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Extrusion processing improves rainbow trout digestibility of microalgal Nannochloropsis oculata co-product biomass for more sustainable aquaculture diets



Details

  • Journal Title:
    Algal Research
  • Personal Author:
  • NOAA Program & Office:
    OAR (Oceanic and Atmospheric Research)
  • Description:
    Aquaculture feeds include fishmeal (FM) and fish oil (FO), derived from wild-caught marine fish such as anchovy and sardines, and pose ecological, food security, and economic drawbacks for sustainable aquaculture, the world's fastest-growing agricultural sector. Protein-rich microalgal co-product is a promising alternative to unsustainably sourced fishmeal in aquaculture diets. Microalgal co-product is a defatted biomass left over after extracting omega-3-rich oil for human nutraceuticals and crude oil for fuels. In this study, we report the first evaluations of nutritive values and digestibility of raw, extrusion- and enzymatic-processed co-product of the marine microalga Nannochloropsis oculata (N. oculata co-product). Results allowed us to evaluate the feasibility of using processed biomass in aquafeed for rainbow trout (Oncorhynchus mykiss), an important model for all salmonid aquaculture. Extrusion processing temperature (90 °C vs 127 °C) influenced the nutritional value of N. oculata. Protein and energy levels were significantly higher in co-product from both extrusion temperature treatments than in non-extruded raw co-product. Essential amino acid levels did not differ between extrusion temperatures, except that methionine was significantly lower in coproduct from 127 °C extrusion processing than from 90 °C extrusion processing. The protein level in extrusion processed co-product was not significantly influenced by pre-cooking. We detected the highest digestibility of crude protein, energy, most of the amino acids, and omega 3 polyunsaturated fatty acids (n3 PUFA) in extruded (90 °C) N. oculata co-product ingredient. Nutrient digestibility of enzymatic processed N. oculata co-product were mostly the same as extrusion processing or lower for certain nutrients. Overall, extrusion processing of N. oculata at 90 °C provided the best outcome for digestible protein, and yielded an excellent source of digestible protein, amino acids, and long chain omega-3 profile for rainbow trout and which could be an alternative to replace fishmeal in rainbow trout diets.
  • Keywords:
  • Source:
    Algal Research, 75, 103295
  • DOI:
  • ISSN:
    2211-9264
  • Format:
    PDF
  • Publisher:
    Elsevier BV
  • Document Type:
    Journal Article
  • Funding:
    Grant no. NA18OAR4170073
  • License:
  • Rights Information:
    CC BY
  • Compliance:
    Library
  • Main Document Checksum:
    urn:sha256:c3de2fadb409450f2a97978e17314e8898d901d119bdd2772a207c53aa8584dc
  • Download URL:
  • File Type:
    Filetype[PDF - 933.98 KB ]
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