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

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.

Understanding Nutrition and Metabolism of Threatened, Data-Poor Rheophilic Fishes in Context of Riverine Stocking Success- Barbel as a Model for Major European Drainages?

“…Among native rheophilic cyprinids considered, species with statistically similar ( p > 0.05) body composition were assumed and classified to be similar in terms of nutritional requirements. The tests were performed using RStudio v1.2.5042 using libraries ‘e1071’, ‘dunn.test’ and ‘FSA’ [ 27 , 28 ].…”

Biofloc technology as part of a sustainable aquaculture system: A review on the status and innovations for its expansion

“…Similar results were achieved in the dietary inclusion of 15.6% biofloc meal and the 7.8% biofloc meal with FO inclusion experiments, indicating that this approach was reproducible (Kuhn et al., 2009). An additional study carried out on red swamp crayfish ( Procambarus clarkii ) suggested that biofloc meal supplied alongside existing feed at a rate of 33%–66% inclusion can elevate growth rate; however, beyond 66% inclusion reduces growth rate owing to the increased ash content which eventually exceeds the species limit at 14% (Lunda et al., 2020).…”

“…An additional study carried out on red swamp crayfish (Procambarus clarkii) suggested that biofloc meal supplied alongside existing feed at a rate of 33%-66% inclusion can elevate growth rate; however, beyond 66% inclusion reduces growth rate owing to the increased ash content which eventually exceeds the species limit at 14% (Lunda et al, 2020).…”

Biological insights into the rapid tissue regeneration of freshwater crayfish and crustaceans

“…In contrast, the Arthropoda phyla (subphylum crustacea and class insecta) possess limited regenerative ability, although they provide insights into conserved regenerative mechanisms and systems 5,6 . Freshwater crayfish (Crustacea, Decapoda, Astacida) are a diverse taxonomic group, endemic to the continents of North America, Australia‐Oceania and Europe 7 . They can regenerate various anatomical structures, such as chelipeds, pereiopods, uropods, antennae, brain neurons and the compound eye 8,9 .…”