The Role of Antioxidants in Animal Health: Fighting Oxidative Stress in Livestock
Sweta Rani*, Amrita Behera, Ajeet Kumar
Sweta Rani: M.V.Sc Scholar, Department of Veterinary Biochemistry, Bihar Veterinary College, BASU, Patna; email id: singhsweta021@gmail.com
Amrita Behera: Assistant Professor cum Junior Scientist, Department of Veterinary Biochemistry, Bihar Veterinary College, BASU, Patna; email id: amrita23b@gmail.com
Ajeet Kumar: Associate Professor cum Senior Scientist, Department of Veterinary Biochemistry, Bihar Veterinary College, BASU, Patna; email id: ajeet18@gmail.com
Introduction
Livestock production is fundamental to global food security, delivering essential proteins and nutrients via meat, milk, and eggs. However, oxidative stress frequently poses a significant challenge in animal husbandry, often compromising the health and productivity of these animals. Oxidative stress arises from a disruption in the balance between free radicals (reactive oxygen species) and the antioxidant defense system, contributing to cellular damage and hindered physiological processes. This condition not only compromises the overall health of livestock but further modifies their growth, reproduction, and immune response, leading to an effect on productivity. To mitigate these detrimental impacts, the strategic use of antioxidants in livestock management has gained prominence. Antioxidants, both endogenous and exogenous, play a significant role in balancing out free radicals, safeguarding cells from damage and supporting overall animal well-being.
Though the exploration of oxidative stress in livestock is an emerging area of research, it is swiftly advancing as we acquire more insight into how oxidants and antioxidants drive both normal and pathological conditions. Reactive species (RS), comprising free radicals, were historically considered entirely detrimental owing to their highly reactive nature. Nevertheless, it has become apparent that they also contribute beneficially to normal physiological functions, as exemplified by immune defense mechanisms, cellular communication, and metabolic pathway regulation. This twofold nature underscores the importance of antioxidants— not solely in tackling oxidative damage along with maintaining the advantageous roles of RS in biological frameworks (Halliwell & Gutteridge, 2007).
The expanding field of research on oxidative stress in livestock science highlights the necessity to develop optimal management approaches to manage its consequences. Aspects as exemplified by poor dietary intake, elevated metabolic rates, environmental contaminants, and infections can amplify oxidative stress levels in livestock, bringing about diminished productivity and increased disease susceptibility. Dietary supplementation coupled with antioxidants has surfaced as an effective framework for modulating oxidative stress, thus augmenting livestock health, growth metrics, reproductive effectiveness, and immune system functionality.
Unraveling Oxidative Stress:
The perception of oxidative stress has progressed substantially post-1970s, broadening beyond a narrow emphasis concerning the negative effects of free radicals to acknowledging their twofold aspects in both typical physiological roles and pathological scenarios. Highly reactive molecules, known as free radicals or reactive species (RS), are unstable and readily engage in chemical reactions signified by unpaired electrons. These entities, incorporating reactive oxygen species (ROS) as exemplified by superoxide anions, hydrogen peroxide, along with hydroxyl radicals, are inherent collateral products derived from oxygen-dependent biochemical processes. While they were initially perceived solely as damaging agents, further down the line research illustrated their significant roles in immune system defense, intercellular signaling, and metabolic pathway oversight (Costantini, 2019). Conversely, a surplus buildup of ROS can overpower the body’s antioxidant defenses, effectuating oxidative stress—a situation identified as an discrepancy in the context of pro-oxidants and antioxidants, bringing about possible damage to cellular structures (Lykkesfeldt & Svendsen, 2007).
Oxidative stress is fundamentally equivalent to interruption pertaining to redox signaling and regulatory mechanisms (Jones, 2006). It manifests under circumstances where exists certain overabundance concerning ROS owing to amplified concentrations involving intrinsic or extrinsic compounds facing autoxidation otherwise additional mechanisms which can yield ROS, accompanied by a compromised ability to nullify such reactive species else rectify the effects they create. The following misalignment may result in oxidative damage affecting major biomolecules as exemplified by lipids, proteins, and DNA, eventually distressing usual metabolic processes and physiological mechanisms along with leading to a reduction in cellular activity, cell death, or necrosis. Dwelling in an oxygen-saturated environment brings about inherent threats, as reflected in the “Oxygen Paradox,” at which oxygen is fundamental for existence but also a source of danger due to the generation of ROS (Davies, 2000). To persist in such an adverse situation, organisms have implemented a range of antioxidant defenses, such as regenerable enzymes along with substances that alleviate oxidative damage. Regardless of these advanced defenses, oxidative damage remains prevalent, together with considerations including nutrition, dietary supplements, essential minerals, and exercise could modulate the scale concerning this impairment.
