Selenium Nanoparticles: Revolutionizing Nutrient Enhancement in Aquaculture - A Review

Aquaculture, a cornerstone of global food production, confronts myriad challenges including disease outbreaks and environmental degradation. Achieving nutritionally balanced aquafeed is critical for sustainable production, prompting exploration into innovative solutions like selenium nanoparticles (SeNPs). SeNPs offer potent antimicrobial, antioxidant, and growth-promoting properties, bolstering gut immunity and digestive capacity in aquatic animals. Their high bioavailability and ability to traverse gut barriers make them promising candidates for aquafeed supplementation. This study investigates SeNPs as a cutting-edge solution to enhance nutrient supply in aquaculture, addressing key challenges while promoting environmental stewardship and food security. By synthesizing current research and highlighting future directions, this review provides valuable insights into sustainable aquaculture practices. SeNPs hold promise for revolutionizing aquaculture feed formulations, offering a pathway to improved production outcomes and environmental sustainability.

Pharmacokinetics of toltrazuril and its metabolite, toltrazuril sulfone, in suckling piglets following oral and intramuscular administrations

Toltrazuril (TZR) is currently the only registered chemotherapeutic drug in the European Union for the treatment of Cystoisospora suis. This study investigated the comparative pharmacokinetics and tissue concentration-time profiles of TZR and its active metabolite, toltrazuril sulfone (TZR-SO2 ), after oral (per os, p.o.) and intramuscular (i.m.) administration to suckling piglets. Following a single administration of TZR orally at 50 mg/piglet or intramuscularly at 45 mg/piglet, higher concentrations of TZR and TZR-SO2 were observed in all three investigated tissues after p.o. administration. The mean TZR concentration in serum peaked at 14 μg/mL (34.03 h) and 5.36 μg/mL (120 h), while TZR-SO2 peaked at 14.12 μg/mL (246 h) and 9.92 μg/mL (330 h) after p.o. and i.m. administration, respectively. TZR was undetectable in the liver after p.o. administration (18 days) and in the jejunum (24 days) after i.m. injection, while TZR-SO2 was still detectable in all three tissues after 36 days regardless of administration routes. This study showed that p.o. formulation exhibited faster absorption and higher serum/tissue TZR/TZR-SO2 concentrations than i.m. formulation. Both formulations generated sufficient therapeutic concentrations in the serum and jejunum, and sustained enough time to protect against Cystoisospora suis infection in the piglets.

Epidemiology of Severe Fever with Thrombocytopenia Syndrome in Dogs and Cats in Taiwan

Severe Fever with Thrombocytopenia Syndrome (SFTS), caused by the SFTS Virus (SFTSV), is a global health threat. SFTSV in Taiwan has only been reported in ruminants and wild animals. Thus, we aimed to investigate the infection statuses of dogs and cats, the animals with closer human interactions. Overall, the SFTSV RNA prevalence was 23% (170/735), with dogs showing a 25.9% (111/429) prevalence and cats at 19.3% (59/306) prevalence. Noticeably, the prevalence in stray animals (39.8% 77/193) was significantly higher than in domesticated ones (17.2%, 93/542). Among the four categories analyzed, the highest SFTSV prevalence was found in the stray dogs at 53.9% (120/193), significantly higher than the 24.2% prevalence noted in stray cats. In contrast, domesticated animals exhibited similar prevalence rates, with 17.1% for dogs and 17.2% for cats. It is noteworthy that in the domesticated animal groups, a significantly elevated prevalence (45%, 9/20) was observed among cats exhibiting thrombocytopenia compared to those platelet counts in the reference range (4.8%, 1/21). The high infection rate in stray animals, especially stray dogs, indicated that exposure to various outdoor environments influences the prevalence of infections. Given the higher human interaction with dogs and cats, there is a need for proactive measures to reduce the risk associated with the infection of SFTSV in both animals and humans.

Serotypes, virulence factors and multilocus sequence typing of Glaesserella parasuis from diseased pigs in Taiwan

Background

Glaesserella parasuis (G. parasuis) belongs to the normal microbiota of the upper respiratory tract in the swine, but virulent strains can cause systemic infections commonly known as Glässer's disease that leads to significant economic loss in the swine industry. Fifteen serotypes of G. parasuis have been classified by gel immunodiffusion test while the molecular serotyping based on variation within the capsule loci have further improved the serotype determination of unidentified field strains. Serovar has been commonly used as an indicator of virulence; however, virulence can be significantly differ in the field isolates with the same serotype. To date, investigations of G. parasuis isolated in Taiwan regarding antimicrobial resistance, serotypes, genotypes and virulence factors remain unclear.

Methods

A total of 276 G.parasuis field isolates were collected from 263 diseased pigs at the Animal Disease Diagnostic Center of National Chiayi University in Taiwan from January 2013 to July 2021. Putative virulence factors and serotypes of the isolates were identified by polymerase chain reaction (PCR) and antimicrobial susceptibility testing was performed by microbroth dilution assay. Additionally, the epidemiology of G. parasuis was characterized by multilocus sequence typing (MLST).

Results

Serotype 4 (33.3%) and 5 (21.4%) were the most prevalent, followed by nontypable isolates (15.9%), serotype 13 (9.4%), 12 (6.5%), 14 (6.2%), 7 (3.3%), 1 (1.8%), 9 (1.1%), 11 (0.7%) and 6 (0.4%). Nine out of 10 putative virulence factors showed high positive rates, including group 1 vtaA (100%), fhuA (80.4%), hhdA (98.6%), hhdB (96.0%), sclB7 (99.6%), sclB11 (94.9%), nhaC (98.2%), HAPS_0254 (85.9%), and cirA (99.3%). According to the results of antimicrobial susceptibility testing, ceftiofur and florfenicol were highly susceptible (>90%). Notably, 68.8% isolates showed multidrug resistance. MLST revealed 16 new alleles and 67 new sequence types (STs). STs of these isolated G. parasuis strains were classified into three clonal complexes and 45 singletons by Based Upon Related Sequence Types (BURST) analysis. All the G. parasuis strains in PubMLST database, including strains from the diseased pigs in the study, were defined into two main clusters by Unweighted Pair Group Method with Arithmetic Mean (UPGMA). Most isolates in this study and virulent isolates from the database were mainly located in cluster 2, while cluster 1 included a high percentage of nasal isolates from asymptomatic carriers. In conclusion, this study provides current prevalence and antimicrobial susceptibility of G. parasuis in Taiwan, which can be used in clinical diagnosis and treatment of Glässer's disease.

The Use of Tricaine Methanesulfonate (MS-222) in Asian Seabass (Lates calcarifer) at Different Temperatures: Study of Optimal Doses, Minimum Effective Concentration, Blood Biochemistry, Immersion Pharmacokinetics, and Tissue Distributions

This study was conducted to determine the optimal doses and minimum effective concentrations (MECs) of tricaine methanesulfonate (MS-222) in marketable-size Asian seabass reared at two temperatures (22 and 28 °C). Serum biochemical parameters, pharmacokinetics, and tissue distributions of MS-222 following immersion at the determined optimal doses were also evaluated in order to delineate possible mechanisms dictating the temperature difference. The definition of optimal dose is set as the dose when fish attain stage III anesthesia within 5 min, sustain this stage for 3 min, and re-attain equilibrium within 5 min. The MEC is the fish serum MS-222 concentration when stage III anesthesia is reached. The results showed that water temperature exerted no or minimal impact on the designated parameters. The optimal doses at 22 and 28 °C were 140 and 150 µg/mL, while the MECs were 70.48 and 78.27 µg/mL, respectively. Fish exposed to the optimal doses of MS-222 had significantly elevated blood concentrations of lactate, glucose, calcium, magnesium, and sodium, while the blood pH was significantly decreased. The fish eliminated MS-222 faster at 28 °C than at 22 °C, with serum half-lives of 18.43 and 37.01 h, respectively. Tissue-specific distribution patterns were evident. Irrespective of water temperature, MS-222 peaked at 5 min for the brain and gill but peaked slightly later at 10-20 min for the liver and kidney. Most tissues exhibit a gradual decline of drug concentration except for the gill, which was maintained at a steady level. Muscle is the least perfused tissue with the lowest drug concentration throughout the 90 min period. This study provided physiological and pharmacokinetic evidence contributing to a better understanding of the actions of MS-222 in Asian seabass at different temperatures.

