Agata Kowalska

Impact of intraperitoneal and intramuscular PIT tags on survival, growth, and tag retention in juvenile pikeperch, Sander lucioperca (L.)

Impact of intraperitoneal and intramuscular PIT tags on survival, growth, and tag retention in juvenile pikeperch, Sander lucioperca (L.) The aim of the study was to compare the effects of intraperitoneal (group P) and intramuscular (group M) methods of implanting PIT tags on the growth, condition, and survival of juvenile pikeperch, Sander lucioperca (L.) (body weight about 82 g) and tag retention. After tagging, the fish were held in recirculating aquaculture systems (RAS) and reared on commercial feed for 56 days. No significant differences were noted in fish growth rate or condition between the experimental groups (groups P and M) and the control group that was not tagged (group C; P > 0.05). The feed conversion ratios were also of similar values (FCR - 1.2-1.3; P > 0.05). Tagging did not impact fish survival, which was 98.9% in group P and 100% in groups M and C on the final day of the experiment (P > 0.05). Tag retention in both groups was also 100%. The results of this study confirm that both tagging methods are suitable for juvenile pikeperch. The PIT tags were noted to migrate in the body cavity in group P (47.2% of tagged fish). Accordingly, the intramuscular method for implanting PIT tags is recommended for juvenile pikeperch (body weight > 60 g). Wpływ dootrzewnowej i domięoeniowej implantacji znaczków PIT na przeżywalność, wzrost i trwałość oznakowania młodocianego sandacza, Sander lucioperca (L.) W ostatnich latach coraz większą popularność zdobywa metoda indywidualnego znakowania ryb pasywnymi transponderami, tzw. znaczkami PIT (Passive Integrated Transponder). Dobór właściwego systemu znakowania ryb jest zależny od gatunku, stadium rozwoju osobniczego, sposobu i miejsca implantacji w ciele oraz specyficznych celów danego programu badawczego. Celem prezentowanych badań było porównanie efektów stosowania dootrzewnowej (grupa P) i domięoeniowej (grupa M) metody implantacji znaczków PIT (rys. 1) na tempo wzrostu, kondycję, przeżywalność młodocianego sandacza, Sander lucioperca (L.) (masa ciała ok. 82 g) i retencję znaczków. Po poznakowaniu ryby przetrzymywano w obiegach recyrkulacyjnych i podchowywano na paszy sztucznej przez 56 dni. Nie odnotowano istotnych różnic w tempie wzrostu i kondycji ryb z grup doświadczalnych (grupy P i M) względem, niepoznakowanej grupy kontrolnej (grupa C; P > 0,05; tab.1). Współczynniki pokarmowe pasz przyjęły również zbliżone wartości (FCR - 1,2-1,3; P > 0,05). Znakowanie nie wpłynęło na przeżywalność ryb, która w dniu zakończenia podchowu wynosiła 98,9% (grupa P) i 100% (grupa M i C) (P > 0,05; tab. 1). Retencja znaczków w obydwu grupach była równa 100%. Uzyskane wyniki potwierdziły, iż w przypadku młodocianego sandacza dobrze sprawdzają się obie analizowane metody znakowania. W grupie P zaobserwowano zjawisko przemieszczenia się PIT w jamie ciała (47,2% znakowanych ryb). Potencjalnie może to utrudniać identyfikację/odczyt znaczków. W związku z tym wydaje się, że w przypadku juwenalnego sandacza (masa ciała > 60 g) należy raczej rekomendować metodę domięśniowej implantacji znaczków PIT.

Cryopreservation of Acropora digitifera sperm with use of sucrose and methanol based solution

Coral biodiversity has recently been considered an important topic in environmental studies. Biodiversity could be preserved with successful cryopreservation of endangered species gametes or embryos. Herein, we developed cryopreservation protocols for Acropora digitifera sperm with use of sucrose and methanol based extender. We studied cryopreservation of A. digitifera sperm with floating frames, allowing the placement of 250 μl French straws 4 cm above the liquid nitrogen surface, resulting in a 40 °C/min freezing rate. This method enabled the successful cryopreservation of sperm in 0.9 M sucrose supplemented with 20% methanol. In this protocol, we used a 1:3 (sperm:extender) dilution ratio. The fertilization ratios of freezing:thawed sperm were similar to the control and reached 63%. This method might be a valuable option in the formation of A. digitifera gene banking. Further studies are needed to explore possibilities of using this method in cryopreservation of other corals sperm.

