Amino acid composition of muscle proteins of diploid and triploid tench (Tinca tinca, Linnaeus 1758)

Abstract

The aim of the study was to determine the differences in the composition of amino acids (in % of total determined amino acids) between diploid (2n) and triploid (3n) tench of identical genetic specifications and raised under the same conditions, in relation to sex (F-female vs. M-male) and age (T 3-36 months vs. T3+- 42 months). A total of 38 mixed samples of muscle tissue from 137 tench divided by sex, ploidy and age were analyzed. The effect of ploidy and sex on the composition of the spectrum of amino acids of muscle proteins was greater in the T3 tench population. The following differences in values were found: female fish (ploidy effect): Thr (p < 0.05), Arg (p < 0.05), Pro (p < 0.01) Gly (p < 0.01); male fish (ploidy effect): Ile (p < 0.01); diploids (sex effect): Arg (p < 0.05); triploids (sex effect): Pro (p < 0.01). In the T3+ tench population, highly significant (p < 0.01) differences in Gly contents in female fish (ploidy effect) and triploids (sex effect) were found. Lower levels of the following amino acids were found in muscle tissue of T 3+ tench compared with the T3 (younger) tench population: Val, Phe, Lys, His, Arg (in F 2n and M 3n), Pro (in F 3n) and Tyr. Levels of Thr, Ile, Leu, Arg (in M 2n and F 3n), Asp, Glu, Gly and Ala, on the other hand, were higher in T3+ tench. Results of the present study suggest that the qualitative and quantitative compositions of some amino acids bound in tench muscle proteins may be statistically significantly influenced by such biotic factors like sex, ploidy and age.