Whey protein concentrate powder as a growth promoter and an immunostimulant agent for Oreochromis niloticus (Linnaeus, 1758) fingerlings

      Due to their nutritive value and functionality, whey proteins have been used in many food applications. The efficacy of adding different levels (0, 5, 10 and 20 g kg^–1 diet) of whey protein concentrate powder (WPCP) was addressed on the growth performance, feed utilization, and the immune responses of Oreochromis niloticus fingerlings in the current study for 8 weeks. A significant increase was observed in the growth performance (final weight, total weight gain, average daily gain, relative growth rate, and specific growth rate), the feed utilization (feed conversion ratio, protein efficiency ratio, protein productive value, and energy utilization), and the whole-body composition (dry matter, and crude protein) parameters. These levels also significantly improved both the hematological parameters (hemoglobin, red blood cells, packed cell volume, and platelets), and the immune responses indicators (white blood cells, lymphocytes, and serum immunoglobulin M) of the O. niloticus fingerlings. Partially, in all tested parameters, the addition of the high-level 20g WPCP kg^–1 diet showed a remarkable superiority among other levels. Remarkably, the beneficial use of WPCP at the level of 20 g kg^–1 diet was proved as a promising growth promoter and immune stimulant agent for O. niloticus fingerlings, and may in return, increase fish productivity, health, and profitability in fish farms.