Supplementation With Phytogenic Compounds Modulates Salivation and Salivary Physico-Chemical Composition in Cattle Fed a High-Concentrate Diet

Feeding live yeast (Saccharomyces cerevisiae) improved performance of mid-lactation dairy cows by altering ruminal bacterial communities and functions of serum antioxidation and immune responses

BACKGROUND

The utilization of live yeast (Saccharomyces cerevisiae, YE) in dairy cows is gaining traction in dairy production as a potential strategy to improve feed efficiency and milk yield. However, the effects of YE on dairy cow performance remain inconsistent across studies, leaving the underlying mechanisms unclear. Hence, the primary aim of this study was to investigate the impact of YE supplementation on lactation performance, ruminal microbiota composition and fermentation patterns, as well as serum antioxidant capacity and immune functions in dairy cows.

RESULTS

Supplementation with YE (20 g/d/head) resulted in enhancements in dairy cow's dry matter intake (DMI) (P = 0.016), as well as increased yields of milk (P = 0.002) and its components, including solids (P = 0.003), fat (P = 0.014), protein (P = 0.002), and lactose (P = 0.001) yields. The addition of YE led to significant increases in the concentrations of ammonia nitrogen (NH3-N) (P = 0.023), acetate (P = 0.005), propionate (P = 0.025), valerate (P = 0.003), and total volatile fatty acids (VFAs) (P < 0.001) in rumen fermentation parameters. The analysis of 16s rRNA gene sequencing data revealed that the administration of YE resulted in a rise in the relative abundances of three primary genera including Ruminococcus_2 (P = 0.010), Rikenellaceae_RC9_gut_group (P = 0.009), and Ruminococcaceae_NK4A214_group (P = 0.054) at the genus level. Furthermore, this increase was accompanied with an enriched pathway related to amino acid metabolism. Additionally, enhanced serum antioxidative (P < 0.05) and immune functionalities (P < 0.05) were also observed in the YE group.

CONCLUSIONS

In addition to improving milk performance, YE supplementation also induced changes in ruminal bacterial community composition and fermentation, while enhancing serum antioxidative and immunological responses during the mid-lactation stage. These findings suggest that YE may exert beneficial effects on both rumen and blood metabolism in mid-lactation dairy cows.

Environmental impact of phytobiotic additives on greenhouse gas emission reduction, rumen fermentation manipulation, and performance in ruminants: an updated review

Ruminal fermentation is a natural process involving beneficial microorganisms that contribute to the production of valuable products and efficient nutrient conversion. However, it also leads to the emission of greenhouse gases, which have detrimental effects on the environment and animal productivity. Phytobiotic additives have emerged as a potential solution to these challenges, offering benefits in terms of rumen fermentation modulation, pollution reduction, and improved animal health and performance. This updated review aims to provide a comprehensive understanding of the specific benefits of phytobiotic additives in ruminant nutrition by summarizing existing studies. Phytobiotic additives, rich in secondary metabolites such as tannins, saponins, alkaloids, and essential oils, have demonstrated biological properties that positively influence rumen fermentation and enhance animal health and productivity. These additives contribute to environmental protection by effectively reducing nitrogen excretion and methane emissions from ruminants. Furthermore, they inhibit microbial respiration and nitrification in soil, thereby minimizing nitrous oxide emissions. In addition to their environmental impact, phytobiotic additives improve rumen manipulation, leading to increased ruminant productivity and improved quality of animal products. Their multifaceted properties, including anthelmintic, antioxidant, antimicrobial, and immunomodulatory effects, further contribute to the health and well-being of both animals and humans. The potential synergistic effects of combining phytobiotic additives with probiotics are also explored, highlighting the need for further research in this area. In conclusion, phytobiotic additives show great promise as sustainable and effective solutions for improving ruminant nutrition and addressing environmental challenges.

