Evaluating the NRC levels of Cu, Fe, Mn, and Zn using organic and inorganic mineral sources for grower-finisher swine

Dietary replacement of inorganic trace minerals with lower levels of organic trace minerals leads to enhanced antioxidant capacity, nutrient digestibility, and reduced fecal mineral excretion in growing-finishing pigs

Introduction

More effective and environment-friendly organic trace minerals have great potential to replace the inorganic elements in the diets of livestock. This study aimed to investigate the effects of dietary replacement of 100% inorganic trace minerals (ITMs) with 30-60% organic trace minerals (OTMs) on the performance, meat quality, antioxidant capacity, nutrient digestibility, and fecal mineral excretion and to assess whether low-dose OTMs could replace whole ITMs in growing-finishing pigs' diets.

Methods

A total of 72 growing-finishing pigs (Duroc × Landrace × Yorkshire) with an initial average body weight of 74.25 ± 0.41 kg were selected and divided into four groups with six replicates per group and three pigs per replicate. The pigs were fed either a corn-soybean meal basal diet containing commercial levels of 100% ITMs or a basal diet with 30, 45, or 60% amino acid-chelated trace minerals instead of 100% ITMs, respectively. The trial ended when the pigs' weight reached ~110 kg.

Results

The results showed that replacing 100% ITMs with 30-60% OTMs had no adverse effect on average daily gain, average daily feed intake, feed/gain, carcass traits, or meat quality (P > 0.05) but significantly increased serum transferrin and calcium contents (P < 0.05). Meanwhile, replacing 100% ITMs with OTMs tended to increase serum T-SOD activity (0.05 ≤ P < 0.1), and 30% OTMs significantly increased muscle Mn-SOD activity (P < 0.05). Moreover, replacing 100% ITMs with OTMs tended to increase the apparent digestibility of energy, dry matter, and crude protein (0.05 ≤ P < 0.1) while significantly reducing the contents of copper, zinc, and manganese in feces (P < 0.05).

Discussion

In conclusion, dietary supplementation with 30-60% OTMs has the potential to replace 100% ITMs for improving antioxidant capacity and nutrient digestibility and for reducing fecal mineral excretion without compromising the performance of growing-finishing pigs.

Too Much of a Good Thing: Rethinking Feed Formulation and Feeding Practices for Zinc in Swine Diets to Achieve One Health and Environmental Sustainability

The objectives of this review were to summarize current knowledge of Zn in swine nutrition, environmental concerns, potential contribution to antimicrobial resistance, and explore the use of alternative feeding strategies to reduce Zn excretion in manure while capturing improvements in productivity. Zinc is a required nutrient for pigs but is commonly supplemented at concentrations that greatly exceed estimated requirements. Feeding pharmacological concentrations of Zn from ZnO to pigs for 1 to 2 weeks post-weaning reduces post-weaning diarrhea and improves growth performance. Feeding elevated dietary levels of Zn to sows during the last 30 days of gestation can reduce the incidence of low-birth-weight pigs and pre-weaning mortality. Most of the dietary Zn consumed by pigs is not retained in the body and is subsequently excreted in manure, which led several countries to impose regulations restricting dietary Zn concentrations to reduce environmental impacts. Although restricting Zn supplementation in swine diets is a reasonable approach for reducing environmental pollution, it does not allow capturing health and productivity benefits from strategic use of elevated dietary Zn concentrations. Therefore, we propose feeding strategies that allow strategic use of high dietary concentrations of Zn while also reducing Zn excretion in manure compared with current feeding practices.

