Effects of Dietary Detarium microcarpum Stem-bark Extract on Erythrocyte and Leucocyte Variables in Nile Tilapia (Oreochromis niloticus)
Bazoma Bayili
Western Regional Directorate for Environmental and Agricultural Research (DRREA-Ouest), Institute of Environment and Agricultural Research (INERA), National Centre for Scientific and Technological Research (CNRST), 01 BP 910, Bobo-Dioulasso 01, Burkina Faso.
Aïcha Edith Soara
Centre for Environmental and Agricultural Research and Training (CREAF), Institute of Environment and Agricultural Research (INERA), National Centre for Scientific and Technological Research (CNRST), 03 BP 7047, Ouagadougou 03, Burkina Faso.
Sévérin N’Do *
Western Regional Directorate, Health Sciences Research Institute (IRSS-DRO), National Centre for Scientific and Technological Research (CNRST), 01 BP 545, Bobo-Dioulasso 01, Burkina Faso.
Sayouba Ouedraogo
National School of Livestock and Animal Health (ENESA), 01 BP 7026, Ouagadougou 01, Burkina Faso.
Wicehan Marie Madeleine Ouattara
Institute of Rural Development (IDR), Nazi BONI University (UNB), 01 BP 1091, Bobo-Dioulasso 01, Burkina Faso.
Bali Jean Bazié
Institute of Sciences and Techniques (INSTech), 01 BP 2779, Bobo-Dioulasso 01, Burkina Faso.
Marcelin Zingué
Medical Analysis Laboratory, Center for Welfare, Counseling and Care for the Elderly (CAES), Sector 18 (Kuinima), Bobo-Dioulasso, Burkina Faso.
*Author to whom correspondence should be addressed.
Abstract
Plant-derived feed additives are increasingly investigated as locally available tools for sustainable aquaculture, but their physiological effects require careful assessment. The objective was to determine whether graded dietary supplementation with a hydroethanolic Detarium microcarpum stem-bark extract was associated with detectable changes in erythrocyte and leucocyte variables in Nile tilapia (Oreochromis niloticus). A 90-day completely randomised feeding trial was conducted in Loumbila, Burkina Faso, with haematological analyses performed in Bobo-Dioulasso in 2026. A total of 180 fingerlings (initial body weight 7.49 ± 1.43 g) were allocated to 12 tanks (15 fish/tank) and fed an unsupplemented control diet (RT) or diets containing 200, 300, or 400 mg dried extract/kg feed (R1, R2, and R3, respectively), with three replicate tanks per treatment. After 90 days, three fish per tank (n = 9/treatment) were sampled. Red and white blood cell counts, haemoglobin, haematocrit, erythrocyte indices, lymphocytes, and neutrophils were measured using a Sysmex XN-550 analyser, and dietary effects were assessed by nested analysis of variance. No significant dietary effect was detected for any of the nine haematological variables; treatment-effect P values ranged from .10 to .80. Red blood cell counts ranged from 1.37 ± 0.51 to 1.84 ± 0.52 ×10⁶/µL, haemoglobin from 7.17 ± 2.47 to 9.62 ± 2.62 g/dL, and haematocrit from 23.00 ± 7.10 to 30.96 ± 9.40%. White blood cells and lymphocytes were numerically highest in R2 but showed substantial within-treatment variability, while mean neutrophil-to-lymphocyte ratios remained descriptively similar (0.214-0.270). Under the conditions tested, dietary D. microcarpum stem-bark extract at 200-400 mg/kg did not produce a detectable adverse haematological effect. The numerical leucocyte changes do not establish immunostimulation and require confirmation using validated fish-specific cell-counting methods and complementary immune biomarkers.
Keywords: Detarium microcarpum, Oreochromis niloticus, haematology, hydroethanolic extract, phytogenic feed additive, dietary supplementation