Abstract:
Tilapia is an important freshwater species in global aquaculture, but rising
commercial feed costs have reduced its economic viability. Black soldier fly
larval (BSFL) meal offers a cost-effective, protein-rich alternative that can
lower feed expenses and increase the profit by utilizing food waste for
production. The objective of the present study is to evaluate BSFL meal as an
alternative protein source for tilapia growth and to assess its economic impact
in Sri Lanka. A 42-day feeding trial was conducted using a completely
randomized design to evaluate the effectiveness of BSFL meal as a protein
substitute in tilapia diets. The study included four treatment groups, each
conducted in duplicate, a control group fed 100% commercial feed, and three
experimental groups fed diets containing 50, 75, and 100% BSFL based feed,
respectively. Each tank was stocked with 10 tilapia fries of uniform size, with a
mean initial body weight of 27 ± 2 g and a mean initial total length of
9.5 ± 0.5 cm. Fish growth performance was assessed through measurements of
length, weight gain, and feed conversion ratio (FCR), while feed cost was
analyzed to determine economic viability. The final average length (cm) of
tilapia was recorded as 11.28±0.37, 11.40±0.59, 11.12±0.38, 11.01±0.50 in
control, treatment 1, treatment 2 and treatment 3, respectively. In terms of final
average weight (g) the results were 52.55±5.93, 51.20±3.68, 49.15±3.26,
45.56±2.24 in control, treatment 1, treatment 2 and treatment 3, respectively.
Fish weight and length differed significantly among the feeding groups (P<
0.05), as determined by ANOVA. However, Tukey’s HSD post-hoc test
revealed a statistically significant difference in weight (P< 0.05) only between
the control group and the 100% BSFL group (Treatment 3). The average FCR
for the control, treatment 1, treatment 2, and treatment 3 groups was
1.20 ± 0.21, 1.27 ± 0.22, 1.36 ± 0.29, and 1.46 ± 0.14, respectively. There were
no statistically significant differences in FCR between the ccontrol group and
any of the treatment groups. Increasing the inclusion level of BSFL meal
reduced the feed cost to two-thirds of the original cost. This study concludes
that BSFL meal can replace up to 75% of commercial feed, without negatively
impacting growth performance or feed efficiency. No significant differences
were observed in key growth parameters, and feed costs were substantially
reduced. Thus, BSFL meal can be used a viable, cost-effective alternative
protein source in tilapia feed.
