Effect of excess dietary copper, iron or zinc on the tocopherol and selenium status of growing pigs

Effects of Maternal Dietary Enteromorpha prolifera Polysaccharide Iron Supplement on Mineral Elements and Iron Level of Neonatal Piglets

Iron plays a key role in maternal health during pregnancy and fetal growth. Enteromorpha polysaccharide-iron (EP-Fe) as an organic iron chelate may improve the iron transmission of mother and offspring, ameliorate the poor pregnancy outcomes of sows, and alleviate the growth restriction of piglets caused by iron deficiency. This study aimed to evaluate the effects of maternal dietary supplementation with EP-Fe on reproductive performance and placental iron transmission of sows, as well as growth performance of piglets. Sixty pregnant sows at the 95th day of gestation were randomly divided into control group and EP-Fe group (EP-Fe, 139 mg kg-1). Blood samples of sows and neonatal piglets, colostrum, and tissue samples were collected on the day of delivery. The animal experiment ended at the 21st day of post-delivery. Results showed that maternal dietary EP-Fe increased colostrum iron (P < 0.05) of sows, as well as final litter weight (P < 0.05) and average daily weight of piglets (P < 0.05) during days 1-21 of lactation, as well as iron and manganese content in umbilical cord blood (P < 0.05) and hepatic iron of neonatal piglets (P < 0.01), and decreased fecal iron (P < 0.001), serum calcium (P < 0.05), phosphorus (P < 0.05), and zinc (P < 0.01) in the parturient sow. RT-qPCR results showed that Fpn1 and Zip14 in placenta, as well as TfR1 and Zip14 in duodenum of neonatal piglets, were activated by maternal EP-Fe supplement. These findings suggest that maternal dietary EP-Fe could increase iron storage of neonatal piglets via improving placental iron transport and iron secretion in colostrum, thus enhancing the growth performance of sucking piglets.

A Systematic Review and Meta-Analysis of the Effects of Various Sources and Amounts of Copper on Nursery Piglets

This study evaluated the impact of different dietary levels and sources of copper on the growth performance of nursery piglets through a combination of systematic review and meta-analysis. The database for this study was created using articles selected from major electronic databases. Data analysis involved forest plots and analysis of variance using mixed-effects models. The database included 63 articles published between 1990 and 2021, comprising 21,113 piglets in 946 treatments. Positive effects of supranutritional levels of copper from both inorganic and organic sources on the growth performance of nursery piglets were detected using Forest plots and analysis of variance (p < 0.001). Using mixed models, it was observed that piglet performance is influenced by body weight (p < 0.001), age (p < 0.001), and copper intake (p < 0.001). Both organic and inorganic sources of copper at supranutritional levels (>81 mg Cu/kg of diet) improved the performance of nursery piglets, but levels higher than 201 mg Cu/kg of diet did not further improve growth performance compared to 80-200 mg Cu/kg of diet. The feed conversion was worse in piglets fed with inorganic Cu sources (p < 0.001). In conclusion, dietary Cu supplementation influenced the weight gain and feed conversion rate in weaned piglets, particularly during the first few weeks post-weaning. Levels of 81 and 200 mg Cu/kg improved growth performance, but no further benefits were obtained for higher levels.

Effects of Different Levels of Organic Trace Minerals on Oxidative Status and Intestinal Function in Weanling Piglets

An experiment was conducted to compare the effects of replacing inorganic trace minerals (ITM) with different levels of complex organic trace minerals (OTM) on the growth performance, oxidative status, and intestinal function of piglets. Weanling piglets were assigned to five groups: a control group fed a basal diet supplemented with inorganic trace minerals and the other four groups fed basal diets supplemented with different levels of OTMs. The results showed that diets supplemented with 50 ppm Fe, 30 ppm Zn, 15 ppm Mn, and 0.2 ppm Se from OTM (L-OTM), or with 75 ppm Fe, 45 ppm Zn, 22.5 ppm Mn, and 0.3 ppm Se from OTM (M-OTM) significantly decreased the diarrhea ratio in the piglets compared with those supplemented with 100 ppm Fe, 90 ppm Zn, 40 ppm Mn, and 0.4 ppm Se from ITM. Compared with those in the ITM group, the piglets in the M-OTM group had significantly higher serum CuZnSOD, MnSOD, and GSH-Px levels. Moreover, piglets in the L-OTM and M-OTM groups had higher Sod and Gpx gene expression than those in the ITM group. Additionally, piglets in the L-OTM and M-OTM groups had significantly higher villus height than those in the ITM group, and the M-OTM group piglets had lower serum diamine oxidase content and higher ileal ZO-1 and occludin protein expression levels than those in the ITM group. These results indicate that replacing dietary ITMs with OTMs could decrease diarrhea occurrence and improve the oxidative status and intestinal barrier function in weanling piglets.

