This study was designed to investigate the effects of fermented feed diets on the growth performance and cecal microbial community in geese, and to e

We investigated the gut–kidney interaction in goslings with gout and tried to decipher the probable mechanisms through which gut dysbiosis leads to t

The current study evaluated the effects of dietary protein and fiber levels on growth performance, gout occurrence, intestinal microbial communities, and immunoregulation in the gut-kidney axis of goslings. A completely randomized 2 × 3 factorial design was adopted with 2 CP levels (180 [18CP] and 220 [22CP] g/kg) and 3 crude fiber (CF) levels (30 [low CF], 50 [mid CF], and 70 [high CF] g/kg). The high CP or low CF diets predisposed the goslings to gout. The high protein diets worsened renal function; serum concentrations of UA and Cr as well as XOD activity in 9-day-old goslings fed 22% CP diets were significantly increased. Although CF levels from 3 to 7% did not directly affect kidney health, increasing CF levels might accelerate the increase of probiotics in the cecum of goslings and withhold maleficent bacteria, alleviating the gut dysbiosis caused by high protein diets. An analysis of the cecal microbiota via 16Sr RNA sequencing revealed that the abundance of Enterococcus in the 22CP group was higher than that in the 18CP group but decreased with increasing CF levels on d 9. The abundance of Lactobacillus increased with increasing CF levels. Additionally, higher serum LPS and proinflammatory cytokine concentrations and upregulated mRNA expression levels in the cecal, tonsil, and kidney tissues indicated that high-protein diets could activate the TLR4/MyD88/NFκB pathway and induce both intestinal and renal inflammation in young goslings. Serum LPS concentrations on d 9 were found to decrease with increasing CF, although altering dietary CF levels did not directly affect the serum immune indices of goslings. In conclusion, the high CP diet exerted a negative effect on gout occurrence, microbial communities, and immunoregulation in the gut-kidney axis of goslings, while appropriately increased dietary fiber levels helped maintain intestinal balance and reduced serum LPS concentration. We propose a diet of 18% CP paired with a 5% CF as the optimal combination for gosling feed.

Firstly, forty-eight 1-day-old goslings were randomly allocated to four groups and were fed diets containing crude protein (CP) at different concentrations: 160, 180, 200, and 220 g/kg in Experiment One. We found a dose-dependent relationship between the dietary protein levels and morbidity of gosling gout. The concentration of serum uric acid (UA), creatinine (Cr), and urea nitrogen (UN), and the activity of xanthine oxidase in the 220CP groups were significantly higher than those in the low-protein diet groups. Beneficial microbes, including Akkermansia, Lactococcus, and Butyricicoccus were enriched in the ceca of healthy goslings, while the microbes Enterococcus, Enterobacteriaceae, and Bacteroides were enriched in those with gout. Then, we explored the effects of fermented feed on gosling gout caused by high-protein diets in Experiment Two. A total of 720 1-day-old goslings were randomly allotted to four experimental groups: CN (162.9 g/kg CP), CNF (167.5 g/kg CP, replacing 50 g/kg of the basal diet with fermented feed), HP (229.7 g/kg CP, a high-protein diet), and HPF (230.7 g/kg CP, replacing 50 g/kg of the high-protein diet with fermented feed). We found that the cumulative incidence of gout increased in the HP group compared with that in the control, but decreased in the HPF group compared to that in the HP group. Similarly, the concentration of serum UA in the HP group was higher than that in the CN group, but decreased in the HPF group. Meanwhile, compared with the HP group, using fermented feed in diets decreased the abundance of Enterococcus in the ceca of goslings, while increasing the abundance of Lactobacillus. These results suggest that appropriate dietary protein levels and the fermented feed supplement might relieve the kidney injury and gut microbiota dysbiosis caused by high-protein diets in the development of gosling gout.

