Interest surrounding the use of macroalgae macromolecules for food products, biofuels, or other industrial applications is growing. As researchers search for macroalgae with especially high protein, lipid, carbohydrate or fibre content, the demand for a suite of standardized and unbiased methods for quantifying macroalgae macromolecules increases. Using data from available scientific literature, we evaluated the biases of the major methods used to determine macroalgal macromolecular content, as well as the sample drying methods employed. We found that drying at room temperature prior to analysis resulted in the highest estimates of protein and carbohydrate, and that freeze‐drying provided the highest estimates of lipid. Using nitrogen content and the standard conversion factor to calculate protein in macroalgae (N × 6.25 method) overestimates protein content compared to protein assays such as the Bradford () or Lowry () assays. The Bligh and Dyer () lipid extraction method was found to have a yield nearly two‐fold higher than other standard methods. For carbohydrates, the By Difference and Prosky et al. () methods provide estimates up to five‐fold higher than other common methods used to determine carbohydrate and fibre. Based on these results we recommend using protein assays as opposed to nitrogen content assays to determine protein content, the Bligh and Dyer lipid extraction method for lipids, and the By Difference and Prosky method for carbohydrate and fibre, respectively.
The objective of the current study was to determine whether prenatal iron deficiency induced during gestation in guinea pigs affected locomotor activity and learning and memory processes in the progeny. Dams were fed either iron-deficient anemic or iron-sufficient diets throughout gestation and lactation. After weaning, all pups were fed an iron-sufficient diet. On postnatal day 24 and 40, the pups’ locomotor activity was observed within an open-field test, and from postnatal day 25 to 40, their learning and memory processes were assessed within a Morris Water Maze. The behavioural and cognitive tests revealed that the iron deficient pup group had increased locomotor activity, but solely on postnatal day 40, and that there were no group differences in the Morris Water Maze. In the general discussion, we propose that prenatal iron deficiency induces an increase in nervousness due to anxiety in the progeny, which, in the current study, resulted in an increase of locomotor activity.
The macromolecular composition of macroalgae influences nutrient flow and food quality in aquatic ecosystems and the value of macroalgae species for human consumption, aquaculture, biofuels, and other applications. We used literature data (125 publications, 1,117 observations) and a hierarchal Bayesian statistical model to estimate the average macromolecular composition, protein, lipid, and carbohydrate of macroalgae as a whole and at the phylum level. Our focus was on marine, noncalcified macroalgae sampled from wild‐grown populations in the field. We found that the median macromolecular composition is 9.98% protein, 2.7% lipid, 48.5% carbohydrate, and 31.8% ash as percent dry weight. We compared the median macromolecular content of macroalgae to microalgae and herbaceous plants and test for differences in macromolecular content across macroalgal phyla. Macroalgae were much more enriched in carbohydrate and minerals than the microalgae and lower in protein and lipid than many herbaceous plants. Rhodophyte macroalgae have significantly less lipid and more protein and the Ochrophyte macroalgae have significantly less protein than the average.
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