Serotype and multilocus sequence typing of Streptococcus suis from diseased pigs in Taiwan

Streptococcus suis (S. suis) infection can cause clinically severe meningitis, arthritis, pneumonia and septicemia in pigs. To date, studies on the serotypes, genotypes and antimicrobial susceptibility of S. suis in affected pigs in Taiwan are rare. In this study, we comprehensively characterized 388 S. suis isolates from 355 diseased pigs in Taiwan. The most prevalent serotypes of S. suis were serotypes 3, 7 and 8. Multilocus sequence typing (MLST) revealed 22 novel sequence types (STs) including ST1831-1852 and one new clonal complex (CC), CC1832. The identified genotypes mainly belonged to ST27, ST94 and ST1831, and CC27 and CC1832 were the main clusters. These clinical isolates were highly susceptible to ceftiofur, cefazolin, trimethoprim/sulfamethoxazole and gentamicin. The bacteria were prone to be isolated from cerebrospinal fluid and synovial fluid in suckling pigs with the majority belonging to serotype 1 and ST1. In contrast, ST28 strains that corresponded to serotypes 2 and 1/2 were more likely to exist in the lungs of growing-finishing pigs, which posted a higher risk for food safety and public health. This study provided the genetic characterization, serotyping and the most current epidemiological features of S. suis in Taiwan, which should afford a better preventative and treatment strategy of S. suis infection in pigs of different production stages.

Effects of starvation on the pharmacokinetics and optimal dosages of florfenicol and associated serum biochemistry in Asian seabass (Lates calcarifer)

Starvation has influence on physiology and pharmacokinetic (PK) characteristics of many drugs in land animals. However, similar PK information in fish is lacking. The current study examined the effects of starvation on fish PK, taking florfenicol (FF) in Asian seabass as an example. FF was orally administered at a single dose of 10 mg/kg into 35-day starved fish reared at 25 and 30°C and the serum FF concentration was analyzed by HPLC-FLD. At 30°C, the absorption and elimination half-lives of the starved fish were increased by 30% (from 0.44 to 0.57 h) and 55% (from 7.2 to 11.18 h), respectively. The volume of distribution, clearance, and area under the curve were changed from 1.25 to 0.71 L/kg, 0.120 to 0.044 L/kg/h, and 88 to 228 h·μg/ml, respectively. Similar starvation-induced PK changes were also observed at 25°C. The serum biochemical parameters, mainly the alanine aminotransferase, aspartate aminotransferase, and glucose levels, were significantly reduced in the starvation group. Overall, FF absorption, distribution, and elimination rates were reduced by starvation, resulting in four to five times lower optimal dosage than the non-starved fish. Drug treatment in starved fish should be treated with caution as overdosing and/or tissue residues could perceivably occur.

Effects of temperature on the pharmacokinetics, optimal dosage, tissue residue, and withdrawal time of florfenicol in asian seabass (lates calcarifer)

Drug behavior in the bodies of fish is largely influenced by the water temperature. Antimicrobial drugs are needed for the control of bacterial outbreaks in farmed fish including Asian seabass (Lates calcarifer). However, little is known about the temperature effect on appropriate drug uses in this species. The purpose of this study was to investigate the differences in pharmacokinetics (PK), optimal dosages, tissue depletion, and withdrawal time (WDT) of florfenicol (FF) in Asian seabass reared at 25 and 30 °C. In the PK study, the fish were administered with a single oral dose of 10 mg/kg FF. The optimal dosing regimen was determined by the pharmacokinetic-pharmacodynamic (PK-PD) approach. In the tissue depletion and WDT study, FF was administered at the optimal dosages once daily for 5 days and the WDT was determined by linear regression analysis based on the sum of FF and its metabolite florfenicol amine (FFA) in the muscle/skin. When the temperature was increased from 25 to 30 °C, the elimination half-life of FF was significantly decreased from 11.0 to 7.2 h. While the other PK parameters were not changed significantly, the calculated optimal dosages for the target minimum inhibitory concentration (MIC) of 2 µg/mL were 10.9 and 22.0 mg/kg/day, respectively for 25 and 30 °C. The sum of FF + FFA is a preferable marker residue for WDT determination because differential FF metabolism was observed at different temperatures. The depletion half-life of the muscle/skin was shortened from 41.1 to 32.4 h by the 5 °C temperature increase. Despite different absolute amounts of FF given between the two temperature levels, the WDTs were very similar at 6-7 days. Thus, it appears that a single temperature-independent WDT can potentially be assigned when the drug was applied at the optimal dosage.

Pharmacokinetics, optimal dosages and withdrawal time of florfenicol in Asian seabass (Lates calcarifer) after oral administration via medicated feed

Asian seabass (Lates calcarifer) is an economically important fish in Asian and Australian markets, but few pharmacokinetic (PK) data of antimicrobial drugs in this species is available. The present study investigated the PK behaviour of florfenicol (FF) through medicated feed in Asian seabass cultured at 25°C. The serum and muscle/skin concentrations of FF and its metabolite florfenicol amine (FFA) were determined by the HPLC-FLD method and analysed by one-compartmental model. The optimal dosages were determined by pharmacokinetic-pharmacodynamic (PK-PD) approach and the linear regression analysis was used to determine the withdrawal time (WDT). The PK study following a single oral administration of 15 mg/kg FF via medicated feed revealed that the absorption half-life (t_1/2Ka ), elimination half-life (t_1/2K ), peak concentration (C_max ), area under the concentration-time curve (AUC), volume of distribution (Vd/F) and clearance (CL/F) were 1.47 h, 8.07 h, 8.61 μg/ml, 146.41 h·μg/ml, 1.19 L/kg and 0.102 L/kg/h, respectively. The muscle/skin concentration-time profile was similar to that of the serum, suggesting well distribution but only a small fraction of FF was metabolized to FFA. The optimal dosage for a minimum inhibitory concentration of 2 μg/ml was calculated as 13.38 mg/kg/day. The appropriate WDT after multiple oral medications with 15 mg/kg FF once daily for 7 days was determined as 8 days. Information obtained from the current study can potentially be applied for the treatment of bacterial diseases in farming Asian seabass.