Evaluation of selenium source on nursery pig growth performance, serum and tissue selenium concentrations, and serum antioxidant status

A total of 3,888 pigs (337 × 1050, PIC, Hendersonville, TN; initially 6.0 ± 0.23 kg) were used in a 35-d study. At the time of placement, pens of pigs were weighed and allotted to one of three dietary treatments in a randomized complete block design with a blocking structure including sow farm origin, date of entry into the facility, and average pen body weight. A total of 144 pens were used with 72 double-sided 5-hole stainless steel fence line feeders, with one feeder serving as the experimental unit. For each feeder, 1 pen contained 27 gilts, and 1 pen contained 27 barrows. There were 24 replicates per dietary treatment. Diets were fed in three phases, and all contained 0.3 mg/kg added Se. A common phase 1 diet contained added Se from sodium selenite and was fed in pelleted form to all pigs from day 7 to approximately day 0. Three Se sources sodium selenite, Se yeast, and hydroxy-selenomethionine (OH-SeMet) were used to formulate three experimental diets in meal form for phase 2 (days 0 to 14) and phase 3 (days 14 to 35). During the pre-treatment period (days 7 to 0), there was a tendency (P = 0.097) of a difference in average daily feed intake between treatments, although no significant pairwise differences were observed (P > 0.05). There were no other differences in growth performance between treatments from days 7 to 0. Clinical disease attributed to Streptococcus suis was observed within the trial between days 0 and 14, and water-soluble antimicrobial therapy was administered to all treatment groups for 7 d. From days 0 to 35, pigs fed OH-SeMet tended to have decreased average daily gain (P < 0.10) and increased (P < 0.05) serum and tissue selenium concentration compared to other treatments. There was marginally significant evidence of a source × day interaction (P = 0.027) for total antioxidant capacity where the numerical increase over time was less for the OH-SeMet than sodium selenite or selenium yeast treatments. There was no difference (P > 0.05) in antioxidant status as measured by serum glutathione peroxidase or thiobarbituric acid reactive substances assay between treatments. In summary, compared to sodium selenite and selenium yeast, OH-SeMet may have a greater bioavailability as indicated by increased serum and tissue selenium concentration; however, antioxidant status was similar between treatments and OH-SeMet tended to reduce growth performance compared with pigs fed sodium selenite.

Novel edible toys as iron carrier to prevent iron deficiency of postweaned pigs

The current preventive treatment for iron deficiency in pigs is inefficient, resulting in a high prevalence of iron-deficient or anemic postweaned pigs. The aim of this study was to develop and characterize edible toys (ETs) to be used as oral iron supplements, and to assess their effect on feeding behavior and iron status of postweaned pigs. Three types of ETs, varying in sweetness, were produced by ionic gelation, using whey, sodium alginate, ferrous sulfate and atomized bovine erythrocytes. ET control (ETC) was developed without sweetener, ET1 contained 15% w/v sucrose and ET2 contained 0.03% w/v of Sucram (98% sodium saccharin, 1% neosperidine dihydrocalcone and 1% maltol). ETs were mainly composed of carbohydrates and protein, with a similar concentration of iron (2.2-2.7 mg/g). The ETs were offered to 24 postweaned pigs to measure acceptability and preference. The animals preferred ETC and ET2 over ET1. To assess the nutritional benefit of the ETs, 24 postweaned pigs were distributed into three groups: ETC (without iron), ETC-Fe (ETC with iron) and ET2-Fe (with iron and Sucram). Iron-loaded ET (ETC-Fe and ET2-Fe) significantly increased the concentration of red blood cells (from 6.1 to 7.5·10⁶ x mm³ for ETC-Fe and from 6.2 to 7.8 for ET2-Fe), hematocrit (from 32.8 to 37.9% for ETC-Fe and from 32.3 to 35.1 for ET2-Fe), serum iron (from 28.6 to 120.6 µmol/L for ETC-Fe and from 34.9 to 145.4 for ET2-Fe) and serum ferritin (from 7.8 to 18.5 µg/L for ETC-Fe and from 8.1 to 20.2 for ET2-Fe). In conclusion, the ETs developed in this study were accepted by the pigs and provided adequate iron to improve the iron status of postweaned pigs.

