Effects of supplemental zinc concentration on cellulose digestion and cellulolytic and total bacterial numbers in vitro

Impact of 48-h water and feed deprivation and hydroxychloride sources of copper and zinc on the metabolism and performance of grazing Nellore cattle during the dry period

Procedures such as transport and marketing can subject animals to water and feed deprivation and impair animal health and performance. Maintaining the mineral status of animals under these conditions can bring benefits to health and performance. The use of hydroxychloride mineral sources can improve mineral status, nutrient digestibility and performance. Two studies were conducted to investigate how the supplementation of 02 trace mineral sources of Cu and Zn and 48-hour water/feed deprivation would affect the performance and metabolism of grass-fed beef cattle. In the first study, 20 castrated and rumen-canulated Nellore steers (BW = 350 ± 132 kg; 20 m) were distributed in individual pens, in a 2 × 2 factorial arrangement: supplemental Cu and Zn sources from inorganic vs hydroxychloride (HTM) and 48-hours deprivation (WFD) vs unrestricted (WFU) access to water and feed. The 57d of study was divided into two periods: (1) Adaptation from -21d to -1d and (2) evaluation from 0d to 36d. Interaction between deprivation × period was detected (P < 0.05) for digestibility of DM (DMD), organic matter (OMD), neutral detergent fiber (NDFD), and acid detergent fiber (ADFD). Deprivation increased DMD, OMD, NDFD, and ADFD immediately after the deprivation period (3-5d), but impaired digestibility at longer periods such as 11-13d and 32-34d. DM (DMI) and nutrient intake (P = 0.075), as well as NDFD were higher in HTM. Several ruminal parameters were affected by deprivation: short-chain fatty acids concentration decreased, while rumen pH increased (deprivation × time; P < 0.05); decreased propionate, butyrate and increased isobutyrate, isovalerate, and valerate in WFD (deprivation × time; P < 0.05), respectively. In the second study, eighty-four intact Nellore males (BW = 260 ± 35 kg) were blocked by BW and randomly assigned to Urochloa brizantha cv. Marandu paddocks for 131d in a 2 × 2 factorial arrangement. Liver Cu was higher in WFU/HTM animals (mineral × deprivation; P < 0.05). Interaction between deprivation × period (P < 0.05) was detected for BW and average daily gain (ADG). On 2d and 12d after deprivation, WFD increased ADG and recovered the BW lost. In conclusion, water and feed deprivation imposed in these trials were able to impact several nutrient digestibility and ruminal fermentation parameters in short- and long-term. Performance was not affected by the studied factors. Furthermore, supplementation with sources of Cu and Zn hydroxychloride increased Cu in the liver and tended to increase DMI and NDFD.

The combined effect of ultrafine particles of cobalt and manganese oxides and Origanum vulgare herb extract on ruminal digestion in vitro

Background and Aim

At present, detailed studies are being conducted to confirm the safety of the use of metal-containing ultrafine particles (UFP) in animal feeding, preventing the possibility of negative effects on productive qualities and physiological state, as well as on the environment and final consumer, that is, humans. Thus, the purpose of this research was to study the safety of cobalt- and manganese-containing UFP (UFP Co3O4, Mn2O3 UFP) together with Origanum vulgare (PB) herb extract in a bioluminescence inhibition test, as well as the effect of this composition on ruminal digestion in vitro.

Materials and Methods

The safety of the studied samples was determined using a multifunctional microplate analyzer TECAN Infinite F200 (Tecan Austria GmbH, Austria), recording the luminescence value of the bacterial strain Escherichia coli K12 TG11 (Ecolum, JSC NVO Immunotech, Russia). Dry matter (DM) digestibility studies were performed using the in vitro method on an "artificial rumen" model using an ANKOM Daisy II incubator unit (AD II; USA). The number of protozoa in ruminal fluid was counted in a Goryaev chamber. The bacterial mass was assessed by differential centrifugation followed by drying. This method is based on differences in the sedimentation rate of particles that differ in size and density.

Results

UFP Co3O4 and Mn2O3 at concentrations above 1.5 × 10-5 and 1.9 × 10-3 mol/L, respectively, have a pronounced bactericidal effect, suppressing more than 50% of the luminescence of E. coli K12 TG1. The combined use of UFP metals and plant extract increases the luminescence of the test object, indicating its safety. The combined use of UFP and PB increases the digestibility of feed DM in vitro and the number of protozoa in 1 mL of ruminal fluid; however, the combination of UFP Mn2O3 + PB (13.8%) yielded the best result, which is recommended for further in vivo research.

Conclusion

Origanum vulgare extract reduces the toxicity of UFP Co3O4 and Mn2O3 in vitro, indicating that their combined use is safer.