Effects of the methionine hydroxyl analog chelated microminerals on growth performance, antioxidant status, and immune response of growing-finishing pigs

This study aimed to investigate the effects of methionine hydroxyl analog chelated microminerals (MHA-M) replacing inorganic microminerals (ITMs) on the growth performance, fecal microminerals concentrations, immune function, and antioxidant status in growing-finishing pigs; 253 pigs (average 33.68 kg body weight) were randomly assigned to six treatments with six replicates each treatment: (1) ITM: a basal diet with Cu, Fe, Mn, and Zn from sulfates providing 20, 100, 40, and 60 mg/kg; (2-6): 1/5MHA-M, 2/5MHA-M, 3/5MHA-M, 4/5MHA-M, and MHA-M was replaced with 20%, 40%, 60%, 80%, and 100% MHA-M. Results showed that the average daily gain (ADG) in the 1/5MHA-M and 2/5MHA-M was greater than other groups in the whole period. Fecal Cu, Fe, Mn, and Zn concentrations had decreased as the intake of trace minerals decreases. The ITM group decreased the fecal Zn concentration on Days 35, 70, and 91, and Fe concentration on Day 70, and increased the Mn concentration on Day 70 compared with MHA-M group. Pigs fed 1/5MHA-M, 2/5MHA-M, and MHA-M had a higher immune function and antioxidant status in serum compared with ITM, 3/5MHA-M, and 4/5MHA-M on Day 35. In conclusion, treatment with 1/5MHA-M and 2/5MHA-M could reduce the excretion of fecal microminerals and improve the immune function and antioxidant capacity compared with the ITM group.

Evaluating the Influence of Different Recommended Dietary Levels of Cu and Zn on Finishing Pigs

This study was conducted to evaluate the effects of dietary supplementation of different recommended levels of Cu and Zn on antioxidant capacity, tissue mineral status, minerals excretion, meat quality, digestive enzyme activity, and metal transporters in finishing pigs. A total of 120 pigs (with an average initial body weight (BW) of 70.0 ± 2.1 kg) were randomly divided into four treatments: (1) basal diet without added Cu or Zn (control), (2) basal diet+35 mg cupreous N-carbamylglutamate chelate (NCG-Cu) +150 mg zinc-methionine chelate (Zn-Met) (AC), (3) basal diet + 3.0 mg of NCG-Cu + 43 mg Zn-Met (CN), and (4) basal diet + 3.5 mg NCG-Cu + 50 mg Zn-Met (NRC100). Pig growth performance was not affected by the level of Cu or Zn. Among the four treatments, the AC treatment had the highest concentration (P < 0.05) of glutathione peroxidase (GSH-Px). Pigs fed the AC diet had the highest (P < 0.05) liver Zn, fecal Cu, and fecal Zn among the four treatments. The protein levels of trypsin and aminopeptidase N (APN) in the intestinal mucosa showed their highest levels (P < 0.05) in the NRC100 and AC treatments. The mRNA levels of trypsinogen and APN were significantly up-regulated (P < 0.05) in the AC, CN, and NRC100 treatments compared with the control. The mRNA levels for the Zn transporter genes SLC30A1 (ZnT1) and SLC30A2 (ZnT2) were significantly up-regulated (P < 0.05) in the AC treatment, and the mRNA levels for SLC39A4 (ZIP4) and metallothionein 1 (MT) in the AC, CN, and NRC100 treatments were significantly up-regulated (P < 0.05) compared with the control. Meat quality were not affected (P > 0.05) by the different recommended levels of Cu and Zn. These results indicated that the supplemental Cu and Zn levels routinely used in AC diets in Chinese commercial feed enterprises should be reduced.

Effect of different levels of organic zinc supplementation on pork quality

This study investigated the effect of two supplementation levels of zinc glycinate (ZnGly) on performance, carcass characteristics, and meat quality of growing-finishing pigs. Thirty pigs (bodyweight: 61 ± 4.0 kg) were assigned to three treatments and fed ad libitum for 56 days a diet supplemented with 0 (control), 45 (Zn45), or 100 mg/kg (Zn100) of ZnGly. The highest ZnGly supplementation lowered the average daily gain (P = 0.031); while, cold carcass weight did not differ between treatments. Both ZnGly levels reduced carcass chill loss (P < 0.001). Micromineral content, color stability, and fatty acid profile of meat were not altered by ZnGly. Superoxide dismutase activity was lowered by Zn45 compared to control (P = 0.007); while, catalase activity was enhanced by Zn100 (P = 0.003). Although ZnGly supplementation did not influence lipid oxidation in raw meat and in meat homogenates incubated with pro-oxidant catalysts, Zn45 limited lipid oxidation in cooked meat (P = 0.037). Our results demonstrated that supplementing pigs with 45 mg/kg of ZnGly could improve the oxidative stability of pork subjected to strong pro-oxidant conditions, but this effect needs to be further elucidated.