Exploratory Study: Excessive Iron Supplementation Reduces Zinc Content in Pork without Affecting Iron and Copper

Simple Summary

Currently, all pigs raised on intensive farms develop iron-deficiency anemia if they do not receive supplemental iron at birth. Weaning diets commonly contain high concentrations of iron, and the effect on the copper and zinc contents in pork is unknown. In this exploratory work, we determined the effect of excessive oral iron supplementation on the contents of these microminerals in pork. Surprisingly, we found that high iron doses of 3000 ppm reduced the zinc content of pork by 32–55%.

Abstract

The aim of this work was to determine in an exploratory manner the effect of excessive iron supplementation on iron, zinc, and copper contents in pork and pork offal. Pigs averaging 50 days in age and 15 ± 1.3 kg body weight were allocated to a control group (500 ppm dietary Fe) and a supplemental group (3000 ppm dietary Fe). After an iron supplementation period of 60 days, blood samples were analyzed to determine iron biomarkers, serum copper, and zinc contents. Animals were slaughtered to assess total iron, non-heme iron, heme iron, zinc, and copper contents in samples of nine meat cuts and some offal. Iron supplementation improved the iron status in pigs with increased hemoglobin and hematocrit, but did not affect serum levels of iron, zinc, and copper. Iron supplementation did not affect the heme and non-heme iron contents of the different meat cuts. Zinc contents decreased by 32–55% in meat cuts, where iron content increased in the liver, spleen, kidneys, and pancreas. No differences of zinc and copper were observed in offal samples. High concentrations of iron supplementation reduce zinc content in pork.

Effect of replacing inorganic trace minerals at lower organic levels on growth performance, blood parameters, antioxidant status, immune indexes, and fecal mineral excretion in weaned piglets

Organic trace minerals (OTMs) have the potential to replace inorganic trace minerals (ITMs), but the degree to which the dietary levels can be reduced is not well defined. This study aimed to investigate the effect of replacing of ITMs with lower levels of OTMs on growth performance, blood parameters, antioxidant status, and immune indexes in weaned piglets. The experiment was conducted in a subtropical city in Guangdong Province in South China (subtropical climate) from July to September 2018. A total of 600 pigs with an average initial BW of 8.90 kg were allotted by gender and weight to 5 treatments with 6 replicate pens per treatment. Experimental treatments: (A) Control group (a basal diet with iron, copper, manganese, and zinc from sulfates and sodium selenite providing commercially utilized levels in China of 150, 25, 40, 150, and 0.5 mg/kg, respectively). (B) 1/2 ITM group (inorganic trace minerals providing 1/2 control group levels). (C) 1/2 OTM group (1/2 control group trace mineral levels with manganese, iron, zinc, and selenium from Sel-Plex® and Cu from Bioplex®). (D) 1/3 ITM group (1/3 control group trace mineral levels from inorganic forms). (E) 1/3 OTM group (1/3 control group trace mineral levels from organic forms). The results suggest no significant effects of trace mineral sources or levels, on average daily gain (ADG) and average daily feed intake (ADFI) among different treatments during the entire experiment. The level of zinc in serum was significantly decreased in the 1/3 ITM group. The 1/3 OTM group had a significantly higher (P < 0.05) immunoglobulin G (IgG) level in serum. Fecal mineral excretion decreased significantly (P < 0.05) when decreased dietary levels of trace minerals were included at 1/2 and 1/3 levels regardless of sources. Fecal concentrations of zinc excretion were lower (P < 0.05) with 1/2 OTM supplementation than 1/2 ITMs. The present study shows that replacing high doses of ITMs with low concentrations (1/3) of OTMs does not adversely affect the growth performance of piglets. At low levels, total replacement of ITMs with OTMs improved IgG and reduced fecal excretion of copper, zinc, iron, and manganese, thereby mitigating environmental pollution.

