Changes In Enzyme Activities Research Articles

Nanomaterial marvels: Pioneering applications and cutting-edge advancements in drug delivery

Nanotechnology has revolutionized the field of medicine, particularly in the development of novel drug delivery systems. Nanomaterial-based drug delivery systems offer several advantages over traditional methods, including enhanced therapeutic efficacy, improved bioavailability, targeted delivery, and reduced side effects. This review provides an overview of the applications and recent advancements in nanomaterial-based drug delivery systems. The first section of this review focuses on the different types of nanomaterials used in drug delivery, including liposomes, polymeric nanoparticles, dendrimers, carbon-based nanomaterials, and metallic nanoparticles. Each nanomaterial has unique physicochemical properties that can be tailored to optimize drug encapsulation, release, and targeting. The second section highlights the importance of nanoscale characterization techniques in evaluating the properties and performance of nanomaterial-based drug delivery systems. Characterization techniques such as dynamic light scattering, transmission electron microscopy, atomic force microscopy, and spectroscopic methods enable researchers to analyze particle size, morphology, surface charge, drug loading, and release kinetics. The third section discusses the application of nanomaterial-based drug delivery systems in various therapeutic areas, including cancer treatment, cardiovascular diseases, infectious diseases, and neurological disorders. These systems can be engineered to selectively accumulate at the target site, enhancing drug efficacy and minimizing off-target effects. The fourth section explores recent advancements in nanomaterial-based drug delivery systems, including stimulus-responsive and multifunctional nanocarriers. Stimuli-responsive systems can release drugs in response to specific triggers, such as changes in pH, temperature, or enzymatic activity, leading to site-specific drug release. Multifunctional nanocarriers combine drug delivery with diagnostic imaging, allowing real-time monitoring of drug distribution and therapeutic response. The final section addresses the challenges and future perspectives in the field of nanomaterial-based drug delivery systems. Challenges include regulatory considerations, toxicity concerns, scalability, and clinical translation. Future directions involve the development of personalized nanomedicine, combination therapy approaches, and integration with other emerging technologies, such as artificial intelligence and gene editing. In conclusion, nanomaterial-based drug delivery systems have shown great potential for improving the efficacy and safety of therapeutic interventions. The advancements in nanotechnology offer exciting opportunities for the development of next-generation drug delivery platforms, opening new avenues for personalized medicine and targeted therapies. However, further research and collaborations are required to address the challenges associated with clinical translation and ensure the safe and effective implementation of these systems in clinical practice.

Turmeric Powder Counteracts Oxidative Stress and Reduces AFB1 Content in the Liver of Broilers Exposed to the EU Maximum Levels of the Mycotoxin.

The most frequent adverse effects of AFB1 in chicken are low performance, the depression of the immune system, and a reduced quality of both eggs and meat, leading to economic losses. Since oxidative stress plays a major role in AFB1 toxicity, natural products are increasingly being used as an alternative to mineral binders to tackle AFB1 toxicosis in farm animals. In this study, an in vivo trial was performed by exposing broilers for 10 days to AFB1 at dietary concentrations approaching the maximum limits set by the EU (0.02 mg/kg feed) in the presence or absence of turmeric powder (TP) (included in the feed at 400 mg/kg). The aims were to evaluate (i) the effects of AFB1 on lipid peroxidation, antioxidant parameters, histology, and the expression of drug transporters and biotransformation enzymes in the liver; (ii) the hepatic accumulation of AFB1 and its main metabolites (assessed using an in-house-validated HPLC-FLD method); (iii) the possible modulation of the above parameters elicited by TP. Broilers exposed to AFB1 alone displayed a significant increase in lipid peroxidation in the liver, which was completely reverted by the concomitant administration of TP. Although no changes in glutathione levels and antioxidant enzyme activities were detected in any treatment group, AFB1 significantly upregulated and downregulated the mRNA expression of CYP2A6 and Nrf2, respectively. TP counteracted such negative effects and increased the hepatic gene expression of selected antioxidant enzymes (i.e., CAT and SOD2) and drug transporters (i.e., ABCG2), which were further enhanced in combination with AFB1. Moreover, both AFB1 and TP increased the mRNA levels of ABCC2 and ABCG2 in the duodenum. The latter changes might be implicated in the decrease in hepatic AFB1 to undetectable levels (<LOD) in the TP supplemented group. Overall, our findings further support the use of TP as an effective feeding strategy to prevent AFB1-related adverse effects in broilers.