Optimizing ruminant nutrition: Insights from a comprehensive analysis of silage composition and in vitro gas production dynamics using nonlinear models

Achieving sustainable livestock management necessitates optimizing animal production while minimizing environmental impact. To achieve this, feed efficiency must be enhanced, and nutrition blueprints must be understood. In ruminant nutrition, this is of paramount importance, as it exposes degradation kinetics and nutritional benchmarks, allowing feed management and formulations to be more ecologically balanced. Previous research efforts have focused on exploring the relationship between a restricted set of nutrient parameters and the in vitro gas production dynamics. In the current study, an extensive dataset derived from freeze-dried kefir culture treated white clover silage was used to examine intricate relationships between eight nonlinear models and diverse variables. This dataset contains in vitro gas production data along with nutritional composition, microbial populations, fermentation quality, digestibility, mineral concentration, and fatty acid profiles. Through rigorous application of mathematical models, the performance in capturing gas production dynamics was critically assessed. Among these, the Michaelis‒Menten (MM) and Mitscherlich (MIT) models fit the data well and offer superior predictions of gas production dynamics. Asymptotic gas volume was negatively correlated with crude protein content, emphasizing the influence of protein on gas production. Fiber composition plays a significant role in fermentation kinetics, as evidenced by significant correlations between degradation rate constant and crude protein concentrations. The degradation rate constant of insoluble fraction exhibited significant positive correlations with crude protein and neutral detergent fiber contents. Moreover, mineral content had significant effects on gas production dynamics. Zinc content showed a strong and significant positive correlation with the gas production rate coefficient, underscoring its crucial role in enhancing microbial activity. Conversely, calcium content displayed a significant but weak negative correlation with the final asymptotic gas volume, indicating its potential to modulate gas production. In summury, this study provides detailed insights into the intricate relationship between mathematical models and various variables in rumen fermentation. The MM and MIT models have proven to be robust tools, offering nuanced perspectives on gas production dynamics. These findings pave the path for improving sustainable ruminant nutritional practices and refining feed management strategies.

The enrichment of chocolate byproducts and protected fats with zinc to partially replace corn in diets of early lactation Holstein cows

The present experiment aimed to evaluate the effect of partial replacement of corn with chocolate byproducts, protected fats, or their mixture supplemented with zinc in the diet of lactating cows on feed utilization and lactation performance for 90 days. Fifty multiparous Holstein cows (565±25 kg BW, 3±1 parity, 7±1 days in milk, a previous milk production of 35±2.9 kg/d), were randomly assigned to 5 treatments in a completely randomized design. The control diet contained (per kg DM): 412 g concentrate feed mixture, 412 g corn silage, and 176 g berseem hay. The control diet was supplemented with 1 g of zinc daily (Zinc diet). In the other diets, each kg of crushed corn grain was replaced with (DM basis) 600 g chocolate byproducts (CH diet), 400 g protected fats (PF diet), or 500 g of chocolate byproducts and protected fats mixture (1:1 DM basis) (CHPF diet). Both amounts of protected fats and chocolate byproducts had the same energy concentration as 1 kg of corn. The total mixed ration was prepared and distributed using a horizontal mixer system after mixing for 20 min. Chemical analysis showed that the replacement minimally affected the composition of the total mixed rations. Additionally, treatments did not affect feed intake. Compared to the control treatment, the zinc treatment did not affect milk production, milk composition, or feed efficiency. Increased (P<0.05) daily production of milk and component yields, and feed efficiency as well as fat concentration were observed by the CH, PF and CHPF treatments. Without affecting other measured blood parameters or hematocrit, treatments increased (P<0.05) the concentrations of total proteins, albumin, glucose, cholesterol, triglyceride, and zinc in the blood of cows. Additionally, the CH, PF and CHPF treatments increased (P<0.01) the digestibility of nutrients compared to the control treatment. It is concluded that the addition of zinc to the control did not affect cow performance; however, its addition to chocolate byproducts, protected fats, or their mixture to partially replace corn improved the performance of cows.

Effect of zinc source (zinc sulfate or zinc hydroxychloride) on relative abundance of fecal Treponema spp. in lactating dairy cows

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Cows (n = 24) were fed typical lactating diets that only differed in zinc source inclusion.

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Fecal samples collected from cows were extracted for prokaryotic 16S gene DNA.

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Feeding zinc hydroxychloride decreased the Treponema spp. recovered from fecal samples compared with cows fed zinc sulfate.

Previous research revealed a potential effect of dietary trace mineral source on both ruminal and fecal microbiota. However, the effect of Zn source, specifically, has not previously been considered. Based on reported postruminal solubility, we hypothesized that Zn hydroxychloride would decrease Treponema spp. fecal excretion relative to cows fed Zn sulfate. To test this hypothesis, lactating Holstein cows (n = 24; 685 ± 9 kg of body weight; 159 ± 8 d in milk; parity 3 ± 0.2) were randomly assigned to 1 of 2 dietary treatments: control (75 mg/kg Zn from ZnSO₄) or Zn hydroxychloride (HYD; 75 mg/kg IntelliBond Z; Micronutrients USA LLC). Single fecal grab samples were collected on d 1 before dietary treatments and on d 27 after dietary treatments were applied. Fecal microbial DNA was extracted and sequenced to establish taxonomy using a universal primer for the 16S rRNA gene. Supplementation of HYD decreased the relative abundance of Treponema 2 by 3-fold (14.7% vs. 4.9%). Poor sequencing resolution at the species level limited inference of Treponema spp. toward management or gut health implications of HYD supplementation. However, the inclusion of pathogenic species among Treponema spp. indicates a potential implication of HYD feeding to reduce environmental exposure of the dairy cow to Treponema spp.

