Abstract
This study examined the growth characteristics, nucleotide sequence variations, and economic evaluation of two duck breeds. For this investigation, 150 each of 300 male Muscovy and Pekin ducklings aged one week were used. Body weight gain (BWG) as well as the initial and final live body weights were noted. Feed conversion ratios (FCR) and average feed intake (AFI) were also calculated. The percentages of the giblets and eviscerated carcass to live body weight were recorded after the giblets and carcass were weighed. For the purpose of extracting DNA, blood samples from ducks of each breed were taken and placed in tubes with disodium EDTA as an anticoagulant. For real-time analysis, RNA was taken from the liver and breast muscle of each breed. In terms of economic criteria, each breed's total variable costs (TVC), total costs (TC), total return (TR), net return (NR), values for the difference in net profit, and economic efficiency percent were assessed. In comparison to Pekin breed, the Muscovy breed exhibited higher ultimate BW, BWG, dressing percentages, and liver percentages. However, the Muscovy breed experienced a considerable fall in AFI and FCR. PCR-DNA sequencing of IGFBP3, FGF5, MSTN, PGAM2, ApoVLDL-II, ACACA, SCD, FASN and LPL genes revealed nucleotide sequence variations in the form of single nucleotide polymorphisms (SNPs) between Muscovy and Pekin breeds. Muscovy had a much higher gene expression profile for growth markers than Pekin breed. Muscovy breed displayed greater TR, NR, net profit difference%, and economic efficiency% compared to Pekin ducks. According to this study, Muscovy ducks showed greater growth features than Pekin ducks. Identified SNPs and the gene expression profile of growth promoters, together with economic factors, may serve as proxy indicators for selection the best breed of ducks.

Key words: Growth performance; Single nucleotide polymorphism; Gene expression; Ducks; Economic evaluation