Effects ofPortulaca oleraceawhole diet on pigments and fatty acids profiles of juvenile red swamp crayfish (Procambarus clarkiiGirard, 1852) under laboratory conditions

Abstract

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.

Reduced protein intake in Procambarus clarkii fed diets containing graded levels of purslane: Effects on growth and quality

“…In general, all levels of inclusion of P. oleracea in crayfish experimental diets showed several positive effects on all the parameters investigated, except in the case of a purslane diet alone (i.e., Pweed 100%). An entire plant diet, as expected and previously reported (Martinoli et al, 2021), showed the lowest nutritional value, most likely due to the low protein content for this species. Moreover, the potential accumulation of oxalic acid in crayfish fed only with purslane might have negatively affected growth performances (Gemede & Ratta, 2014; Nemzer et al, 2020).…”

“…The high levels of these PUFAs found in all the experimental groups confirmed that P. clarkii can store these components gained from food. As with PUFAs, carotenoid and astaxanthin content also come from food (Bjerkeng, 2000; Martinoli et al, 2021).…”

“…Before the feeding trials started, 10 juvenile crayfish were randomly designated as the T0 group, painlessly sacrificed by immersion in ice, and analyzed. The remaining 144 crayfish were acclimatized for 5 days in indoor tanks and then divided into six triplicate treatment groups of eight individuals each, to be reared according to Trimble and Gaudé (1988) with adjustments (Martinoli et al, 2021). The experimental setup consisted of a single recirculating aquaculture system, composed of six glass tanks (100 × 50 × 60 cm); each tank was sub‐divided by PVC panels into three compartments (replicas), resulting in a total of 18 aquariums of about 40 L each, placed within a 6 m 2 room without external light sources.…”

“…P. oleracea has been recently studied as a new ingredient in fish and crustacean diets (Martinoli et al, 2021; Şahin et al, 2021), especially for its desirable functional properties related to pigmentation, antistress, and antioxidant effects (Gould et al, 2019; Santiago‐Saenz et al, 2018). Some studies have reported the presence of antinutritional factors, such as oxalic acid, in purslane and other plant ingredients if consumed in large quantities (Gemede & Ratta, 2014; Xiao et al, 2014).…”

“…Some studies have reported the presence of antinutritional factors, such as oxalic acid, in purslane and other plant ingredients if consumed in large quantities (Gemede & Ratta, 2014; Xiao et al, 2014). Crayfish fed P. oleracea showed high concentrations of carotenoids (astaxanthin) and short‐chain polyunsaturated fatty acids (SC‐PUFAs) which are easily converted in to long‐chain PUFAs (LC‐PUFAs) (Martinoli et al, 2021). In tiger shrimps, P. oleracea ‐based diet accelerated the molting, promoting faster growth and higher survival rates (Rosmiati et al, 2016).…”