Enriching Artemia nauplii with selenium from different sources and interactions with essential fatty acid incorporation

Abstract

The production of high-quality marine fish fry is limited by the low survival observed during the larval phase, which is often attributed to dietary deficiencies of the diets at first feeding. Despite progress made with live feed (i.e. rotifers, Artemia), enrichments in essential fatty acids for marine fish larvae, little is known on the micronutrient requirements such as selenium (Se). Se is a critical component of several enzymes maintaining important biological functions such as cellular oxidation, and therefore plays a key role in oxidative and stress status of marine larvae. The levels of Se found in the larvae's natural diet (i.e. copepods) is generally higher than those of the enriched live preys used in hatcheries. This study aimed at establishing a protocol to enrich Artemia nauplii with Se using different inorganic (sodium selenite) and organic (selenoyeast). Results indicated that the use of dissolved sodium selenite, an alternative inorganic and cheaper form of Se, did not increase the levels of Se in the nauplii. However, the use of selenoyeast (Sel-Plex) confirmed that it is possible to enrich the nauplii with targeted levels of Se, since this process followed a dose-response pattern with Se enrichment ranging from 1.7 to 12.4 mg kg-1. In addition, the supplementation of Sel-Plex to the regular enrichment product did not impact on lipids and fatty acids enrichment irrespective of the dose dispensed. Overall, this study contributes to the refinement of the live prey enrichment protocols that are critical to the success of marine finfish larviculture protocols.

Enhancement of Live Food Nutritional Status with Essential Nutrients for Improving Aquatic Animal Health: A Review

“…Enrichment of live food with selenium has been performed on rotifers [ 127 ] and Artemia [ 15 ] to meet the copepod Se levels. This element is transferred in the food chain to zooplankton and fish larvae [ 6 ].…”

“…However, Penglase et al [ 134 ] and Ribeiro et al [ 135 ] demonstrated that 2.1 and 3 mg of selenized yeast per 10 6 rotifers, respectively, in 3 h enrichments were needed to achieve the copepod Se levels. In the case of Artemia , 3 mg of selenized yeast per million individuals and 12 mg/L in 3 and 4 h enrichments, respectively, were needed to achieve the copepod Se levels [ 15 , 133 ]. These contrasts were probably due to the presence of other ingredients such as lyophilized algae, fish oil, and other commercial enrichment formulations.…”

“…It is important to understand the nutritional requirements of fish larvae in order to facilitate the optimization of diets and feeding protocols, which may subsequently enhance larval quality [ 7 , 14 ]. Consequently, several studies have emphasized developing practical methods to improve the nutritional status of live food with essential nutrients [ 15 , 16 , 17 , 18 , 19 , 20 ].…”

“…A very important aspect of live food enrichment is its reproducibility and predictability, which are crucial in commercial hatcheries. Hence, it is necessary to constantly produce high-quality live food on a large scale [ 15 ]. However, producing enriched live food with consistent levels of the important nutrients can be complex.…”

A New Approach for the Production of Selenium-Enriched and Probiotic Yeast Biomass from Agro-Industrial by-Products in a Stirred-Tank Bioreactor

“…Furthermore, the organic form of Se-enriched yeast can enhance the vaccine conferred immune response against the influenza virus in chicken [ 16 ]. Due to its importance in animal performance, most Se enrichment studies have been focused on the development of this mineral tolerance by microorganisms, plants, and small animals commonly used as feed such as yeasts [ 17 ], edible fungi [ 18 ], olive leaves [ 19 ], earthworms [ 20 ], rotifers [ 21 ], shrimps [ 22 ]. Among these groups, yeasts are well-known sources of organic Se for animals and play an important role in the industry as feed/food components and diet supplements.…”