J. ADENIYI AGUNBIADE1, OLAJIDE A. ADEYEMI2, OLUWAKEMI R. IDOWU1, OLUSOLA A. AJAYI3, H. AKANJI AWOJOBI1, OLUWASEYI. O. ENIOLORUNDA1
1Olabisi Onabanjo University, Department of Animal Production, Nigeria
2University of Agriculture, Animal Production and Health, Nigeria
3University of Agriculture, Department of Veterinary Pathology, Nigeria
The potential of earthworm meal (EWM) as a source of dietary protein for poultry was evaluated. EWM protein replaced fish meal (FM) protein at 0 to 100% in diets based on soyabean meal (SBM) as major plant protein source and fish meal (FM) as animal source.
Six iso-energetic (13.34 - 13.63MJ/kg) and iso"=nitrogenous (237.3 - 247.6g/kg) diets were evaluated with broiler chickens between age one and four weeks. The diets comprised the control diet (Diet 1) with SBM as main protein source and diets 2 - 6 having either SBM and FM (Diet 2) or a combination of SBM, FM and/or EWM (Diets 3 - 6) as protein source. Taking the protein supplied by FM in diet 2 as 100%, FM and EWM were combined in other diets to supply: 75:25 (Diet 3), 50:50 (Diet 4); 25:75 (diet 5); 0:100% protein (Diet 6). A completely randomised design was employed in which birds were randomly allocated to five replicate groups of four birds per treatment. A nutrient retention trial was conducted in the last week of the experiment.
Results indicate that EWM is rich in nutrients; 670g/kg protein, 60g/kg ether extract, 881.2g/kg dry matter (DM) and 18.2MJ/kg gross energy (GE).
Birds on the basal diet ate significantly (p < 0.05) less feed than those on other diets. Diets in which 25 and 100% EWM replaced FM had similar rate (22.5, 24.04 vs 24.8g/day) and efficiency (2.25, 2.08 vs 2.02) of daily weight gain compared with diet 2 having 100% FM protein. Nitrogen retention (NR) and digestibility of crude fibre and fat of basal diet, diets 2 and 3 were significantly (p < 0.05) higher than those of other diets. NR (63.8%), DM (72.8%) and ash (24.4%) digestibility of diet in which EWM completely replaced FM were the poorest.
Histopathological results revealed normal organs for the basal diet while the other diets revealed multiple foci of bile duct hyperplasia. This study indicates that EWM with a microbial count of 2.5 x 105CFU/ml appears a wholesome protein source and could completely replace FM in diets for broiler starters.
Keywords: Broiler starter, earthworm meal, growth rate, histopathology, Nigeria, nutrient retention, protein source