Table 2.
Fish performance and processing and fillet quality attributes for each diet/density treatment group at study's end
| Parameter | Value (mean ± standard error) |
|||
|---|---|---|---|---|
| Fishmeal diet |
Grain-based diet |
|||
| High density | Low density | High density | Low density | |
| Fish performance | ||||
| Final wt (g)a | 925 ± 12 | 807 ± 26 | 663 ± 40 | 691 ± 46 |
| Survival (%)a | 96.4 ± 0.5 | 97.1 ± 0.7 | 97.9 ± 0.2 | 97.6 ± 0.5 |
| FCR (overall)a | 1.18 ± 0.02 | 1.15 ± 0.03 | 1.02 ± 0.06 | 1.10 ± 0.01 |
| TGC (overall) | 2.46 ± 0.04 | 2.45 ± 0.04 | 2.42 ± 0.07 | 2.33 ± 0.08 |
| Processing attributes | ||||
| Dress yield (%)a | 86.1 ± 0.4 | 85.4 ± 0.5 | 87.7 ± 0.4 | 88.9 ± 0.4 |
| Fillet index (%) | 49.8 ± 0.5 | 49.7 ± 0.6 | 50.3 ± 0.3 | 50.8 ± 0.5 |
| Fillet attributes | ||||
| Cook yield (%) | 84.3 ± 0.6 | 84.8 ± 0.5 | 85.0 ± 0.4 | 84.4 ± 0.5 |
| Texture (Kramer g/g wt)b | 340 ± 20 | 334 ± 18 | 316 ± 11 | 344 ± 11 |
| Proximate analysis | ||||
| Moisture (%) | 70.6 ± 0.3 | 70.4 ± 0.2 | 70.4 ± 0.2 | 70.8 ± 0.3 |
| Fat (%) | 8.8 ± 0.4 | 8.7 ± 0.3 | 9.1 0±.3 | 8.8 ± 0.4 |
| Protein (%)a | 20.2 ± 0.2 | 20.4 ± 0.1 | 20.6 ± 0.1 | 20.7 ± 0.1 |
| Ash (%) | 1.2 ± 0.0 | 1.3 ± 0.0 | 1.3 ± 0.0 | 1.3 ± 0.0 |
| Fatty acids (mg/g tissue) | ||||
| Omega-3 | ||||
| ALA (C18:3n3) | 0.75 ± 0.23 | 0.84 ± 0.19 | 0.86 ± 0.27 | 1.18 ± 0.04 |
| EPA (C20:5n3)a | 3.41 ± 0.13 | 3.05 ± 0.17 | 2.10 ± 0.09 | 2.19 ± 0.07 |
| DHA (C22:6n3)a | 11.3 ± 0.65 | 10.3 ± 0.44 | 8.92 ± 0.23 | 10.0 ± 0.77 |
| Total omega-3a | 15.5 ± 0.68 | 14.1 ± 0.34 | 11.9 ± 0.31 | 13.8 ± 0.57 |
| Omega-6 | ||||
| DGLA (C20:3n6) | 1.13 ± 0.17 | 1.01 ± 0.26 | 1.00 ± 0.24 | 1.13 ± 0.16 |
| Eicosadienoic acid (C20:2n6)a | 9.65 ± 0.24 | 9.55 ± 0.20 | 13.2 ± 0.24 | 13.7 ± 0.14 |
| Total omega-6a | 10.8 ± 0.13 | 10.6 ± 0.25 | 14.2 ± 0.16 | 14.8 ± 0.23 |
a
Parameter showed a statistically significant difference between diet treatment groups using ANOVA (P < 0.05); no statistical differences were determined between density treatment groups, and no statistical interactions between treatments were detected.
b
Kramer shear force is a measure of sample firmness. Samples are sheared by blades and force-deformation curves, from which the Kramer values are derived, are obtained.