Assessment of Plant- and Microbial-Derived Protein Hydrolysates as Sustainable for Fetal Bovine Serum in Seafood Cell Culture Media

• Reducing serum without providing a serum replacement will significantly reduce cell number and cell viability. • Low concentrations of protein hydrolysates (0.01 mg/mL), in combination with low concentrations of serum (1 and 2.5%), will improve cell growth, viability, and sustainability of the cultivated seafood media. • Providing protein hydrolysates for media with a high amount of serum will significantly reduce cell growth and cell viability. This study seeks to explore alternatives by substituting or reducing the conventional 10% serum concentration in zebrafish embryonic stem cell (ESC) growth media with protein hydrolysates sourced from peas, mushrooms, yeast, and algae. Notably, algae exhibited the highest protein content, optimal amino acid balance, and favorable functional properties. When applied at concentrations ranging from 1 to 10 mg/mL, all protein hydrolysates demonstrated pro-apoptotic effects and inhibited cell growth, particularly when used in conjunction with 10% serum. However, concentrations ranging from 0.001 to 0.1 mg/mL displayed anti-apoptotic properties and promoted cell proliferation. The study found that media containing 1% or 2.5% serum, along with 0.01 mg/mL of protein hydrolysates, supported cell growth effectively. Lactate Dehydrogenase (LDH) Activity served as an indicator of cell health and integrity under the specified conditions of protein hydrolysate supplementation. Cells cultured in serum-free media exhibited significantly decreased cell membrane integrity ( P < 0.05 ) compared to those in regular media or media containing low serum (1% and 2.5%) along with low concentrations (0.01 mg/mL) of protein hydrolysates. Furthermore, analysis of Greenhouse Gas emissions (GHG) suggested that media formulations containing 1% serum combined with low concentrations of protein hydrolysates present a sustainable approach for cell-based seafood production.