Amino acid requirements of fish: a critical appraisal of present values

• Published in: Aquaculture Vol. 124; no. 1; pp. 1 - 11
• Main Author: Cowey, C.B.
• Format: Book Review Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 01.07.1994; Elsevier Science; Elsevier Sequoia S.A
• Subjects: ACIDE AMINE ESSENTIEL; Amino acids; AMINOACIDOS ESENCIALES; Animal aquaculture; Animal productions; BESOIN NUTRITIONNEL; Biological and medical sciences; Brackish; Diet; ESSENTIAL AMINO ACIDS; Fish; FISHES; Freshwater; Fundamental and applied biological sciences. Psychology; Marine; NECESIDADES DE NUTRIENTES; NUTRITIONAL REQUIREMENTS; PECES; Pisciculture; POISSON (ANIMAL); Vertebrate aquaculture; Nutrient requirement; Vertebrata; Aminoacid; Interspecific comparison; Pisces; Pisciculture; Review; Feeding
• ISSN: 0044-8486; 1873-5622
• DOI: 10.1016/0044-8486(94)90349-2

There are large variations in the measured essential amino acid requirements of different species of fish when expressed as a proportion of the diet. The question of whether or not these are real differences is considered. Dietary amino acids are needed for growth and for maintenance, and the former is quantitatively much the more important in young, rapidly growing fish. It is noted that the amino acids laid down during growth are sensibly the same in different species. Maintenance is considered to consist of losses from the integument and intestine, from oxidation of amino acids, from conversion of amino acids to other N-molecules and from protein turnover. Losses from these causes are considered and are not thought likely to differ appreciably between species. When amino acid requirements are expressed as a proportion of the dietary protein, differences, while reduced somewhat, are still wide. The dilemma is illustrated by reference to the differences in amino acid requirement values for rainbow trout from different laboratories. Factors likely to affect the overall performance of fish in requirement studies (water quality, different sources of amino acids and so on) are enumerated, but are not thought likely to explain the observed discrepancies. Dietary energy density is an important factor affecting amino acid requirement, but there are uncertainties surrounding metabolisable energy contents of major dietary components and this tends to preclude expression of amino acid requirement in terms of metabolisable energy. Other methods of assessing amino acid requirement are regarded as subsidiary to, and confirmatory of, growth data. Where amino acid deficiencies lead to tissue pathologies it is important that the stated requirement level is such as to prevent such pathologies. A table of requirement values for channel catfish and trout is provided; it is based on all published values but with greater weight being given to studies characterised by high rates of growth. The relative proportions of essential amino acids in the requirement pattern of the two species bear a strong similarity.