The effect of broodstock origin, stocking density and weaning strategies on the success of artificial reproduction, larviculture and juvenile on-grow of pikeperch (Sander lucioperca L., 1758)

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, međutim, mnoga pitanja sa aspekta tehnologije, ishrane i porekla mlađi neophodna za stabilizaciju ovog proizvodnog procesa ostala su nerešena. U saglasnosti sa opisanim problemima, osnovni cilj istraživanja u okviru ove disertacije je da kroz četiri studije unapredi tehnologiju prozivodnje mlađi smuđa pogodne za intenzivni uzgoj u RAS-u. U prvoj studiji poređen je uspeh veštačkog mresta matica gajenih u RAS-u i divljih matica. Obe grupe prethodno su zimovale u spoljašnjim jezerskim objektima...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 described the habituation to dry diets in pond-reared month-old juveniles. However, many issues from aspects of technology, nutrition and juvenile origin remained opened. With regard to described bottlenecks, the main research outcome of this thesis is to improve the production technology of pikeperch juveniles suitable for RAS rearing. Research has been conducted in four studies..

Effect of thermal management on vitellogenesis and maturation in indoor-reared pikeperch (Sander lucioperca)

The present study aimed to assess the effects of thermal manipulation on the vitellogenesis and final oocyte maturation (FOM) in pikeperch. Two groups of fish were stocked in two separate tanks of the climate chamber. One group was stocked at 10-month age (THERMAL), while the other was continually kept under stable photothermal conditions until 19-month-age (CONTROL) and then transferred to a climate chamber. The progress of vitellogenesis was assessed via evaluation of the oocyte diameter at the mid- and late-autumn phases, and the gonadosomatic index (GSI) at the late-autumn phase. Finally, females from the CONTROL group were hormonally stimulated before (WARMING) and after (STABLE) increase of the temperature from wintering to spawning, and the FOM progress, ovulation and plasma levels of 17 α, 20β dihydroxy progesterone (DHP) were assessed. Significantly larger oocytes at the mid-autumn phase (878.8 ± 40.1 μm vs 836.5 ± 46.5 μm) as well as the GSI at the end of the autumn phase (10.5 ± 1.7% vs 7.6 ± 1.1%) were noticed in THERMAL fish. Significantly faster FOM was seen in fish under the WARMING post-stimulation regime, and these fish had higher DHP levels at the moment of hormonal stimulation (5.4 ± 1.4 ng/ml vs 3.8 ± 1.2 ng/ml). According to the obtained results, it appears that photothermal induction of fish at a younger stage might have a positive impact on the first spawning, while the WARMING thermal regime seems to be more efficient in stimulating the FOM in fish upon first wintering

Dinamika zajednica ukupnih koliformnih i fekalnih koliformnih bakterija u novoizgrađenim lagunama za prečišćavanje vode

Konstruisani vetlandi se koriste za prečišćavanje otpadnih voda zbog svoje efikasnosti, isplativosti izrade sistema i pozitivnog uticaja na životnu sredinu. Fekalne koliformne bakterije predstavljaju indikatore zagađenja voda jer ukazuju na potencijalno prisustvo patogenih mikrooganizama kao i drugih zagađujućih materija, a dospevaju u vodene ekosisteme direktno iz kanalizacionih sistema, ali i difuznih humanih i životinjskih otpadnih materija. Zbog toga je ovo istraživanje usmereno na praćenje dinamike preživljavanja ukupnih koliformnih i fekalnih bakterija u otvorenom površinskom konstruisanom vetlandu sa emerznom vegetacijom. Preživljavanje mikroorganizama, kao i njihova distribucija u vetlandima, zavisi od tipa vetlanda, ali i drugih ekoloških pojava koje utiču na njihov razvoj, gubitke i uništenje. U pogledu prečišćavanja otpadnih voda, vetlandi imaju učinak kao biofilteri, jer se u njima kombinovanjem fizičkih, hemijskih i bioloških procesa vrši uklanjanje kontaminanata. Fekalne koliformne bakterije se vezuju za suspendovane čestice, koje se zadržavaju na biljkama iz vetlanda i po njihovoj žetvi se zajedno sa biljkama uklanjaju iz sistema. U ovoj studiji je ispitivana efikasnost novoizgrađenog vetlanda, koji se nalazi na istraživačkom poligonu “Mali Dunav” u Centru za ribarstvo i primenjenu hidrobiologiju (CEFAH) Poljoprivrednog fakulteta, Univerziteta u Beogradu, fakultetskog dobra “Radmilovac”. U tu svrhu je konstruisan vetland koji se sastoji iz jedne ulazne lagune, namenjene za predtretman vode i još dva bazena, u kojima se prirodno tretira površinska otpadna voda i otpadna voda iz domaćinstava. U ovom radu ispitivane su vrednosti ukupnih i fekalnih koliformnih bakterija, petodnevna biohemijska potrošnja kiseonika (BPK5), i ukupne suspendovane materije. Istraživanje je započeto u martu 2012.godine i završilo se u februaru 2013.godine. Za praćenje indikatorskih organizama, kao što su ukupne i fekalne koliformne bakterije korišćene su standardne mikrobiološke metode uzorkovanja i tretiranja uzoraka u laboratoriji. Tokom jednogodišnjeg perioda praćenja parametara na mesečnoj bazi, vrednosti BPK5 su varirale od 15 mg/L do 52 mg/l, a vrednosti TSS od 2.0 mg/L do 89.6 mg/L. Na godišnjem nivou prosečne vrednosti ovih parametara nisu prelazile propisani limit. Mesečno opterećenje sistema sa ukupnim koliformnim bakterijama se kretalo od 5.0×102 CFU/ml do 5.19×105 CFU/ml, a opterećenje fekalnim koliformnim bakterijama je variralo od 5.0×101 CFU/ml do 1.4×103 CFU/ml. Prosečna godišnja vrednost opterećenja sistema ukupnim koliformnim bakterijama je iznosila 9.93×103 CFU/ml, a fekalnim koliformnim 4.05×103 CFU/ml. Na kraju perioda ispitivanja prosečna vrednost ukupnih koliformnih bakterija u efluentu je umanjena za 50%, a prosečna vrednost fekalnih koliformnih bakterija za isti period je redukovana za 97%. Smanjenje brojnosti fekalnih koliformnih bakterija ukazuje da je primena konstruisanih vetlanda opravdana za korišćenje u svrhe obuhvaćene ovim istraživanjem. Radi dodatnog poboljšanja efikasnosti rada vetlanda potrebno je primeniti neke od sledećih mera: povećati raznovrsnost emerzne vegetacije, formirati dodatne ćelije kojima će se poboljšati hidraulički proticaj u vetlandu, da bi se dostigle još niže vrednosti fekalnih koliformnih bakterija u efluentu

