Abhishek Pathak1*and Simran Shekhawat2
1Department of Veterinary Pharmacology & Toxicology, C.V.A.Sc, G.B. Pant University of Agriculture & Technology, Pantnagar-263145, Uttarakhand, India.
2Apollo College of Veterinary Medicine, Jaipur-302031, Rajasthan, India
*Corresponding author email: firstname.lastname@example.org
Nickel toxicity in animals is a pressing concern with significant implications for both livestock health and food safety. Nickel exposure in livestock can occur through contaminated feed, water, soil, and air, necessitating proactive monitoring to reduce the risk of toxicity. The clinical signs of nickel toxicity in animals can be nonspecific, demanding careful veterinary evaluation and consideration of environmental exposure history for accurate diagnosis. Timely detection and intervention are crucial to prevent further health complications and mitigate the impact of nickel toxicity on livestock.The transfer of nickel from animals to humans through the consumption of animal products raises food safety concerns. Monitoring nickel levels in animal products and conducting risk assessments are essential to ensure compliance with regulatory limits and safeguard consumers. Nickel allergies and sensitization further underscore the need for attention to food safety.Future research directions are proposed to advance our understanding of nickel-induced toxicity. Investigating the mechanisms of nickel-induced toxicity, identifying early detection biomarkers, and assessing long-term effects are vital areas of exploration. Species-specific responses, interactions with other elements, and impacts on gut microbiota also warrant investigation to inform targeted intervention strategies.Overall, nickel toxicity in animals calls for a collaborative approach involving farmers, veterinarians, researchers, regulatory bodies, and consumers. Understanding the sources of exposure, potential health impacts, and implementing preventive measures are essential to safeguard both animal well-being and human health. Continued research, education, and collaboration are keys to developing evidence-based approaches for the prevention and management of nickel toxicity, promoting sustainable agriculture and ensuring food safety. Protecting livestock from nickel toxicity not only preserves their health and welfare but also enhances the safety and quality of animal-derived products for human consumption.
Nickel, a naturally occurring transition metal, is widely distributed in the environment and is commonly used in various industrial processes. While essential trace amounts of nickel play a role in enzymatic reactions and metabolic processes, elevated levels of nickel exposure can lead to toxicity in animals, including livestock. Nickel toxicity has emerged as a growing concern due to its potential adverse effects on animal health and the implications it holds for the livestock industry and food safety.Animals, including livestock, can be exposed to nickel through multiple routes, including contaminated feed, water, air, and soil. Agricultural environments may contain elevated nickel concentrations due to industrial activities, mining operations, and the use of nickel-containing pesticides and fertilizers. As livestock graze on pastures and consume feed, they can accumulate nickel in their bodies, leading to a range of health issues.
The impact of nickel toxicity on livestock health is multifaceted and can manifest in various ways. Nickel’s toxic effects may affect different organ systems, leading to respiratory problems, gastrointestinal disturbances, impaired growth, and reproductive disorders in livestock species. The severity of nickel toxicity depends on factors such as the species, age, and duration of exposure, as well as individual variations in nickel metabolism.Diagnosing nickel toxicity in animals can be challenging, as clinical signs may resemble those of other diseases. Veterinarians often face difficulties in accurately identifying nickel poisoning, necessitating thorough environmental exposure history and diagnostic investigations to confirm the diagnosis.To safeguard livestock health and human well-being, implementing preventive measures is essential. Monitoring nickel levels in feed and water, practicing responsible waste disposal, and employing soil management techniques are critical in mitigating nickel exposure risks.Moreover, the transfer of nickel from animals to humans through the consumption of animal products raises food safety concerns. Understanding the potential human health implications of nickel toxicity in livestock underscores the importance of addressing this issue proactively.
In light of these concerns, this review article aims to provide a comprehensive analysis of nickel toxicity in animals, with a specific focus on its impact on livestock health. The article will delve into the sources of nickel exposure, mechanisms of absorption and distribution in animals, the toxic effects on different livestock species, diagnostic challenges faced by veterinarians, preventive measures, and potential future research directions.By understanding the complexities of nickel toxicity in animals and its implications for livestock health and food safety, we can develop targeted strategies to safeguard animal well-being and ensure the production of safe and high-quality animal products for human consumption.