Selective fast fiber damage after leg press exercise leading to failure: a pole vaulter case report

The aim of this study was to investigate, in a trained pole vaulter (PV) and in an endurance-trained physical education student (PE), the effect of a leg press exercise leading to failure (LPF) on changes in serum activity of muscle enzymes and serum concentration of fast (FM) and slow (SM) myosin isoforms, while simultaneously examining mechanical output components as indicators of performance and fatigue developed throughout exercise. A case report study design based on an observational comparison of response between two dichotomous participants, PV and PE, was used. Differences between the participants’ exercise outputs were examined by unpaired t-test or Mann-Whitney test and serum levels of muscle enzymes and myosin isoforms were analyzed at baseline and 24 and 48 hours after LPF. Exercise output analyses showed that the PV’s average fatigue index was significantly higher (P = 0.004). Moreover, during the first six sets, the concentric average power exerted by the PV was significantly (P &lt; 0.01) higher (range: 14% to 35%) than that of the PE. The PV only showed acute mild increases of serum creatine kinase (CK) and FM 24 hours after exercise. In contrast, the PE presented persistent serum rises of several muscle enzymes and SM until 48 h after exercise. The PV’s exercise output revealed an explosive (power-oriented) profile leading to selective mild damage of fast fibers. In contrast, the PE exercise output showed a fatigue-resistant profile, which induced greater muscle enzyme activity and SM serum concentration, suggesting a higher extent of slow fiber damage. Keywords: muscle damage, creatine kinase, myosin isoforms, power output.

Activities of Energy Metabolism Enzymes in Atlantic Salmon Salmo salar L. Smolts and Parr Grown under Different Light Regimens.

Activities of enzymes of energy and carbohydrate metabolism in muscles and the liver were studied in Atlantic salmon Salmo salar L. smolts and parr grown under continuous or natural lighting and different feeding regimens in autumn followed by a short photoperiod in winter. Enzyme activities were found to differ between test and control salmon groups and between parr and smolts sampled at the end of the winter period. Smolts grown under continuous lighting and round-the-clock feeding differed from other groups by having higher cytochrome c oxidase (COX) activity and lower aldolase activity in muscles. Differences in aerobic metabolism in muscles between parr and smolts were found to be the same in all experimental groups, COX and aldolase activities being relatively higher in smolts. The pattern of changes in enzyme activities in the liver from parr to smolts differed between different experimental groups. Based on the results, the photoperiod was assumed to affect the activities of energy metabolism enzymes in salmon juveniles and may eventually affect the completion of smoltification.

Effect of ultrasonic treatment on enzymes: Decoupling the relation between the ultrasonic driven conformational change and enzyme activity

