Effects of feeding sulfate trace minerals above recommendations on nutrient digestibility, rumen fermentation, lactational performance, and trace mineral excretion in dairy cows

Most trace minerals (TM) are fed above dairy cow requirements in commercial herds but their fate and effects on dairy cows have not been well documented. In this study, we evaluated the effects of feeding short-term sulfate TM above recommendations on apparent total-tract digestibility of nutrients, rumen fermentation characteristics, serum concentrations, milk yield and composition as well as milk, fecal, and urinary TM excretion in mid-lactation dairy cows. Eight multiparous Holstein cows [average body weight: 684 (SD: 29) kg at 82 (SD: 10) days in milk] in a quadruple 2 × 2 crossover design were fed a basal diet, differing in sulfate TM supplement concentrations, to provide either 0.11, 17, and 63 (control; CON) or 0.95, 114, and 123 (high trace minerals; HTM) mg of dietary Co, Mn, and Zn/kg of dry matter, respectively. Each experimental period had a 21-d adaptation to the diet, followed by a 10-d sample collection period. Feed ingredients and total feces and urine were collected during 4 consecutive d and rumen fluid was collected 0, 1, 2, 4, and 6 h relative to feeding. Milk yield was recorded daily and milk samples were collected on 4 consecutive milkings. Ingestion of Co, Mn, and Zn was higher for HTM compared with CON group by 216, 233, and 93%, respectively. Dry matter intake averaged 25.0 (SE = 0.6) kg/d, and apparent total-tract digestibility of major nutrients was similar between treatments. There was no measurable effect of HTM on ruminal pH, major volatile fatty acids, and protozoa counts. Isovalerate molar proportion was 9.4% greater for HTM compared with CON group. Neither milk yield (43.5 kg/d; SE = 0.8) nor milk fat and protein concentrations differed between treatments. Milk urea nitrogen concentration was significantly higher for HTM (11.7 mg/dL) compared with CON group (9.7 mg/dL; SE = 0.7). Fecal excretion of Co, Mn, and Zn increased by 223, 198, and 75%, respectively, for HTM compared with CON group. Urinary excretions of TM were marginal compared with feces, and only urinary Co and Mn were significantly higher for HTM than CON cows as similarly obtained for serum Co and Mn concentrations. Milk TM yields were not modified by treatments. In summary, short-term dietary sulfate TM supply over the recommendation did not improve cow performance but significantly increased fecal TM excretion, which could have impacts on TM accumulation in soils where manure is applied and could potentially result in leaching into nearby watersheds. Further studies are needed to evaluate the impact of high fecal TM excretion on the environment using the One Health approach. Moreover, the impacts of TM oversupply on milk production and cow health should be evaluated by long-term experiments.

Effects of Black Soldier Fly (Hermetia illucens L., BSF) Larvae Addition on In Vitro Fermentation Parameters of Goat Diets

The purpose of this experiment was to evaluate the effects of different levels of BSF on rumen in vitro fermentation gas production, methane (CH4) production, ammonia nitrogen (NH3-N), and volatile fatty acids (VFAs). The experiment comprised four treatments, each with five replicates. The control group contained no BSF (BSF0), and the treatment groups contained 5% (BSF5), 10% (BSF10), and 15% (BSF15) BSF, respectively. Results showed that at 3 h, 9 h, and 24 h, gas production in BSF5 and BSF10 was significantly higher than in BSF0 and BSF15 (p < 0.05). Gas production in BSF5 and BSF10 was higher than in BSF0, while gas production in BSF15 was lower than in BSF0. At 6 h and 12 h, CH4 emission in BSF15 was significantly lower than in the other three groups (p < 0.05). There were no differences in the pH of in vitro fermentation after BSF addition (p > 0.05). At 3 h, NH3-N levels in BSF10 and BSF15 were significantly higher than in BSF0 and BSF5 (p < 0.05). At 6 h, NH3-N levels in BSF5 and BSF10 were significantly higher than in BSF0 and BSF15 (p < 0.05). Acetic acid, propionic acid, butyric acid, and total VFAs in BSF0, BSF5, and BSF10 were significantly higher than in BSF15 (p < 0.05). In conclusion, gas production, CH4 emission, NH3-N, acetic acid, propionic acid, butyric acid, and VFAs were highest in BSF5 and BSF10 and lowest in BSF15.

