Feed and feeding management in aquaculture: concept, technological scheme and practices

Feed has become a key determinant of the benefits of aquaculture practices, as the proportion of fed aquaculture now exceeds 70% of global aquaculture production. Enhancing fish growth and feed utilization efficiency, particularly dietary protein retention efficiency (NRE), is a common objective in breeding, nutrition, feed, and aquaculture management research. Feed and feeding management (FFM) is defined as a method to improve the growth and health of farmed animals while reducing production costs and negative impacts of farming practies on natural resources and the environment by providing high-quality, cost-effective diets at appropriate feeding regimes. As an integraton of feed management and feeding management, FFM is recognized as one of the most important components in optimizing the aquaculture mode (AM). Nutrient requirements, diet formulation, and feeding of aquatic animals belong to different displines, such as nutrition, feed science, and feeding ecology, respectively. Although numerous attempts focused on investigating nutrient requirements, feed and feeding of fishes, however, few studies concern the integration of feed and feeding to establish FFM under specific farming conditions for the fish species commercially important to fed aquaculture. In this review, the author defined the concept of FFM based on the studies of feed management or feeding management of fishe and elucidated its role in optimizing the aquaculture model. First, the author indicated the technology diagram for optimizing FFM includes: ① determining the nutrient requirements of the farmed animals, ② designing high-quality, cost-effective diet formulas using feed ingredients that are rich in nutrients, low in anti-nutritional factors, and consistently available to meet the nutrient requirements of farmed animals, ③ determining the optimal feeding regimes for farmed animals fed with diets formulated according to the high-quality, cost-effective diet formula, ④ integrating the high-quality feed and optimal feeding regimes to determine the FFM scheme and assessing its benefits on production, production cost, natural resource depletion, and environmental pollution. Second, the author briefly reviewed researche on establishing FFM for the large yellow croaker (Larimichthys crocea), largemoth bass (Micropterus salmoides), golden pompano (Trachinotus ovatus), and cuneate drum (Argyrosomus amoyensis) and presents prelimnary results on FFM schmes for these fish species, including optimal dietary protein and lipid levels, minimum fish meal content in diet formulas, and optimal feeding frequency and ration levels. Specifically: ① For L. crocea reared in net pens, the optimal dietary protein level, lipid level, and protein-to-energy ratio were 490–520 g/kg, 100 g/kg and 27.6 MJ/kg, respectively, with a minimum dietary fish meal content of 160 g/kg. The optimal feeding frequency and ration level were 2 meals/d and 2.1% BW/d. ② For M. salmoides reared in earth ponds, the optimal dietary protein and lipid levels were 480–510 and 120 g/kg, respectively, with a minimum dietary fish meal content of 80 g/kg. The optimal feeding frequency and ration level were 3 meals/d and 2.2% BW/d. ③ For T. ovatus reared in net pens, the optimal dietary protein and lipid levels were 450−490 and 110 g/kg, respectively, with a minimum dietary fish meal content of 140 g/kg. The optimal feeding frequency and ration level were 3 meals/d and 5.7% BW/d. ④ For N. miichthioides reared in net pens, the optimal dietary protein, lipid and energy levels were 450 g/kg, 150 g/kg and 19.0 MJ/kg, respectively, with a minimum dietary fish meal content of 75 g/kg. The optimal feeding frequency and ration level were 1 meal/d and 2.1% BW/d. Finally, the author provided suggestions for establishing and optimizing FFM schemes for fish farming, which included: ① considering the effects of fish species and genetic characteristics as well as environmental conditions on FFM scheme, ② ensuring the reliability and accurancy of the data (nutrient requirements of the farmed fish and quality assessment of feed ingredients) used in diet formula, ③ recognizing the interactive effects between diet formulation and feeding regimes on fish growth and feed utization efficiency, ④ evaluating the benefits of the FFM scheme based on long-term field experiments and the their impact on ecosystem service values.