Kalajahu asendamise võimalused jahumardika (Tenebrio molitor) vastsete jahuga vikerforellil
Laen...
Kuupäev
2017
Kättesaadav alates
Autorid
Ajakirja pealkiri
Ajakirja ISSN
Köite pealkiri
Kirjastaja
Eesti Maaülikool
Abstrakt
Maailma kalavarude vähenemise tagajärjel on kalapüügimaht alates 1980. aastast olnud
stabiilne. Jätkuva toidukala kasvava nõudluse rahuldamiseks on hakatud üha enam kalu
kasvatama ning vesiviljeluse jõulise arengu tagajärjel on nõudlus kalajahu- ja õli järele
suur. Uurimustöö eesmärgiks oli hinnata jahumardika (Tenebrio molitor) vastsete baasil
valmistatud sööda sobivust alternatiivse proteiiniallikana vikerforelli maimude söötmisel.
Töö esimeses etapis koguti Eesti vikerforelli kasvatajatelt erinevate vikerforelli söötade
söödaproovid ning võrreldi nende söötade keemilist koostist tootjapoolt väljastatud
andmetega. Jahumardika vastsetest valmistatud pastadest määrati aminohappeline koostis.
Magistritöö peamises etapis viidi Eesti Maaülikooli vesiviljeluse osakonna
retsirkulatsioonisüsteemis läbi söötmiskatse selgitamaks jahumardikate baasil valmistatud
sööda sobivust vikerforelli maimude söötmisel.
Kalakasvandustest kogutud söödaproovide analüüsi tulemus näitas, et toitainete sisaldused
on, valdavalt pisut suuremad kui tooteetiketil märgitud. Jahumardika vastsete pasta
aminohapete sisaldus on sarnane kirjanduses toodud andmetele ning märg pasta sarnaneb
balti kilu aminohappelise koostisega, kuigi lüsiini ja metioniini sisaldused olid väiksemad.
Katses kahe söödaga - kontrollsööt (B1 grupp) ning jahumardika vastsetest valmistatud
sööt (B2 grupp) leiti, et B1 rühma kalade keskmine kehamass oli katse lõpus statistiliselt
oluliselt (p=0,007) suurem, kui B2 rühma kalade kehamass - massid vastavalt 19,39 g ja
16,21 g.
Jahumardika vastsete söötmisvõimaluste selgitamiseks tuleks edasistes uuringutes keskenduda kalajahu osalisele asendamisele jahumardika vastsetega lõheliste söötades.
Lisaks vajab selgitamist selle söötmise mõju kalade kasvukiirusele, ellujäävusele, filee
kvaliteedile ning koostisele.
In consequence of depletion of the world’s fish stock, fishing capacity has stabilized since the 1980s. Fish farming has become increasingly important to fulfil the rising demand for fish. Therefore, due to the rapid growth of the aquaculture sector, demand for fishmeal and fish oil is immense. The aim of this thesis was to assess the suitability of mealworm (Tenebrio molitor) larvae as an alternative to fishmeal used in rainbow trout feeds. The data for this master’s thesis included feed samples from various feed manufacturers for Estonian rainbow trout farmers. The chemical composition of the collected feed samples were compared to the data provided by the manufacturers. In order to determine the amino acid composition of mealworm larvae, a paste of mealworm larvae was analysed. In the second part of the study, a feeding trial with rainbow trout (Oncorhynchus mykiss) was conducted in the recirculation system at the Department of Aquaculture of the Estonian University of Life Sciences. The results of the feed sample analysis showed that the nutrient content in feed is more likely to be higher than stated on the label of the product. The amino acid content of mealworm larvae was similar to the results found in the literature, and the amino acid content of the wet paste of mealworm larvae is similar to the amino acid content of Baltic sprat with the difference of lower lysine and methionine content in the paste. The feeding experiment was conducted with two different feeds: control group (B1 group) fed diets containing fishmeal, and an experimental group (B2 group) fed a diet with mealworm larvae. The mean body weight was significantly greater (p=0.007) in group B1 (19.39 g) compared to group B2 (16.21 g). In conclusion, yellow mealworm larvae have the potential to replace fish meal in diets for rainbow trout fingerling.
In consequence of depletion of the world’s fish stock, fishing capacity has stabilized since the 1980s. Fish farming has become increasingly important to fulfil the rising demand for fish. Therefore, due to the rapid growth of the aquaculture sector, demand for fishmeal and fish oil is immense. The aim of this thesis was to assess the suitability of mealworm (Tenebrio molitor) larvae as an alternative to fishmeal used in rainbow trout feeds. The data for this master’s thesis included feed samples from various feed manufacturers for Estonian rainbow trout farmers. The chemical composition of the collected feed samples were compared to the data provided by the manufacturers. In order to determine the amino acid composition of mealworm larvae, a paste of mealworm larvae was analysed. In the second part of the study, a feeding trial with rainbow trout (Oncorhynchus mykiss) was conducted in the recirculation system at the Department of Aquaculture of the Estonian University of Life Sciences. The results of the feed sample analysis showed that the nutrient content in feed is more likely to be higher than stated on the label of the product. The amino acid content of mealworm larvae was similar to the results found in the literature, and the amino acid content of the wet paste of mealworm larvae is similar to the amino acid content of Baltic sprat with the difference of lower lysine and methionine content in the paste. The feeding experiment was conducted with two different feeds: control group (B1 group) fed diets containing fishmeal, and an experimental group (B2 group) fed a diet with mealworm larvae. The mean body weight was significantly greater (p=0.007) in group B1 (19.39 g) compared to group B2 (16.21 g). In conclusion, yellow mealworm larvae have the potential to replace fish meal in diets for rainbow trout fingerling.
Kirjeldus
Magistritöö
Kalakasvatuse õppekaval
Märksõnad
magistritööd, kalajahu, proteiinid, valgud, söötmine, vikerforell, kasvukiirus