ISSUE FOCUS FEED & ADDITIVE MAGAZINE August 2024 61 25% at the lowest level of digestible dietary N (Figure 2), primarily related to reductions in branchial ammonia excretion. This shows that use of the AmiNova concept in aquatic feed formulations promotes higher N retention and optimises the proportion of N used for protein deposition and growth. Similar results were seen in growth and dissolved N excretion in response to lowering total digestible N in diets for rainbow trout. Reduction or elimination of the target for total digestible N will allow for greater formulation flexibility, and support customers in reducing their environmental footprint and ability to meet stringent regulatory requirements. These results have since been validated in several controlled and field trials, demonstrating the value of the use of this formulation concept, and the amino acid requirements underpinning it. The use of AmiNova, having been developed and validated initially using Atlantic salmon and rainbow trout as model species, can now be assessed for extension to other species where nitrogenous compound requirements are well documented. About David Poppi David Poppi is a Senior Researcher in the Salmonid Nutrition team of Skretting Aquaculture Innovation (Skretting AI) with a PhD in amino acid metabolism in fish, and 19 years of experience in aquaculture industrial and research roles. His main areas of expertise and research at Skretting AI are protein and amino acid utilisation, feed intake regulation, and application of protein raw materials in salmonid diets. Skretting AI is the innovation and product development arm of Skretting, a global leader in aquatic animal nutrition and feed production. About Ramón Fontanillas Ramón Fontanillas is a veterinarian with a PhD in animal nutrition, working as the Principal Researcher in Shrimp and Warmwater Species in Skretting Aquaculture Innovation. Dr. Fontanillas worked in several animal feed industry positions before landing at Skretting in 2004. During his 20-year career in Skretting, he has conducted research on a wide range of topics with several species, but currently focusses on protein, amino acid, energy and mineral requirements of European sea bass, Sea bream, Atlantic salmon, rainbow trout, and warmwater fish species. No statistical difference (p>0.05) Dietary digestible N content Dietary digestible N content Specific Growth Rate (%/d) Feed Conversion Ratio (%) N discharge (g/kg of weight gain) No statistical difference (p>0.05) Dietary digestible N content a ab bc bc c Figure 1. Specific growth rate (±S.D.) and feed conversion ratio (±S.D.) of Atlantic salmon in response to decreasing total dietary N content from a commercial requirement level to a level 15% below the commercial level. N discharge (g/kg of weight gain) 5) Dietary digestible N content a ab bc bc c Figure 2. Dissolved N excretion by Atlantic salmon (±S.D.) in response to decreasing total dietary digestible N content from a commercial requirement level to a level 15% below the commercial level. Different letters above the bars denote significant differences (p>0.05) in proportional N discharge between treatments.
RkJQdWJsaXNoZXIy MTUxNjkxNQ==