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This study aimed to estimate the efficacy of two pike-perch juvenile production technologies: exclusive Recirculating Aquaculture System (RAS) culture (the RAS group) and pond larviculture with a transfer to the RAS at the 42nd day post-hatch (DPH). Both direct weaning on dry feed (the Pond-D group) and 10-day gradual weaning using bloodworms (the Pond-B group) after transfer to the RAS were evaluated in pond-nursed fry. Their survival and morphometric indices were monitored after the RAS habituation period (first 10 days), after the 18-day post-habituation period and after an additional 30 days of on-grow. Our results indicate a negative allometric growth of the pond-nursed fish during the nursing period, which was slower (p < 0.0001) in comparison to the RAS-nursed fry (16.3 ± 0.4 vs. 17.8 ± 0.7%/day). After transfer, these fish grew faster than the RAS-nursed fry (7.7 ± 0.1, 4.9 ± 0.5 and 6.1 ± 0.6 during habituation, 8.5 ± 0.6, 9.3 ± 0.5 and 6.7 ± 0.1%/day during post-habituation period, in the Pond-B, Pond-D and RAS groups, respectively). However, four weeks afterwards, the RAS-nursed fry were again superior in terms of growth (4.0 ± 0.1, 3.6 ± 0.2 and 4.6 ± 0.2%/day, for the Pond-B, Pond-D and RAS groups, respectively), and this was accompanied by a significantly lower feed conversion ratio in this group. Although the survival of the RAS-nursed fry during the nursing period was lower in comparison to the pond-reared fry (11.3 vs. 67.3%), the RAS seems to provide a long-term growth advantage.

This research aimed to evaluate the reproductive potential of hatchery-reared (F1) pike-perch (Sander lucioperca) broodstock fed a commercial diet with low levels of long-chain polyunsaturated fatty acids (Lc-PUFA) and wild (F0) pike-perch broodstock fed forage fish. Reproductive parameters, including pseudogonadosomatic index (PGSI), egg size, latency time, hatching rate, embryo survival, and eggs’ fatty acid (FA) composition, as well as plasma sex hormone, glucose and immunoglobulin levels after hormone injection, were analyzed. The results showed low PGSI (10% in F1 vs. 14% in F0) and embryo survival (24% in F1 vs. 61% in F0) in F1 broodstock, but a satisfactory hatching rate (63% in F1 vs. 78% in F0) and larval size (4.6 mm in F1 vs. 4.7 mm in F0). A low arachidonic acid (ARA) percentage in F1 fish eggs (1.32%), along with increased immunoglobulin levels (17.31 g/L), suggests that immune system activation might have depleted the reserves of ARA in F1 fish, which is the key fatty acid for successful oocyte maturation. We assumed that the administration of more sustainable diets, based on terrestrial plant ingredients, is not inferior to higher-quality diets based on marine ingredients.

This study aimed to analyze an impact of Lactobacillus salivarius BGHO1 and Lactobacillus reuteri BGGO6-55 supplemented to Anemia franciscana cultivation medium on biochemical profile of hatched nauplii. Impacts of different BGHO1:BGGO6-55 ratios (75:25, 50:50 and 25:75) and their total concentrations (250 and 500 g/kg of Anemia cysts) at different timings of bacteria application (pre- and post-hatching) were examined. The effects were evaluated by quantification of naupliar peptide, soluble protein, phospho-, neutral and unsaturated lipid content. Uni and multifactorial analysis of variance (ANOVA) were used to estimate the effects of treatments relative to control and to model factor interactions, respectively Statistical analysis indicated that posthatching application of 75:25 strain ratio at high dose was associated with an increase of neutral lipid amount. Furthermore, factor interaction profiling identified positive correlation of lacto-bacilli concentration with the level of free amino acids/short peptides, phospho-, neutral and unsaturated lipids, but only at 50:50 strain ratio combination. Application of lower lactobacilli dose at 75:25 strain ratio caused an increase of soluble protein and phospholipid amount. Hypothetically, graded response of Artemia nauplii to lactobacilli supplementation was induced with different BGHO1 doses. It assumedly ranged from stress-response protein synthesis at lower doses to membrane permeability alterations and triglyceride-mediated defense mechanism activation at higher BGHO1 doses. In contrast to lactobacilli supplementation after Anemia hatching, pre-hatching application of lactobacilli was not associated with an increase of Anemia nutritive profile, though again there was a positive association of lactobacilli concentration with nutrient amount. This implicates interference of lactobacilli with the hatching process. Results presented here facilitate the design of future studies aiming to modify Artemia nutritive profil

