Nutrition and Metabolism of Minerals in Fish

Abstract

Aquatic animals have unique physiological mechanisms to absorb and retain minerals from their diets and water. Research and development in the area of mineral nutrition of farmed fish and crustaceans have been relatively slow and major gaps exist in the knowledge of trace element requirements, physiological functions and bioavailability from feed ingredients. Quantitative dietary requirements have been reported for three macroelements (calcium, phosphorus and magnesium) and six trace minerals (zinc, iron, copper, manganese, iodine and selenium) for selected fish species. Mineral deficiency signs in fish include reduced bone mineralization, anorexia, lens cataracts (zinc), skeletal deformities (phosphorus, magnesium, zinc), fin erosion (copper, zinc), nephrocalcinosis (magnesium deficiency, selenium toxicity), thyroid hyperplasia (iodine), muscular dystrophy (selenium) and hypochromic microcytic anemia (iron). An excessive intake of minerals from either diet or gill uptake causes toxicity and therefore a fine balance between mineral deficiency and toxicity is vital for aquatic organisms to maintain their homeostasis, either through increased absorption or excretion. Release of minerals from uneaten or undigested feed and from urinary excretion can cause eutrophication of natural waters, which requires additional consideration in feed formulation. The current knowledge in mineral nutrition of fish is briefly reviewed.

Assessment of Fish Quality Based on the Content of Heavy Metals

“…They are components of many enzymes and take part in many life processes. They are involved in the synthesis of hormones and other substances, helping to regulate the growth, development and functioning of the reproductive and immune systems [ 19 , 20 , 21 , 22 ]. Trace elements can cause harmful health effects when they accumulate in organisms in concentrations above those required for metabolic functions.…”

Thyroid Hormones in Hemolymph of Red King Crabs from the Barents Sea

“…Deiodination of T4 leads to production of T3 and reverse T3 (rT3) [2]. Thyroids play a crucial role in regulating early development, metamorphosis, and metabolism in mammals, amphibians, and Animals 2022, 12, 379 2 of 11 fish, and most vertebrates are unable to grow and reach their normal adult form without them [3][4][5][6]. Non-vertebrate chordates, such as tunicates, cephalochordates, and the larvae of lampreys have the endostyle, which acts as a thyroid gland homolog [7,8].…”

PAMPs of Piscirickettsia salmonis Trigger the Transcription of Genes Involved in Nutritional Immunity in a Salmon Macrophage-Like Cell Line

“…In marine fish, micronutrients such as iron, manganese and zinc are absorbed by the gills and the gastrointestinal tract, having catalytic, structural, physiological and regulatory functions ( 20 ). Therefore, it is not surprising that microorganisms have developed sophisticated mechanisms to sequester these micronutrients and use them to survive ( 5 ).…”