Nutrition and health of aquaculture fish

Abstract

Under intensive culture conditions, fish are subject to increased stress owing to environmental (water quality and hypoxia) and health conditions (parasites and infectious diseases). All these factors have negative impacts on fish well-being and overall performance, with consequent economic losses. Though good management practices contribute to reduce stressor effects, stress susceptibility is always high under crowded conditions. Adequate nutrition is essential to avoid deficiency signs, maintain adequate animal performance and sustain normal health. Further, it is becoming evident that diets overfortified with specific nutrients [amino acids, essential fatty acids (FAs), vitamins or minerals] at levels above requirement may improve health condition and disease resistance. Diet supplements are also being evaluated for their antioxidant potential, as fish are potentially at risk of peroxidative attack because of the large quantities of highly unsaturated FAs in both fish tissues and diets. Functional constituents other than essential nutrients (such as probiotics, prebiotics and immunostimulants) are also currently being considered in fish nutrition aiming to improve fish growth and/or feed efficiency, health status, stress tolerance and resistance to diseases. Such products are becoming more and more important for reducing antibiotic utilization in aquafarms, as these have environmental impacts, may accumulate in animal tissues and increase bacterial resistance. This study reviews knowledge of the effect of diet nutrients on health, welfare and improvement of disease resistance in fish.

Fish Nutrition and Current Issues in Aquaculture: The Balance in Providing Safe and Nutritious Seafood, in an Environmentally Sustainable Manner

“…However, sick fish generally do not feed vigorously and therefore may not consume enough medicated feed to ensure proper dosage. The use of antibiotics in aquaculture is also problematic because of the potential to develop antibiotic resistant bacteria, the presence of antibiotic residues in seafood, destruction of microbial populations in the environment and suppression of the fish immune system [51,52]. Therefore, research has focused on functional constituents in feeds to improve growth, feed efficiency, health status, stress tolerance and resistance to disease to reduce antibiotic utilization in farms.…”

“…Dietary supplementation of different non-digestible feed additives, such as immunostimulants, probiotics and prebiotics have been found to be beneficial for improving immune status, feed efficiency and growth performance in various different fish species. Feeding animals with immunostimulants prior to an infection or in situations known to result in stress will elevate defences and thus provide protection against otherwise potentially severe or lethal conditions [52]. Probiotics are live microbial organisms, non-pathogenic and non-toxic, which beneficially affect intestinal microbial products, reduce gut pH and release chemicals with bactericidal effects on other microbial populations, thus improving the immune response.…”

Impact of brewer's yeast extract and levamisole in diets with vegetable oils on the growth, chemical composition, and immunological and biochemical blood parameters of pikeperch (Sander lucioperca)

“…Very high quantities of linoleic acid (LA, 18:2 n-6), which dominates in some VO, suppress lysozyme activity in grouper (Epinephelus malabaricus) (Lin and Shiau 2007) and lower immunity functions in juvenile pikeperch . However, diets supplemented with synthetic or natural substances that activate cellular and humoral immunity can improve fish resistance and rearing parameters (Gopalakannan and Arul 2006;Li et al 2006a, b;Oliva-Teles 2012).…”

“…Natural substances in yeast cells, such as oligosaccharides and glucans, are biologically active and stimulate fish immune systems (Oliva-Teles 2012). An extract derived from Saccharomyces cerevisiae cells that are rich in nucleotides is available as the commercial product NuPro ® (Alltech Inc., USA).…”

Alterações histológicas no epitélio intestinal de juvenis de dourado <em>Salminus brasiliensis</em> alimentados com dietas contendo fontes proteicas vegetais

“…A farinha de peixe (FP) é ainda a principal fonte proteica utilizada na alimentação de peixes carnívoros em função do alto conteúdo em proteína (51 a 72 %), perfis adequados de aminoácidos (lisina, metionina, treonina e triptofano) e bom teor de fósforo (Oliva Teles, 2012). É um produto derivado do principalmente processamento de resíduos do pescado marinho, tais como cabeças, nadadeiras e vísceras.…”