Effect of Inclusion of Black Soldier Fly (Hermetia illucens) Larvae as a Protein Source in Nile Tilapia (Oreochromis niloticus) Diets on Growth Performance, Carcass Nutrient Profile and Profitability

Abstract

Aquaculture is one of the fastest growing sectors in agriculture. This is mainly due to the increase income that increases the demand for animal-source protein resulting from the increasing nutritionally-conscious human population around the world. However, this increase is constrained by the high cost of Fish meal (FM) occasioned by scarcity; a main source of dietary protein in fish feeds. This growing challenge in the production of aquafeeds necessitates the need to consider alternative protein sources that are cheaper, readily available and high nutrient-level. Insect meals have received much attention recently due to their low costs of production, positive impact on the environment, and source of high-quality food and feed protein. Black Soldier Fly (Hermetia illucens) Larvae (BSFL) has been proven to be a sustainable and high-quality source of food and feed protein. Recent studies have shown that BSFL and FM have a nutrient profile that is closely comparable. This study sought to find the effect of replacing FM with BSFL meal in an on-farm setting, to study its influence on growth performance and profitability when farming Nile Tilapia (Oreochromis niloticus, L). The experimental diets formulated consisted of five treatments adhering to the nutritional requirements of Nile Tilapia at different stages of growth and maturation. The treatment groups included: T0 (Control), T25, T50, T75 and T100 in which BSFL meal replaced FM at levels of 0%, 25%, 50%, 75% and 100% respectively. A total of 600 fingerlings were assigned to 20 cages built in an earthen pond (clay soil) of 40m by 20m, with 30 fingerlings in each cage made of Hapa nets, placed in a completely randomized design (CRD) with four replications for each treatment. The fingerlings were fed the experimental diets for 26 weeks and data on their various growth parameters (weight and length) were recorded. The results show that T75 has the highest body weight and length gain compared to all other treatment diets, with statistical differences at (p<0.05) between the treatment groups. The specific growth rate (SGR) was statistically significant (p<0.05) between the treatment groups. The statistical differences between the treatment all reiterate the rejection of the null hypothesis, “there is no significant effect of substituting FM with BSFLM. Treatment T75 recorded the lowest feed conversion ratio (FCR) compared to the other treatments diets. The survival rates from the study were significantly different (p<0.05) with the highest recorded in T75 at 95.83%. Additionally, the increasing levels of BSFL substitution with FM showed reduced feeding costs, which subsequently increased the gross profit margin in the treatment diets. Treatment group T75 showed the highest return on investment (ROI) of 106.9% and cost benefit ratio (CBR) of 2.07 followed by T100 at 83.52% and 1.84 respectively. The study concluded that 75% substitution of FM with BSFLM was the ideal rate of substitution with the best growth performance, highest carcass nutrient composition and highest rate of return on investment in the making of feeds for the production of Nile Tilapia. Key words: Aquaculture, Aquafeeds, BSFL, BSFLM, Nile Tilapia