Silver nanoparticles (AgNPs) were produced through an ethanol reduction approach enhanced by ultrasonic agitation to boost dispersion and reaction effectiveness. Tamarind seed polysaccharide (TSP), an eco-friendly and non-toxic polymer, served as the stabilizing agent. Optimal results were obtained using 0.01001 M AgNO3, 800 mg/L TSP at pH 7 or higher, with sonication for 60 min. The nanoparticles produced exhibited a distinctive surface plasmon resonance (SPR) peak within the range of 416-434 nm, validating their synthesis. The deep yellow hue of the colloidal solution suggested the effective reduction of Ag+ to metallic Ag-0. Increased TSP concentrations resulted in enhanced stability of nanoparticles, decreasing aggregation and aligning with earlier research. Antimicrobial assessment demonstrated significant effectiveness against Vibrio natriegens, presenting an average inhibition zone of 1.90 cm, over twice that of the positive control (amoxicillin, 0.90 +/- 0.10 cm, p < 0.05). The estimated minimum inhibitory concentration (MIC) is 1.3 & times; 10(-3) M. This reinforces current evidence regarding the antibacterial properties of AgNPs, probably caused by the disruption of cell membranes and the generation of reactive oxygen species. UV-vis analysis revealed consistent findings, with statistically significant variations in absorbance at the 95% confidence level, emphasizing the method's reliability.
Vibriosis, a bacterial disease, is considered a significant threat to the sustainability and economic viability of shrimp production. The present study evaluated the application of a predatory bacterium to control the population growth of pathogenic Vibrios in Pacific whiteleg shrimp (Penaeus vannamei). The predatory bacterium was identified as Bacteriovorax sp. OP175948.1 based on the 16S rRNA sequence. The Vibrio-inhibitory activity of Bacteriovorax sp. was evaluated using two independent trials with P. vannamei, exposed to two pathogenic Vibrios, including Vibrio parahaemolyticus and Vibrio harveyi. Each trial was conducted in five treatments, including a negative control, a positive control, and a treatment with Bacteriovorax sp. applied at 102, 104, and 106 plaque-forming units mL-1 (PFU mL-1). Results indicated that shrimp infected with V. parahaemolyticus and V. harveyi, and then treated with Bacteriovorax, showed a 6-fold increase in survival for V. parahaemolyticus and a 3-fold increase for V. harveyi, relative to the control. The shrimp treated with 104 to 106 Bacteriovorax sp. improved survival associated with a significant decline in Vibrio spp. counts in the shrimp tissues and rearing water. The Bacteriovorax sp. should be used as a practical strategy to prevent Vibrio-associated mortalities in P. vannamei aquaculture.
Tuna fish solubles (TFS) is a liquid by-product generated from the production of fish meal using tuna processing wastes. In this study, the physico-chemical composition and functional properties of TFS were determined. Proximate analysis showed that it is composed of 41.7 % moisture, 66.0 % protein, 20.1 % ash, and 7.3 % lipid. TFS possessed antioxidant properties as revealed by its radical scavenging activity against 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) at half maximal inhibitory concentrations (IC50) of 4.17 mg·ml-1 and 2.1 mg·ml-1, respectively, and reducing power (6.17–50.40 mmol·kg-1 expressed as ascorbic acid). Its protein solubility in pH 2 to 12 ranged from 38.6 % to 64.4 %. It also exhibited foaming expansion of 5.1 % to 7.7 %, foaming stability of 4.7 % to 7.1 % and an emulsion activity of 1283.09 m2·kg-1 to 1398.58 m2·kg-1. Furthermore, liquid chromatography-mass spectrometry (LC-MS) analysis detected ions whose accurate masses match metabolite classes including alkaloids, glycosides, peptides, and terpenoids, though these require confirmation by further analysis. The findings indicate the potential of TFS as a source of antioxidant compounds and functional ingredients for industrial applications. Recovering valuable products from tuna wastes can promote a more sustainable aquatic food industry.
