Animal Systems Research Articles

Antioxidant Potential of Exosomes in Animal Nutrition.

This review delves into the advantages of exosomes as novel antioxidants in animal nutrition and their potential for regulating oxidative stress. Although traditional nutritional approaches promote oxidative stress defense systems in mammalian animals, several issues remain to be solved, such as low bioavailability, targeted tissue efficiency, and high-dose by-effect. As an important candidate offering regulation opportunities concerned with cellular communication, disease prevention, and physiology regulation in multiple biological systems, the potential of exosomes in mediating redox status in biological systems has not been well described. A previously reported relationship between redox system regulation and circulating exosomes suggested exosomes as a fundamental candidate for both a regulator and biomarker for a redox system. Herein, we review the effects of oxidative stress on exosomes in animals and the potential application of exosomes as antioxidants in animal nutrition. Then, we highlight the advantages of exosomes as redox regulators due to their higher bioavailability and physiological heterogeneity-targeted properties, providing a theoretical foundation and feed industry application. Therefore, exosomes have shown great potential as novel antioxidants in the field of animal nutrition. They can overcome the limitations of traditional antioxidants in terms of dosage and side effects, which will provide unprecedented opportunities in nutritional management and disease prevention, and may become a major breakthrough in the field of animal nutrition.

Towards Understanding Cat Vocalizations: A Novel Cat Sound Classification Model Based on Vision Transformers

Animal sound perception systems are highly developed compared to humans, crucial for survival in natural environments, with some species possessing specialized sensory capabilities such as vision, hearing, touch, and environmental awareness. Understanding animal sounds not only aids in their own communication and survival but also benefits humans in various fields including security, natural disaster prediction, ecological research, bioacoustics, precision agriculture, and search and rescue operations. Motivated by this fact, this study investigated the classification of cat sounds using deep learning models based on Vision Transformer (ViT) and Convolutional Neural Network (CNN) architectures. Cat vocalizations, represented as mel-spectrograms, were classified using models trained on a diverse dataset of cat sounds. Experimental results demonstrated the superiority of the proposed model based on Microsoft’s BERT Pre-Training of Image Transformers (BEiT) over the state-of-the-art as it obtained an exceptional accuracy of 96.95%. Additionally, it was observed that the proposed models based on ViT outperformed CNN-based models, highlighting the efficacy of transformer architectures in capturing complex patterns within audio data. These findings underscore the potential of ViT architectures in decoding animal communication systems and advancing wildlife conservation efforts.

Lessons for the Future of NAMs from History, Philosophy and Social Studies of Science.

This paper explores what we can learn from the humanities and social sciences about how standards operate in and around science, in order to understand more about how 'the gold standard' can be shifted away from the use of animals in research and testing, and toward New Approach Methodologies (NAMs). These fields allow us to consider potential futures of NAMs as alternatives, replacements, or complements to animal use in testing and research. As we demonstrate, the questions that we pose and how they are framed are as important as the answers that result. Rather than asking how to 'redefine the gold standard', norms and expectations for NAMs must be actively debated and transparently defined. These considerations would be based, in part, on what has been learned in the past from non-human animal models and systems, but also use the norms within the fields from which the NAMs derive in light of the rich broader contexts within which they are being developed. As we argue, notions such as 'a gold standard' are limited and must be replaced by contextualised standards that depend on the scientific, sociocultural and other factors that contribute to our understanding of a particular method (new or otherwise) as 'good' for a particular purpose.

Alfalfa‐bermudagrass mixtures managed under contrasting harvest strategies in the southeastern US