Review: Mechanism, effectiveness, and the prospects of medicinal plants and their bioactive compounds in lowering ruminants' enteric methane emission

Animal nutritionists continue to investigate new strategies to combat the challenge of methane emissions from ruminants. Medicinal plants (MPs) are known to be beneficial to animal health and exert functional roles in livestock due to their phytogenic compounds with antimicrobial, immunostimulatory, antioxidative, and anti-inflammatory activities. Some MP has been reported to be anti-methanogenic and can effectively lower ruminants' enteric methane emissions. This review overviews trends in MP utilization in ruminants, their bioactivity and their effectiveness in lowering enteric methane production. It highlights the MP regulatory mechanism and the gaps that must be critically addressed to improve its efficacy. MP could reduce enteric methane production by up to 8-50% by regulating the rumen fermentation pathway, directing hydrogen toward propionogenesis, and modifying rumen diversity, structure, and population of the methanogens and protozoa. Yet, factors such as palatability, extraction techniques, and economic implications must be further considered to exploit their potential fully.

Postnatal development of salivary phosphate, sodium and potassium secretion in calves

The transition of young lambs and calves from a non-ruminating to a ruminating animal include substantial, developmental changes to alter saliva production. Due to the simultaneous development of the forestomach system, the salivary glands must transfer more and more substances such as bicarbonate and phosphate (Pi), but also sodium (Na), into saliva in order to create and to maintain optimal environmental conditions for microbial metabolism. The objective of the present study was to characterize the effects of different dietary energy levels on the ability of the salivary glands to concentrate minerals in young ruminants in more detail during the first 7 weeks of life. Blood and saliva samples were collected from twelve female calves of the German Holstein breed fed different levels of milk replacer. Plasma and saliva samples were collected over 7 weeks postpartum and Na, Pi and potassium (K) concentrations were measured. Salivary Na and Pi concentrations (p < 0.001) increased as a function of time and were not affected by varying energy intake, while K concentration (p < 0.001) decreased over the developmental period and was also not affected by energy intake. This suggests that the ability to specifically concentrate minerals such as Na and Pi in saliva follows a genetic program in the salivary glands rather than being influenced by dietary factors such as energy intake in young ruminants.

Prosthodontic implications of saliva and salivary gland dysfunction

PURPOSE

To provide a detailed overview of the fundamentals of saliva constituents and production. The review outlines the clinical manifestations as a consequence of salivary gland dysfunction and management strategies for patients with salivary gland dysfunction. Prosthodontic implications of saliva and salivary gland dysfunction are presented.

MATERIALS AND METHODS

English-language literature relating to saliva constituents, physiologic saliva production, clinical manifestations secondary to salivary gland dysfunction, salivary biomarkers, and management strategies were retrieved via electronic search. Relevant articles were summarized for this manuscript with a view toward providing pragmatic information.

RESULTS

Saliva is produced by three pairs of major and minor salivary glands. The major salivary glands, namely, the parotid, submandibular, and sublingual glands, contribute approximately 90% of saliva production. Saliva contains serous and mucinous secretions produced by different types of cells within salivary glands. Parasympathetic and sympathetic fibers innervate the major salivary glands, and upon stimulation, the parasympathetic innervation increases serous secretions, while the sympathetic innervation increases protein secretion. Stimulated saliva is mainly derived from the parotid glands which are composed of serous acini, while unstimulated saliva is mainly derived from the submandibular glands which are composed of mixed seromucous acini. As major salivary glands contribute the most to salivary flow, local or systemic factors influencing those glands can disrupt saliva production resulting in clinically significant oral manifestations.

CONCLUSION

This review provides a fundamental overview of saliva production. In addition, the review highlights the various clinical manifestations secondary to salivary gland dysfunction, explores salivary biomarkers for screening of systemic diseases, discusses management strategies for patients with salivary gland dysfunction, and outlines the prosthodontic implications of saliva and salivary gland dysfunction.

Comparative nutritional evaluation of the leaves of selected plants from the Poaceae family (bamboos and grasses) for sustainable livestock production in Ghana

Background

Sustainable animal feeding is essential for reducing poverty among Ghanaian smallholder livestock farmers. However, seasonality has a severe impact on the availability and quality of conventional animal feedstuffs, necessitating alternate feed sources.