Nursing of Pike-Perch (Sander lucioperca) in Recirculating Aquaculture System (RAS) Provides Growth Advantage in Juvenile Growth Phase

publishedVersio

Effect of Weaning Strategies on Growth and Survival of Pikeperch, Sander lucioperca, Larvae

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

Solid state treatment with Lactobacillus paracasei subsp. paracasei BGHN14 and Lactobacillus rhamnosus BGT10 improves nutrient bioavailability in granular fish feed

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

Reproduction of Hatchery-Reared Pike-Perch (Sander lucioperca) Fed Diet with Low-Marine-Ingredients: Role of Dietary Fatty Acids

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

Evaluation of Post-Larval Diets for Indoor Weaned Largemouth Bass (Micropterus salmoides)

This study aimed to evaluate different commercial diets (Otohime C1, Aller Futura (AF), Biomar Inicio Plus (BIP)) and one experimental feed (EF) in terms of their effectiveness as post-larval diets for indoor weaned largemouth bass, LMB (Micropterus salmoides). Key variations in the content of nutritive values were monounsaturated fatty acid (MUFA) and highly unsaturated FA (HUFA) ω3. Fish were fed with one of four tested diets from the 33rd to the 40th day post-hatch (DPH). Biometric indices, digestive enzyme-specific activities, thyroid hormone status, and mRNA expression of genes coding for skeleton, neuron, and muscle growth were analyzed. The lowest skeletal deformity rate and highest survival among the treatments were seen in BIP-fed fish. Dietary lipids, with an appropriate balance between MUFA and polyunsaturated FA (PUFA), alongside amino acid balance, were shown to be the main contributors to the growth of the skeleton and/or fish survival. On the other hand, fish growth is correlated with fish digestive capacity and feed moisture percent rather than feed quality. Unexpectedly, BIP-fed fish were attributed with the lowest expression of skeleton differentiation markers, which may reflect the sacrifice of scale and/or cranium growth at the expense of somatic growth. This study highlights the role of non-marine ingredients in the nutrition of post-larval LMB

The effect of broodstock origin, stocking density and weaning strategies on the success of artificial reproduction, larviculture and juvenile on-grow of pikeperch (Sander lucioperca L., 1758)

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, međutim, mnoga pitanja sa aspekta tehnologije, ishrane i porekla mlađi neophodna za stabilizaciju ovog proizvodnog procesa ostala su nerešena. U saglasnosti sa opisanim problemima, osnovni cilj istraživanja u okviru ove disertacije je da kroz četiri studije unapredi tehnologiju prozivodnje mlađi smuđa pogodne za intenzivni uzgoj u RAS-u. U prvoj studiji poređen je uspeh veštačkog mresta matica gajenih u RAS-u i divljih matica. Obe grupe prethodno su zimovale u spoljašnjim jezerskim objektima...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 described the habituation to dry diets in pond-reared month-old juveniles. However, many issues from aspects of technology, nutrition and juvenile origin remained opened. With regard to described bottlenecks, the main research outcome of this thesis is to improve the production technology of pikeperch juveniles suitable for RAS rearing. Research has been conducted in four studies..