Broilers are frequently exposed to various immunological stresses, which lead to intestinal damage, weakened immunity, and even growth retardation. Lutein, as a kind of carotenoid, possesses antioxidant and immunomodulatory functions. Therefore, this study was conducted to investigate the effects of lutein on jejunal mucosal barrier function and inflammatory responses of yellow-feather broilers challenged with lipopolysaccharide (LPS). A total of two hundred eight-eight 1-day-old yellow-feather broilers were randomly allocated to 3 groups with 8 replicate cages containing 12 birds each. Birds were fed broken-rice-soybean basal diet containing 0, 20 and 40 mg/kg lutein (CON, LU20 and LU40) for 26 d. On days 21, 23, and 25 of the trial, broilers were intraperitoneally injected with LPS (1 mg/kg body weight). The results showed that, compared with CON group, LU40 supplementations significantly increased the average daily gain (ADG) of broilers at 1 to 21 and 22 to 26 d of age (P < 0.05), significantly decreased the ratio of feed to gain (F/G) of broilers at 22 to 26 d of age (P < 0.05). LU20 and LU40 supplementations increased goblet cell density in jejunum of broilers under LPS challenge, and LU20 supplementation elevated the villus area (P < 0.05). Scanning electron microscopy of jejunal mucosa revealed significant villi damage, while transmission electron microscopy demonstrated severe enterocyte damage and loss of cellular integrity in CON group. In particular, mitochondria were morphologically altered, appearing irregular or swollen. Apical junctional complexes between adjacent enterocytes were obviously shorter and saccular in CON group. LU20 and LU40 supplementations increased the mRNA expressions of Occludin, Claudin-1, and ZO-1 in the jejunal mucosa of broilers under LPS challenge (P < 0.05), restrained TLR4/MyD88/NF-κB pathway activation in the jejunal mucosa, decreased the mRNA expressions of IL-1β and IL-6, and strengthened the mRNA expressions of IL-4 and IL-10 (P < 0.05). Meanwhile, the protein expressions of p38 and JNK in LU40 group were lower than CON group (P < 0.05). It can be concluded that 40 mg/kg lutein supplementation improved LPS-induced jejunal mucosal barrier function and tamed inflammation of yellow-feather broilers.

Astaxanthin (AST), a keto carotenoid, is widely recognized for its antioxidant, anti-inflammatory, and apoptosis-regulating properties, but its effects on intestinal health have not been elucidated. Therefore, this experiment aimed to investigate the effects of astaxanthin on intestinal morphology, barrier function, mucosal immunity, and cecal flora in yellow-feathered broilers, and to explore the potential mechanisms. A total of 288 male yellow-feathered broilers (1-day-old) were randomly allocated to four groups with six replicates of 12 birds each. The control group (CON) was fed a basal diet, the test groups were fed a basal diet added with 20 mg/kg, 40 mg/kg, and 80mg/kg of astaxanthin (AST20, AST40, and AST80), respectively. The results showed that compared with the CON group, the villus height and the villus-to-crypt ratio of broiler jejunum in the astaxanthin-added group increased, while the crypt depth decreased (P < 0.05). In addition, IL-1β content and gene expression in broiler jejunal mucosa decreased, IL-6 gene expression decreased, and IL-4 content and gene expression increased (P < 0.05). The tight junction protein ZO-1 expression level in the jejunum mucosa of broilers was up-regulated, and the content of serum D-lactic acid was decreased (P < 0.05). Besides, the α-diversity and β-diversity analyses showed that astaxanthin regulated both the diversity and the structure of the intestinal flora of broilers. After multiple comparative analyses, the relative abundance of norank_f__Eubacterium_coprostanoligenes_group, Lachnospiraceae NC2004_group, and unclassified_p_Firmicutes increased in the AST20 group compared to the CON group, while that of Ruminococcus_torques_group in the AST80 group decreased (P < 0.05). Therefore, AST can regulate the immune function of broiler intestinal mucosa, improve intestinal morphology and structure, and then influence intestinal permeability. It also has a considerable regulatory effect on the diversity and structure of broiler intestinal flora and plays a multifaceted role in maintaining broiler intestinal health.

