Assessment of the use of cooked Araucaria angustifolia seed coats extract as food for brine shrimp.

The use of vegetable waste and its screening for potential cytotoxicity is of utmost importance to ensure its safe use in the feed industry for fish and other animals. We evaluated aqueous and ethanolic extracts of cooked Araucaria angustifolia seed coats. The Stiasny index for the aqueous and ethanolic extracts was 2.87% ± 0.03% and 60.53% ± 4.79%, respectively. Condensed tannins were 11-fold higher in the ethanolic extract than the aqueous extract. The flavonoid and polyphenol contents were 1.7- and 1.8-fold higher in the ethanolic extract than in the aqueous extract, respectively. The 36 h EC ₅₀ for brine shrimp hatchability was 300.32 µg/mL for the aqueous extract, and 76.60 µg/mL for the ethanolic extract. The 24 h LC ₅₀ was 1405.96 µg/mL for the aqueous extract, and it was 356.32 µg/mL for the ethanolic extract. The aqueous extract was nontoxic to A. salina nauplii, and therefore, it can be used as a possible food additive in fish feed. The results also demonstrated that the different solvents used in the extraction affected the yield and the total phenolic, total flavonoid, and condensed tannin content. Further in vivo and cell line cytotoxicity testing is recommended to substantiate these findings.