Pacific white shrimp Litopenaeus vannamei are raised in low salinity waters in west Alabama. Therefore, m ethods to improve growth and immune response to improve production and profitability are of interest to commercial producers. These studies examined the use of a protease (AG-175) in two different protein diets for shrimp. The first study evaluated three diets including a 32% crude protein diet with AG-175 added to the mixture and extruded, a 32 % top coated onto extruded feed, and a 32% protein feed in which no AG-175 added. This 6-week study was carried out by stocking 20 shrimp , mean initial weight 0. 366 g + 0.001 , in an on-levee tank system with 12 800-L tanks installed adjacent to a shrimp production pond on a commercial farm in west Alabama. The shrimp were offered three different 32% protein feeds and all treatments were quadruplicated. The second study used the identical 32% diets and 28% diets with AG-175 incorporated as mentioned for the 32% (6 diets, 4 replicates). All diets were evaluated regarding shrimp growth, feed conversion, and immunological parameters. These parameters included cell counts, enzymatic activity, and protein content in Pacific white shrimp. In this study fifteen shrimp were stocked, mean initial weight 0.10 g + 0.0006, into 24 75-L aquaria that were part of a recirculation system consisting of a sand filter, biofilter, and sump (3900 L total system volume) at the Alabama Fish Farming Center. This study lasted six weeks. No significant differences in growth, FCR (Figure 1A,B) , or survival occurred for any of the diets tested in these studies. Immunological parameters are being analyzed and will be reported. Based on these preliminary findings, AG-175 does not appear to improve shrimp production in low salinity waters.