The effect of fish and rapeseed oils on growth performance,egg fatty acid composition and offspring quality of sterlet sturgeon (Acipenser ruthenus)

The aim of this study was to evaluate the long‐term effects (7‐month experiment) of diets consisting of fish oil (Kilka fish) and vegetable oil (rapeseed) on the reproductive performance of sterlet sturgeon (Acipenser ruthenus) broodstock. Forty‐five broodstock (990.3 ± 20.05 g) were randomly allocated to three different diet treatments. Three experimental diets were formulated with graded levels of fish oil (100% FO), vegetable oil (100% VO), and a combination of fish and vegetable oil (50% FO + 50% VO). At the end of the 7‐month feeding trial period, the weight gain and final weight were changed significantly different between the treatments (p < 0.05). Broodstock fed the FO + VO diet had higher growth than those fed the only FO or VO diets (p < 0.05). The highest germinal vesicle migration percentage was observed in FO + VO treatment (p < 0.05). The DHA/EPA, DHA/ARA and EPA/ARA ratios in oocyte exhibited a significant difference in the different treatments (p < 0.05). This study indicates that nutrition of broodstock with diet including FO + VO (p < 0.05) can positively affect the growth performance of larvae compared with only FO or VO diets. Furthermore, the high levels of 18:1n‐9, AL and ALA contents in oocytes from broodstock fed VO and the lowest ALA content in oocytes from broodstock fed FO underlined the important role of broodstock diets in the reproductive process and embryonic and/or larval developments of sterlet.     

Biochar-induced changes in soil properties affected immobilization/mobilization of metals/metalloids in contaminated soils

Purpose

Remediation of metal contaminated soil with biochar is attracting extensive interest in recent years. Understanding the significance of variable biochar properties and soil types helps elucidating the meticulous roles of biochar in immobilizing/mobilizing metals/metalloids in contaminated soils.

Materials and methods

Six biochars were produced from widely available agricultural wastes (i.e., soybean stover, peanut shells and pine needles) at two pyrolysis temperatures of 300 and 700 °C, respectively. The Pb-, Cu-, and Sb-contaminated shooting range soils and Pb-, Zn-, and As-contaminated agricultural soils were amended with the produced biochars. The mobility of metals/metalloids was assessed by the standard batch leaching test, principal component analysis and speciation modeling.

Results and discussion

The changes in soil properties were correlated to feedstock types and pyrolysis temperatures of biochars based on the principal component analysis. Biochars produced at 300 °C were more efficient in decreasing Pb and Cu mobility (>93 %) in alkaline shooting range soil via surface complexation with carboxyl groups and Fe-/Al-minerals of biochars as well as metal-phosphates precipitation. By contrast, biochars produced at 700 °C outperformed their counterparts in decreasing Pb and Zn mobility (100 %) in acidic agricultural soil by metal-hydroxides precipitation due to biochar-induced pH increase. However, Sb and As mobility in both soils was unfavorably increased by biochar amendment, possibly due to the enhanced electrostatic repulsion and competition with phosphate.

Conclusions

It is noteworthy that the application of biochars is not equally effective in immobilizing metals or mobilizing metalloids in different soils. We should apply biochar to multi-metal contaminated soil with great caution and tailor biochar production for achieving desired outcome and avoiding adverse impact on soil ecosystem.

     

Forest Fire Risk Zone Modeling Using Logistic Regression and GIS: An Iranian Case Study

Forest fires are an important environmental concern worldwide, affecting the soil, forests and human lives. During the process of burning, soil nutrients are depleted and the soil is subsequently more vulnerable to erosion. Nowadays it is necessary to identify the factors influencing the occurrence of fire and fire hazard areas, in order to minimize the frequency of fire and avert damage. Logistic regression was used to study the forest fire risk and identify the most influential factors in the occurrence of forest fires. Climatic variables (temperature and annual precipitation), human factors (distance from streams and farmland) and physiography (land slope and elevation) were considered and their correlation with the occurrence of fires investigated. Results of model validation and sensitivity of various areas to fire were examined with the ROC coefficient and Hosmer–Lemeshow test. The estimated coefficients for the independent variables indicated that the probability of occurrence of fire is negatively related to land slope, site elevation and distance from farmlands, but is positively related to amount of annual precipitation.     