Slaughter yield and growth performance indexes of pikeperch (Sander lucioperca (L.)) selects reared in recirculating aquaculture systems at suboptimal temperatures

Abstract The aim of the study was to determine the impact diet has on the basic growth performance indexes and slaughter yield of pikeperch selects (body weight > 1.35 kg). Tagging the individual fish with PIT tags also permitted determining the impact of sex on the studied growth performance indexes. The fish were fed two diets with protein/fat/carbohydrate ratios of 50.5/11.8/29.4 in group I and 47.1/14.1/29.0 in group II. Neither the diets nor the sex of the fish has a significant impact on the final body weight or condition of the pikeperch (P > 0.05). Significant differences were noted between the relative indicators of pikeperch growth performance (SGR and DGR) (impact of diet and sex; P < 0.05). Among the growth performance indexes analyzed, e.g., viscerosomatic (VSI), hepatosomatic (HSI), and gonadosomatic (GSI), statistically significant differences were noted with regard to HSI (impact of diet and sex) and GSI (impact of sex) (P < 0.05). The analysis of the relative values of the pikeperch body parts studied (expressed in % body weight) indicated that the studied parameters had significant impacts on the slaughter yield of the viscera (impact of sex) and skin (impact of diet), as well as on gutted whole fish, gutted and headed whole fish, fillets with skin, and skinned fillets (impact of sex) (P < 0.05). The slaughter yields of the skinned fillets of males from both dietary treatments were approximately 5% higher than those of the females.

Impact of diets supplemented with rapeseed, soy, and sunflower oils on growth rates and the histological picture of the livers of juvenile pikeperch, Sander lucioperca (L.)

Impact of diets supplemented with rapeseed, soy, and sunflower oils on growth rates and the histological picture of the livers of juvenile pikeperch, Sander lucioperca (L.) Juvenile pikeperch (120 g initial body weight) were fed a commercial diet (group CD) or experimental diets supplemented with rapeseed (group RO), soy (group SO), or sunflower (group SFO) oils for 55 days. The experimental diets were made by adding the given vegetable oil (VO) in quantities of 160 g kg-1 feed (84% of the total raw lipid in the diet) to a base of an extruded, commercial diet (containing 30 g kg-1 raw lipid). The dietary treatments had no significant influence on fish growth rates, apparent net protein retention (ANPR), or apparent net energy retention (ANER) (P > 0.05). The apparent lipid retention (ALR) in group SO was significantly higher than in the other groups (P < 0.05). The dietary treatments tested had a significant impact on the size of the hepatocytes and their nuclei, as well as on the nucleocytoplasmic index values (P < 0.05). No significant differences were noted in the overall image of the hepatocytes (degree of vacuolization or hepatocyte degeneration (P > 0.05)). Wpływ żywienia paszami suplementowanymi olejem rzepakowym, sojowym i słonecznikowym na tempo wzrostu i obraz histologiczny wątroby juwenalnego sandacza Sander lucioperca (L.) Juwenalnego sandacza o początkowej masie ciała 102 g podchowywano w obiegu recyrkulacyjnym i żywiono przez 55 dni paszą komercyjną (grupa CD) lub paszami eksperymentalnymi suplementowanymi olejem rzepakowym (grupa RO), sojowym (grupa SO) lub słonecznikowym (grupa SFO). Pasze doświadczalne uzyskiwano dodając do ekstrudowanej, komercyjnej paszy bazowej (zawierającej 30 g kg-1 tłuszczu surowego) dany olej roślinny (VO) w ilości 160 g kg-1 paszy (84% całkowitego tłuszczu surowego w paszach). W efekcie otrzymano pasze o porównywalnym składzie chemicznym: białko surowe 449,0-452,1 g kg-1 paszy (sucha masa (d.m.)), tłuszcz surowy 189,1-191,1 g kg-1 paszy (d.m.), popiół surowy 73,9-74,5 g kg-1 paszy (d.m.). Kontrolną grupę ryb żywiono komercyjną paszą pstrągową o składzie chemicznym zbliżonym do pasz eksperymentalnych (pasza CD; tabela 1). Analizowano wpływ stosowania ww. pasz na wskaźniki wzrostu ryb, retencji nutrientów i energii oraz budowę histologiczną wątroby (tabela 2). Nie stwierdzono istotnego wpływu żywienia na tempo wzrostu ryb, w tym również na współczynniki retencji białka (ANPR) i energii (ANER) (P > 0,05; tabela 3). Współczynnik retencji tłuszczu (ALR) w grupie SO przyjął istotnie wyższą wartość niż w pozostałych grupach (P < 0,05). Wartość indeksu hepatosomatycznego (HSI) była zbliżona. Stwierdzono natomiast istotny wpływ testowanych pasz na wielkość hepatocytów i ich jąder, a także wartość indeksu nukleocytoplazmatycznego (P < 0,05). Nie odnotowano natomiast istotnych różnic w ogólnym obrazie hepatocytów (stopniu wakuolizacji i degeneracji komórek wątrobowych) (P > 0,05; tabela 4).

