Effects of Apple Polyphenols and Taurine on Growth Performance, Tissue Morphology, and Lipid and Glucose Metabolism in Rice Field Eel (Monopterus albus) Fed High Oxidized Fish Oil

Table 1

Formulation and proximate composition of the diets.

Ingredients	Control	POV600	AP	POV800	TA
Peruvian steam fish meal^a	40.00	40.00	40.00	40.00	40.00
Soy protein concentrate^a	20.00	20.00	20.00	20.00	20.00
Beer yeast^a	5.00	5.00	5.00	5.00	5.00
α-Starch^a	18.00	18.00	18.00	18.00	18.00
Flour^a	10.96	10.96	10.46	10.96	10.76
Fish oil^a	3.00	3.00	3.00	3.00	3.00
Premix^b	1.00	1.00	1.00	1.00	1.00
Monocalcium phosphate^c	1.20	1.20	1.20	1.20	1.20
Choline chloride^d	0.80	0.80	0.80	0.80	0.80
Ethoxyquin^e	0.01	0.01	0.01	0.01	0.01
Calcium propanoate^f	0.03	0.03	0.03	0.03	0.03
Apple polyphenols^g			0.50
Taurine^g					0.20
Total	100	100	100	100	100
POV (meq·kg^−1)^h	9.53	611.48	616.24	816.64	803.57
Proximate analysis (%)
Crude protein	46.11	45.84	46.19	46.88	46.69
Crude lipid	5.77	6.02	6.08	5.71	5.74
Ash	10.03	9.89	10.16	10.28	10.14

Note: POV600 (600 meq·kg⁻¹ OFO diet), POV800 (800 meq·kg⁻¹ OFO diet), AP (POV600 group supplemented with 0.5% apple polyphenols), and TA (POV800 group supplemented with 0.2% taurine). ^aThese materials were provided by Nanchang Guanglian Industrial Co. Ltd. (Nanchang, Jiangxi, China). ^bPremix composition (mineral and vitamin, mg/kg diet): KCl 200; KI (1%), 60; CoCl₂ · 6H₂O, 50; FeSO₄·H₂O, 400; CuSO₄·5H₂O, 30; ZnSO₄·H₂O, 400; MnSO₄·H₂O, 150; Na₂SeO₃·5H₂O (1%), 65; MgSO₄·H₂O, 2000; zeolite power, 3645.85; VB1, 12; riboflavin, 12; VB6, 8; VB12, 0.05; VK3, 8; inositol, 100; pantothenic acid, 40; niacin acid, 50; folic acid, 5; biotin, 0.8; VA, 25; VD, 35; VE, 50; VC, 100; ethoxyquin, 150; wheat meal, 2434.15. These materials were provided by MGOTer Bio-Tech Co. Ltd. (Qingdao, Shandong, China). ^cMonocalcium phosphate was purchased from Chuanheng Ecological Technology Co., Ltd. (Shifang, Sichuan, China). ^dCholine chloride was purchased from Hebei Dazheng Feed Science & Technology Co., Ltd. (Cangzhou, Hebei, China). ^eEthoxyquin was purchased from Weifang Addeasy Bio-Technology Co., Ltd. (Weifang, Shandong, China). ^fCalcium propanoate was purchased from Shandong Jiutai Bio-Technology Co., Ltd. (Jinan, Shandong, China). ^gApple polyphenols (>80%) were purchased from JF-Natural Product R&D CO., Ltd. (Tianjin, China), and Taurine was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd. (Shanghai, China). ^hThe peroxide values (POVs) of the fish oil in the diets of the five groups were 9.5, 600, 600, 800, and 800 meq·kg⁻¹, respectively.