Development and efficacy of feed-based recombinant vaccine encoding the cell wall surface anchor family protein of Streptococcus agalactiae against streptococcosis in Oreochromis sp.

This study was carried out to determine the antibody responses and protective capacity of an inactivated recombinant vaccine expressing the cell wall surface anchor family protein of Streptococcus agalactiae following oral vaccination against streptococcosis in tilapia. Tilapia were vaccinated orally with 106 CFU/mL of the recombinant vaccine incorporated in feed (feed-based recombinant vaccine) (vaccinated group or Group 1), 106 CFU/mL of pET-32 Ek/LIC vector without cell wall surface anchor family protein (control group or Group 2), 106 CFU/mL of formalin-killed cells of S. agalactiae vaccine incorporated in feed was also prepared (feed-based vaccine) (vaccinated group or Group 3), and unvaccinated control group or Group 4 (fed with commercial pellets). During the course of study, serum, mucus and gut lavage fluid were collected to evaluate the antibody levels via enzyme-linked immunosorbent assay (ELISA). The results showed that tilapia immunized with the feed-based recombinant vaccine developed a strong and significantly (P < 0.05) higher IgM antibody response in serum, mucus and gut lavage fluid samples compared to groups 2, 3 and 4. Following heat intervenes and intraperitoneal challenge, the rate of survivors (RPS) was 70% for the vaccinated group, and 0% for the rest of the groups. Therefore, the study revealed that the feed-based recombinant vaccine significantly provides high protection against high dose challenge in heat stress environment and enhances the production of the mucosal and humoral immunity

First report of methicillin-resistant Staphylococcus aureus from cage-cultured tilapia (Oreochromis niloticus)

Swabs from the brain, eyes and kidneys of tilapia from 11 farms were collected for a period of 2 years. They were grown on blood agar before cultures of suspected Staphylococcus aureus were subjected to ABI STAPH Detection Kit and PCR for identification. They were then grown on oxacillin resistance screening agar base (ORSAB) and subjected to PCR using the MRSA 17 kb forward and reverse primers to identify the methicillin-resistant S. aureus (MRSA). A total of 559 isolates of Staphylococcus spp. were obtained, from which 198 (35%)isolates were identified as S. aureus. Of the 198 S. aureus isolated from tilapias, 98 (50%) were identified as methicillin-resistant S. aureus (MRSA). Since global spread of multidrug-resistant bacteria has increased in the past decade, this new finding in fish should be of concern

Water Thermocline Confirms Susceptibility of Tilapia Cultured in Lakes to Streptococcus agalactiae

A study was conducted on water quality profiling to confirm susceptibility of tilapia cultured in lakes to Streptococcus agalactiae infection. A total of 1,010 and 719 tilapias of different sizes were collected from two lakes; the Kenyir and Pedu lakes, respectively. They were randomly sampled for a period of 24 months. Swabs of brain, eye and kidney were streaked directly onto blood agar before S. agalactiae was identified by the API 20 STREP kit, Slidex Strepto-kit and PCR technique. The water temperature (thermocline) and dissolved oxygen profiling were determined at 1 m intervals for up to 20 m deep. Water clarity and flow rate were also recorded using Secchi disk and a current meter. S. agalactiae was successfully isolated from both lakes throughout the year, ranging between 2 and 78%. Isolation was more frequent during the hot and dry months of both years. During this period, the mean water temperature was >29 degrees C for up to 8 m deep due to the significantly (p12 m deep. This and the slow water flow kept the water temperature at 4 m deep where tilapias under the cage culture system were kept to remain high causing stress to tilapia and increases susceptibility to S. agalactiae. Dissolved oxygen profiling, however remained high at >5 mg L-1 for up to 8 m deep and did not give adverse effects to susceptibility of tilapia to S. agalactiae

Water Thermocline Confirms Susceptibility of Tilapia Cultured in Lakes to Streptococcus agalactiae

A study was conducted on water quality profiling to confirm susceptibility of tilapia cultured in lakes to Streptococcus agalactiae infection. A total of 1,010 and 719 tilapias of different sizes were collected from two lakes; the Kenyir and Pedu lakes, respectively. They were randomly sampled for a period of 24 months. Swabs of brain, eye and kidney were streaked directly onto blood agar before S. agalactiae was identified by the API 20 STREP kit, Slidex Strepto-kit and PCR technique. The water temperature (thermocline) and dissolved oxygen profiling were determined at 1 m intervals for up to 20 m deep. Water clarity and flow rate were also recorded using Secchi disk and a current meter. S. agalactiae was successfully isolated from both lakes throughout the year, ranging between 2 and 78%. Isolation was more frequent during the hot and dry months of both years. During this period, the mean water temperature was >29 degrees C for up to 8 m deep due to the significantly (p12 m deep. This and the slow water flow kept the water temperature at 4 m deep where tilapias under the cage culture system were kept to remain high causing stress to tilapia and increases susceptibility to S. agalactiae. Dissolved oxygen profiling, however remained high at >5 mg L-1 for up to 8 m deep and did not give adverse effects to susceptibility of tilapia to S. agalactiae

