The pattern of yellowish pigmentation of the skin was assessed in gilthead seabream (Sparus aurata) fed for 12 weeks iso-proteic (45%) and iso-lipidic (20%) diets deprived of fish meal and containing either a blend of vegetable protein-rich ingredients or where graded levels of the vegetable protein blend were replaced by insect (Hermetia illucens—10%, 20% or 40%) pupae meal, poultry by-product meal (20%, 30% or 40%), red swamp crayfish meal (10%) and marine microalgae (Tisochrysis lutea and Tetraselmis suecica—10%) dried biomass. Digital images of fish fed diets differing in protein sources were analyzed by means of an automatic and non-invasive image analysis tool, in order to determine the number of yellow pixels and their dispersion on the frontal and lateral sides of the fish. The relationship between the total carotenoid concentration in the diet and the number of yellow pixels was investigated. Test diets differently affected gilthead seabream skin pigmentation both in the forefront and the operculum, due to their carotenoid content. The highest yellow pixels’ number was observed with the diet containing microalgae. Fish fed poultry by-product meal were characterized by the lowest yellow pixels’ number, diets containing insect meal had an intermediate coloring capacity. The vegetable control, the microalgae mix diet and the crayfish diet had significantly higher values of yellow pixels at both inspected skin sites.

The extraordinary polymorphism of major histocompatibility complex (MHC) genes is considered a paradigm of pathogen‐mediated balancing selection, although empirical evidence is still scarce. Furthermore, the relative contribution of balancing selection to shape MHC population structure and diversity, compared to that of neutral forces, as well as its interaction with other evolutionary processes such as hybridization, remains largely unclear. To investigate these issues, we analyzed adaptive (MHC‐DAB gene) and neutral (11 microsatellite loci) variation in 156 brown trout (Salmo trutta complex) from six wild populations in central Italy exposed to introgression from domestic hatchery lineages (assessed with the LDH gene). MHC diversity and structuring correlated with those at microsatellites, indicating the substantial role of neutral forces. However, individuals carrying locally rare MHC alleles/supertypes were in better body condition (a proxy of individual fitness/parasite load) regardless of the zygosity status and degree of sequence dissimilarity of MHC, hence supporting balancing selection under rare allele advantage, but not heterozygote advantage or divergent allele advantage. The association between specific MHC supertypes and body condition confirmed in part this finding. Across populations, MHC allelic richness increased with increasing admixture between native and domestic lineages, indicating introgression as a source of MHC variation. Furthermore, introgression across populations appeared more pronounced for MHC than microsatellites, possibly because initially rare MHC variants are expected to introgress more readily under rare allele advantage. Providing evidence for the complex interplay among neutral evolutionary forces, balancing selection, and human‐mediated introgression in shaping the pattern of MHC (functional) variation, our findings contribute to a deeper understanding of the evolution of MHC genes in wild populations exposed to anthropogenic disturbance.

Italy supplies approximately 96% of EU-farmed Manila clams. Following a reduction in wild seed availability, farmers started to depend on hatchery-produced seed, mainly imported from other countries. Indeed, only one hatchery is currently operating in Italy. This study quantifies the environmental impacts of seed production in this Italian hatchery facility to inform future planning for improving the sustainability of the supply chain. The environmental performance of the Manila clam hatchery was evaluated using the Life Cycle Assessment methodology. A cradle-to-gate analysis was performed, covering the following production phases: (1) microalgae production, (2) broodstock maintenance and conditioning, and (3) larval rearing until marketable size. The functional unit adopted was 1 kg of live clam seed. The main driver of the environmental impacts was electricity consumption, contributing over 80% for all impact categories. Other inputs showed minor contributions to different impact categories, including liquid oxygen, water pumps, and high-density polyethylene. This study highlights that the environmental burden associated with seed production could be reduced by switching to alternative technologies to meet energy needs, such as investments in photovoltaic and wind energy production systems.

Sturgeon farming poses an interesting decision: give priority to highly prized caviar or meat. Indeed, sturgeons are mainly reared in aquaculture to produce caviar. However, the economic profitability of a sturgeon farm also depends on the existence of a meat market. Meat is still an important product for sturgeon farmers once the stock of caviar-producing females has been established. This paper takes a case study approach and analyses how an Italian producer addresses the trade-off, adopting a methodology that measures the value of the economic productivity of production inputs, e.g., the measure of the profitability of the inputs, and compares them with the costs of the inputs and the prices of the outputs. This analysis is the first attempt, to our knowledge, to adopt an economic analysis to address this choice problem, based on a very representative case study. This helps monitor whether the farm’s production choices are economically efficient and effective and whether and how those can be improved. The results show that the farm maximizes profit but does not reach its optimal production level. This implies that both (1) producing more output and (2) a further switch to caviar production for less meat are economically efficient production strategies.

The house cricket (Acheta domesticus) is considered one of the most promising farmed insect to be used as novel food, thanks to its attractive nutritional profile and its great taste. To the best of our knowledge, crickets in Europe are reared on soybean meal-rich feed which won’t be sustainable in the long run. Insect producers have shown interest in using more environmentally friendly substrates for cricket’s rearing. Among these, seaweed has been investigated as feed ingredients for insect rearing. However, no studies on crickets are available. We aimed to evaluate the potential use of the alga Palmaria palmata in the diet of house crickets (5%, 10% and 20% of the diet), in terms of insect performances and nutritional composition (protein, lipid, amino acids and fatty acids). Crickets fed seaweed-enriched diets showed good performance parameters (individual weight, cricket yield and survival) compared to crickets fed the control diet without presenting statistically significant differences (), while their nutritional composition changed significantly for some components. Protein content of the crickets increased when more seaweed was added to their diets (), while the fat content decreased (). Also, the amino acid composition of the crickets remained stable between dietary groups, except for histidine, methionine and lysine which increased in crickets fed more seaweed in the diet (, , , respectively). Finally, the presence of seaweed in the diet led to a transfer of the omega-3 eicosapentaenoic acid from the seaweed to the crickets (), which are naturally lacking this fatty acid. Based on this study, we conclude that the red alga Palmaria Palmata is a suitable substrate for cricket mass rearing up to 20 g/100 g of the diet. However, higher seaweed inclusion and longer dietary administration time could affect the nutritional composition of the house cricket differently, therefore they should be investigated.

A 10-week feeding trial was carried out to emphasize the effects of purslane weed (Portulaca oleracea) whole diet on pigmentation and fatty acids profile of juvenile freshwater red swamp crayfish Procambarus clarkii. Purslane weed is an annual succulent herb easily found in tropical and temperate regions showing a high-quality PUFA profile and carotenoid content. Crayfish fed with P. oleracea were compared with two groups fed with aquatic macrophytes control diets. At the end of the experiment, each group showed a distinct fatty acid composition, with crayfish feeding P. oleracea that exhibited significantly higher n-3 PUFA content (1.01 mg × 100 g⁻¹) and total carotenoids (mainly astaxanthin) concentration (72.2 mg × kg⁻¹). In natural conditions, plants are not used as primary foodstuff by crayfish, but in extensive and semi-intensive aquaculture, they could bring supplementary nutrition benefits to crayfish without affecting growth performance. P. oleracea could represent a promising ingredient in crayfish diets, or in new artificial feeds, given its added values in terms of carotenoids and polyunsaturated fatty acids. The results of this study might encourage further research aimed at defining the optimal percentages of P. oleracea inclusion in sustainable crayfish diets.