This study was conducted to reset the maximum residue limit (MRL) for didecyldimethylammonium chloride (DDAC) in broiler chickens. The disinfectant containing DDAC (10%, w/w) was diluted 160 times and evenly sprayed on the bodies of twenty-four broiler chickens at a rate of 15 mL per day per bird for 7 days. After the disinfectant treatment, tissue samples were collected from six broiler chickens at 0.25, 1, 3 and 5 days, respectively. Residual DDAC concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 2.0~10.0 μg/kg), recoveries (86.9~118.6%), and coefficient of variations (<19.98%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In all tissues except for liver, DDAC was detected more than LOQ at 5 days after the disinfectant treatment. In liver tissues, DDAC was detected more than LOQ at 3 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal period of DDAC in poultry tissues was established to 26 days. In conclusion, the developed analytical method is sensitive and reliable for detecting DDAC in poultry tissues. When DDAC disinfectant is sprayed on a poultry house in the presence of broiler chickens, it is necessary to keep the disinfectant from contacting the body of the livestock.

This study evaluated the fungicidal efficacy of weakly acidic hypochlorous acid water (WAHW) against Microsporum canis (M. canis) and its therapeutic effect on M. canis-infected mouse skin. WAHW was produced by a WAHW generation module. A fungicidal efficacy test by the broth dilution method was used to determine the lowest effective concentration of the WAHW. The lowest effective concentration of WAHW was less than 10 ppm. For T-1, T-2, and T-3, 30 ppm of WAHW was applied to the infected skin once, twice, and three times a day, respectively, and for T-4, 50 ppm of WAHW was applied once a day. On the 3rd day after the initiation of treatment, skin scores in all of the WAHW-treated groups were significantly decreased compared to those in the positive control group (PC) (p<0.05), and there were no significant differences compared to the normal control (NC). The area of the infected skin in all of the WAHW-treated groups was significantly decreased compared to PC from the first day after the initiation of WAHW treatment (p<0.05). The results showed that WAHW had a fungicidal efficacy on M. canis at less than 10 ppm, and it was effective in improving skin symptoms when 30 ppm of WAHW was applied to the M. canis-infected area once a day for five days or 50 ppm of WAHW was applied once a day.

This study investigated ethopabate (EPB) residues in edible tissues of broiler chickens given in drinking water and established the withdrawal time (WT) of EPB in poultry tissues. Twenty-four healthy Ross broiler chickens were orally administered with EPB at the concentration of 3.8 mg/L for 14 days (EPB-1, n=24) and 15.2 mg/L for 7 days (EPB-2, n=24) through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3, and 5 days, respectively. EPB residue concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient values ranged from 0.9980 to 0.9998, and the limits of detection and quantification (LOQ) were 0.03~0.09 and 0.1~0.3 μg/kg, respectively. Mean recoveries in muscle, liver, kidney and skin/fat tissues were 95.9~109.8, 108.7~115.3, 89.9~96.6 and 86.7~96.8%, respectively, and coefficient of variations were less than 17.11%. At the end of the drug-administration period (0 day), EPB was detected at levels under the LOQ in all tissues from both the EPB-1 and EPB-2 groups. According to the results of EPB residue in Ross broiler tissues, withdrawal periods of both EPB-1 and EPB-2 in poultry tissues were established to 0 day. In conclusion, the developed analytical method is suitable for the detection of EPB in poultry tissues, and the estimated WT of EPB in poultry tissues will contribute to ensuring the safety of Ross broiler chickens.

From 2020, Korean Animal and Plant Quarantine Agency has reset the withdrawal time (WT) for veterinary drugs typically used in livestock in preparation for the introduction of positive list system (PLS) program in 2024. This study was conducted to reset the MRL for amprolium (APL) in broiler chickens as a part of PLS program introduction. Forty-eight healthy Ross broiler chickens were orally administered with APL at the concentration of 60 mg/L (APL-1, n=24) for 14 days and 240 mg/L (APL-2, n=24) for 7 days through drinking water, respectively. After the drug treatment, tissue samples were collected from six broiler chickens at 0, 1, 3 and 5 days, respectively. Residual APL concentrations in poultry tissues were determined using LC-MS/MS. Correlation coefficient (0.99 >), the limits quantification (LOQ, 0.3~5.0 μg/kg), recoveries (81.5~112.4%), and coefficient of variations (<15.5%) were satisfied the validation criteria of Korean Ministry of Food and Drug Safety. In APL-1, APL in all tissues except for kidney was detected less than LOQ at 3 days after drug treatment. In APL-2, APL in liver and kidney was detected more than LOQ at 5 days after treatment. According to the European Medicines Agency’s guideline on determination of withdrawal periods, withdrawal periods of APL-1 and APL-2 in poultry tissues were established to 3 and 2 days, respectively. In conclusion, the developed analytical method is sensitive and reliable for detecting APL in poultry tissues. The estimated WT of APL in poultry tissues is longer than the current WT recommendation of 2 days for APL in broiler chickens.