Supplemental trace minerals as complexed or inorganic sources for beef cattle during the receiving period

To investigate effects of inorganic or complexed trace mineral source (zinc, copper, manganese, and cobalt) on receiving period performance and morbidity, crossbred beef heifer calves (n = 287) arriving on three delivery dates were used in a 42-d receiving trial. Heifers were processed after arrival, stratified by day -1 body weights (BW) and allocated randomly to eight pens (11 to 13 heifers/pen, 24 pens total). Within truckload, pens were assigned randomly to dietary treatment (n = 12 pens/treatment). Heifers were housed on 0.42-ha grass paddocks, provided ad libitum bermudagrass hay and provided dietary treatments in grain supplements fed daily. Treatments consisted of supplemental zinc (360 mg/d), copper (125 mg/d), manganese (200 mg/d), and cobalt (12 mg/d) from complexed (Zinpro Availa 4, Zinpro Corp. Eden Prairie, MN) or inorganic sources (sulfates). Heifers were observed daily for clinical bovine respiratory disease (BRD). If presenting BRD symptoms and rectal temperature ≥ 40 °C, heifers were deemed morbid and treated with antibiotics. Six heifers/pen were bled to determine serum haptoglobin concentrations on days 0, 14, and 28. Liver biopsies were taken on day 5 ± 2 and 43 ± 1 from three calves selected randomly from each pen for mineral status comparisons. Statistical analyses were performed using the MIXED, GLIMMIX, and repeated measures procedures of SAS 9.4 with truckload as a random effect and pen within truckload specified as subject. There tended to be a treatment by day interaction for BW (P = 0.07). Heifer BW did not differ on day 0 (P = 0.82) and day 14 (P = 0.36), but heifers fed complexed trace minerals had greater BW on day 28 (P = 0.04) and day 42 (P = 0.05). Overall average daily gains were greater for heifers fed complexed trace minerals (P = 0.05; 0.78 vs. 0.70 kg, SE = 0.03). Heifers supplemented with inorganic trace minerals had greater BRD incidence (P = 0.03; 58 vs. 46%, SE = 3.6). Haptoglobin concentrations decreased throughout the trial (P < 0.001), and heifers fed complexed trace minerals tended to have a decrease in haptoglobin concentrations (P = 0.07). The source of trace mineral supplementation had no effect (P ≥ 0.20) on liver mineral concentrations and there were no treatment × day interactions (P ≥ 0.35). In conclusion, supplementing diets for the first 42 d after arrival with complexed trace mineral sources improved heifer performance as compared to heifers supplemented with inorganic trace minerals.

Effects of sources and levels of dietary supplementary manganese on growing yak's in vitro rumen fermentation

Introduction

Manganese (Mn) is an essential trace element for livestock, but little is known about the optimal Mn source and level for yak.

Methods

To improve yak's feeding standards, a 48-h in vitro study was designed to examine the effect of supplementary Mn sources including Mn sulfate (MnSO₄), Mn chloride (MnCl₂), and Mn methionine (Met-Mn) at five Mn levels, namely 35 mg/kg, 40 mg/kg, 50 mg/kg, 60 mg/kg, and 70 mg/kg dry matter (includes Mn in substrates), on yak's rumen fermentation.

Results

Results showed that Met-Mn groups showed higher acetate (p < 0.05), propionate, total volatile fatty acids (p < 0.05) levels, ammonia nitrogen concentration (p < 0.05), dry matter digestibility (DMD), and amylase activities (p < 0.05) compared to MnSO4 and MnCl2 groups. DMD (p < 0.05), amylase activities, and trypsin activities (p < 0.05) all increased firstly and then decreased with the increase of Mn level and reached high values at 40-50 mg/kg Mn levels. Cellulase activities showed high values (p < 0.05) at 50-70 mg/kg Mn levels. Microbial protein contents (p < 0.05) and lipase activities of Mn-Met groups were higher than those of MnSO4 and MnCl2 groups at 40-50 mg/kg Mn levels.

Discussion

Therefore, Mn-met was the best Mn source, and 40 to 50 mg/kg was the best Mn level for rumen fermentation of yaks.