2. Sources of Nickel Exposure:
Sources of nickel exposure in animals can vary widely, encompassing both natural and anthropogenic origins. Nickel is a naturally occurring element present in the Earth’s crust, and its release into the environment can result from geological processes. However, human activities have significantly contributed to the dissemination of nickel in various environmental compartments, leading to potential exposure pathways for animals. Some of the primary sources of nickel exposure in animals include:
Contaminated Soil: Agricultural soils may contain elevated levels of nickel due to the deposition of industrial emissions, sewage sludge application, and the use of nickel-containing fertilizers. Livestock grazing on pastures with high nickel content can inadvertently consume the metal.
Contaminated Water: Water sources can become contaminated with nickel through industrial discharges, mining activities, and urban runoff. Livestock that drink water from such sources may ingest nickel, leading to potential health risks.
Feed Contamination: Nickel can enter the food chain through contamination of animal feed. Feed ingredients, particularly plant-based materials, can accumulate nickel from the surrounding environment, and animals consuming these feeds may be exposed to the metal.
Industrial Emissions: Nickel and its compounds are used in various industrial processes, such as metal plating, stainless steel production, and battery manufacturing. Industrial emissions release nickel particles and compounds into the atmosphere, which can subsequently settle onto pasturelands and crops, contaminating animal feed.
Waste and Landfills: Improper disposal of nickel-containing waste and electronic devices can contribute to environmental nickel pollution. If these waste materials are not adequately managed, they can leach nickel into soil and water, potentially reaching livestock habitats.
Mining Activities: Nickel mining operations can release substantial amounts of the metal into the surrounding environment. Dust and runoff from mining activities can lead to nickel contamination of nearby agricultural areas.
Nickel-Containing Pesticides and Fertilizers: Agricultural practices involving the use of nickel-containing pesticides and fertilizers can lead to the accumulation of nickel in soil and plants, which may subsequently be ingested by animals.
Urbanization: Urban areas often have elevated nickel levels due to industrial activities and vehicular emissions. Livestock residing in or near urban centers may be exposed to higher nickel concentrations.
Atmospheric Deposition: Nickel particles released into the atmosphere can undergo long-range transport and deposit in remote areas, including farmland and grazing lands, introducing nickel to animal environments.
3. Absorption and Distribution:
Absorption and distribution of nickel in animals are complex processes that determine the metal’s bioavailability and potential toxic effects. Understanding these mechanisms is crucial in assessing the risks of nickel toxicity and developing appropriate preventive measures. The absorption and distribution of nickel in animals involve several steps:
Absorption in the Gastrointestinal Tract:
Upon ingestion, nickel encounters the acidic environment of the gastrointestinal tract. Nickel can be absorbed through both passive diffusion and active transport mechanisms. In the stomach, low pH conditions can enhance nickel solubility, increasing its bioavailability for absorption in the small intestine.
Absorption in the Small Intestine:
The majority of nickel absorption occurs in the small intestine. Absorption efficiency can vary among animal species, with monogastric animals (e.g., pigs and poultry) generally exhibiting higher absorption rates compared to ruminants (e.g., cattle and sheep). Factors such as dietary composition, pH, and presence of other elements can influence nickel absorption in the intestine.
Circulation and Distribution in Blood:
Once absorbed, nickel enters the bloodstream, where it is bound to plasma proteins. Nickel can exist in various forms, including free ions, complexes, and protein-bound forms. Circulating nickel is distributed throughout the body, and the metal’s distribution can be influenced by factors such as blood flow, tissue permeability, and protein binding capacity.
Nickel has an affinity for certain tissues, and its accumulation in specific organs can lead to toxicity. Liver and kidneys are major target organs for nickel accumulation in animals. Additionally, nickel can accumulate in the lungs, spleen, brain, and reproductive organs.
Cellular Uptake and Intracellular Binding:
Within tissues, nickel can enter cells via various transport mechanisms. Nickel ions can bind to cellular structures, including proteins and enzymes, affecting cellular functions. Nickel can disrupt enzymatic activities and interfere with cellular processes, leading to oxidative stress and cellular damage.
The elimination of absorbed nickel occurs primarily through urine and feces. In ruminants, nickel can also be excreted through saliva during rumination. The rate of excretion varies depending on the animal species, age, and overall nickel exposure.
