Journal of Environmental Biology

Elevated rearing temperatures increase dietary lipid requirements in GIFT tilapia, Orechromis niloticus (Linnaeus, 1758)

A. Satyakumar, T. Varghese*, T.P. Nathaniel, S. Bhatt, K. Vasanthakumaran, S. Gupta and A.D. Deo     

ICAR-Central Institute of Fisheries Education, Versova, Mumbai-400 061, India

Received: 14 August 2024                   Revised: 24 December 2024                   Accepted: 05 February 2025

*Corresponding Author Email : 4tincy@gmail.com                     

Abstract

Aim: This study investigated the effects of dietary lipid levels and temperature on growth performance, lipid metabolism, and physiological responses in GIFT tilapia juveniles, aiming to optimise feeding strategies under climate warming scenarios.

Methodology: GIFT tilapia juveniles were cultured for 60 days under two temperature regimes (ambient: 28^°C, warm: 33^°C) and three dietary lipid levels (8%, 10%, 12%). Growth parameters, body composition, serum biochemistry, antioxidant enzymes, and liver histology were analysed. A Two-way ANOVA was used to assess the effects of temperature, dietary lipids, and their interaction.

Results: The 12% lipid diet yielded the highest weight gain and thermal growth coefficient at both temperatures, but growth was reduced across all diets at 33^°C. Warm temperature decreased body lipids, lipase activity, and intraperitoneal fat index. Serum protein and globulin levels increased at 33^°C, while glucose and cortisol levels rose with increased dietary lipids and temperature. High temperature negatively affected the antioxidant enzyme activities but was enhanced by higher dietary lipids. Liver histology revealed better regulation of hepatocyte size at 33^°C with increasing dietary lipids.

Interpretation: The study demonstrates that higher dietary lipids could be utilised to enhance the growth of GIFT tilapia in the wake of thermal stress. The complex interactions observed between temperature and diet in regulating lipid metabolism and physiological responses suggest that tilapia farmers may need to adjust feed formulations based on water temperature. With a rise in global temperature, increasing dietary lipid levels may help meet higher energy requirements and support stress adaptation in warmer conditions. This research provides crucial insights for optimising tilapia production in the face of climate change.

Key words: Climate change adaptation, Dietary lipids, Liver histology, Oxidative stress, Thermal stress

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