Effects of carbohydrate addition methods on Pacific white shrimp (Litopenaeus vannamei)

The addition of external carbohydrate in Pacific white shrimp (Litopenaeus vannamei) culture has shown positive effects on water quality and shrimp performance. However, this practice requires additional skills and labor, and therefore may not be widely adopted. This research investigated the potential to combine the carbon source and the feed in one pellet in shrimp culture. The carbon source used in this experiment was corn starch. The experiment was executed in 6 indoors mesocosms tanks, with full control of the water source, temperature, and light intensity and duration. The three treatments including COM-Feed (commercial feed), COM-Feed + CHO (commercial feed with separate corn starch addition), and CHO-Feed (pelleted diet made by incorporating additional corn starch into the commercial feed) were randomly assigned to the mesocosms tanks, and run two times consecutively. Adding corn starch separately resulted in higher shrimp biomass gain and protein efficiency ratio (P < 0.05), compared to dietary corn starch addition and no corn starch addition. Carbohydrate addition caused a significant drop in inorganic nitrogen and orthophosphate concentrations in the water. The treatments had no effect on the biofloc and periphyton growth, and the proximate composition of shrimp, biofloc, and periphyton, however increased the eukaryotic microbial diversity in the bioflocs. Meanwhile, the carbohydrate addition reduced the dietary energy and carbon utilization efficiencies regardless of the carbohydrate addition methods.