Studies On The Morphology Of Thelohanellus Sp., And The Effects Of Water Quality And Rainfall On Its Prevalence In Puntius Gonionotus (Bleeker)

A myxosporean parasite belonging to the genus Thelohanellus, Kudo 1933 found infecting the gills of lampam jawa Puntius gonionotus (Bleeker), was studied. The morphological features of this myxosporean cysts and spores were examined through light and electron microscope to identify the species of Thelohanellus and the results were compared with other known Thelohanellus species. Morphologically, the spore size is 25.8 pm X 10.5 pm X 9.0 pm. These spores were tear-shaped or pyriform, having a distinct straight suture. Both membranous and mucous envelopes were distinctly conspicous; polar capsule size ranged from 1 1 - 1 7 pm (length) X 6-8 pm (width). Within the polar capsule were 8 - 12 coils of polar filament

Isolation and identification of pathogenic bacteria from red tilapia in cage-cultured system and its environment

Bacteria were isolated from the brain, eye and kidney of red tilapia, as well as water and debris samples. The weight and length of red tilapia were measured and the water quality as well. API test were done to identify the type of bacteria from the isolates. In Kenyir Lake, bacterial isolates that predominated in the fish were Micrococcus spp. and Aeromonas hydrophila at 13.64 %, in water samples it was Staphylococcus xylosus at 40% and in the debris samples, Pseudomonas aeruginosa and Enterobacter cloacae at 50%. In the Semantan River, the predominant bacteria in fish and debris samples were Aeromonas hydrophila at 23.53 % and 90 % respectively. In the water samples, Staphylococcus lentus and Staphylococcus xylosus were the predominant bacteria with 30 and 20%, respectively. The ammonia, sulphide, iron and nitrite-nitrogen levels in the Semantan River were over the acceptable limits and this may lead to high fish mortality. This study concluded that Aeromonas hydrophila and Staphylococcus spp. were the most predominant bacteria in red tilapia and poor water quality played a major role in red tilapia succumbing to infections by pathogenic bacteria

Control and prevention of streptococcosis in cultured tilapia in Malaysia: a review

Streptococcosis in cultured fishes has been reported to cause severe economic losses to the aquaculture industry worldwide. Lancefield group B Streptococcus agalactiae has been recognised as the main pathogen in cultured tilapia. This review discusses the current scenario and risk factors of streptococcosis in tilapia and suggests the control and prevention measures for this disease. The preventive measures focus on combined aspects of selecting farm location, applying good aquaculture farm practices, utilization of antibiotics and proper vaccination programme. A combination of all these measures will perhaps be the key to improve the health of cultured tilapia and prevent the infection by S. agalactiae, which in turn will increase the economic profit of tilapia farm operators

Relationship of scrotal circumference to age, body weight and onset of spermatogenesis in goats

Scrotal circumference (SC) and body weight (BW) measurements were obtained from 122 crossbred (Saanen × Loca; Jumnapari × Local) bucks, ranging in age from 3 to 28 months. Spermatogenesis and semeniferous tubule diameters were studied from testicular biopsies in 24 bucks. The results showed that SC increased curvilinearly and was significantly correlated with age (P < 0.05). Scrotal circumference correlated more significantly with BW (P < 0.001). Spermatogenesis was completed at 6–7 months with a sudden increase in tubular diameter at the same time. Since SC is an indirect measurement of testicular size, a marked increase in testicular size indicated the onset of active spermatogenesis and, hence, the possibility of using bucks for breeding at an earlier age than normally recommended. Further, SC norms obtained in this study may become useful in the evaluation of bucks for breeding soundness

Efficacy of feed-based adjuvant vaccine against Streptococcus agalactiae in Oreochromis spp. in Malaysia.

This study was conducted to determine the systemic, mucosal immunity and protective capacity of the feed-based adjuvant vaccine (FAV) of Streptococcus agalactiae following oral vaccination against streptococcosis in tilapias. Two hundred and sixteen red tilapia fish were divided into three major groups. Each major group consisted eight tilapia kept in nine 2000 L glass aquaria. At day 0, all fish from the FAV group were fed with feed that had been incorporated with an adjuvant, while fish in the feed-based vaccine (FNV) group were fed with vaccine incorporated into the pellet without adjuvant. Fish in the control-unvaccinated group, FC, were fed with normal commercial pellet. Booster dose was performed on day 14 post immunization. Fish from each group were sacrificed on a weekly basis for the entire 7 weeks. Serum, body mucus and gut lavage fluid were evaluated for antibody responses by indirect ELISA, while histological examination was carried out on the gut following intraperitoneal challenge. The FAV group had a significantly higher protection (P < 0.05) following challenge with 3.4 × 109 CFU mL−1 of live S. agalactiae than FNV group. This level of protection may be due to high antibody responses, increase in size of gut-associated lymphoid tissue and high number of lymphocytes in the FAV grou

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

Determination of LD50 for Streptococcus agalactiae and Staphylococcus aureus infections in tilapia