Effect of zinc sources and experimental conditions on zinc balance in growing wethers

Three experiments were conducted with growing wethers to evaluate apparent excretion and retention of Zn from various sources. In experiments 1 and 2, Zn-ethylene diamine (ZE), Zn hydroxychloride (ZHYD), Zn-lysine/glutamate (ZAA), and Zn-glycinate (ZG) were used and ZnSO4 (ZS), ZHYD, ZAA, and ZG were used in experiment 3. In experiment 1, eight wethers were used in a replicated 4 × 4 Latin square design. In experiments 2 and 3, 40 wethers were used in a randomized block design. In experiment 1, each period (total four periods) consisted of 14-d diet adaptation and 4 d of total collection of feces and urine. In experiments 2 and 3, wethers received a basal diet for 14 d and received experimental diets for 9 d (diet adaptation), followed by 4 d of total collection of feces and urine. Total collection was conducted in wooden metabolic cages. All data were analyzed using the MIXED procedure of SAS as a Latin square design for experiment 1 and a completed randomized block design for experiments 2 and 3. In all experiments, dry matter intake did not differ among treatments except that it tended to be different in experiment 2. In experiment 1, no difference in Zn excretion (88%) and retention (11%) as proportion of Zn intake was observed among Zn sources. In experiment 2, total tract digestibility of crude protein was greater (P < 0.01) for ZAA than ZE and ZG (82.0% vs. 79.1% and 77.8%, respectively) and greater (P < 0.01) for ZHYD than ZG (80.2% vs. 77.8%). However, total tract digestibility of neutral detergent fiber was low (on average 16%) for all treatments with no difference among treatments in experiment 2. Apparent excretion and retention of Zn as proportion of Zn intake did not differ among treatments, and Zn retention (~1.4% of Zn intake) was very low for all treatments. In experiment 3, ZHYD and ZAA had greater retention of Zn (17.8% vs. 1.5%; P = 0.01) than ZG. Fecal Zn excretion was greater (97.3% vs. 81.2%; P = 0.01) for ZG vs. ZHYD and ZAA, and Zn retention for ZG was only 1.5% of Zn intake. In conclusion, potential increases in Zn absorption and retention were observed for ZHYD and ZAA compared with ZS and ZG in experiment 3 and these differences were not found in experiments 1 and 2. Experiment 1 used a Latin square design and experiment 2 used a diet containing largely undigestible fiber. These experimental conditions may have affected Zn metabolism in wethers. Inconsistent results on Zn balance for ZG among the experiments warrant further studies regarding its bioavailability.

Effect of bis-glycinate bound zinc or zinc sulfate on zinc metabolism in growing lambs

To assess the efficacy of bis-glycinate bound Zn, 36 crossbred wethers (34 ± 2 kg) were sorted by body weight into three groups and stagger started on a Zn-deficient diet (18 mg Zn/kg dry matter [DM]; 22.5% neutral detergent fiber [NDF]) for 45 d prior to a 15-d metabolism period (10 d adaptation and 5 d collection). On day 46, lambs were randomly assigned to dietary treatments (four lambs treatment⁻¹group⁻¹): no supplemental Zn (CON) or 15 mg supplemental Zn/kg DM (ZINC) as Zn sulfate (ZS) or bis-glycinate (GLY; Plexomin Zn, Phytobiotics). Blood was collected from all lambs on days 1, 44, 56, and 61. Liver, jejunum, and longissimus dorsi samples were collected after euthanasia on day 61. Gene expression was determined via quantitative real-time polymerase chain reaction. Data were analyzed using ProcMixed of SAS (experimental unit = lamb; fixed effects = treatment, group, and breed) and contrast statements assessed the effects of supplemental Zn concentration (ZINC vs. CON) and source (GLY vs. ZS). After 15 d of Zn supplementation, plasma Zn concentrations were greater for ZINC vs. CON and GLY vs. ZS (P ≤ 0.01); tissue Zn concentrations were unaffected (P ≥ 0.27). Liver Cu concentrations were lesser for ZINC vs. CON (P = 0.03). Longissimus dorsi Mn concentrations were greater for ZINC vs. CON (P = 0.05) and tended to be lesser for GLY vs. ZS (P = 0.09). Digestibility of DM, organic matter (OM), and NDF was lesser for ZINC vs. CON (P ≤ 0.05); acid detergent fiber digestibility tended to be greater for GLY vs. ZS (P = 0.06). Nitrogen retention (g/d) tended to be greater for GLY vs. ZS (P = 0.10), and N apparent absorption was lesser for ZINC vs. CON (P = 0.02). Zinc intake, fecal output, retention, and apparent absorption were greater for ZINC vs. CON (P ≤ 0.01). Apparent absorption of Zn was −5.1%, 12.8%, and 15.0% for CON, ZS, and GLY, respectively. Nitrogen and Zn retention and apparent absorption were not correlated for CON (P ≥ 0.14) but were positively correlated for ZINC (retention: P = 0.02, r = 0.52; apparent absorption: P < 0.01, r = 0.73). Intestinal expression of Zn transporter ZIP4 was lesser for ZINC vs. CON (P = 0.02). Liver expression of metallothionein-1 (MT1) tended to be greater for GLY vs. ZS (P = 0.07). Although Zn apparent absorption did not differ between sources (P = 0.71), differences in post-absorptive metabolism may be responsible for greater plasma Zn concentrations and liver MT1 expression for GLY-supplemented lambs, suggesting improved bioavailability of GLY relative to ZS.

