Valorization of Seaweed Wracks: Inclusion as Additive in Diets for Grass Carp (Ctenopharyngodon idella)

Table 1

Proximate composition (moisture, protein, ash, and total lipid content), total fatty acids, and main fatty acid composition of multispecific (MU) and monospecific (MO) wracks and diets used in the experiment.

	MU wrack	MO wrack	CD	CD + MU7	CD + MO7
Moisture (%)	—	—	12.89	10.22	12.49
Protein (% of DW)	—	—	35.63	34.25	35.20
Ash (% of DW)	—	—	7.30	10.49	10.09
Total lipid (% of DW)	2.51	3.49	9.19	8.92	9.28
Total FA (μg mg DW^-1)	—	—	70.95	71.71	75.16
Fatty acids (% of total FA)
Total SFA	47.18	39.34	24.00	23.79	23.76
14:0	6.09	7.83	2.23	2.29	2.28
16:0	36.31	28.17	16.16	16.03	15.97
18:0	2.00	1.00	4.11	4.01	4.03
Total MUFA	32.47	21.66	41.01	40.38	40.33
16:1^1	12.02	6.99	4.37	4.49	4.44
18:1^2	19.61	13.94	34.50	33.83	33.94
20:1^2	nd	nd	0.95	0.93	0.94
Total n-6 PUFA	8.66	19.93	22.48	22.32	22.31
18:2	2.79	9.73	21.38	21.35	21.35
20:4	4.23	7.31	0.70	0.74	0.74
Total n-3 PUFA	6.27	14.14	10.41	11.21	10.96
18:3	0.99	1.49	3.80	3.88	4.03
20:5	2.46	8.42	3.14	3.46	3.30
22:5	nd	nd	0.53	0.47	0.43
22:6	0.29	0.43	2.26	2.47	2.28
n-3/n-6	0.72	0.71	0.46	0.50	0.49
Total n-3 LC-PUFA	3.19	8.96	6.11	6.65	6.19

DW: dry weight; CD: control diet; CD + MU7: control diet supplemented with 7% multispecific macroalgal wrack; CD + MO7: control diet supplemented with 7% monospecific macroalgal wrack; FA: fatty acid; SFA: saturated fatty acids; MUFA: monounsaturated fatty acids; PUFA: polyunsaturated fatty acids; LC-PUFA: long-chain polyunsaturated fatty acids (≥C20 and ≥2 double bonds). Totals include other minor components not shown. ¹Mainly n-7 isomer for diets and n-9 for macroalgal wracks; ²mainly n-9 isomer. nd: not detected. Ingredients: corn gluten feed, wheat, processed animal proteins from poultry, soya meal feed, fish meal, and rapeseed oil.