Weining is located in southwest China at an average altitude of 2,200 meters. It is a large livestock county where cattle raising is the main economic income of farmers. In 2021, the stock of cattle in Weining was 153,600, accounting for 6.5% of the local agricultural output, with the most farmed species being Weining cattle and Angus cattle. The Weining cattle are an ancient ruminant with hypoxia tolerance, anti-oxidant action, and disease resistance, and have become the symbol of Weining Guizhou. They resemble ordinary cows with short horns and yellow hair, but also have many characteristics of their own. Due to the nutritious quality of their meat, their strength, and their docility, Weining play a significant role in local farming and prosperity. In addition, the incidence of intestinal diseases is fairly low compared to other types of cattle, one of the most important reasons for local people keeping Weining cattle.

The normal intestine harbors over 100 trillion microorganisms including bacteria (98%), fungi (0.1%), viruses, protists, archaea, and these microbial communities (Liu J. et al., 2019; Li et al., 2021). The gut microbiota colonizing the intestinal tract forms a symbiotic relationship with the host and plays a vital role in maintaining nutrient intake, immune regulation, and intestinal barrier integrity. In addition, the gut microbiome is believed to be a biochemical transformation that exerts beneficial substances such as antimicrobial peptides, vitamins, and enzymes. Increasing evidence suggests that the diversity and composition of the gut microbiome have been linked to species and health, with species being the primary cause of the gut microbiota, followed by health status. However, to date, knowledge of the gut microbiota characteristics of Weining and Angus cattle is limited.

As is well known, diarrhea occurs in all animals, especially in newborns, and causes death in about half of the ruminants (Li et al., 2018; Bu et al., 2020). Calf mortality due to diarrhea remains very high in most countries, e.g., 17% in Germany and 5% in the United States (Urie et al., 2018; Eibl et al., 2021). Several studies have also indicated that intestinal microbial dysbiosis drives the development of diarrhea (Han et al., 2017; Shao et al., 2020). Healthy and balanced intestinal flora reduce the risk of diarrhea (Huang et al., 2019; Zuo et al., 2021). Previous studies have shown that intestinal bacteria in some ruminants alternate between dominant and weak populations with diarrheal symptoms (Yang et al., 2017). Thus, there may be some unavoidable links between the alteration of intestinal microbial communities and diarrhea. In the last few years, we have found that other types of cattle like Angus were more susceptible to diarrhea in Weining China. The mortality rate of other types of cattle was 9%, whereas in Weining cattle it was 3%. However, so far, there is little information about the relationship between diarrhea and gut microbiota in Angus cattle.

Regarding this phenomenon, we speculated about whether the low incidence of diarrhea in Weining cattle was related to intestinal flora. Possible reasons are that the Weining cattle’s ancestors lived in relative isolation after entering the mountains and developed individual gut flora. However, the characteristics of gut microbiota in Weining cattle remain unclear. Here we seek to investigate and compare the composition and variability of gut bacteria in Weining cattle (WN), healthy Angus cattle (An), and diarrheal Angus cattle (DA). In addition, although there have been recent studies on gut microbiota and diarrhea, very few studies have been conducted on Angus cattle, and our study aims to better understand how gut microbes affect organismal health, exploring potential pathogenic microbes. Meanwhile, we aimed to explore the potential bacteria associated with disease resistance. These findings will aid in the future development of dietary interventions that may resolve or prevent enteric and diarrheal diseases in ruminants.

Diarrhea is the most common disease in calves and severely affects the animal’s growth and development. According to previous reports, the economic damage caused by diarrhea is enormous and difficult to control (Fischer et al., 2016; Lorenz et al., 2021). Studies indicated that the etiology of bovine diarrhea is multifactorial, with pathogens and management factors (housing, feeding, and sanitary conditions) playing an important role (Bendali et al., 1999). A study in diarrheal calves in Belgium estimated the prevalence of E. coliRotavirus, Coronavirus, and C. parvum at 4, 20, 8, and 31%, respectively. In a recent Swiss study on diarrheal calves, the prevalence of these Enteropathogens remained at high levels. Moreover, diarrhea inevitably accompanies intestinal damage, suggesting that the intestinal microbiota may be altered (Xia et al., 2018; Zhai et al., 2019). As the habitat of intestinal flora, the gastrointestinal tract is more susceptible to various diseases such as inflammatory bowel disease and diarrhea due to the influence of intestinal flora (Liu C. S. et al., 2019; Yue et al., 2019; Zhang et al., 2022). In addition, although the gut microbiota inhabits the gut, significant changes in the gut microbiota may also lead to the development of other diseases such as liver disease, diabetes, and obesity, etc. (Guo et al., 2022; Ye et al., 2022). More importantly, significant changes in gut microbiota also affect gut permeability, which may lead to a leaky gut and increased rates of pathogenic bacterial infection (Yue et al., 2020; Xu et al., 2021). Therefore, the characterization of gut microbiota is crucial for the prevention, control, and diagnosis of diarrhea (Bjorkman et al., 2003; Singh et al., 2015).