Effect of Carbonyl Cyanide Chlorophenylhydrazone on Intrabacterial Concentration and Antimicrobial Activity of Amphenicols against Swine Resistant Actinobacillus pleuropneumoniae and Pasteurella multocida

Effects and mechanism of carbonyl cyanide chlorophenylhydrazone (CCCP) on antimicrobial activity of florfenicol (FF) and thiamphenicol (TAP) were investigated against amphenicol-resistant Actinobacillus pleuropneumoniae and Pasteurella multocida isolated from diseased swine. Broth microdilution and time-kill assays indicated that CCCP dose-dependently and substantially (4-32 fold MIC reduction) improved amphenicol antimicrobial activity. When combined with CCCP at the lowest literature reported dose (2-5 μg/mL), 85% FF resistant A. pleuropneumoniae and 92% resistant P. multocida showed significantly reduced FF MICs (≥ 4-fold). In contrast, none or few of the susceptible A. pleuropneumoniae and P. multocida had FF MICs reduction ≥ 4-fold. 90% FF resistant A. pleuropneumoniae and 96% resistant P. multocida carried the floR gene, indicating strong association with the FloR efflux pump. With CCCP, the intracellular FF concentration increased by 71% in floR+ resistant A. pleuropneumoniae and 156% in floR+ resistant P. multocida strains but not the susceptible strains. The degree of reduction in TAP MICs was found consistently in parallel to FF for both bacteria. Taken together, partially attributed to blockage of drug-efflux, the combination of FF or TAP with CCCP at sub-cytotoxic concentrations was demonstrated and showed feasibility to combat amphenicol-resistant A. pleuropneumoniae and P. multocida isolated from diseased swine.

Combined Effects of Temperature and Salinity on the Pharmacokinetics of Florfenicol in Nile Tilapia (Oreochromis niloticus) Reared in Brackish Water

Prudent antimicrobial use requires knowledge of pharmacokinetics (PK) in a specific fish species which in turn depends on water temperature and salinity. Although the influence of each individual factor is known, the combined effect is less clear. The objective of the current study was to investigate the effect of temperature and salinity concurrently on the PK of florfenicol (FF) in Nile tilapia reared in brackish water. Twenty-eight fish were divided into four groups and kept at one of two temperatures (24 vs. 32°C) and two salinity levels (5 vs. 15 ppt). The FF was administered at a single dose of 15 mg/kg body weight via oral gavage. The serum concentrations were analyzed by HPLC method and the PK parameters were analyzed by a 2-compartmental model. The result revealed that at 32°C, the elimination half-lives (t_1/2β), time to reach the peak concentration (T_max), area under the serum concentration-time curve (AUC), and mean residence time (MRT) were significantly decreased, while the clearance relative to bioavailability (CL/F) significantly increased compared to those at 24°C. The extents of these PK changes were similar at the two salinity levels. On the contrary, increasing the salinity from 5 to 15 ppt at a given temperature level produced no significant change in the PK behavior. Our finding indicated that only water temperature, but not salinity, is the major determinant factor governing the FF fate in the fish body.

Effects of spray-dried animal plasma on growth performance, survival, feed utilization, immune responses, and resistance to Vibrio parahaemolyticus infection of Pacific white shrimp (Litopenaeus vannamei)

Spray-dried animal plasma (SDP) in feed for several animal species provides health benefits, but research about use of SDP in shrimp feed is very limited. The objectives of the present study were to investigate the effects of dietary SDP on growth performance, feed utilization, immune responses, and prevention of Vibrio parahaemolyticus infection in Pacific white shrimp (Litopenaeus vannamei). In Experiment 1, the post-larvae were divided into five groups (four tank/group and 80 shrimp/tank) and fed four times daily diets with porcine SDP at 0, 1.5, 3, 4.5, and 6% of the diet for 45 days. In Experiment 2, the surviving shrimp from Experiment 1 were redistributed into six groups: four SDP groups as in Experiment 1 plus the positive and negative controls (four tank/group and 30 shrimp/tank). They were then challenged with V. parahaemolyticus by immersion at 10⁵ colony-forming units (CFU)/mL and were fed with the same diets for another 4 days. In Experiment 1, shrimp fed 4.5% or 6% SDP diets had significantly higher body weight, survival rate, and improved feed conversion ratio. The immune parameters (total hemocyte count and phagocytic, phenoloxidase, and superoxide dismutase activities) of the shrimp fed 3–6% SDP diets also showed significant enhancement compared to the control. In Experiment 2, the survival rates of the 3–6% SDP groups were significantly higher than the positive control at day 4 after the immersion challenge. Likewise, the histopathological study revealed milder signs of bacterial infection in the hepatopancreas of the 3–6% SDP groups compared to the challenged positive control and 1.5% SDP groups. In conclusion, shrimp fed diets with SDP, especially at 4.5–6% of the diet, showed significant improvement in overall health conditions and better resistance to V. parahaemolyticus infection.

Determination of Optimal Doses and Minimum Effective Concentrations of Tricaine Methanesulfonate, 2-Phenoxyethanol and Eugenol for Laboratory Managements in Nile Tilapia (Oreochromis niloticus)

Simple Summary

Fish studies often require anesthetic drugs to render the fish amenable for experimental handling and to secure animal welfare. However, the optimal dose is not always available. In this study, we determined the optimal does of three commonly used anesthetics, eugenol (EUG), tricaine methanesulfonate (MS-222), and 2-phenoxyethanol (2-PE), for induction of surgical anesthesia in marketable-size Nile tilapia, and decided on their minimum effective concentrations (MEC) in the fish serum. The results revealed that the optimal doses of EUG, MS-222, and 2-PE were 90, 300, and 900 ppm, and their MECs were 53, 70, and 263 µg/mL, respectively. Increasing the anesthetic doses generally resulted in the shortening of the induction times, but variably affected the recovery times. In contrast, the MECs were found to be independent of the administered doses. After the dosing was stopped, the serum concentrations of anesthetics decreased rapidly, lowering by >90% within the first hour and by >99% after 4 h. Our research provides practical information for a smooth fish handling and offered insights for designing researches requiring surgical anesthesia.

Abstract

Anesthetic agents are often used in fish experiments to reduce the stress and struggle and to improve animal welfare. The present study aimed to determine the optimal doses and serum minimum effective concentration (MEC) of tricaine methanesulfonate (MS-222), 2-phenoxyethanol (2-PE), and eugenol (EUG) in Nile tilapia. Twenty-one fish were immersed in three different doses of each anesthetic and the minimal dose that produce stage III anesthesia within 5 min, maintain anesthesia status for 3 min, and recover within 5 min was considered the optimal dose. The serum concentrations of anesthetics immediately after the fish reached stage III anesthesia was defined as the MEC. The results revealed that the anesthetics dose-dependently shorten the induction time while the effect of doses on the recovery times were variable. The determined optimal doses for MS-222, 2-PE, and EUG were 300, 900, and 90 ppm, respectively. The MECs were 70, 263, and 53 µg/mL, respectively, about two to four times lower than the optimal doses and were independent of the doses. After immersion stopped, the serum concentrations decreased by >90% within the first hour and >99% after 4 h. Our research provides useful information for a smooth fish handling and design for researches requiring stage III anesthesia.

Epidemiological survey of Toxoplasma gondii and Neospora caninum infections in dairy goats in Central-Southern Taiwan

Toxoplasma gondii and Neospora caninum are intracellular protozoan parasites that cause reproductive disorders in ruminants and humans. Information on the risk factors of T. gondii and N. caninum infections in goats is very limited in Taiwan. The aim of the study was to investigate the epidemiology and identify the risk factors of these two infections in goats. A total of 630 caprine sera were collected from 42 dairy goat farms and the owners were interviewed by a structured questionnaire. The apparent seroprevalences of T. gondii in farm- and individual- levels were respectively 88.1% and 32.22%, while those of N. caninum were 19.05% and 2.54%, respectively. Toxoplasma gondii B1 gene was identified in 7 feed samples and 8 from the water samples whereas N. caninum was not found. Wooden flooring was the main risk factor for T. gondii infection while the frequency of visits by staff to other farms and the breed of goat were risk factors for N. caninum. The improvement of flooring materials or thorough cleaning, periodic disinfection and maintenance of dryness on the floor are highly recommended for the prevention of T. gondii infection in farmed goats. In addition, unnecessary visits to other farms should be limited to prevent the spread of N. caninum. These factors should be highlighted for the prevention of T. gondii and N. caninum in goats, particularly when raised in intensive housing system with flooring on height.

