Effects of replacement of fish oil by sesame seed (Sesamum indicum L.) oil in the diets of til-aqua natural male tilapia
This study evaluated the effects of dietary sesame oil extracted from autoclaved, roasted and fermented sesame seed meal on growth, nutrient utilization and muscle fatty acid composition of Til-aqua natural male tilapia. Four isonitrogenous (crude protein content: 35%) and iso-energetic (Gross energy: 19.36 KJ/g) diets were formulated to contain 3% of either fish oil (FO) or oils extracted from autoclaved (AO), roasted (RO) or fermented (FEO) sesame seed meals. Each diet was assigned to duplicate groups of Til-aqua natural male tilapia (initial average weight, 2.78±0.02 g) using recirculating aquaculture systems for 56 days. Specific growth rate 0.8 (2.93%/day) and metabolic growth rate (9.68 g/kg /day) recorded in the group fed RO diet were significantly lower (P<0.05) than those of AO treatment. Muscle fatty acid compositions were consistent with their dietary values except for di-homo-γ-linolenic acid, 20:3 (n-6), which accumulated in the groups that received diets FO (58.11%), FEO (44.75%) and RO (23.30%). There was a significant increase (P<0.05) in the muscle content of palmitic acid of the group fed diet AO (26.6%) when compared with the control (7.30%), diet RO (18.74%) and diet FEO (11.43%). The study showed that sesame oil can replace fish oil in the diets of tilapia without compromise on growth or nutrient utilization.
Keywords: Fish oil, Sesame seed oil, Fatty acid, Tilapia, Nutrient digestibility