A healthy animal intestine hosts a diverse population of bacteria in a symbiotic relationship. These bacteria utilize nutrients in the host’s intestinal environment for growth and reproduction. In return, they assist the host in digesting and metabolizing nutrients, fortifying the intestinal barrier, defending against potential pathogens, and maintaining gut health. Bacterial colonization is a crucial aspect of this interaction between bacteria and the intestine and involves the attachment of bacteria to intestinal mucus or epithelial cells through nonspecific or specific interactions. This process primarily relies on adhesins. The binding of bacterial adhesins to host receptors is a prerequisite for the long-term colonization of bacteria and serves as the foundation for the pathogenicity of pathogenic bacteria. Intervening in the adhesion and colonization of bacteria in animal intestines may offer an effective approach to treating gastrointestinal diseases and preventing pathogenic infections. Therefore, this paper reviews the situation and mechanisms of bacterial colonization, the colonization characteristics of various bacteria, and the factors influencing bacterial colonization. The aim of this study was to serve as a reference for further research on bacteria–gut interactions and improving animal gut health.

This study was conducted to evaluate the impacts of brewer’s grains (BG) on growth performance, apparent nutrient digestibility, immunity, antioxidant capacity, and fecal microbiota of Simmental crossbred cattle and the economic benefits. A completely randomized design was adopted in our study. Twenty-four 15-month-old finishing Simmental crossbred male cattle (body weight, 433.43 ± 32.47 kg) were randomly assigned to three groups: control group (basal diet), 10% BG group (supplemented with 10% BG on a dry matter basis), and 15% BG group (supplemented with 15% BG on a dry matter basis). The trial lasted for 48 days, with serum samples collected on days 24 and 48 and fecal samples collected from days 46 to 48. Diets did not influence the average daily gain, dry matter intake, feed efficiency, and serum antioxidant parameters (p > 0.05). The 15% BG group showed significantly higher acid detergent fiber digestibility (p < 0.01) and elevated serum albumin levels on day 48 (p = 0.047) compared with the control group. As for fecal microbiota, there was a lower Chao index (p = 0.040) and a higher abundance of Romboutsia in the 15% BG group (p = 0.025). Moreover, the feed costs of cattle fell by 9.34% and 14.66% after 10% and 15% BG supplementation, respectively. On the whole, BG supplementation demonstrated no significant effects on growth performance or animal health in finishing cattle. The 15% inclusion level demonstrated the greatest cost reduction potential. We, therefore, recommend adopting 15% BG supplementation as the optimal strategy to enhance economic returns in cattle production systems.

The present study was undertaken to evaluate the impacts of nano-composites of copper and carbon (NCCC) on the intestinal luminal micro-ecosystem and mucosal homeostasis of yellow-feather broilers. A total of two-hundred and forty 1-day-old male yellow-feather broilers were randomly allocated into four groups, each with five replications of twelve birds. The control (CON) group received a corn-soybean basal diet, while the N50, N100, and N200 groups were supplemented with 50, 100, and 200 mg/kg of NCCC in basal diets, respectively. The trial duration was 63 days. The findings demonstrated that there were slight impacts of NCCC addition on the intestinal luminal micro-ecosystem of broilers, with the fecal moisture content in the N100 group being slightly higher on Day 3 in the starter phase (p < 0.05). The cecal microbiota structure also did not obviously change (p > 0.05), in spite of the fall in the relative abundance of the Ruminococcus torques group in the N50 group and norank Clostridia UCG-014 in N200 group (p < 0.05). But for intestinal mucosal homeostasis, NCCC played a crucial part in jejunal morphology, tight junction, immunologic status, and antioxidant capacity. There was linear growth in villus height and a quadratic increase in villus height, crypt depth and their ratio with the increase in NCCC dosage (p < 0.05), and 100 mg/kg NCCC supplementation could intensify the expression of CLDN-3 genes (p < 0.05). In addition, IL-4 and IL-10 linearly increased after NCCC treatment (p < 0.05), along with some irregular changes in sIgA (p < 0.05). In addition, higher jejunal mucosal total antioxidant capacities in N50 and N200 groups were also observed (p < 0.05). Overall, NCCC treatment optimized the intestinal mucosa function of broilers in terms of physical barrier and immune and antioxidant capacities, but exerted subtle influence in the luminal environment of yellow-feather broilers. More precisely, dietary supplementation with 50 mg/kg NCCC is recommended for intestinal homeostasis of broilers.