Effects of two zinc supplementation levels and two zinc and copper sources with different solubility characteristics on the growth performance, carcass characteristics and digestibility of growing-finishing pigs

The present study was conducted to evaluate the effect of two Zn supplemented levels and two Zn and Cu sources (sulphate and hydroxychloride) on growing-finishing pigs. An in vitro study and an in vivo study were conducted. In the in vitro study, Zn solubility from each source at different Zn supplementation levels was evaluated, as well as the phytic phosphorus (PP) solubility derived from the interaction or not with phytic acid at similar conditions to those found in digestive tract. The most critical interaction of Zn with phytic acid was at pH 6.5 and with Zn sulphate, resulting in the reduction in PP solubility. In the in vivo experiment, a total of 444 pigs ([Duroc × Landrace]×Pietrain; initial BW: 18.7 ± 0.20 kg) were allotted to 36 pens in a randomized complete block design (2 × 2) factorial arrangement with two Zn and Cu sources and two Zn supplemental levels (20 and 80 mg/kg). The Cu supplementation was fixed at 15 mg/kg for all diets. There was no effect of the interaction between mineral source × Zn level or Zn level on growth performance or carcass characteristics (p > .10). Apparent total digestibility of Zn and Cu along with carcass yield was higher for pigs fed hydroxychloride than pigs fed the sulphate counterparts (p < .05). Feeding low levels of Zn decreased Zn (45.5%; p < .0001) and Cu(18.5%; p = .018) faecal excretion. In conclusion, under commercial conditions, feeding growing-finishing pigs with Zn levels below those established by the European Union regulation did not affect growth performance and carcass characteristics. Reducing dietary mineral (Zn and Cu) diet content resulted in a lower faecal mineral excretion. Pigs fed sulphate minerals had an improved performance during grower period, while pigs fed hydroxychloride minerals showed an improved performance during finishing period and a greater carcass yield and mineral digestibility than those fed sulphates.

The strategies for the supplementation of vitamins and trace minerals in pig production: surveying major producers in China

Objective

Adequate vitamin and trace mineral intake for pigs are important to achieve satisfactory growth performance. There are no data available on the vitamin and trace mineral intake across pig producers in China. The purpose of this study was to investigate and describe the amount of vitamin and trace minerals used in Chinese pig diets.

Methods

A 1-year survey of supplemented vitamin and trace minerals in pig diets was organized in China. A total of 69 producers were invited for the survey, which represents approximately 90% of the pig herd in China. Data were compiled by bodyweight stages to determine descriptive statistics. Nutrients were evaluated for vitamin A, vitamin D, vitamin E, vitamin K, thiamine, riboflavin, vitamin B₆, vitamin B₁₂, pantothenic acid, niacin, folic acid, biotin, choline, copper, iron, manganese, zinc, selenium, and iodine. Data were statistically analyzed by functions in Excel.

Results

The results indicated variation for supplemented vitamin (vitamin A, vitamin D, vitamin E, vitamin K, vitamin B₁₂, pantothenic acid, niacin, and choline) and trace minerals (copper, manganese, zinc, and iodine) in pig diets, but most vitamins and trace minerals were included at concentrations far above the total dietary requirement estimates reported by the National Research Council and the China’s Feeding Standard of Swine.

Conclusion

The levels of vitamin and trace mineral used in China’s pig industry vary widely. Adding a high concentration for vitamin and trace mineral appears to be common practice in pig diets. This investigation provides a reference for supplementation rates of the vitamins and trace minerals in the China’s pig industry.

