Effects of dietary menthol-rich bioactive lipid compounds on zootechnical traits, blood variables and gastrointestinal function in growing sheep

Effects of different combinations of antibacterial compound supplements in calf pellets on growth performance, health, blood parameters, and rumen microbiome of dairy calves

This study investigated the effects of different combinations of antibacterial compounds (attapulgite, plant essential oils, and chitosan oligosaccharides) on growth performance, blood biochemical parameters, and rumen microbiome of calves. A total of 48 preweaning calves were randomly divided into four groups (n = 12 per group), and fed the following full mixed-ration granule diets for the 67-d-feeding trial: (1) basal diet (control group); (2) basal diet +1,000 g/t attapulgite, plant essential oils, and chitosan oligosaccharide (AEOCO group); (3) basal diet +1,000 g/t attapulgite and chitosan oligosaccharide (ACO group); and (4) basal diet +1,000 g/t attapulgite and plant essential oil (AEO group). The results showed that the daily weight gain of the AEOCO and AEO groups significantly increased (p < 0.05), whereas the feed conversion ratio decreased compared with that of the control group. Among the three treatment groups, AEO group showed the most positive effect, with the diarrhea rate reduced by 68.2% compared with that of the control group. Total protein and globulin levels were lower in the AEO group than in the control group. Albumin levels were higher in the AEOCO and AEO groups than in the control group. Immunoglobulin A, immunoglobulin G, and immunoglobulin M concentrations were higher in the AEOCO group (p < 0.05) than in the control group. The interleukin-6 concentration was lower in the AEOCO and AEO groups than in the control group (p < 0.05). The Chao 1 richness and ACE indices were higher in the AEOCO group than in the control group (p < 0.05). The ACO group had a significantly lower (p < 0.05) relative abundance of Firmicutes than the control group. The relative abundance of Bacteroidetes was the lowest in the control group, whereas that of Spirochaetota and Fibrobacteriota was the highest (p < 0.05). The relative abundance of Succiniclasticum was higher in the ACO and AEO groups (p < 0.05). These findings indicate that the combination of attapulgite, plant essential oils, and chitosan oligosaccharides has ameliorative effects on the growth performance, blood parameters, and rumen microbiome of calves.

Peppermint and menthol: a review on their biochemistry, pharmacological activities, clinical applications, and safety considerations

In this manuscript, we conducted a comprehensive review of the diverse effects of peppermint on human health and explored the potential underlying mechanisms. Peppermint contains three main groups of phytochemical constituents, including essential oils (mainly menthol), flavonoids (such as hesperidin, eriodictyol, naringenin, quercetin, myricetin, and kaempferol), and nonflavonoid phenolcarboxylic acids. Peppermint exhibits antimicrobial, antioxidant, anti-inflammatory, immunomodulatory, anti-cancer, anti-aging, and analgesic properties and may be effective in treating various disorders, including gastrointestinal disorders (e.g., irritable bowel syndrome, dyspepsia, constipation, functional gastrointestinal disorders, nausea/vomiting, and gallbladder stones). In addition, peppermint has therapeutic benefits for psychological and cognitive health, dental health, urinary retention, skin and wound healing, as well as anti-depressant and anti-anxiety effects, and it may improve memory. However, peppermint has paradoxical effects on sleep quality and alertness, as it has been shown to improve sleep quality in patients with fatigue and anxiety, while also increasing alertness under conditions of monotonous work and relaxation. We also discuss its protective effects against toxic agents at recommended doses, as well as its safety and potential toxicity. Overall, this review provides the latest findings and insights into the properties and clinical effects of peppermint/menthol and highlights its potential as a natural therapeutic agent for various health conditions.

Review: Harmonised in vitro digestion and the Ussing chamber for investigating the effects of polyphenols on intestinal physiology in monogastrics and ruminants

Because of the relevant effects of plant-derived polyphenols (PPs) on monogastrics and ruminants' nutrition, emissions and performance, an increasing number of in vivo and in vitro studies are being performed to better understand the mechanisms of action of polyphenols at both the ruminal and intestinal levels. The biological properties of these phenolic compounds strongly depend on their degradation, absorption and metabolism. The harmonised in vitro digestion method (INFOGEST) is one of the most reliable in vitro methods used to assess the bioaccessibility and or antioxidant activity of PP contained in different matrixes, as well as the interactions of PP and their degradation products with other feed ingredients. The effects of PP released from their matrix after in vitro digestion on different intestinal physiological parameters, such as epithelium integrity, can be further evaluated by the use of ex vivo models such as the Ussing chamber. This review aims to describe the combination of the INFOGEST method, coupled with the Ussing chamber as a valuable model for the digestion and subsequent effects and absorption of phenolic compounds in monogastrics and potentially in ruminants. The advances, challenges and limits of this approach are also discussed.

