Low Content Research Articles

Improving the morphology of terrace-like transfer film to reduce wear rate of graphite/PTFE composites via filling low content silica

Purpose The purpose of this paper is to fill low content of silica to improve the wear resistance of graphite/polytetrafluoroethylene (PTFE) composites, and to discuss the effect of low content of silica on the morphology of terrace-like transfer film. Design/methodology/approach The tribological properties of silica/graphite/PTFE composites were tested by rotating pin-on-disk friction and wear tester, and the morphology of terrace-like transfer film was observed by 3D laser scanning microscope and quantitatively analyzed through the multi-Gaussian function linear combination model. Findings The results showed that adding 3 wt.% silica in graphite/PTFE composites can reduce the wear rate by 87%. More importantly, the morphology of terrace-like transfer film changed significantly after filling a small amount of silica, including the increase of the number of layers and the coverage rate of transfer film. Originality/value This work is of great significance for further understanding the transfer film and achieving its morphology control to optimize the wear of high performance PTFE composites.

Conspicuous parasite modifies appearance and energetics of a marine copepod

Abstract Parasitism is an important driver of ecosystem processes. Copepods are fundamental trophic links in marine food webs and harbour many microeukaryotic parasites, but unreliable access to infected individuals limits quantitative studies of parasite infection costs. Calanus spp., (helgolandicus or finmarchicus), infected with the Yellow-Hyphal Parasite become pigmented and are found near the surface, suggesting predator-mediated dispersal. Conventional markers prevented phylogenetic inference but confirmed that the parasite is not Ichthyophonus hoferi, as previously thought. We identified the pigments, quantified the pigment content and respiration rate, and derived stable isotope signatures of infected and uninfected Calanus spp. to examine costs of infection. We found that the pigments were astaxanthin and β-carotene, associated with the host and parasite, respectively. Parasitized hosts had increased astaxanthin content, reduced respiration rate, and lower lipid content. Ultrastructure imaging revealed parasitic cells associated with lipids in the haemocoel. The changes to host phenotype have detrimental impacts on energetics and the ecology of Calanus. We discuss the role of pigments in parasite-host interactions and suggest that the parasite produces β-carotene pigment for its physiological benefits. The trade-off between physiological benefits of pigments and conspicuousness for parasites is relevant in zooplankton-host systems, as zooplankton rely heavily on transparency for survival.

Mechanisms of calcium-induced protection against lead toxicity in Ulmus umbraculifera L.: a physiological and biochemical perspective.

Lead (Pb) is a toxic stressor in the soil, which affects plant morphological and physiological events differently. A pot study was initiated to characterize the effect of calcium (Ca) application (20 and 40 mM) on Ulmus umbraculifera L. under Pb treatment (200 and 400 µM). The results revealed that higher levels of Pb significantly reduced plant height (48.3%), total dry weight (44.7%), leaf area index (45%), chlorophyll a (53.7%), chlorophyll b (51.4%), carotenoids (37.8%), and Fv/Fm ratio (20.4%) compared to untreated plants. However, the Ca application improved the aforementioned physiological features. Additionally, Pb toxicity disrupted oxidative status in the plants by increasing malondialdehyde (MDA), methylglyoxal, superoxide anion, and H₂O₂, which also induced the activities of SOD, GR, APX, and CAT. In contrast, Ca decreased MDA, methylglyoxal, superoxide anion, and H₂O₂ by enhancing SOD, CAT, GR, and APX activities compared to the control. Notably, ascorbate (AsA), dehydroascorbic acid (DHA), glutathione (GSH), oxidized glutathione (GSSG) levels, and AsA-DHA and GSH-GSSG ratios changed significantly with Pb and Pb + Ca treatments. According to our findings, monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glyoxalase (Gly) I, and Gly II activities increased with Pb treatment; however, Ca application further promoted their activities. Furthermore, Pb treatment significantly suppressed the uptake of mineral nutrients and increased Pb accumulation, whereas Ca application improved the uptake of these elements and lowered Pb content. These observations confirmed that the positive effects of Ca application on photosynthetic efficiency, nutrient absorption, and enzymatic and non-enzymatic antioxidants enhanced plant tolerance under Pb toxicity.

