1,720,968 research outputs found
Effect of media with different glycerol concentrations on sheep red blood cells’ viability in vitro
No full textThe use of high doses of glycerol as a livestock feed supplement is followed by a rapid increase in plasma concentrations and consequently in plasma osmolality. Moreover, glycerol is a highly diffusible molecule that can readily permeate the red blood cell (RBC) membrane following a concentration gradient. A rise in glycerol plasma concentrations can thus alter RBC homeostasis. The present study aimed at investigating both glycerol osmotic effects on sheep RBCs and their oxidative response under in vitro conditions. Sheep blood samples were suspended in media supplemented with increasing glycerol concentrations (0, 25, 50, 100, 150, 200, 250, 300, 350, 400 mg/dL), which reflected those found in vivo in previous studies, and incubated at 37 °C for 4h. Thereafter, osmolality and hemolysis were determined in spent media, while cell extracts were used to assay intracellular concentration of glycerol, ATP, Ca2+ ions, oxidative stress markers and reactive oxygen species (ROS).The study confirmed that glycerol intracellular concentrations are directly related with its concentration in the incubation media, as well as hemolysis (p < 0.001) which increased significantly at glycerol concentrations higher form 200 mg/dL. ROS intracellular level increased at all glycerol concentration tested (p < 0.01) and total thiols decreased at the highest concentrations. However, RBCs proved to be able to cope by activating their antioxidant defense system. Superoxide dismutase activity indeed increased at the highest glycerol concentrations (p < 0.001), while total antioxidant capacity and malonyldialdehyde, a typical product of lipid peroxidation by ROS, did not show significant changes. Moreover, no alterations in intracellular Ca2+ ions and ATP concentrations were found. In conclusion, glycerol‐induced hemolysis can be related to the induced osmotic stress. In sheep, nutritional treatments should be designed to avoid reaching glycerol circulating concentrations higher than 200 mg/dL
An Overview on Assay Methods to Quantify ROS and Enzymatic Antioxidants in Erythrocytes and Spermatozoa of Small Domestic Ruminants
Full text linkThe present review aims to provide an overview of the assay methods for the quantification of ROS and principal enzymatic antioxidants as biomarkers of oxidative stress in erythrocytes and spermatozoa of small domestic ruminants. A complete literature search was carried out in PubMed, Scopus and the World Wide Web using relevant keywords and focusing on the last five years (2018–2023). Among spectrophotometry, fluorometry and chemiluminescence, the most widely used method for ROS assay is fluorometry, probably because it allows to simultaneously assay several ROS, using different probes, with greater economic advantages. Regarding intracellular antioxidant enzymes, recent literature reports only spectrophotometric methods, many of which use commercial kits. The use of a less sensitive but cheapest method is suitable because both erythrocytes and spermatozoa samples are highly concentrated in domestic ruminant species. All methods considered in this review have been found to be appropriate; in general, the differences are related to their costs and sensitivity. Quantification of ROS and enzymatic antioxidant activity in erythrocytes and spermatozoa may find application in the study of the welfare and health status of small domestic ruminants for monitoring livestock production
Can Fecal T3 Metabolite Level Fluctuations in European Roe Deer (Capreolus capreolus) Give Insights on Body Condition and Thermal Stress?