Blood calcium concentration and performance in periparturient and early lactating dairy cows is influenced by plant bioactive lipid compounds

Previous studies ex vivo suggested that plant bioactive lipid compounds (PBLC) can increase ruminal calcium absorption. Therefore, we hypothesized that PBLC feeding around calving may potentially counteract hypocalcemia and support performance in postpartum dairy cows. The corresponding aim of the study was to investigate the effect of PBLC feeding on blood minerals in Brown Swiss (BS) and hypocalcemia-susceptible Holstein Friesian (HF) cows during the period from d -2 to 28 relative to calving and on milk performance until d 80 of lactation. A total of 29 BS cows and 41 HF cows were divided each into a control (CON) and PBLC treatment group. The latter was supplemented with 1.7 g/d menthol-rich PBLC from 8 d before expected calving to 80 d postpartum. Milk yield and composition, body condition score and blood minerals were measured. Feeding PBLC induced a significant breed × treatment interaction for iCa, supporting that PBLC increased iCa exclusively in HF cows; the increase was 0.03 mM over the whole period and 0.05 mM from d 1 to 3 after calving. Subclinical hypocalcemia was seen in one BS-CON and 8 HF-CON cows and 2 BS-PBLC and 4 HF-PBLC cows. Clinical milk fever was detected only in HF cows (2 HF-CON and one HF-PBLC). Other tested blood minerals, such as sodium, chloride, and potassium, as well as blood glucose, were neither affected by PBLC feeding nor breed, nor were their 2-way interactions, except for higher sodium levels in PBLC cows on d 21. Body condition score showed no effect of treatment, except for a lower body condition score in BS-PBLC compared with BS-CON at d 14. Dietary PBLC increased milk yield, milk fat yield, and milk protein yield at 2 consecutive dairy herd improvement test days. As indicated by treatment × day interactions, energy-corrected milk yield and milk lactose yield were increased by PBLC on the first test day only, and milk protein concentration decreased from test d 1 to test d 2 in CON only. The concentrations of fat, lactose, and urea, as well as somatic cell count, were not affected by treatment. The weekly milk yield over the first 11 wk of lactation was 29.5 kg/wk higher for PBLC versus CON across breeds. It is concluded that the applied PBLC induced a small but measurable improvement of calcium status in HF cows in the study period and had additional positive effects on milk performance in both breeds.

Essential Oils as a Dietary Additive for Small Ruminants: A Meta-Analysis on Performance, Rumen Parameters, Serum Metabolites, and Product Quality

There is an increasing pressure to identify natural feed additives that improve the productivity and health of livestock, without affecting the quality of derived products. The objective of this study was to evaluate the effects of dietary supplementation with essential oils (EOs) on productive performance, rumen parameters, serum metabolites, and quality of products (meat and milk) derived from small ruminants by means of a meta-analysis. Seventy-four peer-reviewed publications were included in the data set. Weighted mean differences (WMD) between the EOs treatments and the control treatment were used to assess the magnitude of effect. Dietary inclusion of EOs increased (p < 0.05) dry matter intake (WMD = 0.021 kg/d), dry matter digestibility (WMD = 14.11 g/kg of DM), daily weight gain (WMD = 0.008 kg/d), and feed conversion ratio (WMD = −0.111). The inclusion of EOs in small ruminants’ diets decreased (p < 0.05) ruminal ammonia nitrogen concentration (WMD = −0.310 mg/dL), total protozoa (WMD = −1.426 × 105/mL), methanogens (WMD = −0.60 × 107/mL), and enteric methane emissions (WMD = −3.93 L/d) and increased ruminal propionate concentration (WMD = 0.726 mol/100 mol, p < 0.001). The serum urea concentration was lower (WMD = −0.688 mg/dL; p = 0.009), but serum catalase (WMD = 0.204 ng/mL), superoxide dismutase (WMD = 0.037 ng/mL), and total antioxidant capacity (WMD = 0.749 U/mL) were higher (p < 0.05) in response to EOs supplementation. In meat, EOs supplementation decreased (p < 0.05) the cooking loss (WMD = −0.617 g/100 g), malondialdehyde content (WMD = −0.029 mg/kg of meat), yellowness (WMD = −0.316), and total viable bacterial count (WMD = −0.780 CFU/g of meat). There was higher (p < 0.05) milk production (WMD = 0.113 kg/d), feed efficiency (WMD = 0.039 kg/kg), protein (WMD = 0.059 g/100 g), and lactose content in the milk (WMD = 0.100 g/100 g), as well as lower somatic cell counts in milk (WMD = −0.910 × 103 cells/mL) in response to EOs supplementation. In conclusion, dietary supplementation with EOs improves productive performance as well as meat and milk quality of small ruminants. In addition, EOs improve antioxidant status in blood serum and rumen fermentation and decrease environmental impact.