Single amino acid utilization for bacterial categorization

Despite great advancement in genetic typing, phenotyping is still an indispensable tool for categorization of bacteria. Certain amino acids may be essential for bacterial survival, growth, pathogenicity or toxin production, which prompts the idea that the intrinsic ability to utilize single amino acid under live-or-die situation could be a basis for differentiation of bacteria species. In this study, we determined the single amino acid consumption profiles of 7 bacterial species, and demonstrated that most bacteria have species-specific pattern of amino acid consumption. We also discovered that bacterial strains from different hosts, toxigenicity, and antibiotic-resistance presented distinct preference for certain amino acids. Taken altogether, the amino acid consumption profiles showed potential to be a novel tool complementary to study not only bacterial categorization but also biochemical characteristics of the bacteria such that its phenotyping can be used to uncover strategies for nutritional, pharmaceutical, taxonomic, and evolutionary aspects of bacterial researches.

Bath immersion pharmacokinetics of florfenicol in Nile tilapia (Oreochromis niloticus)

Drug administration by immersion can be a preferable method in certain conditions especially for treating small-sized, anorexic, or valuable fish. Pharmacokinetic information regarding bath treatment is considerably lacking in comparison to other common administration routes. The current study aimed to investigate if immersion can be an effective route to administer florfenicol (FF) for treatment in Nile tilapia. Nile tilapia reared at 28°C were immersed with FF solution at concentrations of 50, 100, 200, 500, and 500/200 (3 hr/117 hr) ppm for 120 hr and moved to drug-free freshwater for another 24 hr. The serum FF concentration in 100, 200, and 500/200 ppm groups reached steady-state at 12 hr with concentrations of 2.44, 3.04, and 5.26 µg/ml, respectively, which were about 2% of the bathing concentrations. The target therapeutic levels of 1-4 µg/ml were attained and maintained within 1-12 hr, depending on the immersion concentration and the target MIC. Serum FF reached the target with shorter time at higher bathing concentration. Following the 120-hr bath, the serum FF declined with the first-order half-life of approximately 10 hr. A minimum of 100 ppm FF is required for treatment purpose, and an initial high loading concentration followed by maintenance concentration is a plausible way to reach in vivo therapeutic level in short time. Greater than 99% of the residual FF in the bathing water could be removed within 15 min by 0.05% NaOCl. Our results indicated that bath immersion is a promising potential route for FF administration in Nile tilapia.

Establishment of feline in-house reference intervals for hematologic and biochemical parameters and potential age-related differences

Reference intervals (RIs) are one of the essential elements in the procedure of disease diagnosis. This is especially true for feline species in which RI is less available than in canine species. RIs are affected by biological, geographical and instrumental factors, yet published RIs with incomplete background are popularly used. Inappropriate interpretations of RIs may affect classification of disease and subsequent treatment. In this study, we demonstrated the step-by-step establishment of feline RIs following the American Society for Veterinary Clinical Pathology (ASVCP) reference interval guideline. A total of 51 parameters were examined, including 20 hematology and 31 biochemistry parameters, and the results were compared to one local RI and two foreign RIs. Overall, about 29% (10/35) of tested parameters were different form local RIs and 60% (30/50) were different from the two foreign RIs, highlighting geographical variations. A higher upper reference limit (URL) in red blood cell count (RBC), hematocrit (Hct), Hemoglobin (Hgb), albumin, creatinine and lower URL in potassium and white blood cell count (WBC) were identified, which may impact the interpretation. In addition, statistical analysis of age and gender were factored separately and indicated that 10 parameters were significantly higher in the adult group. For the impact of gender, percentage of basophil and total iron-binding capacity (TIBC) were lower in female and male cats, respectively. In conclusion, we have demonstrated that it is desirable to establish in-house RIs or RIs of local sources. An age specific RI for the geriatric feline population is advisable for better diagnosis and monitoring the disease.

The effects of crossbreeding, age, and sex on erythrocyte indices and biochemical variables in crossbred pet rabbits (Oryctolagus cuniculus)

BACKGROUND

A number of domestic rabbit (Oryctolagus cuniculus) breeds exist, and the pet rabbit population consists of a variety of pure- and crossbred animals. However, the reference intervals (RIs) for rabbits are limited by outdated methods and a single-breed source.

OBJECTIVE

This study aimed to establish more complete, updated erythrocytic and biochemical RIs for the crossbred pet rabbit population to improve routine diagnostic accuracy in clinical practice, and to examine the effects of crossbreeding on erythrocytic and biochemical parameters.

METHODS

Blood specimens were collected from 85 clinically healthy crossbred pet rabbits representing a wide range of breeds. RIs for the erythrocyte indices and 12 chemistry analytes were determined as recommended by the American Society for Veterinary Clinical Pathology guidelines. The results were compared with four widely used RIs. Age and sex differences for all variables were statistically analyzed.

RESULTS

The results diverged from the RIs for New Zealand white rabbits, indicating that not all RIs from this species are appropriate for use in exotic animal practices. Breed-associated variations were evident for aspartate amino transferase, alkaline phosphatase, and glucose, while crossbreed effects were found for total protein, albumin, blood urea nitrogen, creatinine, calcium, and phosphate. Statistically significant differences and clinical relevance among age groups were detected for hemoglobin, hematocrit, and creatinine.

CONCLUSIONS

Establishing RIs specifically for crossbred pet rabbits is desirable for clinicians treating pet rabbits of various breeds and ages. Age-specific RIs for this population warrants further investigation.

The first discovery of severe fever with thrombocytopenia syndrome virus in Taiwan

Severe fever with thrombocytopenia syndrome (SFTS), an emerging tick-borne zoonosis, has been rapidly spread in many Asian counties since 2010, which raises the great concern in East Asia. Nevertheless, the infection status of SFTS in Taiwan remains unclear. To investigate the existence of SFTSV in Taiwan, a total of 151 serum samples collected from 31 sheep, 63 bovine and 57 dogs were enrolled this study. Furthermore, 360 adult female Rhipicephalus microplus were also included. One-step RT-nested PCR and IgG ELISA were conducted to test SFTSV specific RNA and antibodies, respectively. The result provided the first evidence of the existence of SFTSV RNA and antibodies in ruminants and ticks in Taiwan.

In vitro and in vivo Synergistic Effects of Florfenicol and Thiamphenicol in Combination Against Swine Actinobacillus pleuropneumoniae and Pasteurella multocida

Potential synergism between florfenicol (FF) and thiamphenicol (TAP) was investigated for in vitro efficacy against Actinobacillus pleuropneumoniae and/or Pasteurella multocida as well as in vivo efficacy in swine. Among isolates of A. pleuropneumoniae (n = 58) and P. multocida (n = 79) from pigs in Taiwan that were tested, high percentages showed resistance to FF (52 and 53%, respectively) and TAP (57 and 53%, respectively). Checkerboard microdilution assay indicated that synergism [fractional inhibitory concentration index (FICI) ≤ 0.5] was detected in 17% of A. pleuropneumoniae (all serovar 1) and 24% of P. multocida isolates. After reconfirming the strains showing FICI ≤ 0.625 with time kill assay, the synergism increased to around 32% against both bacteria and the number could further increase to 40% against resistant A. pleuropneumoniae and 65% against susceptible P. multocida isolates. A challenge-treatment trial in pigs with P. multocida showed that the FF + TAP dosage at ratios correspondent to their MIC deduction was equally effective to the recommended dosages. Further on the combination, the resistant mutation frequency is very low when A. pleuropneumoniae is grown with FF + TAP and similar to the exposure to sub-inhibitory concentration of FF or TAP alone. The degree of minimum inhibitory concentration (MIC) reduction in FF could reach 75% (1/4 MIC) or more (up to 1/8 MIC for P. multocida, 1/16 for A. pleuropneumoniae) when combined with 1/4 MIC of TAP (or 1/8 for A. pleuropneumoniae). The synergism or FICI ≤ 0.625 of FF with oxytetracycline (47%), doxycycline (69%), and erythromycin (56%) was also evident, and worth further investigation for FF as a central modulator facilitating synergistic effects with these antimicrobials. Taken together, synergistic FF + TAP combination was effective against swine pulmonary isolates of A. pleuropneumoniae and P. multocida both in vitro and in vivo. Thus, this study may offer a potential alternative for the treatment of A. pleuropneumoniae and P. multocida infections and has the potential to greatly reduce drug residues and withdrawal time.