New grape varieties descending from Monastrell characterised by their low sugar and high polyphenolic content

New grape varieties descending from Monastrell characterised by their low sugar and high polyphenolic content

How to Keep Lactose Avoiders Healthy

A large portion of the world’s population has lactose intolerance. Fundamentally, this condition occurs when the small intestine does not produce enough of the lactase enzyme, which digests the disaccharide lactose in milk. Lactose avoiders might unconsciously decide to limit or exclude milk and dairy products from their diets. This group includes people with lactose intolerance, people with an allergy to milk protein, vegans, and those expressing personal preferences. Lactose avoiders are often self-reported as being milk intolerant. In this review, specific amounts of lactose in different types of milk and milk products are presented. The amounts of micro- and macronutrients in them are compared with the daily requirements established by accepted sources. Foods are suggested that can play vital roles in permanently avoiding lactose-containing dairy products, for example, brussels sprouts, as a good source of vitamin B1; kale, as a source of vitamin K; and cereals at breakfast for vitamin B6. Attention is paid to mature cheeses as they are extremely beneficial for health due to their rich vitamin and elemental compositions, and they are also suitable for people with lactose intolerance due to their low lactose content. This information is rarely provided on packaging. In addition, the current state of labeling for the presence of lactose in food and pharmaceutical products is discussed. The term “hidden lactose” is introduced to include added lactose in unexpected foods, drinks, and even medicines.

Assessment of the use of biochar from the slow pyrolysis of walnut and almond shells as an energy carrier

ABSTRACT This study explores the energy applications and combustion kinetics of biochar produced from walnut and almond shells through pyrolysis. Using macro-thermogravimetric analysis at heating rates of 10, 15, and 20 K min−1, a multi-step mechanism involving two parallel reactions was used to model thermal decomposition. Bioenergy indices revealed that walnut shell-based biochar (WSB) produced at 773 K and 873 K displayed superior biofuel potential due to its high energy density and low ash content, while almond shell-based biochar (ASB) at 673 K demonstrated the best overall bioenergy performance. Among the tested heating rates, 15 K min−1 provided optimal results for ignition, combustion, and burnout indices, with WSB showing the highest overall combustion performance. Kinetic analysis using the Coats-Redfern method demonstrated the highest R2 values and minimized RMSE and SSE. The activation energy for the first pseudo-component ranged from 54.91 to 129.84 kJ mol−1 for ASB and from 61.71 to 141.85 kJ mol−1 for WSB. For the second pseudo-component, the activation energy ranged from 25.21 to 159.32 kJ mol−1 for ASB and 25.63 to 96.25 kJ mol−1 for WSB. These findings emphasize the potential of WSB and ASB biochar for bioenergy applications, with WSB exhibiting the best combustion characteristics.

Recycled Aggregate Concrete with Industrially Pre-carbonated Recycled Concrete Aggregates and Low Clinker Content

Recycled Aggregate Concrete with Industrially Pre-carbonated Recycled Concrete Aggregates and Low Clinker Content

Improving the biodiesel production in the marine diatom Thalassiosira pseudonana cultivated in nutrient deficiency and sewage water.

The use of microalgae as a feedstock in biofuel production is highly encouraging. The marine diatom in this study, Thalassiosira pseudonana, was used as a test organism to evaluate the impact of nitrogen or phosphorus limitation and sewage water on improving biodiesel production. The growth rate is more affected in cultures without phosphorus by 41.8% lower than in control and the highest dry weight estimated in control. The cellular dry weight significantly increased in cultures treated with mix1 and mix2 wastewater compared to the control cultures. Chlorophyll a content decreased in the absence of nitrogen and phosphorous and in sewage water cultures. Lipid content in algal cultures without nitrogen or phosphorus and in sewage water accumulated nearly twice as much lipid content in synthetic medium. T. pseudonana showed high FAME contents; the two most abundant fatty acids, stearic acid (C18:0) and palmitoleic acid (C16:1), in the algal extracts revealed that T. pseudonana was predominantly composed of these fatty acids. T. pseudonana grown in nitrogen or phosphorus-deficient conditions exhibited an extreme percentage of saturated fatty acids (SFAs) by 87.38% and 85.47%, respectively, of the total fatty acids (TFAs). More importantly, the low polyunsaturated fatty acid content in oils indicates a high cetane number, low iodine value, and low corrosion for biodiesel quality indicators. Producing biodiesel that closely meets worldwide biodiesel requirements (ASTM D6751 and EN 14214) is the goal of this work, which shows that growing T. pseudonana under nutrient limitations leads to algal metabolism in that direction.