Vitamin E and immunity

Vitamin E is the most important chain-breaking, lipid-soluble antioxidant present in body tissues of all cells and is considered the first line of defense against lipid peroxidation and it is important for normal function of the immune cells. However, vitamin E deficiency is rare in well-nourished healthy subjects and is not a problem, even among people living on relatively poor diets, both T- and B-cell functions are impaired by vitamin E deficiency. While immune cells are particularly enriched in vitamin E because of their high polyunsaturated fatty acid content, this point puts them at especially high risk for oxidative damage. Besides its immunomodulatory effects, vitamin E also plays an important role in carcinogenesis with its antioxidant properties against cancer, and ischemic heart disease with limiting the progression of atherosclerosis. Supplementation of vitamin E significantly enhances both cell mediated and humoral immune functions in humans, especially in the elderly and animals.

Effects of different dietary phytase activities on the concentration of antioxidants in the liver of growing broilers

One-hundred and fifty male chickens were used to evaluate the effects of different activities (0, 250, 500, 12 500 FTU/kg) of phytase on their performance and antioxidant concentration in the liver. The chicks were housed in 30 cages and were allocated to six replicates of five dietary treatments. All diets were formulated to be adequate in energy and protein (12.90 MJ/kg metabolizable energy, 214 g/kg crude protein), however, the negative control (NC) was lower in available P compared with the positive control (PC) (2.5 vs. 4.5 g/kg diet). The other three diets were the NC supplemented with phytase at 250, 500 and 12 500 FTU/kg (NC + 250, NC + 500 and NC + 12 500 FTU respectively). The concentration of antioxidants in the liver of the birds was determined using HPLC at 21 days of age. Low P diets (NC) reduced weight gain, however, supplementation with phytase improved weight gain to the extent that it was better than the PC at the 12 500 FTU treatment (p < 0.05). Feed conversion ratio was also improved by the high level of phytase supplement more than other treatments (p < 0.05). Feed consumption was not affected either by dietary phosphorus concentration or by different phytase supplementation. The antioxidant data showed that the unsupplemented diet with low phosphorus (NC) decreased the concentration of coenzyme Q(10) and retinol-linoleate in the liver compared with that of birds on the adequate phosphorus treatment (PC). Phytase supplementation, especially at the higher doses (500 and 12 500 FTU) increased the level of coenzyme Q(10) to the same level as the PC treatment. In addition, the highest dose (12 500 FTU) of phytase increased retinol concentration in the liver of chickens compared with those on the NC treatment. The highest inclusion level of phytase increased the alpha-tocopherol level in the liver compared with the lower levels of phytase (NC + 250 and NC + 500 FTU).

Effects of dietary iron levels on growth performance, hematological status, liver mineral concentration, fecal microflora, and diarrhea incidence in weanling pigs

An experiment was conducted in weanling pigs (Landrace x Yorkshire x Duroc) to evaluate the effects of dietary iron levels on growth performance, hematological status, liver mineral concentration, fecal microflora, and diarrhea incidence. One hundred and forty-four piglets (initial BW 5.96 +/- 0.93 kg) were randomly allotted to one of the four dietary treatments on the basis of their body weights. The basal diets for each phase (phase 1: days 0 to 14; phase 2: days 15 to 28) were formulated to contain minimal Fe and then supplemented with gradient levels of Fe (0, 50, 100, and 250 mg/kg) from ferrous sulfate. Feces were collected on days 14 and 28 and used for the analysis of microbial count and trace minerals. Eight piglets from each treatment (two piglets per pen) were bled at 0, 7, 14, 21, and 28 days to determine their hematological and plasma Fe status. In addition, two piglets from each pen (eight piglets per treatment) were killed at days 14 and 28 to determine liver mineral concentrations. Pigs fed supplemental 250 ppm Fe showed lowest overall average daily gain (linear, p = 0.036). Diarrhea incidence was linearly increased (p < 0.001) with supplemental Fe level. On days 14, coliform population in normal feces was increased (p = 0.036) linearly with supplemental Fe level, and there were higher (p = 0.043) coliform population and lower (p < 0.001) Bifidobacterium spp. in the diarrhea feces. Supplemental Fe linearly (p < 0.05) improved the total red blood cells, hemoglobin, plasma, and liver (p = 0.109) Fe status of pigs and also increased (linear and quadratic, p < 0.001) the fecal excretion of Fe on days 14 and 28. It is concluded that increasing the dietary iron levels in piglets improved their hematological status and liver Fe content; however, higher dietary Fe levels might also be associated with the increased diarrhea incidence.