Nanoparticulated Honokiol Mitigates Cisplatin-Induced Chronic Kidney Injury by Maintaining Mitochondria Antioxidant Capacity and Reducing Caspase 3-Associated Cellular Apoptosis

Cisplatin is a potent anti-cancer drug, however, its accompanied organ-toxicity hampers its clinical applications. Cisplatin-associated kidney injury is known to result from its accumulation in the renal tubule with excessive generation of reactive oxygen species. In this study, we encapsulated honokiol, a natural lipophilic polyphenol constituent extracted from Magnolia officinalis into nano-sized liposomes (nanosome honokiol) and examined the in vivo countering effects on cisplatin-induced renal injury. We observed that 5 mg/kg body weight. nanosome honokiol was the lowest effective dosage to efficiently restore renal functions of cisplatin-treated animals. The improvement is likely due the maintenance of cellular localization of cytochrome c and thus preserves mitochondria integrity and their redox activity, which as a consequence, reduced cellular oxidative stress and caspase 3-associated apoptosis. These improvements at the cellular level are later reflected on the observed reduction of kidney inflammation and fibrosis. In agreement with our earlier in vitro study showing protective effects of honokiol on kidney cell lines, we demonstrated further in the current study, that nanosuspension-formulated honokiol provides protective effects against cisplatin-induced chronic kidney damages in vivo. Our findings not only benefit cisplatin-receiving patients with reduced renal side effects, but also provide potential alternative and synergic solutions to improve clinical safety and efficacy of cisplatin treatment on cancer patients.

Pharmacokinetic-pharmacodynamic modelling for the determination of optimal dosing regimen of florfenicol in Nile tilapia (Oreochromis niloticus) at different water temperatures and antimicrobial susceptibility levels

Optimized dosing regimen is key to the effective use of antibacterials and to minimizing drug-related side effects. The current study established a pharmacokinetic-pharmacodynamic (PK-PD) model for the determination of optimal antibacterial dosing regimen in fish taken into consideration the temperature-dependent PK and the pathogen-dependent antimicrobial susceptibility, using florfenicol (FF) in Nile tilapia as an example. The calculated optimal dosages significantly varied by temperature and target MIC levels, ranging from 2.23 (MIC 1 µg/ml at 24°C) to 34.88 mg kg^-1  day^-1 (MIC 4 µg/ml at 32°C). The appropriateness of the calculated dosages was successfully verified by the in vivo studies. After 5 days of oral administration of the calculated optimal dosage at 24°C, the predicted plasma drug values were in line with the mean observed C_min(ss) while at 28 and 32°C underestimation of the C_min(ss) in a dose-dependent manner was observed and likely due to the occurrence of non-linear PK at high dosages. The averaged serum protein binding of FF was 19.1%. Our results demonstrated the appropriateness and clinical applicability of the developed PK-PD approach for the determination of optimal dosing regimens at given temperatures and MICs. Saturation metabolism and PK non-linearity of FF in tilapia warrant further study.

The association of indoxyl sulfate with fibroblast growth factor-23 in cats with chronic kidney disease

Background

Indoxyl sulfate (IS) has been reported not only to increase with the severity of impaired renal function, but also possibly to be a factor associated with bone abnormalities linked to fibroblast growth factor‐23 (FGF‐23) in humans with chronic kidney disease (CKD). It is not yet known whether this correlation between IS and FGF‐23 holds true for cats with CKD.

Hypothesis

Accumulation of IS is related to FGF‐23 secretion in cats with CKD.

Animals

Twenty clinically healthy cats and 73 cats with CKD cases were evaluated retrospectively.

Methods

The concentrations of IS and FGF‐23 in plasma were determined by high‐performance liquid chromatography and ELISA, respectively. Progression was defined as an increment of 0.5 mg/dL of serum creatinine concentration within 3 months.

Results

Plasma IS and FGF‐23 concentrations were significantly increased concurrently with decreasing renal function. Higher concentration of FGF‐23 was significantly associated with higher concentration of IS after adjusting for various confounding factors including creatinine and phosphate. Furthermore, the correlation between IS and phosphate was higher than that between FGF‐23 and phosphate. When the renal progression group was compared with the non‐progression group, both IS and FGF‐23 were found to be significantly increased (P < .05). In addition, the area under receiver operator curve of the combination of IS and FGF‐23 predicted renal progression at a level >0.9.

Conclusions and Clinical Importance

Both FGF‐23 and IS are associated with phosphate metabolism and CKD progression.

Honokiol, a Polyphenol Natural Compound, Attenuates Cisplatin-Induced Acute Cytotoxicity in Renal Epithelial Cells Through Cellular Oxidative Stress and Cytoskeleton Modulations

Cisplatin is a potent anti-cancer drug that has been widely used in the treatment of various cancers; however, cisplatin administration results in severe nephrotoxicity and impedes its clinical applications. In this study, we showed that honokiol, a polyphenol constituent extracted from Magnolia officinalis exhibited a short-term protective effect against cisplatin-induced damages in renal epithelial cells in vitro. The protective effects of honokiol were resulted from the combination of (1) reduced cellular oxidative stress ranging from 53 to 32% reduction during a 24-h incubation, (2) the maintenance of cellular antioxidant capacity and (3) the stabilization of cytoskeletal structure of the kidney epithelial cells. By promoting the polymerization of actin (1.6-fold increase) and tubulin (1.8-fold increase) cytoskeleton, honokiol not only maintained epithelial cell morphology, but also stabilized cellular localizations of tight junction protein Occludin and adhesion junction protein E-Cadherin. With stabilized junction protein complexes and structural polymerized cytoskeleton network, honokiol preserved epithelial cell polarity and morphology and thus reduced cisplatin-induced cell disruption and damages. Our data demonstrated for the first time that honokiol could counteract with cisplatin-induced damages in renal epithelial cells in vitro, future in vivo studies would further validate the potential clinical application of honokiol in cisplatin-based cancer treatments with reduced nephrotoxicity.

Effect of teapot materials on the chemical composition of oolong tea infusions

BACKGROUND

The flavor and quality of tea are widely believed to be associated with the pot in which the tea is made. However, this claim is mostly by experiences and lacks solid support from scientific evidence. The current study investigated and compared the chemical compositions of oolong tea made with six different teapot materials, namely Zisha, Zhuni, stainless steel, ceramic, glass and plastic.

