Biofloc technology (BFT) has emerged as a sustainable method for prawn cultivation, particularly for regions with limited freshwater resources. The freshwater prawn Cryphiops caementarius exhibit improved survival and growth rates when cultivated using BFT compared to traditional clear water (CW) systems. Despite the impor­ tance of bacterial microbiota in organismal health and performance, our study represents the first comprehensive investigation into the impact of BFT and CW culture systems on the composition, dynamics, stability, and functional potential of bacterial communities in both the rearing environment and intestines of C. caementarius . Utilizing deep amplicon 16S rRNA sequencing, we assessed the diversity and relative abundances of bacterial microbiota in CW and BFT water systems and in the intestines of prawns cultured in these systems over an extended period. Results revealed higher host-environment interaction in BFT, and higher bacterial diversity in BFT water systems and prawn intestines. The environment and prawn intestines from BFT were enriched with beneficial bacteria, while CW counterparts harbored potentially pathogenic bacteria. Planctomycetota was the dominant phylum in BFT, while Proteobacteria predominated in CW. Functional profiling indicated efficient support for chemoheterotrophic bacteria in both systems, with greater nitrogen processing in CW but greater nitrite detoxification in BFT system. Cellulolysis was higher in the intestines of prawns from BFT, potentially enhancing nutrient availability. Prawn intestine microbiota exhibited high plasticity post-immune challenge, with notable colonization by potentially pathogenic bacteria ( Aeromonas and Pseudomonas ) at the expense of a decrease in beneficial bacteria, in both systems. However, prawn intestines from BFT also showed high colo­ nization by beneficial bacteria such as Shewanella , with potential for improving immune response. Overall, our study sheds light on the complex interplay between water and intestinal microbiota in BFT and CW systems during C. caementarius cultivation, offering insights into the potential for harnessing beneficial microbiota to improve prawn health and performance, particularly through the BFT system

Reductions of its natural populations have led to recent efforts in small-scale aquaculture of the freshwater prawn Cryphiops caementarius, either for conservation or commercial purposes. However, the lack of knowledge about its nutritional requirements has been one of the major obstacles for its successful culture. Given its importance, this study determines and compares the chemical composition (moisture, ash, crude protein, total lipids and nitrogen free extract) of whole animals and main storage tissues (gonad, hepatopancreas and muscle), of C. caementarius adult prawns from two natural populations. Moreover, the relation of this composition with reproductive and environmental parameters (sex, maturation and habitat) is discussed. The specimens were collected in Limarí and Choapa rivers (Coquimbo, Chile) during reproductive season, and divided into six categories according to capture location, gonad maturation stage, and gender. The chemical composition of whole animals and storage tissues was compared among categories. Significant differences were observed between tissues, sexes, maturity stages and locations. Regarding tissues, the muscle and the gonads were rich in protein, whereas the hepatopancreas had high lipid content. According to results, factors such as sex, habitat and stage of gonad maturation can modify the biochemistry of C. caementarius. Nonetheless, the main chemical variations were observed in tissues involved in regulatory processes (hepatopancreas and gonads), and to a lesser extent in structural tissues (muscle). This is the first study known that reports information about the biochemistry of C. caementarius and its findings may be useful to improve feeding practices in aquaculture.

This study aimed to evaluate and compare the effects of biofloc technology (BFT) and clear water (CW) on water quality physiological and productive performance of juvenile freshwater Northern River shrimp, Cryphiops caementarius under three stocking densities (100, 200, and 400 shrimp m⁻²). Shrimp with an initial body weight of 0.44 ± 0.07 g were stocked in 18 rectangular fiberglass tanks with a water volume 150 L for 290 days. During the experiment, water quality parameters stayed within acceptable ranges for shrimp growth. The highest survival rate was recorded in BFT treatments; however, the growth performance of shrimp in the treatments with the lowest stocking density was higher than that with the highest stocking density, regardless of whether BFT or CW was used. Transcriptional levels of heat shock protein (Hsp70) and superoxide dismutase (SOD) showed significant differences (p < 0.05) between treatments, particularly in BFT. These results indicate that an initial stocking density of 200 shrimp m⁻² appears to be appropriate for shrimp juveniles cultured in a BFT system. Thus, this technology emerges as an effective tool for river shrimp farmers looking to increase their stocking densities and improve the efficiency of their production systems in arid zones.