Hydrolysed insect proteins as fish meal alternatives in the diets of South African abalone (Haliotis midae)

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dc.contributor.advisorVan Zyl, Johan Hendrik Combrinken_ZA
dc.contributor.advisorDe Wet. L. F.en_ZA
dc.contributor.authorVan Schalkwyk, Mighaelen_ZA
dc.contributor.otherStellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.en_ZA
dc.date.accessioned2023-11-28T08:40:00Z
dc.date.accessioned2024-01-08T18:21:56Z
dc.date.available2023-11-28T08:40:00Z
dc.date.available2024-01-08T18:21:56Z
dc.date.issued2023-12
dc.descriptionThesis (MScAgric)--Stellenbosch University, 2023. en_ZA
dc.description.abstractENGLISH ABSTRACT: This research forms part of the global effort towards reduced reliance on fish meal (FM) in aquafeeds. The utilisation of hydrolysed insect protein (HIP) was therefore evaluated against the performance obtained from fish meal-based aquafeed fed to South African abalone. The research presented in this thesis was conducted in three phases and is subsequently presented as such. Phase A evaluated chitin-target hydrolysis through dietary chitinase inclusion within extruded abalone feeds. Chitinase inclusion resulted in significant (P < 0.05) deterioration in water stability (WS). The lowest chitinase inclusion of 0.1% differed significantly (P < 0.05) from the control following 60 min water exposure. A significant reduction in the drying times of the respective treatments was observed. Drying times were correlated with WS and a rapid protocol for WS determination using drying times and drying curves was proposed. However, drying curves did not appear to correlate with WS, but was ascribed to prior drying and prolonged storage of the feeds. Due to the resulting feed disintegration and compromised WS, dietary chitinase inclusion in abalone feeds was not viable. Phase B subsequently evaluated the WS of aquafeeds containing pre-treated hydrolysed insect proteins (HIP), produced via hydrolysis by endogenous (autolysis), or chitinase or amylase enzymes. The respective HIPs were used to replace 20, 40, 60, 80 and 100% of the FM component. A significant (P < 0.05) deterioration in the WS of the amylase and chitinase treatments compared to the control was observed following 360 min WS. Hydrolysed insect protein inclusion resulted in a significant, linear reduction in WS, with 80 and 100% FM replacement (11% and 14% inclusion respectively) yielding significantly (P < 0.05) lower WS compared to the FM control. Moreover, the high HIP amylase treatment consistently yielded lower WS compared to that of the control and chitinase treatments. Despite the significant reduction, the WS of the feeds was determined suitable for a growth-trial. Phase C consisted of a commercial trial to evaluate the growth performance obtained from the respective diets. Eight baskets, stocked with 50 abalone (90 ± 10 g). Moreover, three individual abalone from each basket were tagged with a marked research tag to allow for individual weight and length measurements. No significant differences were observed for any of the measured production parameters between the respective enzymes. Similarly, HIP inclusion had no significant effect on the measured growth parameters. However, the final individual weight of the control treatment was significantly (P < 0.05) lower compared to all other treatments, but similar to the 100% HIP treatment. Dry matter feed intake significantly (P < 0.05) increased with increased HIP inclusions, however, FCR remained largely unaffected, with only the HIP60 treatment significantly (P < 0.05) higher compared to the control. Processing parameters were significantly influenced by the respective enzymes, with the dressing % of amylase treatment yielding the highest visceral weight and percentage. Enzymatic hydrolysis significantly (P < 0.05) increased the brining loss, although canning and cooking resulted in no significant differences in marketable yield. Marketable yield remained unaffected by HIP inclusion, despite a significant reduction in meat mass index with increased HIP inclusions. This study concludes that hydrolysed insect protein is a viable alternative for FM within the diets of South African abalone. The results can contribute towards reduced dependency on FM produced from wild-caught fishers and increase the sustainability of the local abalone industry.en_ZA
