Evaluation of Filamentous Fungal Biomass Cultivated on Vinasse as an Alternative Nutrient Source of Fish Feed: Protein, Lipid, and Mineral Composition

Sajjad Karimi,Nasrollah Mahboobi Soofiani,Mohammad J Taherzadeh,Anders Kiessling,Amir Mahboubi,Torbjörn Lundh

doi:10.3390/fermentation5040099

Sajjad Karimi, Nasrollah Mahboobi Soofiani + Show 4 more

Open Access

https://doi.org/10.3390/fermentation5040099

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Abstract

The rapid growth of aquaculture and scarcity of conventional fish feed supplements has prompted the introduction of new sustainable supplementation sources. In this study, the potential of five strains of fungal biomass of Ascomycetes and Zygomycetes edible filamentous fungi, Aspergillus oryzae, Neurospora intermedia, Rizhopus oryzae, Monascus purpureus, and Fusarium venenatum, cultivated on vinasse, a by-product of the bioethanol industry, as alternative protein sources for fishmeal in the fish diet was evaluated. It was observed that 5% vinasse with an initial pH of 5–6.5 can support fungal biomass yields of 34.3 ± 2.4–118.5 ± 3.9 g DM/L for A. Oryzae, N. intermedia, and R. oryzae. High protein contents of about 44.7%, 57.6%, and 50.9% (w/w), and fat contents of 7.0%, 3.5%, and 5.5% (w/w) were obtained for A. oryzae, N. intermedia, and R. oryzae, respectively. The latter three fungi species contained noticeable amino acid contents, including promising profiles of amino acids that are highly compatible with those of fishmeal. These findings provide evidence that fungal biomasses, with their relatively high protein content, good amino acid profiles, and other essential nutrients, are a promising supplementation alternative that can be produced from low-value by-products and organic-rich waste streams like vinasse to meet the dietary protein requirements in fish feed.

Highlights

IntroductionAccording to the Food and Agriculture Organization [1] annual report, fish production has increased by 7.1% throughout aquaculture in the last decade, while wild fish capture fisheries have been stagnant since 1980, followed by a decreasing trend since 2011 [1]
Aquaculture has expanded rapidly during the last two decades
In order to investigate the potential of vinasse in the production of a fungal biomass that could further be applied in fish feed supplementation, five different strains of edible filamentous fungi were cultivated on vinasse

Summary

Introduction

According to the Food and Agriculture Organization [1] annual report, fish production has increased by 7.1% throughout aquaculture in the last decade, while wild fish capture fisheries have been stagnant since 1980, followed by a decreasing trend since 2011 [1]. Of the total of 170.9 million tons of fish produced (including both captured and farmed), 80.0 million tons (46.8%) is provided by aquaculture. Under intensive fish culture systems, fish production is significantly dependent on artificial feed supplementation [1]. Fishmeal is the major ingredient of feed supplements that meet the protein requirements of the fish diet [2]. Fishmeal production is strongly dependent on the capture of wild fish. It is expected that 16% of the total fish captured from the natural resources will be used to produce fishmeal by 2030.

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