Factors Affecting Absorption and Distribution:
Several factors influence the absorption and distribution of nickel in animals:
Dietary Factors: The presence of other elements in the diet, such as calcium and iron, can compete with nickel for absorption and binding sites, affecting its bioavailability.
pH Levels: Gastric acidity and intestinal pH can influence the solubility and absorption of nickel.
Age and Species: Absorption efficiency and tissue distribution of nickel may vary among different animal species and developmental stages.
Nutritional Status: Nutritional deficiencies or imbalances can influence the body’s handling of nickel and its interaction with other nutrients.
4.Nickel Toxicity in Livestock:
Nickel toxicity in livestock is a significant concern that can affect various animal species, including cattle, poultry, swine, and sheep. The toxic effects of nickel can lead to a range of health issues, impacting the overall well-being and productivity of livestock. Understanding the specific health issues associated with nickel toxicity in different livestock species is crucial in developing targeted intervention strategies and preventive measures.
Cattle are particularly susceptible to nickel toxicity due to their grazing habits and potential exposure to nickel-contaminated pastures and feed. Chronic exposure to elevated levels of nickel in cattle can result in respiratory problems, including chronic bronchitis and pulmonary fibrosis. Nickel particles and compounds in the air can be inhaled by cattle during grazing, leading to damage in the respiratory system. This can manifest as coughing, wheezing, and labored breathing, affecting the overall respiratory health of the animals.
Poultry species, such as broilers and layers, can be exposed to nickel through contaminated feed and water. Excessive nickel levels in poultry diets have been associated with reduced feed intake and impaired growth. Poultry may also exhibit decreased egg production and changes in eggshell quality. The presence of nickel in poultry diets can interfere with nutrient absorption and metabolism, leading to suboptimal growth and performance.
Swine can be exposed to nickel through contaminated feed, water, and the environment. Nickel toxicity in swine has been associated with decreased feed efficiency and impaired reproductive performance. Elevated nickel levels in swine diets can lead to alterations in hematological parameters and liver function. Additionally, chronic exposure to nickel can result in liver and kidney damage in swine.
Sheep grazing on pastures with elevated nickel content are at risk of nickel toxicity. Chronic nickel exposure in sheep can lead to reduced weight gain, changes in blood parameters, and alterations in liver and kidney function. Additionally, nickel toxicity in sheep can impact reproductive health, leading to reduced fertility and impaired breeding performance.
The toxic effects of nickel on livestock can vary depending on the species, age, duration of exposure, and individual variations. It is essential for farmers and veterinarians to be aware of the potential health issues associated with nickel toxicity and take preventive measures to minimize nickel exposure in livestock. Implementing strategies to monitor and control nickel levels in feed, water, and soil can help safeguard animal health and welfare, ensuring optimal productivity and well-being in livestock populations. Further research is needed to better understand the mechanisms of nickel toxicity in different livestock species and develop effective strategies to mitigate the risks associated with nickel exposure in animals.
5. Diagnostic Challenges:
Diagnosing nickel toxicity in animals presents several challenges for veterinarians due to the nonspecific nature of clinical signs and the potential overlap with other diseases. Nickel toxicity shares similarities with various respiratory, gastrointestinal, and metabolic disorders, making it difficult to differentiate solely based on clinical observations. As a result, a comprehensive approach and careful consideration of the animal’s environmental exposure history are essential for accurate diagnosis.
Nonspecific Clinical Signs:
Clinical signs of nickel toxicity in animals are not unique to nickel exposure, and they can resemble those of many other diseases. Respiratory symptoms such as coughing and dyspnea are commonly observed in cases of nickel toxicity, but these signs can also be indicative of respiratory infections or environmental irritants. Gastrointestinal disturbances, including diarrhea and vomiting, are common manifestations of nickel toxicity, but these symptoms can be seen in various gastrointestinal disorders. This lack of specificity makes clinical diagnosis challenging.
Many diseases affecting animals, especially livestock, can manifest with similar clinical signs to those observed in nickel toxicity cases. For instance, respiratory problems in cattle may result from infectious agents, such as bovine respiratory syncytial virus (BRSV) or bovine viral diarrhea virus (BVDV). Similarly, gastrointestinal issues in poultry can be caused by infections, coccidiosis, or dietary imbalances. Distinguishing nickel toxicity from these overlapping diseases requires careful examination and a detailed history.
