Nitrite is an inorganic compound containing nitrogen and oxygen, and its chemical formula is NO2-. Nitrite is widely found in nature, but excessive nitrite can cause serious harm to animal health. So, where does nitrite in feed come from? What effect does it have on the animals? Let's take a look.
Nitrite hazards.
After nitrite enters the animal's body, it will combine with hemoglobin to form methemoglobin, which will make hemoglobin lose its oxygen-carrying capacity, resulting in hypoxia in animals, and symptoms such as dyspnea, malaise, decreased appetite, weight loss, and even death in severe cases. This is how nitrite poisoning manifests. Nitrite-poisoned animals have chocolate-colored blood, dark red or brown muscles, and brown or red urine. Nitrite poisoning can also affect the reproductive ability of animals, leading to miscarriages, stillbirths, malformed fetuses, etc. In addition, nitrite reacts with amines to form carcinogenic nitrosamines, which are harmful to animal health.
Nitrite**.
The nitrite in the feed mainly comes from the following aspects:
Nitrite in the soil. Organic nitrogen in the soil is converted into ammonia, nitrite and nitrate by microorganisms, which is a dynamic equilibrium process. When nitrite levels in the soil exceed the plant's ability to use it, it accumulates in the plant, especially in leafy feed. The nitrite content in the soil is affected by a variety of factors, such as fertilizer application, irrigation water quality, soil pH, temperature, humidity, etc.
Processing and storage of feed. Feed processing and storage can also lead to nitrite production if the conditions are not suitable. For example, nitrate in feed will be reduced to nitrite under reducing conditions; The nitrite in the feed is oxidized to nitrate under oxidizing conditions. Therefore, the processing and storage of feed should pay attention to controlling temperature, humidity, ventilation, mildew, etc., to avoid feed deterioration.
Feed additives. Some feed additives also contain nitrites or substances capable of producing nitrites. For example, some preservatives, antioxidants, pigments, etc. Under certain conditions, these additives react with other components in the feed to form nitrite. Therefore, the use of feed additives should follow the relevant regulations, control the dosage, and avoid excess.
Conversion pathways of nitrite.
After the nitrite in the feed enters the animal, it will be transformed through the following ways:
Nitrite reductase pathway. This is the main conversion pathway of nitrite in animals. Nitrite reductase is an enzyme found in animals that reduces nitrite to ammonia and oxygen. This process requires the consumption of reducing agents such as glutathione, vitamin C, etc. This pathway can reduce the toxicity of nitrite, but it also depletes the antioxidants in the animal's body, affecting the animal's ability to resist disease.
Nitrite oxidase pathway. This is the secondary conversion pathway of nitrite in animals. Nitrite oxidase is an enzyme found in animals that oxidizes nitrite to nitrate. This process requires the consumption of oxygen to produce nitric oxide and nitric peroxide. This pathway can reduce the toxicity of nitrite, but it can also produce some harmful free radicals that can damage animal cells.
Nitrite binds to hemoglobin pathway. This is the most dangerous conversion route for nitrite in animals. Nitrite can combine with the iron ions in hemoglobin to form methemoglobin, which makes hemoglobin lose its oxygen-carrying capacity, resulting in hypoxia in animals. This pathway is the main cause of nitrite poisoning.
Nitrite binding pathway to amines. This is another dangerous conversion pathway for nitrite in animals. Nitrite can combine with amines in feed or animals to form carcinogenic nitrosamines. This pathway is the main cause of nitrite carcinogenesis.
Nitrite control measures.
In order to prevent nitrites in feed from causing harm to animals, we can take some of the following measures:
Detection and analysis of nitrites。In order to detect the nitrite content in the feed in time, we should regularly test and analyze the feed. There are many methods of detection and analysis, such as colorimetry, spectrophotometry, ion chromatography, gas chromatography, etc. The principles and operations of these methods are complex and require specialized instruments and personnel. We can choose the appropriate method according to our own conditions and needs to ensure the accuracy and reliability of the detection.
Degradation and removal of nitrites。In order to reduce the nitrite content in the feed, we can use a number of physical, chemical or biological methods to degrade and remove the feed. The physical method is to use high temperature, high pressure, ultraviolet rays, etc., to decompose nitrite into harmless substances. The chemical method is to convert nitrite into other substances by using reducing agents, oxidants, complexing agents, etc. The biological method is to use microorganisms, enzymes, plants, etc., to degrade or absorb nitrite. The effect and applicability of these methods have certain limitations, and it is necessary to choose a reasonable method according to the specific situation to avoid secondary pollution or loss.