AbstractThe incorporation of dual‐purpose alfalfa (Medicago sativa L.) cultivars into bermudagrass (Cynodon spp.) is a viable option to extend the grazing season in Southern forage systems. However, data are limited on which harvest management strategy (HMS) optimizes the use of alfalfa‐bermudagrass (ABG) mixtures in the Southern US. A two‐year study evaluated ABG mixtures under three HMS [cut only (CO), graze only (GO), or cut and graze (CG)].in Headland, AL and Tifton, GA. Alfalfa‐bermudagrass mixtures utilized in this evaluation were ‘Bulldog 805’ alfalfa that was interseeded into ‘Tifton 85’ bermudagrass. Treatments were evaluated for forage, animal, and total system performance. Herbage accumulation varied by year and location (p < .01), but the number of harvests ultimately determined the total forage produced. Forage allowance was never limiting but did differ among treatments at Tifton, GA (p = .02). The CG HMS allowed for similar daily (p > .06) and liveweight gains (p > .56) on fewer days of grazing as compared to the GO treatments. The greater alfalfa percentage in the CG HMS translated to greater total digestible nutrients (TDN) and crude protein (CP), though not always statistically different. The CO HMS maximized system performance when evaluated for total gain (actual gains + predicted gains). However, the CG management allowed for more production opportunities across the season, thereby reducing economic risk. Future research should focus on evaluating the economic implications of introducing each HMS into ABG systems.

Toxicological properties of mixtures of binary silver-copper, silver-zinc, and copper nanoparticles on cell culture model and laboratory animals

The development, testing, and implementation of antimicrobial agents necessitates the determination of their toxicological characteristics. The objective of our research was to ascertain the direction and magnitude of the impact of experimental samples of disinfectants based on binary silver-copper, silver-zinc, and copper nanoparticles on biological entities of disparate levels of organization (cell culture, laboratory animals). The culture of calf coronary vessel cells (CVCs), 220 mature white laboratory rats, and 45 Chinchilla rabbits were used for the study. Mixtures of binary nanoparticles D1: MeNPs content – 5.4 mmol/L; D2: MeNPs content – 4.9 mmol/L were used as antimicrobial compounds. Toxic effects on cell culture were determined by the percentage of monolayer integrity, and biological effects in animals were determined by determining acute and subacute toxicity by clinical and biochemical parameters. The results of the culture studies demonstrated that the CC50 value of D2 was 6.2 times lower than that of D1, indicating a higher degree of cytotoxicity. No animal deaths were observed in the acute toxicity test (single intragastric administration to white rats at a dose of 30000 mg/kg body weight), which permitted the classification of the test samples as Class VI toxicity (relatively harmless) and Class IV hazardous (low-hazardous). When applied topically to rabbits' skin and mucous membranes, the experimental samples did not exhibit a pronounced irritant effect. A 30-day dermal application of the drugs to rats at doses of 0.5 and 5.0 mL/kg was conducted to determine the impact on hematological and biochemical parameters of a tenfold dose. Following the cessation of the administration of the aforementioned experimental disinfectant samples, the levels of all indicators were observed to return to the control levels within 14 days. The higher toxicity of the D2 drug for biological systems of different levels of organization, compared to the D1 drug, may be attributed to two factors: the higher concentration of AgNPs (2.4 times) and the potentiation of the toxic effect of two binary compounds (Ag-Zn and Ag-Cu) in its composition. Further research is needed to determine the biological impact of experimental samples of disinfectants based on silver, copper, and zinc metal nanoparticles on other functional systems of laboratory animals and the clinical and biochemical status of productive agricultural animals in production conditions.

Mechanical Nociception Assay in Drosophila Larvae.

The nervous system of animals can sense and respond to noxious stimuli, which include noxious thermal, chemical, or mechanical stimuli, through a process called nociception. Here, we describe a simple behavioral assay to measure mechanically induced nociceptive responses in Drosophila larvae. This assay tests larval mechanosensitivity to noxious force with calibrated von Frey filaments. First, we explain how to construct and calibrate the customizable von Frey filaments that can be used to deliver reproducible stimuli of a defined force or pressure. Next, we describe how to perform the mechanical nociception assay on third-instar larvae. Through comparison of the responses of genotypes of interest, this assay can be useful for investigation of molecular, cellular, and circuit mechanisms of mechanical nociception. At the molecular level, prior studies have identified the importance of sensory ion channels such as Pickpocket/Balboa, Piezo, dTRPA1, and Painless. At the cellular level, the class IV multidendritic arborizing (md-da) neurons are the main mechanical nociceptor neurons of the peripheral system, but class III and class II md-da have been found to also play a role. At the circuit level, studies have shown that mechanical nociception relies on interneurons of the abdominal ganglia that integrate inputs from these various md-da neuron classes.