Physiological parameter values for physiologically based pharmacokinetic models in food-producing animals. Part I: Cattle and swine

Physiologically based pharmacokinetic (PBPK) models for chemicals in food animals are a useful tool in estimating chemical tissue residues and withdrawal intervals. Physiological parameters such as organ weights and blood flows are an important component of a PBPK model. The objective of this study was to compile PBPK‐related physiological parameter data in food animals, including cattle and swine. Comprehensive literature searches were performed in PubMed, Google Scholar, ScienceDirect, and ProQuest. Relevant literature was reviewed and tables of relevant parameters such as relative organ weights (% of body weight) and relative blood flows (% of cardiac output) were compiled for different production classes of cattle and swine. The mean and standard deviation of each parameter were calculated to characterize their variability and uncertainty and to allow investigators to conduct population PBPK analysis via Monte Carlo simulations. Regression equations using weight or age were created for parameters having sufficient data. These compiled data provide a comprehensive physiological parameter database for developing PBPK models of chemicals in cattle and swine to support animal‐derived food safety assessment. This work also provides a basis to compile data in other food animal species, including goats, sheep, chickens, and turkeys.

Effects of supplementing organic microminerals and methionine with or without limiting growth during the rearing phase of replacement gilts on lameness, growth, and body composition

Previous research suggested that lameness in growing pigs could be reduced using feeding strategies, such as limiting growth rate and supplementing trace minerals (TM) and (or) methionine (Met). The present study evaluates effects of 1) TM and Met and 2) limiting total lysine (Lys) during the rearing phase (90 d) of gilts (as a means to limit growth rate) on lameness, performance, and sow claw health and productivity (to first parity). Gilts (n = 240; 58.0 ± 11.1 kg body weight [BW]) were blocked, distributed into pens of 10 gilts, and pens were allocated to a 2 × 2 factorial arrangement. Factors were: 1) control or TM plus Met, which provided additional 10, 20, and 50 mg/kg of chelated copper, manganese, and zinc, respectively (0.1%, Aplomotec Plus, Tecnología & Vitaminas, S.L.; Alforja, Spain), and a 1.01 Met:Lys ratio and 2) standard Lys was formulated to meet growth requirements or low Lys to 19% below growth requirements. Feeding was provided through two phases, first between 119 and 163 d of age (phase I) and the second between 163 and 209 d of age (phase II). Diets had 2.43 and 2.31 Mcal net energy/kg for phases I and II, respectively, and were offered ad libitum. Low Lys did not affect feed intake but rather reduced average daily gain (ADG) by 6.35% and the final BW by 3.80% compared with standard Lys (P < 0.001). Low Lys reduced ADG (P < 0.001) and gain:feed (P = 0.012) during phase I but not during phase II. Lameness prevalence was 7.92% during rearing and increased with time (P < 0.001). Final BW (151 kg) and ADG (989 g) were similar (P > 0.05) whether gilts displayed lameness or not. Lameness was low in severity and not affected by dietary factors. However, TM- plus Met-fed gilts were 19.2 kg heavier (P = 0.016) than were control at lameness detection. On the sow farm, there was no evidence for differences in lameness or claw lesions among previous dietary treatments. In conclusion, lameness prevalence during the rearing phase was similar, independent of TM plus Met supplement, low Lys, or the interaction. Insufficient reduction of ADG and low severity in lameness may have limited the potential of dietary treatments. Moreover, a greater deficiency of Lys would be needed to achieve the degree of growth reduction previously reported to lessen lameness through feed restriction.

Effects of increasing dietary zinc on growth performance and carcass characteristics of pigs raised under commercial conditions. Transl Anim Sci 2019;3:731-736. [PMID: 32704840 PMCID: PMC7200868 DOI: 10.1093/tas/txz054]

