Recycling biofloc waste as novel protein source for crayfish with special reference to crayfish nutritional standards and growth trajectory

Sci Rep. 2020 Nov 11;10(1):19607. doi: 10.1038/s41598-020-76692-0.

Abstract

Screening of novel feedstuffs, that too for data-deficient (nutritionally) animals, is somewhat ambiguous or problematic. Through systematic meta-analyses, the present study formulated most up-to-date crayfish nutritional standards, against which a recyclable waste (biofloc biomass, BM) from intensive aquaculture systems was assessed as a novel protein source. Growth trajectory dependencies and thermal growth coefficient qualifying for good growth in crayfish (TGC 0.5-0.64 units) were benchmarked. Using these standards and a 7-week growth trial, BM's suitability as a novel protein source for red swamp crayfish Procambarus clarkii was evaluated through its graded inclusions in a commercial feed. Results suggest that BM can elevate growth at 33-66% inclusion in existing feed formulations. Beyond 66% inclusion, BM can deteriorate growth in crayfish due to high ash content (exceeding physiological limit > 14%), arginine deficiency (~ 14-20% lower than an optimum requirement), and insufficient non-protein energy: protein ratio (3.7 cal mg-1). Arginine is perhaps the most critical amino acid in dietary protein for crayfish, and deficient in BM. Although no critical bioaccumulation levels of heavy metals were breached by feeding 100% BM to crayfish, a mineral and heavy metal (Hg) stress seemed plausible. Crayfish raised solely on biofloc may not realize full growth potential.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed*
  • Animal Nutritional Physiological Phenomena
  • Animals
  • Aquaculture / methods*
  • Astacoidea / chemistry
  • Astacoidea / growth & development*
  • Astacoidea / physiology
  • Cichlids
  • Fresh Water
  • Hepatopancreas / chemistry
  • Metals, Heavy / analysis
  • Proteins / chemistry
  • Proteins / pharmacology
  • Recycling*
  • Stress, Physiological
  • Waste Products

Substances

  • Metals, Heavy
  • Proteins
  • Waste Products