Objective

This study evaluated and compared the nutritional characteristics of the leaves of three bamboo species namely; Bambusa balcooa (Beema), Oxytenanthera abyssinica (A. Rich.) Munro and Bambusa vulgaris; and three conventional types of grass, namely; Cenchrus purpureus, Megathyrsus maximus, and Brachiaria decumbens.

Materials and methods

The plant biomasses were subjected to the standard analytical procedures of proximate and detergent fiber systems to highlight their dry matter (DM), crude protein (CP), crude fiber (CF), ether extract (EE), ash, nitrogen-free extract (NFE), neutral detergent fiber (NDF), acid detergent fiber (ADF), and acid detergent lignin (ADL). Other nutritional characteristics were estimated using the chemical compositions.

Statistical analysis

Data was analyzed using Generalized Linear Model procedures in Minitab Statistical Software at a 5% significant level.

Results

Results showed a significantly (P &lt; 0.05) higher DM (~918 g/kgDM), CP (~153 g/kgDM), and EE (~153 g/kgDM) in B. vulgaris leaves. O. abyssinica leaves had the maximum ash (~139 g/kgDM) while those of M. maximus had the highest carbohydrate (~709 g/kgDM) and CF (~492 g/kgDM). Compared to the grasses, the bamboo had a higher pool of DM (~910 vs. 836 g/kgDM), CP (~133 vs. 75 g/kgDM), EE (~137 vs. 82 g/kgDM), ash (~134 vs. 89 g/kgDM), hemicellulose (~79 vs. 28 g/kgDM), dry matter intake (~25 vs. 24%), digestible dry matter (~58 vs. 53%), and relative feed value (~111 vs. 105). In contrast, the grasses had higher mean ADF (~461 vs. 402 g/kgDM), cellulose (~417 vs. 397 g/kgDM), and ADL (~5 vs. 0.4 g/kgDM).

Conclusion

The study suggests that bamboo leaves could have high nutritional characteristics to supplement or even replace conventional grasses and other crop residues in the diets of ruminants, especially during the dry season.

Diet and phytogenic supplementation substantially modulate the salivary proteome in dairy cows

Phytogenic compounds may influence salivation or salivary properties. However, their effects on the bovine salivary proteome have not been evaluated. We investigated changes in the bovine salivary proteome due to transition from forage to high-concentrate diet, with and without supplementation with a phytogenic feed additive. Eight non-lactating cows were fed forage, then transitioned to a 65% concentrate diet (DM basis) over a week. Cows were control (n = 4, CON) or supplemented with a phytogenic feed additive (n = 4, PHY). Proteomic analysis was conducted using liquid chromatography coupled with mass spectrometry. We identified 1233 proteins; 878 were bovine proteins, 189 corresponded to bacteria, and 166 were plant proteins. Between forage and high-concentrate, 139 proteins were differentially abundant (P < 0.05), with 48 proteins having a log2FC difference > |2|. The salivary proteome reflected shifts in processes involving nutrient utilization, body tissue accretion, and immune response. Between PHY and CON, 195 proteins were differently abundant (P < 0.05), with 37 having a log2FC difference > |2|; 86 proteins were increased by PHY, including proteins involved in smell recognition. Many differentially abundant proteins correlated (r > |0.70|) with salivary bicarbonate, total mucins or pH. Results provide novel insights into the bovine salivary proteome using a non-invasive approach, and the association of specific proteins with major salivary properties influencing rumen homeostasis. SIGNIFICANCE: Phytogenic compounds may stimulate salivation due to their olfactory properties, but their effects on the salivary proteome have not been investigated. We investigated the effect of high-concentrate diets and supplementation with a phytogenic additive on the salivary proteome of cows. We show that analysis of cows' saliva can be a non-invasive approach to detect effects occurring not only in the gut, but also systemically including indications for gut health and immune response. Thus, results provide unique insights into the bovine salivary proteome, and will have a crucial contribution to further understand animal response in terms of nutrient utilization and immune activity due to the change from forage to a high-energy diet. Additionally, our findings reveal changes due to supplementation with a phytogenic feed additive with regard to health and olfactory stimulation. Furthermore, findings suggest an association between salivary proteins and other components like bicarbonate content.

