Changes in Rumen Bacterial Community Induced by the Dietary Physically Effective Neutral Detergent Fiber Levels in Goat Diets

Effects of the level and source of dietary physically effective fiber on feed intake, nutrient utilization, heat energy, ruminal fermentation, and milk production by Alpine goats

Thirty-two primiparous and 31 multiparous Alpine goats were used to determine influences of diets varying in level and source of forage on performance in early to mid-lactation for 16 wk. Diets consisted of 40%, 50%, 60%, and 70% forage (designated as 40F, 50F, 60F, and 70F, respectively) with 60F and 70F containing coarsely ground grass hay (primarily orchardgrass) and 40F and 50F containing cottonseed hulls, alfalfa pellets, and coarsely ground wheat hay. Diets contained 15.9% to 16.3% crude protein and 37.8%, 42.1%, 53.5%, and 55.4% neutral detergent fiber (NDF) with 10.0%, 15.8%, 50.1%, and 55.5% particle retention on a 19-mm sieve, and 26.1%, 29.6%, 38.3%, and 40.0% physically effective NDF (peNDF) for 40F, 50F, 60F, and 70F, respectively. Dry matter intake (2.71, 2.75, 1.96, and 1.95 kg/d) and milk yield (2.82, 2.71, 2.23, and 2.10 kg/d for 40F, 50F, 60F, and 70F, respectively) were lower (P < 0.05) for the two diets highest in forage. Digestion of organic matter was similar among diets (P > 0.05), but digestibility of NDF was greater (P < 0.05) for 60F and 70F (57.5%, 58.4%, 68.9%, and 72.2% for 40F, 50F, 60F, and 70F, respectively). Diet affected (P < 0.05) milk fat (3.16%, 3.37%, 2.93%, and 2.97%) and protein concentrations (2.62%, 2.69%, 2.58%, and 2.52% for 40F, 50F, 60F, and 70F, respectively). Milk energy yield was greater (P < 0.05) for the two diets lowest in forage (7.51, 7.45, 5.68, and 5.34 MJ/d), although yield relative to dry matter intake was not affected (P > 0.05) by diet and was lower (P < 0.05) for primiparous vs. multiparous goats (2.71 and 3.09 MJ/kg). Ruminal pH and acetate proportion were greater for 60F and 70F than for the other diets and the proportion of butyrate was lower for the two diets highest in fiber. The mean lengths of time spent ruminating, eating, standing, and lying were not affected (P > 0.05) by diet or parity, but many interactions involving diet, period, hour, and parity were significant (P < 0.05). In conclusion, lactational performance of Alpine goats in early to mid-lactation will be constrained with diets high in forage of moderate quality, peNDF content, and large particle size, which appeared related to limited feed intake.

Feeding Astragalus membranaceus Root Improves the Rumen Fermentation Rate in Housed Goats through the Alteration of the Rumen Community Composition

Although Astragalus membranaceus root (AMR) has been noted as an ingredient in ruminant feed, the impacts of AMR feeding on rumen fermentation and the microbial community structure within the rumen are yet to be evaluated. This study investigated the effects of AMR supplementation on rumen fermentation characteristics and microbial community structures in goats. In two sets of feeding experiments, four Japanese native goats were fed AMR (10 g/kg DM/day/head) for three weeks per experiment. The rumen fluid samples were analyzed using high-performance liquid chromatography for fermentation products and next-generation sequencing for microbial analysis. The rumen fluid samples in the second experiment were also subject to an in vitro anaerobic fermentation test. The results indicated a significant modification, with a higher volatile fatty acid (VFA) content in the rumen fluid of goats in the feeding period than before feeding (p < 0.01). The microbial analysis revealed a significant increase in community diversity (p < 0.05) following AMR feeding, and the rumen bacterial community increased in two families belonging to the order Oscillospirales in Firmicutes (p < 0.05). The phylum Verrucomicrobiota was observed to be significantly less abundant after AMR feeding than during the control period (p < 0.05). Notably, the linear discriminant analysis revealed that the families with largely unknown functions in the rumen (Oscillospiraceae, Rikenellaceae, Muribaculaceae, and vadinBB97) were the determinants of the community split between control and AMR feeding. Increased fermentation rate by AMR feeding was also supported by an in vitro culture experiment, which resulted in faster VFA production without affecting methane production in total gas production. The study demonstrated that AMR can significantly facilitate change in the bacterial community structure in the goat rumen involving a shift of the favoring fibrolytic bacteria towards VFA production. The long-term effects of AMR supplementation and its applicability across different ruminant species, with potential benefits for animal health and productivity, should be addressed.

