Administration of live-attenuated vaccine of Vibrio harveyi to improve survival of gnotobiotic brine shrimp (Artemia salina) model against multipleVibrio infection

Newly developed live-attenuated protease derivative from pathogenic Vibrio harveyis train Vh1 as a live vaccine to against Vibriosis of aquatic animals. In the current study, we used the gnotobiotic A. salina as model to evaluate the safety and efficacy of the live-attenuated. This study was conducted by bacterial safety experiment and bacterial efficacy experiment. During the bacterial safety, the wild type and live-attenuated of V. harveyi (MVh-vhs) were tested for 48 hours on the Artemia larvae (instar II). During the efficacy experiment, the A. salina larvae were incubated with different concentration of live-attenuated V. harveyi (MVh-vhs), then challenged with V. harveyi, V. alginolyticus and V. parahaemolyticus. The result of safety experiment showed that the high concentration of live-attenuated mutant V. harveyi (MVh-vhs) at concentration of 109 CFU/mL is safe and had improved the A. salina larvae survival compared to other groups. On the other hand, pathogenic wildtype V. harveyi caused lethal effect on A. salina larvae by decreasing their survival. The surprising result of efficacy experiment showed that 107 CFU/mL of live attenuated MVh-vhs with 6 hours post incubation withA. salina larvae contributed higher survival while 109 CFU/mL of live attenuated MVh-vhs with 24 hours incubated A. salina larvae contributed higher survival against multiple Vibrio challenge. In this study, we concluded that the incubation time had affect bacterial concentration uptake by A. salina larvae and affect the effectiveness of Artemia bioencapsulation for targeted hosts

Exploring the internationalization strategy of higher education institutions and halal food ecosystem in Malaysia

Internationalization of higher education has become a strategic agenda of the development in Malaysia. In the age of globalization, the higher education sector experiences rapid growth with the increasing number of international students choosing Malaysia as a destination in pursuing their tertiary education. One of the crucial roles for Malaysian Higher Education Institutions (HEIs) is to successfully transform Malaysia to be the international hub for higher education. Globalization has changed the landscape of development in the higher education sector. Exploring the expectations, demands and preferences of international students is crucial in crafting the most suitable approach to enhance the internationalization strategy. As a multi-ethnic society with a majority Muslim population, Malaysian HEIs have the advantage to attract more international students through providing a ‘Muslim-friendly' Halal ecosystem. A dearth in HEIs internationalization literature discussing on Halal food ecosystem indicates the urgency to discover the potential of Halal ecosystem in accelerating the HEIs internationalization strategy. Hence, this paper seeks to explore the experiences of international students on Halal food ecosystem in Malaysia. A qualitative methodology using phenomenology approach was used to gather the research data from informants studied in public universities in Klang Valley area. The preliminary findings indicated that the Halal food ecosystem has a positive contribution to the HEIs internationalization strategy

Environmental factors associated with the presence of vibrionaceae in tropical cage-cultured marine fishes

This study investigated the environmental factors associated with the presence of Vibrionaceae in economically important cage-cultured tropical marine fishes: the Asian Seabass Lates calcarifer, snapper Lutjanus sp., and hybrid grouper Epinephelus sp. Fish sampling was conducted at monthly intervals between December 2016 and August 2017. The body weight and length of individual fish were measured, and the skin, eye, liver, and kidney were sampled for bacterial isolation and identification. Water physicochemical parameters during the sampling activities were determined, and the enumeration of total Vibrionaceae count was also conducted from water and sediment samples. Nine species of Vibrio were identified, including V. alginolyticus, V. diabolicus, V. harveyi, V. campbellii, V. parahaemolyticus, V. rotiferianus, V. furnissii, V. fluvialis, and V. vulnificus. Photobacterium damselae subsp. damselae was also identified. A total of 73% of the isolated Vibrio belonged to the Harveyi clade, followed by the Vulnificus clade (5.5%) and Cholera clade (0.6%). Highest occurrence of Vibrio spp. and P. damselae subsp. damselae was found in hybrid grouper (72%), followed by Asian Seabass (48%) and snapper (36%). The associations of Vibrio spp. and P. damselae subsp. damselae with the host fish were not species specific. However, fish mortality and fish size showed strong associations with the presence of some Vibrio spp. On average, 60% of the infected cultured fish exhibited at least one clinical sign. Nevertheless, inconsistent associations were observed between the pathogens and water quality. The yearlong occurrence and abundance of Vibrionaceae in the environmental components indicate that they might serve as reservoirs of these pathogens

