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Protein Supplements of Animal Origin - Marine-Based Products

Fish meals constitute the majority of the marine-based high protein products fed to animals. Marine-based products originate from species acquired specifically for feedstuffs and as by-products of processing of marine species.

Fish meal is clean, dried, ground tissue from undecomposed whole fish or fish cuttings, either with or without extraction of a portion of the oil.

Figure 7.5 illustrates fish meal.

The maximum water content of fish meal is 10%. The maximum salt content is 7% salt. In addition, salt content will be stated when it is greater than 3%. Fish meal contains both a high quantity and a high quality protein. On an as-fed basis, crude protein content of fish meal is 57-77%; depending on the fish source. The protein quality of fish meal is excellent; high in essential amino acids, including lysine. In addition, fish meal is a good source of the B-complex vitamins and most of the minerals including calcium and phosphorus. The nutrients are also readily available. Nutritional value will be influenced by the type of raw material used to produce the fish meal and processing of the meal. In general, the nutritional value of quality raw materials, including a moderate fat content, adequately processed is good.

Processing may influence nutritional value, storage properties, and quality of the resultant product from the animal. Improper processing will reduce the availability of nutrients such as proteins. High levels of oil in fish meal will cause problems such as rancidity and off-flavors in resultant products. For monogastrics, excessive oil content in the meal will give a “fishy” flavor to the resultant products such as meat and eggs. Addition of antioxidants is also essential to prevent against rancidity.

For monogastrics, fish meal is a high quality protein source. However, fish meal is an expensive protein source. For ruminants, fish meal is an excellent source of rumen undegradable protein.

Other marine-based products are also available. Other marine-based products include fish residue meal, protein concentrate, liver and glandular meal, condensed solubles, dried solubles, by-products, condensed protein digest, dried protein digest, silage, and liquefied fish. Refer to page 102 of the text for a brief description of each of these products.

Additional marine-based products also include shrimp and crab meals. Shrimp and crab meals are by-products of the respective processing industries. The average crude protein content of shrimp and crab meal is 32% and 30% on an as-fed basis, respectively. The mineral content for crab meal is high at approximately 40% on an as-fed basis. The nutritional values of shrimp and crab meals are influenced by the chitin content. Chitin is a glycoprotein present in the exoskeleton of shrimp and crab.

Figure 7.6 illustrates the chemical structure of chitin. The Ac abbreviation represents an acetyl group or group containing a COCH3.

For monogastrics and ruminants, availability of chitin is low.

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