Ruminal microbiota-host crosstalks promote ruminal epithelial development in neonatal lambs with alfalfa hay introduction

Ruminal microbiota is gradually established after birth, while microbiota maturation could be highly diverse because of varied solid dietary accessibility. However, how the ruminal microbiota accreted from postnatal hay diets alters rumen epithelial development, and how this affects animal health remains largely unknown. Here, neonatal lambs were introduced to starchy corn-soybean starter or corn-soybean starter + alfalfa hay (AH) to investigate the influences of early life ruminal microbiome on rumen epithelial development using integrated 16s rRNA sequencing-metagenome-transcriptome approaches. The results showed that AH introduction elevated average daily weight gain, rumen weight and volume, rumen epithelial papillae length, and rumen muscle layer thickness. Meanwhile, the relative abundance of fibrolytic bacteria (Christensenellaceae R-7 group, Prevotellaceae UCG-001, and Succinivibrio), acetate producer (Acetitomaculum and Mitsuokella), and propionate producer Succiniclasticum was increased in the rumen content by AH supplementation (P < 0.05). Moreover, AH introduction decreased the relative abundance of total CAZymes, CBM, and GH and increased the abundance of KO genes related to volatile fatty acid (VFA) generation in the rumen content. AH lambs had a higher relative abundance of Succiniclasticum, Megasphaera, Succinivibrio, and Suttonella (P < 0.05), while a lower relative abundance of Cloacibacillus, Desulfovibrio, Dialister, Intestinimonas, Parabacteroides, and Pseudoscardovia (P < 0.05) in the rumen epithelial samples. Furthermore, these alterations in ruminal microbial structure and function resulted in ruminal epithelial cell proliferation and development pathways activation. In summary, AH introduction benefited ruminal fiber degradation and VFA generation bacteria colonization and promoted ruminal epithelial development. These findings provide new insights into ruminal microbial-host interactions in the early life.IMPORTANCEWhile it is established that a fiber-rich diet promotes rumen development in lambs, further research is needed to investigate the precise response of rumen microbiota and epithelium to high-quality alfalfa hay. Here, we observed that the inclusion of alfalfa hay led to a discernible alteration in the developmental trajectory of the rumen. Notably, there was a favorable shift in the rumen's volume, morphology, and the development of rumen papillae. Furthermore, ruminal microbial structure and function resulted in ruminal epithelial cell proliferation and development pathways activation, collectively provide compelling evidence supporting the capacity of alfalfa hay to enhance rumen development and health through ruminal micrbiota-host crosstalks. Our findings elucidate the functional response of the rumen to alfalfa hay introduction, providing new insights into strategies for promoting healthy development of the rumen in young ruminants.

Exploring the Impact of Ampelopsis Grossedentata Flavonoids on Growth Performance, Ruminal Microbiota, and Plasma Physiology and Biochemistry of Kids

This study was conducted to evaluate the influences of supplementing Ampelopsis grossedentata flavonoids (AGF) on the rumen bacterial microbiome, plasma physiology and biochemistry, and growth performance of goats. Twenty-four Nubian kids were randomly allocated to three dietary treatments: the control (CON, basal diet), the 1.0 g/kg AGF treatment (AGF), and the 12.5 mg/kg monensin treatment (MN). This trial consisted of 10 days for adaptation and 90 days for data and sample collection. The results reveal that Bacteroidetes, Firmicutes, and Proteobacteria are the dominant phyla in kids' rumen. Compared with the CON group, the alpha diversity in the MN and AGF groups significantly increased (p < 0.01). Beta-diversity shows that rumen microbial composition is more similar in the MN and AGF groups. LEfSe analysis shows that Prevotella_1 in the AGF group were significantly higher than those in the MN and CON group. The high-density lipoprotein cholesterol and glucose levels in the AGF group were significantly higher than those in the CON group (p < 0.05), whereas the low-density lipoprotein cholesterol, glutamic-pyruvic transaminase, and alkaline phosphatase levels exhibited the opposite trend. The average daily gains in the AGF and MN groups significantly increased, while the feed-to-gain ratios were significantly decreased (p < 0.05). The results suggest that adding AGF to the diet improves microbial composition and has important implications for studying juvenile livestock growth and improving economic benefits.