Phoma black stem severity and phytoestrogen production in annual Medicago spp. is primarily determined by interaction of cultivar and pathogen isolate

Phoma black stem and leaf spot disease (caused by Phoma medicaginis) not only diminishes forage and seed yield but stimulates production of detrimental phytoestrogens in annual Medicago spp. This study aimed to evaluate relationships between disease development from five isolates of P. medicaginis on 16 cultivars with production of coumestrol and 4′-O-methylcoumestrol. In the presence of P. medicaginis, Sava had the highest coumestrol and 4′-O-methylcoumestrol (640 and 85 mg/kg, respectively) followed by Caliph (253 and 15 mg/kg, respectively). In the absence of P. medicaginis, Jemalong and Paragosa showed highest and lowest coumestrol (137 and 0 mg/kg, respectively). 4′-O-methylcoumestrol was not produced in disease-free plants, but coumestrol was. Disease incidence and severity on leaves and on petiole/stems, and consequent leaf yellowing severity ranged from 5%–98.7%, 0%–100%, 4.4%–98.7%, 1.7%–100%, and 0%–85%. Sava, Paraponto, Harbinger, and Serena were most susceptible, while Tornafield and Caliph were least susceptible. There was significant overall positive correlation of disease incidence/severity factors across cultivars (p < 0.01) with both coumestrol and 4′-O-methylcoumestrol. Jemalong was least responsive and Paragosa and Sava most responsive to coumestrol production following P. medicaginis inoculation. Coumestrol in inoculated Paragosa increased to 373 mg/kg in comparison with 0 mg/kg in controls. These findings are of critical importance towards developing less disease-susceptible annual Medicago spp. producing less detrimental phytoestrogens. Least susceptible cultivars like Tornafield and Caliph can be used to manage yield loss, whilst least responsive cultivars to phytoestrogen production like Caliph also can help to reduce phytoestrogen production.     

Sex steroid level and sexual dimorphism expression of genes in gonads of the great sturgeon Huso huso Linneaus, 1758 during maturity developmental stages

Little is known about molecular mechanisms involved in gonad differentiation in sturgeon species. In non‐mammalian vertebrates, sox9, dmrt1, cyp17a1 and ar are male specific genes in testicular differentiation and are highly conserved. In order to understand the mechanism underlying testicular development in sturgeon, we investigated sex steroids level of 11‐ketotestosterone (KT) and testosterone (T) and relative expression of sox9, dmrt1, cyp17a1 and ar in great sturgeon gonads during different stages of sexual maturity. The results showed all studied genes had dimorphic patterns in males. In immature gonads (stage I), only cyp17a1 expressed in male gonads, while other genes did not express, and KT and T levels were low. Dmrt1 showed dimorphic expression pattern in male gonads at maturity stage II, III and IV. Furthermore, sox9 and ar mRNA presented significant dimorphic expression pattern in male gonads only at maturity stage 4. Plasma androgens levels were significantly higher in males compared to females during maturity stages II, III and IV. The results showed that among these four genes, only cyp17a1 expressed in male gonads at maturity stage I (immature), suggesting that this gene may be applicable as a sex marker in recently differentiated male great sturgeon. Sexually dimorphic patterns in other studied genes (sox9, dmrt1 and ar) suggesting that these genes may be important for testicular development and differentiation in premature great sturgeon. The obtained results provide a foundation for further research on sex differentiation and developing strategies for the sexing of sturgeon for aquaculture.     

Spirulina as a source of vitamin A

Experiments were carried out to assess spirulina fusiformis — a blue green algae as a source of vitamin A in rats. In one experiment, the control rats were fed synthetic vitamin A and the experimental rats spirulina as the sole source of vitamin A. The liver vitamin A concentration of spirulina-fed rats of both sexes was found to be significantly higher than that of the control rats. In another experiment the absorption of carotenes from the solvent extract of spirulina and their availability (vitamin A value) as judged by the levels of vitamin A and carotene in plasma and liver were compared with those of synthetic -carotene or vitamin A in male rats. The absorption of -carotene from spirulina extract tended to be lower than that of crystalline -carotene at doses of 550 and 1100 g of -carotene. The difference became insignificant at lower -carotene dose of 275 g.Spirulina carotene-fed rats did not show a strict dose related increase in the liver or serum vitamin A concentration. The liver vitamin A storage and plasma levels of vitamin A of spirulina carotene-fed rats was much hither than expected. The results of the two studies reported suggest that the algae spirulina can be a valuable source of vitamin A.     

