Dietary supplementation of fish protein hydrolysate in high plant protein diets modulates growth, liver and kidney health, and immunity of barramundi (Lates calcarifer).

A 60‐day feeding trial was carried out to investigate the effects of fish protein hydrolysate (FPH) in high lupin meal (LM) diets on growth, health and immunity of barramundi. Fish were fed a fishmeal‐based control diet (FM) and three test diets to replace 75% fishmeal protein in the control diet by lupin meal alone (LM), lupin meal with FPH (LM+FPH) and fermented lupin meal with FPH supplementation (FLM+FPH). Each dietary group was stocked with 120 fish with an initial weight of 6.18 ± 0.08 g and fed three times daily to apparent satiation. Fish fed the LM diet had significantly lowered final body weight and specific growth rate compared with control and the remaining dietary groups (p <.05). The decreased growth performance was further exacerbated by liver steatosis and necrosis in the kidney of LM‐fed fish. Fish fed the FLM+FPH diet had significantly increased white blood cells and protein contents compared with the control. A significant reduction in mortality was observed in fish fed FLM+FPH compared with fish fed the LM diet following a 14‐day challenge with Vibrio harvei. Overall, this study suggests that high LM diets with FPH supplementation could be incorporated into the diet of juvenile barramundi without compromising growth and health. [ABSTRACT FROM AUTHOR]