The aim of this research was to improve nutritive value of fishmeal-based feed by lactobacilli in order to achieve satisfactory nutrient availability needed to support fish development. Feed was solid-state treated at a laboratory scale with the combination of Lactobacillus paracaseisubsp. paracasei BGHN14 and Lactobacillus rhamnosus BGT10 in different experimental settings, which included the variation of strain ratio, total lactobacilli concentration, percentage of moisture and duration of incubation. Short peptides, soluble proteins, phospho-, neutral and unsaturated lipids were quantified. Differences among treated and control feeds were evaluated by Student t-test, while Gaussian process regression (GPR) modeling was employed to simulate the incubation process and define the optimal treatment combination in the context of overall feed nutritional profile. Treatment duration was shown to be the critical determinant of final outcome, either as single factor or via interaction with strain ratio. Optimal nutrient balance was achieved with 12 h incubation period, 260% moisture, 75:25 and 50:50 BGHN14:BGT10 ratios and 200 mg of lactobacilli per g of dry feed. This study should serve as the basis for large-scale tests which would simulate on-farm production of both fishmeal-based and unconventional, lower cost aquafeed with added value.

The effects of different weaning strategies on survival, cannibalism and growth were investigated in pikeperch (Sander lucioperca) larvae. Two weaning strategies were tested with 15 days post hatch (DPH) larvae: Co-feeding and Supplementary feeding. Co-feeding was performed with Artemia nauplii and dry feed by the gradual reduction of nauplii either " 25% day(-1) or 14% day(-1), whereas supplementary feeding was performed with sudden weaning to exclusively dry feed while Artemia nauplii was the last meal of the day. Each strategy was tested in two time durations, for 4 and 7 days. Co-feeding weaning strategy seems to be more beneficial compare to supplementary feeding weaning strategy in response of lower mortality (%), higher growth and finally maximum total yield. Even though higher cannibalism was found in the larvae weaned for 7 days from 15-22 DPH but higher growth and survival in this group make this weaning strategy better than larvae weaned for 4 days from 15-19 DPH. Therefore, it is concluded that the co-feeding weaning strategy for 7 days from 15 to 22 DPH should be followed for successful larviculture of pikeperch.

Smuđ, Sander lucioperca, je vrsta koja ima dobru perspektivu u procesu diverzifikacije evropske kopnene akvakulture. Iako su različite tehnike njegovog razmnožavanja (prirodni mrest, veštačka i polu-veštačka propagacija) vrlo dobro opisane i dalje postoji širok prostor za razvoj i usavršavanje mnogih detalja. Do sada je objavljeno nekoliko publikacija o indukciji završnog sazrevanja gameta ove vrste korišćenjem različitih hormonalnih supbstanci (Ronyai., 2007; Kristan et al 2012, Zakes et al., 2012; Zarski et al., 2012). Najčešće upotrebljavani hormoni su ekstrakt šaranske hipofize - CPE, (Carp Pituitary Extract) i humani horioni gonadotropin (hCG, Human chorionic gonadotropin). Prirodni mrest, bilo u jezerima ili kavezima (Demska-Zakes and Zakes, 2002, Schlumberger i Proteau, 1996; Ruuhijarvi and Hyvarinen, 1996, Steffens et al., 1996), izgleda najjednostavniji, ali u isto vreme, manje pouzdan metod, kako je uspeh mresta visoko zavisan ne samo od stadijuma zrelosti matica, već i od nekontrolisanih spoljašnjih ekoloških faktora (npr. temperatura i kvalitet vode). Nasuprot tome, veštačka, ili poluveštačka propagacija bi mogli biti u prednosti za mnogo pouzdaniju i sinhronizovaniju produkciju larvi. Ove tehnike mogu biti izvedene bilo mrestom u tanku ili ručnim istiskanjem (Kucharczyk et al., 2007). U slučaju reprodukcije u veštačkom okruženju , vreme latencije (LT -, izračunat kao interval od prve hormonalne injekcije do ovulacije) je vrlo nesinhronizovano u većini studija. Zarski et al. (2011) su razvili novu klasifikaciju preovulatornih stadijuma sazrevanja ovocita za smuđa sa svrhom bolje sinhronizacije ovulacije. Iako postoji poboljšanje sinhronizacije, period od prve do poslednje ovulacije varira 10-25 časova. Nepredvidljivo vreme ovulacije uzrok je ozbiljnom problemu pri ručnom istiskanju ikre kod smuđa, što ponekad dovodi do spontane ovulacije i gubitka ikre u tanku (Zarski et al., 2011). U ovoj studiji korišćena je kombinovana metoda prezentovana od strane Ró