Magnesium Stearate Fatty Acid Composition, Lubrication Performance and Tablet Properties

Magnesium stearate (MgSt) is a common tablet lubricant. As variations in MgSt properties are known to influence tablet attributes, the impact of MgSt fatty acid composition, particularly the significance of the stearate and palmitate contents, and its effects on tablet properties warrant further investigation. This study investigated the effect of MgSt with different stearate and palmitate contents but comparable physical properties (e.g. particle size, crystallinity, specific surface area and morphology) on lubrication performance and resulting tablet quality attributes, including mechanical strength, disintegratability and drug release. The influence of MgSt concentration and blending duration on the resulting tablet properties was also examined. Tablets produced using the lower stearate content MgSt had slightly higher tensile strength. The effect of MgSt stearate content was more apparent in the disintegration time and drug release, whereby MgSt of lower stearate content resulted in tablets with longer disintegration time and slower drug release. The lower stearate content also resulted in a lower lubrication performance, leading to a lesser reduction in tablet ejection force. As expected, a longer blending time of the tablet formulation blend with MgSt yielded tablets with reduced tensile strength, shorter disintegration time and slower drug release. Tablets with higher MgSt concentration showed a greater reduction in tensile strength, longer disintegration time and faster drug release. The study findings reinforced observations by other researchers and provided a better understanding of the fatty acid composition effects of MgSt on lubrication performance and the resulting tablet properties.Graphical

Effect of patulin on the growth and nutrient composition of black soldier fly larvae

Abstract Black solider fly (BSF, Hermetia illucens) is a common insect in most part of North America, Europe, and Asia, and it is one of the most promising alternative protein sources for animal consumption. BSF can be fed on food waste and agricultural byproducts, which are usually contaminated with mycotoxins. Therefore, it is important to study the fate of mycotoxins in BSF and how mycotoxins will affect the growth and nutrient composition of BSF. Patulin is one of the major mycotoxins found in rotten fruits and consumption of patulin contaminated food can cause both long term and short-term health problems in both human and livestock. In this study clean and patulin spiked apple puree were provided to 50 three days old black soldier fly larvae (BSFL) for 3, 6, 9 and 17 days. Patulin bioaccumulation and degradation by BSFL, survival rate, weight gain and nutrient composition of BSFL were evaluated. During the treatment period, no patulin bioaccumulation was found in BSFL. BSFL was able to degrade patulin and convert patulin into (E)-ascladiol. By day 17, BSFL degraded 89.7% of patulin, 5.7% of patulin was converted into (E)-ascladiol, and 10.3% of patulin remained in its original form. While patulin treatment led to lower biomass and growth rate in BSFL, greater protein content and lower lipid content was observed in patulin treated BSFL. Thus, we conclude that BSFL do not accumulate patulin, and it is able to degrade patulin and converts patulin into its derivatives. The applied patulin negatively affects the development of BSLF resulting in lower biomass, growth rate and lipid content, but it induces higher protein content in BSFL.

