The present study examined the pharmacokinetics and bioavailability of oxytetracycline (OTC) in black tiger shrimp (
Penaeus monodon) after intra-sinus (10 mg/kg) and oral (50 mg/kg) administration ...in water (salinity of 5 ppt) at 29–30 °C and also investigated the net changes of OTC residues in the shrimp using cooking procedures (boiling, baking and frying). The hemolymph concentrations of OTC after intra-sinus dosing were best described by a two-compartment open model. The distribution and elimination half-lives were found to be 0.20 h and 16.2 h, respectively. The apparent volume of distribution at a steady state and the total body clearance were estimated to be 869 ml/kg and 38.7 ml/kg/h, respectively. The bioavailability of OTC after an oral administration in black tiger shrimp was found to be 35.6%. The hemolymph protein binding in vivo of OTC was 49.0
±
7.6%. The protein binding was constant over the concentration range tested at each sampling time point. The peak hemolymph concentration, the time to peak hemolymph concentration and the elimination half-life were found to be 21.1 μg/ml, 4 h and 16.4 h, respectively. The residual OTC was rapidly eliminated from muscle with the elimination half-life value of 22.0 h. The OTC levels in muscle fell below the MRL (0.2 μg/g) at 120 h post-dosing. However, the OTC level in shell increased to a high level (6.27 μg/g) at 10 h post-administration and had not decreased at the last sampling time (120 h). OTC residues were lower in all cooked samples than in corresponding raw samples. Residual OTC in muscle was reduced by 30–60% by boiling, baking and frying, whereas in shell, OTC was reduced by 20% in every cooking method.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Vibrio vulnificus is the major pathogenic bacterium causing mass mortality in groupers (Epinephelus spp.) culture with symptoms as skin and fins hemorrhages and ulcerative necrosis. Microbiological ...and biochemical characterizations were used to identify Vibrio spp., but it is ambiguous to distinguish V. vulnificus and others. Therefore, molecular genotypic analysis was applied to identify and typing Vibrio spp. isolated from the diseased grouper. Firstly, the identification of Vibrio spp. was assessed by 16 s rRNA before generating the phylogenetic tree. It revealed that 40 samples from 63 samples were V. vulnificus biotype 1. After that, all V. vulnificus samples were classified into subgroup by molecular biotyping based on the 22 virulence genes identification. Accordingly, V. vulnificus can be categorized as subgroup 1, 2, and 3 (marked as G1, G2, and G3, respectively) based on the presence of those studied virulence genes. V. vulnificus isolates containing 16 virulence genes of vvpE, gloB, tlh, Mann Hemo, ManIIA, rimO, vllY, OmpU, vvhA, rtx, hlyIII, pilF, Mann TRAP, vcgC, 16S rRNA type B and nanA has been classified as subgroup 1, whereas subgroup 2 has shown the additional 4 genes including YJ-like nab 1, YJ-like nab 2, cps and sodA, as well as subgroup 3 harboring CM-like nab 1, CM-like nab2, and sodA. Surprisingly, different identification method using 10 house-keeping genes in multi-locus sequence typing (MLST) represented the new three different sequence type (ST) profile. Additionally, phenotypic analysis of isolated V. vulnificus was also performed through the disk diffusion method. This result demonstrated that G1 and G2 were susceptible to tetracycline at 44.4% and 53.8%, respectively, while G3 was susceptible to oxytetracycline (46.2%). Interestingly, G2 which lacking CM-like nab1 and CM-like nab2 alleles exhibited the highest virulent pathogenicity, despite showing a slower growth rate than G1 and G3. Meanwhile, G3, lacking cps gene but containing CM-like nab1 and CM-like nab2 alleles, did not cause mortality in experimental challenge fish. In the case of inactivated vaccine efficiency trial, the FKC-Mixed vaccine revealed the best efficacy when compared with other vaccinated groups (P < 0.05). Altogether, our findings suggested that the molecular genotyping analysis is useful for identifying Vibrio spp. and may apply as the appropriate platform for further characterization of other bacterial species.
