Reactive molecules, including oxygen and nitrogen species, serve dual roles in human physiology. While they function as essential signaling molecules under normal physiological conditions, they contribute to cellular dysfunction and damage when produced in excess by normal metabolism or in response to stressors. Oxidative/nitrosative stress is a pathological state, resulting from the overproduction of reactive species exceeding the antioxidant capacity of the body, which is implicated in several chronic human diseases. Antioxidant therapies aimed at restoring redox balance and preventing oxidative/nitrosative stress have demonstrated efficacy in preclinical models. However, their clinical applications have met with inconsistent success owing to efficacy, safety, and bioavailability concerns. This summative review analyzes the role of reactive species in human pathophysiology, the mechanisms of action of antioxidant protection, and the challenges that hinder their translation into effective clinical therapies in order to evaluate potential emerging strategies such as targeted delivery systems, precision medicine, and synergistic therapeutic approaches, among others, to overcome current limitations. By integrating recent advances, this review highlights the value of targeting reactive species in the prevention and management of chronic diseases.

The efficiency of oil contaminated pulp and paper mill sludge (PPMS) stabilization by Eisenia fetida strongly depends on optimal temperature conditions for nutrient recovery and organic pollutant reduction. In Western Newfoundland, Canada, fluctuations in environmental temperature (< 0 °C to 20 °C), limit the year-round viability of vermicomposting. Therefore, PPMS (TS) and PPMS amended cow manure (TSC) were vermicomposted over a 70-day period at three controlled temperatures (12 °C, 17 °C, and 22 °C) to assess the effects of thermal conditions on PPMS stabilization, and vermiremediation efficiency, and population dynamics of E. fetida. While pH remained stable at 17 °C and 22 °C, it decreased significantly at 12 °C (p < 0.000), whereas electrical conductivity increased significantly across all treatments (p < 0.000). The biodegradability coefficient was significantly higher (p < 0.008) in TS at 17 °C and 22 °C while maximum carbon (C) loss and nitrogen (N) enrichment occurred in TSC at 22 °C, resulting in a reduced C:N (<20) by day 56. Oil degradation was faster in TSC compared to TS at 17 °C and 22 °C. A significant increase in macronutrients (P, Na, K, Ca, Mg) and micronutrients (B, Mn, Fe, Al) were observed at 17 °C and 22 °C with the highest enrichment in TSC, followed by TS (p < 0.001). A slight increase in potentially toxic elements (As, Co) was detected in TSC, whereas Zn and V were more prominent in TS at 12 °C. TS exhibited higher levels of Cd, Cu, Ni, and Cr, while Pb and Mo were elevated in TSC at 22 °C. However, all remained below Canadian Council of Ministers of the Environment (CCME) guideline limits. Growth and reproduction of E. fetida and vermicompost production were significantly enhanced (p < 0.0001) at 17 °C and 22 °C, peaking on day 42 while lower at 12 °C. Overall, temperature between 17 °C and 22 °C optimized PPMS vermicomposting and are feasible from late spring to mid fall in Corner Brook, Newfoundland and Labrador, Canada.

The pulp and paper mill industry in Corner Brook, Newfoundland and Labrador, Canada produces 150 Mg/day of pulp and paper mill sludge (PPMS) with a high moisture content (70–80%). Instead of the current practice of burning, PPMS may be repurposed as vermicompost. However, the optimum population density of Eisenia fetida to maximize the bioconversion process and its influence on population dynamics are largely unknown. The current study aimed at determining how stocking densities affect the vermicomposting time, vermicompost quality, and population dynamics of E. fetida. By using three stocking densities—1.13 g (TL), 2.04 g (TM), and 3.01 g (TH)—the E. fetida per kg of PPMS and the quality of the vermicompost were determined by chemical analysis followed by a germination test and bioassay on Raphanus sativus seedlings. The total vermicompost produced in TL (66.3%) and TM (68.8%) made the bioconversion process quicker in 60 days. The addition of more E. fetida (TH) delayed the process of vermicomposting by up to 90 days (p < 0.003). Overall, 0.87 (TM) E. fetida/L of PPMS was found to be the optimum population density for obtaining the best quantity and quality of vermicompost. The highest earthworm biomass was harvested in TL, followed by TM and TH, as 3.2, 1.3, and 0.9-fold, respectively, compared to the introduced biomass in 60 days (p < 0.008). The mean growth rate (2.6 mg/worm/day), biomass gain (3.49 mg/g), and reproduction rate (3.9 cocoon/worm) were also significantly higher (p < 0.023) in TL compared to TM and TH in 60 days. Therefore, the present study shows the importance of using an optimum stocking density to maximize the bioconversion process in PPMS, especially in cooler regions.

