Pig raising pig raising pig focus on raising, second in prevention, the last is to treat. In my opinion, the reason why many pig farmers are always on the run for "treatment" is "not raising well, not preventing well".
Full-price feed is easy to oxidize, especially the full-price feed rich in oil, if the storage conditions are not appropriate, the risk of oxidation over a long period of time is great.
Oxidation of feed oils is a natural phenomenon, whether or not you take control measures. In practice, we try to delay this process by minimizing oxidation before the animals eat, and by avoiding the reduction in feed intake caused by oxidative rancidity. Therefore, anti-oxidation work should be started before feed processing, including the selection of good raw materials and appropriate antioxidants.
How does rancidity work
Oxidation of fats, also known as rancidity, is a natural reaction between unsaturated fatty acids and oxygen. Unsaturated fatty acids are found in a variety of fats and oils, some vegetable oils such as soybean oil and peanut oil are abundant. For example, coconut oil has a ratio of more than 11 saturated to unsaturated fatty acids, but corn oil has a ratio of just 0.15. Oil with high unsaturated fatty acids is more likely to oxidize. Grease is more easily oxidized in the presence of air (open packaging), light, high temperatures, and certain metals such as iron and copper. The reaction occurs spontaneously, and once started, oxidized fatty acids continue to form and eventually superoxide.
Why is the palatability of the oxidized feed poor
Oxidized fatty acids, known as free radicals, react not only with other fatty acids but also with amino acids, making them unusable by animals. Methionine and tryptophan are particularly susceptible to free radical oxidation. Their limiting amino acids in the diet are usually added in the form of crystalline amino acids. In a comparative study, oxidation during peeling of wheat, sorghum, barley and oat reduced the bioavailability of methionine and tryptophan by 26%.
Anti-oxidation measures should be taken before feed production
Other side effects of oxidative rancidity include the formation of fishy and undesired flavors such as soybean meal, vegetable meal, and fish oil from ingredients rich in linolenic and linoleic acids. This process, called retrogression, can occur under anaerobic conditions and there is currently no way to prevent it.
It is obvious that oxidation of oil fortifiers is a problem. If the rancidity of lard is increased to 6%, the feed intake and growth rate of weaned pigs will be linearly inhibited. In the same study, dietary superoxides should not exceed 240mEq to prevent growth inhibition. Poultry, especially broilers, respond similarly. Adult chickens are less likely to respond to rancid disease, but adult animals are also less likely to be fed a high-oil diet.
Studies have shown that dietary superoxide concentrations should not exceed 240mEq to prevent growth
What antioxidants are used
Antioxidants are often added to the oil to prevent its automatic oxidation during the storage process. Such additives are also used in full-price, concentrated and premixed materials containing high oil content. As mentioned earlier, antioxidants only stabilize the activated fatty acids to delay the oxidation process, but over time, the fatty acids eventually react with oxygen. Common antioxidants are ethoxyquinoline, butylcresol, propyl gallate and vitamins C and E. The last three are too expensive to use as feed antioxidants, which are added to the feed for other reasons but also act as antioxidants.
Natural antioxidants are phenols extracted from some plants. Ingredients are found in cloves, cinnamon, oregano and chamomile. Many pigments, such as carotene, -carotene, astaxanthin, zeaxanthin, lutein, and keratoflavin, have antioxidant activity.
Quality control
All incoming grease ports must be tested for rancidity. If storage conditions are prone to rancidity, it is best to buy antioxidant-fortified oils. Full price materials should also be tested regularly. In addition, samples should be collected from the feed tank to assess the oxidation status of the feed during feeding.
Superoxide analysis is an effective indicator of rancidity, but it does not provide all the information needed to assess the oxidation status of feeds and fats. Other analyses included the detection of methoxyaniline, malondialdehyde and thiobarbisic acid (TBA). The analysis of combination index is helpful for us to understand the oxidation status comprehensively.
Practical advice
A low dose of a cheap antioxidant is often used to cope with general conditions, including cold weather during feed production and running out a few weeks after the feed is produced. Prolonged storage, storage and transportation under warm and hot conditions, and high unstable grease levels require special treatment. In this case, it is wise to use two or three different antioxidants. The first idea is to add antioxidants to the maximum recommended, but not recommended, unless unexpected rancidity occurs very quickly. Moderation is best.
