Process effects on carinata Brassica carinata and camelina Camelina sativa seed meal compositions and diet palatability in Rainbow Trout Oncorhynchus mykiss

Abstract

Inclusion levels of raw carinata Brassica carinata and camelina Camelina sativa seed meals in animal diets, especially monogastrics, is limited by antinutrients, mainly glucosinolates (GLS), sinapine and crude fiber. The effect of processing on these seed meals composition was assessed by first subjecting cold-pressed (CP) carinata and camelina seed meals to extrusion (EX), solvent extraction (SE) and aerobic conversion (AC), or sequential process combinations to determine which process(es) yielded improved chemical composition. The palatability of the processed meals was then conducted to determine the effects of processing on meal acceptability in fish. Carinata meals generally yielded more crude protein than camelina meals for a given process treatment. Similarly, the fiber contents of carinata meals were generally lower than observed for camelina meals. Largest protein increase was due to oil removal and AC, but not EX. Generally, AC increased the essential amino acids (EAA) of all meals. Although AC increased the crude fiber of all meals, it reduced the GLS of all meals by at least 70 %, with more reduction observed in camelina meals. Palatability of carinata and camelina meals was improved by SE. Extrusion improved the palatability of camelina and AC improved the palatability of carinata. Generally, AC meals were higher in protein and EAA, lower in soluble carbohydrate and GLS than unconverted meals and would be suitable for use in fish diets. Extrusion did not improve the composition or palatability of CPEXSEAC beyond CPSEAC. Generally, CPSEAC carinata would be preferred by feed manufacturers over CPSEAC camelina because of a better EAA profile, higher protein content and lower crude fiber. Reduction of crude fiber in CPSEAC carinata would likely improve the utilization of nutrients, increasing meal utilization in fish and /or monogastrics in general. Digestibility studies should be conducted to improve an understanding of the utilization of the different processed carinata and camelina meals in fish and/ or monogastrics, in addition to processing economics.