PERFORMANCE OF SELECTIVELY BRED PACIFIC WHITE SHRIMP (Litopenaeus vannamei) FED LOW PROTEIN AND VEGETABLE PROTEIN DIETS

This study examines the effects of two experimental diets on the growth and survival of Pacific white shrimp Litopenaeus vannamei that either were selected for growth on high protein diets or were unselected control shrimp. Shrimp were stocked in 48 1.5-m3 tanks at 100 shrimp per tank (66 shrimp/m3) for 8 weeks with no water exchange. In the first experiment, a 25%-protein diet was compared to a 35%-protein diet with fish meal as the largest source of protein in both diets. In the second experiment, the same 35%-protein diet was compared with a 35% vegetable protein diet with all the protein originating from terrestrial plant crops. Shrimp were fed 8 times per day at 5 to 8% body weight per day. Weight at stocking for select and control shrimp was 2.9g and 2.8g, respectively. Shrimp selected for growth grew better than control shrimp on all diets (P<0.05). Survival ranged from 73 to 81% and there was no significant difference in survival between select or control shrimp or between diets (P>0.05). Shrimp grew significantly faster when fed the 35% protein diet compared to the 25%-protein diet and shrimp grew significantly faster when fed marine protein versus vegetable protein (P<0.05). Heritability for growth was high in all diets with half-sib heritability (+SE) of 0.50+0.22 for the 35%-protein diet, 0.72 + 0.41 for the 25%-protein diet, and 0.40+0.30 for the vegetable protein diet. Shrimp selected for growth grew 28 and 32% faster than control shrimp when fed the 35%-protein and 25%-protein diet in experiment 1, respectively. Select shrimp grew 13 and 9% faster than controls when fed the marine and vegetable protein diets, respectively, in experiment 2. Select shrimp grew better than controls in all the diets despite being selected for growth on diets with protein levels greater than 30%. In addition, there was no interaction between families and diets (P>0.05) indicating that the fastest growing families grew the fastest on all the diets. Consequently, it is currently not necessary to breed lines of shrimp for each of these specific diets.