The rumen is a vital organ containing vast amounts of microbes that play a key role in the digestion of nutrients and affect the production performance of ruminants. However, few studies have focused on the characterization of the ruminal microbiota composition and function in cows with long-term difference milk protein concentrations, and the relationship between milk protein concentration and ruminal microbiota remains elusive. In this study, we collected the data of milk protein concentrations of 1,025 Holstein cows for 10 mo on a commercial farm. Based on the milk protein concentrations, 30 cows were selected and divided into three groups (n = 10 per group): low milk protein group (LMP, milk protein concentration < 3.1%), medium milk protein group (MMP, 3.1% ≤ milk protein concentration < 3.4%), and high milk protein group (HMP, milk protein concentration ≥ 3.4%). The ruminal microbiome, metabolome, VFA concentrations and proportions, and amino acid profiles of the three groups were analyzed. The data showed that free amino acid (FAA) levels were lower in the rumen and higher in the plasma of HMP cows (P < 0.05). In addition, lower NH₃ concentrations were observed in the rumen, plasma, and milk of the HMP cows (P < 0.05). Protease activity and isobutyric acid molar proportion in the rumen were lower in the HMP group (P < 0.05). Microbiome analysis showed that HMP cows had lower microbial diversity (represented as Shannon and Simpson indices) than LMP cows. At the genus level, lower relative abundances of Prevotella_1 and Ruminococcaceae_UCG_005 were observed in the HMP group (P < 0.05). At the operational taxonomic unit (OTU) level, a lower relative abundance of OTU3 (Prevotella ruminicola) was observed in the HMP group (P < 0.05). We found that the relative abundances of ruminal Prevotella_1 and OTU3 (Prevotella ruminicola) were negatively correlated with milk protein concentration (P < 0.05). These findings suggested that the cows with long-term high milk protein concentrations had lower microbial diversity and weaker protein degradation ability in the rumen. Furthermore, our observations identified a correlation between the milk protein concentration and ruminal microbiota. This study aimed to assess the ruminal microbiome, metabolome, volatile fatty acid concentrations, and amino acid profiles of Holstein cows with different milk protein concentrations. Previous studies have reported that ruminal microbiota can affect the lactation performance of dairy cows. However, little is known about the composition and function of ruminal microbiota in dairy cows differing in milk protein concentrations. In this study, we collected the milk protein concentrations data of 1,025 Holstein cows for 10 mo on a commercial farm. Three groups of cows (n = 10 per group) with low, medium, and high milk protein concentrations were selected. We found that cows with long-term high milk protein concentrations had lower microbial diversity, relative abundances of specific ruminal microbiota, protease activity, and amino acid concentration in the rumen compared to the cows with long-term low milk protein concentration. Meanwhile, cows with long-term high milk protein concentration showed higher amino acid concentrations in the plasma and lower ammonia levels in rumen, plasma and milk than cows with low milk protein concentration. Our findings revealed the correlation between milk protein concentration and specific ruminal microbiota, and proposed a possibility that ruminal microbiota affected milk protein concentration by altering host amino acid profile.

The current study was conducted to evaluate the effects of different administration routes of bacterial lipopolysaccharide (LPS) on intestinal mucosal morphological, immunological, and microbial barrier functions in goslings. First, we compared intestinal villi morphology of goslings under intraperitoneal or oral LPS treatment through hematoxylin and eosin staining. Then, we determined the signatures of the microbiome in the ileum mucosa of goslings subjected to oral LPS treatment at 0, 2, 4, and 8 mg/kg BW by 16S sequencing, and analyzed the changes in intestinal barrier functions and permeability, levels of LPS in the ileum mucosa, plasma, and liver tissue, and the induced inflammatory response of Toll-like receptor 4 (TLR4). As a result, intraperitoneal LPS injection resulted in a thicker intestinal wall in the ileum within a short time, whereas villus height was less affected; in contrast, oral LPS treatment exerted a stronger influence on villus height but not on intestinal wall thickness. We also found that oral LPS treatment affected the structure of the intestinal microbiome, reflected by changes in the clustering of intestinal microbiota. The average abundance of Muribaculaceae showed an increasing trend with increasing LPS levels, and that of the genus Bacteroides decreased, compared with the control group. In addition, oral LPS treatment with 8 mg/kg BW affected the intestinal epithelial morphology, damage the mucosal immune barrier, downregulated the expression of tight junction proteins, increased circulating D-lactate levels, and stimulated the secretion of various inflammatory mediators and activation of the TLR4/MyD88/NFκB pathway. This study presented the injuries of intestinal mucosal barrier function induced by LPS challenges in goslings and provided a scientific model for searching the novel strategies to attenuate the immunological stress and gut injury caused by LPS.