012: Optimizing Low-Serum Growth Media for Mackerel Fish Cells

Introduction

Cell-cultivated fish holds promise as a sustainable and ethical seafood alternative. Current reliance on fetal bovine serum (FBS) in cell growth media hampers scalability due to its high cost and ethical concerns. The development of low-serum or serum-free media for fish cell culture remains understudied. This study presents a cost-effective, low-serum media optimized for the Mack1 Atlantic mackerel (Scomber scombrus) muscle cell line (Saad et al., 2023), enabling robust proliferation and advancing the development of scalable cell-cultivated fish.

Methods

As previously described in literature, a low-serum (2.5% FBS) growth media, termed “BBB,” was developed for Mack1 cells (Lim et al., 2024). RNA sequencing of Mack1 cells identified 22 upregulated receptors in proliferation. Ligands to those receptors were individually screened in 2.5% FBS growth media “BBB” and optimized using design of experiments. To evaluate new media formulations for cell growth, cells were cultured in 96-well plates. After 5 days of culture, cell number was quantified with Hoechst-33342 nuclei staining and imaging with the Celigo image cytometer (Revvity).

Results

Screening in 2.5% FBS growth media identified chemerin, apelin, and gremlin as the top ligands for promoting cell proliferation. Using design of experiments and further reducing FBS to 1%, the optimal combination—50 ng/mL apelin, 150 ng/mL gremlin, and 120 ng/mL chemerin—achieved the highest short-term proliferation.

Significance

This study successfully developed a serum-reduced growth media for Mack1 cells that uses only 1% FBS while achieving cell proliferation equivalent to media containing 7.5% FBS. This breakthrough addresses the ethical and economic challenges posed by FBS, a component derived from calf blood and widely used in the biotechnology industry despite its conflict with the goals of cultivated meat. By reducing FBS dependency, the optimized media aligns with the fundamental objectives of cultivated meat: improving animal welfare and promoting sustainability. These findings mark a significant step toward scalable and ethical production of cell-cultivated seafood, advancing the development of sustainable food systems.

Authors: Julia Sun, Calliope Foo, Michael K. Saad, David L. Kaplan