It has been suggested that the Pig Society serves the pig farmers, but these contents seem to have nothing to do with raising pigs, nor are they what the pig owners want. What I want to say is that raising pigs and raising pigs is focused on raising, followed by prevention, and finally in governance. However, many pig farmers are now struggling for "governance". In my opinion, the reason is "no good, no defense." Just like the topic of oxidative stress discussed in the next two days, don't think that this is what feed mills should care about. Stress, mycotoxin poisoning, rancidity of bran rice bran does not cause oxidative stress? Do you dare tell me these questions are not on your farm? Sadly, you don't know that this is the problem, I thought it has nothing to do with you!
Please pay attention to the relevant content of tomorrow!
Full-price feeds are easily oxidized, especially for full-price feeds rich in oils. If storage conditions are not appropriate, the risk of oxidation over time is high.
Oxidation of feed fats is a natural phenomenon, regardless of whether you take preventive measures. In reality, we want some ways to delay this process, to minimize oxidation before the animal feeds, and to avoid the loss of feed intake due to oxidative rancidity of the feed. Therefore, the work of preventing oxidation should begin before the feed processing, including the selection of good raw materials and suitable antioxidants.
How rancidity is carried out in the
Oxidation of oils and fats is also known as rancidity, which is a natural reaction between unsaturated fatty acids and oxygen. Unsaturated fatty acids are found in various fats and oils, and some vegetable oils such as soybean oil and peanut oil are abundant. For example, coconut oil has a ratio of saturated to unsaturated fatty acids of more than 11, but corn oil is only 0.15. Oils with high levels of unsaturated fatty acids are more susceptible to oxidation. Grease is more susceptible to oxidation when exposed to air (open packaging), light, high temperatures, and certain metals such as iron and copper. The reaction proceeds spontaneously, and once started, the oxidized fatty acids continue to form and eventually form superoxide.
Why the oxidized feed is poorly palatable
Oxidized fatty acids, also 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 oxidation by free radicals. They are limiting amino acids in the diet, usually they are added in the form of crystalline amino acids. In a comparative study, oxidation of wheat, sorghum, barley, and oats during peeling reduced the bioavailability of methionine and tryptophan by 26%.
Anti-oxidation measures should be taken before the production of feed
Other side effects of oxidative rancidity also include raw materials rich in linolenic acid and linoleic acid to form undesirable flavors such as fishy and raw bean flavors (such as soybean meal, rapeseed meal and fish oil). This process is called rejuvenation and can occur under anaerobic conditions. There is currently no way to prevent it.
It is obvious that the oxidation of the grease strengthening material is a problem. If the rancid lard is added to 6%, the feed intake and growth rate of the weaned pig will be linearly inhibited. In the same study, it was found that dietary superoxide should not exceed 240 mEq to prevent growth inhibition. Poultry, especially broilers, respond similarly, and adult chickens are relatively insignificant in response to rancidity, but in other words, adult animals rarely feed high-oil diets.
Studies have shown that dietary superoxide concentration should not exceed 240mEq, in order to prevent the growth of
What kind of antioxidants are used?
Antioxidants are often added to the oil to prevent auto-oxidation of the oil during storage. Such additives are also used in full-price materials, concentrates and premixes containing higher fats. As mentioned earlier, the antioxidant only stabilizes the activated fatty acid to delay the oxidation process, but as long as the time is long, the fatty acid will eventually react with oxygen. Common antioxidants are ethoxyquinoline, butyl cresol, gallic acid propylate, vitamin C, and vitamin E. The latter three are too expensive to use as feed antioxidants. They are added to the feed for other reasons, but at the same time they exert antioxidant effects.
Natural antioxidants are phenolic substances extracted from some plants. The product has ingredients extracted from clove, cinnamon, oregano and tansy. Many pigments, such as carotene, beta-carotene, astaxanthin, zeaxanthin, lutein and canthaxanthin, have antioxidant activity.
Quality control
All greases entering the plant must be tested for rancidity. If the storage conditions are prone to rancidity, it is best to purchase an antioxidant-fortified oil. Full price should also be tested regularly. In addition, samples should be collected from the trough to assess the oxidation status of the feed when the animals are fed.
Superoxide analysis is an effective indicator of rancidity, but it does not provide all the information to assess the oxidation status of feeds and fats. Other analyses also included methoxyaniline, malondialdehyde, and thiobarbituric acid (TBA) assays. Analysis of the combined indicators helps us to fully understand the oxidation status.
Practical advice
Low-dose additions of a cheap antioxidant are usually available to cope with the general situation, including cold weather during feed production and can be used up in a few weeks after feed production. Extended storage period, or storage and transportation under warm conditions, high levels of unstable oils require special treatment. In this case, it is wise to use 2 to 3 different antioxidants. The first idea is to add antioxidants to the highest recommended amount, but it is not recommended unless unanticipated rancidity occurs very quickly. The right amount of addition is the best.
Original title: How to control oxidation in finished feeds
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