Exploring the growing forest musk deer (Moschus berezovskii) dietary protein requirement based on gut microbiome

It is necessary to assess the appropriate dietary protein level of the forest musk deer (FMD), as nutritional needs are unclear. The microbiome in gastrointestinal tracts plays an important role in regulating nutrient utilization, absorption and host growth or development. Thus, we aimed to evaluate growth performance, nutrient digestibility and fecal microbiome of growing FMD supplied with different protein levels of diets. Eighteen 6-month-old male FMD with an initial weight 5.0 ± 0.2 kg were used in a 62-day trial. The animals were randomly distributed to three groups, the dietary crude protein (CP) level was 11.51% (L), 13.37% (M), and 15.48% (H). The results showed that the CP digestibility decreased as dietary CP level increased (p &lt; 0.01). Compared with group L and H, FMD in M group has higher average daily gain, feed efficiency and neutral detergent fiber digestibility. For the fecal bacterial community, the percentage of Firmicutes was increased, Bacteroidetes was decreased and the diversity of microbiota significantly reduced (p &lt; 0.05) with the increasing of dietary protein. The proportion of Ruminococcaceae_005, Ruminococcaceae_UCG-014 and uncultured_bacterium_f_Lachnospiraceae were significantly increased wtih rising CP, the proportions of Bacteroides and Rikenellaceae_RC9_gut_group were significantly decrease nevertheless at the genus level. The higher abundance of f_Prevotellaceae and g_Prevotellaceae_UCG_004 were found at M group by LEfSe analysis. The relative abundance of uncultured_bacterium_f_Ruminococcaceae was positively correlated with the average daily gain and feed conversion ratio (p &lt; 0.05), whereas Family_XIII_AD3011_group was negatively correlated with feed conversion ratio (p &lt; 0.05). The UPGMA tree showed L and M groups were closer in clustering relationship, while H group was clustered separately into a branch, which indicated that the bacterial structure had changed greatly with protein level increased from 13.37 to 15.48%. Overall, our results indicated that the optimum dietary CP for the growing FMD was 13.37%.

Metagenome reveals caprine abomasal microbiota diversity at early and late stages of Haemonchus contortus infection

Haemonchus contortus is one of the most detrimental gastrointestinal nematode parasites for small ruminants, especially in tropics and subtropics. Gastrointestinal nematode and microbiota share the same microhabitat; thus they interact with each other and their host. Metagenomics tools provide a promising way to examine the alterations in the gastric microbial composition induces by gastrointestinal parasites. In this study, we used metagenomics tools to characterize the impact of H. contortus infection on the caprine abomasal microbiota at early and late stage of infection and compared it with non-infected control. Our results showed that H. contortus infection caused a significant increase in abomasal pH at early (7 days post-infection) and late stage of infection (56 days post-infection). The analysis of alpha and beta diversity showed that the microbiota diversity both in number and in proportion was significantly affected at early and late stage of infection. All microbiota classes are impacted by H. contortus infection but Clostridia and Bacteroidia are more concerned. In infected animals, the genera Prevotella decreased at 7 and 56 days post-infection. Here we showed that the abomasal microbiota was significantly affected early after H. contortus infection, and these changes persist at late stage of the infection.

Litter size influences rumen microbiota and fermentation efficiency, thus determining host early growth in goats

Introduction

Multiple litters are accompanied by low birth weight, low survival rates, and growth rates in goats during early life. Regulating rumen microbiota structure can indirectly or directly affect host metabolism and animal growth. However, the relationship between high litter size and rumen microbiome, rumen fermentation, and growth performance in goat kids is unclear.

Methods

In the present study, thirty 6-month-old, female goats were investigated, of which 10 goats were randomly chosen from single, twin and triplet goats respectively, and their birth weight was recorded. From birth, all goats were subjected to the same feed and management practices. Individual weaning and youth body weight were measured, and the rumen fluid samples were collected to characterize the bacterial communities and to determine the ruminal volatile fatty acids (VFA), free amino acids (AA), and free fatty acids (FA) concentration of those young goats.

Results and Discussion

Compared with the single and twin goats, triplet goats have lower weaning and youth body weight and average daily gain (ADG). Ruminal propionate, butyrate, and total VFA were decreased in triplet goats. Meanwhile, ruminal AA, such as branched chain amino acids (BCAA), essential amino acids (EAA), unsaturated fatty acids (UFA), and monounsaturated fatty acids (MUFA) were decreased, while saturated fatty acids (SFA) and odd and branched chain fatty acids (OBCFA) were increased in triplet goats. Our results also revealed that litter size significantly affected the rumen bacterial communities, and triplet goats had a lower the Firmicutes: Bacteroidota ratio, the abundance of Firmicutes phylum, Rikenellaceae family, and Rikenellaceae RC9 gut group, and had a higher proportion of Prevotellaceae family, and several genera of Prevotellaceae, such as Prevotella, and unclassified f Prevotellaceae. Furthermore, Spearman's correlation network analysis showed that the changes in the rumen bacteria were associated with changes in rumen metabolites. In conclusion, this study revealed that high litter size could bring disturbances to the microbial communities and decrease the rumen fermentation efficiency and growth performance, which can be utilized to better understand variation in microbial ecology that will improve growth performance in triplet goats.