No full textMammals can use a variety of physiological mechanisms to adapt to changes in their environment. Thyroid hormones (THs) are key modulators of growth and mediators of environmental conditions by regulating developmental processes and metabolism in animals. In recent years, advancements in non-invasive sampling have allowed monitoring of the fluctuations of THs and their metabolites in wild mammals. Triiodothyronine (T3) represents the major metabolite of THs excreted in feces so that it can be monitored in fecal samples. In this study, fecal samples collected during the hunting season from legally culled European roe deer (Capreolus capreolus; n = 160) were assayed to investigate the potential fluctuations of fecal TH metabolites (FTMs) in response to environmental (e.g., the temperature, local densities) and individual (e.g., sex, age, body, and nutritional conditions) variables. For this aim, we validated a TH enzyme immunoassay in the feces of roe deer. Our results show that FTMs can be successfully measured with satisfactory accuracy and precision. Extraction recovery (70%–120%), intra- and inter-day repeatability (<15%), linearity dilutions (80%–120%), and parallelism (<20%) were consistent with international guidelines. Environmental temperature (p < 0.001) showed a strong inverse correlation with FTM levels. THs can thus represent a reliable indicator in studying animals’ adaptative responses to environmental temperature changes, providing perspectives for the study of the impact of climate change on ungulates and mammals. Further analyses, comparing samples collected all year round, are needed to investigate the correlations of TH values versus the other investigated variables
Effect of PUFAs-ω3 and ω6 on oxidative stress of sheep erythrocytes
No full textBackground: In recent years, the use of long-chain polyunsaturated fatty acids (PUFA) ω3 and ω6, as food supplements in livestock has increased due to their beneficial properties related to their antioxidant activity. It has been demonstrated however that a high intake of these substances has prooxidant and cell-damaging effects, especially if their circulating concentrations are unbalanced. Starting from these premises, and taking advantage of previous findings, the present study aimed at defining the optimal circulating concentrations and PUFAs ω3/ω6 ratio, to ensure the antioxidant/oxidant balance in sheep RBCs. Results: All tested concentrations (25–300 μg/mL in PBS) of PUFAs-ω3 after 4 h of treatment on sheep RBCs, showed antioxidant properties with a significant decrease in reactive oxygen species (ROS) versus the control group (CTRL) (p < 0.05). Furthermore, ω6 showed an antioxidant effect at low concentrations (25–200 g/mL) but a pro-oxidant effect at the highest concentrations (250 and 300 μg/mL) with a significant increase in ROS production (123.6 ± 2.1 and 131.4 ± 6.5% sloope RFU of CTRL respectively p < 0,001), malondialdehyde (MDA) (p < 0.01), and haemolysis (p < 0.01) versus CTRL group (1.1 ± 0.1%), and, also with a decrease of Trolox equivalent antioxidant capacity (TEAC) (p < 0,05). The ratio ω3/ω6 of 1:10 (25/250 μg/mL) and 1:4 (25/100 μg/mL) showed an intracellular ROS level like the CTRL group whereas, the ratio 1:2 (100/200 μg/mL) resulted in a significant decrease in ROS production (62.71 ± 2.31% slope RFU of CTRL, p < 0.001) and MDA (p < 0.001), with an increase in TEAC (p < 0.05), and a decrease haemolysis versus the control group (p < 0,01). Conclusions: Our results showed that a beneficial effect on the oxidative state of sheep RBCs was obtained with in vitro administration of low concentrations of ω6 and with all tested concentrations of ω3. The addition of ω6 at high concentrations leads to an imbalance in the PUFA ω3/ω6 ratio, compromising the oxidative state and viability of the RBCs. The maximum antioxidative effect was found at ω3/ω6 ratio 1:2)
Fecal thyroid hormone metabolites in wild ungulates: a mini-review
No full textThis review aims to analyse the fluctuations of fecal thyroid hormone metabolites (FTMs) related to environmental and individual variables in different species of wild ungulates and provide a collection of assay methods. The great advantage of fecal sampling is being completely non-invasive. A systemic search was conducted from 2019 to 2024, using data sources PubMed, Scopus, Web of Science, and the World Wide Web, and ten studies were found on this topic. Three studies used the radioimmunoassay method for FTMs analysis, while the others used a less expensive enzyme-linked immunosorbent assay. Most of these papers validated the method for the species-specific matrix. Related to the studied variables, some authors analysed FTM fluctuations only concerning individual variables, and others in response to both. Temperature and fecal cortisol metabolites (FCMs) were the most studied environmental and individual variables, respectively. Since FTMs are an integrative measure of plasma thyroid hormones, the information obtained from a non-invasive-assay method regarding wild ungulate physiology is becoming of great interest to the scientific community
