance pattern for successful management of fish diseases.

Bacterial infections cause low to high mortality in fish, affecting the productivity of aquaculture. This study aimed at determining the occurrence of bacterial pathogens in farmed tilapia, catfish, goldfish and koi carp and source pond water in Kirinyaga County. A total of 181 healthy-appearing fish and 27 water samples from randomly selected fish farms in the county were processed. Bacteriological isolation was done on aseptically collected skin and kidney swabs; gills and a portion of intestines from each fish and water samples. Isolated bacteria were identified by colony morphology, Gram stain and biochemical characteristics, and some further characterized using API-20E kit. A total of 329 bacterial isolates were recovered from fish organs and 39 from pond water samples. They belonged to 17 genera with 18 different identified bacterial species. The most prevalent species found on the skin, gills, intestines, kidney, and water samples belonged to five genera: Proteus spp. (14.9%), Aeromonas hydrophila (8.2%), Aeromonas caviae (6.3%), Plesiomonas (5.2%), Flavobacterium spp. (5.2%), Aeromonas sobria (4.3%) and Micrococcus spp. (4.3%). Some isolates (11%, n=42) could not be identified. Bacterial species recovered from fish samples were also found in the water samples except: Streptococcus spp., Pseudomonas luteola, Serratia plymuthica and Klebsiella oxytoca. Raoultella terrigena was recovered from water samples only. The study has shown that farmed fish and aquatic environments harbor potentially pathogenic and zoonotic bacteria which may cause significant fish diseases and public health risks. Therefore, there is need to implement stringent management and biosecurity programs.

Canarium indicum offers the potential of usage in aquaculture. This study aimed to evaluate the utilization of C. indicum on growth performance, health, and resistance of Asian seabass Lates calcalifer challenged with Vibrio alginolyticus. The study employed a completely randomized design with seven treatments, namely positive control (K+), negative control (K-), vitamin control (KVit), antibiotic control (KAnt), doses of 5 g kg-1 (D05), 10 g kg-1 (D10), and 20 g kg-1 C. indicum (D20). The test feed was prepared with a coating method and fed for 30 days. On the 31st day of rearing, a challenge test was conducted by injecting V. alginolyticus intramuscularly at 10 6 CFU mL-1. The results showed that C. indicum treatment for 30 days had a significantly different effect (P<0.05) on weight gain and average daily growth, while KVit and KAnt treatments were not different from the control. After the challenge test, all doses of C. indicum treatment, as well as KVit and KAnt treatments, showed survival significantly different (P<0.05) from that of the positive control, which ranged from 88.89% to 95.56% and was not significantly different (P>0.05) from the negative control. The survival rate condition is identical to the cumulative survival condition which shows the highest mortality found in the positive control. The administration of C. indicum at a dose of 5 g kg-1 to 20 g kg-1 improved the growth performance and prevented V. alginolyticus infection.

In the current study, 308 Oreochromis niloticus and 76 Barbus species were subjected to standard postmortem and parasitological examinations. Of them, 30.9% of fish harbored at least one or more helminth parasites in their kidney, pericardial and brachial cavity. Parasite genera identified were Contracaecum (18.5%) Clinostomum (6.5%) and Euclinostomum (3.9%). The overall prevalence in O. niloticus was 38.6% but no parasite was identified in Barbus species. Despite higher prevalence was recorded in O. niloticus collected from Seka-Chekorsa pond (57.1%) and the least from Furustale ponds (30.9%), there was no statistical significance variation (P>0.05) among fishes collected from different ponds and Gilgel-Gibe River. Statistically significant differences were recorded among the different age groups of O. niloticus (χ2 = 12.1, Df= 3; P<0.05), with high prevalence in fingerlings (55.5%) and juvenile (53.1%) as compared to young (36.5%) and adult fish (29.4%). In conclusion, fish parasitism constitutes a huge health threat to O. niloticus. Lastly, the current study revealed that Barbus species showed some resistance for parasitic helminthes at least identified in this study. Therefore, detailed study in Barbus immunity against the mentioned helminthes and awareness creation on the overall fish management is recommended.