Considering the growing interest in enzyme-based extraction technology as a safe and eco-friendly extraction technique, along with the relatively high cost associated with enzymatic applications, it became necessary to explore novel strategies aimed to improve enzyme activity. In this study, the impact of ultrasonic treatment on commercial cellulase and pectinase was investigated. As this effect may be influenced by various ultrasonic and enzyme-related parameters, changes in enzyme conformation were explored under optimal and non-optimal enzyme conditions. The intrinsic fluorescence spectrum was utilized as a tool for monitoring these changes. Additionally, the enzyme’s catalytic potential was also assessed under the same conditions. Results indicated that the impact of ultrasonic treatment on enzyme conformation primarily depends on the total ultrasonic energy delivered to the system, rather than other ultrasonic parameters such as power, sample volume, treatment time, or duty cycle. The maximum relative decrease in intrinsic fluorescence intensity of Pectinex® Ultra Clear (PUC) and Pectinex® Ultra SPL (PUS) after ultrasonic treatment was approximately 51% and 55%, respectively, while the decrease induced by thermal denaturation was 25% and 30% respectively. Furthermore, a blue shift in the fluorescence spectrum of both pectinases was observed upon sonication for all process conditions indicating a change in enzyme conformation. However, ultrasonic treatment did not result in a significant change in enzyme activity, suggesting that these conformational adjustments may occur in regions other than the active sites. Moreover, ultrasonicated pectinases and cellulases did not exhibit any improvement in their catalytic potential under either optimal or non-optimal conditions.

Changes in Flora Species Composition and Soil Enzyme Activity in Communities of Acer negundo in Kemerovo Region

Changes in Flora Species Composition and Soil Enzyme Activity in Communities of Acer negundo in Kemerovo Region

Changes in antioxidant enzyme activity and lipid peroxidation in Brassica juncea (L.) Czern., by the effect of Indian classical music on the young plant stage

Changes in antioxidant enzyme activity and lipid peroxidation in Brassica juncea (L.) Czern., by the effect of Indian classical music on the young plant stage

Microspheres: A Novel Approach for Sustained Colon Targeted Drug Delivery

Abstract: Colon targeted medication delivery is a field of study for disorders including colon can-cer and inflammatory bowel disease (IBD), with the goal of delivering localised therapy with mini-mal systemic damage. In recent decades, the global prevalence of colonic problems has increased, demanding more local treatment of colonic disorders, which will lead to the development of more effective and safe pharmaceutical regimens. When developing a formulation for colonic administra-tion, it's critical to consider both the physiological characteristics of the colon and the environment surrounding the disease site (s). The GI tract experiences dynamic changes in motility, fluid vol-ume, enzyme activity, and pH from the stomach to the intestine. The current review focuses on Bio-degradable polymers or protein‑based microspheres having free‑flowing properties and particle size 5200 nm have a variety of advantages over conventional colon targeted drug delivery systems. Dur-ing drug transit through the GIT, polysaccharides maintain their integrity and inhibit drug release. When it comes into contact with colonic fluid, however, it is attacked by anaerobic microbes, and the imprisoned medication is released. In this review, several methods of microsphere formulation and characterization were investigated along with its in vitro and in vivo study methodology.

Heat-stress-induced changes in enzymatic antioxidant activities and biochemicalprocesses in bell pepper (Capsicum annuum L.) seedlings

Heat-stress-induced changes in enzymatic antioxidant activities and biochemicalprocesses in bell pepper (Capsicum annuum L.) seedlings

Urea addition as an enhanced strategy for degradation of petroleum contaminants during co-composting of straw and pig manure: Evidences from microbial community and enzyme activity evaluation

Alterations in microbial community succession patterns and enzyme activities by petroleum pollutants during co-composting of straw and swine manure with the supplementary nitrogen source are unclear. In this study, urea was added into co-composting systems, and the removal performance of petroleum, microbial enzyme activity and community changes were investigated. Results showed that the polyphenol oxidase and catalase activities which were both related to the degradation of petroleum contaminants were accordingly increased from 20.65 to 30.31 U/g and from 171.87 to 231.86 U/g due to urea addition. The removal efficiency of petroleum contaminants in composting with urea increased from 45.06% to 82.29%. The addition of urea increased the diversity and abundance of petroleum-degrading microorganisms, and enhanced microbial linkages. This study provides a novel strategy for the degradation of petroleum hydrocarbon as well as a new insight into the effect of urea on both microbial processes and composting phases.

