Feeding of Different Levels of Synbiotics to Suckling Lambs: Effects on Intake, Digestibility, Performance, Parameters of Rumen, Blood and Health, and Skeletal Growth.

Abstract

The study aimed to investigate the effects of varying levels of synbiotics (combinations of probiotics and prebiotics) on the performance and health parameters of 28 Afshari lambs over a period of 90 days. The average weight of lambs was of 10 ± 0.2 kg and an age of approximately 1 month. The prebiotic supplement included mannan oligosaccharide and beta-glucan from Saccharomyces cerevisiae yeast, along with a probiotic comprising seven bacterial strains, and used at concentration of 2 × 109/g cfu. A 2 × 2 factorial design was employed in a completely randomized design, with the factors being the levels of probiotic supplementation (1.0 g and 2.0 g) and prebiotic supplementation (1.5 g and 3.0 g). The interaction effect of probiotic and prebiotic was significant on dry matter intake (p < 0.01), digestibility (p < 0.01), total white blood cell (p < 0.05) and Improved feed conversion ratio (p < 0.01). These effects were higher at treatment of high levels of probiotic (2 grams) and prebiotic (3 grams). The higher levels of probiotic significantly influenced on biometric parameters such as heart girth and withers height (p < 0.01 and p < 0.01, respectively). Higher levels of probiotic and prebiotic supplementation had a positive impact on total white blood cell, and monocytes counts. The high level of synbiotic supplementation resulted in a significant increase in total blood protein concentration and glucose levels, with the differences being statistically significant at p < 0.05 and p < 0.01, respectively. Additionally, the decrease in ruminal NH₃-N concentration with higher level probiotic compare to low level (8.69 vs 7.08 mg/dl) indicates improved rumen nitrogen utilization and potentially better rumen health. Overall, these findings highlight the potential of high levels of synbiotics to improve growth performance, nutrient digestion, and health outcomes in suckling lambs.