In the current study, 308 Oreochromis niloticus and 76 Barbus species were subjected to standard postmortem and parasitological examinations. Of them, 30.9% of fish harbored at least one or more helminth parasites in their kidney, pericardial and brachial cavity. Parasite genera identified were Contracaecum (18.5%) Clinostomum (6.5%) and Euclinostomum (3.9%). The overall prevalence in O. niloticus was 38.6% but no parasite was identified in Barbus species. Despite higher prevalence was recorded in O. niloticus collected from Seka-Chekorsa pond (57.1%) and the least from Furustale ponds (30.9%), there was no statistical significance variation (P&gt;0.05) among fishes collected from different ponds and Gilgel-Gibe River. Statistically significant differences were recorded among the different age groups of O. niloticus (χ2 = 12.1, Df= 3; P&lt;0.05), with high prevalence in fingerlings (55.5%) and juvenile (53.1%) as compared to young (36.5%) and adult fish (29.4%). In conclusion, fish ...

The goal of this study was to assess common endoparasites on Tilapia zillii in the Tono Reservoir, as well as to investigate the mean intensity and prevalence of these parasites. A total of 175 fish specimens were examined during the study. Endoparasites of three metazoans and one protozoan were observed from the Tilapia zillii gills, intestines, and stomach. The findings showed that the most common endoparasites affecting Tilapia zillii are Ichthyopthirius multifiliis, Bothriocephalus sp., Contracaecum sp., and Dactylogyrus sp. Also, Contracaecum sp had the highest prevalence of 29.71, followed by Bothriocephalus sp (18.86), Ichthyopthirius multifiliis (12), and Dactylogyrus sp (6.86). The average quantity of Bothriocephalus sp was 0.84, Contracaecum sp was 1.33, Dactylogyrus sp was 0.31, and Ichthyopthirius multifiliis was 0.54. The reservoir's physicochemical parameters changed every month due to inflows and other runoffs joining. Low levels of these parameters were discovered to influence the prevalence and distribution of these parasites. Haematological parameters showed significant changes between the adult and fingerling groups, where it was observed an improvement in health status in the adult group. It was also observed that fingerlings (0.1-20 g) were more infected, which significantly affected their blood profile.

The aquaculture has surged in Kenya owing to dwindling wild stocks. However, this is coupled with challenges such as limited fish health knowledge and biosecurity measures. A cross sectional study was undertaken to determine risk factors and management practices associated with parasitic infestation of farmed Nile tilapia in Bomet and Kericho counties, Kenya. A total of 150 Nile tilapia (Oreochromis niloticus) were collected and subjected to standard parasitological examination. Potential risk factors associated with parasitic infestation in fish were assessed in 88 farms using pretested semi-structured questionnaires and on-site farm visit observations. Logistic regression analysis with the estimation of odds ratios (OR) was used to assess potential risks factors. Tilapia were dominant fish (>95%) and were farmed mainly in earthen ponds (> 61%). Most farmers (52.3%) used river water for ponds and 14% had experienced floods that introduced predators in the ponds. Farmers relied on fisheries department harvesting nets and only 12.5% sun dried the nets after use. Few farmers (37.5%) frequently cleaned and dried ponds before restocking, while 34.1% did not remove the pond bottom soil after fish harvesting. Approximately 3.4% of the farmers rated diseases as the main obstacle in fish farming and, 68.2% could not identify sick fish. Those who identified sick fish reported abnormal swimming (23.9%) and mortality (8%). Out of the 150 fish sampled, 62 (prevalence = 42%) were found to be infected with different genera of parasites including: Dactylogyrus spp. (21%); Epistylis spp. (7.3%); Riboscyphidia spp. (6.7%); Trichodina spp. (6%); Paracamallanus spp. (4.7%); Camallanus spp. (2%); Diplostomum spp. (2%) and Contracaecum spp. (1.3%). Dactylogyrus spp. were common in earthen ponds (91%) (p<0.001). Some management practices identified as possible risk factors for parasitic infestation in fish included; pond fertilization using livestock manure (OR=5.633), siting fish ponds in valleys/gullies (OR=2.028), use of river water for aqua farming (OR=1.654) and earthen pond types (OR=2.023). Farmers and extension workers should be trained on the importance of fish health and biosecurity. The authors recommend further detailed longitudinal controlled studies which consider myriad fish husbandry practices with parasitic infestations.