Propiscin — A safe anaesthetic for pikeperch (Sander Lucioperca L.)

The aim of this work was to determine the impact of etomidate (Propiscin) dose (1 and 2 ml l-1) and exposure time (2 and 10 min) on the biochemical and haematological parameters of juvenile pikeperch (Sander lucioperca) [mean body length (Lc) 25.9 cm; body weight (W) 189.9 g] that were reared in a recirculating aquaculture system (RAS). Significant changes in the mean values of total protein, globulin, calcium, magnesium, and ammonia were noted in all groups immediately following exposure. The greatest changes in the haematological indicators were observed in groups subjected to 10-min exposure at both doses of the anaesthetic. The specimens from these groups had higher values for white blood cells (WBC), red blood cells (RBC), haemoglobin (HGB), haematocrit (HCT), and mean corpuscular volume (MCV). Statistically significant differences in these same parameters were also noted in the groups of fish exposed to the anaesthetic for 2 min at a dose of 2 ml l-1, but they were not as pronounced. Twenty-four h following exposure to etomidate, all blood parameters in the experimental groups were comparable to those of the control group. Etomidate can be recommended as a safe, effective anaesthetic for pikeperch.

Impact of diet and culture conditions on the body shape of crucian carp (Carassius carassius L.)

The ecological consequences of hatchery rearing have been widely studied, whereas there are relatively few investigations of the impact diets and culture conditions have on morphological variation, especially in rare or endangered species. The aim of the current study was to determine the impact of diet and culture conditions on the morphometric features of crucian carp (Carassius carassius), which is a species characterised by a highly variable body shape. In the first experiment, the impact of feed type on crucian carps body shape was tested, while in the second, the impact of culture conditions on the body shape was determined. Feed type and culture conditions significantly impacted the shape and the morphology of crucian carp. Fish-fed larval chironomids exhibited the least variation in biometric characters, while those fed high-energy-formulated feed exhibited the greatest variation. In turn, individuals cultured in ponds exhibited greater variability in measurable characters than did fish cultured in recirculating systems. The body depth index of fish fed different feeds or cultured under controlled conditions did not differ significantly in comparison to wild crucian carp. The phenotypes of the cultured fish from the two experiments were similar to those of individuals inhabiting the natural environment.

Growth and survival in earthen ponds of different sizes of juvenile pike reared in recirculating aquaculture systems

Abstract The aim of the study was to determine the growth and survival of juvenile pike, Esox lucius L., reared in recirculating aquaculture systems (RAS) and then released into earthen ponds. Three different sizes of fish were used in the experimental releases of stocking material with mean body weights of 1.5 g (group S), 7.0 g (group M), and 18.5 g (group L) which were reared in a recirculating aquaculture system and fed formulated feed exclusively. Before the fish were released, they were tagged with visible implant elastomer (VIE) tags. The highest final body weight was attained by the fish in group S, the mean body weight of which was 85.5 g, which was significantly statistically higher than in the other groups (P < 0.001). No differences in survival were noted among the groups. Positive biomass increases were only exhibited in group S (37 kg ha-1), and it was highly statistically significantly greater than it was in the other groups (P < 0.001). The results of the experiment could indicate that the suitability of juvenile pike for stocking depends on its size at release. Extending the rearing period in RAS resulted in poorer stocking results in the ponds.

Impact of feeding pikeperch Sander lucioperca (L.) feeds of different particle size on the results of the initial on-growing phase in recirculation systems

Abstract Two experiments were performed to analyze the impact of applying two formulated feeds of different particle sizes (feed 1 - particle length - 2.8 mm; feed 2 - 4.5 mm) on the results of on-growing pikeperch in recirculating aquaculture systems (RAS). Two pikeperch size classes were used: in experiment I the mean body weights (BW) were 74 and 102 g, and in experiment II the BW were 125 and 170 g. The fish in both size groups in experiment I that were fed feed 1 achieved significantly quicker growth and better values of the feed conversion ratio (FCR) values (P < 0.05). Larger intragroup differences in final BW and condition coefficients were noted in the fish groups receiving feed 2. No significant differences in growth, condition, or FCR values were noted in either of the two pikeperch size groups fed experimental feed in experiment II. Pikeperch prefers feed of smaller particle size. In the initial on-growing phase, and particularly for fish of BW 70-125 g, it is recommended to use feed with the smallest particle size.

