Vpliv maščobnokislinske sestave iker na embrionalni razvoj lipana (Thymallus thymallus)

Koglar, Karin (avtor), Sušnik Bajec, Simona (mentor), Levart, Alenka (komentor)

Lipan (Thymallus thymallus) je salmonidna vrsta rib, ki ga v naravnem okolju ogrožajo številni dejavniki, zato so populacije v upadanju. Ovira pri vzreji v ribogojnicah je zelo velik pogin med embrionalnim razvojem. Eden od pomembnih dejavnikov, ki vplivajo na kakovost iker, je njihova maščobnokislinska (MK) sestava. V okviru naloge smo ugotavljali vpliv MK sestave iker na njihovo kakovost, ki smo jo ovrednotili preko oplojenosti, valilnosti in prisotnosti deformacij. V poskus smo vključili ikre samic lipana s treh lokacij v naravi in dveh ribogojnic. Za ikre in larvice prostoživečih samic smo v primerjavi z ikrami in larvicami ribogojniških samic ugotovili, da imajo višjo valilnost in višjo stopnjo preživetja, glede na časovni potek embrionalnega razvoja pa je srce zarodkov začelo biti kasneje, prav tako so prve larvice za izvalitev potrebovale več časa. Med MK, ki vplivajo na embrionalni razvoj, ikre ribogojniških samic vsebujejo več LA in DHA, ikre prostoživečih samic pa več ARA in EPA. Razmerje DHA/EPA je višje pri ikrah ribogojniških samic. Potrdili smo vpliv razmerja DHA/EPA na embrionalni razvoj; razmerje DHA/EPA v ikrah je v negativni korelaciji z valilnostjo larvic. Ikre ribogojniških samic vsebujejo več MK in tudi več večkrat nenasičenih maščobnih kislin (PUFA) kot ikre prostoživečih samic. Naši rezultati nakazujejo, da je vsebnost PUFA v ikrah v negativni korelaciji z valilnostjo. Deformirane larvice imajo v primerjavi s pravilno razvitimi larvicami več linolne in adrenične kisline, ki lahko vplivata na razvoj hrbtenice. Ugotovili smo: (1) MK sestava iker se razlikuje glede na izvor samic (prostoživeče, ribogojniške) in je odvisna od prehrane samic; (2) pri zarodkih iz iker z višjim razmerjem DHA/EPA je pogin višji.

• Jezik: Slovenski jezik
• Ključne besede: ribogojstvo, ribe, lipan, Thymallus thymallus, reprodukcija, ikre, zarodki, maščobnokislinska sestava
• Vrsta gradiva: Magistrsko delo/naloga
• Tipologija: 2.09 - Magistrsko delo
• Organizacija: BF - Biotehniška fakulteta
• Leto izida: 2024
• PID: 20.500.12556/RUL-165305
• COBISS.SI-ID: 217836291
• Datum objave v RUL: 01.12.2024

KOGLAR, Karin, 2024, Vpliv maščobnokislinske sestave iker na embrionalni razvoj lipana (Thymallus thymallus) [na spletu]. Magistrsko delo. [Dostopano 11 april 2025]. Pridobljeno s: https://repozitorij.uni-lj.si/IzpisGradiva.php?lang=slv&id=165305

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: The effect of the egg fatty acid composition on the embryonic development of grayling (Thymallus thymallus)

Izvleček

The grayling (Thymallus thymallus) is a salmonid species that is threatened in its natural environment by a number of factors. One obstacle to breeding is the very high mortality rate during embryonic development. One of the most important factors affecting egg quality is the composition of fatty acids (FA). In this work, we investigated the influence of the FA composition of the egg on egg quality, which was evaluated by the fertilisation rate, hatching rate and the incidence of malformations. Eggs from female grayling from three wild stocks and two farms were included in the experiment. Compared to eggs and larvae from farmed females, eggs and larvae from wild females were found to have higher hatchability, higher survival rates, and, in terms of the timing of embryonic development, the embryonic heartbeat started later and the first larvae took longer to hatch. Of the FAs affecting embryonic development, eggs from farmed females contain more LA and DHA, while eggs from wild females contain more ARA and EPA. The DHA/EPA ratio is higher in the eggs of farmed females. We confirmed the influence of the DHA/EPA ratio on embryonic development; DHA/EPA ratio in eggs is negatively correlated with the hatching rate. Eggs from farmed females contain more FA and also more polyunsaturated fatty acids (PUFA) than eggs from wild females. Our results indicate that the mass fraction of PUFA in eggs is negatively correlated with hatching rate. Deformed larvae contain more linoleic acid and adrenic acid compared to well-developed larvae, which may influence spine development. We found that: (1) FA composition of eggs varies according to female origin (wild, farmed) and depends on female diet; (2) embryos from eggs with higher DHA/EPA ratio have higher mortality rate.

• Ključne besede: aquaculture, fish, grayling, Thymallus thymallus, reproduction, eggs, embryos, fatty acid composition