Sampling was carried out at the Experimental Fish Culture Station of the Higher Institute of Technology Education (ISET), which is located on the banks of the Senegal River in the town of Rosso in the Trarza wilaya of southern Mauritania. It is located between latitude 16° 34'18.038 '' N and longitude 15° 48'36.906 'W (Figure 1). Are climate being desert. The average temperature is 27.7 °C. The average annual rainfall is 224mm. Material and Methods The present study involved 1000 tilapia fish including 141 infested with Lernaea cyprinacea Linnaeus, 1758. In ISET lakes, Tilapia fish are caught line by hooks using wet

Salah satu kendala dalam budidaya perikanan laut adalah terjadinya kematian ikan akibat serangan penyakit. Suatu penelitian dengan tujuan untuk mengetahui efektivitas kombinasi vaksin bakteri polivalen dengan vaksin anti “grouper sleepy disease iridovirus” (GSDIV) telah dilakukan di Balai Besar Penelitian dan Pengembangan Budidaya Laut Gondol, Bali. Vaksin bakteri polivalen terdiri dari tiga bakteri patogen yang sudah diinaktivasi, yaitu Vibrio harveyi, V. alginolyticus, dan Photobacterium leiognathi. Vaksin bakteri polivalen diaplikasikan melalui cara perendaman, sedangkan vaksin anti GSDIV diaplikasikan melalui penyuntikan intra-peritoneal pada benih kerapu macan (Epinephelus fuscoguttatus). Selama tiga bulan penelitian ikan dipelihara dengan sistem air mengalir dalam bak beton volume 2 m3 yang dilengkapi dengan sistem penyaringan air dan aerasi. Ikan percobaan diberi pakan pellet dua kali sehari, pagi dan sore. Pengamatan di lakukan terhadap nilai titer antibodi dan sintasan selama tiga bulan pemeliharaan. Hasil penelitian menunjukkan bahwa nilai titer antibodi kelompok ikan yang divaksinasi meningkat secara signifikan seiring dengan lamanya waktu pemeliharaan. Nilai titer antibodi tertinggi diberikan oleh perlakuan penyuntikan vaksin anti GSDIV secara tunggal (128) diikuti oleh perlakuan perendaman dalam vaksin bakteri polivalen (32-64) dan kombinasi vaksin bakteri polivalen dengan vaksin anti GSDIV (32-64). Sintasan ikan dari kelompok perlakuan vaksinasi juga berbeda secara nyata dibanding kelompok kontrol, baik sintasan selama tiga bulan pemeliharaan maupun setelah uji tantang. Nilai “Relative Percent Survival” (RPS) setelah uji tantang berkisar dari 65% sampai 84%. Hasil penelitian ini menunjukkan bahwa vaksin efektif meningkatkan imunitas ikan kerapu macan terhadap infeksi bakteri dan virus.

Budidaya ikan penting karena saat ini perikanan tangkap mengalami overfishing sehingga produksi budidaya mengalami peningkatan. Hambatan yang dialami oleh budidaya saat ini yaitu kematian yang disebabkan oleh infeksi mikroorganisme yang memberi dampak negatif di bidang budidaya ikan. Infeksi mikroorganisme menyebabkan timbulnya penyakit pada biota yang dibudidayakan. Salah satu jenis virus yang dikenal dapat menyebabkan tingkat kematian tinggi pada biota laut yang dibudidayakan adalah iridovirus. Virus ini mampu menginfeksi ikan mulai dari ukuran benih sampai dnegan konsumsi dengan tingkat kematian hampir 100%.Vaksinasi menjadi salah satu solusi dalam pencegahan penyakit inveksi untuk mengurangi tingkat kematian ikan laut. Adanya perkembangan mengenai vaksin saat ini vaksin tidak hanya dilakukan dengan mono spesies namun bisa kombinasi dengan mikroorganisme lain untuk menciptakan sistem imun yang lebih spesifik, dalam mengatasi iridovirus penggunaan vaksin kombinasi mampun meningkatkan nilai RPS tertinggi daripada vaksin lainnya dengan nilai sekitar 7,27%-84,61%, hal ini terbukti bahwa adanya perkembangan vaksin dapat membantu mengatasi permasalahan penyakit pada biota laut akibat infeksi virus.

Streptococcosis merupakan penyakit pada ikan nila yang di sebabkan Streptococcus agalactiae. Penelitian ini untuk bertujuan untuk mengetahui efektivitas vaksin Streptococcus agalactiae dalam mencegah penyakit Streptococcus pada ikan nila. Dengan cara perendaman tubuh ikan dan injeksi intraperitoneal,dengan konsentrasi 107 sel/mL 106 sel/mL 104 sel/mL dan kontrol. Ikan kontrol biasanya disuntik dengan BHIB (Brain Heart infusion Broth). Ikan percobaan di tantang dengan injeksi intraperitoneal pada dosis 103 cfu/mL Streptococcus agalactiae.

