Performance of ROSS 308 broilers on maize-sprouted cowpeas grower-finisher diets fortified with black soldier fly (hermatia illucens) larvae meal

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.