Meta-analysis of the effects of sulfate versus hydroxy trace mineral source on nutrient digestibility in dairy and beef cattle

Trace mineral (TM) source can potentially alter nutrient digestibility through effects on microbial populations. A meta-analysis was conducted to determine whether sulfate versus hydroxy (IntelliBond) sources of supplemental Cu, Zn, and Mn had any effect on dry matter intake (DMI), dry matter digestibility, and neutral detergent fiber (NDF) digestibility. All available cattle studies (8 studies, 12 comparisons) were used to estimate the effect size (hydroxy mean - sulfate mean). Factors included in the analysis were method of digestibility analysis (total collection, marker-based, or 24 h in situ), study design (randomized design or Latin square), beef (n = 5) versus dairy (n = 7) cattle, and days on treatment; these factors were retained when P < 0.05. Dry matter digestibility was increased by hydroxy TM in beef (1.64 ± 0.35 units) but not in dairy models (0.16 ± 0.13 units) relative to sulfate TM. The NDF digestibility increased significantly with hydroxy versus sulfate TM, but digestibility assessment method influenced this response. Studies using total collection or undigested NDF as a flow marker showed a significant increase (2.68 ± 0.40 units and 1.08 ± 0.31 units, respectively) in NDF digestibility for hydroxy versus sulfate TM; but studies utilizing 24-h in situ incubation did not detect any change (-0.03 ± 0.23 units). These observations may reveal differences in precision of measurement or may indicate mineral effects beyond the rumen; total collection is considered the gold standard method. Hydroxy TM did not affect DMI per animal or per unit of body weight relative to sulfate TM. In conclusion, feeding hydroxy versus sulfate TM does not appear to affect DMI but, depending on type of cattle and method of measurement, can increase dry matter digestibility and NDF digestibility, which may be explained by differences in solubility of the TM sources in rumen, differentially affecting fermentation.

Feeding reduced levels of trace minerals in proteinate form and selenium-yeast to transition cows: Performance, trace minerals, and antioxidant status, peripheral neutrophil activity, and oocyte quality

An experiment was conducted to evaluate the effects of inorganic trace minerals (TM) and reduced levels of TM by using proteinate forms of Co, Zn, Mn, and Cu, and Se-yeast in diets of transition cows on performance, TM concentrations in colostrum, plasma, and liver, blood metabolites, antioxidant status, peripheral neutrophil activity, and oocyte quality. Thirty-two Holstein cows (22 multiparous and 10 primiparous cows) were enrolled in this study from 30 d before the expected calving date to 56 DIM. Cows were blocked according to body condition score, parity, and previous milk yield and randomly assigned to one of the following treatments: control (CON), with TM (Zn, Cu, Mn, and Co) supplied in form of sulfate and Se as sodium selenite to meet or exceed requirement estimates of the National Research Council; and proteinate trace minerals (PTM), with TM supplied bound with AA and peptides at 50% of CON levels and inorganic Se replaced with Se-yeast at 100% of CON level. Treatments were supplied until 56 DIM. Eight cows were removed from the study because of early calving (n = 3) or health issues (n = 5); thus, data of 24 cows (16 multiparous and 8 primiparous cows) were used in the statistical analysis. No differences between treatments were detected on nutrient intake or digestibility. Total excretion of purine derivatives was decreased when feeding PTM during the prepartum period. Feeding reduced levels of TM in proteinate form resulted in greater yield of milk (27.7 and 30.9 kg/d for CON and PTM, respectively) and protein (0.890 and 0.976 kg/d) between wk 5 and 8 of lactation. No treatment differences were detected for feed efficiency, milk somatic cell count, and milk urea nitrogen. Cows fed PTM had lower milk fat concentration during the 56 d of evaluation (4.08 and 3.74% for CON and PTM, respectively). Selenium concentration was greater in colostrum of cows fed PTM compared with CON (48.5 and 71.3 µg/L for CON and PTM, respectively), whereas Zn, Cu, and Mn concentrations were not different. Cows fed PTM showed lower liver Cu concentration compared with CON (51.4 and 73.8, respectively). Plasma concentrations of Mn and Zn were lower, but plasma Se concentration tended to be higher with PTM treatment. Feeding PTM resulted in greater blood concentrations of urea-N (16.6 and 18.2 mg/dL for CON and PTM, respectively) and β-hydroxybutyrate (0.739 and 0.940 mmol/L). Counts of lymphocytes were higher with PTM but counts of monocytes were lower in complete blood cell count. No differences were observed in serum concentrations of superoxide dismutase and glutathione peroxidase. No differences were detected in phagocytosis and oxidative burst potential of neutrophils after incubation with bacteria. Cows fed PTM had fewer viable oocytes per ovum pick-up in comparison with CON (8.00 and 11.6). Feeding PTM to transition cows may sustain performance without altering neutrophil activity despite some alterations in blood TM concentrations. More studies should be performed to evaluate production and fertility measurements when reducing TM dietary levels by using proteinate forms and Se-yeast with larger number of animals.

