Abstract:

In the present study, we investigated the effects of lighting conditions on the growth performance, water chemistry and culture environment of GIFT Tilapia (GIFT Oreochromis niloticus). The concrete tanks covered by 13 mm thick red building template was used as the treat group (Group T) under low lighting conditions, and the concrete tanks not covered by template was used as the control group (Group C) under natural lighting conditions. Each group was set with 3 repetitions and 6 concrete tanks were used in total. During the experiment, the method of adding oxygen with the diameter of 70 cm nano disc bottom was used. During the whole experimental period, water temperature (WT) and dissolved oxygen (DO) were monitored continuously. The concentrations of ammonia nitrogen (NH4+-N), total nitrogen (TN), total phosphorus (TP), chemical oxygen consumption (CODMn) and chlorophyll a (Chl-a) were measured by weekly sampling. Commercial compound feed was used to feed tilapia, while the total amount of compound feed was recorded, and the growth index of tilapia was measured at the initial and final of the experiment. The results showed that the survival rate, growth performance and feed coefficient of tilapia was not significantly affected by lighting conditions during the 56 day experiment, while the water quality was significantly affected by the lighting conditions, especially the water temperature, chlorophyll a and CODMn. Therefore, it is more necessary to adjust the water quality of tilapia culture in low light indoor environment, and the bio-floc culture mode may be a new breakthrough because of its advantages of bacteria community stability, not causing the change of pH in water, and not limited by light conditions.