Oxolinic acid (OA) is a widely recommended antimicrobial agent for managing Gram-negative bacterial infections in aquaculture. This study investigates the pharmacokinetics and withdrawal period of OA in Trachinotus blochii, a high-value mariculture species, under tropical conditions. A single oral dose of 12 mg/kg was administered, and OA levels were quantified using Liquid Chromatography-Tandem Mass Spectrometry across 12 time points from plasma, intestine, liver, kidney, and gills. Maximum concentrations (Cmax) were reached within 6 h (Tmax). Cmax (μg/Kg) followed the order: plasma (99.77) < liver (666.67) < intestine (1764.67) = gill (1776.67) = kidney (1783.33). The elimination half-life (T½) was longest in the kidney, followed by the liver and intestine, whereas plasma and gills exhibited faster elimination. Tissue/plasma ratios were 4.6 (liver), 8.4 (gill), 13.95 (kidney), and 17.12 (intestine). The results demonstrated that OA was rapidly absorbed from the intestine, distributed extensively, and eliminated quickly through renal, intestinal, and branchial routes. The kidney played a key role in OA elimination. In the withdrawal study, after 7 days of in-feed administration at the therapeutic dose, OA exceeded the recommended maximum residue limit in edible tissues at 6 h. The drug levels dropped below detectable limits within 24 h. Applying a 30% safety margin, a withdrawal period of 31.2 h (or 37.7°C- days) is recommended. The findings provide a practical framework for the responsible and effective use of OA in T. blochii mariculture, promoting aquaculture sustainability and food safety.

The emergence of beta-lactamase producing multidrug-resistant (MDR) gram-negative bacteria presents a significant challenge to effective treatment of infections. This study focuses on the isolation, amplification, and molecular characterization of β-lactamase genes from clinical strains of Escherichia coli and Klebsiella pneumoniae. Seven new partial gene sequences, including novel variants of blaOXA and blaNDM, were identified after screening 108 clinical samples and submitted to NCBI GenBank. In silico analysis revealed considerable diversity and distribution of these resistance genes among different strains of bacteria. Gene structure predictions using GENSCAN showed that blaOXA genes typically contain single exons with moderate GC content, whereas blaNDM genes feature longer exons with higher GC content. Multiple sequence alignment showed that NDM and OXA β-lactamases were highly similar, with only slight differences in a few amino acids. The study also analyzed the physico-chemical properties, functional domains, and phosphorylation patterns of the β-lactamase proteins. Secondary structure prediction indicated a dominance of beta sheets, contributing to protein stability, while tertiary modeling provided insights into their 3D structure. Overall, these findings provide critical insights into the genetic diversity and potential mechanisms of β-lactamase-mediated resistance, offering valuable information for the development of novel therapeutic strategies and surveillance programs.

Viral diseases pose significant threats to global aquaculture, particularly in shrimp farming, which has suffered substantial economic losses due to pathogens such as Infectious Myonecrosis Virus (IMNV) and Decapod Iridescent Virus 1 (DIV1). This study presents a comprehensive scientometric analysis of the research landscape, knowledge structure, and emerging trends related to these two pivotal critical shrimp viruses. Using bibliometric data extracted from the Scopus database, we evaluated publication trends, key contributing countries, institutions, authors, co-authorship networks, and keyword co-occurrence patterns. IMNV-related research demonstrated more established collaborative networks, whereas DIV1 studies have surged only recently, reflecting its status as an emerging pathogen and underscoring the urgent need for intensified research efforts. Thematic clusters reveal molecular characterization, host-pathogen interactions, and viral diagnostics as central areas of focus. This analysis identifies research hotspots, collaborative gaps, and leading contributors, offering guidance for future shrimp disease research. However, challenges persist, including limited cross-border collaboration and the underrepresentation of certain regions. Our findings offer valuable insights for researchers, funding agencies, and policymakers, highlighting the opportunities for interdisciplinary and international collaboration to mitigate the impact of these viral threats in aquaculture systems.

In intensive aquaculture, the outbreaks of infectious diseases are increasing, which demand improved disease management. This study assessed the effects of dietary enrofloxacin (ENF) on Oreochromis niloticus at the recommended (10 mg) and overdose (30 mg/kg biomass/day) for 5 days using integrated biomarker response (IBR). The ENF-fed fish were observed for mortality, residue deposition, oxidative stress, plasma biochemistry, and histopathological anomalies. The withdrawal period and elimination half-life of ENF were estimated. The dosing groups experienced 0.67-2.67% mortalities. An increase in glucose, transaminases, alkaline phosphatase, and creatinine, alongside a decrease in calcium and chloride, indicated altered physiology. The liver and kidney tissues exhibited signs of oxidative stress, as indicated by alterations in malondialdehyde, ferric reducing antioxidant power, total nitric oxide, glutathione S-transferase and catalase levels. Maximum residual accumulation of ENF and its metabolite ciprofloxacin (CIP) was in the liver, followed by muscle+skin, kidney, and plasma. Residues of ENF+CIP persisted in the muscle+skin and kidney at day 42 post-dosing. The projected withdrawal period at a 95% confidence limit was 22 days for the recommended dose group. The elimination half-life followed the kidney> muscle+skin> liver> plasma trend. The IBR scores of the liver were comparatively higher than those of the kidney, indicating that the liver tissues are more prone to oxidative damage. The liver and kidney histopathology revealed dose-dependent damage, which partially recovered after ENF withdrawal. While the recommended dose induced reversible effects, the findings emphasised the need for stringent regulation and adherence to withdrawal to mitigate potential risks to fish and consumers.

Abstract Whiteflies, as polyphagous pests, hold global significance due to their substantial economic impact. In recent times, the exotic bondar’s nesting whitefly (BNW), Paraleyrodes bondari Peracchi (Hemiptera: Aleyrodidae) Martin, has profoundly disrupted the horticultural ecosystem in India. This disruption has garnered significant attention of agricultural communities. The severity of its influence has been exacerbated by shifting of weather patterns and climatic conditions. To address these challenges, a comprehensive study was initiated in a coconut plantation. The primary objectives of this study were to unravel the factors that exert influence on the behavior of the bondar’s nesting whitefly and furthermore, to develop predictive models aimed at forecasting its incidence. The correlation studies conducted between biotic and abiotic factors and the population of BNW revealed noteworthy findings. Notably, maximum temperature (with a correlation coefficient i.e. r = 0.28*), bright sunshine hours (r = 0.3*), and canopy temperature (r = 0.28*) exhibited a significant positive influence on the whitefly population build up. These results underscore the crucial role that climatic conditions play in driving the dynamics of BNW population. The prediction of BNW outbreaks based on prevailing weather conditions and the timely implementation of appropriate control measures for effective pest management are of paramount importance. Among the prediction models assessed, artificial neural network (ANN) models emerged as the most promising. The model demonstrated superior performance and were identified as the optimal choice for accurately predicting BNW incidence.