Evaluation of Total and Lipid-Bound Sialic Acids, Trace and Macro Elements, and Some Biochemical Parameters in Dogs with Babesiosis

The present study was designed to investigate the changes at the levels of total sialic acid (TSA), lipid-bound sialic acid (LSA), trace and macroelements, and some biochemical parameters in dogs naturally infected with babesiosis. While babesiosis group consisted of seven dogs which were diagnosed with babesiosis clinically and parasitologically (ELISA), control group consisted of seven healthy dogs. Serum TSA and LSA levels in blood samples were measured spectrophotometrically by Sydow and Katapodis methods, respectively. Some biochemical parameters and macroelement measurements were performed using a modular autoanalyzer device. Trace mineral measurements were performed by ICP-MS technique. Compared to the healthy group, dogs with babesiosis had considerably higher TSA and LSA levels. Serum AST, ALP, LDH and CK enzyme activities and CRP, glucose, globulin, total bilirubin, urea, uric acid, creatinine and BUN levels of the babesiosis group significantly increased, while total protein level significantly decreased. The changes in ALT enzyme activity and triglyceride, cholesterol, HDL, LDL, HDL-CDL and ferritin levels were not statistically significant. Zinc, copper, magnesium, sodium, and potassium levels of the babesiosis group decreased significantly, while iron and chlorine levels increased significantly (p

Mitochondrial Dysfunction in Skeletal Muscle of Rotenone-Induced Rat Model of Parkinson’s Disease: SC-Nanophytosomes as Therapeutic Approach

The development of new therapeutic options for Parkinson’s disease (PD) requires formulations able to mitigate both brain degeneration and motor dysfunctions. SC-Nanophytosomes, an oral mitochondria-targeted formulation developed with Codium tomentosum membrane polar lipids and elderberry anthocyanin-enriched extract, promote significant brain benefits on a rotenone-induced rat model of PD. In the present work, the effects of SC-Nanophytosome treatment on the skeletal muscle tissues are disclosed. It is unveiled that the rotenone-induced PD rat model exhibits motor disabilities and skeletal muscle tissues with deficient activity of mitochondrial complexes I and II along with small changes in antioxidant enzyme activity and skeletal muscle lipidome. SC-Nanophytosome treatment mitigates the impairment of complexes I and II activity, improving the mitochondrial respiratory chain performance at levels that surpass the control. Therefore, SC-Nanophytosome competence to overcome the PD-related motor disabilities should be also associated with its positive outcomes on skeletal muscle mitochondria. Providing a cellular environment with more reduced redox potential, SC-Nanophytosome treatment improves the skeletal muscle tissue’s ability to deal with oxidative stress stimuli. The PD-related small changes on skeletal muscle lipidome were also counteracted by SC-Nanophytosome treatment. Thus, the present results reinforces the concept of SC-Nanophytosomes as a mitochondria-targeted therapy to address the neurodegeneration challenge.

Toxic effects on ciliates under nano-/micro-plastics coexist with silver nanoparticles

Owing to the degradation of plastics, microplastics (MPs) and nanoplastics (NPs) have remained the focus of global attention. Silver nanoparticles (AgNPs) could adversely affect marine organisms due to their broad application. So far, the combined effects of MPs/NPs (strong adsorbents) with AgNPs on marine organisms are scant. Thus, four sizes polystyrene beads (80 nm, 220 nm, 1.07 µm, and 2.14 µm) combined with AgNPs (30 nm) were assessed using ciliated protozoa Uronema marinum. Results showed that MPs/NPs dramatically decrease the abundance, biovolume, and carbon biomass of U. marinum. And, exposure could cause changes of antioxidant enzyme activity and antioxidant content on U. marinum. The combined toxicity of MPs/NPs with AgNPs to ciliates showed an enhanced effect compared to exposure alone. Additionally, the negative effects under exposure of NPs plus AgNPs were more significant than those of MPs plus AgNPs. Transcriptome sequencing showed that co-exposure could affect the energy metabolism and lipid metabolism of ciliates, even cause DNA and protein damage. Our study provided a novel insight and first-hand basic data for the understanding of combined toxicity of MPs /NPs with AgNPs on the basic trophic level ciliated protozoa in marine ecosystems.