Structural color in fruits: Biomaterials to inspire physical optics

This Tutorial introduces structural color in fruits as a phenomenon of diverse optical materials. Originally best known in abiotic materials and animals, structural colors are being increasingly described in plants. Structural colors have already inspired a variety of useful products, and plants are especially attractive as models to develop new bioinspired technologies thanks to the comparative ease of working with them compared with animal systems. Already, human-engineered structural colors modeled after plant cellulose-based architectures have shown promising applications in colorants and sensors. However, structural colors include a far broader group of materials and architectures beyond cellulose. Understanding the new and diverse structures that have recently been described in plants should provoke research into new bioinspired products based on plant optical structures and biomaterials. In this Tutorial, we focus on fruits as new structures have recently been discovered, leading to new opportunities for bioinspired technologies. We bring together a review of optical structures found in fruits from a physical optics perspective, with a consideration of each structure as an opportunity in bioinspired and biomimetic design.

Genetic variation in the brooding brittle-star: a global hybrid polyploid complex?

The widespread and abundant brooding brittle-star (Amphipholis squamata) is a simultaneous hermaphrodite with a complex mitochondrial phylogeography of multiple divergent overlapping mtDNA lineages, high levels of inbreeding or clonality and unusual sperm morphology. We use exon-capture and transcriptome data to show that the nuclear genome comprises multiple (greater than 3) divergent (π > 6%) expressed components occurring across samples characterized by highly divergent (greater than 20%) mitochondrial lineages, and encompassing several other genera, including diploid dioecious species. We report a massive sperm genome size in A. squamata, an order of magnitude larger than that present in other brittle-stars, and consistent with our SNP-based measure of greatly elevated ploidy. Similarity of these genetic signatures to well-known animal systems suggests that A. squamata (and related taxa) is a hybrid polyploid asexual complex of variable subgenome origins, ploidy and reproductive mode. We discuss enigmatic aspects of A. squamata biology in this light. This putative allopolyploid complex would be the first to be reported from the phylum Echinodermata.

Prospects of Electrocorticography in Neuropharmacological Studies in Small Laboratory Animals.

Electrophysiological methods of research are widely used in neurobiology. To assess the bioelectrical activity of the brain in small laboratory animals, electrocorticography (ECoG) is most often used, which allows the recording of signals directly from the cerebral cortex. To date, a number of methodological approaches to the manufacture and implantation of ECoG electrodes have been proposed, the complexity of which is determined by experimental tasks and logistical capabilities. Existing methods for analyzing bioelectrical signals are used to assess the functional state of the nervous system in test animals, as well as to identify correlates of pathological changes or pharmacological effects. The review presents current areas of applications of ECoG in neuropharmacological studies in small laboratory animals. Traditionally, this method is actively used to study the antiepileptic activity of new molecules. However, the possibility of using ECoG to assess the neuroprotective activity of drugs in models of traumatic, vascular, metabolic, or neurodegenerative CNS damage remains clearly underestimated. Despite the fact that ECoG has a number of disadvantages and methodological difficulties, the recorded data can be a useful addition to traditional molecular and behavioral research methods. An analysis of the works in recent years indicates a growing interest in the method as a tool for assessing the pharmacological activity of psychoactive drugs, especially in combination with classification and prediction algorithms.

Treatment of functional disorders of gastrointestinal tract of calves with complex phytomineral preparation

