Compared with eel and mackerel, mackerel is more nutritious. Mackerel is rich in cytochrome C, vitamin C, etc.; the gastric mucosa contains hyaluronidase, vitamin B12, etc.; the pancreas contains insulin; the testes contain protamine; the eggs contain phospholipids, sterols, sphingolipids, etc.; and the liver contains vitamin A. , D, high nutritional value. Eel is mainly high in vitamin A, vitamin E and polyunsaturated fatty acids contained in fat. In comparison, mackerel is more nutritious.