Can microalgae Pavlova be a potential ingredient in salmon aquafeeds?

Scientist assesed the suitability of Pavlova produced in photobioreactors for potential use in salmonid aquafeeds.

Can microalgae Pavlova be a potential ingredient in salmon aquafeeds?

November 27, 2019

Microalgae can be regarded as a promising alternative that can replace fishmeal and fish oil and ensure sustainability standards in aquaculture. They can be used as a source of protein, lipid, vitamins, minerals, pigments, etc.

Pavlova sp. 459 has been used as a high-quality liquid live-feed for cultivated bivalves, but never was evaluated as a low-trophic dry aquafeed ingredient. A group of Canadian researchers evaluated it for nutritional characteristics relevant for salmonid aquafeeds.

Pav459 was batch-cultivated in photobioreactors and prepared as an intact-cell meal (direct freeze-drying) and a cell-ruptured meal (freeze-drying following microfluidic high-pressure homogenization). Protein quality was based on essential amino acid (EAA) profiles, chemical scores, and in vitro 2-phase gastric/pancreatic digestion (GPD) for salmonids.

Nutrients were well-preserved after processing and meals contained 66% protein, 16% lipid, 7% carbohydrate, 24 MJ kg-1 DW energy, and 11% ash. Protein quality of the meals was good as indicated by their high EAA/non-EAA ratios, high EAA indices of 0.82ā€“1.06 (relative to egg albumin, premium fishmeal and soy protein), high chemical scores (1.4ā€“2.2) for most EAAs (calculated against published salmonid dietary requirements), and high in vitro GPD (82%), irrespective of cell-rupture.

Pav459 meals contained health-promoting compounds (fucoxanthin, 358ā€“368 mg (100 g)-1 DW; lutein, 101ā€“162 mg (100 g)-1 DW; total phenolic compounds, 33 mg gallic acid equivalents gāˆ’1 DW) with negligible contaminating heavy metals and anti-nutritional factors.

Pav459 lipid was highest in PUFA (> 60% of FAME), most of which was nutritionally superior n-3 series (50ā€“52% of FAME) relative to n-6 series (10% of FAME). In addition, the vast majority of n-3 PUFA (81%) was comprised of essential LC-PUFA, eicosapentaenoic acid at 3% of the meals and docosahexaenoic acid at 2% of the meals.

Check full study here.


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