BackgroundLinoleic acid (LA) is predominantly essential for poultry. Deficiency of LA in poultry were manifested in various aspects such as retarded growth and reduced resistance to disease. The effects of LA on intestinal health in vitro and in mammals has been studied, whereas research related to the effects of LA on intestine health in poultry was scanty. Intestinal health and immune function play an important role in pigeon squab growth. Considering squabs are fed by their parents, the purpose of this study was to explore the effects of maternal dietary LA on intestinal barrier function in squabs by determining intestinal morphology, gene expression of tight junction protein, immune cytokines, and microbial flora.ResultsA completely randomized design with a control group, 1% dietary LA supplementation group, 2% dietary LA supplementation group, and 4% dietary LA supplementation group was used. Six squabs from each treatment were randomly sampled at 21 posthatch. Results indicated that LA supplementation improved intestinal morphology as reflected by increased villus height, villus area and the ratio of villus to crypt, and the promotion at dosage of 1% was most significant. Besides, 1% LA supplementation elevated distribution density of goblet cell in intestine, and strengthened tight junction between enterocytes by up-regulating claudin3 and occludin gene expression, but down-regulating claudin2 gene expression. Moreover, 1% LA supplementation reduced secretion of pro-inflammation cytokines and increased anti-inflammation cytokines partly. The diversity index Chao1 of intestinal microbiota in 1% LA supplementation group was higher than other groups. And Butyrivibrio as beneficial bacteria was the biomarker of LA1%. However, excessive (4%) LA supplementation led to adverse impact on intestinal immunity and microbiota.ConclusionsMaternal dietary LA in three levels all could improve intestinal morphology in squabs. Therein, appropriate dosage (1%) supplementation might enhance mucosal protection and epithelium barrieer in squabs, and furthermore consolidated intestine immunity and luminal microbial environment. However, excessive (4%) LA supplementation might lead to adverse impact on immunity and microbiota. Maternal dietary LA might alter intestinal barrier function in pigeon squabs in a dose-dependent manner.