Plant protein (PP) based feed is desirable to maintain the sustainable growth of aquaculture. However, the presence of anti-nutritional factors, imbalanced nutrient content, and low digestibility limits their utilization. Additionally, PP based feed may deteriorate fish fillet quality. Therefore, using feed additives in PP based feed can potentially improve their utilization in fish and improve the fillet quality. The aim of the present study was to evaluate the effects of dietary supplementation of additive mixture in PP diets (~30% soy) on the growth and fillet quality of rainbow trout.
Two thousand fish (2.22 g) were distributed in four groups with 5 replicates (100 fish/tank) and fed four isonitrogenous (42% CP) and isolipidic (20% lipid) diets: control (30% fish meal, FM), PP, PP+A1 (krill meal, taurine and organic selenium) and PP+A2 (proline, hydroxyproline and vitamin C) for 28 weeks.
Dietary supplementation of additives in PP diets improved the growth performance and feed efficiency of fish compared to PP group but comparable to FM (figure 1). Fish fillet quality was also affected by additives (table 1), hardness, gumminess and chewiness of PP+A2 group was higher than other groups, whereas gumminess and chewiness of FM and PP+A1 groups were higher than those of PP-group. The higher value of chroma and lower value of hue-angle in PP+A1 group indicates improved color of fish fillet. Additionally, muscle fibre requirement pattern using muscle fibre count and genes responsible for myogenesis are being analyzed.
Conclusively, PP based diet exhibited negative effects on growth and fillet quality of rainbow trout, which can be alleviated by the supplementation of additive mixture.