Antifungal treatments in artificial incubation of crayfish eggs (Pacifastacus leniusculus, Astacidae): Searching for alternatives to formaldehyde

Abstract

Key-words:antifungal treatment, artificial incubation, astacid crayfishConsidering the concerns about the safety of the use of formaldehyde as antifungal agent, the effects of three alternative chemicals (potassium sorbate, copper hydroxide and magnesium chloride) were tested in the artificial incubation of signal crayfish (Pacifastacus leniusculus) eggs. Eight treatments were performed during 15 min every other day: formaldehyde at 3000 ppm (control), potassium sorbate at 5000 and 10 000 ppm, copper hydroxide at 40, 60, 80 and 200 ppm, and magnesium chloride at 10 000 ppm. Eggs were incubated in a flow through system at a density of 20 eggs·cm −2 . After 61 days of incubation, the highest efficiencies were obtained with 200 ppm of copper hydroxide (77.6% of survivors to stage 2) with no significant differences from the control (74.3%). Lower concentrations of copper hydroxide resulted in high egg mortality whereas potassium sorbate and magnesium chloride were ineffective to avoid fungal growth and total egg mortality took place. From the obtained results, copper hydroxide baths at 200 ppm could be considered as a good alternative to formaldehyde. fongique et une mortalité totale des oeufs intervenait. À partir des résultats obtenus, des bains d'hydroxyde de cuivre à 200 ppm peuvent être considérés comme une bonne alternative au formaldéhyde.

Sodium chloride as effective antifungal treatment for artificial egg incubation inAustropotamobius pallipes

“…Malachite green was used as the most effective fungicide for many years in aquaculture. However, the use of this chemical agent on food fishes and their eggs was prohibited for aquaculture in USA and EU since 1991 and 1997, respectively, because of its teratogenic and carcinogenic effects (Carral et al, 2009). Formaldehyde is currently the most effective antifungal agent approved for using in aquaculture in USA and EU ; however, its applying in aquaculture presents potential hazard for aquatic environment as well as farm staff (Arndt et al, 2001).…”

“…Jodisol preparation with povidonum iodinatum as active substance in a static bath and its combination with the removal of dead eggs (Policar et al, 2006) might be one possibility. Carral et al (2009) tested three chemicals with copper hydroxide being the most effective one.…”

A model of co-occurrence: segregation and aggregation patterns in the mycoflora of the crayfish Procambarus clarkii in Lake Trasimeno (central Italy)

“…Although the importance on crayfish diseases has recently proliferated (Hirsch et al 2008;Diéguez-Uribeondo 2009), it seems more important focusing studies on a single host-parasite relationship rather than analyzing the entire mycoflora living on the exoskeleton. The absence of detailed studies on the entire ecto-symbiontic mycoflora is probably due to the fact that (1) some diseases are occasional (pathogens of which are of difficult collection), and (2) economic impact is more relevant in cray-fish farming (see Carral et al 2009) where less parasites occur than in natural populations (Diéguez-Uribeondo 2009).…”

Antifungal effect ofOriganum onitesessential oil as an alternative to formalin in the artificial incubation of narrow-clawed crayfish (Astacus leptodactylusEschscholtz, 1823)

“…In addition, malachite green was prohibited to use for aquaculture because of its teratogenic and carcinogenic effects (Carral et al . ). Therefore, alternative eco friendly antifungals are required such as medicinal plants.…”

“…; Melendre et al . ; Carral, González, Celada, Sáez‐Royuela, Melendre, González & García ; Sáez‐Royuela, Melendre, Celada, Carral, González, González & García ; Kouba, Carral, Buric, Mraz, Policar & Kozak ; González, Celada, Melendre, Carral, Sáez‐Royuela, Gonález & García ; Policar, Smyth, Flanigan, Kouba & Kozak ). Celada et al .…”