The aim of this study was to investigate the effects of mixed organic acids (MOAs) on growth performance, immunity, antioxidants, intestinal digestion, and barrier function in Ira rabbits. A total of 192 weaned male Ira rabbits at 35 days of age were randomly assigned to four groups with six replicates of eight rabbits each. The rabbits in the control group (CON) were fed a basal diet, and the antibiotic group (SAL) was fed a basal diet supplemented with 60 mg/kg salinomycin. The test groups were fed a basal diet supplemented with 1000 mg/kg and 2000 mg/kg MOAs (MOA1 and MOA2, respectively). The experiment lasted for 55 days. The results showed that the ADG of Ira rabbits in the SAL group and MOA1 group was higher than that in the CON group (p < 0.05). The serum IL-6 and liver MDA levels of Ira rabbits in the SAL group, MOA1 group, and MOA2 group were lower than those in the CON group (p < 0.05). In addition, sIgA levels in the jejunal mucosa of Ira rabbits in the SAL group and MOA1 group were increased compared with those in the CON group (p < 0.05). Compared with the CON group, the gene expression of IL-6 was decreased (p < 0.05) in the jejunal mucosa of Ira rabbits in the SAL, MOA1, and MOA2 groups, while the gene expression of IL-1β tended to decrease (p = 0.077) and the IL-10 content tended to increase (p = 0.062). Moreover, the gene expression of ZO-1 in the jejunal mucosa of Ira rabbits was elevated in the MOA1 group compared with the CON group (p < 0.05). In conclusion, dietary supplementation with MOAs can improve growth performance, enhance immune function and antioxidant capacity, and maintain the intestinal barrier in weaned Ira rabbits.

This study evaluated the effects of kaempferol (KAE), and vitamin E (VE) on the performance, reproductive hormones, and the composition of the cecum and uterus microbiota in late-laying hens. A total of 192 49-week-old Jinghong No. 1 laying hens were randomly divided into four groups, with six replicates in each group and eight laying hens in each replicate, pre-reared for one week and formally tested for ten weeks. The CON group was fed basal diets, the VE group, the KAE group, and the KAE + VE group were fed a basal diet to which was added 0.2 g/kg VE, 0.4 g/kg KAE, and 0.2 g/kg VE + 0.4 g/kg KAE, respectively. The results are as follows. Compared to the CON group, the VE group, the KAE group, and the KAE + VE group significantly increased the egg production rate, average daily egg weight and significantly decreased the feed-to-egg ratio. The VE + KAE group significantly improved the Haugh unit. The VE group, the KAE group, and the KAE + VE group considerably enhanced the eggshell strength, eggshell relative weight, eggshell thickness, yolk color, and relative yolk weight. The serum E₂ and LH levels of the KAE group and the KAE + VE group and the serum FSH levels of the KAE + VE group were significantly higher. In the ovary, the KAE group and the KAE + VE group’s ESR1 gene expression levels were significantly higher, and the KAE + VE group’s FSHR gene expression levels were markedly higher. In the uterus, the KAE group and the KAE + VE group’s ESR1 gene expression levels were dramatically higher, and the KAE + VE group’s ESR2 and FSHR gene expression levels were significantly higher. 16S rRNA gene sequencing revealed a significant aggregation of cecum and uterus colonies in the Beta diversity PCoA. In the cecum, Firmicutes, Bacteroidetes, and WPS-2 were the dominant phylums. In the uterus, the Firmicutes, Proteobacteria, and Bacteroidetes were the dominant phylums. The KAE + VE group’s F/B was significantly higher at the phylum level than in the CON group and the VE group. In summary, the addition of VE and KAE to the diet can improve the production performance of late-laying hens, increase the content of reproductive hormones, and stabilize the cecal and uterus microbiota, which may be related to the hormone and microbiota linkage of the gut–uterus axis.

1. This study aimed to investigate effects of dietary fibre and grit on growth performance, gastrointestinal tract development, and gizzard grit retention of geese. 2. The trial had a 3 × 2 factorial design consisting of three levels of dietary crude fibre (CF, 4%, 7% and 10%, adjusted by grass powder), with or without grit addition (1-4 mm river sand). 3. In total, 648, 22-d-old male goslings were randomly allotted to six treatments (six pens/treatment). At 49 d and 70 d of age, one goose per pen was euthanised to collect samples. 4. The birds fed 10% CF had decreased feed conversion ratio (FCR) during 22-49 d, but this effect was less in older geese. Increasing dietary CF levels increased relative weights of gizzards for geese aged 49 d and 70 d. While, grit addition decreased the relative weights of gizzard and duodenum of geese aged 49 d. The gizzard of geese could selectively retain grit from feed even with no grit added. With adequate supply, most grit in gizzard was 0.45-3 mm in size. 5. In conclusion, supplement of CF and grit mainly affected gastrointestinal tract, and the amount of CF affected FCR. Geese aged 22-49 d could utilise dietary CF levels of 4%-7% and older birds could feed on diets with up to 10% CF. The gizzard of goose selectively retained grit of a particle size of 0.45-3mm.