Aquaculture Reports (Jul 2021)
Synergistic effects of the soapbark tree, Quillaja saponaria and Vitamin E on water quality, growth performance, blood health, gills and intestine histomorphology of Nile tilapia, Oreochromis niloticus fingerlings
Abstract
This study aimed to evaluate the synergistic effects of Quillaja saponaria (QS), and Vitamin E (VE) on water quality, fish performance, and health of Oreochromis niloticus fingerlings. Fish (N = 120, 12.75 ± 0.289 g) were randomly distributed in triplicates into four experimental groups. (1) the control group (CG), fish received a basal diet; (2) the Quillaja saponaria group (QS), fish received a basal diet containing 300 mg kg−1 QS extract; (3) Vitamin E group (VE), fish received a basal diet supplemented with 400 mg kg−1 VE; and (4) QS/VE group, fish received a basal diet supplemented with a mixture of 300 mg kg−1 QS extract and 400 mg kg−1 VE. Fish fed experimental diets (30/6, protein/lipids ratio) for 60 days. Results revealed a significant decrease of total ammonia nitrogen and unionized ammonia in fish fed QS/VE, VE, and QS compared to CG. Fish provided QS and/or VE showed a significant improvement in growth and feed utilization indices compared to CG (P < 0.05), with the best results in QS/VE group. QS and/or VE's dietary supplementation did not improve hematological parameters. However, a significant improvement of serum analyses (total protein, albumin, globulin, A/G ratio, cholesterol, and triglycerides) was recorded in fish fed QS and/or VE compared to CG with the best values in QS/VE. Digestive enzyme activity (lipase, amylase) and oxidative parameters (SOD, CAT) were significantly increased with QS and/or VE dietary supplementation, and the best findings were recorded in QS/VE. Gill necrotic tissues were alleviated in fish fed QS or/and VE. The intestinal health (villi length, villi surface area, and goblet cells count) showed a significant improvement by dietary QS or/and VE, with the best findings in fish received QS/VE. In conclusion, QS and/or VE's dietary supplementation improves water quality, fish performance, blood health, gills, and intestine health of Nile tilapia.