Expression Profiles of the Ovine IL18 Gene and Association of Its Polymorphism With Hematologic Parameters in Hu Lambs

Hematological traits are important indexes to evaluate health status and immunological conditions in human and livestock. In this study, we measured the hematologic indexes of 819 male Hu lambs and performed the descriptive statistical analysis. The results showed the coefficients of variation of partial indexes were >10%, and the heritability for mean erythrocyte volume (MCV), white blood cell count (WBC), hemoglobin concentration (HGB), hematocrit (HCT), and red blood cell (RBC) distribution-standard deviation (RDW_SD) were medium to high, ranging from 0.17 to 0.43. In addition, Interleukin 18 (IL18), as an important regulator of both innate and acquired immune responses, was selected as candidate gene and subjected to the expression profile analysis, single nucleotide polymorphism (SNP) scanning and association analysis by using quantitative real-time PCR (qRT-PCR), PCR amplification, Sanger sequencing, and KASP genotyping. The results of qRT-PCR indicated that IL18 is predominantly expressed in lymph and lung compared with that in the other tested tissues. In addition, three novel polymorphisms (g. 24991544 A > G, g. 24991651 A > G, and g. 24991749 C > T) were identified in IL18, and the three SNPs were in a strong linkage state. Therefore, only a SNP was genotyped and performed association analysis in the enlarged experimental population, the result of association analysis demonstrated that the polymorphism g. 24991651 A > G was significantly associated with RBC, MCV, MCHC, and RDW_CV. These results will provide the reference values and the novel genetic markers of hematological parameters in sheep.

Effect of dietary phytobiotic mixture on growth performance, nutrient utilization, and immunity in weaned piglets

This study investigated the effects of dietary phytobiotic mixture on growth performance, blood profiles, immune response, and fecal microorganisms in weaned piglets. Twenty four weaned crossbred piglets were equally divided into four groups in a completely randomized design. The animals in 4 groups were fed a basal diet added with (1) no antibiotics and phytobiotics (CON), (2) bacitracin (0.5 g/kg; AB), (3) a blend of Cinnamomum zeylanicum and Trachyspermum copticum essential oils (0.3 g/kg and 0.4 g/kg, respectively; EO), and (4) plant extracts (PEO) of Mikania micrantha and Garcinia lanceifolia (2.8 g/kg and 1.4 g/kg, respectively) and C. zeylanicum and T. copticum essential oils (0.3 g/kg and 0.4 g/kg, respectively). Inclusion of AB, EO, and PEO did not affect final body weight, average daily gain, feed intake, feed efficiency, and nutrient digestibility. Compared with the CON, serum protein profiles were not affected, but a few lipid profiles were improved, particularly cholesterol, low-density lipoprotein, and high-density lipoprotein in the EO and PEO groups. Lymphocyte proliferation index and concentrations of IgG and IgA and TNF-α were not affected by any treatments. The concentrations of IgM increased (P = 0.04) at 28 days and tended to increase (P = 0.10) at 56 days in the EO group. Serum IL-1β levels decreased on days 28 and 56 in the EO and PEO groups. Fecal Lactobacilli population generally increased (P < 0.01) in the AB, EO, and PEO groups compared with the CON. Fecal enterobacterial numbers were always greater for AB than for CON, EO, or PEO, but enterobacterial populations were sometimes lower in the EO group than the CON group. In conclusion, dietary EO or PEO has no effect on the growth performance, but it may improve a few lipid profiles, immune responses, and fecal microbial populations in piglets.

Menthol stimulates calcium absorption in the rumen but not in the jejunum of sheep