Significant economic losses due to diarrhoea morbidity in newborn young animals lead to a decrease in the profitability of the sector in the structure of agricultural production. Therefore, the purpose of this study was to create and investigate the therapeutic effect of application of complex phytomineral preparation using local components: opoka of Taskala deposit and decoction of camelthorn (Alhagi maurorum) for treatment of diarrhoea in calves. The therapeutic effect of the preparation was studied in the conditions of dairy farm in Kyzylorda region on 5-7-day-old calves. The effect of the preparation was studied in a comparative aspect with an analogous preparation of imported production and the results obtained from healthy animals. Clinical, haematological, and biochemical methods of investigation were employed. The findings obtained suggest a high therapeutic effect of the created preparation. Its application allowed reducing the duration of the treatment period by 5-7 days compared to the imported preparation and restoring the positive dynamics of average daily gain as early as on the 5th day after the start of treatment. Haematological studies indicate stimulation of the immune system in animals that was manifested by a 14% increase in the count of lymphocytes and a 37% increase in the proteins of the γ-globulin fraction compared to healthy animals. These indices suggest an increase in the activity of the humoral part of the immune system in animals after treatment with the preparation. Another positive therapeutic effect of the preparation was observed in the protective effect on the liver of diseased animals. Despite the present effect of both preparations, the decrease in the activity of markers characterising hepatocyte destruction was higher with the Kazakh preparation. Thus, the created preparation is characterised by a higher therapeutic effect in comparison with the imported preparation and allow recommending it for treatment and prevention of diarrhoea in young animals

Ribosomal protein L17 functions as an antimicrobial protein in amphioxus

Antimicrobial peptides (AMPs), characterized by their cationic nature and amphiphilic properties, play a pivotal role in inhibiting the biological activity of microbes. Currently, only a fraction of the antimicrobial potential within the ribosomal protein family has been explored, despite its extensive membership and resemblance to AMPs. Herein we demonstrated that amphioxus RPL17 (BjRPL17) exhibited not only upregulated expression upon bacterial stimulation but also possessed bactericidal capabilities against both Gram-negative and -positive bacteria through combined action mechanisms including interaction with cell surface molecules LPS, LTA, and PGN, disruption of cell membrane integrity, promotion of membrane depolarization, and induction of intracellular ROS production. Furthermore, a peptide derived from residues 127–141 of BjRPL17 (termed BjRPL17-1) showed antibacterial activity against Staphylococcus aureus and its methicillin-resistant strain via the same mechanism observed for the full-length protein. Additionally, the rpl17 gene was highly conserved in Metazoa, hinting it may play a universal role in the antibacterial defense system in different animals. Importantly, neither BjRPL17 nor peptide BjRPL17-1 exhibited toxicity towards mammalian cells thereby offering prospects for designing novel AMP agents based on these findings. Collectively, our results establish RPL17 as a novel member of AMPs with remarkable evolutionary conservation.

Effect of the organoselenium compound 974zh on the TLR2 and TLR4 gene expression in blood and spleen cells of experimental animals when co-administered with Yersinia pestis EV

One of the important directions for increasing the immunogenic properties of vaccine strains against highly dangerous infections is the search for adjuvants that not only stimulate the immunological effectiveness of vaccination, but can also provide a metabolic correction of the vaccination process. Organoselenium compounds have immunotropic properties and an antioxidant effect, and therefore, the study of the effect of the organoselenium compound 2,6-dipyridinium-9-selenabicyclo[3.3.1]nonane dibromide (974zh) on the activity of the TLR2 and TLR4 gene expression by macroorganism cells of experimental animals immunized with Yersinia pestis EV NIIEG vaccine strain, is a current area of research.The aim of the work. To assess the TLR2 and TLR4 gene expression by cells of the immune phagocyte system of experimental animals immunized with the Y. pestis EV vaccine strain against the background of immunomodulation with the organoselenium compound 974zh.Materials and methods. The study was carried out on 125 certified outbred white mice. Biological material (blood, spleen) was disinfected, and the spleen was homogenized. RNA isolation and reverse transcription were performed using commercial reagent kits. The expression level of the TLR2 and TLR4 genes was determined using real-time polymerase chain reaction with specific primers.Results. When assessing innate immunity using the example of blood and spleen cells of animal models, features of the TLR2 and TLR4 gene expression were revealed in response to the introduction of the Y. pestis EV vaccine strain against the background of immunomodulation with the 974zh. It was found that 974zh induces a statistically significant increase in TLR2 gene expression when co-administered with Y. pestis EV at a dose of both 104 CFU and 103 CFU.Conclusion. Y. pestis EV against the background of immunomodulation with 974zh, stimulates the expression of the TLR2 and TLR4 genes, which may indicate an increase in the immunogenic properties of the Y. pestis EV vaccine strain under the influence of this preparation.