Budidaya ikan kerapu masan (epinephlus fuscogattatus) merupakan salah satu sektor penting dalam industri perikanan.Nmaun, salah satu tantangan besar dalam budidaya ikan adalah resiko infeksi bakteri yang dapat menyebabkan kerugian besar.dalam konteks ini,pengembangan teknologi vajsinasi menjadi sangat penting untuk meningkatkan keberhasilan budidaya ikan.Artikel ini membahas tentang aplikasi vaksin bakteri polivalen pada ikan kerapu macan yang bertahan dipelihara di keramba jaring apung,dengan tujuanuntuk meningkatkan ketahanan imun ikan terhadap infeksi bakteri.

Uji lapang vaksin Streptococcus dilakukan untuk mengetahui seberapa efektif vaksin itu dan bagaimana ikan nila (Oreochromis niloticus) yang kebal terhadap rangsangan yang diberikan. Keramba jaring apung (KJA) adalah subjek penelitian. Jenis vaksin yang digunakan adalah vaksin S1N8 dan GM2.4 yang diinaktivasi dengan formalin 0,3%. Vaksin awal, atau priming, diberikan melalui rendaman, dan vaksin ulang diberikan melalui suntikan. Untuk 1.000 ikan, 10 mL vaksin/100 L air direndam selama 15 menit. Booster diberikan dengan suntikan 0,2 mL/ikan. Hasil menunjukkan bahwa untuk vaksin S1N8, kombinasi pemberian vaksin priming melalui rendaman dan booster dengan suntikan menghasilkan sintasan paling tinggi (70,3% hingga 72,5%), dibandingkan dengan vaksin GM2.4 (59,3% hingga 62,5%), dan kontrol (35,5% hingga 42,0%

Studi ini membandingkan pengembangan metode vaksinasi oral menggunakan ragi rekombinan untuk ikan kerapu convict dari dua sumber yang berbeda. Dari sumber pertama, penelitian yang dilakukan oleh Cho et al. (2017) menunjukkan bahwa vaksinasi oral memberikan keuntungan praktis yang signifikan dibandingkan dengan metode konvensional yang memerlukan penanganan individual pada setiap ikan. Mereka menekankan bahwa vaksinasi oral menggunakan ragi rekombinan merupakan pendekatan yang menjanjikan dalam meningkatkan kesehatan dan kesejahteraan ikan kerapu convict. Sementara itu, dari sumber kedua, studi ini memberikan kontribusi penting dalam pengembangan teknologi vaksinasi oral untuk ikan, khususnya dalam konteks perlindungan terhadap infeksi RGNNV pada ikan kerapu convict. Vaksinasi oral ini dianggap sebagai solusi yang ramah lingkungan dan efisien dalam pencegahan penyakit pada populasi ikan budidaya. Dengan hasil yang menjanjikan, vaksinasi oral ini diharapkan dapat menjadi solusi yang efektif dalam upaya pencegahan penyakit pada industri budidaya ikan. Melalui studi banding ini, terlihat bahwa pengembangan vaksinasi oral menggunakan ragi rekombinan memiliki potensi besar dalam meningkatkan kesehatan ikan budidaya, serta membuka peluang untuk pengembangan metode vaksinasi oral serupa untuk spesies ikan lainnya. Dengan terus dilakukannya penelitian dan pengembangan lebih lanjut, teknologi vaksinasi oral ini diharapkan dapat menjadi salah satu solusi efektif dalam upaya pencegahan penyakit pada industri budidaya ikan.

k
Riset dengan tujuan untuk mengetahui efektivitas (yield-gap) aplikasi
vaksin Streptococcus agalactiae (pure whole cell) untuk pencegahan penyakit
streptococcosis pada budidaya ikan nila (Oreochromis niloticus) telah dilakukan
pada skala lapang. Isolat bakteri S. agalactiae N14G digunakan sebagai sumber
antigen dalam pembuatan vaksin. Vaksinasi awal (priming) diberikan melalui
perendaman, dan dua bulan kemudian dilakukan vaksinasi ulang (booster) melalui
pakan. Pada hari ke-14 pasca vaksinasi ulang, dilakukan uji tantang pada dosis
lethal (LD50) terhadap bakteri aktif, dan diamati selama 14 hari pasca infeksi
buatan. Hasil penelitian menunjukkan bahwa pemberian vaksin S. agalactiae (pure
whole cell), vaksin Streptovac (kombinasi S. agalactiae dan A. hydrophila) dan
kontrol memberikan nilai sintasan dan RPS masing-masing sebesar 52,08% dan
10,01%; 65,58% dan 35,36%; dan 46,75% (sintasan). Hasil uji tantang terhadap
bakteri S. Agalactiae aktif diperoleh nilai sintasan dan RPS pada kelompok ikan
yang diberi vaksin S. agalactiae sebesar 50,00% dan 37,50%; vaksin Streptovac
sebesar 40,00% dan 25,00%; sedangkan nilai sintasan pada kelompok kontrol
sebesar 20,00% sehingga pemberian vaksin lebih baik dibandingkan tidak divaksin.

