Impact of Varying Protein Levels on the Growth Rate of Labeo rohita Reared in Glass Aquaria

Objectives. Aquaculture is an important technique used worldwide for the production of aquatic species. In this study, a monoculture experiment was performed to estimate the growth performance of Labeo rohita fingerlings under the influence of varying protein feeds used in various combinations in an intensive rearing system. It was found that different dietary protein levels significantly affected the growth rate of the above fish species, with an optimal protein level resulting in the highest growth performance. Previous studies showed that protein levels in the diet of Labeo rohita can influence growth, food conversion ratio, protein efficiency ratio, survival, and body composition. For instance, a diet containing 35% protein was found to significantly enhance growth, as compared to diets with lower or higher protein levels. Methodology. Feeding trials were conducted to estimate the efficacy of the varying concentrations of dietary protein on the growth of Labeo rohita fingerlings in a glass aquaria for 75 days. The stocking density was 20 fish/aquarium. Diets containing 25%, 30%, and 35% protein were tested against a control containing 12% crude protein. The experiment was performed in the triplicate aquaria of glass. Fish were given feed at the rate of 4% of their body weight twice a day. Their growth performance was evaluated by measuring mean body weight gain (BWG), mean length gain (LG), feed conversion ratio (FCR), specific growth rate (SGR), and survival rate (SR) in different treatment groups. The proximate analysis of fish meat samples was conducted at the end of experiment. Results. In the aquaria, fish fingerlings fed with 35% diet showed significantly greater weight gain (9.09 ± 0.09 g) as compared to those on other diets and control diet (6.8 ± 0.20). Simultaneously, a substantial increase in length gain was observed in fingerlings at 35% diet  (8.2 ± 0.05), while the lowest weight gain (3.5±0.24g) was noted in those on control group diet. On the other hand, water quality variables, such as pH, temperature, dissolved oxygen, and electric conductivity remained constant. Conclusion. It was concluded that a higher level of protein in the feed of Labeo rohita is directly related with the increased growth rate of fish.