Trace mineral source impacts rumen trace mineral metabolism and fiber digestion in steers fed a medium-quality grass hay diet

Twelve Angus steers (BW 452.8 ± 6.1 kg) fitted with ruminal cannulae were used to determine the impact of trace mineral (TM) source on digestibility, ruminal volatile fatty acid (VFA) composition, ruminal soluble concentrations of Cu, Zn, and Mn, and relative binding strength of trace minerals located in the rumen insoluble digesta fraction. Steers were fed a medium-quality grass hay diet (DM basis: 10.8% CP, 63.1% neutral detergent fiber [NDF], 6.9 mg Cu/kg, 65.5 mg Mn/kg, and 39.4 mg Zn/kg) supplemented with protein for 21 d. Treatments consisted of either sulfate (STM) or hydroxy (HTM) sources (n = 6 steers/treatment) to provide 20, 40, and 60 mg supplemental Cu, Mn, and Zn/kg DM, respectively. Following a 21-d adaptation period, total fecal output was collected for 5 d. Dry matter (P < 0.07) and CP (P < 0.06) digestibility tended to be reduced, and NDF (P < 0.04) and acid detergent fiber (ADF) (P < 0.05) digestibility were reduced in STM- vs. HTM-supplemented steers. On day 6, ruminal fluid was collected at 0, 2, and 4 h post-feeding and analyzed for VFA. There were no treatment x time interactions for VFA. Steers receiving HTM had less (P < 0.02) molar proportions of butyric acid and greater (P < 0.05) total VFA concentrations than STM-supplemented steers. Steers were then fed the same diet without supplemental Cu, Zn, or Mn for 14 d. On day 15 steers received a pulse dose of 20 mg Cu, 40 mg Mn, and 60 mg Zn/kg DM from either STM or HTM (n = 6 steers/treatment). Ruminal samples were obtained at 2-h intervals starting at -4 and ending at 24 h relative to dosing. There was a treatment x time interaction (P < 0.03) for ruminal soluble Cu, Mn, and Zn concentrations. Ruminal soluble mineral concentrations were greater (P < 0.05) for Cu at 4, 6, 8, 10, 12, and 14 h; for Mn at 4 and 6 h; and for Zn at 4, 6, and 8 h post-dosing in STM compared with HTM-supplemented steers. Copper concentrations were greater (P < 0.05) at 12 and 24 h and Zn concentrations in ruminal solid digesta were greater at 24 h in HTM-supplemented steers. Upon dialysis against Tris-EDTA, the percent Zn released from digesta was greater (P < 0.05) at 12 h (P < 0.03) and 24 h (P < 0.05), and the percent Cu released was greater (P < 0.02) at 24 h post-dosing in HTM steers when compared with STM-supplemented steers. Results indicate that Cu and Zn from HTM have low solubility in the rumen and appear to be less tightly bound to ruminal solid digesta than Cu and Zn from STM. The lower ruminal soluble concentrations of Cu and Zn in steers given HTM were associated with greater fiber digestibility.

Effects of prepartum zinc-methionine supplementation on feed digestibility, rumen fermentation patterns, immunity status, and passive transfer of immunity in dairy cows

The aim of this study was to determine the effects of prepartum supplementation of zinc-methionine (Zn-Met) on feed digestibility, rumen fermentation patterns, and immunity status in dams and passive immunity transfer in their calves. A randomized complete design was used in this study. Forty multiparous Holstein dairy cows in late pregnancy (60 d before the expected calving date) were blocked by parity (2.1 ± 0.3), body weight (651 ± 52 kg), and expected calving date, and randomly assigned to 1 of 4 treatments. Cows were supplemented with Zn as Zn-Met at 0, 20, 40, or 60 mg/kg of dry matter (DM) from 60 d before expected calving date to the calving day. Though the nutrient digestibility was not affected by Zn supplementation, DM intake, Zn digestibility, and Zn deposition increased linearly with increasing Zn-Met supplementation. Ruminal pH and molar proportion of individual volatile fatty acids were similar, whereas a linear decrease and increase were observed in ruminal ammonia and microbial crude protein concentration, respectively, with increasing Zn-Met supplementation. Maternal serum concentration of alkaline phosphatase, carboxypeptidase, Cu and Zn superoxide dismutase, and total antioxidant capacity were greater in cows supplemented with >40 mg of Zn/kg of DM compared with the control group. With increasing Zn-Met supplementation, maternal blood concentration of IL-1 decreased linearly, whereas IL-2 and IL-6 increased linearly, and no differences were observed in IL-4. Concentration of nonesterified fatty acids and β-hydroxybutyric acids in maternal blood was similar between treatments. No difference was observed in colostrum composition with increasing Zn-Met supplementation. Concentration of Zn and immunoglobulins (including IgA, IgG, and IgM) in maternal blood did not differ among treatments. However, Zn concentration in colostrum and blood of calves increased linearly. The concentration of IgA and IgM in colostrum increased linearly with increasing Zn-Met supplementation, whereas no differences in immunoglobulins were observed in calf blood. In conclusion, Zn supplementation as Zn-Met at 40 of mg/kg of DM may improve antioxidant activity of dam and potentially increase passive immunity transfer in calves.

