Length-Weight Relationship of Labeo rohita Fingerlings Fed Diets Supplemented with Commercial Zinc Oxide Nanoparticles

Abstract

The length-weight relationship (LWR) is an important biological tool for assessing fish growth patterns and evaluating the influence of nutritional interventions in aquaculture. This study investigated the effect of dietary supplementation with commercial zinc oxide nanoparticles (C-ZnO NPs) on the length-weight relationship of Labeo rohita fingerlings. Healthy fingerlings (initial mean body weight: 2.23±0.38 g; total length: 5.74±0.28 cm) were randomly assigned to four dietary treatments: a basal diet (control) and basal diets supplemented with commercial ZnO nanoparticles at 10, 100, and 200 mg/kg of feed. Fish were reared in triplicate for 90 days under controlled laboratory conditions, and water quality parameters were maintained within the recommended range throughout the experiment. The relationship between body length and weight was evaluated using regression analysis. A strong positive association between body length and weight was observed in all dietary treatments, with coefficients of determination (R²) ranging from 0.7824 to 0.8794. The control group exhibited the highest coefficient of determination (R²=0.8794), while the nanoparticle-treated groups recorded R² values of 0.7942, 0.7824, and 0.8253 for the 10, 100, and 200 mg/kg treatments, respectively. These findings indicate that dietary supplementation with commercial ZnO nanoparticles maintained a consistent relationship between body length and weight without markedly altering the overall growth pattern of L. rohita fingerlings under the experimental conditions. The present study provides baseline information on the length-weight relationship of L. rohita following dietary supplementation with commercial ZnO nanoparticles and contributes to the understanding of nanoparticle-based mineral nutrition in aquaculture.