Effect of supplemental iron on finishing swine performance, carcass characteristics, and pork quality during retail display1

Crossbred pigs (n = 185) were used to test the effects of dietary Fe supplementation on performance and carcass characteristics of growing-finishing swine. Pigs were blocked by BW, allotted to pens (5 to 6 pigs/pen), and pens (5 pens/block) were allotted randomly to either negative control (NC) corn-soybean meal grower and finisher diets devoid of Fe in the mineral premix, positive control (PC) corn-soybean meal grower and finisher diets with Fe included in the mineral premix, or the PC diets supplemented with 50, 100, or 150 ppm Fe from Availa-Fe (an Fe-AA complex). When the lightest block averaged 118.2 kg, the pigs were slaughtered, and bone-in pork loins were collected during fabrication for pork quality data. During the grower-I phase, there was a tendency for supplemental Fe to reduce ADG linearly (P = 0.10), whereas in the grower-II phase, supplemental Fe tended to increase ADG linearly (P = 0.10). Even though pigs fed NC had greater G:F during the finisher-I phase (P < 0.05) and across the entire trial (P = 0.07), live performance did not (P > or = 0.13) differ among dietary treatments. There were linear increases in 10th-rib fat depth (P = 0.08) and calculated fat-free lean yield (P = 0.06); otherwise, dietary Fe did not (P > 0.19) affect pork carcass muscling or fatness. Moreover, LM concentrations of total, heme, and nonheme Fe were similar (P > 0.23) among treatments. A randomly selected subset of loins from each treatment was further fabricated into 2.5-cm-thick LM chops, placed on styrofoam trays, overwrapped with polyvinyl chloride film, and placed in coffin-chest display cases (2.6 degrees C) under continuous fluorescent lighting (1,600 lx) for 7 d. During display, chops from NC-fed pigs and pigs fed the diets supplemented with 100 ppm Fe tended to have a more vivid (higher chroma value; P = 0.07), redder (higher a* value; P = 0.09) color than LM chops of pigs fed 50 ppm of supplemental Fe. Moreover, greater (P < 0.01) redness:yellowness ratios in chops from pigs supplemented with 100 ppm Fe indicated a more red color than chops from PC-fed pigs or pigs fed diets supplemented with 50 ppm Fe. In conclusion, however, increasing dietary Fe had no appreciable effects on performance, carcass, or LM characteristics, suggesting that current dietary Fe recommendations are sufficient for optimal growth performance, pork carcass composition, and pork quality.

Effect of phosphorylated mannans and pharmacological additions of zinc oxide on growth and immunocompetence of weanling pigs

Three experiments were conducted to evaluate the efficacy of phosphorylated mannans (MAN) and pharmacological levels of ZnO on performance and immunity when added to nursery pig diets. Pigs (216 in each experiment), averaging 19 d of age and 6.2, 4.6, and 5.6 kg of BW in Exp. 1, 2, and 3, respectively, were blocked by BW in each experiment, and penned in groups of six. A lymphocyte blastogenesis assay was performed in each experiment to measure in vitro lymphocyte proliferation response. In Exp. 1, diets were arranged as a 2 x 2 factorial with two levels of Zn (200 and 2,500 ppm) and two levels of MAN (0 and 0.3% from d 0 to 10, and 0 and 0.2% from d 10 to 38). Zinc oxide increased (P < 0.05) ADG, ADFI, and G:F from d 0 to 10, and ADG and ADFI from d 10 to 24. In Exp. 2, diets were arranged as a 2 x 3 factorial with two levels of Zn (200 and 2,500 ppm) and three levels of MAN (0, 0.2, and 0.3%). Pigs fed 2,500 ppm Zn from d 0 to 10 had greater (P < 0.05) ADG, ADFI, and G:F than pigs fed 200 ppm Zn. From d 10 to 24, ADG was similar when pigs were fed 200 ppm Zn, regardless of MAN supplementation; however, ADG increased (P < 0.05) when 0.2% MAN was added to dietscontaining 2,500 ppm Zn (MAN x Zn interaction, P < 0.05). In Exp. 3, diets were arranged as a 2 x 3 factorial with two levels of MAN (0 and 0.3%) and three levels of Zn (200, 500, and 2,500 ppm). Zinc was maintained at 200 ppm from d 21 to 35, so only two dietary treatments (0 and 0.3% MAN) were fed during this period. Average daily gain was greater (P < 0.05) from d 7 to 21 when pigs were fed 2,500 ppm Zn compared with pigs fed 200 or 500 ppm Zn. The addition of MAN improved (P < 0.05) G:F from d 7 to 21 and d 0 to 35. Lymphocyte proliferation of unstimulated cells and phytohemagglutinin-stimulated cells was decreased (P < 0.05) in cells isolated from pigs fed MAN compared with cells isolated from pigs fed diets without MAN. Lymphocyte proliferation of pokeweed mitogen-stimulated cells isolated from pigs fed MAN was less (P < 0.05) than for pigs fed diets devoid of MAN when diets contained 200 ppm Zn; however, MAN had no effect on lymphocyte proliferation when the diet contained 500 or 2,500 ppm Zn (MAN x Zn interaction, P < 0.05). Although the magnitude of response to MAN was not equivalent to that of pharmacological concentrations of Zn, MAN mayimprove growth response when pharmacological Zn levels are restricted.

