Effects of Dietary Mentha piperita Supplementation on Growth Performance, Feed Utilization, and Proximate Composition of Labeo rohita Fingerlings

Fish is a preferred and affordable source of high-quality animal protein for humans. Labeo rohita is one of the most important Indian major carps cultured in polyculture systems. Mentha piperita (peppermint) is a medicinal plant belonging to the Lamiaceae family, with bioactive compounds that may enhance growth and feed utilization in fish. The present study investigated the effects of dietary peppermint supplementation on growth performance, feed utilization, and proximate body composition of L. rohita. Fingerlings (n = 10 per tank) were acclimatized for 4–6 days before the 28-day experimental trial. Four dietary treatments were prepared: T0 (control, 0 g/kg), T1 (100 g/kg), T2 (200 g/kg), and T3 (300 g/kg) peppermint supplementation. Growth performance parameters, including weight gain, fork length, total length, and specific growth rate (SGR), were measured weekly. Feed conversion ratio (FCR) and body composition (moisture, crude protein, crude fat, ash) were also evaluated. Results indicated that dietary peppermint significantly improved growth performance of L. rohita. Weight gain, total length, fork length, and SGR were highest in T3 (16.94 ± 1.954 g, 9.74 ± 0.492 cm, 6.79 ± 0.643 cm, 1.71 ± 0.583, respectively). FCR was lowest in T3 (best feed utilization), while moisture and crude fat were highest in T2 (75.51 ± 0.05%, 1.32 ± 0.04%), and crude protein and ash content were highest in T3 (22.26 ± 0.05%, 0.98 ± 0.04%). These results suggest that dietary peppermint supplementation, particularly at 300 g/kg, enhances growth performance, feed efficiency, and body composition of L. rohita. Data were expressed as mean ± SD, and statistical differences among treatments were determined using one-way ANOVA followed by Tukey’s post hoc test.