•V. vulnificus isolated from Diseased, Brown-Marbled Grouper (Epinephelus Fuscoguttatus) was biotype 1 with 3 distinct subgroups.•All those 3 subgroups of V. vulnificus were identified as new sequence type (ST) or new allelic profile.•Different subgroups of V. vulnificus showed different phenotypes including pathogenicity, growth rate, and antimicrobial susceptibility profile.•Multiplex-PCR of virulence genes of V. vulnificus could distinguish all those 3 subgroups of V. vulnificus and specific to V. vulnificus but not with others Vibrio spp.•Preliminary analysis on efficacy of inactivated whole cell vaccine demonstrated that combined vaccine showed lowest cumulative mortality.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Early mortality syndrome (EMS) refers to acute mortality within approximately 35 days of shrimp culture. It is often equated with acute hepatopancreatic necrosis disease (AHPND) caused by Vibrio ...isolates that produce Pir-like toxins. To better understand EMS, 200 Thai shrimp ponds were randomly selected prior to stocking and subsequently sampled from 19/08/2013 to 23/04/2014 to determine the pond prevalence of various pathologies, and particularly those targeting the shrimp hepatopancreas (HP). Ponds exhibiting acute mortality within 35 days were labeled EMS ponds while others were labeled non-EMS ponds. Shrimp samples from each pond (10) were subjected to histological analysis focused on hepatopancreatic (HP) lesions. Similar samples (10) were tested by PCR for the microsporidian Enterocytozoon hepatopenaei (EHP), white spot syndrome virus (WSSV), yellow head virus (YHV) and Vibrio that cause AHPND. Preservation failed for 4 ponds. Results from the 196 ponds remaining were divided, into 4 groups based largely on HP histology: (1) ponds positive for AHPND by histology and/or PCR at 20.9% prevalence (41/196); (2) ponds showing HP bacterial lesions at 14.8% prevalence (29/196); (3) ponds showing collapsed HP tubule epithelia at 25.0% prevalence (49/196); and (4) ponds showing no HP pathology (normal HP) at 39.3% prevalence (77/196) ponds. The overall prevalence of EMS ponds (i.e., mortality ≤35 days) was 16.3% (32/196), but only 18/32 (56.3%) of these fell within AHPND Group 1. The other 14 EMS ponds (43.7%) were divided among the remaining three groups: Group 2 with HP bacterial lesions (3/32 = 9.4%), Group 3 with collapsed HP tubule epithelia (1/32 = 3.1%) and Group 4 with normal HP histology (a surprising 10/32 = 31.2%). Across all groups, prevalence of ponds exhibiting aggregated transformed microvilli (ATM) was high at 79.8%, as was prevalence of EHP at 60.7%. The overall prevalence of WSSV was low at 4.1% (8/196), while YHV was not found. Overall, the results indicated that equating EMS with AHPND without confirmatory analysis could lead to overestimation of its impact on shrimp aquaculture and to failure in recognizing other important causes of early mortality.
