Growth performance and muscle composition response to reduced feeding levels in juvenile red swamp crayfishProcambarus clarkii(Girard, 1852)

Abstract

Overfeeding in aquaculture can lead to suboptimal growth and increased production costs. Red swamp crayfish, Procambarus clarkii, is one of the most noteworthy species cultured in China, but little information is available on the optimal feeding levels of this species, especially in ponds cultured with macrophytes. In this study, we tested the effects of five different feeding levels (20%, 40%, 60%, 80% and 100% satiation) of an artificial diet on growth performance and muscle composition of juvenile P. clarkii in 15 concrete ponds cultured with the macrophyte Hydrilla verticillata (three replicates for each treatment). The results showed that growth performance decreased only when feeding levels were below 60% satiation. Muscle composition analysis revealed that the moisture and ash contents of muscle did not vary significantly with feeding levels but that the lipid and protein contents of muscle significantly decreased when P. clarkii was fed to 40% satiation. Stable isotope analysis suggested a shift in crayfish diets to easily available H. verticillata when feeding levels decreased. With this study, we hope to encourage crayfish farmers to reduce feeding levels and increase natural food items such as macrophytes in cultured ponds to maximize crayfish yields and reduce production costs.

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

“…Purslane weed ( P. oleracea ) seems to be a promising ingredient for inclusion in diets for intensive or semi‐intensive crayfish culture, or in new and more sustainable artificial feeds, given its added values in terms of carotenoids and polyunsaturated fatty acids that are easily converted in LC‐PUFA. From this perspective, it has been recently demonstrated that natural food items can save up to 25%–50% of the artificial feed, without affecting P. clarkii growth performance and muscle composition (Jin, Jacquin, Ren, et al, 2019). Further studies are needed to define the optimal percentages of P. oleracea inclusion in fishmeal‐based aquafeeds.…”

“…Fresh vegetables are rarely selected as primary foodstuff by crayfish, as their nutritional values are not appropriate for this species, in particular at the juvenile stage. However, this is an opportunistic species, shifting to a diet based on plant biomass when potential prey is scarce (Ilhéu & Bernardo, 1993) and the presence of plants in diet could potentially bring supplementary nutrition benefits to crayfish (Jin, Jacquin, Ren, et al, 2019). Vegetable species in crayfish extensive and semi-intensive aquaculture are considered important additional items apart from artificial feeds since they may constitute a relevant integration of P. clarkii diet, without affecting growth performance (Jin, Jacquin, Ren, et al, 2019).…”

“…Recent studies highlighted the need of refining feeding strategies of P. clarkii, limiting artificial diet amounts and considering the contribution of plant sources, which do not seem to reduce crayfish growth. P. clarkii in fact did not benefit from high feeding levels provided by commercial artificial diets (Jin, Jacquin, Ren, et al, 2019;Luo et al, 2021). Anyway, there are scanty experimental studies on whole vegetable diets improvement on juvenile crayfish quality.…”

Reduced dietary protein levels do not impair growth and muscle composition in juvenile red swamp crayfish,Procambarus clarkii(Girard, 1852): Implications for pond culture in China

“…Throughout the experiment, crayfish were fed twice daily (8:00 and 18:00). For each feeding practice, the experimental diets were put into a plastic pallet (30 × 15 cm), a diagram of which was described in our previous study (Jin et al, 2019). Crayfish were fed with an excess weighted diet.…”

“…They were then very finely ground into a homogeneous powder (<200 μm). All samples were then placed in a 3.5 × 5 mm tip cup for δ 15 N and δ 13 C isotope analysis (Jin et al, 2019). Specifically, 3-mg samples were combusted and the gases were analysed by gas chromatography and continuous flow-mass spectrometry (MAT-253, Thermo Fisher Scientific).…”