The increase in the usage of silica nanoparticles (SiNPs) in the industrial and medical fields has raised concerns about their possible adverse effects on human health. The present study aimed to investigate the potential adverse effects of SiNPs at daily doses of 25 and 100 mg/kg body weight intraperitoneally (i.p.) for 28 consecutive days on markers of liver damage in adult male rats. Results revealed that SiNPs induced a marked increase in serum markers of liver damage, including lactate dehydrogenase (LDH), alanine aminotransferase (ALAT), and aspartate aminotransferase (ASAT). SiNPs also induced an elevation of reactive oxygen species (ROS) production in liver, along with an increase in oxidative stress markers (NO, MDA, PCO, and H₂O₂), and a decrease in antioxidant enzyme activities (CAT, SOD, and GPx). Quantitative real-time PCR showed that SiNPs also induced upregulation of pro-apoptotic gene expression (including Bax, p53, Caspase-9/3) and downregulation of anti-apoptotic factors Bcl-2. Moreover, histopathological analysis revealed that SiNPs induced hepatocyte alterations, which was accompanied by sinusoidal dilatation, Kupffer cell hyperplasia, and the presence of inflammatory cells in the liver. Taken together, these data showed that SiNPs trigger hepatic damage through ROS-activated caspase signaling pathway, which plays a fundamental role in SiNP-induced apoptosis in the liver.

Cyprinid fishes have one of the simplest types of gastrointestinal tract among vertebrates. Those fish species do not possess a true stomach that is replaced by a simple dilatation at the anterior part of the intestine called the intestinal bulb. Twenty adult specimens of grass carp were used in the present study to identify the cellular components as well as the immunohistochemical and surface architectural characteristics of the intestinal bulb. The mucosa of the intestinal bulb shows numerous, deep longitudinal folds arranged in zigzagging-like patterns.
The epithelium is composed mainly of absorptive columnar cells covered by microvilli and mucous goblet cells. Spindle-shaped enteroendocrine cells and some migratory immune cells such as intraepithelial lymphocytes and rodlet cells could be identified between the absorptive cells. The epithelium also contains many secretory granules and large numbers of vacuoles containing digestive enzymes  mostly in the basal part. The immunohistochemistry revealed that CD20-positive B-lymphocytes are immunolocalized mainly in the
connective tissue core lamina propria of the mucosal folds. However, CD3-immunopositive T-lymphocytes are highly concentrated in the lamina propria. In addition, intraepithelial T-lymphocytes expressed immunopositivity to CD3. The current study presented many types of immune cells and suggests their essential immunological role for the intestinal blub.

Overproduction of free radicals is controlled by antioxidant defense mechanisms. These defense mechanisms are achieved by antioxidant enzymes such as catalase (CAT). The current study aimed to assess the changes in steroid hormones, oxidant/antioxidants biomarkers, lipid profiles/liver functions indices, renal function biomarkers and minerals metabolism in non-pregnant, lactating or pregnant one-humped she-camels (Camelus dromedarius) pre-synchronized with controlled internal drug releasing. The study also focused on the correlational relationships between steroid hormones and the oxidant/antioxidant biomarkers, lipid profiles and liver functions indices, renal functions and mineral metabolism in these she-camels. The study was conducted on apparently healthy dromedary she-camels (n = 60) during breeding season. A sexually active camel-bull was introduced to she-camels pre-synchronized with CIDR. Fifty to sixty days after natural mating, she-camels were examined for pregnancy. She-camels were divided into three main groups according to both pregnancy and lactation as following: pregnant (PREG, n = 38) which was kept as control one, non-pregnant and lactating (LACT, n = 8), and non-pregnant and non-lactating she-camels (NPREG, n= 14). Steroid hormones, i.e., progesterone (P₄), estradiol (E₂) and cortisol, oxidant indictors, i.e., malondialdehyde (MDA), antioxidant biomarkers, i.e., superoxide dismutase (SOD), total antioxidant capacity (TAC), CAT and reduced glutathione (GSH), lipid profiles indices, renal functions and related minerals were assessed. The present study confirmed the efficacy of using CIDR for synchronization in she-camels. Significant elevations in serum steroids hormones in PREG compare with LACT and NPREG. The highest concentrations of MDA as lipid peroxidation and oxidative stress indictors and lowest levels of antioxidant biomarkers except for SOD, i.e., TAC, CAT and GSH, were reported in PREG compared with LACT and NPREG. PREG showed the highest liver enzymes activities and lowest total protein values. Remarkable increases in serum concentrations of renal function parameters and phosphorous (P) were observed in PREG when compared with the other two groups. The investigated she-camels revealed significant correlation between steroid hormones and the oxidant biomarkers, antioxidant biomarkers, liver functions, renal functions and minerals metabolism parameters. P₄ showed positive correlations with antioxidant biomarkers, i.e., TAC, CAT and GSH, and serum aspartate aminotransferase (AST) activities, whereas negative correlations were reported between P₄ and renal functions biomarkers, i.e., blood urea nitrogen (BUN), creatinine (Cr) and creatinine kinase (CK), and minerals metabolism parameters, i.e., P and magnesium (Mg), in CIDR pre-synchronized she-camels. In contrast, E₂ and cortisol showed negative correlations with antioxidant biomarkers, i.e., TAC, CAT and GSH, lipid profiles/liver functions indices, i.e., AST, alkaline phosphatase (ALP) and γ-glutamyl transferase (GGT), CK and Mg, however, positive correlations were demonstrated between E₂ and cortisol, and MDA, Cr and P in investigated she-camels. In conclusion, the present study confirmed the efficacy of using CIDR for synchronization in she-camels. The highest MDA levels as indictors for oxidative stress and the lowest antioxidant levels, i.e., TAC, CAT and GSH, except for SOD in pregnant she-camels, were attributable to physiological oxidative stress as excellent compensatory responses observed in the PREG group to face such a physiologic stage. Moreover, lower P levels in non-pregnant she-camels would be contributed to failure of conception or early embryonic death. The investigated she-camels revealed significant correlations between steroid hormones and the oxidant indicators, antioxidant biomarkers, lipid profile indices and renal functions biomarkers that provided better understanding for physiological stress during pregnancy in camels.