Sheep Methane Emission on Semiarid Native Pasture-Potential Impacts of Either Zinc Sulfate or Propylene Glycol as Mitigation Strategies

The aim of this study was to evaluate the effects of Zinc sulfate and propylene glycol (PG) on methane (CH₄) emission, nutrient intake, digestibility, and production in sheep grazing on a native Caatinga (Brazilian semi-arid savannah) pasture during the rainy season (from March to June 2014). Fifteen mixed Santa Inês sheep, all non-castrated males, with initial body weight of 19.8 ± 1.64 kg, and 4 ± 0.35 months of age, were distributed in a complete randomized design into three treatments: control (CT)-concentrate supplemented at 0.7% of body weight; CT + 300 mg of Zn/day; and CT + 2.5 mL of propylene glycol/kg LW^0.75/day. Measurements were done in four periods during the rainy season, with 28 days of interval between each measurement. CH₄ emission was measured using the SF₆ tracer gas technique. CH₄ emission per day was greater in PG than in CT and Zn (p < 0.05). However, no additive effect was observed on the intakes of organic matter (OM) and neutral detergent fiber (NDF), or on CH₄ emission expressed as a function of OM and NDF intakes (p > 0.05). Across the months of the trial, OM and NDF intakes were greater in March, while the greatest emission of CH₄ (g/day and g by g/OM intake) was observed in May (p < 0.05). Total CH₄ emission (kg) from March to June (112 days of evaluation) was greater in PG compared with CT and Zn (p < 0.05). Zinc and PG had no effect on total CH₄ emission when it was expressed per unit of body weight gain or carcass production (p > 0.05). The results of this study indicate that Zinc sulfate and propylene glycol have no beneficial effects in mitigating sheep CH₄ emission. The CH₄ emissions originated from sheep grazing native Caatinga pasture change throughout the rainy season due to fluctuations in availability and quality of pasture biomass. Moreover, the inclusion of zinc sulfate or propylene glycol did not improve animal feed intake, nutrient digestibility, and animal performance.

Influence of dietary zinc concentration and supplemental zinc source on nutrient digestibility, zinc absorption, and retention in sheep

The objective of this study was to assess whether supplemental Zn source or concentration would affect ruminant Zn retention and nutrient digestibility. Thirty-six weaned crossbred Polypay wethers, were sorted by BW to 3 periods and stagger started on a common diet (22 mg Zn/kg DM) for a 52-d depletion period. Day 52 BW was used to assign Zn treatments (3 lambs/treatment/period): no supplemental Zn (CON), or supplemental Zn (40 mg Zn/d) from Zn sulfate (ING; Zinc Nacional, Monterrey, SA, Mexico), Zn methionine (ORG; Zinpro 120; Zinpro, Eden Prairie, MN), or Zn hydroxychloride (HYD; IntelliBond Z; Micronutrients USA LLC, Indianapolis, IN). On day 53 (day 1 of Zn treatments), lambs were moved to metabolism crates for 10 d of adaptation and 5 d of total fecal and urine collection. Blood for plasma Zn analysis was collected on day 52 and day 68. Data were analyzed as a randomized complete design with fixed effects of treatment, period and the interaction, which was significant (P ≥ 0.19) for day 68 plasma Zn but was removed for all other variables. Contrast statements were used to separate treatment means: CON vs. ZINC (ING, ORG, HYD), ING vs. HYD, and ORG vs. HYD. Day 52 plasma Zn concentrations were similar when CON was compared with ZINC (P = 0.84), and when ING and ORG were compared with HYD (P ≥ 0.19). Dry matter and neutral detergent fiber digestibility were lesser in ORG compared with HYD (P = 0.05) and organic matter and acid detergent fiber digestibility tended (P ≤ 0.08) to be lesser in ORG compared with HYD. Intake and fecal excretion of Zn was lesser, while apparent absorption of Zn was greater, in CON compared with ZINC (P ≤ 0.001). Zinc retained as a percent of Zn intake was greater in CON compared with ZINC (P = 0.001). Zinc retained (mg/d) was similar in CON compared with ZINC (P = 0.58) and when ING or ORG were compared with HYD (P ≥ 0.83). There was a treatment × period interaction for day 68 plasma Zn where treatments did not differ for periods 1 and 3 but ORG lambs had increased plasma Zn in period 2 compared with other treatments (P = 0.02). Lambs receiving no supplemental Zn had increased apparent absorption, suggesting Zn absorption may be upregulated in these lambs. Similarities in Zn retention across treatments suggests Zn requirements of these lambs were met regardless of supplementation concentration or source. Nutrient digestibility was improved in HYD lambs compared with ORG, and further work is needed to clarify the influence of supplemental Zn source on nutrient digestion.

