Browsing by Author "Woods, Michael Josias"

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    Colouring the grey areas of insect mass-production to solidify their use as feed, food and biological control agents
    (Stellenbosch : Stellenbosch University, 2019-12) Woods, Michael Josias; Pieterse, Elsje; Hoffman, Louwrens Christiaan; Conlong, Desmond Edward; Goosen, Neil Jurgens; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.
    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 optimise 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. Trials were conducted to try and establish the nutrient requirements of selected insect species based on the body composition technique, a method commonly used for conventional livestock. Positive results were obtained for all involved insect species and led to an increase in production output, as well as to a decrease in the cost of production. For mass-produced insects to reach their full potential they need to be tailored for their end use. A study was conducted where larvae were reared on a substrate rich in polyunsaturated fatty acids in attempt to manipulate the fatty acids that they deposited into their biomass, and subsequently to evaluate the effect this had on the production and meat quality parameters of the animals the larvae had been fed to. Promising results were observed as an increase in the omega-3 fatty acids were observed in the larval biomass and the same occurred in the meat of the quails the enriched larvae were fed to. Although, the ratio of polyunsaturated- to saturated fatty acids could not be changed. Insect processing is another field that needs attention and the fractionation of insect biomass into protein, fat and chitin can result in significant increase in the margins made both environmentally and economically. An enzymatic fractionation method was developed that resulted in the isolation of protein, fat, and chitin and greater total recoveries were obtained compared to previous studies. The subsequent quantification of the chitin content of insects has also been a problem in the past and based on chitin isolation from crustaceans, a gravimetrical protocol was developed to address this issue. The resulting protocol led to the most repeatable and accurate estimation of the chitin content of insect larvae to date. Overall, the results obtained from the series of studies were a step in the right direction to solidify the mass-production of insects for biocontrol methods as well as for feed and food purposes.
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    The determination of nutrient requirements and development of artificial diets for the mass rearing of insects of economic importance
    (Stellenbosch : Stellenbosch University, 2017-03) Woods, Michael Josias; Pieterse, Elsje; Hoffman, Louwrens C.; Stellenbosch University. Faculty of AgriSciences. Dept. of Animal Science.
    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.
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    Hermetia illucens Larvae Reared on different substrates in broiler quail diets : effect on physicochemical and sensory quality of the quail meat
    (MDPI, 2019-08-02) Cullere, Marco; Woods, Michael Josias; Van Emmenes, Liesel; Pieterse, Elsje; Homan, Louwrens Christiaan; Zotte, Antonella Dalle
    This research aimed at improving the fatty acid (FA) profile of Hermetia illucens larvae (HI) and evaluating the effects of their inclusion in growing broiler quails’ diets on the meat physicochemical quality, including detailed amino acid (AA) and FA profiles, sensory traits, and retail display. HI larvae were reared on two different substrates: layer mash (HI1) and 50:50 layer mash/fish offal (HI2). A total of 300 10-day-old quails were allocated to the three dietary groups (five replicates/each): a soybean meal-based diet was formulated (Control), and two other diets were formulated that included either 10% HI1 or HI2. Quails were fed the experimental diets until slaughter. Diets were formulated to be isonitrogenous and isoenergetic. Breast meat quality was affected by the dietary treatments, which displayed different proximate compositions and AA and FA profiles. Meat physical quality, sensory profile, and retail display remained unaffected for the most part. Overall, results showed that it is possible to improve the FA profile of the HI-fed quails’ meat and thus lipid quality through substrate modulation of the HI’s diet.