Physical testing on formulated earthworm-based pellets for growth performance evaluation in African Catfish (Clarias gariepinus)
Abstract
New formulation of fish pellets was designed by using earthworm powder and other
economical ingredients such as soybean waste, rice bran and tapioca starch as an alternative protein source for substitution of fishmeal due to the worldwide shortage. The formulation
was calculated using Pearson’s square method by dividing ingredients into protein sources
ingredients and energy sources ingredients with higher ration on low cost ingredients. The
optimization of heating process carried out by using One-Factor-at-One-Time (OFAT)
based on the highest water stability. The high water stability (82.14%) was achieved when
heated at 80°C within 40 minutes. Physical properties of producing pellets such as soaking
test, protein leaching test and hardness test were conducted to confirm the applicable of
pellets to fish experimental. Pellets potential was evaluated by determining the growth
performance of African catfish (Clarias gariepinus) fed with heated earthworm-based fish
pellets. Fish experimental was conducted for 8 weeks by comparing weekly weight of the
fish fed with heated earthworm-based pellets and commercial pellets. The growth
performance of heated earthworm-based pellets showed higher weight and length increment
compared to existing commercial pellets. Apparent digestibility tests were also performed
for protein, fat, energy, and dry matter. Heated earthworm-based pellets and commercial
pellets were modified by adding chromic oxide as an inert marker to determine the apparent
digestibility coefficient. The feces of experimented catfish were collected at forth weeks of
fish experimental for the analysis. Digestibility of protein, total fat, gross energy and dry
matter for earthworm-based pellets are 94.92%, 98.09%, 78.53% and 77.78% while
commercial pellets are 66.98%, 98.18%, 74.14% and 71.43% respectively.Introduction of
new formulation and heating process had resulted in growth improvement of the fish by
12.48% from commercial pellets.