Effects of partial and total substitution of fish meal with corn gluten meal on growth performance, nutrients utilization and some blood constituents of the Nile tilapia Oreochromis niloticus

The present study was conducted to evaluate partial or total substitution of fish
meal with corn gluten meal and its effects on growth performance, nutrients
utilization and blood characteristics of fingerling tilapia. Four isonitrogenous diets
were formulated to contain (30.16±0.08 Crude protein) with different inclusion levels
(D0, D50, D75 and D100% corn gluten meal). Fish were fed on on the artificial diets
at a rate of 3% of the fish biomass daily divided into two equal portions. Fingerlings
tilapia with an initial weight of 6.65±0.2g were distributed in concrete tanks as 225
juveniles in each triplicate tank of 9m3 volume to represent 4 dietary treatments in
triplicates. The experimental period lasted 105 days after start. The results showed
significant differences (P<0.05) in growth performance and feed conversion ratio
between diets. The highest performance in terms of (final weight, weight gain,
average daily gain, specific growth rate, condition factor, feed conversion ratio,
protein efficiency ratio, and protein productive value and Hepatosomatic index) were
obtained with the C0, C50 and C50%, respectively, without significance difference
between them. The inclusion of 100% corn gluten meal showed significant
differences (P<0.05) with decreased growth performance and feed efficiency
compared to the other tested diets. No significance difference (P<0.05) in whole body
chemical composition (dry matter, crude protein, crude lipid and ash) was observed
between fish fed on on all experimental diets. The blood parameters did not vary
significantly by dietary treatments. The results of the present study indicated that, the
inclusion of up to 75% corn gluten meal level as low cost plant protein instead of fish
meal can be utilized in tilapia diets without adverse effects on growth performance,
feed efficiency and blood characteristics.