Evaluation of novel climate-friendly feed for Nile tilapia in Tanzania

Sammanfattning: Tanzania is a country located in sub-Sahara Africa by the Indian Ocean. Tanzania's aquaculture sector is small but has the potential to grow. As the population grows, so does the demand for food. Nile tilapia is the most cultured fish in Tanzania due to its hardiness, fast growth and tolerance to many environmental conditions. Fish meal (FM) and soybean meal has traditionally been used as a protein source in fish feed. However, insects have been proposed as potential alternative protein sources to replace FM and soybean meal, which are expensive and negatively affects the environment and feed and food security. One of these insects is the black soldier fly (BSF) due to its high content of amino acids, lipids, vitamins and minerals. The objective of the current study is to examine and assess how a locally produced feed containing BSF meal will affect the growth performance of Nile tilapia. Physical feed quality and chemical composition were also evaluated. In addition, the environmental impact of using BSF larvae in tilapia feed was also evaluated by calculating the greenhouse gas (GHG) emissions from such a feed production system. The BSF diet was compared to a Control and commercially used diet at fish farms in Tanzania. Results show that growth performance could not be statistically evaluated due to variation in the different ponds used during the fish growth experiment. Nutritional composition and the chemical score showed low histidine, lysine, and methionine and a high phenylalanine content in the BSF meal compared to the FM. Physical feed quality showed that the BSF diet had the best water stability compared to other diets used in the experiment. However, the BSF diet had lower durability and hardness. GHG calculations showed that the BSF diet had the lowest emission of GHG.