It is a general term for various hormones that can regulate the endocrine mechanism of animals and make nutrients that enter the body and redistribute them in a beneficial direction according to the needs of human growth of animals. Hormones only regulate (increasing or decreasing) the rate of certain physiological reactions, but do not provide the energy of the reaction process by itself, nor can they initiate new metabolic reactions. Therefore, when the original reaction is excessively stimulated, it is as harmful as when the hormone is deficient. In the past, thiouracil, iodinated protein, and diethylstilbestrol were used as feed growth hormones for additives, but they were quickly found to have side effects and were banned. Nowadays, as a feed additive, the growth hormone, with a molecular weight of about 22,000, is a pituitary hormone, which is a single-chain polypeptide molecule consisting of 191 amino acids in a certain order and can be extracted from the pituitary. It can also be produced by DNA recombination technology. Growth hormone acts on the whole body and plays a role in protein synthesis, glucose metabolism, regulation of renal function (glomerular filtration rate) and water metabolism, and increase the permeability of cells to amino acids, thus promoting the body (bone, muscle and The growth of organs). This hormone has interspecies specificity. The growth hormone present in cattle is only effective for cattle. It is used in xenobiotics, and it does not only promote growth, but also has adverse reactions. After oral administration, this hormone is destroyed by digestive enzymes and decomposed into amino acids and becomes ineffective. Often, the entire protein molecule is not used, and as long as 38 to 40 amino acid fragments, even smaller peptides are active, they promote the growth of young animals, prevent dwarfism caused by small amounts of growth hormone secretion, and animals with raw milk tissue. Can increase the amount of milk. In addition, research on growth hormone in pigs has progressed, and injection into piglets can promote growth and increase lean meat. The mechanism of action of hormones is quite different from that of general feed additives. Therefore, it is difficult to judge the overall advantages and disadvantages of the general feeding test and metabolic test. It needs to be comprehensively evaluated from the perspectives of endocrinology, toxicology and genetics. In addition, countries and regions with tight protein resources should consider their nutritional resources background and actual economic effects. Under low nutrient levels, growth hormone is often difficult to achieve the desired results.