Optimization of protease-treated Black Soldier Fly Larvae (BSFL) using Response Surface Methodology (RSM) for broiler feed

Insects have been recognized as a potential source of protein for both human food and animal feed. Hermelia illucens or commonly known as black soldier fly larvae (BSFL) are a type of insect that can feed and develop on a wide range of feed sources such as on kitchen waste, dairy manure, chicken manure as well as human feces. This insect has been used as an alternative protein source for a lot of animal feeding including fisheries and poultry. However, the digestive system of animals is not fully efficient. Thus, animals including broiler usually would not be able to fully digest all sources of nutrient upon consuming the feed. Most of the time, nutrient especially protein is being wasted through the animal's manure. Therefore, it is important to find an effective way to improve protein absorption of BSFL so that broiler will be able to completely digest all of the nutrients from the feed formulation. In order to overcome this problem, protease was produced and used to treat the BSFL so that protein in the BSFL can be converted into amino acids, thus improving broiler's nutrient absorption. In this study, the optimum condition for obtaining the highest decrease in protein content (%) of the BSFL was being investigated by using Response Surface Methodology (RSM). A model of Central Composite Design (CCD) with three variables: volume of water (5-8 mL), volume of protease (100-300 µL) and time of incubation (30-90 min) were used to study the response variable which was the decrease in protein content (%). From this study, the protein content of the BSFL before and after the treatment was able to be identified and compared by performing protein analysis. The data analysis generated by Design Expert Software version 11 showed that the model is significant at p < 0.05 which affected the response variable. The effect of the variables and parameters was studied by using a 2D counter plot and 3D response surface graph. The software suggested that the optimum conditions were 5 mL of water, 100 of protease and 30 minutes of incubation time for treating the BSFL in order to obtain 10.5266% decrease in the protein content.