RESULTS

For each tea sample, polyphenols and caffeine were examined by HPLC-UV, volatile compounds by GC/MS, amino acids by LC/MS and minerals by ICP-MS. The results suggested that tea infusions from Zisha and Zhuni pots contain higher levels of EGC, EGCG and total catechins and less caffeine than those from ceramic, glass and plastic pots and tend to have the lowest total mineral contents, potassium and volatile compounds in tea soup. The statistical differences were not all significant among Zisha, Zhuni and stainless steel pots.

CONCLUSION

Based on the overall chemical composition of the tea infusion, Yixing clay pots (Zisha and Zhuni) produce tea infusions that are presumably less bitter and more fragrant and tend to contain more healthful compounds than tea infusions from other pots. The results could partially explain why Yixing clay pots are among the most popular teapots. The beneficial effects of long-term repeated use of these teapots warrants further study. © 2017 Society of Chemical Industry.

Plasma indoxyl sulfate concentration predicts progression of chronic kidney disease in dogs and cats

Indoxyl sulfate is a protein-bound uremic toxin that increases as the severity of impaired renal function increases in humans, laboratory animals, dogs and cats. An elevation of indoxyl sulfate is related to prognosis among people with chronic kidney disease. However, whether indoxyl sulfate is able to predict the progression of chronic kidney disease in dogs and cats has not been previously studied. In the present study, 58 cats and 36 dogs with chronic kidney disease were enrolled. Plasma indoxyl sulfate was measured by high performance liquid chromatography. Renal progression was defined as an increase by one International Renal Interest Society (IRIS) stage and/or a rise in serum creatinine concentration of 0.5mg/dL during the same stage within a 3-month period. Compared with the non-progression groups, across different stages of renal failure, the baseline plasma indoxyl sulfate concentration was increased in the renal progression group (P<0.05), especially for IRIS stages 2 and 3 animals. The area under the receiver operator characteristic curves of indoxyl sulfate, when predicting renal progression, was above 0.75 for both dogs and cats. Indoxyl sulfate concentrations were also correlated with the increase of blood urea nitrogen, serum creatinine, and phosphate and the decrease of hematocrit among cats; while in dogs, concentrations were only correlated with the increase of phosphate concentrations. Indoxyl sulfate served as a biomarker of progression risk in dogs and cats with chronic kidney disease.

The prevalence of Anaplasma platys and a potential novel Anaplasma species exceed that of Ehrlichia canis in asymptomatic dogs and Rhipicephalus sanguineus in Taiwan

Canine anaplasmosis is regarded as an infection by Anaplasma platys rather than zoonotic Anaplasma phagocytophilum in subtropical areas based on the assumption that the common dog tick species is Rhipicephalus sanguineus, which transmits E. canis and presumably A. platys. We investigated asymptomatic dogs and dog ticks from 16 communities in Nantou County, Taiwan to identify common dog tick species and to determine the prevalence of Anaplasma and Ehrlichia spp. Of total 175 canine blood samples and 315 ticks, including 306 R. sanguineus and 9 Haemaphysalis hystricis, 15 dogs and 3 R. sanguineus ticks were positive for E. canis, while 47 dogs and 71 R. sanguineus ticks were positive for A. platys, via nested PCR for 16S rDNA and DNA sequencing of selected positive amplicons. However, among the dogs and ticks that were positive to A. platys 16S rDNA, only 20 dogs and 11 ticks were positive to nested PCR for A. platys groEL gene. These results revealed the importance of searching for novel Anaplasma spp. closely related to A. platys in dogs and ticks. Seropositivity to a commercial immunochromatographic test SNAP 4Dx Anaplasma sp. was not significantly associated with PCR positivity for A. platys but with infestation by ticks carrying A. platys (P<0.05). Accordingly, R. sanguineus may be involved in transmission of A. platys but may not act as a reservoir of E. canis and PCR results for 16S rDNA could be a problematic diagnostic index for A. platys infection.

Prevalence of plasmid-mediated quinolone resistance in Escherichia coli isolated from diseased animals in Taiwan

Escherichia coli (E. coli) is a zoonotic pathogen that often causes diarrhea, respiratory diseases or septicemia in animals. Fluoroquinolones are antimicrobial agents used to treat pathogenic E. coli infections. In this study, 1,221 E. coli strains were isolated between March, 2011 and February, 2014. The results of the antimicrobial susceptibility testing showed a high prevalence of quinolone resistance. The antimicrobial resistance rates of these E. coli isolates to nalidixic acid (NAL) were 72.0% in swine, 81.9% in chickens, 81.0% in turkeys, 64.0% in ducks and 73.2% in geese. Among these isolates, the positive rate for the plasmid-mediated quinolone resistance (PMQR) determinant was 14.8% (181/1,221); the detection rate for qnrS1 was the highest (10.2%), followed by aac(6')-Ib-cr (4.5%) and qnrB2 (0.3%). The quinolone-resistance determining regions (QRDRs) analysis for the PMQR-positive isolates showed that the strains with mutations at codon 83 or 87 in GyrA were resistant to NAL. To the best of our knowledge, this is the first report of occurrence of qnrB2, qnrS1 and aac(6')-Ib-cr genes and high frequency (56.4%; 102/181) of mutation in gyrA or parC among PMQR-positive E. coli strains derived from diseased animals in Taiwan.

Pharmacokinetics and tissue depletion of doxycycline administered at high dosage to broiler chickens via the drinking water

The recommended use of doxycycline (DC) to broiler chicken is 100 mg/L via the drinking water and a 7-day withdrawal time (WDT). However, study of a higher dosage is desirable because of the possible increase of antimicrobial resistance and disease spectrum. Tissue DC residues exceeding the current maximum residue levels (MRL) was our major concern. Therefore, serum concentration and tissue depletion of DC hyclate after administration of 200 mg/L of DC in the drinking water for five consecutive days were studied. The steady-state DC concentration (8.3 ± 0.9 μg/mL) was reached on the third day of medication. The elimination constant (0.05 ± 0.01 1/h), half-life (14.9 ± 1.4 h), area under concentration versus time curve (81.0 ± 9.9 h·μg/mL) and mean residence time (22.7 ± 2.5 h) were obtained using a non-compartmental pharmacokinetic model. It was determined that the current 7-day WDT regulation was still legitimate for the kidney and liver as well as for the breast and leg muscles, which were estimated by linear regression analysis of the 99% upper distribution limit. The unregulated heart and gizzard were considered safe even when the lowest MRL of muscle (100 ng/g) was applied. While at the present time the extra-label use of drugs is only allowed under specific conditions, in the future it may become necessary to increase the general dosage of DC, and the current results suggest a safe range of DC hyclate in chicken; however, skin/fat tissue residues warrant further studies.

Detection of undeclared animal by-products in commercial canine canned foods: Comparative analyses by ELISA and PCR-RFLP coupled with slab gel electrophoresis or capillary gel electrophoresis

BACKGROUND

The potential presence of undeclared animal by-products in pet foods is not subject to routine examination. Previously published methods for species-based identification of animal by-products have not been used routinely owing to inconsistent results. The present study evaluated the utility of several approaches for accurate identification of animal by-products in 11 commercial brands of canine canned foods.

RESULTS

Canine canned foods from several countries were analysed by ELISA, PCR-RFLP coupled with slab-gel electrophoresis (SGE) and capillary gel electrophoresis (CGE) to test for evidence of by-products derived from cattle, chicken, sheep or pig. While CGE-based analysis detected all (24) animal-derived by-products that were reported for the 11 test samples, SGE and ELISA detected only 22/24 (92%) and 14/24 (58%) of labelled by-products, respectively. In addition, undeclared animal by-products were found using all three analytical approaches with CGE detecting more positives (19) than SGE (17) or ELISA (5).