Cryptosporidium is a protozoan of extremely medical and veterinary impact; whose oocysts donate a considerable resistant to the water treatment processes. Therefore, this study aimed to explore the impacts of silver nanoparticles (AgNPs) on count and viability of the Cryptosporidium parvum (CP) isolated from different tap water samples. The oocysts were exposed to AgNPs at different dosages of 0.05, 0.1 and 1 ppm for several contact times (30 min to 4 h). The results showed a significant decrease in oocyst count and viability in a dose-dependent manner. Additionally, AgNPs at a conc. of 1 ppm for 30 min and 0.1 ppm for 1 h reduced the oocysts by 97.2 and 94.4%, respectively. Comparatively, there was a noticeable increase in the oocyst's viability at 2 and 4 h, which emphasized that the time of contact between AgNPs and CP was not a major influencing factor for successful application of AgNPs in the nano-water treatment.

Utilization of macroalgal biomass through the anaerobic digestion (AD) system can overcome algal pollution while providing alternative and renewable energy as fuel scarcity increases. To achieve this objective, Sargassum fulvellum biomass was used as the feedstock for the batch AD process. Original-sized algal biomass (So) of 106 µm–4.75 mm particle size, reduced-sized biomass of 75–850 µm (mechanically pretreated, Sr), chemically pretreated reduced-sized wet biomass with 40 mL/L (Sac1), 20 mL/L (Sac2) of 2 M HCl and with 10 mL/L (Sal1) and 5 mL/L (Sal2) of 6 N NaOH, and biologically pretreated original particle size biomass (Se) with 1 mL/L of cellulase enzyme were employed as feedstocks for digestion. Mechanical pretreatment of Sargassum fulvellum (Sr) without chemical addition resulted in 142.91 ± 0.004 mL CH₄/gVS, which is higher than chemically pretreated reduced-sized macroalgae in So, Sac1, Sac2, Sal1, and Sal2 by 52.34%, 9.83%, 15.89%, 12.73%, and 18.26%, respectively. Biological treatment reduced methane yield in Se by 9.49% than the original-sized algal biomass (So). In addition, the rate of hydrolysis and maximum biomethane production potential improved after mechanical pretreatment by a maximum of 45.60% and 48.71%, respectively. This study indicates that the utilization of marine biomass as an alternative resource for biomethane production can be achieved, with an optimum methane production from mechanically pretreated macroalgae without chemical addition.

