Use of ultrasonographic imaging for non-invasive carcass yield prediction in Nile tilapia (Oreochromis niloticus)

Ultrasonography has been used to collect data on internal structures in terrestrial species for many decades and has proven an important tool for measuring meat yield-related phenotypes. However, application of this technique to selective breeding of aquaculture species is recent, and its use for recording yield traits of economic importance has not yet been standardized for many species. The aim of the present study was to standardize ultrasound image collection methods for assessment of fillet yield phenotypes in Nile tilapia. Ultrasound images were obtained from 30 tilapia with mean weight of 645 g (± 165.89) using the VINNO Q device. Data on fillet cross-sectional area at three standard points along the length of the fish were analyzed with the aid of ImageJ software. The results were evaluated by Student’s t-test and correlated by the Pearson method. The data obtained by ultrasonography proved reliable, given the high correlations (0.78–0.98) between estimates made using images collected at those standard points and subsequent evaluation from measurements made directly upon the carcass. The correlations for fillet yield (0.51–0.58) and belly fillet yield (0.27–0.42) were moderate. The area averages and depth averages collected at the three standard points showed high correlations with fillet yield (0.58–0.54) and sirloin fillet yield (0.56–0.60). We concluded that the use of ultrasonography in collection of meat-yield phenotypes of economic interest is an effective method for use in direct selection of broodstock candidates in selective breeding programs for Nile tilapia.