In Vitro Supplementation of Copper Modulates the Functional Th1/Th2 Phenotype of Peripheral Blood Mononuclear Cells in Cattle

Simple Summary

This study investigated the association of copper levels and the appearance of blood monocytes, a white blood cell. One type of monocytes (M1) supports cellular immunity and the M2 monocyte helps the immune system through antibodies. Five samples of cow monocytes (PBMCs) were incubated in different levels of copper; 0, 4, 8 and 16 μM. After stimulation under three different conditions, we stained them for CD14 and CD16 to allow typing of the monocytes (M1 and M2). M1 function was also measured through nitric oxide (NO) production. The results showed a significant reduction in viability of the monocytes with increased copper (p < 0.001). Increasing copper resulted in more M1 type monocytes in cows older than 4 years (p = 0.001). CD14 expression affected both CD16 (M2) expression and NO production. For CD16 expression, there was a further significant negative effect of copper levels in cows older than 4 years, whereas NO was not affected by the varying copper levels. In our small sample, monocytes incubating in a higher copper environment showed a stronger M1 support for better cellular immunity containing intracellular infections more effectively. In the live animal low copper levels could possibly affect progression of a bacterial infection to clinical disease.

Abstract

This study investigated the association of copper levels and monocyte plasticity between M1 (CD14⁺ CD16⁻) and M2 (CD14⁻ CD16⁺⁺) phenotypes. Five samples of female bovine PBMCs were incubated in 0, 4, 8 and 16 μM copper and stimulated (PPD-A, TLR- 2 ligand (Pam₃CSK₄), or media alone) before they were washed and stained for cell surface expression analysis by flow cytometry. M1 function was measured through nitric oxide production using a Griess assay. Flow cytometry analysis showed a significant reduction in viability with increased copper (p < 0.001). Increasing copper had a significant impact on CD14 expression (p = 0.026) and in cows older than 4 years copper levels positively affected CD14 expression (p = 0.001), whereas in animals of four years or younger, Cu did not affect the CD14 expression (p = 0.701 and 0.939, respectively). CD14 expression affected both CD16 expression and NO production. For CD16 expression, there was a further significant negative effect of copper levels in cows older than 4 years, NO was not affected by varying copper levels. In our small sample, monocytes in the presence of a higher copper environment showed a stronger M1 support for better cellular immunity which might contain intracellular infections more effectively. To test this, a randomised clinical trial will be required to determine whether copper supplementation could prevent progression to Johne’s disease in MAP infected cows.

Mineral status and enteric methane production in dairy cows during different stages of lactation

BACKGROUND

Lactating dairy cows are the greatest livestock contributor of methane, a major global greenhouse gas (GHG). However, good feeding management with adequate mineral intake can offers an effective approach to maintaining high levels of milk production and the health of dairy cows over the entire course of lactation, while also helping to reduce methane emission. The study described here investigated the plasma concentrations of both macroelements (Ca, Na, K, Mg, P) and microelements (Zn, Cu, Fe, Mn), as well as enteric methane emission and milk composition in high-yielding dairy cows in different lactation periods. The experiment was performed on Holstein-Friesian dairy cows with the average milk yield of 41 (± 9) L/day in a Polish commercial farm with modern dairy systems. A total of thirty high-yielding dairy cows were randomly assigned into three groups differing by lactation stage: early stage (Early, days 25-100), middle stage (Middle, days 101-250), and late stage (Late, day 250 and later). Dietary treatment for all cows was a total mixture ration (TMR) with maize and alfalfa silage the main forage components.