Stimulation of Ca²⁺ absorption can counteract hypocalcemia at the onset of lactation. The plant bioactive lipid compound (PBLC) menthol is an agonist for nonselective cation channels of the transient receptor potential (TRP) family. It acutely stimulated Ca²⁺ absorption in ruminal epithelia of nonadapted animals ex vivo and caused higher plasma Ca²⁺ concentrations in cows and sheep in vivo. To elucidate the pathway by which menthol feeding increases plasma Ca²⁺ level, the present study aimed to investigate the long-term dose-dependent effects of dietary menthol-rich PBLC on Ca²⁺ absorption and mRNA abundances of TRP channels in both rumen and jejunum. Twenty-four growing Suffolk sheep were equally distributed to a Con, PBLC-L, and PBLC-H group, which received 0, 80, and 160 mg/d of a menthol-rich PBLC. After 4 wk, ruminal and jejunal epithelia were analyzed for mRNA abundances of TRPA1, TRPV3, TRPV5-6, and TRPM6-8 genes. The Ca²⁺ flux rates and electrophysiological properties of epithelia from rumen and mid-jejunum were measured in Ussing chambers in the presence and absence of mucosal Na⁺. Acute changes in Ca²⁺ flux rates were measured after mucosal application of 50 µM menthol. Ruminal epithelia had quantifiable transcripts of TRPV3 = TRPM6 >TRPM7 >TRPA1 with no difference among feeding groups. Jejunum had quantifiable transcripts of TRPM7 >TRPA1 ≥ TRPM6 ≥ TRPV6 >TRPV5, where TRPA1, TRPV5, and TRPV6 tended to decrease linearly with increasing PBLC dose. Absorptive net flux of Ca²⁺ was detected only in the rumen, whereas jejunum showed a high passive permeability to Ca²⁺. Net flux rates of Ca²⁺ in the rumen increased in a quadratic manner (highest in PBLC-L animals) and were systematically decreased with the omission of mucosal Na⁺. Short-circuit current increased in both PBLC feeding groups compared with Con only in the rumen. Acute application of menthol-stimulated mucosal-to-serosal and net Ca²⁺ flux rates only in ruminal epithelia with higher stimulation in PBLC-fed animals. We conclude that Ca²⁺ transport is mainly active and transcellular in the rumen. It most likely involves TRPV3 that can be stimulated by menthol. Pre-feeding of menthol-rich PBLC enhances ruminal Ca²⁺ absorption and sensitizes it to acute stimulation by menthol. By contrast, intestinal Ca²⁺ absorption is not sensitive to menthol stimulation. Menthol could be used as a tool to enhance ruminal Ca²⁺ absorption and to prevent hypocalcemia in dairy cows.

Influence of Plant Bioactive Compounds on Intestinal Epithelial Barrier in Poultry

Natural plant bioactive compounds (PBC) have recently been explored as feed additives to improve productivity, health and welfare of poultry following ban or restriction of in-feed antibiotic use. Depending upon the types of PBC, they possess antimicrobial, digestive enzyme secretion stimulation, antioxidant and many pharmacological properties, which are responsible for beneficial effects in poultry production. Moreover, they may also improve the intestinal barrier function and nutrient transport. In this review, the effects of different PBC on the barrier function, permeability of intestinal epithelia and their mechanism of actions are discussed, focusing on poultry feeding. Dietary PBC may regulate intestinal barrier function through several molecular mechanisms by interacting with different metabolic cascades and cellular transcription signals, which may then modulate expressions of genes and their proteins in the tight junction (e.g., claudins, occludin and junctional adhesion molecules), adherens junction (e.g., E-cadherin), other intercellular junctional proteins (e.g., zonula occludens and catenins), and regulatory proteins (e.g., kinases). Interactive effects of PBC on immunomodulation via expressions of several cytokines, chemokines, complement components, pattern recognition receptors and their transcription factors and cellular immune system, and alteration of mucin gene expressions and goblet cell abundances in the intestine may change barrier functions. The effects of PBC are not consistent among the studies depending upon the type and dose of PBC, physiological conditions and parts of the intestine in chickens. An effective concentration in diets and specific molecular mechanisms of PBC need to be elucidated to understand intestinal barrier functionality in a better way in poultry feeding.

Effects of Gut Microbiome and Short-Chain Fatty Acids (SCFAs) on Finishing Weight of Meat Rabbits

Understanding how the gut microbiome and short-chain fatty acids (SCFAs) affect finishing weight is beneficial to improve meat production in the meat rabbit industry. In this study, we identified 15 OTUs and 23 microbial species associated with finishing weight using 16S rRNA gene and metagenomic sequencing analysis, respectively. Among these, butyrate-producing bacteria of the family Ruminococcaceae were positively associated with finishing weight, whereas the microbial taxa related to intestinal damage and inflammation showed opposite effects. Furthermore, interactions of these microbial taxa were firstly found to be associated with finishing weight. Gut microbial functional capacity analysis revealed that CAZymes, such as galactosidase, xylanase, and glucosidase, could significantly affect finishing weight, given their roles in regulating nutrient digestibility. GOs related to the metabolism of several carbohydrates and amino acids also showed important effects on finishing weight. Additionally, both KOs and KEGG pathways related to the membrane transportation system and involved in aminoacyl-tRNA biosynthesis and butanoate metabolism could act as key factors in modulating finishing weight. Importantly, gut microbiome explained nearly 11% of the variation in finishing weight, and our findings revealed that a subset of metagenomic species could act as predictors of finishing weight. SCFAs levels, especially butyrate level, had critical impacts on finishing weight, and several finishing weight-associated species were potentially contributed to the shift in butyrate level. Thus, our results should give deep insights into how gut microbiome and SCFAs influence finishing weight of meat rabbits and provide essential knowledge for improving finishing weight by manipulating gut microbiome.