The Interaction Between Dietary Fat Level, n-3 LC-PUFA, and Zinc on Their Postprandial Absorption Kinetics in Atlantic Salmon (Salmo salar)

Two short-term feeding trials were conducted on Salmo salar, with the interaction between dietary zinc (Zn) and fat level in trial 1 and with the interaction between dietary Zn and n-3 long-chain polyunsaturated fatty acids (n-3 LC-PUFA) in trial 2, focusing on postprandial plasma parameters, intestinal Zn and fat uptake and transport. After 4-week feeding interventions, samples were collected at different postprandial time points, ranging from 0 to 36/38 h after feeding. Results showed that increased Zn level in feed significantly increased the postprandial plasma Zn level in trial 1 (8–9°C). On the contrary, the postprandial plasma Zn level was not affected by the dietary Zn under higher temperature conditions (trial 2, 10−12°C). Further, analyzed markers related to intestinal Zn uptake and transport were not affected by dietary fat level and n-3 LC-PUFA. In addition, analyzed markers related to intestinal fat uptake and transport were not affected by dietary Zn. Intestinal Zn transport plays a key role in regulating body Zn storage, while intestinal fat transport influences lipid accumulation within the intestine. Understanding how these processes respond to dietary components is critical for maintaining fish health and welfare.