RESULTS

The greatest milk yield and methane production were recorded in early-stage lactating cows, but the greatest methane intensity per kg of corrected milk was recorded in the late stage of lactation. Plasma concentrations of macroelements and microelements did not differ by lactation stages, but increased plasma concentrations of Zn and Fe and decreased plasma levels of Mg were noted during lactation. A positive correlation was found between plasma levels of Mg and other macroelements (Ca, Na, K), and between the concentrations of Fe and Zn, P in plasma, but no correlation between methane emission and mineral status was detected in the different lactation stages.

CONCLUSIONS

Our results showed different mineral requirements and enteric methane emissions in each lactation stage. The feeding strategy and mineral utilization were adequate to maintain the health, mineral status, and milk production of the Holstein cows during the entire lactation period, and suggest an effective way of reducing methane emission.

Copper, iron, zinc and tannin concentrations throughout the digestive tract of tropical goats and sheep fed a high-fibre tannin-rich diet

The dry season in tropical regions urges livestock to feed on nutritionally very poor diets. It has not been explored how tropical sheep-assumed grazers-and tropical goats-intermediate browsers-cope with a high-fibre tannin-rich diet. This study was designed to determine the effects of a high-fibre and tannin-rich diet on the flow of important microminerals iron (Fe), zinc (Zn) and copper (Cu) throughout the digestive tract of tropical sheep and goats. The feeding trial was set up with twelve adult male animals, six sheep with mean body weight (BW) of 30.3 ± 1.6 kg and six goats with mean BW of 26.4 ± 2.2 kg. The feed consisted of 36% leaves of Millettia ferruginea, 61% hay and 3% concentrate and was offered at 3% of BW (all on dry matter (DM) basis). The total faecal collection was carried out for 7 consecutive days. At the end of the experimental period, the animals were slaughtered to collect liver and digesta samples from the gastrointestinal tract. Feed, digesta and faecal samples underwent analysis of Fe, Zn, and Cu and total tannins (TT). Goats had significantly higher reticulum Cu concentrations expressed on DM as compared to sheep. Faecal Cu concentrations were higher for goats compared to sheep. Reticulum and colon digesta Zn levels were higher in goats than sheep. Abomasum and colon Fe levels were higher in sheep than goats when expressed on DM. These results suggest differences in feed intake, micromineral absorption, secretion and excretion between sheep and goats, pointing to a divergent mineral metabolism as an adaptation to the challenge of a dry season diet having very low nutritive value.

Impact of Zinc and/or Herbal Mixture on Ruminal Fermentation, Microbiota, and Histopathology in Lambs

We investigated the effect of diets containing organic zinc and a mixture of medicinal herbs on ruminal microbial fermentation and histopathology in lambs. Twenty-eight lambs were divided into four groups: unsupplemented animals (Control), animals supplemented with organic zinc (Zn, 70 mg Zn/kg diet), animals supplemented with a mixture of dry medicinal herbs (Herbs, 100 g dry matter (DM)/d) and animals supplemented with both zinc and herbs (Zn+Herbs). Each lamb was fed a basal diet composed of meadow hay (700 g DM/d) and barley (300 g DM/d). The herbs Fumaria officinalis L. (FO), Malva sylvestris L. (MS), Artemisia absinthium L. (AA) and Matricaria chamomilla L. (MC) were mixed in equal proportions. The lambs were slaughtered after 70 d. The ruminal contents were used to determine the parameters of fermentation in vitro and in vivo and to quantify the microbes by molecular and microscopic methods. Samples of fresh ruminal tissue were used for histopathological evaluation. Quantitative analyses of the bioactive compounds in FO, MS, AA, and MC identified 3.961, 0.654, 6.482, and 12.084 g/kg DM phenolic acids and 12.211, 6.479, 0.349, and 2.442 g/kg DM flavonoids, respectively. The alkaloid content in FO was 6.015 g/kg DM. The diets affected the levels of total gas, methane and n-butyrate in vitro (P < 0.046, < 0.001, and < 0.001, respectively). Relative quantification by real-time PCR indicated a lower total ruminal bacterial population in the lambs in the Zn and Zn+Herbs groups than the Control group (P < 0.05). The relative abundances of Ruminococcus albus, R. flavefaciens, Streptococcus bovis, and Butyrivibrio proteoclasticus shifted in the Zn group. Morphological observation found a focally mixed infiltration of inflammatory cells in the lamina propria of the rumen in the Zn+Herbs group. The effect of the organic zinc and the herbal mixture on the parameters of ruminal fermentation in vitro was not confirmed in vivo, perhaps because the ruminal microbiota of the lambs adapted to the zinc-supplemented diets. Long-term supplementation of a diet combining zinc and medicinal herbs, however, may negatively affect the health of the ruminal epithelium of lambs.

