Pharmacokinetics and residues of florfenicol in Nile tilapia (Oreochromis niloticus) post-oral gavage.

In the study on Oreochromis niloticus, singular oral gavage of florfenicol (FFC) at 15 mg/kg biomass/day was conducted, mimicking approved aquaculture dosing. Samples of plasma, bile, muscle, intestine, skin, liver, kidney, gill, and brain tissues were collected at 0, 2, 3, 4, 6, 8, 12, 16, 24, 32, 48, 64, 96, and 128 hours (h) after oral gavage. LC-MS/MS analysis revealed FFC concentrations peaked at 12.15 µg/mL in plasma and 77.92 µg/mL in bile, both at 24 hours. Elimination half-lives were 28.17 h (plasma) and 26.88 h (bile). The residues of FFC ranked muscle>intestine>skin>liver>kidney>gill. In contrast, the residues of florfenicol amine (FFA) ranked kidney>skin>liver>muscle>gill>intestine>brain, particularly notable in tropical summer conditions. The minimum inhibitory concentration of FFC was elucidated against several bacterial pathogens revealing its superior efficacy. Results highlight bile's crucial role in FFC elimination. Further investigation, especially during winter when fish susceptibility to infections rises, is warranted.

Influence of dietary emamectin benzoate on the biological responses of monosex (all-male) Oreochromis niloticus (L.) fries.

The application of antiparasitic drugs plays a crucial role in the removal of infectious parasites in aquaculture. Emamectin benzoate (EB) is predominantly used as a feed premix against ectoparasites on temperate fish. This study evaluated the influence of 14 days of EB-dosing at 0-10 times the recommended dose (1X: 50 µg/kg biomass/day) on the biological responses and accrual/depletion of EB-residues in a tropical fish monosex Oreochromis niloticus fries. A significant dose-dependent reduction in feed intake by 3.50% in 1X and 43.00% in 10X groups, and an increase in mortalities from 2.92% (1X) to 11.25% (10X) during the EB-dosing period was noted. A significant increase in glucose and alkaline phosphatase and reduction in calcium and chloride ions, superoxide dismutase (SOD) and acetylcholinesterase levels in the muscle and/or brain tissue was observed. On day 21 post-EB-dosing, the levels of muscle glucose and SOD reached normalcy in the 1X group, while the levels of other biomarkers failed to recuperate. The EB-residue levels peaked on day 14 EB-dosing (2.77 ng/g) in the 1X group and decreased later with detectable levels (0.03 ng/g) even on day 21 post-EB-dosing. The EB-residue levels were within the permissible limits of the Canadian Food Inspection Agency and the European Commission. The EB-dosing negatively influenced the health of O. niloticus by altering the physiological state in a dose- and time-dependent way. The results suggested that the use of EB might be plausibly risky in tropical aquaculture.

Influence of Fluctuating Water Temperature and Dietary Oxytetracycline on the Safety of Monosex Nile Tilapia Oreochromis niloticus Fries.

The influence of fluctuating water temperature and dietary oxytetracycline (OTC) at 0 (0X), 80 (1X), 240 (3X), 400 (5X) and 800 mg (10X)/kg biomass/day for 30 consecutive days on the safety of monosex (all male) Nile tilapia Oreochromis niloticus fries in terms of feeding, growth, survival and histopathology of vital organs were assessed. A dose-dependent decline in feed intake and biomass was recorded. The OTC-dosed groups recorded higher mortalities than the control. The therapeutic OTC-dosing (1X) in conjunction with low temperature caused 75.56 ± 8.01% mortality and 25.75% reduced feed intake in 30 days. The mortalities increased with increasing OTC-doses from 85.19 ± 3.39% (1X) to 95.56 ± 2.22% (10X) and fluctuating temperature (12.00-21.50°C) even after the withdrawal of OTC. Relatively mild to moderate histopathological lesions were observed in the kidney, liver and intestine of OTC-dosed fries. These results suggested that dietary OTC and low water temperature may cause adverse effects on monosex O. niloticus fries.