The employment of macroalgal biomass in anaerobic digestion (AD) systems could provide an alternative and renewable energy source and overcome the concern of algal influx. Sargassum fulvellum macroalgae was applied in the batch digesters as raw algal biomass (M_raw), enzymatically treated biomass (M_enz), reduced-sized biomass (M_red), chemically pretreated reduced-sized biomass with 0.36 mL g⁻¹ VS (M_acid1) and 0.18 mL g⁻¹ VS (M_acid2) of 2 M HCl and with 0.09 mL g⁻¹ VS (M_alkali1) and 0.04 mL g⁻¹ VS (M_alkali2) of 6 M NaOH. The results of this study indicated that the biologically treated digester (M_enz) enhanced the methane yield to 186.60 mL g⁻¹VS, which corresponds to 116.64% and 33.48% increases over those in the M_red and M_raw, respectively. Additionally, chemical pre-treatments of Sargassum fulvellum enhanced the methane outcome by 15.11%, 6.53%, 45.65%, and 37.01% for M_acid1, M_acid2, M_alkali1, and M_alkali2, respectively, compared with the M_red. This study emphasized that the utilization of raw untreated Sargassum fulvellum macroalgae through the thermophilic AD system was better than chemical and mechanical pre-treated feedstocks, which verified the eco-benefits and sustainable biomass management approach. The gas recovery of raw macroalgae can be further improved through the supplementation with a cellulase enzyme.

Anaerobic digestion (AD) is a sustainable technology that combines biogas production with proper waste management. However, the operation of an anaerobic reactor under the stress of nanoparticles (NPs) is unknown. Therefore, this study assessed the disadvantages and advantages of adding two NPs to 11 L semi-continuous stirred-biodigesters and examined their contributions to biogas generation. Iron oxide NPs (INPs) and titanium oxide NPs (TNPs) were mixed daily with manure from dairy cattle and added to the biodigesters daily at concentrations of 100 mg/L (D1) and 500 mg/L (D2), respectively. In addition, a control with no NP supplementation was studied (D0). The results revealed that the generation rates of biogas and CH₄ increased by 25.43 and 62.43%, respectively, for D1 during the first 7-day retention time, as compared with the D0. Conversely, TNP addition reduced the generation rates by 28.76 and 56.92%, respectively, during the same period. Overall, for D1, the biogas and CH₄ yields over the study period increased by 5.48 and 12.35%, respectively, whereas for D2, the rates were reduced by 11.36 and 18.58%, respectively. Therefore, the presence of INPs had a stimulatory influence while that of the TNPs had an inhibitory effect.

Intensification of the livestock industry has become environmentally problematic due to the uncontrolled treatment of large amounts of watery manure. One solution is the adoption of biogas plants (BGPs). Hokkaido, Japan, has significant potential for BGP adoption, however, the large financial investments and lack of grid space for selling electricity are barriers. We investigated the relationship between the willingness of farmers to adopt BGPs and their current farming situations. Using a questionnaire survey and multivariate analyses, the results showed that large-scale farmers, particularly those with more than 100 mature cows, were clearly willing to adopt BGPs and expand their businesses in the future, while farmers who planned to downsize their businesses did not exhibit strong willingness to adopt BGPs. In addition, farmers willing to adopt BGPs thought the plants would help solve problems with manure treatment. BGPs might be more accepted by dairy farmers if there were greater incentives for installation given the role BGPs can play in providing stable energy and revitalizing local economies.

Improving the quality and quantity of biogas usually requires pre-treatment to maximize methane yields and/or post-treatment to remove H₂S, which involves considerable energy consumption and higher costs. Therefore, this study proposes a cost-effective method for the enhanced anaerobic digestion (AD) of dairy manure (DM) without pre/post-treatment by directly adding waste iron powder (WIP) and iron oxide nanoparticles (INPs) to batch digesters. The results showed that the addition of iron in the form of microscale WIP (generated from the laser cutting of iron and steel) at concentrations of 100 mg/L, 500 mg/L, and 1000 mg/L improved methane yields by 36.99%, 39.36%, and 56.89%, respectively. In comparison, the equivalent dosages of INPs improved yields by 19.74%, 18.14%, and 21.11%, respectively. Additionally, the highest WIP dose (1000 mg/L) achieved the maximum improvement in the rate of hydrolysis (k), which was 1.25 times higher than in control reactions, and a maximum biomethane production rate (R_max) of 0.045 L/gVS/d according to kinetic analysis models (i.e., first-order and the Gompertz kinetic models). The rate of H₂S production was also significantly reduced (by 45.20%, 58.16%, and 77.24%) using the three WIP concentrations in comparison with INPs (which achieved reductions of 33.59%, 46.30%, and 53.52%, respectively). Therefore, the direct mixing of WIP with cattle manure is proposed as a practical and economical means of addressing complex and high-cost pre- and post-treatments that are otherwise required in the digestion process.