Performance, rumen fermentation, blood minerals, leukocyte and antioxidant capacity of young Holstein calves receiving high-surface ZnO instead of common ZnO

This study was conducted to assess the effect of feeding high-surface ZnO instead of common ZnO on the performance, rumen fermentation, blood minerals, leukocytes and antioxidant capacity of pre- and post-weaning calves. Thirty male suckling Holstein calves were allotted to one of three experimental groups (10 replicates) in a completely randomised design. Calves received: (1) a low Zn diet without Zn supplementation (control diet), (2) a high Zn diet containing 50 mg supplementary Zn/kg dry matter (DM) as common ZnO or (3) a high Zn diet containing 50 mg supplementary Zn/kg DM as high-surface ZnO (nano-ZnO). The control diet contained a native Zn content of 35.5, 34.7 or 33.7 mg/kg DM for the age periods of 7 to 30, 31 to 70 and 71 to 100 d, respectively. Supplementation of the diet with Zn did not change the dry matter intake (DMI) of calves during d 7 to 30 but increased the ADG in this period (p < 0.05). During age periods of 31 to 70 and 71 to 100 d, DMI and ADG of the Zn supplemented calves were higher (p < 0.05) than the control animals. The nutrient digestibility and the concentration of rumen volatile fatty acids were positively affected (p < 0.05) and the rumen ammonia-N concentration decreased (p < 0.05) by dietary Zn supplementation. Furthermore, the incidence of diarrhoea and pneumonia was lower in calves receiving the Zn supplemented diets. Irrespective of ZnO source, the blood total antioxidant capacity, leukocyte and haematocrit levels significantly increased (p < 0.05) with the ZnO supplemented diets. The post-weaning DMI, nutrient  digestibility and blood haematocrit levels were higher in calves receiving high-surface ZnO, compared to those supplemented with common ZnO. With inclusion of the Zn sources in pre- and post-weaning diets, the blood Zn concentration increased (p < 0.05), but the blood Cu, Fe, Ca, P and Mg levels remained unchanged. Regardless of source, dietary supplementation of young calves with ZnO improved the performance and decreased rumen ammonia-N and the incidence of diseases. Moreover, high-surface ZnO had advantages over common ZnO in increasing the post-weaning feed intake, digestibility and blood Zn concentration.

Sources and Levels of Trace Elements Influence Some Blood Parameters in Murrah Buffalo (Bubalus bubalis) Calves

Sources of supplemental minerals in the diet of animals are of important significance. Bio-availability of organic sources is believed to be more in the body as compared to regularly used inorganic sources and hence environment-friendly due to reduced mineral excretion, which in turn reduces their requirements in the diet as well. Twenty-four male Murrah buffalo (Bubalus bubalis) calves (about 18-20 months of age and 318.54 ± 8.85 kg body weight) were divided randomly into four groups of six animals each. In the control group (C, InOrg100) zinc (Zn), copper (Cu), and manganese (Mn) were supplemented through an inorganic source, while in treatment groups, organic source at the rate of 50, 75, or 100% (in groups T1 (Org50), T2 (Org75), and T3 (Org100), respectively) was fed at level as supplemented in the control group. Feeding was continued for a period of 180 days with blood sampling at day 0 followed by a regular interval of 45 days. Plasma samples were analyzed for trace elements Cu, Mn, Zn, and iron (Fe), total antioxidant status, ceruloplasmin, and superoxide dismutase (SOD) with cell-mediated and humoral immune response. Plasma levels of different trace minerals like Fe, Mn, and Cu remained unaffected with two sources and different levels of organic minerals, except the level of Zn, which showed higher (P < 0.05) levels in the group Org100 compared to others, and remained indicative of higher bio-availability through the organic source. The concentration of plasma total antioxidants indicated no adverse effect on the reduction of supplemental levels up to half of these minerals. Also, the level of plasma SOD was high (P < 0.05) at each level of the organic source as compared to the 100% level of the inorganic source. Immune response in respect of cell-mediated as well as humoral immunity did not show any reduction in different groups. The study indicated beneficial impacts of the organic source in the form of superior plasma Zn level as well as SOD concentrations. In addition, no negative effect on most of the studied parameters was observed after reducing supplemental trace minerals to half indicating higher bio-availability of organic trace minerals.