A total of 2,430 pigs (PIC 337 × 1050; Hendersonville, TN; initially 30.1 kg) were used in a 113-d growth trial to determine the effects of increasing dietary Zn on growth performance and carcass characteristics of finishing pigs raised under commercial conditions. Pens of pigs were assigned to be fed one of five dietary treatments in a randomized complete block design. Treatments consisted of 50, 87.5, 125, 162.5, or 200 mg/kg added Zn from Zn hydroxychloride (IntelliBond Z, Micronutrients, Indianapolis, IN). Two identical barns were used for a total of 18 pens per treatment with 27 pigs per pen. Experimental diets were fed in five phases and contained a vitamin-trace mineral premix without added Zn. Pens of pigs were weighed approximately every 2 wk to calculate average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F). At the end of the experimental period, pigs were tattooed with a pen identification number and transported to a packing plant to measure hot carcass weight (HCW), backfat, loin depth, and calculated lean percentage. Data were analyzed block nested within barn as a random effect and pen as the experimental unit. From days 0 to 42, pigs fed diets with increasing added Zn had lower (linear, P = 0.043) ADFI and a tendency (P = 0.092) for lower ADG. From days 42 to 113, increasing added Zn resulted in a quadratic response (P = 0.042) for ADFI and a tendency (linear, P = 0.056) for improved G:F. Overall (days 0 to 113), there were tendencies for quadratic responses for ADFI (P = 0.073) and G:F (P = 0.059), with the greatest G:F observed when 125 mg/kg of Zn was fed. Increasing added Zn resulted in a linear increase (P < 0.001) in daily Zn intake. There were no differences (P > 0.10) in overall ADG, final body weight, HCW, backfat, loin depth, lean percentage, mortality, and removal rate. In conclusion, there were no improvements in ADG when feeding beyond 50 mg/kg added Zn; however, providing 125 mg/kg added Zn resulted in the greatest G:F.

Effects of zinc source and level on growth performance and carcass characteristics of finishing pigs. Transl Anim Sci 2019;3:742-748. [PMID: 32704842 PMCID: PMC7200915 DOI: 10.1093/tas/txz071]

An experiment was conducted to determine the effects of added Zn source and level on growth performance and carcass characteristics of finishing pigs. A total of 1,980 pigs divided into 2 groups [group 1: 1,008 pigs, TR4 × (Fast Large White × PIC L02) and group 2: 972 pigs, PIC 337 × 1,050], initially 33.3 kg, were used in a 103- or 114-d growth trial in groups 1 and 2, respectively. Treatments were arranged in a 2 × 3 factorial with 2 sources of added Zn, Zn hydroxychloride (ZnHyd; IntelliBond Z, Micronutrients, Indianapolis, IN) or Zn sulfate (ZnSO4), and 3 levels of added Zn (50, 100, or 150 mg/kg). Diets contained a vitamin-trace mineral premix without added Zn and provided 76 and 162 mg/kg Fe and Cu, respectively. All diets contained 750 FTU/kg phytase. There was a total of 14 replicates per treatment. Pens of pigs were weighed approximately every 2 wk to determine average daily gain (ADG), average daily feed intake, and gain-to-feed ratio. At the end of the experiment, pigs were transported to a packing plant to determine hot carcass weight (HCW), backfat depth, loin depth, and lean percentage. Overall, there was no evidence (P > 0.10) for interactive effects of added Zn source and level for growth performance and carcass characteristics. Pigs fed diets with increasing added Zn had a tendency (P = 0.093) for a quadratic response in ADG, with the greatest ADG observed at 100 mg/kg added Zn. There was a linear improvement (P = 0.010) in carcass yield and a quadratic response (P = 0.045) in HCW, with pigs fed 100 mg/kg added Zn having the highest HCW. Pigs fed diets with ZnHyd had improved (P = 0.017) carcass yield and a tendency (P = 0.058) for greater HCW compared with pigs fed ZnSO4. In summary, under the commercial conditions of the study and with diets containing 750 FTU/kg phytase, there were relatively small improvements in ADG of growing-finishing pigs fed added Zn beyond 50 mg/kg. Providing higher levels of added Zn improved carcass characteristics. Zinc source did not influence growth performance, but ZnHyd improved carcass characteristics compared with ZnSO4.