The influence of supplemental zinc and dietary fiber concentration on mineral retention of beef steers

The objective was to determine if zinc (Zn) retention improved with supplemental Zn above recommended concentrations with increasing dietary fiber concentration. Angus steers (n = 32; 309 ± 4.2 kg body weight [BW]) with GeneMax gain scores of 3, 4, or 5 were utilized in a 2 × 2 factorial arrangement (8 steers per treatment). Steers were stagger started (four blocks of eight steers) and stratified by BW within growing diets to one of two Zn strategies (ZNTRT), no supplemental Zn (analyzed 36 mg Zn/kg dry matter [DM]; CON) or supranutritional Zn (CON + 60 mg Zn/kg DM as ZnSO4 + 60 mg Zn/kg DM as Zn-amino acid complex; SUPZN). Dietary fiber strategies (FIBER) were formulated to target two fiber supplementation rates representing high fiber (HF; ~35% neutral detergent fiber [NDF]) or low fiber (LF; ~25% NDF). Within block, steers received HF for 60 d; then pens were randomly assigned to LF or HF for finishing. Steers fed LF were transitioned for 15 d; on day 75, steers were moved to metabolism crates and adapted for 10 d, followed by 5 d of total fecal and urine collection. Retention of Zn, Mn, Fe, Cu, and N were calculated. The model for analysis of metabolism data included the fixed effects of ZNTRT, FIBER, block, and the interaction of ZNTRT × FIBER, with the three-way interaction of ZNTRT × FIBER × block as random. Steer was the experimental unit (n = 8 per treatment combination). Zinc did not affect initial 60-d performance (P ≥ 0.62). DM and organic matter digestibility were lesser (P = 0.02) and N digestibility tended to be lesser (P = 0.07) in CON vs. SUPZN. Intake and digestibility of NDF and acid detergent fiber were greater (P ≤ 0.01) in HF vs. LF. Digestibility and retention of N as a percentage of intake were greater (P ≤ 0.04) whereas N retention as grams per day tended to be greater in HF vs. LF (P = 0.06). Apparent absorption of Zn tended to be greater (P = 0.06) in CON vs. SUPZN. A ZNTRT × FIBER effect was identified for Zn retention (milligrams per day; P = 0.01) where within SUPZN Zn retention was greater in HF vs. LF (P < 0.01). Apparent absorption and retention of Zn were greater (% of intake; P ≤ 0.02) in HF vs. LF. Apparent absorption of Cu, Fe, and Mn was unaffected by ZNTRT or FIBER (P ≥ 0.24). Increasing dietary Zn increased Zn retained regardless of changes in coefficient of absorption. In addition, dietary fiber content may impact trace mineral and N metabolism by steers, potentially due to increased release of these nutrients from feed as fiber digestibility increases. It appears dietary Zn concentrations and diet composition influence trace mineral absorption in beef steers.

Effects of supplemental zinc sulfate on growth performance, carcass characteristics, and antimicrobial resistance in feedlot heifers

Effects of supplemental Zn as Zn sulfate on feedlot performance, carcass traits, and antimicrobial resistance were evaluated using 480 crossbred heifers (BW = 385 kg ± 13.08) in a randomized complete block design. Heifers were blocked by BW and randomly assigned within block to diets with 0, 30, 60, or 90 mg supplemental Zn/kg DM. Heifers were housed in dirt-surfaced pens (20 animals per pen; 6 pens per treatment) equipped with fence-line feed bunks and automatic water fountains. Heifers were fed once daily to ensure ad libitum intake. Plasma was collected on day 0 from five randomly selected heifers per pen and repeated on days 63 and 115 to determine plasma Zn concentrations. Random samples of freshly voided feces were collected from the surface of each pen the day of harvest to determine antibiotic resistance. Heifers were transported on day 144 to a commercial abattoir where hot carcass weight (HCW) and incidence of liver abscesses were recorded at harvest and HCW, dressed yield, ribeye area, 12th rib fat, quality and yield grades were recorded after 36 h of refrigeration. Plasma Zn concentration increased (P = 0.02) linearly in response to increasing concentrations of dietary Zn. Final BW and ADG were unaffected by supplementation (P ≥ 0.29). Quantified levels of resistance to ceftriaxone and tetracycline among fecal Escherichia coli were not impacted (P > 0.05) by dietary zinc concentrations. Increasing Zn concentrations tended to decrease (linear effect, P = 0.07) DMI, resulting in a linear (P = 0.03) and tendency for quadratic (P = 0.12) improvement in feed efficiency with increasing Zn concentration. No differences were detected for HCW, dressed yield, ribeye area, 12th rib fat, percentages of carcasses grading Select or Choice, or yield grade (P > 0.53), but added Zn tended to affect percentage of carcasses that graded Prime, peaking at 60 mg/kg added Zn (quadratic effect, P = 0.07). In vitro fermentations were performed using ruminal fluid cultures containing 0, 30, 60, 90, 120, or 150 mg Zn/kg substrate DM to determine impact of Zn on gas production, VFA concentrations, and in vitro DM disappearance (IVDMD). There were no effects of Zn on in vitro gas production, IVDMD, or most VFA (P > 0.15), but isovalerate decreased linearly in response to added Zn (P = 0.05). Supplementing finishing heifers up to 60 mg Zn/kg diet DM improved feed efficiency compared to other treatments.

