Use of Genetically Modified Canola Oil as a Replacement for Fish Oil in Practical Diets for Whiteleg Shrimp Litopeneaus vannamei Reared in Green Water Conditions

Abstract

With current advancements in technology allowing for genetic modification of crops, canola has been modified to contain n3 long-chain polyunsaturated fatty acids such as docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). The purpose of this study was to determine the efficacy of using genetically modified canola oil as a DHA and EPA replacement for Menhaden fish oil (FO) in practical diets for Pacific white shrimp Litopeneaus vannamei. This trial was conducted using twenty-four 750 L tanks stocked at 40 shrimp per tank (0.1 ± 0.007 g initial weight) and grown for 63 days. Shrimp were fed one of five experimental diets (36% protein, 8% lipid) with supplemental FO replacement varying from 75% to 100% twice daily (7 a.m. and 7 p.m.). Two of the diets contained 15% fishmeal (FM) as the basal protein source, while the other three diets were FM free, allowing for complete removal of DHA sources in the basal formulation. While basal FO was removed, none of the experimental diets were completely devoid of FO. Shrimp were harvested and frozen after 9 weeks to be used for lipid extraction and taste and texture analysis by an untrained panel to mimic consumer responses. Results were subjected to a two-way analysis of variance, with significant differences observed in final mean weight (8.47–10.59 g) ( $p=0.0275$ ), individual weight gain (8.37–10.48 g) ( $p=0.0279$ ), and weekly gain (0.84–1.05 g) ( $p=0.0378$ ). Human sensory analysis did not yield significant differences between measured taste parameters ( $p>0.05$ ). Lipid extraction and analysis results showed that fatty acid concentrations from whole shrimp samples correlate with diet lipid profiles except for EPA. There is no significant difference ( $p>0.05$ ) in EPA concentrations in whole shrimp samples regardless of diet. These results suggest that Latitude™ oil can be successfully used as a partial replacement for FO in commercial shrimp diets.