The Role of Vulture (Accipitriformes) Cutaneous Microbiota in Infectious Disease Protection
No full textVultures (Accipitriformes), as obligate scavengers, are regularly exposed to a diverse array of pathogens present in decomposing carcasses. Nevertheless, they exhibit a remarkable ability to resist infections, suggesting a crucial role of skin microbiota in host defense. The microbial communities residing on necrophagic birds’ skin create a protective barrier through competitive interactions, antimicrobial compound production, and immunity priming. Additionally, vultures contribute to ecosystem balance by reducing the spread of infectious agents. However, they may also serve as vectors for antimicrobial resistance (AMR) due to their exposure to contaminated food sources. Understanding the dynamics of their microbiota can provide valuable insights into host–microbe interactions, wildlife conservation, and public health. This review examines the composition and functional significance of vulture cutaneous microbiota. Specifically, it explores the role of necrophagic birds’ skin microbiota in pathogen exclusion, immune system modulation, and environmental adaptation, with the aim of suggesting further research routes, besides clarifying the ecological implications of such birds
Non-invasive Assay for Measurement of Fecal Triiodothyronine (T3) Metabolite Levels in European Mouflon (Ovis aries musimon)
Full text linkThyroid hormones (THs) are important indicators of metabolism and animal health. Traditionally, they have been determined from blood or urine samples. However, as their collection may be stressful and requires ethical approval, alternative non-invasive matrices are preferred when dealing with wild animals. Triiodothyronine (T3) is the active form of THs in blood and the major metabolite excreted in feces. This creates the ideal conditions for its assay in fecal samples. Fecal sampling eliminates the stress of the animals and the need to physically capture them. However, in wild species it is rare to find species-specific kits for the hormone assay. So, the objective of this work was to validate a method for the quantification of T3 metabolite (FTM) levels in feces of European mouflon by using an economic and easily available ELISA kit designed to quantify T3 in human plasma. Analytical and biological validations were performed in feces collected from 10 mouflons (5 ewes and 5 rams). An efficient liquid-extraction method was optimized. Precision, dilution linearity, parallelism, recovery and stability of T3 in fecal samples were calculated. Obtained data were considered acceptable according to international guidelines. The reliability of the results was verified comparing human plasma and mouflon fecal samples fortified with the same T3 standard solutions. The biological validation showed higher FTM levels in March compared to June, and no differences between mouflon ewes and rams. The validation of the present method provides a non-invasive and affordable tool for the quantification of FTM in European mouflon
Measurement of fecal T3 metabolite levels in sheep: Analytical and biological validation of the method
No full textIntroduction: Biological sample collection from wild and farms animals is often associated with difficulties related to the handling and restraint procedures, and most of the time it could induce stress, altering the welfare and physiological homeostasis. The analysis of fecal T3 metabolites (FTMs) allows to test samples collected in a non-invasive manner, providing several information about the animal's physiological conditions and the effects related to environmental and nutritional variations. This procedure has found wide application in wild species, but less in domestic ones. Methods: The aim of this work was to validate the use of an immuno-enzymatic competitive ELISA kit, designed for T3 quantification in human blood serum samples, for the assessment of FTMs in the sheep. For the analytical validation, precision, recovery and parallelism were evaluated; for biological validation the variations of FTMs in relation to age, sex and the physiological status of the animal were determined. Results: After a verification of the precision (RSD % < 15%), mean recovery (75%) and parallelism (CV% < 10%), the kit was used to measure FTMs in cyclic, pregnant, and early lactating ewes as well as in rams and ewe lambs. The results showed that FTMs concentrations in pregnant ewes were significantly lower (p < 0.05) than in cyclic and early lactation ones. Furthermore, there were no significant differences in FTMs levels between ewes and rams, while in lambs FTMs levels were higher than in adults (p < 0.001). Conclusion: In conclusion the present study demonstrates that FTMs can be reliably and accurately determined in sheep feces, using an ELISA kit formulated for human serum T3 assay. The application of this method in the livestock sector could allow to improve our knowledge about the response of animals to different physiological and environmental conditions, and thus assess their welfare
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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