New insights into endocrine reproductive toxicity of Microcystis aeruginosa combined with ammonia exposure in zebrafish

The ecological risk posed by MCs-producing M. aeruginosa and elevated ammonia to fish in actual aquatic environments remains uncertain. To address this knowledge gap, we conducted simulations to investigate the endocrine-reproductive toxicity of prolonged exposure (45 d) to Microcystis aeruginosa (2 × 10^6 cells/mL) and 30 mg/L total ammonia nitrogen (TAN) in zebrafish under environmentally relevant conditions. Our results showed that exposure to M. aeruginosa significantly inhibited the body weight, increased gonadosomatic index (GSI), delayed oocyte development, and disrupted endocrine hormonal balance (reduced gonadotropin-releasing hormone (GnRH), and increased estradiol (E2) and testosterone (T)). Mechanistically, it should be attributed to the over-expression of hypothalamic-pituitary-gonadal-liver (HPGL) axis-related genes (cyp11a and cyp17) induced by M. aeruginosa. On the other hand, TAN exposure caused mild damage to zebrafish ovarian tissue and promoted an increase of T levels by inducing the upregulation of steroid hormone synthesis gene (3βhsd) expression in the ovary. It is worth noting that the dysregulation of E2/T ratio in zebrafish ovaries may be attributed to the inhibition of cyp19a1a by both M. aeruginosa and TAN. These results were further confirmed by changes in steroidogenic enzymes activities in the M. aeruginosa or TAN treated groups. Our findings indicated that exposure to M. aeruginosa and TAN had adverse impacts on the reproductive system of zebrafish. And the combined exposure of M. aeruginosa and TAN had more severe effects on the body weight, GSI, pathological changes, hormone levels and HPGL-axis related gene expression in female zebrafish. These results provide compelling evidence regarding the potential risks for reproductive health associated with M. aeruginosa and TAN in eutrophic water bodies experiencing M. aeruginosa blooms, and contribute to the development of effective strategies for monitoring and managing these toxins in aquatic ecosystems.

Comparative investigation on synergistic changes in enzyme activities during vermicomposting of cereal grain processing industry sludge employing three epigeic earthworm species.

The management of cereal grain processing industry sludge through vermicomposting is an emerging prospect for researchers interested in the green economy. This work is designed to enumerate the enzymatic influence of three epigeic earthworm species - Eisenia fetida, Eudrilus eugeniae, and Perionyx excavatus on the industrial sludge. The vermicomposting experiment was conducted in plastic pots by blending the waste materials with 5% cow dung. The dynamics in activities of cellulase, amylase, invertase, phosphatase, protease, dehydrogenase, and urease were studied on 15days intervals till the harvesting period. The periodical observations confirmed that the enzyme activities (in terms of μg reducing sugar/g/hr) of cellulase (26.45-128.09) amylase (205.43-878.96), invertase (105.32-841.65), phosphatase (85.29-435.54), protease (64.21-359.47), dehydrogenase (111.17-587.72), and urease (94.16-476.71) was low in the first 15days of the vermicomposting experiment followed by a sharp increase in the next 45days accompanied by a steady decline until the harvesting is carried out. Emerging statistical tools such as principal component analysis were employed to study the synergistic deviations of the enzymes during the vermicomposting process. The results confirmed that the enzyme activity efficiently influences the bio-oxidation of industrial waste at an individual level as well as synergistic level thereby allowing the vermicompost to mature much before the appearance of any physical symptoms on the surface of the vermireactors.

An enhanced label-free proteomics approach for deep-diving into equine plasma proteome, including the discovery of protein biomarkers for strenuous exercise.