The ratios of dietary non-fibrous carbohydrate (NFC) to neutral detergent fiber (NDF) influence intestinal immunity of rabbits by regulating gut microbiota composition and metabolites

Carbohydrate is the most common macronutrient consumed across all phases of the diet and acts as a potential regulator in modulating the gut microbiota in animals. However, the influences of dietary non-fibrous carbohydrate (NFC) to neutral detergent fiber (NDF) in different ratios on gut microbiota, metabolites, intestinal immunity, and growth performance have not been fully explored. A total of 135 healthy weaned rabbits (45.1 ± 0.7 d of age) with an average body weight of 1.08 ± 0.07 kg were randomly divided into five groups. Under the same other nutrient levels, rabbits were fed diets with NFC/NDF ratios of 0.7 (T1), 1.0 (T2), 1.3 (T3), 1.6 (T4), and 1.9 (T5). During the 28-day experiment, T3 rabbits showed the highest final body weight and the lowest feed-to-weight ratio than T5 rabbits (P < 0.05) but no significant difference with T1 or T2 rabbits. The expression of cecal pro-inflammatory factors IL-1β and TNF-α was increased in the T4 and T5 than in those of other groups (P < 0.05). Conversely, the tight junction proteins (ZO-1, Claudin-1, and Occludin) were decreased to varying degrees in the T4 and T5 groups. The pH value in the cecal digesta of T5 rabbits was lower than that of T1, T2, and T3 (P < 0.05), while the concentration of volatile fatty acids and propionate was higher than those of T1, T2, and T3 rabbits (P < 0.05). In terms of gut microbiota, at the phylum level, the relative burden of Firmicutes and Actinobacteria in T2 rabbits was the highest (P < 0.05), and the relative burden of Proteobacteria in T5 rabbits was higher than that of other groups (P < 0.05). At the genus level, the relative burden of Ruminococcus was higher in T2 and T3 rabbits than that of other groups, and T5 rabbits have the lowest relative burden of Ruminococcus. Combination analysis showed that cecal metabolites were positively associated with fermentation-related phenotypes and the burden of Firmicutes (P < 0.05). In conclusion, different dietary NFC/NDF ratios can affect the intestinal immune response and growth performance of rabbits, and there was a positive effect when dietary NFC/NDF = 1.0-1.3.

Tannic acid reduced apparent protein digestibility and induced oxidative stress and inflammatory response without altering growth performance and ruminal microbiota diversity of Xiangdong black goats

The present study was performed to evaluate the impacts of tannic acid (TA) supplementation at different levels on the growth performance, physiological, oxidative and immunological metrics, and ruminal microflora of Xiangdong black goats. Twenty-four goats were randomly assigned to four dietary treatments: the control (CON, basal diet), the low-dose TA group [TAL, 0.3 % of dry matter (DM)], the mid-dose TA group (TAM, 0.6 % of DM), and the high-dose TA group (TAH, 0.9 % of DM). Results showed that the growth performance was unaffected (P > 0.05) by adding TA, whilst the 0.3 % and 0.6 % TA supplementation significantly decreased (P < 0.05) the apparent digestibility of crude protein (CP) and ruminal NH3-N concentration, and raised (P < 0.05) the level of total volatile fatty acid (TVFA) in rumen. The increments of alanine aminotransferase (ALT), triglyceride (TG), cortisol (CORT), total antioxidant capacity (T-AOC), interleukin (IL)-1β, IL-6, and serumamyloid A (SAA), and decrements of globulin (GLB), immunoglobulin G (IgG), cholinesterase (CHE), glutathione reductase (GR), creatinine (CRE), growth hormone (GH), high-density lipoprotein cholesterol (HDLC), and insulin-like growth factor 1 (IGF-1) to different extents by TA addition were observed. Although the Alpha and Beta diversity of rumen bacterial community remained unchanged by supplementing TA, the relative abundance of the predominant genus Prevotella_1 was significantly enriched (P < 0.05) in TAL. It could hence be concluded that the TA supplementation in the present trial generally decreased CP digestion and caused oxidative stress and inflammatory response without influencing growth performance and ruminal microbiota diversity. More research is needed to explore the premium dosage and mechanisms of effects for TA addition in the diet of goats.