Effects of supplementing organic microminerals and methionine during the rearing phase of replacement gilts on lameness, growth, and body composition

Lameness is a primary reason for culling and mortality within a sow herd. This study evaluated the impact of feeding organic trace minerals and methionine (Met) to growing gilts (134 d) on lameness, performance, body composition and claw health (to first parity), productivity (to second parity), and reproductive performance through 2 parities. Young gilts (28.8 ± 8.8 kg of body weight [BW], n = 360) were BW blocked (10 gilts/pen) and randomly allotted to 1 of 4 dietary treatments: control (CON, basal diet); CON plus organic minerals (MIN, at 10, 20, and 50 mg/kg of Cu, Mn, and Zn, respectively; Aplomotec Plus, Tecnología & Vitaminas, S.L, Alforja, Spain); additional Met (MET, at 102% Met: Lys); and MET plus MIN (MM). Feed was provided ad libitum. Lameness, BW, and body composition were measured 7 times during rearing, at gilt service, day 109 of gestation, and first weaning. Gilts fed the MM diet had lower average daily feed intake (5.1%) and final BW (2.1%) than CON gilts (P < 0.05), whereas MIN and MET were intermediate and not different from each other. Similarly, final backfat (BF) was greatest in CON (P < 0.05), whereas CON and MIN increased final loin depth compared with MM (P < 0.05) with MET not being different. During rearing, 7.7% of all gilts presented lameness, which appeared between 106.8 and 129.7 kg BW confidence interval. Gilts that had been or were lame had reduced BW and average daily gain compared with never lame gilts (P < 0.05). Lameness during rearing was highest (P < 0.01) in gilts fed CON diet (14.8%), with no differences amongst MIN (2.0%), MET (5.3%), or MM (6.5%). In the sow herd, 21% of sows showed lameness and 24% of those were associated with claw lesions. At weaning, gilts fed CON diet had highest (P < 0.01) prevalence of lameness (20.8%) with no differences amongst MIN (6.5%), MET (11.1%), or MM (7.6%). Over the first 2 parities, 27.3% of gilts were culled. On farm, lameness was associated with 0.7 more stillborn piglets (P < 0.10), 1 mm more BF loss in first lactation (P < 0.05), and increased weaning-to-estrus by 3 d (P < 0.05). In conclusion, lameness during rearing was decreased by supplementing organic trace minerals, methionine, and their combination, which also reduced lameness during lactation.

Effect of dietary copper level on the gut microbiota and its correlation with serum inflammatory cytokines in Sprague-Dawley rats

In China's swine industry, copper is generally supplemented above the National Research Council (NRC) requirement (2012) because of its antimicrobial properties and the potential for growth promotion. Yet few are concerned about whether this excess supplementation is necessary. In this study, the 16S rRNA pyrosequencing was designed and used to investigate the effect of dietary copper level on the diversity of the fecal microbial community and the correlation of copper level with the serum level of inflammatory cytokines in Sprague-Dawley rat models. The results showed that the diet containing a high level of Cu (120 and 240 mg/kg) changed the microbial richness and diversity of rat feces associated with the increased copper content in the rat ileac and colonic digesta. Furthermore, a Pearson's correlation analysis indicated that an accumulation of unabsorbed copper in the chyme was correlated with the microbial composition of the rat feces, which was linked with TNF-α in serum. The results suggest that dietary copper level may have a direct impact on circulating inflammatory cytokines in the serum, perhaps inducing an inflammatory response by altering the microbial composition of rat feces. Serum TNF-α could be the chief responder to excessive copper exposure.

Effects of Replacing of Inorganic Trace Minerals by Organically Bound Trace Minerals on Growth Performance, Tissue Mineral Status, and Fecal Mineral Excretion in Commercial Grower-Finisher Pigs