Effect of feeding micronutrient fertilized sorghum hay based diet on nutrient utilization and mineral balance in sheep

The present work was undertaken to study the effect of feeding micro-nutrient rich sorghum hay in the diet of sheep on nutrient intake and its utilization. Twelve adult Jalauni sheep (weighing 39.11±1.02 kg) were randomly divided into 2 groups of 6 animals each. The sheep of control group (G1) were fed on NPK fertilized chopped sorghum hay and crushed barley grain (300g/d) based ration, while the sheep of group G2 were offered NPK + 50% recommended dose of micronutrients (Zn, Mn and Cu 10, 5 and 2.5 kg/ha) + seed priming in 0.05% solution of ZnSO4 for 12 h + VAM inoculated sorghum hay along with barley grain (300g/d) for 30 days. Micro-nutrient (Cu, Zn and Mn) fertilization improved mineral content (ppm) in sorghum hay for Cu (7.47 vs 9.22), Zn (22.69 vs 27.48) and Mn (73.56 vs 102.01). The effective intake of minerals was Cu, 8.71and 10.06, Zn, 26.23 and 30.18; Mn, 62.59 and 86.05 ppm in G1and G2, respectively. The additional mineral supplementation through micronutrient rich sorghum hay had no significant effect on dry matter intake. Similarly, the intakes of digestible crude protein, metabolizable energy and digestibility of DM, CP, NDF, ADF, were also comparable among the groups. However, micro-nutrient (Cu, Zn and Mn) supplementation through fodder sorghum improved the mineral retention (Cu 2.84 vs 3.72 mg/d, Zn 11.72 vs 15.46 mg/d and Mn 26.19 vs 40.28 mg/d) without affecting significantly the absorption coefficient in adult sheep. The apparent absorption and retention of N was positive and comparable between thegroups. Nutrient content (%) in terms of DCP and TDN in both type diets fed to sheep were also similar. Thus, it  can be concluded that micro-nutrient (Cu, Zn and Mn) application to fodder sorghum improved the mineral content in the fodder, and feeding of micronutrient fertilized sorghum hay based diet improve the intake and retention of micro-minerals significantly without affecting nutrient intake and nutrient utilization in adult Jalauni sheep.

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.

Efeito da suplementação com sulfato de zinco ou propilenoglicol em ovinos em uma pastagem nativa da Caatinga no período chuvoso: desempenho, características da carcaça e da carne

RESUMO Objetivou-se avaliar os efeitos do zinco ou do propilenoglicol sobre o desempenho e nas características da carcaça e da carne de ovinos sob pastejo em pastagem nativa da Caatinga. Utilizaram-se 24 ovinos, mestiços Santa Inês, machos, não castrados, peso inicial de 19,3±2,52kg, com quatro meses de idade, oito repetições por tratamento, distribuídos em um delineamento inteiramente ao acaso. Os tratamentos foram: sem aditivo, controle (CT), adição de sulfato de zinco (ZnSO4.7H2O) (Zn) para fornecimento de 300mg de Zn dia-1 via sal mineral, e propilenoglicol (PG), 2,5mL kgPC0,75-1 animal-1 dia-1 misturado no concentrado. Os animais foram suplementados com concentrado constituído de milho (54,0%), farelo de soja (45,1%) e calcário (0,911%) em 0,7% do PC médio de cada tratamento. O ensaio foi conduzido durante quatro meses (março a junho/2014). Avaliaram-se o desempenho e, após o abate dos animais, as características de carcaça e os componentes não carcaça, os parâmetros físico-químicos e organolépticos na carne. O Zn e o propilenoglicol não afetaram o desempenho e os parâmetros da carcaça em termos absoluto e relativo, bem como os pesos dos cortes e seus rendimentos (P>0,05). Não houve efeito dos aditivos nas características organolépticas e nos aspectos físico-químicos da carne (P>0,05), exceto cinzas (P<0,05). O zinco e o propilenoglicol não melhoram o desempenho e as características da carcaça de animais terminados em pastagem nativa da Caatinga. O baixo suprimento energético devido à má qualidade do pasto entre os meses de abril a junho contribui para a ineficiência no aproveitamento dos constituintes proteicos, implicando menor consumo e consequente diminuição do desempenho.

The effect of trace mineral source and concentration on ruminal digestion and mineral solubility

The objective of this experiment was to compare the effect of sources of sulfate trace mineral (STM) and hydroxy trace mineral (HTM) at different inclusions on digestibility of dry matter (DM) and neutral detergent fiber and solubility of Cu, Mn, and Zn in the rumen and abomasum of cattle. Five ruminally cannulated steers were used in a 5×5 Latin square design and individually fed a corn silage-based diet on an ad libitum basis. The 5 dietary treatments were as follows: control: no supplemental Cu, Mn, or Zn, analyzed to contain 7.4mg of Cu, 30.8mg of Mn, and 32.1mg of Zn per kilogram of diet DM (CON); low sulfate: 5mg of Cu/kg of DM supplemented from CuSO4, 15mg of Mn/kg of DM from MnSO4, and 30mg of Zn/kg of DM from ZnSO4; low HTM: 5mg of Cu/kg of DM supplemented from basic copper chloride (IntelliBond C; Micronutrients Inc., Indianapolis, IN), 15mg of Mn/kg of DM from manganese hydroxychloride (IntelliBond M; Micronutrients Inc.), and 30mg of Zn/kg of DM from zinc hydroxychloride (IntelliBond Z; Micronutrients Inc.); high sulfate: 25mg of Cu/kg of DM supplemented from CuSO4, 60mg of Mn/kg of DM from MnSO4, and 120mg of Zn/kg of DM from ZnSO4; and high HTM: 25mg of Cu/kg of DM supplemented from basic copper chloride, 60mg of Mn/kg of DM from manganese hydroxychloride, and 120mg of Zn/kg of DM from zinc hydroxychloride. Periods lasted for 12d, with 10d of diet adaptation. Dacron bags containing the CON total mixed ration were inserted on d 11 at 0h and were removed at 6, 12, 24, and 36h after insertion. Dry matter and neutral detergent fiber disappearances and rumen and simulated abomasal trace mineral solubilities were evaluated. Dietary treatment did not affect DM intake. Dry matter disappearance was lesser in supplemental TM treatments and greater in CON than the STM treatments, although the CON and HTM treatments did not differ. Neutral detergent fiber disappearance was not affected by treatment. Ruminally soluble Cu and Mn concentrations were least in CON and were lesser in HTM-containing treatments compared with STM treatments. However, in the abomasum, solubilities of Cu and Mn were similar across trace mineral sources. Ruminal and simulated abomasal soluble Zn was greater in the HTM treatments than in CON and STM, driven by the greater solubility of the high HTM treatment. Under the conditions of this study, supplementing trace minerals as STM decreased DM digestibility, whereas HTM did not affect DM digestibility. Additionally, Cu and Mn from HTM sources were relatively insoluble in the rumen but had similar solubility as STM at the pH found in the abomasum, suggesting that these minerals should be available for absorption in the intestine.