Use of lignocellulose-degrading enzyme bio-cemented soils in the construction industry

In their activity, termites break down biomass into glucose, forming cementitious compounds. This results in rainfall-resistant mounds for their shelters, which interests the construction industry. This study explored the potential application of the abundant naturally bio-cemented termite mound soils in highway construction. Experimental investigations compared these mound soils to surrounding soils, revealing that mound soils are 68.2% finer in particle size distribution and have 81.4% lower organic content. Atterberg limits indicated 14.6% higher plasticity and a 5.3% increase in specific gravity for mound soils. Atomic Absorption Spectroscopy (AAS) showed no significant difference in chemical composition. Proctor tests indicated that the compaction characteristics of the soils were comparable, confirming their engineering viability without modifications. Mound soils exhibited a twofold increase in Unconfined Compressive Strength (UCS) and a 33.9% increment in California Bearing Ratio (CBR) strength. One-way ANOVA tests confirmed these differences with p-value ranges of 0.0056-0.0361 below the 0.05 significance threshold. The study advocates utilising eco-friendly naturally bio-cemented mound soils in highway construction, meeting minimum standards. Mound soils from one acre can construct up to 2,500m highway, optimising resource use, promoting sustainability by repurposing natural materials, and significantly reducing carbon emissions. Further research on soil improvement using lignocellulose-degrading enzymes is recommended.

Nitrogen Storage in Rice: Analysis of Physical Quality by Respiration, Weight, and Storage According to Nitrogen Ratio

Various studies have been conducted to minimize the damage and loss of stored grain. For safe storage, the moisture content must be reduced, or respiration must be suppressed. In this study, grain respiration rates were analyzed under various nitrogen atmospheric conditions, and the quality of stored rice was evaluated. As the nitrogen content of the storage space increases, the respiration rate of the grain decreases accordingly. In this study, the effect of the modified atmospheric nitrogen concentration on reducing respiration was determined. When predicting weight loss due to respiration, low moisture content, and high nitrogen concentration could reduce loss. Quality analysis was performed to compare different respiration rate conditions and showed that lower oxygen concentration and moisture content were associated with safer storage. Our results indicate that changes in atmospheric conditions depending on climate and storage conditions can be considered for the safe storage of harvested rice.

Utilising brewer’s spent grain as a cost-effective feed formula for sustainable house cricket (Acheta domesticus) rearing

Abstract This study investigates the potential of brewer’s spent grain (BSG) as a cost-effective alternative to soybean meal in the diets of house crickets (Acheta domesticus) to enhance sustainable cricket rearing. BSG, a by-product of the brewing industry, was chosen due to its local availability and high protein content (38%). Here, the impacts of varying levels of BSG substitution (0%, 10%, 20% and 30%) on the growth performance, nutrient utilisation, chemical composition, and volatile compound profiles of crickets over a 45-day period was assessed. Crickets were reared under controlled conditions and divided into five groups, each receiving one of the experimental diets. Growth performance parameters, including body weight, average daily gain, and feed conversion ratio, were measured. Chemical analysis of the crickets and their diets was conducted, focusing on protein efficiency ratio, apparent dry matter digestibility (ADMD), and nitrogen retention. Volatile compounds were identified using gas chromatography-mass spectrometry. Crickets fed BSG diets exhibited higher protein deposition and lower fat content compared to those on a commercial diet, suggesting BSG’s potential to improve protein quality while reducing fat accumulation. ADMD was also higher in BSG-fed crickets, likely due to the prebiotic effects of components such as β-glucans and arabinoxylans. Additionally, the inclusion of BSG up to 30% in cricket diets reduced production costs by up to 29% compared to a commercial diet. Volatile compound analysis revealed that crickets fed BSG diets produced different odour profiles, with 2-heptanone, a compound with a fruity aroma, detected only in BSG-fed crickets. These findings suggest that BSG is a viable and sustainable ingredient for cricket feed, offering both economic and nutritional benefits while also influencing the sensory characteristics of crickets. Further research is recommended to optimise BSG inclusion levels and explore its broader applications in insect and animal farming.