Citrinin Provoke DNA Damage and Cell-Cycle Arrest Related to Chk2 and FANCD2 Checkpoint Proteins in Hepatocellular and Adenocarcinoma Cell Lines.

Citrinin (CIT), a polyketide mycotoxin produced by Penicillium, Aspergillus, and Monascus species, is a contaminant that has been found in various food commodities and was also detected in house dust. Several studies showed that CIT can impair the kidney, liver, heart, immune, and reproductive systems in animals by mechanisms so far not completely elucidated. In this study, we investigated the CIT mode of action on two human tumor cell lines, HepG2 (hepatocellular carcinoma) and A549 (lung adenocarcinoma). Cytotoxic concentrations were determined using an MTT proliferation assay. The genotoxic effect of sub-IC50 concentrations was investigated using the alkaline comet assay and the impact on the cell cycle using flow cytometry. Additionally, the CIT effect on the total amount and phosphorylation of two cell-cycle-checkpoint proteins, the serine/threonine kinase Chk2 and Fanconi anemia (FA) group D2 (FANCD2), was determined by the cell-based ELISA. The data were analyzed using GraphPad Prism statistical software. The CIT IC50 for HepG2 was 107.3 µM, and for A549, it was >250 µM. The results showed that sensitivity to CIT is cell-type dependent and that CIT in sub-IC50 and near IC50 induces significant DNA damage and cell-cycle arrest in the G2/M phase, which is related to the increase in total and phosphorylated Chk2 and FANCD2 checkpoint proteins in HepG2 and A549 cells.

The Integrative Life history of Maternal Effects.

Context-dependent allocation of resources drives trade-offs among fitness-related traits and other phenotypes to which those traits are linked. In addition, the amount and type of acquired resources can also affect the phenotypes of other organisms through indirect genetic effects, as exemplified by the maternal provisioning of offspring. Despite a large literature on maternal effects, we lack a comprehensive understanding of the extent to which mothers might affect the phenotypes of their offspring, as well as the various mechanisms by which they do so, particularly with regard to many functional traits that are key determinants of survival and reproduction. Our goals in this paper are to review the various approaches to measuring and understanding maternal effects, and to highlight some promising avenues for integration of maternal effects with some other key areas of evolutionary ecology. We focus especially on nutritional geometry; maternal age; and traits proximate to fitness such as whole-organism performance. Finally, we discuss the logistic and practical limits of quantifying these effects in many animal systems, and emphasize the value of integrative approaches in understanding the mechanisms underlying maternal influence on offspring phenotypes.

Through an animal's eye: the implications of diverse sensory systems in scientific experimentation.

'Accounting for the sensory abilities of animals is critical in experimental design.' No researcher would disagree with this statement, yet it is often the case that we inadvertently fall for anthropocentric biases and use ourselves as the reference point. This paper discusses the risks of adopting an anthropocentric view when working with non-human animals, and the unintended consequences this has on our experimental designs and results. To this aim, we provide general examples of anthropocentric bias from different fields of animal research, with a particular focus on animal cognition and behaviour, and lay out the potential consequences of adopting a human-based perspective. Knowledge of the sensory abilities, both in terms of similarities to humans and peculiarities of the investigated species, is crucial to ensure solid conclusions. A more careful consideration of the diverse sensory systems of animals would improve many scientific fields and enhance animal welfare in the laboratory.

Emamectin benzoate exposure induced carp kidney injury by triggering mitochondrial oxidative stress to accelerate ferroptosis and autophagy