Safety of emamectin benzoate administered in feed to Nile tilapia Oreochromis niloticus (L.).

Emamectin benzoate (EB) premix top-coated onto feed is extensively used to treat ectoparasitic crustacean infestations in aquaculture. This study evaluated the safety of EB-dosing in Nile tilapia Oreochromis niloticus at the recommended dose and dosage of 50 µg/kg biomass/day for 7 consecutive days (1X) and compared with control and 10 times the recommended dose (10X). Depletion of EB-residues in the edible muscle of 1X-dosed Nile tilapia was also studied. Mortality, behavioural changes, feed consumption, biomass, EB-residue depletion, and histopathological alterations in the kidney, liver and intestine were determined at slated intervals. Significant dose-dependent reduction in feed intake and biomass and insignificant mortalities were noted in 1X and 10X EB-dosed fish. In 1X EB-dosed fish muscle, the residues peaked on day 7 EB-dosing (9.72 ng/g) and decreased subsequently. Nevertheless, the residue levels were within the acceptable limit of the European Commission and the Canadian Food Inspection Agency even during the EB-dosing period. Histologically, tubule degeneration in the kidney, mild glycogen vacuolation in the liver, and loss of absorptive vacuoles, inflammation and disintegration of the epithelial layer in the intestine of Nile tilapia fed the 1X EB-diet were observed. The fish reverted back to their normal functions with time upon termination of oral-EB-dosing. This work contributed scientific data on the safety of EB particularly on the feed intake, growth reduction, mortality, histopathological alterations, and EB-residue levels in the edible tissues of Nile tilapia fed at the recommended dose and dosage, which suggested that EB-therapy might be reasonably risky in a tropical climate.

Efficacy evaluation of ethanolic extract of Tamarindus indica L. leaves as possible alternate therapy in septic arthritis model of rabbit.

BACKGROUND: Our previous study exhibited free radicals scavenging and antioxidant activities of ethanolic and aqueous extracts of Tamarindus indica L. leaves in chronic sodium fluoride poisoning in rats. Tamarindus indica L. seed extract was also reported to have anti-arthritic efficacy by inhibiting cartilage and bone degrading factors. Therefore, an attempt was made to evaluate the effects of ethanolic extract of Tamarindus indica L. leaves in septic arthritis. METHODS: The safety study was performed by oral dosing of ethanolic extract of the plant leaves at 2 g kg- 1 for consecutive 28 days in rabbits. Septic arthritis was induced in rabbits by single intra-articular inoculation of 104 c.f.u. of Staphylococcus aureus to the left stifle joint and was monitored by bacterial colony count, some relevant biochemical parameters and histopathological interpretation of the affected joint. For efficacy evaluation in septic arthritis, linezolid at 75 mg kg- 1 twice daily for 10 days and the ethanolic extract of Tamarindus indica L. at 500 and 1000 mg kg- 1 for consecutive 14 days were administered orally to the rabbits after 48 h of induction of arthritis. RESULTS: In sub-acute toxicity study of Tamarindus indica L. leaves ethanolic extract, no significant change between days was found for aspertate aminotransferase, alanine transaminase, alkaline phosphatase, blood urea nitrogen and creatinine compared to day 0 values of the same group. The bacterial colony count of synovial fluid following Staphylococcus aureus inoculation to left stifle joint was found to be 1.08 ± 0.47 and 1.19 ± 0.29 c.f.u. mL- 1 in ethanolic extract low dose and high dose groups respectively, on day 2 which was reduced to 0.057 ± 0.036 c.f.u. mL- 1 and nil on day 16. The test extract was also found to markedly reduce simultaneous glucose difference, total protein ratio of serum and synovial fluid, joint radius and joint narrowing. CONCLUSION: Ethanolic extract of Tamarindus indica L. leaves at 500 mg kg- 1 and 1000 mg kg- 1 produced anti-arthritic effects against S. aureus induced septic arthritis in rabbits. However, the ethanolic extract at 1000 mg kg- 1 orally for consecutive 14 days showed better effects in septic arthritis.