Plasma proteins have been a valuable source of biomarkers for clinical uses and for monitoring of the illicit use of prohibited substances or practices in equine sports. We have previously reported the first use of label-free proteomics in profiling equine plasma proteome. This study aimed to refine the method by systematically evaluating various plasma fractionation methods and the use of narrower precursor mass ranges in data-independent acquisition (DIA) mass spectrometry (MS). Tandem fractionations of equine plasma with octanoic acid precipitation followed by solid-phase extraction (SPE) with C4 cartridges provided the largest increase in the number of new proteins identified. The use of two narrow precursor mass ranges of m/z 400-600 and 600-800 in DIA not only identified most proteins detectable by using a single mass range of m/z 350-1500 but also identified ~27% more proteins. The improved method was applied to analyse the plasma proteome of 'postrace' samples which, unlike other samples, had been collected from racehorses soon after racing. Multivariate data analysis has identified upregulation of 14 proteins and downregulation of six proteins in postrace plasma compared with the non-postrace plasma samples. Literature review of these proteins has provided evidence of exercise-induced haemolysis and changes in antioxidant enzyme activities, kinin system, insulin signalling and energy metabolism after strenuous exercise. The improved method has enabled a deeper profiling of the equine plasma proteome and identified the proteins associated with normal physiological changes after racing which are potential confounding factors in the development of a biomarker approach for doping control.

Structural, defense enzyme activity and chemical composition changes in the xylem of Aquilaria sinensis during fungus induction

Agarwood is a dark resinous wood, of high quality and in a short period, can be formed after inoculation with the efficient fungus in Aquilaria sinensis. However, the action site and mechanism of the fungus inducing the agarwood formation remain unclear. In this work, the efficient fungal infection was used to induce agarwood formation on A. sinensis, and samples were collected according to inoculation time. Subsequently, the xylem structure, histochemistry, defense enzyme activities, and the accumulation and in-situ distribution of chemical composition were investigated. The transition layer (TL) was the critical layer for the continuous accumulation of agarwood, and began to appear in the injection of fungal inducers for 15 days (15D). The parenchyma cells of the xylem rays and interxylary phloem were the main action site of fungus in the formation and accumulation of agarwood. The sesquiterpenes and 2-(2-phenylethyl) chromones (PECs) were mainly accumulated in the agarwood layer (AL) and decay layer (DL), while their relative contents were highest in the injection of fungal inducers for 30 days and 180 days (30D and 180D), respectively. Among them, PECs appeared earlier than sesquiterpenes, and both were flindersia-type PECs. They were mainly concentrated in the cell corners and intercellular layer of the cell wall. In addition, Redundancy analysis (RDA) and Mantel test revealed that the different layer percentage (DLP), phenylalanine ammonia lyase (PAL), and starch grains (SG) were the drivers of PECs, and catalase (CAT) was the driver of sesquiterpenes. Therefore, this study will provide a theoretical foundation for revealing the mechanism of fungus-induced agarwood formation and inducing high-quality and high-yielding agarwood in the future.

Environmental pollutant sodium omadine: toxic effects in zebra fish (Danio rerio)

In recent years one of the most striking results of over-population and consumption activities in the world is the rapid increase in environmental pollutants. Environmental pollutants, one of the harmful consequences of technological and modern life, threaten the health of people and other living organisms. In this study, we aimed to determine the effects of sodium omadine (NaOM) on superoxide dismutase enzyme (SOD) activity as an antioxidant and on 8-OHdG levels as oxidative DNA damage in zebrafish. Zebrafish, obtained from the aquarium fish producer, were stocked in experimental aquariums to ensure their adaptation period to the experimental conditions 15 days before the experiment. The fish were exposed to 1 ug/L and 5 ug/L concentrations of NaOM for 24, 72, and 96 h. SOD enzyme activity (U/100 mg tissue) and 8-OHdG (pg/100 mg tissue) were measured using commercial kits. The statistically significant differences in tissue SOD levels and data for DNA damage between the groups were determined as time and dose-dependent (p < 0.05). Biocidal products are environmental pollutants that cause changes in antioxidant enzyme activities, especially in non-target organisms. Marine pollution and the degradation of ecosystems directly affect people, and the results of the study offer awareness of health problems, environmental pollution, and marine pollution.

