Physical-chemical characteristics of “Red Meal”, a novel non-defatted additive in the fish feed from cracked biomass of Haematococcus pluvialis

Abstract

Haematococcus pluvialis (HP) astaxanthin is widely used in the aquaculture industry to improve the pigmentation of salmon, shrimp, and egg yolk, also this pigment has an important physiological role in animal health and reproduction. The “Red Meal” (RM) is the whole cracked biomass of HP homogenized in vegetable oil to form a non-defatted meal product. This study aimed to determine the physical and chemical characterization of a novel non-defatted meal feed product (“Red Meal”, so-called by the production company). RM behavior was shear-thickening fluid at 40 °C, whereas, at 5, 10, 25, 30, and 60 °C shear-thinning fluid was observed; thus, viscosity was decreased with the increase of shear rate. On the other hand, the RM presented a 14.5 ± 0.1, 62.5 ± 9.6, 17.6 ± 2.7, 3.7 ± 0.1, and 1.5 ± 0.4% of protein, lipids, carbohydrates, ash, and moisture, respectively. The fatty acid profile of RM was 51.1% of linoleic acid C18:2(c9c12), 25.4% of oleic acid C18:1(c9), 9.5% of palmitic acid C16:0, 7.9% of heneicosylic acid C21:1%, and 2.8% of stearic acid C18:0, where the linoleic acid and oleic acid represented 76.5% of the total fatty acid profile. Additionally, the most abundant polyunsaturated fatty acid was ω-6 (51.40%), followed by ω-9 (25.40%); whereas a small amount of omega-3 (0.88%) was reported. The total carotenoid content in the RM was 17.19 mg/g of dry biomass; in which the main pigment was astaxanthin esters (55.13%), followed by lutein (5.67%), free astaxanthin (5.54%), β-carotene (2.76%), and canthaxanthin (2.65%).