Emamectin benzoate (EMB), commonly used as an insecticide in fishery production, inevitably leaves residual chemicals in aquatic environments. High-level EMB exposure can cause severe damage to multiple systems of marine animals, potentially through mechanisms involving severe mitochondrial damage and oxidative stress. However, it is not clear yet how EMB exposure at a certain level can cause damage to fish kidney tissue. In this study, we exposed carps to an aquatic environment containing 2.4 μg/L of EMB and cultured carp kidney cells in vitro, established a cell model exposed to EMB. Our findings revealed that EMB exposure resulted in severe kidney tissue damage in carp and compromised the viability of grass carp kidney cells (CIK cells). By RNA-seq analysis, EMB exposure led to significant differences in mitochondrial homeostasis, response to ROS, ferroptosis, and autophagy signals in carp kidney tissue. Mechanistically, EMB exposure induced mitochondrial oxidative stress by promoting the generation of mitochondrial superoxide and reducing the activity of antioxidant enzymes. Additionally, EMB exposure triggered loss of mitochondrial membrane potential, an imbalance in mitochondrial fusion/division homeostasis, and dysfunction in oxidative phosphorylation, ultimately impairing ATP synthesis. Notably, EMB exposure also accelerated excessive autophagy and ferroptosis of cells by contributing to the formation of lipid peroxides and autophagosomes, and the deposition of Fe2+. However, N-acetyl-L-cysteine (NAC) treatment alleviated the damage and death of CIK cells by inhibiting oxidative stress. Overall, our study demonstrated that EMB exposure induced mitochondrial oxidative stress, impaired mitochondrial homeostasis, and function, promoted autophagy and ferroptosis of kidney cells, and ultimately led to kidney tissue damage in carp. Our research enhanced the toxicological understanding on EMB exposure and provides a model reference for comparative medicine.

Investigation through Animal-Computer Interaction: A Proof-of-Concept Study for the Behavioural Experimentation of Colour Vision in Zoo-Housed Primates.

Zoos are an important repository of animals, which have a wide range of visual systems, providing excellent opportunities to investigate many comparative questions in sensory ecology. However, behavioural testing must be carried out in an animal welfare-friendly manner, which is practical for zoo staff. Here, we present a proof-of-concept study to facilitate behavioural research on the sensory ecology of captive primates. A system consisting of a tablet computer and an automated feeder connected wirelessly was developed and presented to captive primate species to evaluate interactions with and without previous training. A colour stimulus, analogous to the Ishihara test, was used to check the level of interaction with the device, supporting future studies on sensory ecology with zoo animals. Animals were able to use the system successfully and displayed signs of learning to discriminate between the visual stimuli presented. We identified no risk for small primates in their interactions with the experimental setup without the presence of keepers. The use of electronic devices should be approached with caution to prevent accidents, as a standard practice for environmental enrichment for larger animals (e.g., spider monkeys). In the long term, the system developed here will allow us to address complex comparative questions about the functions of different visual systems in captive animals (i.e., dichromatic, trichromatic, etc.).

Asymptomatic herpes simplex virus brain infection elicits cellular senescence phenotypes in the central nervous system of mice suffering multiple sclerosis-like disease

Experimental autoimmune encephalomyelitis (EAE) is a demyelinating disease affecting the central nervous system (CNS) in animals that parallels several clinical and molecular traits of multiple sclerosis in humans. Herpes simplex virus type 1 (HSV-1) infection mainly causes cold sores and eye diseases, yet eventually, it can also reach the CNS, leading to acute encephalitis. Notably, a significant proportion of healthy individuals are likely to have asymptomatic HSV-1 brain infection with chronic brain inflammation due to persistent latent infection in neurons. Because cellular senescence is suggested as a potential factor contributing to the development of various neurodegenerative disorders, including multiple sclerosis, and viral infections may induce a premature senescence state in the CNS, potentially increasing susceptibility to such disorders, here we examine the presence of senescence-related markers in the brains and spinal cords of mice with asymptomatic HSV-1 brain infection, EAE, and both conditions. Across all scenarios, we find a significant increases of senescence biomarkers in the CNS with some differences depending on the analyzed group. Notably, some senescence biomarkers are exclusively observed in mice with the combined conditions. These results indicate that asymptomatic HSV-1 brain infection and EAE associate with a significant expression of senescence biomarkers in the CNS.

Chlamydomonas

Tulin et al. introduce Chlamydomonas, a unicellular green alga commonly used as a microbial reference system for plants and animals.

Current status and challenges in disease surveillance and epidemiological investigation systems for companion animals in South Korea

Current status and challenges in disease surveillance and epidemiological investigation systems for companion animals in South Korea