Enhancing growth and development in olive flounder diets

by Tibiabin Benitez-Santana PhD, Aker BioMarine, Norway

 Making a good diet better
In the feed production industry, fish meal is in demand due to its high-quality protein, omega-3 fatty acids, and well-balanced amino acids. While the demand may be high, the production-levels are slowing, which has sparked a search for alternatives. One natural contender has stood out among the rest: krill meal from captured raw Antarctic krill (Euphausia superba).
 

Based on its nutritional profile, krill meal has the right total protein and ash contents, as well as amino acid profile, to make it one of the most comparable alternatives to fish. Over the years there have been several studies on the benefits of krill meal as a part of the diets of various species of fish, all with positive effects. A new study from researchers at Jeju National University’s Department of Marine Life Sciences reveals findings based on their experiment with fish meal supplementation in olive flounder diets.

Olive flounder are one of the most important fish species in South Korea, accounting for approximately 50 percent of the total finfish production. The objective of the olive flounder feed study was to determine how the fish were impacted by varying levels of krill meal in a low fish meal diet. The study specifically analysed the effect on growth performance, feed utilization, intestinal histology, digestibility, innate immunity, hematological parameters and disease resistance to Edwardsiella tarda, which is a serious bacterial pathogen in South Korean olive flounder farms.

Antarctic krill, a proven supplement in fish feeds
Krill is a marine-originated protein and phospholipid source that has shown through previous studies to be a successful supplement in fish feeds, as it lacks the unacceptable properties linked to plant proteins. Plant-derived protein sources have nutritional limitations such as low protein and high fibre content, imbalanced amino acid profiles and a wide range of anti-nutritional factors that negatively affect growth and health of the fish, as well as palatability of the feeds.

Krill meal is mainly produced from captured raw Antarctic krill, a crustacean related to shrimp. Krill aggregate in up to twenty-kilometers-long swarms and travel up and down a water column. Antarctic krill are one of 85 different species of krill around the world. They can be found in the Southern Ocean, with a nearly 500 million tonnes biomass, which means it has a huge potential among a number of under-exploited marine resources at lower tropic levels.

Krill are transparent animals with some red and green colorations; the red is due to astaxanthin pigmentation while the green is due to the algae in their digestive systems. Antarctic krill is harvested in the wild, cooked, dried and ground in order to create a powder consisting of proteins, phospholipids, omega-3 fatty acids and astaxanthin.

Read more, HERE.

The Aquaculturists

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