Carbon potentials of different biochars derived from municipal solid waste in a saline soil

There are numerous studies conducted on biochar for its carbon (C) sequestration potential;however,there are limited studies available on the behavior of salt-affected soils related to biochar application.Therefore,more studies are needed to elucidate the mechanisms through which biochar affects saline soil properties.In this study,biochars were produced from solid waste at pyrolysis temperatures of 300,500,and 700?C (BC300,BC500,and BC700,respectively)and applied to a saline soil to evaluate their impacts on soil carbon dioxide (CO₂) efflux,C sequestration,and soil quality.A soil incubation experiment lasting for 107 d was conducted.The results showed that soil CO₂ efflux rate,cumulative CO₂ emission,active organic C (AOC),and organic matter (OM)significantly increased with BC300 application to a greater extent than those with BC500 and BC700 as compared to those in the no-biochar control (CK).However,soil C non-lability did not significantly increase in the treatments with biochars,except BC700,as compared to that in CK.Besides improving the soil quality by increasing the soil AOC and OM,BC300 showed positive impacts in terms of increasing CO₂ emission from the saline soil,while BC500 and BC700 showed greater potentials of sequestering C in the saline soil by increasing the soil non-labile C fraction.The recalcitrance index (R50) values of BC500 and BC700 were>0.8,indicating their high stability in the saline soil.It could be concluded that biochars pyrolyzed at high temperatures (?500?C)could be suitable in terms of C sequestration,while biochars pyrolyzed at low temperatures (?300?C) could be suitable for improving saline soil quality.     

Marine Natural Products: Promising Candidates in the Modulation of Gut-Brain Axis towards Neuroprotection

In recent decades, several neuroprotective agents have been provided in combating neuronal dysfunctions; however, no effective treatment has been found towards the complete eradication of neurodegenerative diseases. From the pathophysiological point of view, growing studies are indicating a bidirectional relationship between gut and brain termed gut-brain axis in the context of health/disease. Revealing the gut-brain axis has survived new hopes in the prevention, management, and treatment of neurodegenerative diseases. Accordingly, introducing novel alternative therapies in regulating the gut-brain axis seems to be an emerging concept to pave the road in fighting neurodegenerative diseases. Growing studies have developed marine-derived natural products as hopeful candidates in a simultaneous targeting of gut-brain dysregulated mediators towards neuroprotection. Of marine natural products, carotenoids (e.g., fucoxanthin, and astaxanthin), phytosterols (e.g., fucosterol), polysaccharides (e.g., fucoidan, chitosan, alginate, and laminarin), macrolactins (e.g., macrolactin A), diterpenes (e.g., lobocrasol, excavatolide B, and crassumol E) and sesquiterpenes (e.g., zonarol) have shown to be promising candidates in modulating gut-brain axis. The aforementioned marine natural products are potential regulators of inflammatory, apoptotic, and oxidative stress mediators towards a bidirectional regulation of the gut-brain axis. The present study aims at describing the gut-brain axis, the importance of gut microbiota in neurological diseases, as well as the modulatory role of marine natural products towards neuroprotection.     

In vivo evaluation of gelatin/hyaluronic acid nanofiber as Burn-wound healing and its comparison with ChitoHeal gel

The study aims at performing a comparative assessment of two types of burn wound treatment. The present study was designed to prepare crosslinked and blended two natural polymers nanofiber scaffolds using gelatin (GE) and hyaluronic acid (HA). The GE/HA composite nanofibrous membranes with varied GE/HA weight ratio have also been successfully fabricated by an electrospinning method. The average diameter of GE/HA fibers was in the range of 20 to 150 nm. In vivo efficacy was also investigated based on a deep second degree burns model for Wistar rats. At 14 days post-operation, the dermal defect basically recovered its normal condition. A percentage of wound closure of GE/HA composite nanofibrous membranes and ChitoHeal gel reached up to 81.9 % and 77.8 % respectively, compared with 65 % of the untreated control (p<0.05). Also, histological parameters were assessed on postoperative day 7 and 14. The results of in vivo experiments showed that more epidermis was formed in the gel and scaffold groups compared to the control group. The numbers of inflammatory cells in these two groups were also smaller as compared with the control group, which could well be the reason for the delayed healing in the control group.