Disposition of ceftizoxime in Staphylococcal mastitis in Indian crossbred cows.

Disposition of ceftizoxime was studied in Indian crossbred cows following a single IV dosing in field conditions. Six healthy lactating and six mastitic crossbred cows were assigned to two groups (Group 1 and Group 2). A single IV administration of ceftizoxime at the dose rate of 20mg/kg was administered to cows in both groups. Peak concentrations were recorded at 5min, decreasing sharply until 1h with plasma concentrations of 46.38±0.30µg/mL; concentrations were below detection limits at 24h. Ceftizoxime achieved peak concentrations at 96h and persisted up to 120h at a concentration of 36.71±0.96µg/mL in the milk of mastitic Indian crossbred cows. Staphylococcal colony count in acute mastitis was 52.33±4.98×105 colony forming units/mL milk and no growth was detected at 96h post-dosing, indicating that ceftizoxime following single IV administration at 20mg/kg may be effective to treat acute staphylococcal mastitis.

Potential of a polyherbal drug to prevent antimicrobial resistance in bacteria to antibiotics.

Persistence of antibacterial drugs for prolonged period in milk increases the probability of antimicrobial resistance progress. Ceftizoxime was found to be excreted in milk for a prolonged period in goats, cows and buffaloes following intravenous injection of ceftriaxone and ceftizoxime. A single dose of ceftriaxone was administered intravenously in healthy control goats (group I) and a single oral dose of the commercial mammary protective polyherbal drug (1.9 gm) was given one hour prior to intravenous ceftriaxone injection in healthy (group II) and induced mastitic (group III) goats to evaluate milk disposition of ceftizoxime following single intravenous dosing of ceftriaxone at 42.25 mg kg-1.Ceftriaxone/ceftizoxime was analyzed by HPLC. The t1/2α and t1/2ß values were 14.755 ± 2.733 and 149.079 ± 18.565 hour, respectively indicating prolonged persistence of ceftizoxime in milk. The polyherbal drug increased the milk concentration at later hours and hastened the excretion of ceftizoxime from milk compared to control group. Ceftriaxone could not be detected in milk. The study suggested that adjunct single or repeated therapy of  the polyherbal drug may cause non persistence of ceftriaxone and shorter persistence of ceftizoxime in milk.

Prevalence of CTX-M-Producing Klebsiella spp. in Broiler, Kuroiler, and Indigenous Poultry in West Bengal State, India.

This study was undertaken to detect the prevalence of CTX-M-producing Klebsiella spp. in healthy broiler, indigenous, and kuroiler birds reared in West Bengal (India) during November 2014-February 2015. In addition to CTX-M gene, the study was also conducted to reveal the occurrence of other ß-lactamase and class I integron genes in Klebsiella spp. isolates along with their clonal relationship. A total of 321 cloacal swabs from healthy broiler, indigenous, and kuroiler birds were collected from different places of West Bengal, India. Klebsiella spp. isolation rate varies among different types of poultry birds (43.8-72.3%). In total, 33 (10.7%) Klebsiella spp. isolates were detected phenotypically as CTX-M producers and all the isolates possessed blaCTX-M in polymerase chain reaction. Whereas 17 (51.5%) and 16 (48.5%) Klebsiella spp. isolates possessed blaSHV, and blaTEM with blaCTX-M, respectively. None of the CTX-M-producing Klebsiella spp. isolates in this study possessed class I integron gene. Randomly amplified polymorphic DNA-based phylogenetic tree revealed the presence of clonal relationship among the CTX-M-producing Klebsiella spp. isolates, recovered from broilers and indigenous birds. This study identified broilers and indigenous game birds as a potential reservoir of CTX-M-producing Klebsiella spp., which could be transmitted to the human food chain directly or indirectly.

Efficacy evaluation of Bauhinia variegata L. stem bark powder as adjunct therapy in chronic Staphylococcus aureus mastitis in goat.

