Inclusion of ingredients rich in non-starch polysaccharides (NSP) in pelleted feed can serve as a carbon-rich source to manage water quality and production of Pacific white shrimp ( Litopenaeus vannamei ) in biofloc systems. However, the inclusion, source and type of NSP (i.e. fermentability) can affect the feed quality by reducing the dietary protein content and nutrient utilization. This study evaluated the effects of replacing dietary starch in a commercial-like diet (STdiet), with either poorly fermentable (PF) or moderately fermentable (MF) NSP-rich ingredients. Moreover, two feeding approaches were tested to counteract with the lower protein content of the NSP-rich diets: feeding either iso‑nitrogenously (IN) or at as-is basis (IB), resulting in five dietary treatments: IN-PF, IN-MF, IB-PF, IB-MF and STdiet. Digestibility (30-day trial) and growth performance (42-day trial) were assessed, as well as the biofloc nutritional and microbial composition. Pacific white shrimp had a lower nutrient digestibility when fed NSP diets compared to the STdiet. The NSP type did not affect shrimp performance, biofloc formation and water quality. Feeding iso‑nitrogenously compared to as-is basis resulted in similar performance between treatments and increased the protein content in both shrimp and biofloc. With regard to the biofloc microbiota composition, inclusion of NSP-rich ingredients in the diets moderated the prokaryotic community by decreasing Cyanobacteria and increasing Actinobacteria abundance. In conclusion, when fed iso‑nitrogenously, the type of NSP-rich ingredients did not affect biofloc system performance and worked as effectively as the STdiet in maintaining water quality. • NSP-rich diets eliminate the necessity of carbon addition in biofloc systems. • NSP types does not affect the shrimp or biofloc production. • Protein level is important when formulating NSP-based system feed. • NSP diets alter the prokaryotic composition of biofloc. • NSP diets maintains water quality as well as starch diets.
Vinasyiam et al. (Sun,) studied this question.