Impact of feeding juvenile pikeperch (Sander lucioperca (L.)) diets supplemented with vegetable oils on proximate body composition and fatty acid profile

Impact of feeding juvenile pikeperch (Sander lucioperca (L.)) diets supplemented with vegetable oils on proximate body composition and fatty acid profile Juvenile pikeperch, Sander lucioperca (L.) were reared in recirculating aquaculture systems for 55 days and fed a commercial trout diet (group CD) or diets supplemented with the following vegetable oils (VO): rapeseed (group RO), soy (group SO), sunflower (group SFO). The level of feed supplementation with VO was 84% of the total crude fat (CF), which was achieved by adding 160 g VO kg-1 feed to the commercial feed base that contained 30 g CF kg-1 feed. The diets tested did not have a significant impact on the proximate composition of the whole fish, fillets, or viscera (P > 0.05). Significant differences were noted in the protein and fat contents of the pikeperch livers; these were significantly higher in the groups fed diets supplemented with VO (P < 0.05). The fatty acid (FA) profiles of the pikeperch body parts (whole fish, fillets, viscera, liver) analyzed reflected the proximate composition of the diets applied. The FA profiles of pikeperch muscles were the most stable. The diets tested did not have a significant impact in the fillets of fish from the VO groups on the value of summed products of polyunsaturated FA from the n-3 family (n-3 PUFA) to the PUFA from the n-6 family (n-6 PUFA) (n-3/n-6 ratio) (P > 0.05). They were, however, significantly lower than the values noted in group CD (P < 0.05) (1.03-2.07 vs. 3.50). Wpływ żywienia juwenalnego sandacza (Sander lucioperca (L.)) paszami suplementowanymi olejami roślinnymi na podstawowy skład chemiczny ciała i profile kwasów tłuszczowych Młdocianego sandacza (początkowa masa ciała ok. 100 g) podchowywano w obiegach recyrkulacyjnych przez 55 dni i żywiono komercyjną paszą pstrągową (grupa CD) lub paszami suplementowanymi następującymi olejami roślinnymi (VO): rzepakowym (grupa RO), sojowym (grupa SO) lub słonecznikowym (grupa SFO). Poziom suplementacji pasz VO wynosił 84% całkowitego tłuszczu surowego (CF) - do komercyjnej mieszanki bazowej zawierającej 30 g CF kg-1 paszy dodawano 160 g VO kg-1 paszy. Podstawowy skład chemiczny pasz był podobny, a profile kwasów tłuszczowych (FA) w nich zawartych odzwierciedlały skład chemiczny olejów, którymi były suplementowane (tabela 1). Żywienie testowanymi paszami nie wpłynęło istotnie na wartości wskaźników wzrostu ryb i podstawowy skład chemiczny całej ryby, filetów i trzewi (P > 0,05; tabela 2). Odnotowano natomiast istotne różnice w zawartości białka i tłuszczu w wątrobie sandacza. Stwierdzono, że zawartość białka w grupach RO i SO była istotnie niższa niż u ryb z grup CD i SFO (P < 0,05). Poziom tłuszczu w wątrobie ryb z grup VO był wyższy od stwierdzonego w grupie CD, a w przypadku grup RO i SO różnice te były istotne statystycznie (P < 0,05; tabela 2). Profile FA analizowanych części ciała sandacza (cała ryba, filet, trzewia i wątroba) odzwierciedlały skład chemiczny stosowanych pasz (tabela 1, 3, 4, 5, 6). Udział wszystkich analizowanych grup FA, tj. nasyconych (SFA), nienasyconych (USFA), monoenowych (MUFA), polienowych (PUFA), polienowych z rodziny n-3 (n-3 PUFA) i polienowych z rodziny n-6 (n-6 PUFA) w całym ciele, trzewiach i wątrobie był istotnie determinowany stosowaną dietą (P < 0,05; tabela 3, 5, 6). Najbardziej stabilny był skład FA mięśni sandacza (tabela 4). W filetach ryb z grup VO nie stwierdzono istotnego wpływu żywienia testowanymi paszami na wartości ilorazów n-3 PUFA do n-6 PUFA (stosunek n-3/n-6) (P > 0,05). Były one jednak istotnie niższe niż w grupie CD (P < 0,05) (1,03-2,07 vs 3,50).