Gut microbial diversity and richness constantly decrease under the influence of diarrhea (Zhang L. et al., 2020; Cui et al., 2021; Ren et al., 2022). In our study, we found no significant difference in gut microbiota diversity and richness between the An group and DA group, the lack of difference is most likely due to an increase in pathogenic bacteria due to diarrhea and a decrease in beneficial bacteria in the DA group. In Han’s report, there was no significant difference in gut microbial diversity between healthy and diarrheal yaks, which was consistent with our findings (Han et al., 2017). Similarly, He′s results are also similar to ours: diarrhea does not significantly alter the diversity and richness of gut microbiota in pigs (He et al., 2020). Although the diversity and richness of intestinal microbiota did not change significantly, the composition of bacteria did. Anaerosporbacter were rich in the DA group but were not detected in the An group. Anaerosporbacter is likely to be associated with the occurrence of colorectal cancer. In Yu’s study, the results manifested that the Anaerosporbacter were abundant in the colorectal cancer group compared to the healthy group (Yu et al., 2017). Campylobacter is recognized as the most common cause of bacterial enteritis (Liu et al., 2018). Among bacterial infections reported in recent years, Campylobacter spp. predominated. In Singh’s report, Campylobacter usually causes asymptomatic infections, diarrhea, and hemorrhagic colitis (Singh et al., 2015; Shin et al., 2021). Interestingly, the aforementioned potentially pathogenic bacteria exhibited a significant relative abundance in the DA group compared to the An group. Candidatus Soleaferrea secretes homeostatic protective properties and has anti-inflammatory effects (Zhang et al., 2015), there was no significant difference in the proportion of Candidatus Soleaferrea in the An and DA groups. Conversely, the beneficial bacteria including Dorea, Muribaculaceae, UCG-009, and Monoglobus were significantly lower in the DA group compared with healthy Angus cattle. Monoglobus is a beneficial bacteria that modulates the metabolism (Kim et al., 2019). Unique among known human gut flora, Monoglobus plays an active role in pectin degradation and sugar utilization (Kim et al., 2019). Muribaculaceae can produce propionate, which is closely related to gut health. Related studies have reported that Muribaculaceae are closely related to acarbose consumption (Smith et al., 2021). In addition, Dorea and UCG-009 are capable of regulating health and absorbing nutrients. In the current study, the gut microbiota of Angus cattle with diarrhea was significantly altered, implying an imbalance in gut homeostasis. Our study showed that gut microbiota dysbiosis is an important factor driving the development of diarrhea. At the same time, the findings shed light on potential pathogens including Anaerosporbacter and Campylobacter, which cause diarrhea in Angus cattle.

It is well known that gut microbiota are an important indicator for evaluating gut function and homeostasis (Xia et al., 2018; Duan et al., 2020; Reese et al., 2021). However, the diversity of gut microbiota is easily affected by various factors such as species, age, and various diseases (Ding et al., 2019; Wu et al., 2020, 2022). Species are the most important factor affecting gut microbiota (Yang et al., 2018; Huang et al., 2020; Zhong et al., 2021). Animals of various species need to evolve different intestinal flora structures to adapt to their habitats, and diet characteristics, etc. (Liu et al., 2021, 2022). For example, herbivores have a higher intestinal flora structure to digest cellulose and realize energy conversion (Dong et al., 2020; Yang et al., 2022). In addition, different breeds of sheep and chickens also have different intestinal flora structures (Rettedal et al., 2019; Qin et al., 2020). Captive horses, for example, have lower gut microbiota composition and lower numbers of pathogenic bacteria than wild donkeys (Zhou et al., 2022). In addition, compared with cattle living in plain areas, yaks need to evolve a more diverse intestinal flora structure to adapt to the high-altitude hypoxic environment of the Qinghai-Tibet Plateau (Fu et al., 2021; Wang et al., 2021). Intestinal flora are executors of intestinal function and the supervisor of intestinal health, so changes in intestinal flora also affect the health of the host (Yin et al., 2019; Zhang P. et al., 2020; Chen et al., 2022).

