Effects of Different Diet Types on Growth and Survival of White-Clawed Crayfish Austropotamobius pallipes in Hatcheries

Abstract

Developing an optimal diet for rearing endangered white-clawed crayfish Austropotamobius pallipes is important for captive breeding success prior to wild release. Four ex situ, 40-day experiments assessed survival and growth of crayfish fed different treatment diets. Two experiments (A and B) were undertaken with hatchlings, to determine if live food was an essential dietary component during the first few weeks after hatching. The second set of experiments (C and D) were undertaken with juvenile (60-day-old) A. pallipes, to determine an optimal diet after the initial critical feeding stage. In experiment A, we fed hatchlings: i) live Artemia nauplii + plankton (Live + P); ii) decapsulated Artemia cysts + plankton (Cyst + P) or iii) decapsulated Artemia cysts + plankton encapsulated in agar gel (Gel + CP). Survival and growth was significantly greater with Live + P than with the other two diets. In experiment B we compared Live + P with commercially available feeds by feeding hatchlings: i) live Artemia nauplii + Australian pellet (Live + Aus); ii) live Artemia nauplii plus New Zealand pellet (Live + NZ); iii) live Artemia nauplii + plankton (Live + P); or (iv) practical Spanish crayfish pellet diet (Spain). Under these experimental conditions crayfish survival was significantly higher with Live + P diet than with Live + Aus or Spain. Growth was also significantly greater with Live + P than with the Live + NZ or Spanish treatment diets. In experiment C, 60-day-old juvenile A. pallipes were fed: i) defrosted plankton plus vegetables (Standard) or (ii) defrosted plankton plus vegetables encapsulated in agar gel (Gel + PV). Survival was not significantly different between the diets; however, growth was significantly greater with the Standard diet rather than Gel + PV. In experiment D, juveniles were fed four different diets: i) Australian pellet (Australia); ii) New Zealand pellet (New Zealand); iii) plankton and vegetables (Standard); or iv) practical Spanish diet (Spain). Survival was significantly lower in crayfish fed the New Zealand diet. Crayfish growth was significantly greater with the Standard diet of plankton and vegetables than all three pellet diets. Our results showed that live food is optimal for high survival and growth in A. pallipes hatchlings and a plankton, plus vegetable, diet produces higher growth in juveniles compared to pellet diets.

Aquaculture indicators of young Cherax Quadricarinatus under various feeding plans

“…Currently, Ukraine does not have a sufficient selection of high-quality and balanced fodder for feeding young Australian red-clawed crayfish. Manufacturers of commercial feed in most cases do not want to disclose its composition and nutritional value (Nightingale et al, 2021). Therefore, the obtained data are consistent with the results (Méndez-Martínez et al, 2021), which used feed based on protein components of plant-based protein components, obtained better results than when feeding conventional vegetable feed.…”

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“…Currently, Ukraine does not have a sufficient selection of high-quality and balanced fodder for feeding young Australian red-clawed crayfish. Manufacturers of commercial feed in most cases do not want to disclose its composition and nutritional value (Nightingale et al, 2021). Therefore, the obtained data are consistent with the results (Méndez-Martínez et al, 2021), which used feed based on protein components of plant-based protein components, obtained better results than when feeding conventional vegetable feed.…”

Natural Biota’s Contribution to Cultured Aquatic Animals’ Growth in Aquaculture Cannot Be Ignored

“…In semiintensive or intensive culture, juveniles exhibit a preference for feeding on natural biota over formulated feeds [145], and they derive a substantial part of their dietary nutrients from natural biota. Tey could promote better survival and growth of cultured aquatic animals compared with artifcial diets alone [18,125]. For example, the early (0.10 ± 0.05 g) and advanced juveniles (0.98 ± 0.43 g) of Cherax quadricarinatus fed on bioflm (Chlorophyta, xantophytas, pennate diatoms, cyanobacteria, fagellates, ciliates, rotifers, and nematodes) and formulated feed showed better survival, growth performance, and hepatopancreatic levels of total lipids when compared to the group only receiving formulated feed [146].…”

“…Te decomposed detritus and inorganic nutrients are consumed by cultured aquatic animals, which fnally build blocks for biomass. Tese natural biota (rich in proteins, lipids, amino acids, fatty acids, vitamins, trace elements, and bioactive compounds) improve the growth and nutritional values of numerous cultured aquatic animals (herbivorous/omnivorous species) [7,[12][13][14][15][16][17][18][19][20][21][22][23]. Tey can also replicate some of their efects with nonliving cells or components of the cell wall, particularly those involving the digestive and metabolic processes, intestinal balance, and immune system [20].…”