Larval width as indicator of growth rate and effect of larval classification on final body composition and flesh quality in cultured gilthead seabream (Sparus aurata , L.)

Abstract

Summary The objective of this study was evaluating the effects on the growth rate and flesh quality of separating larvae according to their larval width in cultured gilthead seabream (Sparus aurata, L.). Progeny from two broodstocks (A and B) were divided into two groups according to larval width: heads (being the larger specimens) and tails. After 18 months both groups were analysed to evaluate growth, carcass traits and proximal composition. The head specimens reached a larger size and showed a greater level of well-being and degree of nourishment. Total body and fillet composition in general were found to be as expected for this species. Some differences were found in total body composition between head and tail specimens in both batches, and in the fillet composition in batch B (higher fat and lower moisture content in the head specimens). Sensory analyses were carried out using untrained panelists, who were unable to distinguish between the head and tail samples in batch A, whereas differences were noticeable in batch B. Samples from the head group were judged to be tastier and juicier, a consequence of their higher fat content. Hence, fish separation according to larval width is an effective tool to separate progeny into slow and fast growing groups, whereas the total body and fillet analyses and a sensory test ensure that the selection does not generate negative effects on the product quality.