Current status of acute hepatopancreatic necrosis disease (AHPND) of farmed shrimp in Malaysia

A report about a disease problem in cultured whiteleg shrimp (Penaeus vannamei) was first received by the National Fish Health Research Center (NaFisH) in 2011 from Perak State showing signs of white feces and slow death leading to serious mortality rate. Later, in September of the same year, the Malaysian Shrimp Farmers Association (MSFA) reported to Department of Fisheries (DOF) severe mortalities in almost all of the whiteleg shrimp farms throughout Peninsular Malaysia. Sampling of shrimps for disease diagnosis was then conducted by NaFisH. The bacteriological and histopathological examinations revealed respectively the isolation of V. parahemolyticus and massive sloughing of hepatopancreatic epithelial cells. The disease was subsequently identified as acute hepatopancreatic necrosis disease (AHPND). From our 3-year study, the annual prevalence rates of AHPND were 50%, 26% and 73% in 2011, 2012 and 2013, respectively. At present, AHPND still persists in Malaysia but at a lower prevalence. The risk factors associated with the disease were studied, however, varied environmental and management data analyzed were inconclusive to relate any one parameter directly to the disease. To help ensure the early detection of AHPND, an experimental observation study on `gut scorecard was carried out and this was confirmed by PCR and histopathology. Validation of this technique has yet to be carried out to ensure its reliability. We also examined the potential use of some commercial products such as probiotics and disinfectants available in the market but unfortunately results showed that they were not effective in controlling AHPND. Control measures applied by the farmers such as the use of probiotics were also verified but data generated likewise appeared to be inconclusive. On the contrary, our preliminary study on the antibacterial property of the plant extracts, i.e. betel and lemongrass, incorporated in the feed showed some prophylactic and chemotherapeutic potential against AHPND. However, comprehensive in vitro and in vivo trials are still currently being undertaken to elucidate its efficacy and practical applications. To ensure the shrimp industry s sustainability in Malaysia, results of our ongoing and future studies aimed at preventing and controlling unwarranted outbreaks of AHPND and other emerging transboundary diseases of penaeid shrimps will be continually disseminated to shrimp farmers and pertinent stakeholders

The effect of feed-based vaccination on tilapia farm endemic for streptococcosis

A tilapia farm experiencing endemic streptococcosis was selected to study the effect of vaccination with a feed-based vaccine on naturally ocurring streptococcosis. A total of 9000 red tilapia, Oreochromis niloticus × Oreochromis mossambicus of 100 ± 20 g were divided into 9 cages. Fish of Group 1 in cages 1, 2 and 3 were not vaccinated. Group 2 in cages 4, 5 and 6 were vaccinated on days 0 and 14 (single booster) while Group 3 in cages 7, 8 and 9 were vaccinated on days 0, 14 and 42 (double booster). Vaccination was done by oral administration of the feed-based bacterin vaccine at 4% bodyweight. Samples of serum for antibody study and the brain, eyes and kidney for bacterial isolation were collected at 14-day intervals. The study was carried out during the critical months between April and June. Following vaccination and booster, there was significant (p < 0.05) increase in the antibody levels in all vaccinated groups from week 1 that reached the peak at week 3 before declining gradually until week 6. However, second booster on week 6 significantly (p < 0.05) increased the antibody level that remained high until the end of the 16-week study period (double booster). Streptococcus agalactiae was isolated at the start of the experiment (day 0) at an average of 10 ± 5.0% of the sampled fish. In week 4, the isolation rate was 13 ± 5.7% but increased to 18 ± 7.6% in week 8, to 25 ± 10.0% in week 10, to 28 ± 5.8% in week 12 and 25 ± 7.3% in week 14. The average isolation rate was 28 ± 7.2%, 18 ± 7.1% and 13 ± 8.2% of the fish sampled from unvaccinated, single booster and double booster groups, respectively. At the end of the study period, the survival rate was 45.2 ± 2.45% for unvaccinated, 65.3 ± 4.8% for single booster and 75.1 ± 2.1% for double booster groups. Vaccinating fish in endemic farm might not eliminate the disease but was able to significantly improve the survival rate