OBJECTIVE: The objective was to study the effect of Bauhinia variegata L. stem bark powder as adjunct therapy in chronic Staphylococcus aureus mastitis in goat. MATERIALS AND METHODS: Mastitis was induced by intracisternal inoculation of coagulase positive S. aureus (J638) at the concentration of 2000 colony forming units. Group I animals were treated with repeated dose of ceftriaxone at 20 mg/kg intravenously, and Group II animals were treated with once daily oral administration of B. variegata L. stem bark powder at 6 g/kg for 7 days followed by maintenance dose at 3 g/kg for next 7 days along with repeated dose of the antibiotic at 20 mg/kg intravenously at 4 days interval. RESULTS: No significant improvement in the clinical condition of the udder was noticed in the group treated with repeated dose of ceftriaxone alone. However, in the group treated with B. variegata L. stem bark powder along with repeated dose of ceftriaxone, no S. aureus colony was seen at 96 h and onwards in milk samples with a marked decrease in somatic cell count and milk alkaline phosphatase activity and increased lactoperoxidase activity. Further, plasma and milk concentration of ceftriaxone/ceftizoxime was increased, which indicated antibacterial, bioenhancing and antiinflammatory properties of the bark powder. The Group II animals also exhibited marked reduction in polymorphonuclear cells and fibrous tissue indicating antifibrotic property of B. variegata L. CONCLUSION: B. variegata L. stem bark powder can be considered as an effective adjunct therapy to intravenous ceftriaxone in S. aureus chronic mastitis in goat.

Monitoring of pesticide residue in bovine milk from Nadia district, West Bengal.

Monitoring of 210 bovine milk samples collected from local markets in the Nadia district of West Bengal during 2011 was performed. Samples were collected in summer and winter seasons. Analysis of pesticides was performed by using a multiresidue method validated in the laboratory. The quantification was performed using GC-ECD. Analysis revealed the presence of lindane in less than 1 % of milk samples. Endosulfan I and II were also detected and were found to exceed MRL recommended by Codex. Overall 1.90 % of the analyzed samples showed trace to measurable amount of pesticide residues. The monitored area provided pesticide residues data of milk, assisting in future scientific assessment on pesticide usage.

Disposition of ceftriaxone in hepatopathic goats following single-intramuscular dosing.

Hepatopathy sometimes may interfere with metabolism and/or elimination of drugs which undergo major hepatic clearance. Twelve healthy goats were equally divided into two groups (I and II) and hepatopathy was induced by carbontetrachloride in the second group (group II). A single dose of ceftriaxone at 50 mg/kg was administered to each group intramuscularly. Disposition of ceftriaxone in plasma of healthy goats showed a typical absorption-reabsorption phase. However, the reabsorption phase was totally absent in hepatopathic goats and the disposition of ceftriaxone showed only absorption and distribution/elimination phase. The drug persisted in plasma for 6 h in hepatopathic animals, whereas the drug can only be detected up to 2 h in healthy animals indicating longer persistence of ceftriaxone in the former group. Ceftizoxime, the active metabolite of ceftriaxone was available in urine of group I animals, whereas only ceftriaxone was detected in the urine of hepatopathic animals suggesting impairment of metabolism of the parent drug in hepatopathy. Therefore, the reabsorption and metabolism of ceftriaxone in goats should be taken into consideration for drug monitoring.

Quantitative imaging of arsenic and its species in goat following long term oral exposure.

Severity of arsenic toxicity was reported to vary depending on its species. The present study reflects the status of different species of arsenic in goat following long-term exposure of arsenic leading to hepatic damage. The experiment was conducted with six black Bengal goats, which were administered with sodium arsenite orally at a dose rate of 2 mgkg(-1) daily for 84 days. Faeces, urine, hair and blood samples were collected from those animals at 14 days interval. Excretion of total arsenic was reduced from 56 days onwards through both faeces and urine indicating higher accumulation of arsenic in body. The speciation study revealed that urinary arsenic was mainly of organic type, whereas hair accumulated almost equal proportion of arsenite, arsenate and organo arsenicals. Goats excreted high proportion of organo arsenicals through faeces possibly due to hepatobiliary secretion of organo arsenic into the gut. Significantly elevated serum alanine aminotransferase and aspartate aminotransferase activities (p<0.05) along with histopathological changes in liver indicated hepatotoxicity. The arsenite fraction increased and organic proportion decreased in urine as the time progressed, which indicates that arsenite gets methylated in liver of goat. The study thus alluded that the toxicity of arsenic would aggravate if the animals were exposed for long time as the hepatotoxicity progressed resulting in decreased methylation and formation of organo arsenicals and decreased excretions through urine.