CONCLUSION

Significant disparities were evident between the labelled contents and the detected content of animal by-products. CGE-based testing for PCR products appears to provide greater sensitivity and accuracy than either SGE or ELISA-based methods. As testing of commercial products becomes more reliable and mainstream, manufacturers will need to develop more thorough and accurate labelling protocols.

Florfenicol As a Modulator Enhancing Antimicrobial Activity: Example Using Combination with Thiamphenicol against Pasteurella multocida

Synergistic effects between the same class of antibiotics are rarely reported. Our previous study found synergistic-like interaction between florfenicol (FFC) and thiamphenicol (TAP) against Staphylococcus aureus. Here, the enhanced antimicrobial activity was evaluated in 97 clinical isolates of both Gram-negative and Gram-positive bacteria. Susceptible strains were initially identified by checkerboard microdilution assay (fractional inhibitory concentration index [FICI] ≤ 0.625), followed by confirmation of synergism using the time-kill methodology (≥2 log₁₀ CFU/ml reduction). In all, 43% of Pasteurella multocida tested were susceptible to the enhanced bactericidal effect. In chicken fowl cholera models, FFC and TAP combination at much lower dosage that is correspondent to their MIC deduction provided maximum protection in vivo. Furthermore, synergistic combination of FFC with oxytetracycline (OTC) against Pseudomonas aeruginosa in vitro was also demonstrated. Based on the enhanced uptake of TAP and OTC, FFC presumably elicits enhanced antimicrobial activity in an orderly manner through alteration of bacterial membrane permeability or efflux systems and subsequent increase of intracellular concentration of the antibiotics used in combination. Results of ethidium bromide accumulation assay and RNA-seq showed little evidence for the involvement of efflux pumps in the synergy but further investigation is required. This study suggests the potentiality of a novel combination regimen involving FFC as an initiating modulator effective against both Gram-positive and Gram-negative bacteria depending on the antibiotics that are combined. The observed improvement of bacteriostatic effect to bactericidal, and the extended effectiveness against FFC-resistant bacterial strains warrant further studies.

The Effect and Underlying Mechanism of Ethanol on Intracellular H(+) -Equivalent Membrane Transporters in Human Aorta Smooth Muscle Cells

BACKGROUND

The presence of intracellular pH (pHi ) regulators, including Na(+) -H(+) exchanger (NHE), Na(+) -HCO3- co-transporter (NBC), Cl(-) /OH(-) exchanger (CHE), and Cl(-) /HCO3- exchanger (AE), have been confirmed in many mammalian cells. Alcohol consumption is associated with increased risk of cardiovascular disorder. The aims of the study were to identify the possible transmembrane pHi regulators and to explore the effects of ethanol (EtOH) (10 to 300 mM) on the resting pHi and pHi regulators in human aorta smooth muscle cells (HASMCs).

METHODS

HASMCs were obtained from patients undergoing heart transplant. The pHi was measured by microspectrofluorimetry with the pH-sensitive dye, BCECF-AM.

RESULTS

The following results are obtained. (i) In cultured HASMCs, the resting pHi was 7.19 ± 0.04 and 7.13 ± 0.02 for HEPES- and CO2 /HCO3--buffered solution, respectively. (ii) Two different Na(+) -dependent acid-equivalent extruders, including NHE and Na(+) -coupled HCO3- transporter, functionally coexisted. (iii) Two different Cl(-) -dependent acid loaders (CHE and AE) were functionally identified. (iv) EtOH induced a biphasic, concentration-dependent change in resting pHi (+0.25 pH unit at 100 mM but only +0.05 pH unit at 300 mM) in bicarbonate-buffered solution, while caused a concentration-dependent decrease in resting pHi (-0.06 pH unit at 300 mM) in HEPES-buffered solution. (v) The effect of EtOH on NHE activity was also biphasic: increase of 40% at lower concentration of 10 mM, followed by decrease of 30% at higher concentration of 300 mM. (vi) The increase in Na(+) -coupled HCO3- transporter activity by EtOH was concentration dependent. (vii) The effect of EtOH on CHE and AE activities was both biphasic: increase of ~25% at 30 mM, followed by decrease of 10 to 25% at 100 mM, and finally increase of 15 to 20% at 300 mM.

CONCLUSIONS

This study demonstrated that 2 acid extruders and 2 acid loaders coexisted functionally in HASMCs and that EtOH induced a biphasic, concentration-dependent change in resting pHi by altering the activity of the 2 acid extruders, NHE and Na(+) -coupled HCO3- transporter, and the 2 acid loaders, CHE and AE.

Detection of indoxyl sulfate levels in dogs and cats suffering from naturally occurring kidney diseases

Indoxyl sulfate (IS), a protein-bound uraemic toxin, has been found to accumulate in the serum of people with renal diseases and is associated with free radical induction, nephrotoxicity cardiovascular toxicity, and osteoblast cytotoxicity. Although IS has been studied in humans and in experimental models, the role of IS in dogs and cats with kidney disease has not been investigated. A high performance liquid chromatography system was applied to detect plasma IS concentrations in non-azotaemic animals (63 dogs, 16 cats) and in animals with renal azotaemia (66 dogs, 69 cats). The IS levels of azotaemic animals were significantly higher (P <0.01) than those of non-azotaemic animals (median [IQR] 20.4 (9.5) mg/L vs. 7.2 (8.8) mg/L for dogs; median [IQR] 21 (18.9) mg/L vs. 14.8 (12.3) mg/L for cats). The IS level was significantly correlated with blood urea nitrogen, serum creatinine and phosphate concentrations. Dogs with acute kidney injury had significantly higher IS levels (P <0.01) than those with chronic kidney diseases (CKD) (median [IQR] 57.7 (40.8) mg/L vs. 17.7 (25.1) mg/L). When CKD was graded using the International Renal Interest Society (IRIS) staging system, IS levels were correlated with CKD severity in both dogs and cats. The IS concentration is directly related to loss of renal function. Further studies are necessary to determine whether measurement of IS provides any additional diagnostic or prognostic information in dogs and cats with kidney disease.

Emoghrelin, a unique emodin derivative in Heshouwu, stimulates growth hormone secretion via activation of the ghrelin receptor

ETHNOPHARMACOLOGICAL RELEVANCE

Heshouwu, the root of Polygonum multiflorum, is an anti-aging Chinese traditional medicine. Fresh (raw) Heshouwu is commonly converted to processed Heshouwu by specialized heating to alleviate its side effects of diarrhea presumably caused by anthraquinones. However, raw Heshouwu has been noted to be better than processed Heshouwu regarding anti-aging effects. The therapeutic effects of raw Heshouwu on aging-related diseases were somehow similar to the anti-aging effects of growth hormone release induced by ghrelin

MATERIALS AND METHODS

Major ingredients in the methanol extract from raw Heshouwu were separated and identified. Emodin-8-O-(6'-O-malonyl)-glucoside, a unique anthraquinone glycoside known to be completely eliminated in the conversion process of Heshouwu was isolated. This emodin derivative, tentatively named emoghrelin, was examined for its cytotoxicity and capability of stimulating growth hormone release of rat primary anterior pituitary cells via activation of the ghrelin receptor. Moreover, molecular modeling of emoghrelin docking to the ghrelin receptor was exhibited to explore the possible interaction within the binding pocket.

RESULTS

No apparent cytotoxicity was observed for emoghrelin of 10(-7)-10(-4)M. Similar to growth hormone-releasing hormone-6 (GHRP-6), a synthetic analog of ghrelin, emoghrelin was demonstrated to stimulate growth hormone secretion of rat primary anterior pituitary cells in a dose dependent manner, and the stimulation was inhibited by [d-Arg(1), d-Phe(5), d-Trp(7,9), Leu(11)]-substance P, an antagonist of the ghrelin receptor. Molecular modeling and docking showed that emoghrelin as well as GHRP-6 could fit in and adequately interact with the binding pocket of the ghrelin receptor.

