Global Veterinaria 17 (6): 521-531, 2016 ISSN 1992-6197 © IDOSI Publications, 2016 DOI: 10.5829/idosi.gv.2016.521.531 Corresponding Author: Ahmed Farouk, Animal Production, Faculty of Agriculture, Damietta University, Egypt. 521 Combined Effect of Pond, Lipid Source and Level in Survival and Growth Performance of Over-Wintered Nile Tilapia, Oreochromis niloticus Mohamed T. Shehab El-Din, Ahmed F. Fath El-Bab and Mohamed A. Mostafa 1 2 3 Central Laboratory for Aquaculture Research at Abbassa, Fish Health, (Sakha Unit), Egypt 1 Animal production, Faculty of Agriculture, Damietta University, Egypt 2 Central Laboratory for Aquaculture Research at Abbassa, Fish Production, Egypt 3 Abstract: This study aimed to investigate the effect of lipid source (Sunflower or fish oil and mixture of 1:1 sunflower and fish oil). For each lipid source, two lipd level were tested (2.5 or 5%). Therefore, six experimental diets were formulate and fed to over-wintered mono sex males, Oreochromis niloticus reared in two pond types (Concrete ponds or earthen ponds, hapas). The experiment was carried out during the period from 4 of th December 2014 to the 12 of August 2015. Twelve treatments of two replicates were fed a diet containing 32% th crude protein. While T1 contained 2.5% sunflower oil, T2 2.5% fish oil, T3 2.5% of a mixture between sunflower and fish oil, T4 5% sunflower oil, T5 5% fish oil and T6 5% mixture of both sunflower and fish oil. Fish of the first six treatments (1-6) were reared in concrete ponds and repeated in hapas to represents additional six treatments (7-12). Samples from each treatment were taken during cool and warm months for the evaluation of using different concentrations and types of lipids on the biochemical parameters, growth performance and health status. Results showed that T4 gave the most improvement concerning biochemical parameters. T6 gave the best growth performance parameters. On the other hand, the first three treatments containing the lower lipid level (2.5%) suffered some fungal infection (Saprolegniosis). Moreovere, T7 showed the highest biochemical parameters when samples were taken in the summer season and T9 showed the better growth performance. Treatments containing the high lipids level (5%) either single or mixed suffered from mixed bacterial infection especially in warmer months. Generally we can concluded that, fish diets contained the higher lepid level (5%) of mixed oils are of great importance for over-wintered stocks while lower lipd level (2.%) is sutible for warm seasons. Key words: Lipid Rations Nile Tilapia Over-Wintering Growth Performance INTRODUCTION constructed tanks or in earthen ponds. In Egypt, the Tilapias are warm water fish and their natural season when water temperature varies from 6-20°C. Many geographical evidence tolerating a relatively wide range ectotherm suffer from their sensitivity of low ambient of temperatures (8-42°C). No growth at temperatures temperature in which extreme cold can cause mass below 16°C and does not survive at temperature below mortalities [6]. Over-wintering fish therefore presents a 10°C for more than a few days. Activity and feeding serious problem. become reduced when the temperature falls below 20°C Fish oil is a major dietary lipid source used in tilapia and stops completely at around 16°C. Reproductive feeds. Other than providing a source of energy and activities occur above 22°C [1-3]. essential fatty acids, it is commonly used to coat the There are various culture methods practiced by fish extruded pellets to improve the palatability and farmers to raise fishes either for sale or for family appearance of the feed. Other important functions of consumption. Fish may be raised in big bowls, in unused lipids include aiding in absorption of fat-soluble vitamins, canoes and in depressions that can hold water either in precursors of hormones and prostaglandins and as majority of fish farmers do not feed fish during winter