Differentially CTCF-Binding Sites in Cattle Rumen Tissue during Weaning

The weaning transition in calves is characterized by major structural changes such as an increase in the rumen capacity and surface area due to diet changes. Studies evaluating rumen development in calves are vital to identify genetic mechanisms affected by weaning. This study aimed to provide a genome-wide characterization of CTCF-binding sites and differentially CTCF-binding sites (DCBS) in rumen tissue during the weaning transition of four Holstein calves to uncover regulatory elements in rumen epithelial tissue using ChIP-seq. Our study generated 67,280 CTCF peaks for the before weaning (BW) and 39,891 for after weaning (AW). Then, 7401 DCBS were identified for the AW vs. BW comparison representing 0.15% of the cattle genome, comprising ~54% of induced DCBS and ~46% of repressed DCBS. Most of the induced and repressed DCBS were in distal intergenic regions, showing a potential role as insulators. Gene ontology enrichment revealed many shared GO terms for the induced and the repressed DCBS, mainly related to cellular migration, proliferation, growth, differentiation, cellular adhesion, digestive tract morphogenesis, and response to TGFβ. In addition, shared KEGG pathways were obtained for adherens junction and focal adhesion. Interestingly, other relevant KEGG pathways were observed for the induced DCBS like gastric acid secretion, salivary secretion, bacterial invasion of epithelial cells, apelin signaling, and mucin-type O-glycan biosynthesis. IPA analysis further revealed pathways with potential roles in rumen development during weaning, including TGFβ, Integrin-linked kinase, and Integrin signaling. When DCBS were further integrated with RNA-seq data, 36 putative target genes were identified for the repressed DCBS, including KRT84, COL9A2, MATN3, TSPAN1, and AJM1. This study successfully identified DCBS in cattle rumen tissue after weaning on a genome-wide scale and revealed several candidate target genes that may have a role in rumen development, such as TGFβ, integrins, keratins, and SMADs. The information generated in this preliminary study provides new insights into bovine genome regulation and chromatin landscape.

Effect of Duration of High-Grain Feeding on Chewing, Feeding Behavior, and Salivary Composition in Cows with or without a Phytogenic Feed Supplement

Switching diets from forage to a high-grain (HG) diet increases the risk of rumen fermentation disorders in cattle. However, the effects of the duration of the HG feeding, after the diet switch, on animal behavior and health have received considerably less attention. This experiment primarily aimed to assess the effects of the duration of an HG diet on the chewing, eating, and lying behavior and salivation dynamics in a control group (CON) and a group of cows receiving a phytogenic feed supplement (TRT) at 0.04% (DM basis), which included L-menthol, thymol, eugenol, mint oil, and cloves powder. The experiment was a crossover design with nine non-lactating cows, and two experimental periods with an intermediate washout of four weeks. In each period, the cows were first fed a forage diet for a week to collect baseline measurements representing week 0; then, the diet was switched over a week to HG (65% concentrate), which was fed for four continuous weeks (week 1, week 2, week 3, and week 4 on an HG diet, respectively). The cows were divided in two groups of four and five animals and were randomly allocated to CON or TRT. The data analysis revealed that at the start of the HG feeding, the dry matter intake and the cows’ number of lying bouts increased, but the eating time, rumination time, and meal frequency decreased, resulting in a greater eating rate. We also found that an advanced duration on an HG diet further decreased the rumination time, total chewing time, chewing index, and sorting in favor of short feed particles, with the lowest values in week 4. The feed bolus size increased but feed the ensalivation decreased in week 4 compared to week 0. The dietary switch increased salivary lysozyme activity, and the advanced duration on the HG diet increased salivary pH, but salivary phosphate decreased in weeks 1 and 2 on the HG diet. Supplementation with TRT increased sorting in favor of physically effective NDF (peNDF) in week 2 and increased salivary pH in week 4 on an HG diet. Overall, the negative effects of the HG diet in cattle are more pronounced during the initial stage of the HG feeding. However, several detrimental effects were exacerbated with the cows’ advanced duration on feed, with host adaptive changes still observed after 3 and 4 weeks following the diet switch. The TRT mitigated some of the negative effects through the temporal improvement of the salivary properties and the intake of peNDF, which are known to modulate rumen fermentation.

