The impacts of seasonal variation on the immune status of Nile tilapia larvae and their response to different immunostimulants feed additives.

摘要: Abstract Few data are available on the thermal tolerance of Nile tilapia fish larvae in relation to their immune status and survival. The aims this work were evaluate one day old (Oreochromis niloticus) larval stage collected at beginning (March), middle (August) end (October) hatching season through morphometric assessment parameters including yolk sac diameter, body length width as well expression some immune-related genes (rag, sacs tlr), inflammatory (il1b il8) stress related (hsp27, hsp70). Also, compare effect three different immunostimulants (β-glucan, Vitamin C, methionine/lysine amino acids mix) studied two variant temperatures (23 ± 1 °C 30 ± 1 °C) experimental study for 21 days. is affected by fluctuation throughout reflected altered size, length, larvae, best performances was observed (March). High temperature (30 °C) suppress responses downregulation all under study, mask any effects immunostimulants, increased mortality suggesting narrow range compared with adult fish. We recommend use acid mix immunostimulant it reduces percentage improve cellular response. β-glucan should be prohibited during developmental induced highest percentage.