Effects of peroral supplementation of different forms of zinc on the ruminal mucosa of goat kids – a morphometric study

The aim of the study was to identify the effect of supplementation of various forms of zinc on the ruminal mucosa and dimensions of ruminal papillae in 6-month-old goat kids. The experimental period lasted from weaning to slaughter (4 months). All 20 kids divided into four groups of five animals, were fed with the same feeding dose, which was different only in the quantity and form of zinc. Control group was without additional zinc supplementation (group A), the other groups were supplemented with zinc in the form of ZnO (group B), zinc in the form of chelate (group C) and zinc in the form of lactate (group D). Samples for histopathological and morphometric examination were collected after the slaughter of all animals from the bottom of saccus ruminis ventralis everytime from the same place. Significant differences were reported within the comparison of the length of ruminal papillae between groups B and C (P = 0.026) and B and D (P = 0.040), within the comparison of the width of ruminal papillae between groups A and D (P = 0.020) and within the comparison of the intensity of keratinisation of the mucosa of ruminal papillae between groups A and B (P = 0.034), A and C (P = 0.038) and A and D (P = 0.001). Histopathological and morphometric examination of ruminal mucosa indicated that the ruminal papillae of kids supplemented with zinc in the form of ZnO (group B) were better developed compared to the other groups. This result indicates better utilisation of the supplemented zinc in the form of ZnO.

In vitro gas production and dry matter degradability of diets consumed by goats with or without copper and zinc supplementation

An in vitro gas production technique was used to evaluate the effects of copper and zinc supplementation on the amount and rate of gas production, dry matter degradability (IVDMD), utilization of metabolizable energy (ME), and ruminal fermentation patterns using rumen fluid from four Boer male goats as inoculum. The goats were fed twice daily at 07:00 and 19:00 h a total mixed ration containing 10.3 and 22.5 mg/kg DM of Cu and Zn, respectively. This diet was incubated in vitro for 96 h with four treatments being: control, Cu (21.7), Zn (5.6), and Cu-Zn (21.7 and 5.6) which was provided as a mineral premix. Data were analyzed as a completely randomized design. Rates of gas production (RGP) at 4 (RGP(4h)) and 6 h (RGP(6h)) and gas production (GP) at 24 (GP(24h)) and 48 h (GP(48h)) differed (p < 0.01) among treatments. An addition of Cu increased the RGP(4h), RGP(6h), GP(24h), and GP(48h) (p < 0.0001). The Cu treatment had the highest IVDMD and control the lowest (p < 0.05), and the Cu treatment was the highest values of ME and SCFA. The addition of Cu to the in vitro ruminal fermentation increased gas production and efficiency of energy use.

Silage supports sulfate reduction in the treatment of metals- and sulfate-containing waste waters

Silage was used as source of carbon and electrons for enrichment of silage-degrading and sulfate reducing bacteria (SRB) from boreal, acidic, metals-containing peat-bog samples and to support their use in batch and semi-batch systems in treatment of synthetic waste water. Sulfidogenic silage utilization resulted in a rapid decrease in lactate concentrations; concentrations of acetate, butyrate and propionate increased concomitantly. Synthetic waste water consisting of Mn, Mg and Fe (II) ions inhibited sulfate reduction at concentrations of 6 g/l, 8 g/l and 1 g/l respectively. During treatment, Mn and Mg ions remained in solution while Fe ions partially precipitated. Up to 87 mg sulfate was reduced per gram of silage. Sulfate reduction rates of 34, 22 and 6 mg/l/day were obtained at temperatures of 30, 20 and 9 °C respectively. In semi-batch reactors operated at low pH, the iron precipitation capacity was controlled by sulfate reduction rates and by partial loss of hydrogen sulfide to the gas phase. Passive reactor systems should, therefore, be operated at neutral pH. Metals tolerant, silage-fermenting (predominantly species belonging to genus Clostridium) and sulfate reducing bacteria (including a species similar to the psychrotolerant Desulfovibrio arcticus) were obtained from the peat bog samples. This work demonstrates that silage supports sulfate reduction and can be used as a low cost carbon and electron source for SRB in treatment of metals-containing waste water.