Muscle Characteristics and Transcriptomic Analysis of Diploid and Triploid Tiger Pufferfish (Takifugu rubripes)

Sexual maturity in tiger pufferfish (Takifugu rubripes) consumes substantial metabolic energy, constraining somatic growth and limiting meat yield. Artificial triploid induction (sterility) may redirect energy toward somatic growth. Cold-shock induced triploids were compared with diploid controls using muscle and liver tissues, and the phenotype, histology, nutritional composition, hormone levels, as well as transcriptome profiles were assessed. After 5 months, triploids attained significantly greater body length and body weight, with larger muscle fiber diameter but lower fiber density. The triploids yielded lower ash content and higher amounts of total (TAA), essential (EAA), non-essential (NEAA), and delicious amino acids (DAA), as well as higher total fatty acids (TFA), total polyunsaturated fatty acids (PUFA), and omega 3 polyunsaturated fatty acids (n-3 PUFA). Growth-related hormones were elevated, including growth hormone (GH), testosterone (T), triiodothyronine (T₃), and thyroxine (T₄). Muscle transcriptome sequencing identified 231 differentially expressed genes, predominantly enriched in pathways related to cell growth regulation, metabolic processes, and energy conversion. These results provide reference data for breeding programs.