PVDF‐based nanocomposite coatings with superhydrophobic and antibacterial properties on stainless steel surfaces

AbstractIn this study, using a spray‐coating technique, stainless steel surfaces were coated with polyvinylidene fluoride (PVDF) and carbon soot nanoparticles. We imparted various surface properties onto the coatings' surfaces by varying the nanoparticle content and the preparation method. The main aim was to develop antibacterial surfaces by inducing superhydrophobic properties in stainless steel surfaces. In a one‐step preparation method, 5% and 10% of nanoparticles were insufficient to achieve superhydrophobicity, whereas 20% significantly increased the water contact angle to 153°. Morphological evaluations revealed the formation of a nano‐scale structure, which also led to a staggering antibacterial rate of 99.5% against Listeria monocytogenes. Using a two‐step preparation, soot nanoparticles were localized at the coating's top layer, which led to superhydrophobicity at a lower nanoparticle content (10%). However, the bacterial adhesion study showed a lower antibacterial rate (~93%). The difference in bacterial adhesion results was explained by various roughness structures according to the atomic force microscopy results. The developed system has a promising potential to be used as self‐cleaning and antibacterial coatings in the medical and food industries.Highlights Stainless steel surfaces were coated with PVDF and carbon soot nanoparticles Imparted various surface properties onto the coatings' surfaces Developed antibacterial surfaces by inducing superhydrophobic properties Using a two‐step, soot nanoparticles were localized at the coating's top layer Bacterial adhesion study showed a lower antibacterial rate (~93%).

Investigation of the Fermentation Process of Moringa oleifera Leaves and Its Effects on the Growth Performance, Antioxidant Capacity, and Intestinal Microbiome of Procambarus clarkii

Moringa oleifera is renowned for its high antioxidant activity. However, few studies have been conducted on its effects on aquatic animals. The aim of this experiment was to investigate the optimal fermentation process of M. oleifera leaves and to evaluate the effects of fermented M. oleifera leaves on crayfish (9.11 ± 0.3 g) in terms of growth performance, antioxidant capacity, and gut microbiological parameters. By optimizing the fermenting material/water ratio, fermentation time, temperature, and strain, the optimal fermentation conditions of a 10% water ratio + 48 h + 30 °C + inoculation with 2% B. amyloliquefaciens (107 CFU mL−1) were obtained. These conditions resulted in notable increases in the contents of the total protein, total phenols, flavonoids, and amino acids (p < 0.05) while also leading to a notable decrease in the content of tannins in contrast to those of unfermented M. oleifera leaves (p < 0.05). The fermented M. oleifera (FMO) leaves were incorporated at five concentrations, including 0% (control (CT)), 0.25% (0.25FMO), 0.5% (0.5FMO), 1% (1FMO), and 2% (2FMO). The results showed that the 1FMO group performed better in terms of the final body weight (FBW), weight gain rate (WGR), and specific weight gain rate (SGR) compared with the CT group (p < 0.05). In addition, amylase and lipase activities were significantly higher in the 1FMO and 2FMO groups compared with the other groups (p < 0.05). The fermented M. oleifera leaves significantly increased the catalase (CAT) activity in the crayfish (p < 0.05). The superoxide dismutase (SOD) activity was significantly increased in the 0.25FMO, 1FMO, and 2FMO groups, and the malondialdehyde (MDA) content was significantly decreased while the glutathione peroxidase (GSH-PX) content was significantly increased in the 0.5FMO, 1FMO, and 2FMO groups (p < 0.05). Furthermore, the 1FMO group was observed to significantly increase the abundance of Firmicutes while simultaneously reducing the abundance of Aeromonas (p < 0.05) and adjusting the structure of the intestinal microbiome. In conclusion, this study established the optimal fermentation conditions for M. oleifera and obtained a product with high nutrient and low tannin contents. Furthermore, the incorporation of 1% FMO was demonstrated to facilitate growth, enhance the antioxidant capacity, and optimize the gut microbiology in crayfish.