Pharmacokinetic interaction of intramammary ceftriaxone and oral polyherbal drug (Fibrosin(®)) in goats.

BACKGROUND: The aim of the present study was to determine pharmacokinetic interaction of ceftriaxone and polyherbal drug (Fibrosin(®)) in lactating goats following single dose intramammary administration of ceftriaxone with 1 h pre-single dose oral administration of Fibrosin(®). METHODS: Pharmacokinetic interaction of ceftriaxone and Fibrosin(®) was evaluated in lactating goats following single dose intramammary administration of ceftriaxone at 50 mg/kg with 1 h pre-single dose oral administration of Fibrosin(®) (1.9 g). Estimation of ceftriaxone and its metabolite, ceftizoxime, was determined by high performance liquid chromatography. RESULTS: Fibrosin(®) treated goats showed a typical absorption-reabsorption phase of ceftriaxone in plasma following intramammary administration. Neither ceftriaxone nor ceftizoxime was detected in the plasma and urine of goats without Fibrosin(®) treatment, however, ceftriaxone persisted for 36 h and ceftizoxime was present from 48 h to 72 h in the plasma of Fibrosin(®) treated goats. Ceftizoxime was also available from 72 h to 360 h post-dosing in milk in the presence of Fibrosin(®) following intramammary administration of ceftriaxone suggesting the polyherbal drug played a major role in the penetration of ceftriaxone from milk to systemic circulation. Furthermore, the polyherbal drug increased the bioavailability of ceftizoxime in milk following the metabolism of ceftriaxone. CONCLUSIONS: Polyherbal drug (Fibrosin(®)) plays a major role in the penetration of ceftriaxone from milk to systemic circulation and may be responsible for increased bioavailability of its metabolite in the mammary gland resulting in higher concentration and longer persistence of the drug in milk.

Pharmacokinetics of ceftriaxone in carbontetrachloride-induced hepatopathic and uranyl nitrate-induced nephropathic goats following single dose intravenous administration.

The pharmacokinetic profile of ceftriaxone was studied in female healthy goats, induced hepatopathic and nephropathic goats after a single intravenous dose at 50 mg kg(-1). Ceftriaxone persisted for 2 h in plasma of hepatopathic goats compared to 1 h of healthy goats, but the kinetic behaviour followed 'one-compartment open model' in both healthy and hepatopathic goats. Mean value of t((1/2))beta (0.32 +/- 0.008 h) was significantly higher in hepatopathic goats compared to healthy goats (0.19 +/- 0.002 h). Ceftriaxone was recovered at 24 h in urine of hepatopathic goats but it could not be detected in urine of healthy goats. However, its metabolite ceftizoxime was present in urine of healthy goats but not in urine of hepatopathic goats. On the other hand ceftriaxone persisted for 2 h in plasma of kidney damaged goats with significant higher concentration compared to healthy goats but kinetic behaviour followed 'one Compartment open model'. Ceftizoxime was identified with an adequate plasma concentration from 8 h to 12 h post dosing in nephropathic goats. Elimination halflife (t(1/2)beta) of Elimination ceftriaxone (0.38 +/- 0.01 h) in nephropathic goats increased significantly compared to healthy goats (0.19 +/- 0.002 h). Ceftriaxone, not the metabolite ceftizoxime was recovered at 24 h and 48 h post dosing in urine of nephropathic goats, while only ceftizoxime not ceftriaxone was detected in urine of healthy goats.