Effects of temperature on the zootechnical performances and physiology of giant gourami (Osphronemus goramy) larvae

Abstract

The influence of temperature on zootechnical performances and physiology was assessed in giant gourami (Osphronemus goramy) larvae. Larvae aged ten days post-hatching were reared at five temperature treatments (22.5, 25.0, 27.5, 30.0 and 32.5 °C, three replicated per treatment) in indoor closed recirculating systems until they reached, at least, the commercial size of 2.5 cm in total length (i.e. rearing time of 21 to 42 d depending on the temperature). Samples of larvae were collected every week. Survival, growth, and feed intake were used as main indicators of zootechnical performances. In addition, concentration of glucose and cortisol and proximate composition of the young life-stages giant gourami were compared to assess effects of temperature on their physiology. Results showed that temperature strongly affected growth of giant gourami larvae with significantly increased observed at the increasing tested temperatures (from 57.2 ± 9.3 mg to 431.9 ± 64.2 mg of body weight after three weeks, p < 0.05). The increased growth can be related to changes in metabolism, feed intake and feed use efficiency. Based on cortisol and glucose values, we recommend to maintain rearing temperature at 30.0 °C for both optimizing growth and avoid physiological impairments in giant gourami larvae. The consequences of larval rearing at stable temperature (30.0 °C) should be further investigated in the nursery and grow-out outdoor phases.