There is no fish food for all fish.
From Fish Nutrition PB Presentation
Basic Food Components – Nutrition
• The immense variety of cultured finfish species hampers efforts to simplify production industry wide. Approximately 170 taxa are currently cultured, including carnivores, herbivores, planktivores, and omnivores, each posing its own set of nutritional demands .
• Fish meal has proven to be an excellent dietary protein source for finfish, leading to its description as an ‘‘ideal protein.’’ The ideal protein concept is based on the premise that if the amino acid profile of the feed mimics the whole-body amino acid profile of the animal being fed, protein utilization and growth should be maximized
• Lipids, fatty acids, and their derivatives play a role in virtually every physiological process that occurs and for this reason dietary lipid composition and content represent a massive sector of overall nutrition. Nowhere is this more true than in finfish nutrition where lipid can exceed protein in the body composition of finfish, a testament to the physiological and energetic importance of this nutrient class (Tocher2003). Aside from physiological importance, lipids are indispensable energy sources, especially for finfish, which are not well-adapted to carbohydrate utilization.
• Dietary protein and energy must be kept in proper balance because a deficiency or excess of dietary energy can reduce growth rates. Fish fed diets deficient in energy will metabolize more expensive dietary protein to meet energy requirements. Excess dietary energy can decrease protein intake and suppress growth.
• finfish do not require carbohydrates in their diet, … complex carbohydrates cannot be digested and utilized efficiently by most finfish species. A general dichotomy exists in the carbohydrate digestive ability of warmwater omnivores and herbivores versus the inability of coolwater and coldwater carnivores, which lack the appropriate function necessary for digestion of carbohydrates.
• For this reason, diets fed to these fish rarely contain more than 20% complex carbohydrate
• Conversely, warmwater omnivores or herbivores (e.g., channel catfish, tilapia, common carp, and white sturgeon) adapt well to diets containing as much as 40% dietary carbohydrate .
• Although vitamins and minerals are required in minute amounts compared with protein, lipid, and so forth, they are critically important, … Every micronutrient has a deficiency disease associated with it, the effects of which are sometimes irreversible or fatal. For a few vitamins and most minerals, excess can be equally detrimental, resulting in toxicity.
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