Development of an Insect-based Encapsulated Feed for Shrimp Aquaculture
The aim of this thesis was to create an innovative shrimp aquafeed with encapsulation technology and varying concentrations of mealworm meal to improve the sustainability of current shrimp aquaculture production. This feed was developed and tested on a non-commercial shrimp species (Palaemon affinis) as a proxy for application of shrimp aquaculture. Laboratory analyses and feeding trials were conducted to compare the encapsulated feed with a commercial feed for P. affinis growth parameters, feed sustainability and effect on water quality parameters. The results indicate that the encapsulated feed had significantly less matrix erosion over 48 hours in seawater than the commercial feed. Additionally, an eight-week feeding trial was conducted to assess the effectiveness of the encapsulated mealworm diets on shrimp. Four diets were used in the feeding trial: a commercial diet (CF) with predominantly fishmeal as the protein source and three encapsulated mealworm diets with varying concentrations of fishmeal: mealworm ratios (F70, F50 and F30). The final weight and length displayed significant differences in shrimp fed higher concentrations of mealworm meal (F50, F30). However, it was discovered that there was a correlation between the weight gain of shrimp and the lipid concentration in the diets suggesting that the weight gain was due to the increased lipids in mealworms rather than the diets themselves. Uniquely, shrimp fed F50 were found to excrete excess lipids in their diets, resulting in no significant difference in bodily lipids in comparison to the lower concentration of mealworm diets. This suggests that shrimp fed slightly elevated levels of lipids than required may be able to discard the excess lipids in their faecal matter. Additionally, feed utilisation, feed ingested, palatability and survival all indicated no significant differences between commercial and encapsulated diets. Overall, the results indicate that an encapsulated mealworm diet can be utilised to enhance water quality parameters in shrimp aquaculture and indicate that alternative, sustainable insect-based protein sources such as mealworms have the potential to replace fishmeal in varying concentrations.