Weining cattle are a native breed in Guizhou, while Angus cattle are an exotic breed introduced to Weining in the last 10 years. Weining cattle and Angus cattle are currently the main breeds in Weining Guizhou, occupying more than 90% of the local cattle industry. In the past 3 years, the incidence of diarrhea was less than 3% in Weining cattle. However, the rate of diarrhea in other breeds of cattle was significantly higher than 5%. Previous studies have demonstrated that the gut microbiome is correlated with species and health. In some studies, greater quantities of Firmicutes were found in the WN group compared to the An groups. Previous research has reported that Firmicutes are closely related to the health of gut microbiota (Eckburg et al., 2005), which contribute to maintaining gut microbiota balance, regulating the gut environment, and inhibiting pathogens (Sun et al., 2016). In addition, Lachnospiraceae, Rikenellaceae, and Coprostanoligenes were the most dominant genus in the WN group. Lachnospiraceae is closely linked to host health by producing short-chain fatty acids, converting primary to secondary bile acids, and inhibiting intestinal pathogens (Sorbara et al., 2020). The Rikenellaceae and Coprostanoligenes were regarded as a beneficial bacterium in modulating health and serum dyslipidemia (Tavella et al., 2021). Rikenellaceae plays an essential role in maintaining intestinal mucosal immunity, Previous studies have demonstrated that HIV infection is distinctly involved with the loss of Rikenellaceae (Dubourg et al., 2017). Similarly, in Teresa Tavella’s research, Rikenellaceae could significantly reduce visceral adipose tissue and help maintain a healthier metabolic profile, which proved that adequate Rikenellaceae could improve the body’s health and metabolism (Backhed et al., 2015; Dubin et al., 2016). Meanwhile, Wei et al. (2021) reported that Coprostanoligenes have the ability to modulate serum dyslipidemia. Overall, the highest abundance of beneficial bacteria was present in the WN group compared to the An and DA groups. In particular, the Lachnospiraceae are over-represented in Weining cattle, showing significantly higher abundances compared to Angus cattle. Interestingly, the Muribaculaceae, which plays an important role in anti-inflammatory action was also enriched in the WN group. Conversely, the potential pathogens including Alistipes and Campylobacteria were lower present in the WN group compared to the An group. Overall, the greater abundance and diversity of beneficial bacteria indicated the potential of Weining cattle for diarrhea prevention and health modulation. The data revealed that a good gut microbiome structure improves the body’s disease resistance and health status. In addition, Weining cattle have great potential as an isolated source of probiotics.

This study characterized the gut microbiota diversity and composition in Weining cattle and Angus cattle. The WN group had a greater abundance of beneficial bacteria and a lower abundance of potential pathogens. While there was no significant difference between healthy Angus and diarrheal Angus, there was a significant change in the type and proportion of bacteria. The potential pathogens including Anaerosporbacter and Campylobacter were higher in diarrheal cattle, conversely, the beneficial bacteria including Dorea, Muribaculaceae, UCG-009, and Monoglobus were significantly lower compared to healthy cattle. This is the first report of gut microbiota in Weining cattle and broadens the knowledge of gut microbiota. Our results convey the message that diarrhea not only directly modifies the diversity and abundance of gut microbiota but also indirectly affects some functional bacteria. In addition, this study revealed potentially pathogenic bacteria and provided basic data for the subsequent treatment of diarrhea in Angus cattle.

The datasets presented in this study can be found in online repositories. The names of the repository/repositories and accession number(s) can be found at: https://www.ncbi.nlm.nih.gov/, PRJNA931445.

The study was conducted under the guidance and approval of the Animal Welfare and Ethics Committee of Huazhong Agricultural University.

LW, JM, and MW provided the research idea. DW, JM, and MW contributed reagents, materials, and analysis tools. LW wrote the manuscript. KL and YZ revised the manuscript. All authors participated in writing and reviewing the manuscript, contributed to the article and approved the submitted version.

The study was supported by Research and Demonstration of Key Technology for Nutritional Control and Efficient Utilization of Roughage for Weining Cattle [Guizhou Science (2021) General project No. 153], the Weining Cattle Breeding Base of Weining County, Guizhou Province, and the Sixth Batch of Talent Base Project of Guizhou Province [Guizhou people Hair Collar (2018) No. 3].

The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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