Abstract:
The objectives of the study were to evaluate the efficacy of sprouted cowpea (Vigna unguiculata)-
maize (Zea mays) grower and finisher broiler diets, and of 5%, versus 10% fortification of the diets
with full-fat Black Soldier fly (Hermatia illucens) larvae meal (BSFLM). The trial used 360 -day-old
Ross 308 broiler chicks reared in an open, deep litter house. Chicks were placed in 30 wire mesh
experimental pens of 150 cm length × 144 cm width. Chicks were uniformly managed during the
starter (21 days) phase, feeding on a commercial starter. The chicks received supplementary
stress vitamins (Virbac© Samrand Business Park, Centurion, Pretoria, South Africa) during days
1-6. On day-22, sexed broilers were randomly allotted at 12 birds per pen in a 5 (diet) X 2 (sex)
factorial arrangement with three replications per treatment. Grower phase (days 22-35) and
finisher phase (days 36-42) dietary treatments were: 0% BSFLM sprouted cowpea negative
control (NC) diets, positive control (PC) commercial diets, low (LF 5% BSFLM) and high (HF 5%
BSFLM) fat sprouted cowpea diets with 5% BSFLM diets, and 10% BSFLM sprouted cowpea
diets. Feed intake (FI), body weight gain (BWG), feed conversion ratio (FCR) and mortality rates
were measured on a weekly basis. Upon slaughter, the weight of the warm dressed carcass,
carcass components, visceral organs and abdominal fat were measured while meat quality (pH,
drip loss and meat colour) were evaluated. During the grower phase, broilers on the PC
consumed more (p<0.05) feed and achieved higher weight gain (p<0.05) than those on the NC
and LF 5% BSFLM diets. The PC birds achieved lower (p<0.05) FCR compared to broilers on the
NC and HF 5% BSFLM. During the finisher phase, broilers on the PC consumed more (p<0.05)
feed than those on the 10% BSFLM diet. Cumulatively throughout the grower-finisher phases,
broilers on the PC had higher feed intake and weight gain (p<0.05) than on the NC and HF 5%
BSFLM diets and attained higher (p<0.05) final live weight with lower (p<0.05) FCR compared to
broilers on the NC. Male broilers consumed more (p<0.05) feed during the grower phase and by
slaughter, with higher p<0.05) weight gain during finishing, which resulted in heavier (p<0.05) live
weight at slaughter. There was no (p>0.05) sex * diet interaction on parameters for measuring
the growth performance. Broilers on the PC had larger (p<0.05) breast weights compared to birds
on the NC and the 10% BSFLM diets and had higher (p<0.05) thigh weights than those on all
other treatments. Broilers on the PC had a larger (p<0.05) spleen than birds on the NC and the
5% BSFLM diets. The females had lower thigh and liver weights compared to the males
(p<0.050). Birds on the 10% BSFLM had lower drip loss compared to those on the negative
control (p<0.05). In conclusion, broilers fed the sprouted cowpea-maize diet without BSFLM had
low feed intake, weight gain and high FCR during the growing phase, and these effects were
vi
cumulatively reflected at slaughter. Compared to the NC and PC diets, BSFLM fortification of
sprouted cowpea-maize diets resulted in intermediate parameters for broiler growth performance.
Based on the growth performance, it was concluded that dietary efficacy was in the order NC <5
% LF<5% HF< 10 % BSFLM < PC fortification.