Effects of dietary Adansonia digitata L. (baobab) seed meal on growth performance and carcass characteristics of broiler chickens: A systematic review and meta-analysis

Abstract

Abstract The seeds of lesser-known tropical legume trees are currently being promoted as a cost-effective method of increasing broiler productivity, especially in low- and middle-income countries. Several feeding trials have evaluated the effects of baobab seed meal (BSM) on broiler chicken productivity. However, due to differences in experimental conditions among feeding trials, drawing broad conclusions using this large volume of data appears difficult. Thus, the meta-analytic effect of BSM on growth performance [i.e., feed intake, feed conversion ratio (FCR), and body weight gain (BWG)] and carcass characteristics of broilers were investigated using 14 peer-reviewed published articles. These articles were retrieved via a systematic search conducted on Google Scholar, ScienceDirect, Elicit.com, and PubMed databases. The effect size was calculated via a random effect model, and results were expressed as standardised mean differences (SMD) at 95% confidence intervals. The pooled results showed that broilers fed BSM had significantly lower BWG (SMD = −0.77; −0.19, −0.30; p < 0.001), dressed carcass weight (SMD = −0.84; −1.44, −0.23; p = 0.007), and higher FCR (SMD = 0.55; 0.19, 0.91; p < 0.001) than those fed control diets. However, feed intake, dressing percentage, and weights of breast, thigh, and drumstick were not significantly affected. Subgroup analyses showed that the Marshall strain-fed BSM-based diets had significantly heavier BWG (p < 0.001) than the Hubbard, Ross, and Anak strains. Similarly, results revealed that broilers fed soaked and roasted BSM had significantly better FCR and BWG than broilers fed sundried and fermented BSM. Broilers fed BSM-based diets from days 29–56 (SMD = 0.17; −0.51, 0.84; p = 0.622) and days 1−56 (SMD = −0.89; −1.41, −0.36; p < 0.001) had significantly improved FCR compared to those offered BSM-based diets from days 1–21 (SMD = 2.58; 1.65, 3.51; p < 0.001), days 1–28 (SMD = 0.85; 0.35, 1.34; p < 0.001), and days 22–42 (SMD = 1.82; 1.02, 2.62; p < 0.001). Similarly, broilers fed BSM-based diets from days 29–56 (SMD = 0.21; −0.38, 0.79; p = 0.484) and days 1−56 (SMD = 0.92; 0.16, 1.69; p = 0.018) had significantly higher BWG than those offered BSM-based diets from days 1–21 (SMD = −3.39; −4.41, −2.37; p < 0.001), days 1–28 (SMD = −1.32; −1.91, −0.72; p < 0.001), and days 22–42 (SMD = −2.24; −2.75, 1.73; p < 0.001). Meta-regression revealed a low to moderate effect of processing methods, broiler strains, inclusion level, and feeding duration as covariates, explaining most of the sources of heterogeneity. In conclusion, broilers fed 1–10% of soaked, and roasted BSM from days 1 to 56 had improved growth performance parameters when compared to those on the control.