Effects of skin abrasion in immersion challenge with Vibrio harveyi in Asian seabass Lates calcarifer fingerlings

Skin abrasions often occur in farmed fish following handling by labourers, injury by farm facilities, cannibalism and ectoparasites. Vibrio spp. are opportunistic pathogens that can invade host fish through damaged tissues and cause outbreaks of vibriosis. This study describes the effect of skin abrasions on the infectivity of V. harveyi using Asian seabass Lates calcarifer (Bloch, 1790) fingerlings as a case example and compares bacterial load and fish survival following immersion challenge with different doses. In total, 315 fish (6.67 ± 1.8 g) were divided into 3 treatments: skin abrasion followed by immersion infection, immersion infection only and an uninfected, uninjured control. Fish in the infection treatments were divided into 3 subgroups and exposed in triplicate to a 7 d immersion challenge with 106, 107 and 108 CFU ml−1 of live V. harveyi. No mortalities were observed in the control and immersion infection groups. However, fish in the skin abrasion treatment group that were infected with 108 CFU ml−1 of live V. harveyi showed signs of progressing disease throughout the experiment, which resulted in mortalities. Significantly higher bacterial loads (p < 0.05) were recorded in the intestine, liver and gills of the fish in this group. Fish in the skin abrasion treatment that were exposed to 107 and 108 CFU ml−1 of V. harveyi showed 100% mortality by Days 5 and 4, respectively. These findings confirm that skin injuries increase the susceptibility of seabass fingerlings to V. harveyi infection

Vibriosis in cultured marine fishes: a review

For more than a century, vibriosis affects various species of economically important cultured marine fishes around the globe. The knowledge of this bacterial disease on many species of cultured fish is still lacking, but progressing. This review focuses on updated fundamental knowledge related to vibriosis including the history, taxonomy, and various epidemiological aspects such as socio-economy, clinical signs, pathological changes, diagnosis, pathogenesis, transmission, risk factors and control measures of vibriosis. This review revealed a rising prevalence of vibriosis in aquaculture, concomitant with the rapid development of this industry worldwide. Yet, information on Vibrio infection in cultured fish, particularly on the Vibrio of non-medical importance, the influence of their virulence toxins to host cells, effects of global warming and the socio-economic impacts are still scarce, and need more profound studies. Moreover, comprehensive epidemiological information on vibriosis are quite limited in many Asian countries with tropical climate, limiting the progression in control and prevention aspects of the disease

Vibriosis in cultured marine fishes: a review

For more than a century, vibriosis affects various species of economically important cultured marine fishes around the globe. The knowledge of this bacterial disease on many species of cultured fish is still lacking, but progressing. This review focuses on updated fundamental knowledge related to vibriosis including the history, taxonomy, and various epidemiological aspects such as socio-economy, clinical signs, pathological changes, diagnosis, pathogenesis, transmission, risk factors and control measures of vibriosis. This review revealed a rising prevalence of vibriosis in aquaculture, concomitant with the rapid development of this industry worldwide. Yet, information on Vibrio infection in cultured fish, particularly on the Vibrio of non-medical importance, the influence of their virulence toxins to host cells, effects of global warming and the socio-economic impacts are still scarce, and need more profound studies. Moreover, comprehensive epidemiological information on vibriosis are quite limited in many Asian countries with tropical climate, limiting the progression in control and prevention aspects of the disease

Recent update on the prevalence of Vibrio species among cultured grouper in Peninsular Malaysia

Vibrio infections are common among marine fish and lead to serious problems in the aquaculture sector. This study reports a recent occurrence of Vibrio species (spp.) isolated from cultured groupers in Peninsular Malaysia using the gyrB and pyrH genes. A total of 147 Vibrio strains were successfully isolated from 77 (64%) groupers using culture method and subjected to gyrB and pyrH sequencing for species identification and confirmation. Results showed that 89% of Vibrio strains were identified and clustered to six groups of Vibrio spp., while 11% were not clustered to any Vibrio spp. using the gyrB sequences. Meanwhile, by analysis of the pyrH sequences all the 147 Vibrio strains (100%) were successfully identified and clustered into 11 groups of Vibrio spp., including the gyrB non‐identified strains. The pyrH gene provides a better resolution for identification of Vibrio spp. compared with the gyrB gene. Thus, the pyrH gene was more suitable for a rapid determination of Vibrio spp. distribution in Peninsular Malaysia. Using the pyrH gene, our study found higher prevalence of Vibrio vulnificus (33%), V. alginolyticus (24%) and V. parahaemolyticus (22%), followed by V. rotiferianus (5%), V. harveyi (3%), V. tubiashii (2%), V. campbellii (2%), V. ponticus (1%), V. diabolicus (1%), V. owensii (1%) and others Vibrio sp. (7%). Thus, the results of this study revealed that the occurrence of pathogenic vibrios among grouper fish is still high in Malaysian aquaculture. In addition, the pyrH gene was proved as a suitable marker for rapid identification of Vibrio species compared with the gyrB gene

