Effects of Different Dietary Salt Levels on Growth and Salinity Tolerance of Angel Fish (Pterophyllum scalare)

Abstract

This study investigated the effects of dietary salt (NaCl) levels on growth performance and salinity tolerance of angel fish (Pterophyllum scalare). Five diets were supplemented with 0 (control), 7.5, 15, 22.5, and 30 g kg⁻¹ salt, respectively. Over 56 days, weight gain and specific growth rate were similar for the fish fed diets supplemented with 0 (control), 22.5, and 30 g kg⁻¹ salt (P > 0.05), but slightly lower than fish fed the 7.5 and 15 g kg⁻¹ salt diets. Results showed that addition of 7.5 and 15 g kg⁻¹ salt to diets slightly increased specific growth rate (SGR), while decreased food coefficient ratio (FCR) and the highest final weight were observed in fish fed the diet containing 7.5 g kg⁻¹ salt. There was no significant difference in survival rate among groups at experimental period (P > 0.05). At the end of experiment, the angel fish were exposed to salinity stress (6, 9, and 12 ppt). There was no significant obvious trend in survival index after 48-h salinity stress (P < 0.05).

Keywords:

• Angel fish
• dietary salt levels
• growth performance
• salinity tolerance