Search Results (4)

Objective: This study aimed to develop a robust multi-residue analytical method for the precise identification and quantification of six macrolide antiparasitic agents commonly used in animal husbandry feeds. Method: Feed samples were extracted using a water-saturated acetonitrile solution. The resulting crude extracts were then treated with n-hexane and further purified by HLB solid-phase extraction columns to obtain the test solutions. These prepared samples were analyzed by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The method was validated across six different feed matrices, including pig premix, concentrate, and complete feed, as well as chicken premix, concentrate, and compound feed. The method exhibited average recoveries ranging from 80.07% to 98.80%. The intra-day coefficients of variation (CV) for the first three feed types ranged from 1.98% to 12.84%, while for the latter three, the CVs ranged from 2.43% to 13.69%. Results: The method’s precision led to the quantification limit of avermectin, doramectin, acetyl avermectin, and ivermectin being 25 μg/kg, whereas for moxifloxacin and milbemycin, the limit was 50 μg/kg. These thresholds meet the stringent requirements for trace drug analysis, supporting the method’s suitability for regulatory surveillance and monitoring of these specified antibiotics in animal feeds. Full article

Evaluating different tactics to mitigate the effects of gastrointestinal nematode infection in growing stocker cattle is essential to better understand opportunities to optimize cattle health and performance. Due to the potential development of anthelmintic resistance, parasitologists and industry stakeholders have proposed maintaining refugia in cattle populations and combination treatment as tactics to delay anthelmintic resistance yet limited large-scale field data are available for practitioners to make evidence-based decisions. The objective of this experiment was to compare the effects of extended-release eprinomectin injectable and doramectin injectable on growth and fecal shedding of parasites in stocker calves grazing with non-treated (refugia) cohorts. Steers (n = 995; 243.38 kg) were randomized to one of two experimental treatment groups on Day 0, extended-release eprinomectin (ERE) or doramectin injectable (DOR). A subset of animals (n = 47) was selectively not treated with an anthelmintic to maintain refugia (REF). Individual body weights were recorded on days 0, 105, and 130 to calculate average daily gain and overall body weight gain during each of those time periods. Fecal samples were collected per rectum from approximately 10% of the same animals in each group on days 0, 105, and 130. Mean fecal egg count was significantly lower in the 10% of animals tested in the ERE group on days 105 and 130 when compared to 10% of the animals in the DOR group (Day 105—ERE: 46.45 eggs per gram, DOR: 155.30 eggs per gram, p < 0.01; Day 130—ERE: 9.65 eggs per gram, DOR: 22.51 eggs per gram, p = 0.02). From day 0 to 105, the mean average daily gain in the ERE group was 0.87 kg/day, which tended (p = 0.055) to be higher than the mean for the DOR group, 0.845 kg/day. Full article

Cholangiocarcinoma is a malignant tumor that emerges in the intrahepatic or extrahepatic bile ducts. Doramectin (DOR), a third-generation derivative of avermectins (AVMs), is renowned for its low toxicity and high efficiency. However, no research has hitherto focused on the anti-cholangiocarcinoma effects of these drugs. In this study, we undertook a preliminary exploration of the mechanism through which DOR inhibits the viability of human cholangiocarcinoma cells (Mz-ChA-1) via transcriptome analysis and molecular validation at the cellular level. The results indicated that DOR could suppress the growth and proliferation of Mz-ChA-1 cells in a dose-dependent manner. Moreover, it significantly diminished their migration and invasion abilities. Cell cycle analysis disclosed arrest in the G1 phase, accompanied by an increase in p21 expression and a decrease in the levels of the cyclin E1 and CDK2 proteins. Additionally, DOR induced apoptosis via the ROS-triggered mitochondrial pathway. This was attested by an elevation in the BAX/BCL-2 ratio, the activation of caspase 3/7 and the cleavage of PARP1. These mechanistic insights underscore DOR’s potential as a therapeutic agent against cholangiocarcinoma Full article

In this study, a fast, concise and reliable ultra-high performance liquid chromatography-fluorescence (UHPLC/FLD) detection method for simultaneous quantification of avermectins (AVMs), including avermectin (AVM), ivermectin (IVM), emamectin (EMM), moxidectin (MOX) and doramectin (DOR) in six aquatic foods was established. Based on the QuEChERS pretreatment method, the samples were extracted with 0.2% (v/v) ammonia acetonitrile. N-methyl imidazole mixed with acetonitrile (1:1, v/v) and trifluoroacetic anhydride with acetonitrile (1:2, v/v) were used as derivatization reagents. The mobile phase consists of acetonitrile and water with a flow rate of 1.0 mL/min. An Infinity Lab Poroshell 120 EC-C18 column was used for optimum chromatographic separation of target analytes at 40 °C; the excitation and emission wavelengths were set at 365 nm and 465 nm, respectively. In six kinds of aquatic foods, the limits of detection (LODs) of AVM, IVM, EMM, MOX, and DOR were 2.7 μg/kg, 1.8 μg/kg, 2.1 μg/kg, 1.2 μg/kg, and 2.7 μg/kg, respectively, and the limits of quantification (LOQs) of AVM, IVM, EMM, MOX, and DOR were 5 μg/kg, 4.5 μg/kg, 4.5 μg/kg, 3.5 μg/kg and 5.0 μg/kg, respectively. The recoveries were all above 85.38% when the samples were spiked with the target compounds at the concentration level of 5, 10, 50, and 100 μg/kg. The intra-day and inter-day relative standard deviations (RSDs) were all less than 15%. This method considers the requirements of sensitivity, accuracy, and economics of the instrument. Full article