BACKGROUND: Diarrhea is usually observed in newborn Hu lambs, while severe diarrhea may lead to the stunted growth and even death in lambs, necessitating the common practice of antibiotic administration to newborns. In order to explore the application of the effective probiotics and/or prebiotic treatment in animal feed to lessen the recline on antibiotics, 27 newborn of Hu lambs were equally allocated into three groups: control group (Con), probiotics group (Pro) receiving Lactiplantibacillus plantarum N-1 (LPN-1), and synbiotics group (Syn) receiving LPN-1 combined with isomaltose-oligosaccharide (IMO), and raised till 60 days of age. RESULTS: Compared with the Con, the incidence of severe diarrhea was lower in both two treatment groups, accompanied by a significant reduction in terramycin administration frequency (P <
0.05). The daily feed intake in newborns significantly increased after probiotics or synbiotics treatment (P <
0.05), leading to the substantial increment in average daily gain by 48.28% and heart girth (P <
0.05), as well as enhancements in height (P <
0.01) at 60 days of the age in synbiotics treatment group. Applying probiotics and synbiotics exhibited the enhanced rumen weight (P <
0.05), and synbiotics further promoted the spleen development (P <
0.05). The inclusion of probiotics and synbiotics significantly modified the gut microbial composition of Hu lambs (P <
0.01), with an increase in Butyrivibrio proteoclasticus and Pseudoruminococcus massiliensis, which were associated with starch and sucrose metabolism. Additionally, the Syn group exhibited an upsurge in the number of species associated with amino acid metabolism and cellulolysis, as well as the raised short-chain fatty acids levels in the newborn gut (P <
0.05). CONCLUSIONS: This study demonstrated that LPN-1 and IMO had an enhanced effect to improve the growth performance and decrease the reliance on antibiotics by promoting the feed intake, balancing the gut microbiota and increasing the short-chain fatty acids content in Hu lambs.