Feeding Preferences and the Nutritional Value of Tropical Algae for the Abalone Haliotis asinina

Understanding the feeding preferences of abalone (high-value marine herbivores) is integral to new species development in aquaculture because of the expected link between preference and performance. Performance relates directly to the nutritional value of algae – or any feedstock – which in turn is driven by the amino acid content and profile, and specifically the content of the limiting essential amino acids. However, the relationship between feeding preferences, consumption and amino acid content of algae have rarely been simultaneously investigated for abalone, and never for the emerging target species Haliotis asinina. Here we found that the tropical H. asinina had strong and consistent preferences for the red alga Hypnea pannosa and the green alga Ulva flexuosa, but no overarching relationship between protein content (sum of amino acids) and preference existed. For example, preferred Hypnea and Ulva had distinctly different protein contents (12.64 vs. 2.99 g 100 g−1) and the protein-rich Asparagopsis taxiformis (>15 g 100 g−1 of dry weight) was one of the least preferred algae. The limiting amino acid in all algae was methionine, followed by histidine or lysine. Furthermore we demonstrated that preferences can largely be removed using carrageenan as a binder for dried alga, most likely acting as a feeding attractant or stimulant. The apparent decoupling between feeding preference and algal nutritive values may be due to a trade off between nutritive values and grazing deterrence associated with physical and chemical properties

Diagnosis and management of Cornelia de Lange syndrome:first international consensus statement

Cornelia de Lange syndrome (CdLS) is an archetypical genetic syndrome that is characterized by intellectual disability, well-defined facial features, upper limb anomalies and atypical growth, among numerous other signs and symptoms. It is caused by variants in any one of seven genes, all of which have a structural or regulatory function in the cohesin complex. Although recent advances in next-generation sequencing have improved molecular diagnostics, marked heterogeneity exists in clinical and molecular diagnostic approaches and care practices worldwide. Here, we outline a series of recommendations that document the consensus of a group of international experts on clinical diagnostic criteria, both for classic CdLS and non-classic CdLS phenotypes, molecular investigations, long-term management and care planning

Seaweed as a protein source for mono-gastric livestock

Background: Seaweeds are often cited as alternative protein sources for livestock due to their global distribution, nutritional profile and independence from terrestrial agricultural resources. Scope and approach: Here, we critically appraise the literature and quantitatively assess seaweeds as a protein source in livestock feeds by assembling a database of amino acid data for 121 seaweed species and comparing the quality and concentration of protein to 'traditional' protein sources (soybean meal and fishmeal) and then benchmarking the seaweeds against the amino acid requirements of mono gastric livestock (chicken, swine and fish). Key findings and conclusions: The quality of protein (% of essential amino acids in total amino acids) of many seaweeds is similar to, if not better than, traditional protein sources. However, seaweeds without exception have substantially lower concentrations of total essential amino acids, methionine and lysine (on a whole biomass basis, % dw) than traditional protein sources. Correspondingly, seaweeds contain an insufficient concentration of protein, and specifically insufficient essential amino acids, to meet the requirements of most mono-gastric livestock in the whole seaweed form. Consequently, the concentration or extraction of protein from seaweeds will be the most important goal in their development as an alternative source of protein for mono-gastric livestock

Seaweed as a protein source for mono-gastric livestock

Background: Seaweeds are often cited as alternative protein sources for livestock due to their global distribution, nutritional profile and independence from terrestrial agricultural resources. Scope and approach: Here, we critically appraise the literature and quantitatively assess seaweeds as a protein source in livestock feeds by assembling a database of amino acid data for 121 seaweed species and comparing the quality and concentration of protein to 'traditional' protein sources (soybean meal and fishmeal) and then benchmarking the seaweeds against the amino acid requirements of mono gastric livestock (chicken, swine and fish). Key findings and conclusions: The quality of protein (% of essential amino acids in total amino acids) of many seaweeds is similar to, if not better than, traditional protein sources. However, seaweeds without exception have substantially lower concentrations of total essential amino acids, methionine and lysine (on a whole biomass basis, % dw) than traditional protein sources. Correspondingly, seaweeds contain an insufficient concentration of protein, and specifically insufficient essential amino acids, to meet the requirements of most mono-gastric livestock in the whole seaweed form. Consequently, the concentration or extraction of protein from seaweeds will be the most important goal in their development as an alternative source of protein for mono-gastric livestock

A comparison of protocols for isolating and concentrating protein from the green seaweed Ulva ohnoi

We compared protocols to isolate and concentrate protein from the green seaweed Ulva ohnoi. We quantified the effect of three factors on protein and essential amino acid yields and concentrations in protein isolates and residuals in a factorial experimental design. The three factors were starting material (as dry and milled or fresh and pulped), aqueous solvent-to-biomass ratio (20:1 or 5:1 v/w) and the incubation time in the aqueous solvent (incubated for 16 h at 30 A degrees C or incubated for < 1 min at ambient temperature). The protein isolation protocols increased the concentration of protein, total essential amino acids, methionine and lysine similar to 3 to 5-fold compared to whole U. ohnoi and were considerably more effective than the different protein concentrating combinations, which only increased protein and amino acid concentrations by 30-40 % in the residual biomass. The use of fresh and pulped biomass as the starting material, an incubation time of < 1 min at ambient temperature and a low aqueous solution volume resulted in the highest protein isolate yield of 22 % of the protein found in seaweed. This study demonstrated that proteins from U. ohnoi were most effectively isolated by adopting protocols for terrestrial leaves compared to the protocols employed for seed crops as traditionally applied to seaweeds

