@article {7896, title = {The onset of piscivory in a freshwater fish species: analysis of behavioural and physiological traits}, journal = {Journal of Fish Biology}, volume = {96}, year = {2020}, month = {Jan-06-2020}, pages = {1463 - 1474}, abstract = {The onset of piscivory in fish, resulting in a shift from zooplankton or invertebrate to fish prey, was studied on pikeperch (Sander lucioperca) larvae displaying and not dis- playing piscivorous behaviour at different ages (23, 30, 37, 44 and 52 days post- hatching) using behavioural (attack, capture and swimming activity), morphological (allometry) and digestive enzymatic (trypsin,\ α-amylase and pepsin) analyses. The shift from zooplanktonic food items (Artemia\ nauplii) to a piscivorous diet did not occur at the same time for all individuals within the same cohort. Predation tests, conducted under controlled conditions (20C;\ ad libitum\ feeding), showed that some larvae attacked fish prey as early as the age of 3 weeks [11.0 {\textpm} 1.3 mm total length (TL)], whereas others did not start until the age of 6 weeks (16.6 {\textpm} 1.9 mm TL). Piscivorous individuals were bigger, with larger heads, longer tails, higher acid protease and lower alkaline protease activities, than non-piscivorous conspecifics. In conclusion, high interindividual variability in morphological and digestive system developments linked to the development of predatory abilities could induce cannibalism in fish.}, keywords = {behavioural tests, early life stages, freshwater fish, predatory behaviour, Sander lucioperca}, issn = {0022-1112}, doi = {10.1111/jfb.v96.610.1111/jfb.14322}, url = {https://onlinelibrary.wiley.com/toc/10958649/96/6}, author = {Tatiana Colchen and Dias, Andr{\'e}a and Gisbert, Enric and Teletchea, Fabrice and Fontaine, Pascal and Pasquet, Alain} } @article {5499, title = {Dietary aquaculture by-product hydrolysates: impact on the transcriptomic response of the intestinal mucosa of European seabass (Dicentrarchus labrax) fed low fish meal diets}, journal = {BMC Genomics}, volume = {19}, year = {2018}, abstract = {

Aquaculture production is expected to double by 2030, and demands for aquafeeds and raw materials are expected to increase accordingly. Sustainable growth of aquaculture will require the development of highly nutritive and functional raw materials to efficiently replace fish meal. Enzymatic hydrolysis of marine and aquaculture raw materials could bring new functionalities to finished products. The aim of this study was to determine the zootechnical and transcriptomic performances of protein hydrolysates of different origins (tilapia, shrimp, and a combination of the two) in European seabass (Dicentrarchux labrax) fed a low fish meal diet (5\%), for 65\ days.

Results

Results were compared to a positive control fed with 20\% of fish meal. Growth performances, anterior intestine histological organization and transcriptomic responses were monitored and analyzed. Dietary inclusion of protein hydrolysates in the low fish meal diet restored similar growth performances to those of the positive control. Inclusion of dietary shrimp hydrolysate resulted in larger villi and more goblet cells, even better than the positive control. Transcriptomic analysis of the anterior intestine showed that dietary hydrolysate inclusion restored a pattern of intestinal gene expression very close to the pattern of the positive control. However, as compared to the low fish meal diet and depending on their origin, the different hydrolysates did not modulate metabolic pathways in the same way. Dietary shrimp hydrolysate inclusion modulated more metabolic pathways related to immunity, while nutritional metabolism was more impacted by dietary tilapia hydrolysate. Interestingly, the combination of the two hydrolysates enhanced the benefits of hydrolysate inclusion in diets: more genes and metabolic pathways were regulated by the combined hydrolysates than by each hydrolysate tested independently.

Conclusions

Protein hydrolysates manufactured from aquaculture by-products are promising candidates to help replace fish meal in aquaculture feeds without disrupting animal metabolism and performances.

}, keywords = {Aquaculture, Aquafeed, By-products, European seabass, Fishmeal replacement, Hydrolysate, Illumina RNA-sequencing, Intestinal organization, Metabolic pathways}, doi = {doi.org/10.1186/s12864-018-4780-0}, author = {Leduc, Alexandre and C{\'e}line Zatylny-Gaudin and Robert, Marie and Corre, Erwan and Le Corguill{\'e}, Gildas and Castel, H{\'e}l{\`e}ne and Lefevre-Scelles, Antoine and Fournier, Vincent and Gisbert, Enric and Andree, Karl B. and Jo{\"e}l Henry} }