Environmental Exposure History:
Considering the environmental exposure history is crucial for accurate diagnosis. Veterinarians must inquire about the animal’s living conditions, the quality of feed and water sources, and the presence of any industrial or mining activities in the vicinity. Understanding the animal’s potential exposure to nickel-contaminated environments can help connect clinical signs to nickel toxicity and narrow down the list of differential diagnoses.
Laboratory and Diagnostic Investigations:
Laboratory tests and diagnostic investigations are instrumental in confirming nickel toxicity in animals. These may include blood tests to assess hematological parameters and serum biochemistry, which can reveal abnormalities associated with nickel toxicity. Additionally, lung function tests, such as bronchoalveolar lavage (BAL), can provide valuable information in cases of suspected respiratory nickel toxicity.
In certain cases, post-mortem examinations and tissue analysis may be required to confirm nickel toxicity definitively. Analyzing nickel levels in various tissues, especially in the liver and kidneys, can help identify nickel accumulation and corroborate the clinical diagnosis.
Diagnosing nickel toxicity in animals is challenging due to the nonspecific clinical signs and the potential overlap with other diseases. Veterinarians must consider the animal’s environmental exposure history, conduct thorough laboratory investigations, and, if necessary, perform tissue analysis to confirm nickel toxicity accurately. Ruling out other potential causes of clinical signs and implementing appropriate preventive measures are essential to safeguard animal health and welfare in environments at risk of nickel exposure.
6. Preventive Measures:
Preventing nickel toxicity in livestock requires a proactive approach that involves identifying potential sources of nickel exposure and implementing appropriate preventive measures. By adopting best practices, farmers and livestock owners can reduce the risk of nickel toxicity and safeguard the health and well-being of their animals.
Monitoring Nickel Levels in Feed and Water:
Regular monitoring of nickel levels in feed and water sources is crucial to ensure that animals are not exposed to excessive amounts of the metal. Nickel content in feed ingredients can vary depending on the source and cultivation practices. Implementing quality control measures for feed production and sourcing nickel-free feed ingredients can help minimize the risk of nickel toxicity.
Soil Management Techniques:
Contaminated soil can serve as a significant source of nickel exposure for grazing livestock. Implementing soil management techniques, such as phytoremediation and soil amendments, can help reduce nickel levels in pastures. Phytoremediation involves using specific plant species that have the ability to absorb and accumulate heavy metals like nickel from the soil, effectively cleaning up the environment. Soil amendments, such as liming, can also reduce nickel bioavailability and its uptake by plants.
Proper Waste Disposal:
Ensuring proper disposal of nickel-containing waste materials, such as industrial by-products and electronic waste, is essential in preventing environmental contamination. Implementing appropriate waste management practices, such as recycling or secure landfilling, can help minimize the release of nickel into the environment and reduce the risk of exposure to livestock.
Providing Clean Water Sources:
Access to clean and uncontaminated water is critical for livestock health. Regularly testing water sources for nickel and other contaminants can help identify potential risks and enable appropriate interventions if necessary. Providing access to clean and safe drinking water can reduce the likelihood of nickel exposure through water ingestion.
Using Nickel-Free Infrastructure and Equipment:
Farm infrastructure and equipment, such as water troughs, feeding bins, and housing materials, should be made from materials that do not contain nickel or other harmful heavy metals. Using nickel-free infrastructure can prevent potential leaching of nickel into the environment and protect livestock from unnecessary exposure.
Veterinary Monitoring and Health Management:
Regular veterinary monitoring of livestock health is essential for early detection of potential health issues, including nickel toxicity. Veterinarians can conduct clinical examinations and laboratory tests to assess animal health and screen for any signs of nickel toxicity. Timely intervention and appropriate treatment can prevent further health complications and mitigate the impact of nickel toxicity on livestock.
Education and Awareness:
Educating farmers, livestock owners, and farm workers about the risks of nickel toxicity and preventive measures is crucial. Raising awareness about the potential sources of nickel exposure and the importance of monitoring and management practices can empower stakeholders to take proactive measures in safeguarding animal health.
Preventive measures play a pivotal role in mitigating nickel toxicity in livestock. Monitoring nickel levels in feed and water, implementing soil management techniques, ensuring proper waste disposal, providing clean water sources, using nickel-free infrastructure, and promoting veterinary monitoring and health management are effective strategies to prevent nickel toxicity. By adopting these best practices, farmers and livestock owners can create a safer environment for their animals and promote their overall health and well-being.