This study examined the subacute oral toxicity of Dendropanax morbiferus H.Lév leaves hot-water extracts (DMWE) using male and female Spargue-Dawley rats. Rats were orally administered the DMWE at dose levels of 0, 250, 500, 1,000, and 2,000 mg/kg body weight (BW) for four weeks. For experimental period, clinical signs and the number of deaths were examined, and feed intake and BW of all experimental animals were measured once a week for four weeks. At the end of the experiment, blood samples were collected from all rats, and all animals were euthanized and autopsies were performed to collect major organs. No dead animals were found during the experimental period. In addition, no differences were found between control and DMWE-treated groups in feed intakes, BW changes, organ weights, clinical signs, hematological parameters, and serum biochemical parameters. The results of this study provided evidence that oral administration of DMWE at the dose of 2,000 mg/kg BW is safe in rats and may not exert severe toxic effects.

In this study, the acute toxicity of Dendropanax morbiferus H.Lév leaf hot-water extracts (DMWE) was examined in male and female ICR mice. Mice were orally administered the DMWE at dose levels of 0, 250, 500, 1,000 and 2,000 mg/kg body weight (BW) for single-dose toxicity test. There were no significant differences in change of BW between control and all DMWE treated-groups. In hematological and blood biochemical analysis, none of the parameters were affected by the DMWE. Similarly, there were no significant effects on markers for liver and kidney functions in all DMWE treated-groups. Since there were no adverse effects of the DMWE in single oral toxicity tests, even at the highest doses, it was concluded that the lethal dose 50 (LD50) of DMWE is estimated at > 2,000 mg/kg BW.

This study evaluated the effect of a combination of acetaminophen (AAP), vitamin C (VC) and thioctic acid (TA) on reducing serum cortisol concentrations in mice with foot-and-mouth disease (FMD) vaccination. For 5 days from 3 days before FMD vaccination to 2 days after vaccination, mice were orally administered with AAP 600 mg/kg feed (n=25, AAPT), combination of AAP 600 mg and VC 200 mg per kg feed (n=25, AVCT) and combination of AAP 600 mg, VC 200 mg and TA 20 mg per kg feed (n=25, AVTT), respectively. From day 1 to day 7 after FMD vaccination, the cortisol concentration of all groups treated with the drug was significantly decreased compared to that of the positive control group with FMD vaccination (p<0.05). In conclusion, the combined treatment of AAP, VC and TA was the most effective in relieving stress from FMD vaccination compared to the single treatment.

This study investigated changes of milk production in dairy cows intramuscularly injected with drugs containing dexamethasone (DXM). Three types of dexamethasone formulations (Bueunde® (DXM 0.5 mg/mL), Dexason INJ.® (DXM 1 mg/mL) and Dexolone-20 inj.® (DXM 1 mg/mL)) were intramuscularly injected into sixteen healthy dairy cows each. Bueunde® was intramuscularly injected into 8 dairy cows with 5 mg (BED-1) and 10 mg (BED-2) of DXM once a day for 3 consecutive days, respectively. Dexason INJ.® was intramuscularly administered once into dairy cows with 20 mg (DXS-1, n=8) and 40 mg (DXS-2, n=8) of DXM, respectively. Dexolone-20 inj.® was intramuscularly injected once into dairy cows with 20 mg (DXS-1, n=8) and 40 mg (DXS-2, n=8) of DXM, respectively. Milk production (MP) of BED-1 and BED-2 significantly decreased during the drug administration and up to 48-hour post-drug treatment. Compared with the MP before drug administration, the MP of DXS-1 and DXL-1 was meaningfully decreased by 36 and 24-hour post-drug administration, respectively, and that in both DXS-2 and DXL-2 significantly decreased until 48-hour post-drug treatment. In conclusion, it was confirmed that the MP temporarily decreased by 48 hours after administration of DXM to dairy cows.

