Animal Nutrition

Challenges of protein diet for fish

Protein nutrition is a determining factor for increasing productivity

In fish farming, food is one of the most important factors for efficient and healthy animal growth. However, there are some challenges regarding their nutrition.


Proteins are the main constituents of muscle tissue and when digested are hydrolysed into free amino acids to be distributed to organs and tissues through the bloodstream, forming new proteins for growth, reproduction and sustenance.


Foods with insufficient protein content can slow down growth, compromise food efficiency, and induce immunosuppression by mobilizing protein from some other tissues to maintain other vital functions. Therefore, proteins are considered one of the main nutrients for the body at all stages of fish life.

Amino acid nutritional requirements

Amino acids act as protein structure subunits and are precursors of coenzymes, hormones, nucleic acids and other essential molecules for proper body functioning.


In general, they are used for reconstituting their own proteins, and a sufficient and balanced amount of different essential amino acids is indispensable. In the case of diets formulated by a natural source of protein, some amino acids may be present but in insufficient amounts. If this happens, the body will not be able to use all amino acids effectively.


As essential amino acids are not synthesized by the body, they can limit the synthesis of proteins, muscles and tissues.


So as to ensure a healthy and adequate pattern of protein synthesis, a satisfactory dietary intake or an increase in essential amino acids is required.

High levels of protein must be watched

Excess protein in the diet can result in increased nitrogen excretion, even if it is used for growth or to meet energy needs. Carnivorous fish need a diet with high levels of protein because of their short intestine.


On the other hand, omnivores have less demand because of their longer intestine, making the food remain in contact with the enzymes for longer, increasing digestion efficiency to compensate for the low nutritional value of the food ingested.


It is extremely important to understand the nutritional requirements of amino acids for each species and life cycle stages. Response-dose experiments are classic and accurate tools for determining animal requirements. Using the ideal protein concept, so that the estimation of the requirements can be made in the simplest way, it is an alternative to obtain better performance of the animals.

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