Efficacy of phytogenic extracts on growth performance and health of tilapia (Oreochromis niloticus × O. aureus)

Abstract

The present study was conducted to evaluate the efficacy of phytogenic extract on growth and health of tilapia. Three experimental diets were designed as the basal diet (Con) and phytogenic extract (Flourishing, F) supplemented diets at 0.5 and 1 g/kg inclusion (F-1 and F-2), which the phytogenic additive was extracted from Eucommia ulmoides, Astragalus membranaceus, Lonicera japonica and Codonopsis pilosula. The three diets were fed to juvenile tilapia (14.0 ± 0.1 g) with 30 fish per cage, and three replicate cages from the three groups were placed in one indoor concrete pool (a total of three pools were used). After 8 weeks of feeding, the weight gain was significantly increased, and feed conversion ratio was decreased in F-2 group (P < 0.05) when compared to the control. Both levels of phytogenic extract significantly promoted the retentions of protein and lipid and the apparent digestibility coefficient of dry matter and protein (P < 0.05). The activity of superoxide dismutase and the levels of white blood cells, haemoglobin and glutamic pyruvic transaminase were also significantly increased by the supplementation of phytogenic extract (P < 0.05). The villus height in anterior intestine was significantly enhanced in F-1 and F-2 groups (P < 0.05). After challenging with Aeromonas hydrophila, the cumulative mortality was significantly declined in F-1 and F-2 groups (P < 0.05). In summary, the dietary supplementation of phytogenic extract at 1 g/kg feed could provide positive efficiency on growth, nutrient utilization, immunity, gut morphology and disease resistance of tilapia under the present conditions.