Introduction/Objective Fish are a rich source of lipids, particularly omega-3 polyunsaturated fatty acids (PUFAs), which are known to reduce cardiovascular disease risk and support human health. Processing of fish generates significant by-products, including heads, viscera, and tails, which contain recoverable lipids. Conventional extraction methods often involve high temperatures and toxic solvents, compromising lipid bioactivity and safety. This study aimed to optimize enzymatic hydrolysis using Alcalase (R) for lipid recovery from sardine (Sardinella spp.) processing wastes and to evaluate the quality and biological activities of the refined oil.Methods Oil extraction was optimized using a central composite design of response surface methodology (RSM) with three independent variables: hydrolysis time, enzyme concentration, and temperature. Recovered oil was refined through degumming, neutralization, bleaching, and deodorization. The refined oil was analyzed for physicochemical quality parameters, fatty acid profile, and bioactivities, including antioxidant and anti-inflammatory effects.Results Optimal hydrolysis conditions were 3 h, 0.80% enzyme concentration, and 57.5 degrees C, yielding 8.74% +/- 0.12 crude oil. Refining improved key quality indices, including peroxide value, thiobarbituric acid reactive substances, free fatty acids, fatty acid composition, and color, while retaining PUFA content. EPA and DHA concentrations increased to approximately 52-59%. Refined oil exhibited notable bioactivities such as DPPH scavenging activity (23.47-55.97%), cyclooxygenase-2 inhibition (26.38-81.94%), 5-lipoxygenase inhibition (22.51-70.41%), and protein denaturation inhibition (34.9-89.6%).Discussions Results of the study revealed that using RSM in optimizing enzymatic conditions resulted in maximum oil recovery. Oil yield was affected by the interactive effects of the hydrolysis time and temperature, and enzyme concentration. Increasing the extraction time and enzyme concentration enhanced oil yield up to the optimum point. Refining the extracted oil removed impurities and oxidation products without reducing PUFA levels, thereby increasing biological activities.Conclusions Enzymatic hydrolysis and subsequent refining of sardine processing waste efficiently recover bioactive lipids with retained PUFA content. The refined oil demonstrates significant antioxidant and anti-inflammatory activities, highlighting its potential as a natural alternative to synthetic drugs and as a sustainable source of functional ingredients for nutraceutical and functional food applications.
Milkfish is considered to be one of the prominent products associated with the aquaculture business within the Philippines, as well as a significant source of food security within the country. The national production data are readily available; however, region-specific information, particularly within the Davao Region, requires comprehensive analysis and system-level characterization to inform production, governance, and sustainability pathways. This review frames Davao’s milkfish aquaculture as a regional bioeconomic system, defined here as the interaction of biological productivity, economic behavior of producers and markets, and governance and sustainability mechanisms that collectively shape production outcomes. The Davao Region is recognized as one of Mindanao’s strongest milkfish-producing areas, supported by favorable biophysical features, extensive coastal resources, and expanding semi-intensive pond and cage-culture operations. Drawing from peer-reviewed literature, national datasets, and regional fisheries reports, this review synthesizes the socio-biological foundations of the industry, the advancement of culture systems, production and trade trends, and the governance structures that influence development trajectories in the region, highlighting the role of public–private partnerships, national agency programs, and research and development interventions in addressing fry sufficiency and enhancing production capacity. In the bioeconomic context, the production developments in the Davao Region are seen as a function of interacting biological constraints, such as fry availability; economic incentives, such as the extent of input application and the prevailing demand in the market; and regulatory environments, such as zoning, seed management, and farm management practices. This reflects the opportunities and persistent challenges, including continued dependence on wild fry, vulnerability to climate-induced impacts such as sea-level rise and extreme weather events, and the mixed provincial growth performance. Within this framework, it gave us an overview of the Davao milkfish regional bioeconomic system and its contribution to regional economies and further underlines that adaptive governance, sustained hatchery investments, and context-specific sustainability frameworks shape long-term development of the Philippine milkfish industry.