Screening and Regulatory Mechanisms of Inter-Root Soil Nematicidal Bacteria of Pinus massoniana

Pine Wilt Disease (PWD), caused by the pathogenic nematode Bursaphelenchus xylophilus, is a systemic infectious disease commonly referred to as the “cancer” of pine trees. This devastating disease has gained this analogy due to its ability to rapidly spread within pine populations, leading to substantial losses in forest resources. The primary objective of this study is to investigate the bioprotective potential and underlying mechanisms of action exhibited by rhizosphere microorganisms associated with Masson pine (Pinus massoniana) in the context of controlling the pine wilt nematode. In this experiment, using high-throughput sequencing, significant differences were observed in the rhizosphere soil microbial communities among healthy Masson pine, standing dead trees, and diseased Masson pine. Furthermore, it was found that these microbial communities exhibited distinct community structures at different levels. This study successfully isolated and screened three strains of highly effective nematophagous bacteria from the rhizosphere soil. The identified strains were Lysinibacillus capsici, Bacillus Paramycoides, and Delftia tsuruhatensis. After applying the bacterial suspensions and fermentation extracts of these three strains to the roots of two-year-old Masson pine seedlings, followed by inoculation with pine wilt nematodes after a four-day period, distinct defense responses were observed in the Masson pine. Notably, the activities of phenylalanine ammonia-lyase (PAL) and peroxidase (POD) were significantly increased, leading to a substantial reduction in the incidence of pine wilt disease. Based on the changes in defense enzyme activities, it can be concluded that the fermentation extract of the Lysinibacillus capsici strain exhibits effective nematocidal effects and induces resistance. The significant biological control efficacy and induction of host defense activity indicate the potential application value of this strain and its metabolites as a biocontrol agent for pine wilt disease.

Mechanisms of Digestive Enzyme Response to Acute Salinity Stress in Juvenile Yellowfin Tuna (Thunnus albacares).

This study investigates the effect of a sudden change in salinity for 48 h on the digestive enzyme activity of juvenile yellowfin tuna. The treatment included a control salinity of 32‱ in natural seawater and an experimental salinity of 29‱. Acute stress experiments were carried out on 72 juvenile yellowfin tuna (646.52 ± 66.32 g) for 48 h to determine changes in digestive enzyme activity in different intestinal sections over time (0 h, 12 h, 24 h, 48 h). The activities of pepsin, trypsin, α-amylase, lipase, and chymotrypsin in the digestive organs (stomach, foregut, and pyloric ceca) of juvenile yellowfin tuna were measured. Pepsin and pancreatic protease in the experimental group were significantly lower than in the control group (p < 0.05). α-amylase showed a fluctuating trend of decreasing and then increasing, and its activity trend was pyloric ceca > foregut > stomach. The lipase activity of gastric tissues decreased at the beginning and then increased, reaching a minimum at 24 h (2.74 ± 1.99 U·g protein-1). The change of lipase in the pyloric ceca and foregut was increasing and then decreasing. The lipase activity trend was pyloric ceca > foregut > stomach. The chymotrypsin showed a decreasing and increasing trend and then stabilized at 48 h with a pattern of pyloric ceca > foregut > stomach. Similarly, the gut villi morphology was not significantly altered in the acutely salinity-stressed compared to the non-salinity-stressed. This study suggests that salinity may change the digestive function of juvenile yellowfin tuna, thereby affecting fish feeding, growth, and development. On the contrary, yellowfin tuna is highly adapted to 29‱ salinity. However, excessive stress may negatively affect digestive enzyme activity and reduce fish digestibility. This study may provide a scientific basis for a coastal aquaculture water environment for yellowfin tuna farming, which may guide the development and cultivation of aquaculture.