Indirect and direct effects of salinity on the quantity and quality of total amino acids in Ulva ohnoi (Chlorophyta)

Salinity can affect the quantity and quality of total amino acids (TAAs) in seaweeds indirectly by altering growth rates and thereby diluting or concentrating the amino acid content of the biomass, or directly by altering the synthesis of specific amino acids and osmolytes. This study attempted to partition the indirect and direct effects of salinity on the quantity and quality of TAAs in the green seaweed Ulva ohnoi by culturing it under a range of salinities without nutrient limitation. Both the quantity and quality of TAAs varied across the salinity treatments. Quantity was most strongly related to the growth rate of the seaweed and was highest in the slowest growing seaweed. In contrast, the quality of TAAs (individual amino acids as a proportion of total content) was most strongly related to salinity for all amino acids, although this varied substantially among individual amino acids. Increases in salinity were positively correlated with the proportion of proline (46% increase), tyrosine (36% increase), and histidine (26% increase), whereas there was a negative correlation with alanine (29% decrease). The proportion of methionine, with strong links to the synthesis of the osmolyte dimethylsulfoniopropionate, did not correlate linearly with salinity and instead was moderately higher at the optimal salinities for growth. These results show that salinity simultaneously affects the quantity and quality of TAAs in seaweed through both indirect and direct mechanisms, with growth rates playing the overarching role in determining the quantity of TAAs

The protein content of seaweeds: a universal nitrogen-to-protein conversion factor of five

A global drive to source additional and sustainable biomass for the production of protein has resulted in a renewed interest in the protein content of seaweeds. However, to determine accurately the potential of seaweeds as a source of protein requires reliable quantitative methods. This article systematically analysed the literature to assess the approaches and methods of protein determination and to provide an evidence-based conversion factor for nitrogen to protein that is specific to seaweeds. Almost 95 % of studies on seaweeds determined protein either by direct extraction procedures (42 % of all studies) or by applying an indirect nitrogen-to-protein conversion factor of 6.25 (52 % of all studies), with the latter as the most widely used method in the last 6 years. Meta-analysis of the true protein content, defined as the sum of the proteomic amino acids, demonstrated that direct extraction procedures underestimated protein content by 33 %, while the most commonly used indirect nitrogen-to-protein conversion factor of 6.25 over-estimated protein content by 43 %. We therefore determined whether a single nitrogen-to-protein conversion factor could be used for seaweeds and evaluated how robust this would be by analysing the variation in this factor for 103 species across 44 studies that span three phyla, multiple geographic regions and a range of nitrogen contents. An overall median nitrogen-to-protein conversion factor of 4.97 was established and an overall mean nitrogen-to-protein conversion factor of 4.76. We propose that the overall median value of 5 be used as the most accurate universal seaweed nitrogen-to-protein (SNP) conversion factor

Cyclical changes in biomass productivity and amino acid content of freshwater macroalgae following nitrogen manipulation

The effective supply of nitrogen to algal cultures is an important aspect of intensive cultivation and critical if the biomass is to be used as a source of protein. In this study two complementary experiments examine how variation in the supply of nitrogen to cultures influenced the biomass productivity and protein content of the freshwater macroalga, Oedogonium. The first examined how robust Oedogonium is to the intermittent supply of nitrogen (supplied weekly, every second week or every third week) by quantifying its biomass productivity, photosynthetic capacity and internal nitrogen content through time. Biomass productivity over a 12-week period was highest (10.6 g DW m− 2 day− 1) when nitrogen was supplied weekly and lowest (8.1 g DW m− 2 day− 1) when nitrogen was supplied every third week. The second experiment examined the recovery of nitrogen and amino acids in the biomass following periods of nitrogen-depletion. Prolonged periods (2 weeks) without nitrogen reduced the internal nitrogen and amino acid content of the biomass by up to 80%. However, in all treatments the internal nitrogen content recovered within 24–48 h and the amino acid content had recovered within 72 h following the resupply of external nitrogen. These results demonstrate that nitrogen should be supplied in a relatively constant manner to maximize the growth rates of Oedogonium; however, the protein in nitrogen-deplete cultures can be rapidly rejuvenated by the addition of nitrogen in the days prior to harvest

Feeding preferences of <i>H. asinina</i> in two separate multiple choice feeding assays (A & B).

<p>Data show mean (+SE) consumption rates of each species (g FW algae day⁻¹) for red, brown and green algae standardised for abalone size (100g⁻¹ BW). <b>A</b>. Preferences between 6 algal species (n = 11) with abalone size range of 35–80 g (mean = 54.26 g). <b>B</b>. Preferences between 5 algal species (n = 19) with a larger abalone size range; 29–184 g (mean = 95.63 g). Common letters above columns indicate no significant difference in preference between treatments for each assay (Friedman’s multiple comparisons, p>0.05).</p

No-choice feeding assay of artificial diets comprised of dried algae and bound by carrageenan.

<p>Data show mean (+SE) consumption rates (g FW diet day⁻¹, n = 5) of diets per treatment standardised for abalone size (100g⁻¹ BW). Abalone size ranged from 26–184 g (mean = 89.63 g). Common letters above columns indicate no significant difference (Tukey’s HSD, p>0.05). Control diet (white bar, no algae) was also included in the formal analysis.</p