Different Manifestations of Oxidative Stress:
Oxidative stress can be categorized based on its origin and impact:
- Acute Oxidative Stress: This form develops rapidly and is frequently linked to a particular trigger namely pathogenic infection, high-intensity exercise, or adverse environmental conditions such as heat waves or cold spells. Acute oxidative stress can cause temporary yet substantial cellular damage, impacting the performance and health of animals.
- Chronic Oxidative Stress: This manifests over an extended period .Moreover, it is frequently associated with long-term conditions including inadequate nutrition, prolonged exposure to environmental stressors, or ongoing infections. Persistent oxidative stress may cause enduring health problems like impaired growth, reproductive challenges, and a weakened immune system.
- Localized Oxidative Stress: Such a kind of oxidative stress is constrained to specified tissues or organs. For instance, respiratory infections can lead to oxidative stress in the lungs, whereas toxin exposure can induce oxidative stress in the liver.
- Systemic Oxidative Stress: Such effects influence the entire body and are commonly encountered in severe conditions or significant stress, causing widespread cellular damage.
Role of Oxidative Stress in Livestock Health:
Livestock health is greatly impacted by oxidative stress, which affects diverse physiological processes:-
- Cellular disruption: When levels of reactive oxygen species are too high, they can trigger lipid peroxidation, protein oxidation, and DNA damage, which subsequently leads to cellular dysfunction and cell death. As a result, this may lead to tissue damage, reduced organ function, and lower productivity in livestock.
- Inflammation: Livestock can experience exacerbated conditions such as mastitis, arthritis, and respiratory diseases due to oxidative stress triggering inflammatory responses.
- Immune system suppression: Livestock can experience a weakened immune system due to prolonged oxidative stress, making them more susceptible to infections and less capable of recovering from diseases.
- Reproductive complications: Livestock have been linked to reproductive failures due to oxidative stress, which can result in reduced fertility, poor embryo development, and a higher incidence of miscarriages.
Biochemical Tests for Assessing Oxidative Stress:
Various biochemical tests are employed to evaluate oxidative stress in livestock. These tests assist in diagnosing conditions related to oxidative stress and in monitoring the efficacy of antioxidant treatments.
- Measurement of Malondialdehyde (MDA): As a by-product of lipid peroxidation, MDA is frequently employed as a biomarker for oxidative stress. Enhanced levels related to MDA within blood or tissues suggest higher lipid damage due to oxidative stress
- Antioxidant Enzyme Activity: Antioxidant enzymes, including superoxide dismutase (SOD), catalase, and glutathione peroxidase (GPx), are measured to assess the antioxidant capacity of the animal. Reduced enzyme activity indicates weakened antioxidant defenses.
- Total Antioxidant Capacity (TAC): TAC determines the animal’s overall effectiveness in neutralizing ROS. It gives an overview of the overall antioxidant status, encompassing both enzymatic and non-enzymatic antioxidants.
- Glutathione Levels: Intracellularly, glutathione is a major antioxidant. An important marker of oxidative stress is the ratio between reduced glutathione (GSH) and oxidized glutathione (GSSG). An altered GSH/GSSG ratio, with lower GSH, suggests elevated oxidative stress
- Carbonylation of proteins: The assay determines the level of carbonylated proteins, which increase as a result of oxidative damage. An increase in protein carbonyl content points to protein oxidation and heightened oxidative stress.
Oxidative Stress Management Protocol for Livestock:
Livestock management of oxidative stress involves a combination of dietary interventions, environmental management, and health monitoring. The following protocol outlines strategies to mitigate oxidative stress:
Management of Nutritional Strategies:
- Antioxidant Enrichment: Livestock ought to be given within dietary guidelines enriched with both endogenous along with exogenous antioxidants. Indispensable antioxidants, encompassing vitamin E, vitamin C, selenium, together with zinc, need to be incorporated. Furthermore, livestock may derive benefits from feed additives featuring plant-sourced flavonoids, carotenoids, and polyphenols, consequently enhance their antioxidant defenses.