Based on many previous studies, this study reviewed the effects of needle-free intradermal injection (NFI) on the prevention of the incidence of lesions at the injection site in pork from pigs vaccinated with the foot-and-mouth disease vaccine, the reduction of the vaccine dose, the stress-relief of vaccination, and the reduction of farm worker-related injuries. The vaccine and drugs injected with the NFI pass through the tissue and are widely dispersed along the path of least resistance, resulting in a vastly dispersed, spider-web-like distribution of the medication and absorbed quickly. In addition, since NFI is inoculated into the dermal layer where immune cells are abundantly distributed, even a small amount of vaccination shows an antibody-forming effect similar to that of the conventional needle intramuscular injection. NFI is a method suitable for animal welfare because the vaccine or drug is widely dispersed over the inoculation site and causes less pain or stress than the needle intramuscular injection. Use of NFI system for the vaccination and drug delivery improves work efficiency in farms and reduces the incidence of musculoskeletal disorders in farm workers. In the future, it is judged that in-depth studies are needed on the effect of improving productivity and reducing the dose of antibiotics through NFI.

This study investigated chlorpheniramine maleate (CPM) residues in milk of intramuscularly dosed dairy cows and established the withdrawal time (WT) of CPM in milk. Sixteen healthy Holstein cows were injected with 10 (CPM-1) and 20 mL (CPM-2) of the drug containing 4 mg/mL of CPM, respectively. After administration of CPM, milk samples were collected from all cows at 12 hour intervals for 5 days. CPM residue concentrations in milk were determined using LC-MS/MS. The correlation coefficient of the calibration curve was 0.9956, and the limits of detection and quantification (LOQ) were 0.6 and 1.0 μg/kg, respectively. Recoveries ranged between 98.5-115.0%, and coefficient of variations were less than 10.96%. After treatment, CPM in CPM-1 and CPM-2 was detected below the LOQ in all milk samples at 12 hours. According to the European Medicines Agency’s guideline on determination of withdrawal periods for milk, withdrawal periods of both CPM-1 and CPM-2 in milk were established to 12 hours. In conclusion, the developed analytical method is sensitive and reliable for detection of CPM in milk, and the estimated WT of CPM in bovine milk will contribute to ensuring the safety of milk.

A number of studies have been conducted to confirm the preventive effect of xylitol on dental caries as a whole or partial alternative to dietary sugars. This study reviewed the oral health effects of xylitol on the prevention mechanism of dental caries, the prevention of dental caries, the inhibition of mother-to-child transmission, and the oral health effects in the elderly based on existing studies on the oral health of xylitol. Carbohydrates and dietary sugars in food are fermented by acid-producing microorganisms in the mouth and produce dental plaque and acid, which cause dental caries. However, most dental decay-causing bacteria cannot produce acids by metabolizing xylitol. Xylitol, stored in cells as a non-metabolizable metabolite by Streptococcus mutans (S. mutans), affects bacterial glucose metabolism and inhibits bacterial growth. Xylitol consumption also reduces the amount of plaque and the population of S. mutans in both plaque and saliva. In addition, xylitol acts in the remineralization process. Xylitol has been confirmed to effectively prevent dental caries, inhibit mother-to-child transmission of MS, prevent dental caries, and increase salivary flow in the elderly. In conclusion, xylitol is an adequate sugar substitute for dental health, from infants to the elderly. For future studies, the researchers recommend reviewing the effects of xylitol on the oral and intestinal microbial environment and the side effects of excessive intake.

The present study is designed to investigate the antibacterial effect of the hot-water and various ethanol extracts from the leaves of Dendropanax morbifera L. (DML) against Porphyromonas gingivalis (P. gingivalsis). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of 30, 50 and 70% ethanol extract of DML against P. gingivalis decreased in a concentration-dependent manner. However, MIC and MBC of hot-water and 30% ethanol extract against P. gingivalis were the same as 3.13 and 6.25 mg/mL, respectively. In the bacterial growth inhibition test, the growth of P. gingivalis in the group treated with MBC and 2×MBC of DML hot-water extract was statistically significantly decreased from 6 h after incubation compared to the control group (p<0.001). From the results portrayed above, aqueous extract from DML at the concentration of 6.25 mg/mL can be usefully used to suppress infection of P. gingivalis, a major causative agent of periodontal disease.

This study compared the immune responses, stress relief and weight gains of needle or needle-free intramuscular and needle-free intradermal vaccination in pigs. When the same amount of a foot-and-mouth disease (FMD) vaccine was administered to pigs, antibody titers at 4 weeks after the 1st and 2nd FMD vaccination were not significantly different between the needle (IM-S) and needle-free (NM-P250) intramuscularly vaccinated groups, but the weight gain of NM-P250 was significantly increased compared to that of IM-S at 8 weeks after the 2nd FMD vaccination (p<0.05). In addition, serum cortisol concentrations of NM-P250 were considerably decreased compared to those of IM-S on the 5th and 7th day after the 1st and 2nd FMD vaccination (p<0.05). However, the antibody titers of IM-S vaccinated with 2 mL of FMD vaccine were significantly increased compared to those of the needle-free intradermal vaccinated group with 0.5 mL of FMD vaccine at 4 weeks after the 1st and 2nd FMD vaccination (p<0.05). In conclusion, the needle-free intramuscular injection for the FMD vaccination can be chosen for weight gain and stress relief in pigs.

