摘要Background Maternal nutrition is essential in keeping a highly efficient production system in the pig industry.Lami-narin has been shown to improve antioxidant capacity,reduce the inflammatory response,and favor the homeostasis of intestinal microbiota.However,the effect of dietary supplementation of laminarin on the reproductive perfor-mance of sows and the growth of suckling offspring remains unknown.Methods A total of 40 Landrace × Yorkshire multiparous sows on d 85 of gestation,similar in age,body weight(BW),parity and reproductive performance,were randomly divided into four dietary treatments with 10 sows per treat-ment,receiving a control diet(basal pregnancy or lactating diets)and a basal diet supplemented with 0.025％,0.05％and 0.10％laminarin,respectively.The experiment lasted from d 85 of gestation to d 21 of lactation.Results Laminarin supplementation linearly increased number born alive per litter(P=0.03),average daily feed intake(ADFI,P＜0.01),and total milk yield of sows during the lactation of 1-21 d(P=0.02).Furthermore,maternal laminarin supplementation increased the average daily gain(ADG)of piglets while tending to reduce the culling and death rate before weaning.In addition,alterations to the composition of colostrum and milk,as well as to serum infllammatory cytokines and immunoglobulins of sows were observed.The fecal microbiota profile of sows supported the improvement of reproductive performance in sows and the growth performance in suckling offspring.Conclusions Dietary supplementation of laminarin during late pregnancy and lactation could significantly improve reproductive performance of sows and growth performance of piglets.