World Aquaculture Singapore 2022

November 29 - December 2, 2022



William W. Riley* and Orapint Jintasataporn

Botaneco ®, Inc., Calgary, Alberta, Canada


Canola protein concentrate (CPC: 78.9% crude protein (CP)) was added to isocaloric, isonitrogenous White Leg shrimp (Litopenaeus vannamei) diets as a replacement for 65% CP fishmeal at 0, 5, 10 or 20% inclusion in the final formulation. Juvenile shrimp (~2 gm) were stocked at 80 shrimp/m3 (25 shrimp/tank) and fed 3 times daily at 3-4% bodyweight for 8 weeks. The study was carried out in 24 aquarium (4 treatments*6 replicates), each with 240 L capacity and containing 150 L of 10-15 ppt saline water, pH 7.7-8.2, DO>5 ppm, temperature 27-30o C, total ammonia <1.0 ppm. Aquarium water was batch-exchanged 15-20% every 2 days. At 8 weeks, the growth of shrimp fed 5-20% CPC was higher (p<0.05) than the growth of control shrimp fed 0% CPC. At 6 and 8 weeks, weight gain and specific growth rate were higher (p<0.05) at 10% and 20% CPC than at 0% CPC, while shrimp fed 5% CPC did not differ from the control group. Feed intake did not differ (p>0.05) between treatments, but the feed conversion ratios (FCRs) were lower (p<0.05) in 5-20% CPC-fed shrimp than in control shrimp at 2, 4, and 6 weeks. At 8 weeks, the FCRs were equivalent (p>0.05), as were survival rates (p>0.05). CPC was highly digestible: dry matter=74.10+3.55%, protein=86.00+2.70%, lipid=95.58+0.24%, calcium=40.55+15.05%, phosphorus=95.82+1.88%, energy=78.97+2.29%. The haemocyte count and hemolymph protein did not differ between treatments (p>0.05), whereas phenoloxidase activity was higher in shrimp fed 5-20% CPC (p<0.05) relative to the control. The moisture, dry matter, ash, calcium, phosphorus, lipid, and fiber contents of shrimp for all treatments were similar (p>0.05), while the protein content of shrimp fed 10% and 20% CPC was higher (p<0.05) than the protein content of the control shrimp. After 8 weeks, 10 shrimp from 3 replicates/treatment were moved to 100 L challenge test aquaria. Shrimp were subcutaneously injected with Vibrio parahaemolyticus (EMS) at 0.1 ml/shrimp. Shrimp survival during 7 days of infection did not differ among the 4 treatments from days 0 to 6 (p>0.05), but at day 7, the shrimp fed 20% CPC had a higher survival rate (p<0.05) than did shrimp fed 0% and 5% CPC. Hemocyte counts, hemolymph protein, and phenoloxidase activity  were  the same (p<0.05) as were the vibrio counts in the hemolymph (p<0.05). However, vibrio counts in the hepatopancreas and intestine were lower in shrimp fed 5-20% CPC (p<0.05) compared to control shrimp. CPC promoted a reduction in hepatopancreatic and intestinal vibrio counts under conditions of vibriosis due to improved health and immunity. CPC can replace fishmeal in the diet of Pacific White Leg shrimp (Litopenaeus vannamei) at inclusion rates from 5-20%. CPC has high protein and lipid digestibility, and it was shown to promote growth performance, immunity and disease resistance against Vibrio parahaemolyticus EMS at an inclusion rate as high as 20%.