One hundred and sixty fingerlings and 80 adult tilapias were experimentally infected with Streptococcus agalactiae and Stapylococcus aureus to determine their LDso. Four concentrations of Streptococcus agalactiae (109, 108,107, 106 CFU/mL) were used in this experimental infection. These tilapias were divided into 4 groups of 40 fingerlings and 20 adults per group. Groups 1, 2, 3 and 4 of the fingerlings were exposed to 109, 10,107, 106 CFU/mL of S. agalactiae by immersion in 2 L inoculum solution for 20 min. Similarly, the adult groups were exposed to the same concentrations of S. agalactiae but by intraperitoneal injection at the rate of 1 mL of the inoculum per gram. Similar procedures were repeated using exposure to Staphylococcus aureus alone or a combination of S. agalactiae and S. aureus. All test groups were observed for signs of infections. On Day 7 post-infection (pi), all fish that were still alive were humanely killed. The LDso of the adult tilapia that were exposed to S. agalactiae, S. aureus or mixed infection was 2.3884 x 107,2.8151 X 108 , and 4.2409 x io', respectively. For the fingerling groups, the LDso for S. agalactiae, S. aureus, and mixed infection was 2.9242 x 1020,2.8665 x 1017 , and 4.9748 x IO!', respectively. Experimental infection in adults could be established within 12 h post-injection to 6.3 x 109 CFU per mL and 9.7 x 109 CFU per mL of S. agalactiae and S. aureus, respectively. For fingerlings, infection could be established within 72 h following bath immersion to 6.3 x 109 CFU per mL and 9.7 x 109 CFU per mL of S. agalactiae and S. aureus, respectively

The effects of oral vaccination of Streptococcus agalactiae on stimulating gut-associated lymphoid tissues (GALTs) in tilapia (Oreochromis spp.)

Vaccination of fish by intraperitoneal (i.p.) injection and bath immersion against bacterial infections has been proven to be a commercial success. However, those routes of vaccination are not economical in practice due to several reasons such as high labour cost, highly time consuming, and causing stress to the fish. Meanwhile, oral vaccination is considered as the best route to vaccinate the fish due to less stress to the fish, ability to treat large batch at one time, and easy and practical to administer booster vaccination. In this study, effect of oral vaccination with various regimes in stimulating gut-associated lymphoid tissues (GALTs) against Streptococcus agalactiae infection was observed. In this vaccination experiments, four groups of fish with four replicates consisting of 15 tilapias each were used; four groups per treatment received antigen incorporated vaccine in different regimes. Group 1 was fed with vaccine once per week, Group 2 was fed three consecutive days per week, and Group 3 was fed five consecutive days per week, while Group 4 (control) was fed with standard commercial feed. Booster dose was administered at day-14 after the first administration, and humanely killed at day-28 post-booster vaccination. Ten fish from each group were collected for gut sampling and subjected for histological analysis using Olympus FIVE Image Analyzer. Aggregations of GALTs were observed in lamina propria of the gut. The sizes of GALTs were measured and the numbers of lymphoid cells were also counted. The diameter of GALTs showed no significant (p>0.05) difference between Groups 1 to Group 2 and Group 2 to Group 3, but a significant difference (p0.05) were found between Group 1 to Group 2 and Group 2 to Group 3; however, a significant difference (p<0.05) was observed between Groups 1 and Group 3. As a conclusion, the frequencies of administration play a role in stimulating the size of GALT which is correlated with the number of aggregated lymphoid cells in the gastrointestinal tract of tilapia

Molecular characterization of aeromonas hydrophila isolated from pangasius hypophthalmus (sauvage, 1878) in Pahang river, Malaysia

Pahang, Malaysia are very famous of its Pangasius spp (Patin) aquaculture activity. Pangasius spp. has excellent potential for inland aquaculture system with its fast growing ability and good market value in European markets (Singh and Lakra, 2012).Pangasius spp. is one of the largest and most important inland fisheries in the world which mainly contribute as a food source. The production of Pangasius spp. in Malaysia showed tenfold increased from 1,625.21 tonnes in 2000 to 10,891.51 tonnes in 2011. However, Pangasius culture has been reported to face disease problem causing almost 30% mortalities especially in Sungai Pahang and Sungai Kuantan due to multiple infections of bacteria and virus. The reported bacterial disease was Motile Aeromonas Septicemia (MAS) while virus is channel catfish virus (CCV). Thus, the aim of this study is to understand Aeromonas hydrophila that had cause MAS infection in Pangasius hypophthalmus at Pahang River. Bacteria were collected from liver, kidney and spleen of Pangasius hypophthalmus cultured in Pahang River Malaysia. Isolated bacteria were cultured onto Brain Heart Infusion (BHI) Agar and identified using Gram staining, biochemical tests and API systems. Aeromonas spp. isolates were then subjected to conventional Polymerase Chain Reaction (PCR) using 16s rRNA gene and ITS gene. The amplified genes were sent for DNA sequencing and the results were tested with BLASTn to search for any sequence similarity with other bacteria in the Genebank. Construction of phylogenetic tree was carried out using MEGA 6 software. From the DNA sequencing method, isolates obtained were confirmed as Aeromonas hydrophila. Neighbor-joining method of phylogenetic tree constructed also reveals that the genetic variation of the isolates is similar with Aeromonas hydrophila from China and India. Thus, this information will facilitate to trigger a better prevention and treatment against MAS