Bioconversion of empty fruit bunches (EFB) and palm oil mill effluent (POME) into compost using Trichoderma virens

This study shows the performance of Trichoderma virens as an activator for conversion of empty fruit bunches (EFB) and palm oil mill effluent (POME) into compost. EFB and POME are two abundant wastes produced by oil palm industries which keep accumulating. Since there is no proper way to dispose these wastes, a potential way is to turn them into value-added product which is compost. However, normal composting will take about 4 to 6 months and additional pure fungi on compost can reduce the time to only 21 to 45 days. It also promotes plant growth and fight plant diseases. T. virens is one of the potential fungus activator and the enzyme production by this specific fungus has been studied. Biodegradation of EFB and POME supplemented with T. virens and organic N (chicken manure) gave significant changes as compared to EFB and POME alone. Application of T. virens resulted in higher xylanase and cellulase activities which lead to rapid degradation of cellulose and hemicelluloses. Compost with T. virens has higher xylanase activity on day 36 which is 4.43 �mol/(min.mg) as compared to the control which has 3.48 �mol/(min.mg). The cellulase activity is 13.214 FPU/mg and 11.314 FPU/mg for compost with T. virens and compost without bioinoculant on day 36, respectively. The N, P, K content of compost with T. virens increased significantly after maturation which is 1.304, 0.5034 and 0.645%, respectively. This result shows that T. virens played a great role by shortening the composting period of EFB and POME while producing nutrient-enriched compost

Pathological changes in red tilapias (Oreochromis spp.) naturally infected by Streptococcus agalactiae

The pathological changes present in 300 red tilapias (Oreochromis spp.) naturally infected by Streptococcus agalactiae are described. The most consistent gross findings were marked congestion of internal organs, particularly the liver, spleen and kidneys. Other features included exophthalmos, softening of the brain and the occasional accumulation of fluid within the abdominal cavity. Microscopical examination confirmed the presence of marked congestion of the liver, spleen and kidneys. The endothelial cells lining major blood vessels of the liver and occasionally the spleen were swollen and vacuolated. There was evidence of vascular thrombosis with infarction of surrounding tissue. Bacterial colonies were noted within and immediately surrounding the affected blood vessels. The meninges were thickened by the infiltration of numerous heterophils. Similar infiltrates of heterophils and lymphocytes were observed in the lamina propria of the intestine. The kidneys were severely congested and haemorrhagic, with extensive interstitial nephritis

Respon Pertumbuhan dan Produksi Tanaman Kubis Bunga terhadap Naungan dan Pupuk NPK

Budidaya kubis bunga atau bunga kol di provinsi Riau tergolong rendah dan berfluktuatif. Selama ini petani di Riau umumnya membudidayakan kubis bunga di bawah naungan. Permasalahan yang akan dihadapi dalam budidaya tanaman di bawah naungan yaitu berkurangnya intensitas cahaya yang diterima tanaman sehingga dapat berimplikasi pada penghambatan pertumbuhan dan produksi tanaman. Selain itu, peningkatan kuantitas dan kualitas hasil tanaman juga ditentukan oleh dosis pemupukan yang tepat. Adapun tujuan penelitian ini adalah untuk mengetahui respon pertumbuhan dan produksi kubis bunga terhadap naungan dan dosis pupuk NPK. Metode yang digunakan adalah Rancangan Petak tersarang dengan tiga ulangan. Faktor pertama alias petak utama yaitu intensitas naungan dengan tiga taraf perlakuan, yaitu tanpa naungan (0%), naungan 25%, dan naungan 55%. Faktor kedua atau anak petak yaitu dosis NPK 16:16:16 dengan empat taraf perlakuan, yaitu tanpa pupuk, NPK 3,7 g/tanaman, NPK 7,5 g/tanaman, dan NPK 11,2 g/tanaman. Hasil penelitian menunjukkan bahwa terdapat interaksi pada perlakuan naungan dan pupuk NPK terhadap laju pertumbuhan relatif, laju asimilasi bersih, lingkar krop dan berat krop per tanaman kubis bunga. Perlakuan naungan 0-25% memberikan produksi kubis bunga yang lebih tinggi yaitu 8.3-9.5 ton/ha dibandingkan naungan 55% (3.5 ton/ha). Pupuk NPK dengan dosis 7,5 g/tanaman mampu menunjang pertumbuhan dan produksi tanaman kubis bunga