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Factors determining the degree of dietary generalism versus specialism are central in ecology. Species that are generalists at the population level may in fact be composed of specialized individuals. The optimal diet theory assumes that individuals choose diets that maximize fitness, and individual specialization may occur if individuals' ability to locate, recognize, and handle different food types differ. We investigate if individuals of the marine herbivorous slug Elysia viridis, which co-occur at different densities on several green macroalgal species in the field, are specialized to different algal hosts. Individual slugs were collected from three original algal host species (Cladophora sericea, Cladophora rupestris and Codium fragile) in the field, and short-term habitat choice and consumption, as well as long-term growth (proxy for fitness), on four algal diet species (the original algal host species and Chaetomorpha melagonium) were studied in laboratory experiments. Nutritional (protein, nitrogen, and carbon content) and morphological (dry weight, and cell/utricle volume) algal traits were also measured to investigate if they correlated with the growth value of the different algal diets. E. viridis individuals tended to choose and consume algal species that were similar to their original algal host. Long-term growth of E. viridis, however, was mostly independent of original algal host, as all individuals reached a larger size on the non-host C. melagonium. E. viridis growth was positively correlated to algal cell/utricle volume but not to any of the other measured algal traits. Because E. viridis feeds by piercing individual algal cells, the results indicate that slugs may receive more cytoplasm, and thus more energy per unit time, on algal species with large cells/utricles. We conclude that E. viridis individuals are specialized on different hosts, but host choice in natural E. viridis populations is not determined by the energetic value of seaweed diets as predicted by the ODT.

Comminuted meat products represent a diverse class of meat products that are popular for their characteristic texture and flavor. Comminuted meat products are incorporated with dietary fibers for various functional and nutritional purposes. These fibers are mostly the carbohydrate polymers of different types. The dietary fibers have been observed to affect the texture of meat products irrespective of the reason for their incorporation. These fibers have been shown to enhance the functional properties and health benefits of meat products. The effect of different fibers on the textural and other quality attributes has not been reported uniformly by the researchers making it hard to compare these studies. In this review, we have given an overview of the textural properties of comminuted meat products and summarized the existing researches reported on the textural changes of meat products due to soluble dietary fiber incorporation.

Obtaining eggs and larvae in large quantities is a critical point for the economic viability of sea cucumber aquaculture. In this paper, spawning induction methods and in-vitro fertilisation (IVF) methods are presented and compared. The IVF technique developed in Madagascar (MH-IVF) is a simple, cost-efficient method that enables hatcheries to obtain clean, fertilised eggs of sea cucumbers year-round. MH-IVF does not require high-tech equipment and is applicable in small- and large-scale hatcheries. It ensures the best control at the very beginning of the work on the number and type of genitors (i.e. sex, length, weight, colour); the quality of the gonads (healthy versus parasitised); and the number, size and quality of spermatozoa and eggs. MH-IVF involves the sacrifice of very few genitors compared with the individuals obtained and sacrificed for production. Yet, it does not influence genetic drift any more than spawning induction methods.

Chondracanthus chamissoiis a red algawhich is acquiring an increasing economic impor-tance in Chile and becoming a target species forcultivation. Because epiphytism is a major problem inthe mariculture of seaweeds, the recruitment ofUlvasp. andEnteromorphasp. on gametophytic (cysto-carpic) and tetrasporophytic thalli ofC. chamissoiwas testedin vitroon four populations from differentlocations in Chile. ForUlvasp., the density, cover andlength of the recruits varied between the reproductivephases of the host and among the studied populationsofC. chamissoi. In most experiments, a larger numberof epiphytic thalli was observed on gametophyticplants ofC. chamissoi; populations from Calderillaand Lechagua had a higher resistance to epiphytism.ForEnteromorphasp., its ability to grow epiphyti-cally on both phases of the host showed a greatervariability, but was inferior to that ofUlvasp. Thedifferential resistance to epiphytism in both reproduc-tive phases and in plant origin indicates the possibilityof obtaining selected strains ofC. chamissoiwithlower susceptibility to epiphytism that could beutilized in planning maricultural programs.