New Materials from the Integral Milk Kefir Grain Biomass and the Purified Kefiran: The Role of Glycerol Content on the Film’s Properties

Microbial exopolymers are gaining attention as sources for the development of biodegradable materials. Milk kefir, a fermented dairy product produced by a symbiotic community of microorganisms, generates milk kefir grains as a by-product, consisting of the polysaccharide kefiran and proteins. This study develops two materials, one from whole milk kefir grains and another from purified kefiran. Film-forming dispersions were subjected to ultrasonic homogenisation and thermal treatment, yielding homogeneous dispersions. Kefiran dispersion exhibited lower pseudoplastic behaviour and higher viscous consistency, with minimal effects from glycerol. Both films exhibited continuous and homogeneous microstructures, with kefiran films being transparent and milk kefir films displaying a yellowish tint. Analysis revealed that milk kefir films comprised approximately 30% proteins and 70% kefiran. Kefiran films demonstrated stronger interpolymeric interactions, as evidenced using thermogravimetric and mechanical tests. Glycerol increased hydration while decreasing thermal stability, glass transition temperature, elastic modulus, and tensile strength in both films. However, in kefiran films, elongation at the break and water vapour permeability decreased at low glycerol content, followed by an increase at higher plasticiser contents. This suggests an unusual interaction between glycerol and kefiran in the absence of proteins. These findings underscore differences between materials derived from the whole by-product and purified kefiran, offering insights into their potential applications.

Molecular Mechanism of Physical and Mechanical Improvement in Graphene/Graphene Oxide-Epoxy Composite Materials.

The performance provided by graphene (Gr) and graphene oxide (GO) additives can be improved by achieving strong adhesion and uniform dispersion in the epoxy resin matrix. In this study, molecular modeling and simulation of DGEBA/DETA based epoxy nanocomposites containing Gr and GO additives were performed. Density functional theory and molecular dynamics simulations were used to investigate interfacial interaction energies and Young's Modulus. Improvement in the interaction energies was studied by controlling the epoxy:hardener ratio, type and the number of oxygen-containing functional groups on the GO, the mass percentage of Gr/GO filler in the epoxy matrix, size and dispersion of GO in the cell. It was demonstrated that functional groups with up to 10 % oxygen content in GO significantly increase interfacial interaction energy for large size Gr/GO. Increasing DETA type amine ratio in the preparation of epoxy polymers increases the interaction energy for high oxygen content while decreasing the interaction energy for low oxygen content in GO for small size GO with edge functional groups. The performance of material dramatically decreased even at high DETA hardener and high GO mass percentages when the aggregation factor of Gr/GO was included in simulations that explain lower Gr/GO percentages in the experimental studies.

The Effect of Cryogenic Treatment on a High Co Bearing DIN 1.2888 Steel Used as Die in Hot Forging Process

Abstract Hot work steels used as dies in metal forming processes must endure harsh conditions, typically achieved through a martensitic structure. However, retained austenite can persist after martensitic transformation, negatively impacting mechanical properties. Cryogenic treatment (CT) refines martensite, reduces retained austenite, and increases fine carbide density, thus enhancing performance. DIN 1.2888, a hot work tool steel with high cobalt content (~10%) and low carbon content (~0.2%), is less studied concerning the effects of CT. The objective of this study was to investigate how cryogenic treatment affects the mechanical and microstructural properties of DIN 1.2888 steel. Samples underwent conventional heat treatment (HT) and CT at -100, -140, and -180°C for 6 hours, followed by double tempering. Various analytical methods, including X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), and Vickers Microhardness tests, were used to examine the samples. Wear mechanisms were evaluated through pin-on-disc tests under different loads, and impact toughness was measured both at room temperature and the working temperature of dies (350°C). Results indicated that lowering the cryogenic treatment temperature resulted in a slight increase in hardness values from 507HV for the heat-treated sample to 529HV for the sample treated at -180°C. Additionally, the impact toughness improved significantly, with values rising from 12.35J for the heat-treated sample to 23.44J at 350°C for the cryogenically treated sample at -180°C. Wear rates also decreased by approximately 50%, particularly at higher cryogenic treatment temperatures. The improvement in wear resistance was attributed to finer carbide precipitation and a more homogeneous distribution of carbides. These findings suggest that deep cryogenic treatment has a positive effect on DIN 1.2888 steel by decreasing retained austenite and increasing fine carbide density, leading to enhanced mechanical properties and extending the lifespan of the steel in die applications.