dc.description.abstractAFRIKAANSE OPSOMMING: Die navorsing omskryf in hierdie tesis vorm deel van ‘n wêreldwye poging tot volhoubaarheid en poog om verminderde vismeel-afhanklikheid binne die akwakultuur-sektor te bewerkstellig. Die gebruik van gehidroliseerde insekproteïn is as ‘n plaasvervanger vir vismeel in die diëte van Suid- Afrikaanse perlemoen evalueer. Die navorsing was uitgevoer in drie fases, en word gevolglik so aangebied. Gedurende fase A is chitien-geteikende hidrolise deur middel van chitienase insluiting in ge- ekstrudeerde perlemoenvoere evalueer. Die insluiting van chitienase het tot ‘n beduidende verswakking in die waterstabiliteit van al die proefvoere gelei. Die laagste chitienase-insluiting van 0.1% het betekenisvol (P < 0.05) verskil teenoor die kontrole dieet na 60 minute waterblootstelling. ‘n Beduidende vermindering in drogingstyd met toenemende chitienase insluting was waargeneem en gevolglik was ‘n model vir die bepaling van waterstabiliteit deur middel van drogingskurwes voorgestel. Dit blyk egter dat die vooraf droging en die langtermyn stoor van die proef-voere voor analise die drogingstempo en gevolglike drogingskurwes van die proefvoere beïnvloed het, wat die interpretasie van die resultate bemoeilik. As gevolg van ‘n verswakking in waterstabiliteit is chitienase insluiting in perlemoenvoere nie moontlik nie. Gevolglik is chitien-geteikende hidrolise deur middel van die voorbereiding van ‘n insekprotein- hidrolisaat evalueer (fase B). Twee hidrolisate, naamlik ‘n chitienase en amilase behandelde hidrolisate, is getoets teenoor ‘n outilisaat van dieselfde insekmeel (HIP). Die onderskeie hidrolisate is gebruik om 20, 40, 60, 80 en 100% van die vismeel komponent in ‘n perlemoen dieët te vervang. Water-stabiltieits toetse is op die proefvoere gedoen. Daar was gevind dat beide ensiem behandelde hidrolisate tot ‘n beduidende afname in water stabiltiet gelei het in vergelyking met die kontrole, na 360 minute in seewater. Hierdie verswakking in waterstabiliteit is toegeskryf aan die moontlik teenwoordigheid van oorblywende aktiewe ensieme en word verder ondersteun deur die waargenome laer water stabiliteit van die hoë insekmeel ensiem voere in vergelyking met die outoliese voere. Bevestiging van die hipotese kon egter nie binne die raamwerk van die huidige studie bevestig word nie. Die insluiting van HIP het egter ook tot ‘n betekenisvolle (P < 0.05) verswakking in stabiliteit gelei. Beide die 80 en 100% HIP diëte het beduidend van die kontrole verskil. Ten spyte van ‘n verswakking in WS, is die voere steeds as geskik vir ‘n komersiële groeiproef beskou. Fase C het dus dieselfde proefvoere van fase B in ‘n ses-maande groei proef evalueer. Agt mandjies, elk met 50 perlemoene (90 ± 10g) per behandeling is vir die proef gebruik. Drie perlemoene per mandjie is met ‘n merker gemerk om individuele groei te bepaal. Geen beduidende verskille vir enige van die produksie parameters is tussen die onderskeie ensieme waargeneem nie. Behalwe vir finale massa van die individuele diere, waar die kontrole dieëte die laagste liggaamsmassa gehad het, was daar geen betekenisvolle groeiverskille tussen die verskeie HIP insluitings vlakke nie. Droë materiaal voerinname het betekenisvol (P < 0.05) toegeneem met ‘n toenemende vervanging van vismeel. Die toename kon aan swakker waterstabiliteit toegeskryf word. Voeromsetting was grotendeels egter nie deur die hoër voerinname beïnvloed nie, waar slegs die 60HIP betekenisvol (P < 0.05) van die kontrole verskil het. Beide ensiem en HIP het die uitslag- en prosseserings parameters van die preofdiere betekenisvol beïnvloed. Ensiem behandelde HIP het die soutings- en waterverliesse betekenisvol (P < 0.05) verswak, maar die verskille het egter verdwyn tydens die kook en verblikkings prosesse. Geen verskille in die bemarkbare finale produk is dus waargeneem nie. Insekmeelinsluiting het ‘n soortgelyke effek op die uitslag persentasie gehad, en gelei tot ‘n betekenisvolle (P < 0.05) afname in soutings verliese. Hierdie verskille was nogmaals verwyder tydens die verblikkings prosses. Hierdie studie het bevestig dat gehidroliseerde insekproteïn as ‘n geskikte alternatief vir vismeel in perlemoendiete kan dien. Addisionele ensiembehandeling van die verskeie hidrolisate blyk om nie nodig te wees nie, wat tot ‘n kostebesparing vir perlemoenprodusente kan lei. Hierdie navorsing dra by tot die kennis van vismeelalternatiewe en die verminderde vismeel-afhanklikeid en verbeterde volhoubaarheid van die akwakultuur bedryf.af_ZA
dc.description.versionMastersen_ZA
dc.format.extentxix, 156 pages : illustrations (some color)en_ZA
dc.identifier.urihttps://scholar.sun.ac.za/handle/10019.1/128989
dc.language.isoen_ZAen_ZA
dc.language.isoen_ZAen_ZA
dc.publisherStellenbosch : Stellenbosch Universityen_ZA
dc.rights.holderStellenbosch Universityen_ZA
dc.subject.lcshProteins in animal nutritionen_ZA
dc.subject.lcshFish meal as feed -- Nutritionen_ZA
dc.subject.lcshAbalones -- Feeding and feeds -- South Africaen_ZA
dc.subject.lcshHaliotis midae -- Feeding and feedsen_ZA
dc.subject.lcshChitinaseen_ZA
dc.subject.lcshProtein hydrolysatesen_ZA
dc.subject.lcshWater stabilityen_ZA
dc.subject.lcshAbalones -- Effect of water quality onen_ZA
dc.subject.nameUCTDen_ZA
dc.titleHydrolysed insect proteins as fish meal alternatives in the diets of South African abalone (Haliotis midae)en_ZA
dc.typeThesisen_ZA
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