Table 2.

Chemical composition (g/kg dry matter unless otherwise stated) of different seaweed species harvested in spring and autumn in northern Norway and of feeds commonly used in ruminant diets.

Species	Season	Dry Matter	Ash	Nitrogen	Total Extractable Polyphenols
		(g/100 g Fresh Matter)
Brown seaweeds
Alaria esculenta	Spring	110	288	23.4	4.51
	Autumn	277	73.6	13.1	28.1
	Average	193 f	181 d	18.2 d	16.3 e
Laminaria digitata	Spring	115	311	23.0	1.44
	Autumn	189	138	6.77	6.08
	Average	152 b	225 e	14.9 c	3.76 d
Pelvetia canaliculata	Spring	237	199	16.3	26.9
	Autumn	237	174	6.88	40.4
	Average	237 g	187 d	11.6 a	33.7 f
Saccharina latissima	Spring	87.0	350	17.6	3.87
	Autumn	220	100	6.03	5.21
	Average	154 c	225 e	11.8 a	4.54 d
Red seaweeds
Mastocarpus stellatus	Spring	261	183	26.4	4.36
	Autumn	245	194	18.1	3.57
	Average	253 h	189 d	22.2 e	3.97 ab
Palmaria palmata	Spring	121	213	43.0	3.86
	Autumn	191	103	14.6	1.93
	Average	156 d	158 c	28.8 f	2.89 b
Porphyra sp.	Spring	90.0	97.9	59.8	4.75
	Autumn	116	78.4	50.9	5.85
	Average	103 a	88.2 a	55.4 h	5.30 c
Green seaweeds
Cladophora rupestris	Spring	191	149	37.1	4.88
	Autumn	181	105	37.0	5.39
	Average	186 e	127 b	37.1 g	5.14 bc
p value
Species		<0.001	<0.001	<0.001	<0.001
Season		<0.001	<0.001	<0.001	<0.001
SEM		0.004	0.670	0.128	0.035
Feeds
Oat hay		896	62.7	12.7	6.82
Barley straw		941	43.7	3.07	NA 1
Commercial concentrate		933	77.4	23.0	NA 1

^a–e For each parameter, average values for each seaweed not sharing the same superscript differ (p < 0.001); ¹ NA: not analysed.