CONCLUSION

The results suggest that emoghrelin is a key ingredient accounting for the anti-aging effects of Heshouwu, and possesses great potential to be a promising non-peptidyl analog of ghrelin.

Associations between serum total bilirubin levels and functional dependence in the elderly

BACKGROUND

Many studies support the role of bilirubin as a cytoprotector in chronic inflammatory diseases, such as stroke and atherosclerosis.

AIM

To investigate the relationship between serum total bilirubin levels and functional dependence in older adults.

METHODS

Data from the National Health and Nutrition Examination Survey (1999-2002) pertaining to 2235 old adults were analysed. All participants had given a household interview, providing information of five major domains on self-reported functional status (activities of daily living, instrumental activities of daily living, leisure and social activities, lower extremity mobility and general physical activities), had completed serum total bilirubin measurement, and a questionnaire regarding personal health. Poor performance was defined as experiencing difficulty with one or more items in a given domain. Functional dependence was defined as having three or more poor performances in the five major domains. Multiple logistic regression was performed together with quartile-based stratified odds ratio (OR) comparison and trend tests.

RESULTS

The OR of functional dependence for each standard deviation increment in the serum total bilirubin level was 0.56 (P = 0.002). After additional adjustment, the inverse association remained essentially unchanged. In quartile-based analysis, participants with higher quartiles of serum total bilirubin tended to have lower ORs of functional dependence. The trends of lower likelihood of functional dependence across increasing quartiles of the serum total bilirubin level were statistically significant (P < 0.05 for all trends).

CONCLUSIONS

Higher serum total bilirubin levels were associated with lower likelihood of functional dependence in older adults.

Liquid chromatography incorporating ultraviolet and electrochemical analyses for dual detection of zeranol and zearalenone metabolites in mouldy grains

BACKGROUND

Zeranol (Z) is a semi-synthetic mycotoxin that is used in some countries as a growth-promoting agent in livestock. In view of the known oestrogenic actions by Z and certain Z analogues, significant concerns exist with regard to the presence of Z residues in human foods and the potential for untoward effects, including carcinogenicity within the reproductive system. In order to confirm that foods are free from harmful Z residues, regulators need a quick and reliable analytical method that can be used for routine confirmation of Z-positive samples identified by enzyme-linked immunosorbent assay (ELISA) screening. In this study the authors have developed and validated a simple and rapid high-performance liquid chromatography method incorporating ultraviolet (UV) absorbance (wavelength 274 nm) and electrochemical (EC) dual-mode detection for simultaneous determination of Z-related mycotoxins produced from mouldy grain matrices, including rice, soybean and corn flakes.

RESULTS

Recoveries for all analytes were around 80% and the limits of detection ranged from 10 to 25 ng mL(-1) for UV and from 50 to 90 ng mL(-1) for EC detection with good accuracy and reproducibility. Differential profiles and occurrence rates of Z, β-zearalenol, β-zearalanol and α-zearalenol in naturally moulded grain matrices were observed, indicating different metabolite patterns and possibly grain-specific effects of mycotoxin exposure for humans and animals. The strength of this dual detection method lies in its selectivity characterised by a carbon screen-printed electrode such that aflatoxin interference is precluded.

CONCLUSION

The combined dual detection technique affords quick and reliable semi-confirmative and quantitative information on multiple types of Z analogues in mouldy grains without the necessity of using expensive mass spectrometry. The method is considered a superior supplement to ELISA, which only screens total Z immunoreactivity.

Genetic analysis of fish iridoviruses isolated in Taiwan during 2001-2009

To investigate the genetic relationships between field strains of iridoviruses gathered from various fish species in Taiwan, viruses that were collected from 2001 to 2009 were analyzed. Open reading frames encoding the viral major capsid protein (MCP) and adenosine triphosphatase (ATPase) were sequenced for phylogenetic analysis. Our results indicated that iridoviruses from Taiwan aquaculture fishes could be classified into two groups: prior to 2005, the viruses were closely related to members of the genus Ranavirus; and after 2005, they were similar to members of the genus Megalocytivirus. Based on the analysis of MCP amino acid sequences, virus isolates were divided into 4 major genotypes that were related to ISKNV, RSIV, FLIV, and GIV, respectively. Pairwise comparisons of MCP genes showed that the ranavirus was an epidemic pathogen for economically important species in the major production regions and cultured marine fish, while the megalocytivirus isolates were sensitive to host range. In addition, the distribution of synonymous and non-synonymous changes in the MCP gene revealed that the iridoviruses were evolving slowly, and most of the variations were synonymous mutations. The Ka/Ks values were lower than one, and hence, the viruses were under negative selection.

Implication of light sources and microbial activities on degradation of sulfonamides in water and sediment from a marine shrimp pond

In this study, the effects of natural, visible and ultraviolet lights, microbial activities and aerobic and anaerobic conditions on degradation of four different sulfonamide antibiotics (SAs) were studied. Water and sediment collected from a marine shrimp pond were examined and a factorial design was employed to evaluate the effects of selected parameters. The results showed that all the SAs in water and sediment had significant declines attributed to natural light and microbial activities. The half-lives (t(1/2s)) of SAs in non-sterile water and sediment samples under natural light were 2.0-15.0 and 0.7-7.3 days, respectively, and slowed to 2.9-62.9 and 6.9-85.6 days after sterilized. Moreover, the declines of SAs were significantly faster under ultraviolet than visible light with 36.5-70.9% shorter t(1/2)s. Anaerobic condition was also effective on declines of SAs in sediment. Both sulfate-reducing and methanogenic microbes were directly involved in the decline of SDM, and indirectly contributed to SMX declines.

Differential heat stability of amphenicols characterized by structural degradation, mass spectrometry and antimicrobial activity

Heat stability of amphenicols and the relationship between structural degradation and antimicrobial activity after heating has not been well investigated. Florfenicol (FF), thiamphenicol (TAP), and chloramphenicol (CAP) were heated at 100 degrees C in water, salt water, soybean sauce and chicken meat for up to 2h. Degradation and antimicrobial activity of the compounds was evaluated using capillary electrophoresis (CE) with UV-DAD spectrometry, minimum inhibitory concentration (MIC) assay, and gas chromatography with electron impact ionization mass spectrometry (GC-EI-MS). Heat stability of amphenicols in matrices was ranked as water> or =salt water>soybean sauce>meat, suggesting that heat degradation of amphenicols was accelerated in soybean sauce and was not protected in meat. Heat stability by drug and matrices was ranked as FF>TAP=CAP in water, FF=TAP>CAP in salt water, TAP> or =FF=CAP in soybean sauce, and TAP> or =FF=CAP in meat, indicating differential heat stability of amphenicols among the 3 drugs and in different matrices. In accordance with the less than 20% degradation, the MIC against Escherichia coli and Staphylococcus aureus did not change after 2h heating in water. A 5-min heating of amphenicols in water by microwave oven generated comparable percentage degradation to boiling in water bath for 30 min to 1h. Both CE and GC-MS analysis showed that heating of FF produced TAP but not FF amine as one of its breakdown products. In conclusion, despite close similarity in structure; amphenicols exhibited differential behavior toward heating degradation in solutions and protein matrices. Although higher degradations of amphenicols were observed in soybean sauce and meat, heating treatment may generate product with antimicrobial activity (FF to TAP), therefore, heating of amphenicol residues in food cannot always be assumed safe.