The present study is designed to investigate the hypolipidemic effect of the hot-water extract from the leaves of Dendropanax morbifera L. (DMWE) in hyperlipidemic rats. Thirty male 5-week-old rats were grouped as follows: Normal control (NC) given distilled water; hyperlipidemic control (HC) administered with distilled water; drug treatment (DT) orally administered with atorvastatin (10 mg/kg body weight (BW)); DMWE-treated groups (DM-50, DM-100 and DM-200) treated with DMWE 50, 100 and 200 mg/kg BW, respectively. All groups (except for NC) were fed a high-fat diet during the experiment. After 4 weeks of administration, the BW of all groups treated with DMWEs significantly increased compared to that of HC (p<0.05) and showed no significant difference compared to that of NC. In addition, serum total cholesterol levels in all groups treated with DMWEs were meaningfully decreased, compared to that in HC (p<0.05). In serum triglyceride (TG) and low-density lipoprotein-cholesterol levels, both DM-100 and DM-200 considerably decreased compared to HC (p<0.05), and no significant differences in TG levels were between DM-100 and DM-200. In high-density lipoprotein-cholesterol levels, DM-200 was statistically different compared to HC, and there were no significant differences between DM-100, DM-200 and DT. Furthermore, aspartate transaminase and alanine aminotransferase concentrations of DM-100 and DM-200 were significantly decreased compared to those of HC (p<0.05). From results portrayed above, DMWE at the concentration of 100 mg/kg BW has been identified to be effective in the treatment of hyperlipidemic rats.

This study investigated the preventive effect of Dendropanax morbifera leaf extracts (DMLEs) drew out with water, 30, 50 and 70% ethanol against alcohol-induced hepatotoxicity in vitro and vivo. The 3-(4,5-dimethylthiazol-2-yl)-2,5-dipenyltetrazolium bromide (MTT) assay was performed to assess cytotoxic activity of DMLEs, and the half-maximal inhibitory concentration (IC50) ranged between 1.11 and 2.08 mg/mL on Hep3B cells. In preventing ethanol-induced-hepatotoxicity on Hep3B cells, 30 and 50% ethanol DMLEs were significantly effective compared to the 5% ethanol treatment control. In addition, the 30% ethanol DMLE was orally provided to rats 30 min prior to the administration of ethanol (3 mL/kg body weight). At 1, 3 and 5 h after ethanol treatment, the plasma levels of ethanol and acetaldehyde were determined. The 30% ethanol DMLE effectively decreased the plasma ethanol levels during 5 h but increased the plasma acetaldehyde levels until 3 h and then significantly decreased at 5 h, as compared to the control. These results indicate that the 30% ethanol DMLE possesses a potent preventive effect against ethanol-induced liver toxicity in Sprague-Dawley rats.

Aspergillus flavus (A. flavus) and Aspergillus fumigatus (A. fumigatus) are the main fungi that cause stonebrood in honey bees. Additionally, these fungi cause the declines of honey bee population and the economic loss in the beekeeping industry. In this study, the efficacy of a disinfectant, composed to chlorine dioxide (10%, w/v) and quaternary ammonium compound (12.5%, w/v), was evaluated against A. flavus and A. fumigatus. A fungicidal efficacy test by broth dilution method was used to determine the lowest effective dilution of the disinfectant following exposure to test fungi for 30 min at 4°C. The disinfectant and test fungi were diluted with low and high organic matter (OM) suspension according to treatment condition. On low OM condition, the fungicidal activity of the disinfectant against A. flavus and A. fumigatus was all 2.0 fold dilutions. On high OM condition, the fungicidal activity of the disinfectant against A. flavus and A. fumigatus was all 1.25 fold dilutions. The recommended dilution ratio of the disinfectant in low and high OM was 1.6 and 1.0 fold dilution, respectively. As the disinfectant possesses fungicidal efficacy against A. flavus and A. fumigatus, the disinfectant can be used to prevent the stonebrood in honey bees.