Zinc AA supplementation alters yearling ram rumen bacterial communities but zinc sulfate supplementation does not

 Despite the body of research into Zn for human and animal health and productivity, very little work has been done to discern whether this benefit is exerted solely on the host organism, or whether there is some effect of dietary Zn upon the gastrointestinal microbiota, particularly in ruminants. We hypothesized that (i) supplementation with Zn would alter the rumen bacterial community in yearling rams, but that (ii) supplementation with either inorganically sourced ZnSO4, or a chelated Zn AA complex, which was more bioavailable, would affect the rumen bacterial community differently. Sixteen purebred Targhee yearling rams were utilized in an 84-d completely randomized design, and allocated to one of three pelleted dietary treatments: control diet without fortified Zn (~1 × NRC), a diet fortified with a Zn AA complex (~2 × NRC), and a diet fortified with ZnSO4 (~2 × NRC). Rumen bacterial community was assessed using Illumina MiSeq of the V4 to V6 region of the 16S rRNA gene. One hundred and eleven OTUs were found with > 1% abundance across all samples. The genera Prevotella, Solobacterium, Ruminococcus, Butyrivibrio, Olsenella, Atopobium, and the candidate genus Saccharimonas were abundant in all samples. Total rumen bacterial evenness and diversity in rams were reduced by supplementation with a Zn AA complex, but not in rams supplemented with an equal concentration of ZnSO4, likely due to differences in bioavailability between organic and inorganically sourced supplement formulations. A number of bacterial genera were altered by Zn supplementation, but only the phylum Tenericutes was significantly reduced by ZnSO4 supplementation, suggesting that either Zn supplementation formulation could be utilized without causing a high-level shift in the rumen bacterial community which could have negative consequences for digestion and animal health.

Modulation of ruminal and intestinal fermentation by medicinal plants and zinc from different sources

Two experiments were conducted on sheep to determine the effect of dietary supplementation with zinc and a medicinal plant mixture on haematological parameters and microbial activity in the rumen and large intestine. In Experiment 1, 24 male lambs were randomly divided into four groups: One group was fed an unsupplemented basal diet (control), and three groups were fed a diet supplemented with 70 mg Zn/kg diet in the form of Zn sulphate (ZnSO₄ ), a Zn-chelate of glycine hydrate (Zn-Gly) or a Zn-proteinate (Zn-Pro), for five months. The ruminal content was collected separately from each lamb, and batch cultures of ruminal fluid were incubated in vitro with mixture of medicinal plants (Mix) with different roughage:concentrate ratios (800:200 and 400:600, w/w). Bioactive compounds in Mix were quantified by UPLC/MS/MS. In Experiment 2, four sheep were fed a diet consisting of meadow hay and barley grain (400:600, w/w), with Zn-Gly (70 mg Zn/kg diet), Mix (10% replacement of meadow hay) or Zn-Gly and Mix (Zn-Gly-Mix) as supplements in a Latin square design. Mix decreased total gas (p < 0.001) and methane (p < 0.01) production in vitro. In Experiment 1, caecal isobutyrate and isovalerate concentrations varied among the dietary treatments (p < 0.01). The isovalerate concentration of the zinc-supplemented groups in the distal colon was higher (p < 0.001) compared with the control. In Experiment 2, the molar proportion of isobutyrate was the highest in the faeces of the sheep fed the diet with Zn-Gly-Mix (p < 0.01). The plasma zinc concentration was higher in the groups fed a diet supplemented with zinc (p < 0.001). The haematological profile and antioxidant status did not differ between the dietary groups (p > 0.05). The diets containing medicinal plants and organic zinc thus helped to modulate the characteristics of fermentation in ruminants.