The determination of nutrient requirements and development of artificial diets for the mass rearing of insects of economic importance

Thesis (MScAgric)--Stellenbosch University, 2017.

ENGLISH ABSTRACT: The mass production of various insect species for biocontrol methods and as feed and food is becoming common practice and several different rearing facilities have been established across the world. Although insect mass production facilities have been set in place, the mass production of insects is still in an infantile stage and research is necessary to optimize these systems. As with conventional intensive livestock production the success of these systems, as well as the costs implicated, can largely be contributed to the nutrition of the animals. The false codling moth (FCM) (Thaumatotibia leucotreta), black soldier fly (BSF) (Hermetia illucens) and yellow mealworm (mealworm) (Tenebrio Molitor) are species currently being mass reared and are of economic importance. Three separate experiments were conducted to study the nutritional needs and formulate artificial diets for the mentioned species. It was believed that the current diet used to mass produce the FCM did not meet the requirements of the insects and that it led to nutrient imbalances, and therefore optimal production could not occur. Diets were formulated with novel raw materials and processing methods determined based on various methods. The newly formulated diet led to a ~55% increase in productivity. Current practice for the mass rearing of the BSF involves rearing the insects on chicken layer mash for the first six days of their life cycle, also referred to as the nursery phase. It was once again believed that the nutrient composition of the layer mash in no way resembled the nutrient needs of the larvae and a nursery diet was developed using the comparative slaughter technique. The newly formulated nursery diet led to a ~25% increase in survivability of the neonatal larvae during the nursery period. The protein requirement of mealworms was also studied. Plant (soya bean meal) and animal (ground beef) protein sources at different inclusion levels were tested. The inclusion of ground beef led to a ~50% increase in pupation rate of the mealworm larvae which implied a decrease in production time needed to rear the mealworm and an increase in production efficiency. Overall the results obtained from the different studies were a step in the right direction to understand the nutritional needs of the insect species studied and to solidify the mass rearing of insects for biocontrol methods as well as for feed and food.

AFRIKAANSE OPSOMMING: Die grootskaalse produksie van verskillende insekspesies vir die doel van biologiese beheer en as voer en voedsel raak algemene praktyk. ‘n Verskeidenheid produksie eenhede is al reeds gevestig reg oor die wêreld. Alhoewel grootskaalse eenhede alreeds in plek gestel is, is die grootskaalse produksie van insekte nog in ‘n aanvangs fase. Navorsing word benodig sodat hierdie eenhede hul produksie potensiaal kan bereik. Soos in die geval met intensiewe produksie van vee speel voeding ‘n groot rol in die sukses sowel as die koste van die produksie van insekte. Die vals kodling mot (VKM) (Thaumatotibia leucotreta), venstervlieg (VV) (Hermetia illucens) en geel meelwurm (meelwurm) (Tenebrio Molitor) is insek spesies waarmee reeds grootskaals geboer word en wat ekonomiese waarde het. Drie verskillende proewe is uitgevoer om die nutrient-behoeftes van die bostaande insekte te bepaal sowel as om voere te formuleer vir die grootskaalse produksie van hierdie spesies. Daar is geglo dat die huidige voer wat gebruik word om die VKM te produseer nie voldoen aan die nutrient-behoeftes van die larwes nie, wat lei tot nutrient wanbalans en afname in produksie. Voere is geformuleer met nuwe rou materiale en die gaarmaak metodes van die nuwe voer bepaal. Die nuwe geformuleerde voere het ‘n ~55% toename in die produksie van die VKM tot gevolg gehad. Met die produksie van die VV maak huidige metodes gebruik van lê-hen meel om die larwes groot te maak vir die eerste ses dae van hul lewensiklus. Dit was weereens geglo dat die nutrientsamestelling van die lê-hen meel nie aan die behoeftes van die larwes voldoen nie en nuwe voere is geformuleer deur gebruik te maak van die vergelykende slag tegniek. Die nuwe voer het ‘n ~25% toename in oorleefbaarheid van die VV larwes tot gevolg gehad gedurende hierdie fase. Die proteïen-behoefte van meelwurms was ook ondersoek. ‘n Plantproteïen (sojaboon meel) en dierlike proteïen bron (gemaalde beesvleis) teen verskillende insluitingsvlakke is getoets in die dieet van meelwurms. Die gebruik van gemaalde beesvleis as proteïenbron was gemik om die toekomstige moontliheid van die insluiting van slagpale- afval in die dieet van meelwurms te evalueer. Die insluiting van gemaalde beesvleis het ‘n ~50% toename in die tempo van papie wording tot gevolg gehad wat impliseer dat produksie effektiwiteit verdubbel het. Algeheel was die resultate van die proewe ‘n stap in die regte rigting vir die grootskaalse produksie van insekte en het dit meer insig geskep oor die nutriëntbehoeftes van die insekte wat nagevors was.

Masters