Vol. 7, Issue 4, Part B (2025)

Phytogenics, or plant-based additives, are pivotal for growth enhancement and disease resistance in cultured fish diets. A 60-days feeding trial was carried out in hapas (1m×1m×1.2m) within a grow tank (5 m×5 m×1.5 m) at the Department of Aquaculture, Agriculture hatchery complex. The study aimed to assess growth performance, survival, and gut flora of Cyprinus carpio fed with varying levels of Zingiber officinale rhizome extract. An initial cohort comprising 450 juveniles (fry) of C. carpio, averaging 2.55±0.03 g in weight and 4.9±0.68cm in length, were fed with diets containing 27.15% crude protein, included four concentrations of Z. officinale rhizome extract (1%, 2%, 3%, and 4%), along with a control group (0%); feeding three times a day for a total of 60 days, with each meal amounting to 5% of their body weight. Fish group receiving the diet containing 3% Ginger rhizome extract, showed the highest values for growth performance parameters (p<0.05), including average harvesting weight (10.33±1.32 g/fish), total harvesting weight (247.82±31.60 g/hapa), daily weight gain (0.13±0.01g/fish/day), specific growth rate (2.33±0.18%/ day) in comparison with control group. The mean initial total bacterial count of fries was observed (1.38×109 cfu/ml) and notable variances (p<0.05) were observed among groups fed with varying level of Ginger. The least total bacterial count was recorded in group fed 3% ginger rhizome extract on observation at 20 days (1.75×108±2.64×106 cfu/ml), 40 days (1.9×107±4.23×106 cfu/ml), and 60 days (1.62×106±3.60×104 cfu/ml). Similarly, the effects of varying level of ginger rhizome extract on the water quality parameters were not significantly different (p>0.05). The study concluded that supplementing the diet of cultured C. carpio with 3% Z. officinale rhizome extract effectively fosters growth and reduces the bacterial load in the gut of fish.