Large quantity (150 Mg/day) of Pulp and Paper Mill Sludge (PPMS) is being generated in Corner Brook Pulp and Paper Limited (CBPPL), Newfoundland, Canada. Since PPMS contains high level of organic matter-OM (80-85%) and moisture content-MC (50-60%), it may be considered for recycling as vermicompost and earthworm as animal feed. An initial attempt on vermicomposting PPMS using Eisenia fetida had a long processing time up to 80-90 days. Therefore, the current study was designed to shorten the processing time by amending PPMS with different organic wastes and monitoring production performance of Eisenia fetida.Organic wastes - poultry bedding material (SP), vegetable peels (SV), soil (SS), fresh cow manure (SC-L) and composted cow manure (SC-C) were amended separately with PPMS in 2:1 ratio as the treatments while PPMS alone was the control (S). About 14.1-14.5 g of earthworms/ 3.6 kg of substrate (an average stocking density of 4 g/kg) were introduced in all the treatments which were triplicated in completely randomized design. Changes in vermicompost parameters such as pH, electrical conductivity (EC), OM, MC, etc. were monitored weekly and the population dynamics of earthworms were studied, bi-weekly. The MC was maintained at about 75-80% in all the treatments. Results showed that amending organic wastes with PPMS had a significant (p< 0.0001) influence on the quality and quantity of the final vermicompost produced. The total quantity of vermicompost produced was higher (73.8%) in SC-L followed by SV (70.4%), SC-C (69.8%), SS (67.3%), S (64.3%) and SP (8.8%) in 45 -50 days. pH decreased in all the treatments except in control until 30 days and increased afterward to reach the range between 6.1 and 7.3. EC in all the treatments S, SV, SS and SC-L (except SP and SC-C) reduced from the initial value of 2.90, 2.66, 1.23 and 3.18 to 2.58, 2.56, 2.69 and 2.69 mS/cm, respectively. Simultaneously, OM content showed a decline in all the treatments, while the reduction rate was higher in SS (4.71%) > SV (4.02%) > SP (3.94%) > SC-L (2.91%) > SC-C (2.67%) > S (1.81%). Total biomass gain of Eisenia fetida was 56.1%, 40.4%, 22.3% and 13.4% in SC-L, SC-C, SV and SS, respectively in day 45. Conversely, a reduction in earthworm biomass of 55.8% and 60.1% was observed for S and SP, respectively. The average biomass growth rate was higher in SC-L (1.73 g/day) followed by SV (1.35 g/day) and SS (1.22 g/day). As a whole SC-L, SC-C, SV and SS had no significant difference (p> 0.05) among them in both total biomass gain and growth rate while those treatments had the significant difference with S and SP (P< 0.0001). Therefore, we conclude that the PPMS can be an excellent substrate to reuse in vermicomposting. However, incorporating various organic manures and wastes could enhance the vermicomposting rate and significantly reduce the processing time. Further improvements can be achieved by adjusting factors such as the types and ratio of organic wastes, and the number of earthworms involved.Keywords: Eisenia fetida, PPMS, cow manure, vegetable peels, poultry bedding, soil

The growing reliance on fishmeal in aquaculture is increasingly unsustainable due to rising costs, ecological concerns and market competition, emphasizing the need for alternative protein sources. Eisenia fetida, a non-conventional protein-rich earthworm, offers promising nutritional values including high levels of protein, lipids, sugars, and vitamins while thriving on various organic substrates. The Corner Brook Pulp and Paper Mill generates substantial quantities of carbon-rich pulp and paper mill sludge (PPMS), which is typically incinerated without considering alternate uses. To address this problem, this study investigated the use of PPMS as a substrate for cultivating E. fetida and systematically compared the biochemical profile changes of earthworms to provide insights into their potential use/utilization as a sustainable alternative protein source for poultry and aquaculture feeds. E. fetida were cultured in varying PPMS-to-cow manure ratios (100%, 75%, 67%, 60%, 50%, and 0%) to modulate carbon content and optimize growth, and were analyzed for total phenolic content (TPC), total antioxidant activity (TAA), total soluble protein, lipids, soluble sugar, vitamins, and mineral content. Statistically-significant differences (p < 0.05) were observed across all treatments. The highest total soluble protein content was found in the cow manure (TS-0), with soluble protein content decreasing as the PPMS proportion increased. Conversely, E. fetida cultured in PPMS (TS-100) exhibited higher levels of TPC, TAA, total lipids, sugar, and water-soluble vitamins B₁, B₂, B₃, B₅, B₆, K₂ and K₃, surpassing those reported in other alternative fishmeal sources. Total essential macro, micro, and non-essential heavy metals were significantly higher (p < 0.05) in TS-0 except for arsenic (TS-100). Based on their biochemical composition, E. fetida cultured on 50–67% of PPMS exhibit a nutrient profile indicative of their potential use as a protein source for aquaculture and poultry, with this range suggesting a potentially cost-effective substrate proportion for PPMS valorization and reduced accumulation of potentially toxic elements (PTE), while future controlled feeding trials are warranted to confirm their nutritional value and digestibility.