Akvakultura je sektor proizvodnje hrane u svetu sa najbržim rastom. Međutim, uzgoj vodenih životinja je i dalje na daleko nižem stepenu razvoja u odnosu na uzgoj kopnenih životinja. S druge strane, iako je globalni trend proizvodnje u konstantnom rastu, evropska slatkovodna akvakultura beleži stagnaciju u poslednje dve decenije. Radi unapređenja proizvodnje slatkovodnih organizama na starom kontinentu, predožena su dva pravca: pratiti način razvoja gajenja kopnenih životinja i usredsrediti se na mali broj vrsta; ili pratititi princip diverzifikacije, pre svega gajenjem novih vrsta. Kao jedan od glavnih kandidata za diverzifikaciju opisan je smuđ. Gajenje smuđa u intenzivnom sistemu vezano je za recirkulacioni akvakulturni sistem (RAS), koji omogućava visoku kontrolu parametara proizvodnje. Osnovni uslov gajenja nove vrste u RAS-u je upravljanje njenim životnim ciklusom. Stoga, prvi zadatak pri uzgoju smuđa u RAS-u jeste definisanje tehnoloških parametara za stabilnu proizvodnju mlađi pogodne za intenzivan uzgoj. U tom smislu, početne studije su fokusirane na veštački mrest, uzgoj larvi i mlađi. Većina prethodno objavljenih studija o veštačkom mrestu smuđa koristile su divlje matice kao osnovni materijal. Međutim, korišćenje divljih matica ostavlja životni ciklus otvoren. Nadalje, za potrebe uzgoja u intenzivnom sistemu, osnovni preduslov jeste da mlađ konzumira industrijsku koncentrovanu hranu. U slučaju smuđa, opisane su dve tehnologije proizvodnje mlađi naviknute na suvu hranu - proizvodnja mlađi isključivo u RAS-u; i proizvodnja mlađi kombinacijom ekstenzivnog jezerskog sistema i RAS-a. Prethodno objavljene studije o intenzivnom uzgoju larvi smuđa bavile su se optimalnim danom početka tranzicije ishrane larvi sa žive na suvu hranu. Međutim, strategija ishrane, odnosno način prelaska sa žive na suvu hranu nisu bile predmet njihovog istraživanja. Takođe, nekoliko objavljenih studija opisalo je navikavanje jezerski uzgojene mesečne mlađi smuđa na koncentrovanu hranu, Aquaculture is the fastest growing food production sector in the world, however, rearing of aquatic animals is still on the far lower developmental stage compared to breeding of terrestrial animals. On the other hand, although on the global level aquaculture production is constantly growing, European freshwater aquaculture is rather stagnant in the last two decades. In order to improve production of freshwater species on the old continent, two directions have been suggested – either to follow developmental pattern of terrestrial animals and focus on the small number of species; or to follow the diversification principle, mainly through breeding of new species. Pikeperch was described as one of the most promising candidates for the task of diversification. Pikeperch intensive rearing is connected to the recirculation aquaculture system (RAS), which allows high control of production parameters. In order to breed the new specie in RAS, management of its life cycle is prime requirement. Therefore, definition of technological parameters for stable production of fingerlings suitable for intensive on-grow is the first task for pikeperch RAS rearing. In that sense, initial studies are focused on artificial reproduction, larvicutlure and juvenile rearing. Most of the previously published studies on the pikeperch artificial reproduction used wild fish as the main material. However, usage of wild broodstock leaves the life cycle opened. Further, fingerling material for intensive rearing must be adapted on the commercial diets. In case of pikeperch, two technologies have been described for production of juveniles habituated to dry feed – juvenile production in RAS exclusively; and juvenile production in combined pond-RAS system. Previously published studies on pikeperch larviculture were dealing with optimal age for weaning. Nevertheless, weaning strategies, i.e. mode of transition from live to inert diets was not the subject of their research. Likewise, several studies describ