7. Human Health Implications:
The human health implications of nickel toxicity in livestock are a crucial aspect that requires attention, particularly concerning food safety. The potential transfer of nickel from animals to humans through the consumption of animal products raises important concerns and underscores the significance of understanding nickel’s impact on livestock in the context of human health.
Nickel Transfer in the Food Chain:
Animals exposed to elevated levels of nickel can accumulate the metal in their tissues. The transfer of nickel from contaminated feed or forage to the animals’ tissues occurs during the feeding process. This process can lead to the bioaccumulation of nickel in animal products, such as milk, meat, and eggs.
Nickel Content in Animal Products:
The nickel content in animal products can vary depending on the animal’s exposure levels and the concentration of nickel in their diet. Studies have shown that nickel concentrations in animal products can be influenced by factors such as the duration and level of exposure, as well as the species and age of the animals.
Potential Health Risks for Humans:
The consumption of animal products with elevated nickel levels can pose health risks for humans. Nickel is classified as a human carcinogen by the International Agency for Research on Cancer (IARC) when inhaled, but its carcinogenicity through oral exposure is still a subject of ongoing research. Additionally, nickel exposure has been associated with adverse effects on human health, such as respiratory problems, skin allergies, and immune system dysregulation.
Nickel Allergy and Sensitization:
Individuals with nickel sensitivity or allergies can experience adverse reactions when exposed to nickel through food consumption. Nickel allergy is a common condition, and individuals with this allergy may experience skin rashes, itching, and other allergic reactions after consuming foods with high nickel content.
Regulatory Limits and Monitoring:
To safeguard human health, regulatory agencies worldwide have established maximum permissible limits for nickel in food products. Monitoring nickel levels in animal products is essential to ensure compliance with these regulatory limits and guarantee food safety.
Adverse Effects on Livestock Workers:
Livestock workers who handle animals exposed to high levels of nickel may also be at risk of occupational exposure. Nickel-containing dust and particles in the animal environment can be inhaled, leading to respiratory issues and potential health concerns for workers.
Importance of Risk Assessment:
Conducting risk assessments for nickel exposure in both livestock and human populations is critical. These assessments consider factors such as nickel content in animal products, human dietary habits, and potential health effects. Risk assessments aid in developing evidence-based guidelines to ensure food safety and mitigate potential health risks.
The human health implications of nickel toxicity in livestock underscore the importance of understanding the transfer of nickel from animals to humans through the food chain. Monitoring nickel levels in animal products, conducting risk assessments, and establishing regulatory limits are essential measures to ensure food safety and protect human health. By addressing the potential risks associated with nickel exposure in livestock, we can safeguard both animal and human well-being in agricultural environments at risk of nickel contamination.
8. Future Research Directions:
Future research directions in the field of nickel-induced toxicity in animals are essential to advance our understanding of this complex issue and develop effective strategies for prevention and management. The following research directions hold promise in bridging existing knowledge gaps:
Mechanisms of Nickel-Induced Toxicity:
Elucidating the underlying mechanisms of nickel-induced toxicity in different livestock species is crucial. Understanding how nickel interacts with cellular components, enzymes, and signaling pathways can provide valuable insights into its toxic effects. Investigating the oxidative stress pathways and inflammatory responses triggered by nickel exposure can also shed light on the pathogenesis of nickel toxicity.
Identification of Biomarkers for Early Detection:
Developing reliable biomarkers for early detection of nickel toxicity in animals can significantly improve diagnostic capabilities. Biomarkers could be specific molecules, proteins, or genetic markers that are indicative of nickel exposure and its adverse effects on animal health. These biomarkers can be detected in various biological samples, such as blood, urine, and tissues, enabling early intervention and timely preventive measures.
Assessing Long-Term Effects of Nickel Exposure:
Long-term studies focusing on the chronic effects of nickel exposure in animals are necessary to understand the cumulative impact of nickel over time. Investigating the potential for bioaccumulation and the persistence of nickel in animal tissues can provide insights into the long-term health consequences of continuous exposure. Additionally, studying the reproductive and developmental effects of nickel toxicity can help assess its impact on future generations of animals.
