Table 3.

In vivo studies incorporating seaweeds as anti-methanogenic agents in ruminants’ feed

Seaweeds	Animal	Basal diet	Dosage rates	Effect on CH4 emissions	References
Asparagopsis taxiformis	Brahman-Angus cross steers	Total mixed ration containing Rhodes grass hay, barley, grain/mineral/vitamin blend	4 dosage rates: 0, 0.05%, 0.10%, and 0.2% of total feed organic matter	0.1% and 0.2% dosage rates reduced CH4 emissions by 40% and 92%, respectively	[36]
Asparagopsis taxiformis	Merino-cross wethers sheep	Commercial pelleted ration containing high fibre diet (< 2% organic matter)	5 dosage rates: 0, 0.5%, 1%, 2%, and 3% on organic matter basis	3% dosage rate decreased CH4 emissions by 80% compared to control	[95]
Asparagopsis armata	One Jersey and one Holstein	Total mixed ration	3 dosage rates: 0, 0.5%, and 1% on organic matter basis	0.5% inclusion rate decreased CH4 emission by 26.4% 1% inclusion rate decreased CH4 emission by 67.2%	[15]
Asparagopsis taxiformis	Angus-Hereford beef steers	3 diets fed over time to achieve low forage total mixed ration diet: - Starter diet (63 d) high forage diet - Transition diet (21 d) medium forage - Finisher diet (63 d) Forage contained varying proportions of alfalfa hay, wheat hay, dry distiller grain, and concentrates	3 dosage rates: 0, 0.25%, and 0.5% on organic matter intake basis	Low forage total mixed ration diet supplemented with 0.25% A. taxiformis reduced CH4 by 69.8% Low forage total mixed ration diet supplemented with 0.5% A. taxiformis reduced CH4 by 80%	[94]
Asparagopsis taxiformis	Lactating Holstein cows	Total mixed ration	3 dosage rates: 0, 0.25%, and 0.5% on dry matter basis	0.5% A. taxiformis decreased CH4 emission by 65%	[16]