Efficacy of bath vaccination with a live attenuated Vibrio harveyi against vibriosis in Asian seabass fingerling, Lates calcariferaq

INA SALWANY BINTI MD YASIN/// MOHD ZAMRI BIN SAAD,ANNAS BIN SALLEH,ZARIRAH BINTI MOHAMED ZULPERI/// Aslizah Mohd Aris,Nurhidayu Al‐saari,Yong Kit Chin,Santha Silvaraj,JingYie Lee,Aslah Mohama

The genome sequence of Vibrio parahaemolyticus C5A causing acute hepatopancreatic necrosis disease in shrimps isolated from a Malaysia shrimp culture pond

We report the complete genome sequence of Vibrio parahaemolyticus strain C5A causing an acute hepatopancreatic necrosis disease (AHPND) in Penaeus vannamei sampled from a culture pond in the east of peninsular Malaysia isolated in 2017

Selection of potential bacterial probiotics for tiger grouper (Epinephelus fuscoguttatus forsskal) larviculture

Rapid development in today’s aquaculture industries have expanded to the level of commercial scale and has indirectly led to environmental degradation and catastrophic losses due to bacterial diseases. Thus, the application of probiotics was proposed as an environmental-friendly preventive measure. This study was carried out specifically to search for probiotic candidates for use in the larviculture of Epinephelus fuscoguttatus. Hypothetically, selected intestinal microfloras of E. fuscoguttatus are able to confer protection on larvae by exhibiting antagonistic activity against pathogenic bacteria. A set of criteria for bacterial probiotics was used in this study, focusing on phenotypic and genotypic characterizations of the candidate strains, in vitro capacity to inhibit the growth of targeted competitive strains, the haemolytic activity and antibiotic susceptibility of selected candidates and virulence assessment to the host. Initially, the intestines of healthy individual grouper which were randomly collected from three geographically distant farms in Malaysia were processed and bacterial isolation was performed. A preliminary identification and grouping method successfully identified 31 species, while 22 isolates as unidentified from a total of 123 isolated aerobes and facultative anaerobes. The first screening process was undertaken to assess the antagonistic activity exhibited by the isolates against four common fish pathogens. Of the 123 isolates, 40 (32.5%) displayed strong antagonistic activity, mostly Gram-positive bacteria (n=32; 80%). The haemolytic nature of the short listed probionts was then assessed where only nine (22.5%) showed no breakdown of red blood cells and they were grouped into five genera based on 16S rRNA gene sequence analysis. This genotypic strategy was used to eliminate another four isolates considering their potential pathogenic nature to human and sequences similarity from which they were considered identical. Screening process was ended with the antibiotic susceptibility assay of five selected isolates which resulted in the elimination of V. harveyi i.e. JAQ01 and JAQ02 due to their opportunistic nature and the availability of incomprehensible evidence that these strains maympotentially carry resistance genes for β-lactamase in a transferrable genetic material.Considering the needs for an advanced study to measure the antagonism capacity of three selected candidates, bacteriocin-like inhibitory substances (BLIS) and co-culture assays were performed. The former assay nominated Bacillus cereus JAQ04 as the most promising candidates with initial addition at 108 and/or 109 cfu/mL with 48 and/or 72 h pre-incubation time. Alternatively, for co-culture method, the growth of pathogenic V. alginolyticus can also be inhibited at 105 cfu/mL of all probionts tested. Both methods revealed that the highest inhibition of pathogens has always associated with the introduction of significantly higher densities of probionts. Lastly, virulence assessment was made by determining the relationship observed between the probiont concentrations with larval survival. Conclusively, in relation to the previous antagonistic assay, 105 cfu/mL of B. cereus (JAQ04) and Micrococcus luteus (JAQ07) were recommended as the safest and adequate initial amount for use in field trial. Both bacteria needed at least 48 h to proliferate before being able to counteract the pathogens. Thorough studies on these bacteria including in-depth assessment on their effect in vivo are recommended