A progressive muscle atrophy is strongly associated with aging, resulting in lower quality of life in elderly individuals. This study was conducted to determine relative hemoglobin (Hb) concentrations in the rabbit model of the sciatic nerve transection injury using non-invasive diffuse optical spectroscopy (DOS). From the 2nd week to the end of the experiment after sciatic nerve injury, a total muscle mass in nerve injured-group (NI group) significantly reduced compared with that in the normal group (p<0.001). During the capillary occlusion after nerve injury, the deoxy-hemoglobin (Hb-R) concentration in NI group significantly increased compared to that in the normal group at the 2nd and 3rd week after sciatic nerve injury (p<0.05). During the capillary release after nerve injury, the oxy-hemoglobin (Hb-O2) concentration in NI group significantly decreased at the 1st and 3rd week, and Hb-R significantly increased at 2nd week, compared to those in the normal group (p<0.05). Histological changes in the gastrocnemius muscle of NI group observed that clear fat filled spaces at the periphery of muscle fibers and angular fibers. From the results of this study, non-invasive DOS could be used to measure changes of Hb concentrations in muscles.

본 연구는 닭 진드기 구제를 목적으로 개발된 살비제인 와구잡이 II® (WGJB, 편백정유 : 계피정유 = 20 : 56)에 대하여 토끼와 기니픽을 이용하여 피부 자극성 및 감작성 평가를 각각 수행하였다. 일차피부자극시험에서 토끼의 피부에 WGJB를 24시간 동안 처리한 후 피부 자극성을 확인한 결과, WGJB는 비찰과 부위에서 홍반과 부종과 같은 어떠한 부작용도 일으키지 않았으나, 몇몇 토끼의 찰과 부위에서 매우 약한 홍반과 부종을 나타내어 WGJB의 1차 피부자극 지수는 0.625이었다. 따라서 WGJB는 약한 자극성이 있는 물질로 분류되었다. 피부감작성 시험에서 기니픽에 0.1 mL의 WGJB을 피내주사한 후 24시간 동안 감작시켰다. 감작 1주일 후 WGJB를 함유한 패취를 주사 부위에 부착하여 48시간 동안 처리한 다음, 2주 후에 WGJB 를 함유한 패취를 부착하여 감작을 야기시켰다. WGJB는 어떠한 알러지 반응도 나타내지 않았다. 따라서, 본 연구를 통하여 WGJB는 약한 피부 자극성을 가지며 감작성을 야기하지 않는 물질로 평가되었다.

This study investigated the residue of tulathromycin (TLM) on the lung tissue of pigs intramuscularly injected with 2.5 mg/kg body weight as a single dose. Nine healthy cross swine were intramuscularly injected with the drug. Three treated animals were arbitrarily selected to be sacrificed at 7, 10 and 14 days after treatment. TLM residue concentrations in lung tissue were determined using liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS). The drug was extracted from lung samples using acetonitrile followed by clean-up with n-hexane. The analyte was separated on a Hypersil GOLDTM liquid chromatography column using 0.1% formic acid in deionized distilled water and acetonitrile. The correlation coefficient (R2) of the calibration curve was 0.9981, and the limits of detection and quantification were 10 and 50 μg/kg, respectively. Recoveries at three spiking levels ranged between 95.0-98.2%, and relative standard deviations were less than 3.95%. In TLM-treated group, the concentration of TLM on 7, 10 and 14 days post-treatment was 627.3, 496.9, 259.1 μg/kg, respectively. The developed method is sensitive and reliable for detection of TLM in porcine lung tissues. In addition, it can detect below the maximum residue limits in animal-derived food products destined for human consumption.

This study was to evaluate the skin sensitization of potassium hydroxide (KOH) by the guinea pig maximization test. In the preliminary test, the induction and challenge dose of KOH were determined as 1.0 and 0.2%, respectively. Guinea pigs were sensitized with intradermal injection of 0.1ml KOH for 24 h. After 1 week, 1.0% of KOH was treated on the site of injection and 0.2% of KOH was challenged 2 weeks later. The average skin reaction evaluated by erythema and edema on the challenge sites and sensitization rate in the KOH-treatment group at 24 h were 0.0 and 0%, respectively, which are substantially low compared with in the 2,4-dinitrochlorobenzene-treatment group (positive control group) (average skin reaction: 3.0, sensitization rate: 100%) and identical with in the distilled water-treatment group (negative control group), representing a weak sensitizing potential. The average skin reaction and sensitization rate observed at 48 h were 0.0 and 0% in the KOH-treatment group, respectively, and 2.0 and 100% in the positive control group, respectively. It was concluded that 1.0% of KOH classified to Grade I, induced no sensitization when tested in guinea pigs.