An evaluation of defatted black soldier fly (Hermetia illucens) larvae as a protein source for broiler chicken diets

Cockcroft, Bridget Lynn (2018-03)

Thesis (MSc)--Stellenbosch University, 2018.

Thesis

ENGLISH ABSTRACT: The growth rate of the chicken meat production industry needs to match or exceed the growth rate of the human population to provide sufficient dietary protein for as many people as possible. Thus, alternative protein sources for animal feed are required to support the increasing demands on existing protein sources. Insect protein has recently been recognised as a potential protein source and feed ingredient for animal production systems. Black soldier fly (Hermetia illucens) larvae is one of the many insect protein sources being researched for its inclusion in fish, pig and poultry diets. Mass-rearing of larvae on various waste substrates acts simultaneously as a waste reduction and protein production system. In the current study, the inclusion of defatted black soldier fly larvae (BSFL) in broiler chicken diets was evaluated. The study compared the inclusion of two different defatted BSFL treatments (namely dry-rendered (DR) and extruded (EX)), to that of a full-fat (FF) BSFL treatment and a control treatment. The protein source utilised in the control was soybean meal. The DR, EX and FF products were included at a 15% level in each of the three-phase treatment diets. The control treatment was found to have the significantly highest tibia bone calcium levels, as well as the most acidic ileal gut environment and heavier gizzards. No signs of gizzard erosion were found for any of the treatments tested. The DR treatment was found to be the least efficient larvae treatment tested. Although it had high intakes towards the end of the 28-day trial, this did not result in an increased growth rate. The digestibility trial DR diet was found to have approximately half the mineral concentrations of the EX treatment and a highly non-bioavailable energy content (AME of 8.84MJ/kg). The EX, DR and FF treatment had very high digestibility coefficients (above 90%) for all nutrients analysed. A microscopic evaluation found the DR treatment to have high levels of heat discolouration, yet no significant heat damage. Nonetheless, it was suggested that the palatability of the treatment may have been affected by the processing technique which may have played a role in the relatively inferior production performance. In contrast, the EX treatment performed relatively well within the production parameters with the highest level of breast meat crude protein. The treatment had the darkest breast meat, however did not fall outside of the parameter’s normal. It also yielded the highest meat calcium levels amongst the treatments. The FF treatment yielded the highest calcium to phosphorus ratio, due to the significantly low phosphorus levels. The FF treatment boasted the highest resistance to bone breakage and was superior to all treatments in terms of average live weight, average daily gain, feed conversion ratio, European production efficiency factor and the protein efficiency ratio. The DR treatment compared well with the control regarding production and carcass parameters with no adverse organ or bone limitations found for the DR treatment inclusion. The FF and EX treatments can both successfully be used as a viable protein source in broiler chicken diets at up to 15% inclusion to improve production efficiency.

AFRIKAANSE OPSOMMING: Die groeikoers van hoendervleisproduksie moet die menslike bevolking se groeikoers ewenaar of oortref om vir soveel mense moontlik voldoende dieetproteïen te voorsien. Alternatiewe proteïenbronne word vir dierevoer benodig om die toenemende eise wat aan bestaande proteïenbronne gestel word, te ondersteun. Insekproteïen is onlangs as ’n potensiële proteïenbron en voerbestanddeel in diereproduksiestelsels erken. Larwes van die venstervlieg (Hermetia illucens) is een van die talle bronne van insekproteïen wat nagevors is vir insluiting in visse, varke en pluimvee se voeding. Larwes wat in massas op verskillende afvalsubstrate grootgemaak word, dien terselfdertyd as ’n stelsel vir afvalvermindering én ’n stelsel vir proteïenproduksie. In hierdie studie is die insluiting van ontvette venstervlieglarwes (BSFL) in braaikuikens se dieet geëvalueer. Die studie het die insluiting van twee verskillende ontvette BSFL-behandelings (naamlik droë ontvetting (DR) en ekstrusie (EX)) met die gebruik van ’n volvet-(FF)-BSFL-behandeling en ’n kontrolebehandeling vergelyk. Die proteïenbron wat in die kontrole gebruik is, was sojameel. Die DR-, EX- en FF-produkte is in elk van die driefase-behandelingsdiëte teen ’n vlak van 15% ingesluit. Die kontrolebehandeling het die beduidend hoogste kalsiumvlakke in die tibia, die mees asidiese ileale ingewandsomgewing en swaarder kroppe gegee. Geen tekens van kroperosie is vir enige van die getoetste behandelings gevind nie. Die DR-behandeling was die mins doeltreffende larwebehandeling wat getoets is. Hoewel inname teen die einde van die 28 dae proeftyd hoog was, het dit nie die groeikoers verhoog nie. Die DR-proefdieet vir verteerbaarheid het nagenoeg die helfte van die mineraalkonsentrasies van die EX-behandeling en ’n hoogs nie-biobeskikbare energieinhoud (AME van 8.84MJ/kg) gehad. Die EX-, DR- en FF-behandelings het vir alle voedingstowwe wat ontleed is ’n uiters hoë verteerbaarheidskoëffisiënt (hoër as 90%) gehad. ’n Mikroskopiese evaluasie het getoon dat die DR-behandeling hoë vlakke van hitteverkleuring gehad het, maar geen betekenisvolle hitteskade nie. Die aanduiding is nietemin dat die verwerkingstegniek moontlik die smaaklikheid van die behandeling beïnvloed het, wat ’n rol kon gespeel het in die relatief swakker produksieprestasie. Daarteenoor het die EX-behandeling relatief goed gepresteer binne die produksieparameters, met die hoogste vlak van borsvleis-ruproteïen. Die behandeling het die donkerste borsvleis gelewer, maar dit het nie buite die parameter se normaal geval nie. Dit het van al die behandelings ook die hoogste vleiskalsiumvlakke gegee. Die FF-behandeling het weens die beduidende lae fosforvlakke die hoogste verhouding van kalsium tot fosfor gegee. Die FF-behandeling het die hoogste weerstand teen beenbreuke gelewer en het alle behandelings getroef wat betref gemiddelde lewende gewig, gemiddelde daaglikse gewigstoename, voeromsettingsverhouding, die Europese produksiedoeltreffendheidsfaktor en die proteïendoeltreffendheidsfaktor. Die DR-behandeling het goed met die kontrole vergelyk wat produksie- en karkasparameters betref, met geen ongunstige orgaan- of beenbeperkings wat vir die DR-behandelingsinsluiting gevind is nie. Die FF- en EX-behandelings kan albei met sukses tot 15%-insluiting gebruik word as ’n lewensvatbare bron van proteïen in braaikuikens se dieet om produksiedoeltreffendheid te verhoog.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/103626
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