Radha Bai, Department of Animal Nutrition, LUVAS, Hisar
Komal, Department of Livestock Production and Management, LUVAS,
Shabnam, Department of Animal Nutrition, LUVAS, Hisar
Fishmeal has been included in poultry diets for decades. There are two basic sources of fishmeal. The first is fishery waste that is a byproduct of processing fish caught specifically for human consumption and second source includes fish caught specifically for production of fishmeal. Fish meal has provided a major part of protein sources in poultry feeds because of its excellent protein quality.
Level of inclusion- But the use of fishmeal is usually restricted to 5% to 10% of the content of poultry diets. The main factor responsible for using limited amount of fish meal is the concentration of fish oil.
With 10% oil, adding 10% fish meal in any diet gives 1% fish oil, which is the maximum poultry will tolerate before they start rejecting feed or producing eggs with “fishy” aroma. In fact, it was not so much the fishy aroma of feeds that caused broilers go off feed easily but rather than rapidity with which fish oil become rancid and stale, fish oil stinks. The proteins in improperly stored fishmeal can also begin to break down, resulting in increasing levels of biogenic amines such as histamine. Consumption of high levels of histamine can cause gizzard erosion in chickens.
Nutritive value of fish meal – Fishmeal is a natural balanced feed ingredient that is high in protein, energy, minerals (calcium and phosphorus), a natural source of vitamins. The crude protein content of fish meal is above 65%, fat is around 8-11% and ash generally below 12%. It is a rich source of essential amino acids required for animal growth and maintenance, especially lysine, methionine, threonine and tryptophan. These are present in a readily digested form. Lysine is often the first limiting amino acid when poultry diets are formulated from cereals and vegetable proteins. Fishmeal is not only a good source of lysine but also highly digestible. It also has a good balance of unsaturated fatty acids, certain minerals (available phosphorus), and vitamins (A, D, and B-complex).
Why fish meal so popular- Fish meal was so popular because the ratio of price to nutritive value was exceptional. At a price that today is closer to full-fat soybeans, fish meal offered double (almost) the protein, a better amino acid profile and a boost in feed intake that was not to be found in other ingredients. In fact, one of the ingredients that helped in the transition to antibiotic-free feeds was fish meal. Fishmeal, and fish oil, are unique and are now virtually the sole sources of the very long chain omega-3 fatty acid in the diet of animals.
Pros of using fish meal- Fish meal remains an excellent source of protein, and if it is of the best quality, it will still improve feed intake. Thus, when one is faced with animals suffering from low feed intake problems, or wants to supplement a protein source of exceptionally low cost, then using fish meal remains a good option. Perhaps it is not feasible to use fish meal in all poultry diets and, as such, its use should be limited to super sensitive diets, such as those destined for broilers in the first days post-hatch (super pre-starter diets), when birds recover from a gut damaging disease or when feed intake is hampered by a bitter or other undesirable ingredient. In brief, using fish meal has become a tool to overcome problems rather than a dependable source of proteins.
Cons of using fish meal- Fish meal is often the preferred source of protein because of the balance of essential amino acids. Main concern about fish meal is its quality (mostly rancidity but also putrefaction of proteins due to improper storage of fish before processing into fish meal). One also has to consider the social/environmental image or impact when using an ingredient that is depleting wild stocks of fish, but such scruples also affect those industries that use up current quantities of fish meal without much regard to its cost. Fish meal spread diseases, such as Salmonella, are not new or novel. Any animal or otherwise ingredient can become a carrier of disease microorganisms, and excluding one or the other has not stopped diseases from spreading. It is lack of proper quality control and not specific ingredients that cause this kind of problem. So, to achieve economic rates of growth or egg production, fish meal is often the preferred source of high-quality protein because of the balance of essential amino acids. But high levels of fishmeal in poultry diets can result in fishy meat and eggs. The use of fishmeal, therefore, is typically restricted to 5-10% of poultry diets.