A comparative analysis of muscles nutrient composition between cultured male and female black-spotted frogs ( Pelophylax nigromaculatus )

This study compared growth traits and hind‑limb muscle nutritional composition between male and female cultured black‑spotted frogs ( Pelophylax nigromaculatus ) to evaluate the influence of sex on production performance and product nutritional value. A total of 141 adult frogs (77 males, 64 females) were weighed at a farm in Changde, Hunan, and ~7 males and ~7 females were randomly selected for carcass and hind‑limb weight measurement and muscle sampling. Three muscle samples per sex were analyzed for proximate composition, amino acid profile, and fatty acid composition; essential amino acid index (EAAI), amino acid score (AAS), and chemical score (CS) were calculated according to FAO/WHO and reference protein models. Female frogs had significantly greater body weight, carcass weight and hind‑limb muscle mass than male frogs ( P < 0.05). No significant sex differences were found in basic proximate components (moisture, crude fat, ash). Amino‑acid analysis indicated that males generally had higher amino‑acid contents, with several amino acids (alanine, histidine, arginine, isoleucine, leucine, valine, etc.) significantly higher in males than in females ( P < 0.05). Despite these individual amino‑acid differences, composite protein‑quality indices (EAAI, AAS, CS) showed no clear differences between sexes; fatty‑acid profiles also revealed no adverse or significant sex‑related differences. Overall, sex had a significant effect on yield in black‑spotted frogs but a limited effect on overall muscle nutritional composition. Except for certain amino acids, the nutritional value of meat from both sexes was similar; therefore, sex can be considered as a factor to improve yield and economic efficiency in breeding and farming practices.