Comparison of rumen bacterial communities between yaks (Bos grunniens) and Qaidam cattle (Bos taurus) fed a low protein diet with different energy levels

The yak (Bos grunniens), an indigenous bovine on the Qinghai-Tibetan plateau (QTP), is reported to digest low quality forage to a greater extent and to require less protein and energy for maintenance than the introduced Qaidam cattle (Bos taurus). Ruminal bacteria play a major role in feed degradation, and therefore, we hypothesized that ruminal bacteria composition would differ between yaks and cattle, and confer an advantage to yaks for poor quality diets. To test our hypothesis, we determined the ruminal bacteria profiles, rumen fermentation parameters, and enzyme activities in these bovine species consuming a low-protein diet differing in energy level. Six castrated yaks (155 ± 5.8 kg) and 6 castrated Qaidam cattle (154 ± 8.0 kg) were used in two concurrent 4 × 4 Latin square designs with 2 additional animals of each species in each period. The animals were offered a low-protein diet of 70.4 g/kg dry matter (DM) and one of four metabolizable energy levels, namely 6.62, 8.02, 9.42, and 10.80 MJ/kg. Ruminal pH, concentrations of ammonia-N and total volatile fatty acids (VFAs), the molar proportion of acetate, and the ratio of acetate to propionate (A:P) were greater (P < 0.05), whereas the molar proportion of propionate was lesser (P = 0.043) in yaks than in cattle. With increasing dietary energy level, ruminal pH, the molar proportion of acetate and the ratio of A:P decreased linearly (P < 0.05), whereas, the concentration of total VFAs, molar proportions of propionate, butyrate, iso-butyrate, and iso-valerate and concentration of ammonia-N increased linearly (P < 0.05). The relative abundance (RA) of Firmicutes increased linearly (P < 0.01), whereas, the RA of Bacteroidetes decreased linearly (P < 0.001) with increasing energy level in both bovine species. The RAs of Prevotella and Rikenellaceae_RC9_gut_group decreased linearly (P < 0.05) with increasing energy level in both yaks and cattle. The RAs of fibrolytic (e.g., Rikenellaceae_RC9_gut_group), and H₂-incorporating (e.g., Quinella) bacteria were greater (P < 0.05) in yaks than in cattle. We concluded that the two bovines differ in ruminal bacterial profiles and rumen fermentation parameters, and confer an advantage to yaks over cattle in consuming a low protein diet with differing energy level.

Effect of dietary peNDF levels on digestibility and rumen fermentation, and microbial community in growing goats

Physically effective neutral detergent fiber (peNDF) is a concept that accounts for the particle length of NDF in diets, sustaining the normal chewing behavior and rumen fermentation of ruminants. Specifically, peNDF>1.18 is the commonest one that is calculated from NDF and the percentage of feed dry matter left on the 1.18, 8.00, and 19.00 mm sieves. This study aimed to investigate the effects of different levels of peNDF>1.18 on the rumen microbiome and its correlation with nutrient digestibility and rumen fermentation in goats. A total of 30 Lezhi black goats were randomized and blocked to five dietary treatments (n = 6). All the diets were identical in composition but varied in hay lengths, leading to the different peNDF>1.18 content of the diets: 32.97, 29.93, 28.14, 26.48, and 24.75%. The results revealed that the nutrient digestibility increased when dietary peNDF>1.18 levels decreased from 32.97% to 28.14%, with the highest digestibility at 28.14% peNDF>1.18 treatment, after which nutrient digestibility decreased with the decreasing of dietary peNDF levels. Ruminal NH3-N concentrations in the 29.93% and 28.14% groups were higher than that in the 24.75% group (p < 0.05). Ruminal microbial protein concentration was the highest in the 32.97% group (p < 0.05). Daily CH4 production in the 32.97% and 24.75% peNDF>1.18 treatments was lower than that in the 26.48% group (p < 0.05) and no differences were observed among other groups. The relative abundance of rumen fungi at the phylum and genus levels and archaea at the species were affected by dietary peNDF>1.18 content. In conclusion, decreasing dietary peNDF>1.18 levels within a certain range can improve nutrient digestibility and change the rumen microbial community structure of goats. Dietary peNDF>1.18 level should be 28.14% (roughage length around 1 cm) among the five levels for 4 months Lezhi black goats with the purpose of optimal nutrient digestibility.