Prickly postglacial pioneers: freshwater plankton community composition influences fatty acid desaturase (FADS2) copy number in southern Greenland threespine sticklebacks

The adaptation of marine fish to freshwater environments includes prodigious examples of rapid evolution.Given the scarcity of ω‐3 long‐chain polyunsaturated fatty acids (LC‐PUFA) in freshwater, we expect selection to be strong on fish transitioning to freshwater habitats and yet the underlying ecological causes of genomic and phenotypic differentiation are poorly understood for traits associated with lipid content and composition. Threespine stickleback Gasterosteus aculeatus have repeatedly colonized, and adapted to, freshwater habitats across the Northern Hemisphere. These freshwater populations often show elevated copy number of the fatty acid desaturase 2 gene (FADS2), which increases the biosynthetic capacity of LC‐PUFA. The starkly lower content of LC‐PUFA in freshwater compared to marine prey, especially docosahexaenoic acid (DHA), likely imposes strong positive selection on freshwater fish for either increased biosynthesis or greater dietary acquisition of LC‐PUFA. The recently colonized and relatively undisturbed threespine stickleback populations in postglacial coastal lakes of southern Greenland offer an exceptional opportunity to study how variation in the copy number of FADS2 is related to abiotic and biotic conditions of lakes and their morphometry. As expected, given its position on the stickleback X chromosome, we found strong sexual dimorphism in FADS2 copy number in all populations (19 freshwater, 1 marine and 1 brackish), and an increased dimorphism in some freshwater populations. We also found that FADS2 copy number was negatively correlated, for both males and females, with the abundance of copepods, which are a DHA‐rich food source in the zooplankton community. Overall, our results suggest that the prey community context of lakes might influence the process of metabolic adaptation of marine fish colonizing freshwater ecosystems.

The Optimum Mixed Cropping Ratio of Oat and Alfalfa Enhanced Plant Growth, Forage Yield, and Forage Quality in Saline Soil

The forage shortage is more aggravating than ever before, with husbandry development accelerating and meat and dairy product demand increasing. Salinized soils are important reserve land encouraged to be used for forage production in China. However, the salt-tolerant cultivation techniques for forage crops are still inadequate. Therefore, a field experiment was conducted to study the effects of the mixed cropping ratio of oat and alfalfa on plant growth and physiological traits, forage yield, and forage quality in saline soils. Oat (Avena sativa L.) variety of Canadian Monopoly and alfalfa variety of WL525HQ were used, and five mixed cropping ratios (T1 = 100% oat + 0% alfalfa, CK, T2 = 75% oat + 25% alfalfa, T3 = 50% oat + 50% alfalfa, T4 = 25% oat + 75% alfalfa, and T5 = 0% oat + 100% alfalfa) were evaluated. The results showed that plant height, chlorophyll, soluble sugar, starch, antioxidant enzymes, and crude fat were increased firstly and then decreased prominently with decreased oats and increased alfalfa sowing rate; the maximum values showed under T2 but the minimum value under T5 at evaluated growth periods. On the contrary, malondialdehyde and acid detergent fiber were significantly decreased and then increased; the lowest contents were recorded under T2 and highest under T5. Furthermore, the relative growth rate, forage yield, neutral detergent fiber, and crude ash were decreased prominently with decreased oats and increased alfalfa sowing rate, and the highest and lowest values showed under T1 and T5, respectively. Oppositely, the contents of sucrose, proline, N, P, K, relative feeding value, and crude protein were all increased, with the highest contents generated under T2 and the lowest under T1. On the whole, the mixed cropping treatment of T2 showed the best performance in improving both biomass yield and forage quality by enhanced antioxidant enzyme activity, osmotic regulatory substances, and nutrient uptake and utilization. Therefore, this study indicates that 75% oat mixed cropping with 25% alfalfa can be recommended as a salt-tolerant cultivation technique for forage high-yield and high-quality production in moderately saline soil.