Foundations of Fish Nutrition

Foundations of Fish Nutrition

Aquaculture plays a significant role in supplying animal protein of excellent biological value to consumers in the brazilian national production context, with particular emphasis on tilapia farming.

This species is the flagship of the activity, and among all the favorable characteristics for its cultivation, its fillet stands out as a noble element with light coloration, mild flavor, and absence of “Y” bones, facilitating its consumption. This versatility allows for the preparation of various recipes for consumption.

However, despite these notable attributes, there are various stages and processes involved before this fish makes its way to the consumer’s plate, with fish nutrition and feeding on the farms standing out as fundamental components in this chain.

Well, then, how can we ensure that confined fish receive all the necessary nutrients correctly for their productive or reproductive performance and maintenance??

Firstly, it is essential to recognize these nutrients and how they can be efficiently allocated to the particular species. It is well-established that the most critical macronutrients for fish are: [register]

Protein and lipids play primary roles, with carbohydrates acting as a supporting component (the physiological and metabolic mechanisms of this category require further study to understand how they function); meanwhile, fundamental micronutrients include vitamins and minerals.

From this point, details such as the developmental stage of the fish and production objectives become decisive, as these factors will guide the formulation of a diet. Therefore, understanding the nutritional requirements is a key point in balancing feeds, as any imbalance in the formulas can impact the fish’s performance.

Thus, feeds have become much more precise, and most importantly, the impact they have on both the productive performance of the animals and the maintenance of the production environment is crucial.

Considering that the metabolism of this macronutrient ultimately leads to nitrogen excretion, one of the primary substances responsible for eutrophication (nutrient increase) of the environment where the fish are located.

Therefore, with the ongoing advancement of knowledge, we have reached the provision of feeds that are increasingly precise in terms of amino acid composition, responsibly balancing essential amino acids.

Although feeds are commonly referred to by their manufacturer or crude protein content, it’s worth remembering that other elements are integral and deserve significant attention during formulation and processing.

Furthermore, and equally significant, lipids are essential components because they serve various functions in organisms, including:

Furthermore, various fish species have distinct requirements for essential fatty acids, primarily because of the absence of desaturase and elongase enzymes, which can produce long-chain carbon molecules with double bonds in their carbons.

Understanding the physiological functioning of lipids is crucial for providing elements that enable animals to efficiently produce fundamental molecules for their development and, thereby, utilize available resources to promote both lipogenesis and lipolysis effectively.

The last macronutrient included in fish diets is carbohydrates. This nutrient serves as an interesting energy source for living organisms and is also available as a reserve (glycogen) during periods of decreased serum glucose or during physical exertion.

Conversely, carbohydrates play a crucial role in feed processing. This is exemplified by the gelatinization of starch during extrusion, leading to decreased pellet density—thus enabling buoyancy—and enhancing the digestibility of this component. However, comprehending the metabolic pathways of carbohydrates in aquatic organisms is crucial yet remains obscure.

It is reasonable to assume that there might be similarities to terrestrial animals; however, there are still many uncertainties regarding this aspect up to the present moment.

Well, it’s practically impossible that the supply of macronutrients alone is sufficient for any developing organism.

This fact is underscored by the necessity to break down these molecules—whether they are polymers or not—into smaller units that can be assimilated and subsequently utilized for anabolism.

Vitamins, categorized as water-soluble—those soluble in water, encompassing all B-complex vitamins and vitamin C—and fat-soluble—those soluble in fat, represented by vitamins A, D, E, and K—play a fundamental role in the functioning and development of animals in general.

For instance, the cellular energy production process (ATP) is supported by thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), and pantothenic acid (vitamin B5). Body composition, or structural issues, relies on ascorbic acid (vitamin C) during the formation of collagen fibrils. On the other hand, retinol (vitamin A), cholecalciferol (vitamin D), and tocopherol (vitamin E) have regulatory and antioxidant functions, among others, while phylloquinone (one of the forms of vitamin K) is responsible for blood clotting.

Minerals, classified into macro minerals—required in larger quantities—and trace minerals—needed in trace amounts—play vital roles in bone and cell membrane formation. They function as electrolytes in intra and extracellular fluids, regulate osmotic balance, are involved in the formation of hemoglobin’s porphyrin ring, participate in hormone synthesis, and contribute to enzymatic structures, mediating diverse physiological functions.

Ultimately, grasping the fundamentals of nutrition is essential for successful aquatic organism production—particularly fish and shrimp. As previously mentioned, these animals inhabit confined environments, facing environmental fluctuations and high stocking densities. These conditions necessitate high-quality nutrition and precise feed management to help the fish navigate challenges effectively and achieve satisfactory zootechnical performance, among other goals.