Supplementing a Phytogenic Feed Additive Modulates the Risk of Subacute Rumen Acidosis, Rumen Fermentation and Systemic Inflammation in Cattle Fed Acidogenic Diets

Feeding with high-concentrate diets increases the risk of subacute ruminal acidosis (SARA). This experiment was conducted to evaluate whether supplementing a phytogenic feed additive based on L-menthol, thymol, eugenol, mint oil (Mentha arvensis) and cloves powder (Syzygium aromaticum) (PHY) can amend the ruminal fermentation profile, modulate the risk of SARA and reduce inflammation in cattle. The experiment was designed as a crossover design with nine non-lactating Holstein cows, and was conducted in two experimental runs. In each run, cows were fed a 100% forage diet one week (wk 0), and were then transitioned stepwise over one week (0 to 65% concentrate, wk adapt.) to a high concentrate diet that was fed for 4 weeks. Animals were fed diets either with PHY or without (CON). The PHY group had an increased ruminal pH compared to CON, reduced time to pH < 5.8 in wk 3, which tended to decrease further in wk 4, reduced the ruminal concentration of D-lactate, and tended to decrease total lactate (wk 3). In wk 2, PHY increased acetate, butyrate, isobutyrate, isovalerate, and the acetate to propionate ratio compared to CON. Phytogenic supplementation reduced inflammation compared to CON in wk 3. Overall, PHY had beneficial effects on ruminal fermentation, reduced inflammation, and modulated the risk of SARA starting from wk 3 of supplementation.

Characterization of Microbial Intolerances and Ruminal Dysbiosis Towards Different Dietary Carbohydrate Sources Using an in vitro Model

AIM

This study aimed to characterize the critical points for determining the development of dysbiosis associated with feed intolerances and ruminal acidosis.

METHODS AND RESULTS

A metabologenomics approach was used to characterize dynamic microbial and metabolomics shifts using the rumen simulation technique (RUSITEC) by feeding native cornstarch (ST), chemically-modified cornstarch (CMS), or sucrose (SU). SU and CMS elicited the most drastic changes as rapidly as 4 h after feeding. This was accompanied by a swift accumulation of D-lactate, and the decline of benzoic and malonic acid. A consistent increase in Bifidobacterium and Lactobacillus as well as a decrease in fibrolytic bacteria was observed for both CMS and ST after 24 h, indicating intolerances within the fiber degrading populations. However, an increase in Lactobacillus was already evident in SU after 8 h. An inverse relationship between Fibrobacter and Bifidobacterium was observed in ST. In fact, Fibrobacter was positively correlated with several short-chain fatty acids (SCFA), while Lactobacillus was positively correlated with lactic acid, hexoses, hexose-phosphates, pentose phosphate pathway (PENTOSE-P-PWY) and heterolactic fermentation (P122-PWY).

CONCLUSIONS

The feeding of sucrose and modified starches, followed by native cornstarch, had a strong disruptive effect in the ruminal microbial community. Feed intolerances were shown to develop at different rates based on the availability of glucose for ruminal microorganisms.

SIGNIFICANCE OF THE STUDY

These results can be used to establish patterns of early dysbiosis (biomarkers) and develop strategies for preventing undesirable shifts in the ruminal microbial ecosystem.