Timbulnya serangan penyakit adalah hasil interaksi yang tidak sesuai antara inang (host), organisme penyebab penyakit (pathogen) dan kondisi lingkungan. Interaksi yang tidak sesuai itu dapat menyebabkan stress pada ikan, nafsu makan menurun, yang selanjutnya menyebabkan mekanisme pertahanan tubuh tidak bekerja secara optimal, akhirnya infeksi penyakit mudah masuk. Streptococcus adalah bakteri spheris gram positif-coccus termasuk dalam family Streptococcaceae dengan karateristik bulat/oval, tidak bergerak, sifat pertumbuhan koloni dan memanjang seperti rantai, diameter koloni berukuran 0,7 – 1,4 µm. Metode review yang digunakan adalah metode summarize yaitu metode review jurnal dengan meringkas dan menulis kembali sumbernya melalui proses pengambilan kesimpulan dari sebuah teks hanya dengan mengambil bagian-bagian pentingnya saja. Review yang dilakukan untuk mengkaji dan mengambil kesimpulan tentang pencegahan penyakit berupa penggunaan berbagai jenis vaksin yang telah dikembangkan untuk infeksi bakteri Streptoccous. Dengan mengetahui gejala klinis dari penyakit infeksi tersebut, kita dapat melakukan pencegahan penyakit. Salah satu upaya pencegahan penyakit dilakukan yaitu dengan vaksin. Vaksin merupakan suatu zat yang dimasukkan kedalam tubuh yang untuk mendapatkan kekebalan tubuh (antibody) terhadap suatu penyakit infeksi tertentu. Terdapat berbagai cara pemberian vaksin yang diberikan kepada ikan termasuk metode perendaman, oral melalui pakan, dan injeksi.  Sampai saat ini sudah banyak vaksin yang dibuat dan dikembangkan sebagai upaya pencegahan penyakit infeksi bakteri Streptoccus serta meningkatan sintasan ikan budidaya diatas 70%. Sehingga kematian ikan akibat bakteri Streptoccous dapat dicegah dan tidak menimbulkan kerugian finansial.

Kata Kunci : Penyakit, Streptococcus, Vaksin, Pencegahan penyakit

The Diplostomum parasite completes its life-cycle in fish eating birds, but spends considerable time in the eye vitreous humor of many fresh water fishes. Its infection in fish causes severe ocular pathology, and leads to increased susceptibility to predation. A study on Diplostomum parasites was conducted at Chepkoilel University with an objective of assessing its parasitic indices and effects on O. niloticus. A total of 40 fish were collected from the fish farm and 155 from the dams between November 2010 and January, 2011. Fish were weighed and length measured to ascertain their condition factor. The fish were observed for the Diplostomum parasite to ascertain parasitic indices in the different habitats. The parasite abundance was related to fish size and condition factor to determine parasite’s effect on O. niloticus. Fish were found to have a parasitic prevalence (%) of 100, 84 and 66 in Kerita dam, Kesses dam and Chepkoilel fish farm. Parasite mean intensity was 12, 9 and 14 re...

Ikan nila Jatimbulan memiliki potensi dikembangkan di Indonesia karena mudah dilakukan budidaya. Penggunaan anestetik pada proses transportasi kering dan pemeriksaan medis pada ikan banyak menggunakan minyak cengkeh karena murah dan mudah didapatkan. Penelitian ini dilakukan untuk mengetahui efek penggunaan minyak cengkeh sebagai anestetik pada gelembung renang dan laju denyut jantung. Ikan nila Jatimbulan dewasa, umur 4 bulan, jantan sebanyak 35 ekor dibagi dalam 7 kelompok perlakuan yaitu kontrol (P1), induksi anestesi minyak cengkeh dosis 20 ppm (P2), 30 ppm (P3), 40 ppm (P4), 50 ppm (P5), 60 ppm (P6) dan 70 ppm (P7). Metode pengukuran gelombung renang menggunakan pencitraan radiografi proyeksi lateral dan ekhokardiografi untuk pengukuran laju denyut jantung. Hasil uji Tukey menunjukkan tidak ada perbedaan rata-rata panjang gelembung renang setiap kelompok, sedangkan dosis P5 (50 ppm) dan P6 (60 ppm) menyebabkan peningkatan lebar gelembung renang dibandingkan P1 (kontrol) dan P2 ...