Dr Rober Thillner, product manager, Aller Aqua, said the company is increasing looking at how to supply fish in the early life-stages with optimal and tailored feeds. We caught up with him at the show to hear more.
The cultivation of many fish species still relies on the provision of live feed in the early stages. In fact, the discovery and extensive use of rotifers and Artemia may have been the main driving force behind the tremendous growth in aquaculture production so far, he said.
Nevertheless, there is a move on now for manufactured diets to replace live feeds to a large extent.
And high mortality rates can occur in hatcheries if abiotic and biotic conditions are not within tightly framed optima, which is a consequence of the reproductive strategy of many teleost fish species, said Tillner.
A series of trials at Aller Aqua Research in Buesum, Germany indicated significantly higher growth, lower FCR and improved nutrient retention in fry of rainbow trout when fed a more energy-rich feed, reported the company.
Some fish species benefit from more energy-rich feeds such as fry of rainbow trout, whereas others thrive on feeds with less energy, said the product manager.
For the most delicate, early stages, the Danish firm is rolling out a new premium starter diet for fish larvae and early fry, Aller Infa Ex Gr, which is said to include high levels of krill meal. With particle sizes down to 0,1 mm, he said the fry feed is aimed at supporting healthy development, fast growth and high survival rates.
The larvae of many fish species are not fully developed at the time they start feeding, some lack a fully developed stomach with the complete range in digestive enzymes, and the digestion of feed particles as well as the nutrient uptake is of highest importance to match the high potential for growth, said the aqua feed specialist.
The company has also redesigned its Aller Futura Ex Gr feed, with a higher fat and energy content, focused on the nutritional requirements of rainbow trout and other salmonids, while its Aller Thalassa Ex Gr feed now has a balanced protein to fat ratio, more suited to larvae and fry of marine species as well as species with lesser energy requirements, it said.
The fry portfolio is designed to aid the developing fish in their digestive processes and organ development, leading to better secretion of digestive enzymes, improved nutrient uptake as well as improved growth and health of larvae and fry, said Aller Aqua.