Haematological Responses of Labeo rohita to Dietary Kappaphycus alvarezii sap

Abstract

The study evaluated the effects of graded dietary inclusion levels of Kappaphycus alvarezii sap on the haematological responses of Labeo rohita fingerlings during a 60-day feeding trial. Five dietary treatments including Control (0%), T1 (5%), T2 (10%), T3 (15%), and T4 (20%) were administered in triplicate using commercial feed enriched with the respective sap concentrations. Water quality parameters remained within optimal limits throughout the experiment. Significant improvements (p < 0.05) were recorded in several haematological indices, with the highest responses observed in the T4 group, including red blood cell count (1.33 × 10⁶ cells mm⁻³), haemoglobin concentration (8.36 g%), platelet count (62.67 × 10³ cells mm⁻³) and haematocrit (28.5%). White blood cell counts and erythrocyte indices (MCV and MCHC) also showed significant but moderate increases with increasing dietary inclusion levels. These responses indicate enhanced physiological condition and improved haematological stability, suggesting a positive influence of dietary sap supplementation on fish health. The findings establish K. alvarezii sap as a promising natural functional feed additive for freshwater aquaculture. Based on the observed haematological responses, a 20% inclusion level appears optimal for improving blood health and physiological status in L. rohita. The study underscores the potential of seaweed-derived bioactives in supporting sustainable and health-oriented freshwater aquaculture practices.