The use of formaldehyde for the disinfection of maternally incubated eggs of noble crayfish (Astacus astacus)

Abstract The high mortality of maternally incubated eggs represents a serious problem that prevents the development of noble crayfish (Astacus astacus) farming in Italy. In this experiment, formaldehyde bath technique has been tested with maternally incubating females. The survival rate of maternally incubated eggs, exposed to progressively reduced concentrations of formaldehyde (4000, 3000, 2000, 1000, 1500 and 500 mg l−1), has been compared with that of untreated controls for two consecutive years (2010 and 2011). The formaldehyde treatments were administered as disinfection baths, for a period of 15 min, twice a week. A concentration of formaldehyde of 500 mg 1−1, or greater, was found to be effective in controlling egg mortality, without apparent harming the female broods

Freshwater bivalves rearing: a brief overview

Freshwater bivalves farming is principally focused on freshwater pearl production in Asia and conservation aquaculture in USA while in Europe is almost completely unknown. High larval mortality is considered the bottleneck in freshwater bivalve larval rearing and methods currently used in marine bivalve larval rearing can be transferred in freshwater mussels. It is likely that probiotics and aquatic microbiology will play a key role also in freshwater bivalves larval rearing. Alternative applications of freshwater mussel rearing should be studied in deep in the future as integrated productions, bioindication projects and utilization of freshwater mussel meal as potential source for fish feeds. The aim of this review is to give a description of potential applications for freshwater bivalve rearing and possible future perspectives

Animal welfare in brown trout farming: hematological results

The effect of stress resulting from fish farming has received considerable attention in this last period and fish welfare in aquaculture is a relevant topic, very important for the future of aquaculture (Watson et al., 2004; Klinger et al., 1996; Peres et al., 2004; Ron et al., 1995;Wagner et al., 1995;Watson et al., 1998). Brown trout farming is less developed then rainbow trout farming, but this kind of fish farming is increasing, mainly for fish conservation and restocking aquaculture

Hybrid sturgeon 'AL' diets

In this experimentation, corn gluten (CG) and pea meal (PM) were tested as potential protein sources in hybrid sturgeon âALâ. One hundred and twentyâeight hybrid sturgeons âALâ (Acipenser naccarii A Acipenser baeri) (initial body weight 364.8 ± 4.5âg) were utilized with four experimental diets and four replicates each; the experimental design was 4 A 4. Four isonitrogenous [crude protein=40% dry matter (DM)] and isoenergetic (gross energy=20âMJâkgâ1 DM) diets were formulated containing different levels of CG with or without PM and tested against a control diet that was fish meal (FM) based. Diets were as follows: CG55 contained 55% of corn gluten; diet CG55PM25 contained 55% CG and 25% PM; diet CG45PM25 contained 45% of corn meal and 25% of PM; and diet FM was control, based on FM. Fish fed with the PM diet showed lower values of feed conversion ratio (FCR) and specific growth rate (SGR) (FCR=4.53 ± 2.51 in the CG55PM25 diet; FCR=4.09 ± 1.45 in the CG45PM25 diet; SGR=0.20 ± 0.07 in the CG55PM25 diet; SGR=0.19 ± 0.11 in the CG55PM25 diet). The results of tissue proximate composition confirmed the results obtained from productive traits. This study indicates that CG meal but not PM could be utilized as a substitute of FM in hybrid sturgeon âALâ nutrition

Utilization of Rice Protein Concentrate in Siberian Sturgeon (Acipenser baerii Brandt) Nutrition

The aim of this research is the substitution of fish meal with rice protein concentrate (RPC) in the nutrition of Siberian sturgeon (Acipenser baerii) diet. 240 sturgeons of initial mean body weight of 19.1±6.7 g were used. 3 isonitrogeonous (CP 42.4%) and isoenergetic (19.9 KJg-1 DM) diets were formulated with 20% of RPC inclusion (R20), 35% inclusion (R35), 53% inclusion (R53) against a control diet, fish meal based (FM); feeding ratio was 1.5% of BW. All the diets and fish fillets were analyzed to determine the proximate composition. The diet amino acid composition was measured and fillet colour was detected at the end of experimentation. Fish growth showed very good performances of sturgeon fed with high RPC inclusion, but these data were not considered conclusive because of technical problems during the experimentation. However, considering that the highest level of RPC in the sturgeon diets corresponded to an almost complete substitution of fish meal in the fish diet, the result obtained from fish quality analysis showed no adverse effect of experimental diets, with the only limitation of high muscle lipid storage, in fish fed with highest level of RPC inclusion.10.4194/1303-2712-v15_2_1310.4194/1303-2712-v15_2_1

Random Assignment Problems on 2d Manifolds

We consider the assignment problem between two sets of N random points on a smooth, two-dimensional manifold Ω of unit area. It is known that the average cost scales as EΩ(N) ∼ 1 / 2 πln N with a correction that is at most of order lnNlnlnN. In this paper, we show that, within the linearization approximation of the field-theoretical formulation of the problem, the first Ω -dependent correction is on the constant term, and can be exactly computed from the spectrum of the Laplace–Beltrami operator on Ω. We perform the explicit calculation of this constant for various families of surfaces, and compare our predictions with extensive numerics