Understanding species-specific responses to nickel exposure is essential, as different animal species may exhibit variations in susceptibility and sensitivity to nickel toxicity. Comparative studies across multiple livestock species can provide valuable data on their unique responses to nickel exposure, facilitating tailored preventive measures for each species.
Nickel Interaction with Other Elements:
Studying the interactions between nickel and other elements, such as essential trace minerals, is crucial to comprehend how nickel may affect nutrient absorption and metabolism. Research in this area can help determine potential antagonistic or synergistic effects between nickel and other minerals and their impact on animal health.
Environmental Factors Influencing Nickel Toxicity:
Assessing the influence of environmental factors, such as pH, temperature, and soil characteristics, on the bioavailability and toxicity of nickel in the animal environment is vital. Understanding how these factors modulate nickel uptake by plants and subsequent exposure to animals can aid in devising appropriate soil management strategies.
Effects of Nickel Exposure on Gut Microbiota:
The gut microbiota plays a crucial role in animal health and metabolism. Investigating the effects of nickel exposure on gut microbiota composition and functionality can provide insights into potential disruptions in gut health and nutrient utilization.
Intervention Strategies and Mitigation Measures:
Conducting research to evaluate the effectiveness of various intervention strategies and mitigation measures in preventing or reducing nickel toxicity in livestock is essential. These may include supplementation with dietary chelating agents, developing low-nickel feed formulations, and exploring phytoremediation techniques to reduce nickel accumulation in forages.
Future research directions in nickel-induced toxicity in animals offer significant opportunities to advance our knowledge of this complex issue. Investigating the mechanisms of nickel toxicity, identifying early detection biomarkers, assessing long-term effects, understanding species-specific responses, and evaluating intervention strategies are critical steps in developing evidence-based solutions to mitigate the adverse effects of nickel exposure in livestock. Collaboration between researchers, veterinarians, and regulatory bodies is essential to address these research priorities and develop sustainable approaches for preventing and managing nickel toxicity in animals.
In conclusion, nickel toxicity in animals is a multifaceted issue that requires careful consideration to protect livestock health and ensure food safety. Throughout this review, we have explored the various aspects of nickel toxicity in animals, including sources of exposure, absorption and distribution in animal bodies, toxic effects on different livestock species, diagnostic challenges, and preventive measures. Understanding the complexity of nickel toxicity enables us to develop effective strategies to mitigate its adverse effects on animals and, subsequently, on human health.The primary sources of nickel exposure in livestock include contaminated feed, water, soil, and air. Implementing preventive measures, such as monitoring nickel levels in feed and water sources, adopting soil management techniques, and ensuring proper waste disposal, is crucial in reducing the risk of nickel toxicity in livestock. By identifying and addressing potential sources of nickel exposure, farmers and livestock owners can create a safer environment for their animals and minimize the risk of transferring nickel through the food chain to humans.Clinical signs of nickel toxicity in animals can be nonspecific, making diagnosis challenging. Veterinary monitoring and consideration of environmental exposure history are essential for accurate diagnosis and timely intervention. Timely detection and treatment can prevent further health complications and mitigate the impact of nickel toxicity on livestock.The transfer of nickel from animals to humans through the consumption of animal products raises food safety concerns. Regular monitoring of nickel levels in animal products and conducting risk assessments are crucial in ensuring compliance with regulatory limits and guaranteeing food safety for consumers. Awareness of nickel allergies and sensitization is also vital in protecting individuals who may have adverse reactions to nickel-containing foods.
Future research directions in nickel-induced toxicity in animals hold promise in advancing our understanding of this issue. Investigating the mechanisms of nickel-induced toxicity, identifying biomarkers for early detection, and assessing the long-term effects of nickel exposure are critical areas of research. Understanding species-specific responses, interactions with other elements, and the impact on gut microbiota can further enhance our knowledge in this field and inform targeted intervention strategies.In conclusion, addressing nickel toxicity in animals is a shared responsibility involving farmers, veterinarians, researchers, regulatory bodies, and consumers. By understanding the sources of exposure, potential health impacts, and implementing preventive measures, we can safeguard animal well-being and human health. Through continued research, education, and collaboration, we can develop evidence-based approaches to prevent and manage nickel toxicity, promoting sustainable agriculture and food safety. Protecting livestock from nickel toxicity not only ensures their health and welfare but also enhances the safety and quality of animal-derived products for human consumption.