•Determination of shrimp pathogens and pathologies were carried out in the 200 pre-selected Thai shrimp ponds.•Among 196 ponds examined, 32 ponds were reported to be EMS ponds.•Only 18 in 32 EMS ponds were found to be positive for AHPND by histology and/or PCR.•Shrimp EMS is not equal to AHPND.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Growth‐related traits are the main target of genetic breeding programmes in grouper aquaculture. We constructed genetic linkage maps for tiger grouper (Epinephelus fuscoguttatus) and giant grouper ...(E. lanceolatus) using 399 simple sequence repeat markers and performed a quantitative trait locus (QTL) analysis to identify the genomic regions responsible for growth‐related traits in F1 hybrid grouper (E. fuscoguttatus × E. lanceolatus). The tiger grouper (female) linkage map contained 330 markers assigned to 24 linkage groups (LGs) and spanned 1,202.0 cM. The giant grouper (male) linkage map contained 231 markers distributed in 24 LGs and spanned 953.7 cM. Six QTLs affecting growth‐related traits with 5% genome‐wide significance were detected on different LGs. Four QTLs were identified for total length and body weight on Efu_LG8, 10, 13 and 19 on the tiger grouper map, which explained 6.6%–12.0% of the phenotypic variance. An epistatic QTL with a reciprocal association was observed between Efu_LG8 and 10. Two QTLs were identified for body weight on Ela_LG3 and 10 on the giant grouper map, which explained 6.9% of the phenotypic variance. Two‐way analysis of variance indicated that the QTL on Efu_LG13 interacts with the QTLs on Ela_LG3 and 10 with large effects on body weight. Furthermore, these six QTLs showed different features among the winter, summer and rainy seasons, suggesting that environmental factors and fish age affected these QTLs. These findings will be useful to understand the genetic structure of growth and conduct genetic breeding in grouper species.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
Forty five strains of marine bacteria which showed inhibitory activities against bacterial swarming were isolated from larval black tiger shrimp (Penaeus monodon), brine shrimp (Artemia salina) ...nauplii and rearing seawater in Thailand. These marine bacteria were examined by a double-layer plate method for their growthinhibiting abilities against 50 strains of vibrios isolated from similar sources. As a result, 27 strains among 45 marine bacteria examined inhibited 32 to 94% of the vibrios tested. These Vibrio-inhibiting strains also exhibited inhibitory activities against 52 to 96% of the reference strains of 27 species of Vibrio including fish and shellfish pathogens. The inhibition was exhibited bactericidally, and antibiotics were produced extracellularly and inactivated by heat treatment at 70°C for 30 min. All the 27 strains of antibiotic producers were identified as Alteromonas-like organisms based on their taxonomical characteristics including G + C values of DNA (42.4-45.3 mol %).
This study examined the pharmacokinetics and bioavailability of oxolinic acid (OA) in black tiger shrimp Penaeus monodon Fabricius, in brackish water (salinity 10 g L−1) at 28–29°C, after intra‐sinus ...(10 mg kg−1) and oral (50 mg kg−1) administration and also investigated the net changes of OA residues in the shrimp after cooking (boiling, baking and frying). The haemolymph concentrations of OA after intra‐sinus dosing were best described by a two‐compartment open model. The distribution and elimination half‐lives were 0.84 and 17.7 h respectively. The apparent volume of distribution at a steady state and the total body clearance were estimated to be 2061 mL kg−1 and 90.1 mL kg−1 h−1 respectively. The bioavailability of OA after an oral administration was 7.9%. The peak haemolymph concentration, the time to peak haemolymph concentration and the elimination half‐life after oral administration were 4.20 μg mL−1, 4 h and 19.8 h respectively. Oxolinic acid muscle and shell levels increased to a maximum (muscle 1.76 μg g−1 and shell 8.17 μg g−1) at 4 h post administration and then decreased with the elimination half‐life value of 20.2 and 21.9 h respectively. Residual OA in muscle and shell was reduced by 20–30% by each cooking procedure examined.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
The distribution of oxytetracycline (OTC) in male and female Macrobrachium rosenbergii was examined after the prawns had been given medicated feed containing OTC at levels of 2.5 and 5.0 g/kg of feed ...for 1 week and nonmedicated feed thereafter. OTC levels in the heads of both male and female prawns were consistently higher than in the muscles. Batches of both male and female prawns treated with higher dosages had significantly higher OTC residues in both head and muscle tissues than the batches treated with lower dosages. During treatment, peak concentrations in the head and muscle from each group were reached within 4−6 days. After drug treatment ceased, 13 days for the head and 10 days for the muscle were required to reduce OTC residues to safe levels in all batches of both sexes and dosages. In practice, to account for variations in water temperature, drug dosage, duration of therapy, and other environmental conditions, a withdrawal period of 21 days is recommended. Keywords: Giant freshwater prawn; Macrobrachium rosenbergii; male; female; withdrawal period
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IJS, KILJ, NUK, PNG, UL, UM, UPUK
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