Ulcerative colitis (UC) is a chronic and recurrent inflammatory disease of the gastrointestinal tract. This study aimed to determine the effect of cathelicidin-related antimicrobial peptide (Cramp) on dextran sulfate sodium (DSS)-induced acute experimental colitis in mice and to investigate the underlying mechanisms. Acute UC was induced in C57BL/6 mice with 3% DSS for 7 days, 4 mg/kg b.w. synthetic Cramp peptide was administrated once daily starting on day 4 of the experimental period. Mice were evaluated for body weight, colon length, colon histopathology, and inflammatory cytokines in colon tissue. Using 16 s rRNA sequencing, the composition structure of gut microbiota was characterized. Metabolomic profiling of the serum was performed. The results showed that DSS treatment significantly induced intestinal damage as reflected by disease activity index, histopathological features, and colon length, while Cramp treatment significantly prevented these trends. Meanwhile, Cramp treatment decreased the levels of inflammatory cytokines in both serum and colonic tissue on DSS-induced colitis. It was also observed that DSS damaged the integrity of the intestinal epithelial barrier, whereas Cramp also played a protective role by attenuating these deteriorated effects. Furthermore, Cramp treatment reversed the oxidative stress by increasing the antioxidant enzymes of GSH-PX and decreasing the oxidant content of MDA. Notably, compared to the DSS group, Cramp treatment significantly elevated the abundance of Verrucomicrobiota at the phylum level. Furthermore, at the genus level, Parasutterella and Mucispirllum abundance was increased significantly in response to Cramp treatment, although Roseburia and Enterorhabdus reduced remarkably. Metabolic pathway analysis of serum metabolomics showed that Cramp intervention can regulate various metabolic pathways such as α-linolenic acid, taurine and hypotaurine, sphingolipid, and arachidonic acid metabolism. The study concluded that Cramp significantly ameliorated DSS-induced colonic injury, colonic inflammation, and intestinal barrier dysfunction in mice. The underlying mechanism is closely related to the metabolic alterations derived from gut microbiota.

Toward the late phase of laying, the production performance of laying hens decreases, egg quality deteriorates, lipid metabolism weakens, and hepatic lipid accumulation is exacerbated. Probiotics as an alternative to antimicrobials have been employed in poultry-related industries. Lactobacillus rhamnosus GG (LGG) is currently the most researched and clinically validated probiotic, showing promising effects in multiple application areas. However, few studies have been conducted on livestock (including poultry) production. Compared with the CON group, the feed conversion ratio (P < 0.01) declined significantly in the LGG group. Eggshell strength (P < 0.001) and eggshell thickness (P < 0.001) were significantly increased by supplementation with LGG in the diet. The height (P < 0.001) and proportion (P < 0.05) of the effective layer and the mammillary knob density (P < 0.01) in the eggshell ultrastructure of the LGG group increased significantly, while the mammillary layer (P < 0.05) and knob width (P < 0.01) decreased significantly. The LGG-treated hens had significantly lower serum concentrations of low-density lipoprotein (P < 0.05), free fatty acids (P < 0.01), and liver triglyceride (P < 0.05) levels than those in the CON group. LGG supplementation significantly decreases the feed conversion ratio, improves eggshell quality by altering the ultrastructure, and improves lipid metabolism in the late laying period.

Bovine viral diarrhea; Pathogen; Clinical symptoms; Morbidity control

为更好了解吉林地区奶牛子宫内膜炎的发病规律以及相关因素,以便科学有效地预防该病,本试验调查了2017-2019年吉林地区奶牛子宫内膜炎发病情况与地区、月份、胎次、产奶量、淘汰率、季节以及牧场饲养管理水平等因素之间的相关性,同时调查了奶牛子宫内膜炎病原菌特点.结果 显示,吉林地区各市区奶牛子宫内膜炎发病率高低不一,舒兰市发病率最高,为60.26％,其次是永吉县47.41％,发病率最低的是吉林市区,发病率为15.88％;从月份统计奶牛子宫内膜炎发病情况看,7～10月份奶牛子宫内膜炎发病率较高,1月份发病率最低,为19.17％;从胎次统计上看,6胎次以上奶牛子宫内膜炎发病率最高,为48.46％;从奶牛产奶量对奶牛子宫内膜炎发病率统计上看,年产牛奶高于7000 kg的奶牛子宫内膜炎发病率明显偏高,达到59.12％;散养奶牛子宫内膜炎发病率(76.40％)明显高于规模化养殖的奶牛发病率(28.78％);牧场饲养管理水平优的奶牛子宫内膜炎发病率(18.73％)明显低于饲养管理水平差的发病率(74.56％);混合感染是奶牛子宫内膜炎主要致病性因素,单一性感染性致病因素主要为大肠杆菌、葡萄球菌以及蜡样芽孢杆菌等.结果 表明,加强饲养管理、优化奶牛种群结构、安全规范处理奶牛产科疾病、合理发挥奶牛生产性能以及科学免疫是奶牛健康养殖的保障.

为科学有效防控奶牛子宫内膜炎,本课题组采集了吉林地区多个奶牛养殖场120头患子宫内膜炎奶牛子宫内容物样本,并对其进行染色、镜检以及生化鉴定.分离出主要致病菌为大肠杆菌、金黄色葡萄球菌、表皮葡萄球菌、链球菌以及蜡样芽胞杆菌,单一感染、双重感染所占比例分别为44.35％和41.74％,三重感染所占比例为13.91％;通过敏感药物筛选头孢噻肟、庆大霉素、环丙沙星、四环素、阿莫西林、恩诺沙星以及氧氟沙星均显示出较好的抑菌效果.以上药物可作为吉林地区奶牛子宫内膜炎治疗的首选药物,科学有效防控该病有利于奶牛养殖业和谐、快速、健康发展.