Effects of magnetic water and feeding rate on growth performance and immunity of Nile Tilapia (<i>Oreochromis niloticus</i>)

Abstract

Objective: The present study was designed to investigate the effect of magnetic water treatment technique and different feeding rates on growth performance, feed utilization, water quality parameters, chemical composition and intestinal histomorphometric parameters of monosex Nile tilapia (Oreochromis niloticus).
Design: Experimental study with a factorial design.
Fish: A total of 2880 apparently healthy monosex Nile tilapia (O. niloticus) with an average initial body weight of 69.86 ± 0.8 g were randomly distributed into 18 concreate ponds.
Procedures: Experimental fish were fed on commercial diet (30.1% protein and 4600 Kcal GE/kg diet) based on three levels of feeding rate 3, 4 and 5% from fish biomass for both treated and control groups. Water was treated with magnetic waves at 0.2 Tesla (Tesla= 2000 Gauss) compared to the control group water (zero Tesla). Growth performance parameters, feed utilization, chemical composition and intestinal morphometric analysis were calculated in all groups at the end of the experiment after eight weeks.
Results: The results indicated that growth performance, feed utilization and intestinal histomorphometric analyses improved significantly (P<0.01) in magnetic water groups compared to control groups at the three levels of feeding rate. In addition, water physicochemical parameters including Ammonia (NH₄), Nitrate (NO₃), Nitrite (NO₂), PH and dissolved oxygen (DO) significantly improved in magnetic water treated groups at the three feeding rate levels.
Conclusions and clinical relevance: In conclusion, magnetic treatment of water could improve water quality parameters, fish growth performance, feed utilization, and intestinal histomorphometric analyses at different feeding rate.