A total of 180 crossbred pigs (Duroc × Landrace × Large White; BW = 47.1 ± 4.8 kg) were used to investigate the effects of totally replacing inorganic trace minerals (ITMs) by organically bound trace minerals (OTMs) on growth performance, tissue mineral status, liver antioxidant enzyme activities, and fecal mineral excretion in grower-finisher pigs. A randomized complete block design with three treatments and six replicates (n = 10 pigs per pen) was used in this 69-day, 2-phase feeding trial. Experimental treatments were as follows: (1) a basal diet without trace mineral supplementation, (2) basal + ITMs (Fe, Mn, and Zn from sulfates, Cu oxychloride, and sodium selenite providing commercially recommended levels in China at 125, 22.5, 117.5, 30, and 0.3 mg/kg, respectively), and 3) basal + OTMs (Fe, Mn, Zn, and Cu from Bioplex and Se as Sel-Plex (Alltech Inc., Nicholasville, KY) providing levels identical to ITMs). No significant differences (P > 0.05) were observed in ADG, ADFI, or G:F among the treatments during the entire grower-finisher period. Supplementation with minerals, regardless of source, increased (P < 0.05) the Fe, Cu, and Se levels in the plasma; Fe and Zn levels in the liver; and Se levels in heart. Furthermore, compared with ITM group, the concentration of Zn and Se in the liver and heart, and Se in plasma and longissimus muscle were greater (P < 0.05) in OTM group. Hepatic Cu/Zn-SOD and ALP activities were increased (P < 0.05) when either ITMs or OTMs were supplemented. Pigs supplemented with OTMs displayed greater activities of Cu/Zn-SOD, ALP, and GSH-Px in the liver compared to pigs supplemented with ITMs. Dietary mineral supplementation to pig diets greatly increased (P < 0.05) fecal mineral (Fe, Mn, Zn, Cu, and Se) excretion in both grower and finisher phases. Fecal concentrations of Zn, Cu, and Se excretion were lower (P < 0.05) with OTMs supplementation than that in pigs fed diets containing ITMs. These results indicate that use of organic trace minerals, as well as no trace mineral supplementation, did not influence pig growth performance. Totally replacing ITMs by equivalent levels of OTMs could improve hepatic Cu/Zn-SOD, ALP, and GSH-Px activities and reduce fecal Mn, Cu, and Se excretion for grower-finisher pigs when supplemented at commercially recommended levels.

Evaluating dietary adjustment and collection times for total tract digestibility of Ca, P, and the essential microminerals with grower swine

An experiment was conducted to determine 1) the length of time necessary for grower pigs to adjust to a new diet and 2) the consistency in excretion of urine and feces in 4 consecutive 5-d collection periods. The total tract excretion and digestibility values for Ca, P, and the essential microminerals were evaluated. The experiment was conducted in 6 replicates as a randomized complete block design. Pigs were fed a pretest diet from 20 to 40 kg BW that met the requirements. At 40 kg, 12 barrows were allotted to stainless-steel metabolism crates, where they continued being fed the pretest diet for a 7-d period for adjustment purposes. Treatment diets were then fed for the following 20-d period in four 5-d intervals. Treatment diets were a corn-soybean meal mixture and contained either 1) reduced Ca and P levels and no added microminerals (LOW) or 2) a diet with elevated Ca and P levels and supplemental microminerals that exceeded the pig's requirements (HIGH). The study collected urine and feces. Markers were added to the ration at the start of each period to distinguish between test intervals. Feces and urine were collected daily, frozen, and composited for each period. Analysis of diets and excrement was conducted using inductively coupled plasma mass spectrometry technology. In all cases, the excreted minerals and digestibility values were greater ( < 0.01) for the macrominerals when the HIGH diet was fed, whereas the digestibility values for the microminerals were often lower when the HIGH diet was fed. The macrominerals Ca and P both had consistent urine and fecal values for each of the final 3 collection periods within diet. The micromineral values were generally consistent for each 5-d collection period but varied between periods for several microminerals. These results indicate that a 5-d adjustment period was adequate for pigs to adjust to the treatment diets. A 5-d collection period was adequate for Ca and P, but the micromineral excretion and digestibility values were more variable, and a collection period of 10 d might be warranted. The results also indicated that the innate microminerals had a higher digestibility and bioavailability than thought previously and their digestibility is greater than that of inorganic microminerals. Thus, these results indicate that the innate microminerals should be an important factor in establishing the micromineral requirements for growing pigs.