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Turkish towel (Chondracanthus exasperatus), Pacific dulse (Palmaria mollis, also known as Red ribbon seaweed), and sea lettuce (Ulva spp.) were cultivated in a land-based intensive culture system at the Manchester Research Station, USA from August 2013 to September 2014. Macroalgae were grown in tumble-aerated tanks, harvested bimonthly for seasonal growth calculations, and analyzed for protein, lipid, ash, and amino acid content. Growth rate of all three species exhibited a similar pattern, with the highest specific growth rates occurring during the summer months (Turkish towel: 7.8%, Pacific dulse: 8.2%, and sea lettuce: 6.2%). Growth of all three species was lowest around winter solstice; with negative growth only observed in sea lettuce. On a dry weight basis significant differences in protein content existed between the three species with highest values for sea lettuce (29.5 ± 1.4%). Lipid content varied between species (0.95-2.78%) with significantly higher lipid observed in sea lettuce (0.58-4.82%). No significant differences were detected on a seasonal basis among each species. Essential amino acids accounted for 43 ± 0.9 to 47 ± 1.2% of total amino acids with Turkish towel having the highest value. Turkish towel had a significantly higher taurine level (0.82 ± 0.27) than the other macroalgae. The levels of persistent organic pollutants and heavy metals were low. The estimated annual product of the three species ranged from 50-to 70-mt dry weight ha-1 y-1, significantly higher than conventional crops. Land-based culture of these species can produce year-round harvest, consistent product quality, and low contaminant levels. [ABSTRACT FROM AUTHOR]

It is possible to make feed ingredients of different by-products and this paper evaluates some of the important nutritional properties of Alaska pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus). Heads, viscera, frames, and skins were obtained from processing plants, and heads and viscera from plants processing pink salmon (Oncorhynchus gorbuscha). Essential amino acid concentrations were used for calculating rat protein efficiency ratio (PER) and resulted in high values for fillet, followed by whole fish, frames and viscera, heads and skin. All by-products except salmon viscera had greater than 90% pepsin digestibility. Differences in mineral content were detected between species within a by-product and between by-products within species. Percent soluble protein of pollock and salmon by-products increased as pH increased from 5.4 to 7.1. [ABSTRACT FROM AUTHOR]