Striped bass (SB, Morone saxatilis) are an important aquaculture fish as a parental species of hybrid striped bass, the fourth largest finfish aquaculture industry in the US. The predominant hybrid produced in this industry is a cross of white bass (M. chrysops ) females and SB males known as the “reciprocal” cross. However, d ecades of domestication through the National Program for Genetic Improvement and Selective Breeding for the Hybrid Striped Bass Industry have led to substantial improvements in the captive breeding of SB, such as spawning without exogenous hormone compounds, thus facilitating a standalone SB industry to emerge .
The consistent production of high-quality eggs to support a reliable supply of seedstock is critical and often a major bottleneck in expanding finfish production, as has historically been the case with SB . Previous research on gene expression profiles of the SB ovarian transcriptome identified a transcriptomic signature highly predictive of egg quality. To expand upon these findings and identify the proteomic components underlying egg quality in these fish , tandem mass spectrometry (nano-LC-MS/MS) and a novel ensemble machine learning approach was used to profile the proteome of p reovulatory oocytes (PV, post-vitellogenic, obtained prior to the natural spawning season begin in April) and ovulated eggs (OV, obtained after final ovarian maturation) collected from four-year-old domestic female SB (N=16, mean + standard deviation weight: 3.35 + 0.11 kg , total length: 583.6 + 7.1 mm) . The PV and OV represented high- and low-quality spawns, whereby spawns resulting in > 50.0 % of eggs producing viable 4-hour embryos (n=8 of 16 spawns) were designated as high- quality and spawns resulting in < 30.0 % of eggs producing viable 4-hour embryos (n=8 of 16 spawns) low-quality. The resulting proteomic profiles suggest direct and complex linkages between cytoskeleton structure and protein biosynthesis/degradation processes (ribosome , ubiquitin-26S proteasome) as being major differentiating factors between PV and OV quality and stage. These findings complement the previously modeled transcriptome profiles and collectively highlight pathways of importance during early development in high quality PV and OV and provide greater insight into cellular dysfunction occurring in low quality PV and OV. These findings can be considered in the design of future research to determine the parental factors (e.g., genetic, dietary, husbandry) underlying the discrepancy between females producing high- and low-quality spawns and subsequently the breeding strategy for domestic SB.