By : ANDREW J. RAY, PH.D.School of Aquaculture, Kentucky State University Land Grant Program, 103 Athletic Road, Frankfort, KY 40601 USA
JOHN W. LEFFLER, PH.D.South Carolina Department of Natural Resources Marine Resources Research Institute, 217 Fort Johnson Road, Charleston, SC 29412 USA.
CRAIG L. BROWDY, PH.D.Director of Research & Development Zeigler Bros., Inc. 400 Gardners Station Road, Gardners, PA 17324 USA
The results of this study show that changes in diet and biofloc management clearly have implications for the nutritional and sensory qualities of shrimp, offering unique opportunities to modify the characteristics of shrimp that are important to consumers.
Biofloc-based aquaculture systems use very little water exchange and shrimp are planted at high densities. When stocking densities are high, intensive nutrient inputs are used and in response a dense microbial community develops in the water column. This microbial community includes bacteria, algae, fungi, zooplankton and protozoa, which function to cycle the nutrients in the system, i.e. ammonia, and can also serve as a supplementary food source for animals such as shrimp.
There appears to be little research on how changes in the microbiota can affect the nutritional quality of the bioflock, and there are almost no studies exploring how microbial changes can affect the human nutritional and sensory profiles of shrimp in bioflock systems. Previous research has shown that shrimp can perform well in diets containing little or no fish products.
Removing fish products from the diets of aquaculture species can significantly improve environmental sustainability, reduce feed price fluctuations and improve marketing opportunities for farmed shrimp. However, it is not clear what implications the use of fish-free diets may have on the microbial community of the biofloc, as well as on the nutritional and sensory values of shrimp for humans, as the composition of plant-based products is significantly different from that of fish products.
Some studies have been conducted on the effects that diet composition may have on the microbial community in biofloc systems; however, the effects on nutritional or sensory parameters of shrimp and any potential interactions between microbial composition and product quality appear to be relatively poorly understood. It is not clear how an important food component, such as a protein source, can affect the human sensory characteristics of shrimp, particularly in biofloc systems where the microbial community may also play a role in product quality.
Human sensory analysis of shrimp – such as taste, texture, appearance and flavour attributes – can help determine product quality. This is particularly important when exploring new production systems or management styles and the use of new diets to ensure consistent product quality.
As the industry moves towards more intensive production systems where the microbial community plays a greater role in system performance, and moves towards the use of less fishmeal, or even fish-free diets, it is important to explore the implications for system and feed management. Product quality and the role that the microbial community can play in this regard.