Effect of dietary protein level on growth and metabolism of GIFT juveniles reared in inland ground saline water of medium salinity

ABSTRACT

A 60-day feeding trial was conducted to study the effect of varying levels of dietary protein on growth metrics, hemato-biochemical status, and metabolic responses of GIFT tilapia juveniles reared in inland ground saline water (IGSW) of 15 g/l. A random distribution of 315 acclimated fish (avg. wt. 4.01 ± 0.01 g, stocking density 15 fish/tank) was done in seven experimental groups—20% (CP²⁰), 25% (CP²⁵), 30% (CP³⁰), 35% (CP³⁵), 40% (CP⁴⁰), 45% (CP⁴⁵), and 50% (CP⁵⁰)—in triplicates following a completely randomized design (CRD). Weight gain (WG), metabolic growth rate (MGR), feed efficiency ratio (FER), and protein growth rate (PGR) showed higher quadratic relations (R² = 0.93, 0.96, 0.92, 0.90 respectively) with highest (P < 0.05) values in the CP⁴⁰ group. Protein efficiency ratio (PER) significantly (P < 0.05) decreased with increase in dietary protein levels. Higher (P < 0.05) quadratic relations of muscle and hepatic AST (R² = 0.71, 0.75) and ALT (R² = 0.77, 0.69) activities, hemoglobin (Hb) content (R² = 0.87), hematocrit (Hct), value (R² = 0.93), and red blood cell (RBC) count (R² = 0.88) were found in groups fed higher levels of dietary protein than their lower protein-fed counterparts. Muscle LDH and MDH activities were the highest (P < 0.05) in CP²⁰ and CP⁵⁰ group respectively with strong linear and quadratic relationships. The lowest (P < 0.05) serum glucose level was found in the CP⁴⁰ group. Second-order polynomial regression analysis indicated that 41.85% dietary protein is optimum with respect to growth metrics, nutrient utilization, and metabolic status of GIFT tilapia juveniles in IGSW of 15 g/l.

KEYWORDS:

• Dietary protein
• growth
• metabolic enzymes
• haemato-biochemical status
• Inland Ground Saline Water (IGSW)
• GIFT juveniles

Acknowledgments

The authors are grateful to the Director of the ICAR-Central Institute of Fisheries Education, Mumbai, India, for providing well-equipped laboratories for completing the research work.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The supporting data of the findings of this study are available from the corresponding author upon reasonable request.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the United States Agency for International Development as a part of the Feed the Future Initiative under the CGIAR Fund (Award no. BFS-G-11-00002) and the predecessor fund the Food Security and Crisis Mitigation II grant (Award no.EEM-G-00-04-00013), which provided the PhD fellowship program, and the World Bank ICAR-National Agricultural Higher Education Project (ICAR-NAHEP), which provided financial support.