- Nutrient-Balanced Diet: Livestock need to be equipped with a well-balanced diet that addresses their dietary requirements, as inadequacies in essential nutrients has the potential to exacerbate oxidative stress.
- Supplementary Support: In scenarios of advanced oxidative stress, it is suggested to take under advisement incorporation of antioxidants to illustrate vitamin E along with selenium to elevate the antioxidant capacity of the animals. Research findings suggest that both natural (RRR α-tocopherol acetate) and synthetic (all-rac α-tocopherol acetate) forms of vitamin E supplementation may have a beneficial effect on reproductive efficiency in beef cows (Horn et al., 2010).
Sustainability Management:
- Mitigating Stress: Reduce environmental stressors by providing proper ventilation, temperature control, and maintaining clean housing conditions. Additionally, minimizing overcrowding and managing handling practices can help lessen the chances of oxidative stress.
- Gentle Handling: Stress-inducing environments, as illustrated by habitual transportation or challenging weather patterns, need to be circumvented to mitigate oxidative stress in livestock. Gentle handling practices might likewise significantly cut down on acute oxidative stress.
Evaluating health parameters:
- Routine Health Assessments: Livestock need to be periodically inspected to evaluate markers of oxidative stress, as demonstrated by restricted growth, reproductive complications, or higher incidence of infections. Early detection allows for prompt intervention to address these issues.
- Biochemical Evaluations: Livestock should undergo routine biochemical tests to assess oxidative stress levels, especially in high-stress environments or intensive production systems. Monitoring markers of oxidative damage and antioxidant enzyme activity provides valuable insights for making informed management decisions.
Implementation of Natural Antioxidants:
- Incorporation of Herbal Supplements: Livestock can benefit from a diet that integrates natural herbs and plant extracts with proven antioxidant properties, such as turmeric (containing curcumin), green tea (rich in catechins), and rosemary (which contains rosmarinic acid).
- Inclusion of Probiotics: Livestock should ideally be administered probiotics to facilitate gut health, since a healthy gut can assist in decreasing ROS production and optimize overall antioxidant status.
Immunization Strategies and Disease Oversight:
- Preventative Vaccine Administration: Livestock should be protected from prevalent diseases through the implementation of vaccination protocols, which helps minimize the risk of infections that can induce oxidative stress.
- Prompt Treatment: Livestock should receive timely intervention for infections and inflammatory conditions to prevent prolonged oxidative stress.
Conclusion
Maintaining and improving livestock health, productivity, and welfare relies heavily on the effectiveness of antioxidants in counteracting oxidative stress. When pro-oxidants and antioxidants are out of balance, oxidative stress can severely impact animal health, resulting in cellular damage, disrupted physiological functions, and reduced productivity. The strategic application of antioxidants, including Vitamin E and selenium, provides a crucial opportunity to alleviate oxidative stress and enhance livestock health and production. Current evidence points to the fact that elevating antioxidant supplementation beyond the recommended levels might provide beneficial outcomes; nevertheless, this potential requires a comprehensive examination along with extensive research to pinpoint the most effective dosages and the optimal conditions for the proper administration of these supplements.
With ongoing developments in the understanding of oxidative stress within veterinary medicine, incorporating cutting-edge “omics” technologies—such as genomics, proteomics, and metabolomics—into research offers a comprehensive framework, known as “oxi-animal omics,” for exploring and understanding the intricate interactions between antioxidants and animals. This integrated approach enables a thorough examination of the molecular and biochemical processes involved, providing a holistic perspective on how antioxidants influence animal health and stress responses. This comprehensive approach has the potential to shed light on the fundamental mechanisms involved, offering valuable insights into how antioxidants interact with biological systems. It could facilitate a deeper understanding of the underlying processes, leading to the development of more effective antioxidant therapies and targeted interventions to improve animal health and mitigate oxidative stress. Future research should concentrate on identifying and validating dependable biomarkers for oxidative stress, establishing standardized methodologies for assessment, and investigating comprehensive antioxidant strategies specifically designed to meet the diverse health needs of animals. Embracing a holistic, evidence-based approach to the integration of antioxidants into animal nutrition will enable us to substantially improve livestock health, boost productivity, and advance sustainable and ethical farming practices. This integrated strategy will facilitate more precise and effective interventions, ultimately supporting the long-term welfare and performance of livestock while promoting environmentally responsible farming methods.
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