Aquaculture America 2024

February 18 - 21, 2024

San Antonio, Texas

EVALUATION OF VARIOUS CONCENTRATIONS OF A PROTEASE COMPLEX FEED ADDITIVE IN LOW-SALINITY CULTURE OF Litopenaeus vannamei

James T. Tuttle*, Timothy J. Bruce, Luke A. Roy, Hisham A. Abdelrahman, Julio C. García, Benjamin H. Beck, and Anita M. Kelly.

 

Alabama Fish Farming Center of  Auburn University,

 Greensboro, AL 36744

jtt0039@auburn.edu

 



 Protease feed additives have been proven to improve digestibility and obtain improved growth while using less protein in aquatic feeds. Some of these protease complexes have been shown to have immunostimulant effects that  significantly improve growth performance ,  survivability,  and  disease resistance  in many commercially  important aquaculture species . However, with  the variety of available immunostimulants,  differing  feed preparation  methods, and  diversity of finfish and invertebrate species grown commercially, there is still the potential  to optimize  which concentrations of  proteases would yield the most efficient, biologically beneficial, and cost- effective growth.  One of the most economically important  and versatile  aquaculture species is  the Whiteleg s hrimp Litopenaeus vannamei ,  known to  tolerate salinities between 0.5 and 4 0 .

To evaluate growth, phy siological, and immunological parameters of  L. vannamei fed a diet containing differing amounts of a protease  complex under low-salinity culture conditions,  360 shrimp ( mean ± SD = 0.35 ± 0.03 g ) were stocked  equally into  a low-salinity recirculating system  consisting of 24, 67- L tanks. Four treatment diets were formulated, each containing 35% protein, 8% lipid ,  and  27% carbohydrates.  Three of the four treatment diets contained 131, 175, and 208 mg/kg of Jefo’s AG-175 protease complex . Each treatment diet was fed to shrimp in six replicate tanks , four times daily, for six weeks. Final biomass, final individual weights , feed conversion ratios (FCR) ,  and weight gains were compared. Physiol ogical parameters including hemolymph osmolality, hemolymph ion concentrations, whole body proximate analysis, and intestinal histology were evaluated . Immunological parameters such as hepatopancreas gene expression and intestinal microbiota were analyzed.  There were no differences in final individual weight (P = 0.0975) or weight gain (P = 0.2849) between treatments. There were differences in FCR (figure 1) between treatments . P hysiological and immunological results will be presented. The findings of this comprehensive study will  determine  which concentration of the AG-175 protease will yield the

 most effective growth in low-salinity  L. vannamei culture.