Effects of dietary supplementation of Thymus vulgaris (Lamiaceae) on reproductive parameters in local Kabir rooster of Cameroon

Background:Feed additives are a group of nutrient and non-nutrient compounds which helps farmers in improving the efficiency of feed utilization and thus reducing the high cost of feed. The current study aimed to determine some reproductive performances of local Kabir rooster fed with diets supplemented with thyme (Thymus vulgaris, Lamiaceae) powder. Materials and Methods: A total of 40kabir chicks were divided into four groups on the basis of the diet. One group (T0) received a basal diet (control),two others received a basal diet supplemented with 0.5% (T5) and 1% (T10) of thyme powder while the fourth (TOxy) received a commercial antibiotic, Oxykel 80 WP (0.5g/L H2O). From the 24 th week old, six roosters of each group were bred with females and eggs were collected and incubated to evaluate fertility and hatchability. At 28 th week, the chickens were weighed; their comb and wattle size measured and they were slaughtered thereafter. Blood was collected for hormonal assessment. Collected sperm was characterized and testes were weighted, their size and volume evaluated. Results: Comb height and comb length as well as wattle length were not affected by the thyme supplementation of the diet. However, roosters fed on thyme, especially at 1% significantly increase (P˂0.05) the serum level of LH (5.51±0.39 mUI/mL) and testosterone (1.21±0.27 mUI/mL). These treatments increased sperm volume and the sperm mass motility (76.67±8.16 %), sperm density (3.93±0.12 %) the percentage of live sperm (94.33±0.52 %) compared to the control diet. the spermatozoa abnormality rate was significantly high in TOxy group (3.75±0.76%) and lowest in T10 (1.08±0.49%). The same observation was recorded with the type of abnormality. Addition of 1% thyme in bird diet increased testes relative weight and volume. Thyme positively affected testes length, width and right testicular shape index. This supplement also significantly increased the fertility rate. Eggs fertilized by semen fromroosters fed diet containing 0.5 and 1% of Thyme showed the highest fertility rate. Conclusion:It could be concluded from this study that Thymus vulgaris could be used in poultry as additive diet to improve reproductive hormone level, semen quality, testes characteristics, fertility and eggs hatchability.