Effects of vitamin E and C supplementation on performance, in vitro lymphocyte proliferation, and antioxidant status of laying hens during heat stress

Vitamin E (dl-alpha-tocopheryl acetate) was evaluated for its effects on performance, lymphocyte proliferation, and antioxidation in layers during heat stress. In Trial 1, 25, 45, or 65 IU of vitamin E/kg were fed to four replicated pens (five hens/cage) of DeKalb Delta or Hy-Line W-36 per treatment starting at 20 wk of age. At 34 wk of age, hens were heat-stressed at diurnal temperature ranging from 21 C to 35 C for 3 wk. The performances of hens not exposed to heat stress were not influenced by supplemental vitamin E. Supplemental vitamin E did not affect egg production; however, egg mass was greater (P < 0.05) with supplementation of 65 IU of vitamin E/ kg during heat stress. Egg yolk was significantly increased (P < 0.04) when hens were fed 45 and 65 lU/kg compared with the control vitamin E level (25 lU/kg). Haugh units were higher (P < 0.01) for hens fed 65 IU of vitamin E/kg compared to 25 and 45 lU/kg. Lymphocyte proliferative responses to concanavalin A (Con A) and Salmonella typhimurium lipopolysaccharide (LPS) were greater (P < 0.0001) in hens fed 45 and 65 IU of vitamin E/kg during heat stress. Strain had no effect on any of the parameters measured. In Trial 2, a 2 x 2 factorial was designed to test effects of vitamin C in drinking water (0 and 1,000 ppm) and dietary vitamin E (25 and 65 IU/kg). Eight replications per treatment with four hens per replication cage were heat-stressed at constant temperature of 35 C for 3 wk. Egg production and egg mass were higher when hens were fed 65 IU of vitamin E/kg than when hens were fed 25 lU/kg (81.5 vs. 75.9%, P < 0.03 and 48.2 vs. 44.6 g, P < 0.03, respectively). Yolk solids weight for the 65 IU vitamin E/kg group was higher (P < 0.01) compared to the 25 IU/kg group. ConA and LPS mitogenic responses were greater in hens fed 65 IU of vitamin E (P < 0.001 or P < 0.003, respectively) or 1,000 ppm of vitamin C (P < 0.001 or P < 0.002, respectively). The combination of 65 IU vitamin E/kg and 1,000 ppm vitamin C showed the highest ConA and LPS mitogenic responses among the treatments. No interaction effects of the two vitamins on production measurements or lymphocyte proliferative responses were observed. TBA values in egg yolk and plasma of hens fed 65 IU of vitamin E/kg were lower (P < 0.0001) than those of hens that received 25 IU of vitamin E/kg. These results suggest that vitamin E supplementation at 65 IU/kg diet may enhance production, induction of in vitro lymphocyte proliferation by ConA and LPS, and antioxidant properties of egg yolks and plasma of White Leghorn hens during heat stress and that supplementation of 1,000 ppm vitamin C may further enhance in vitro lymphocyte proliferative responses of hens during heat stress.

Adverse effects of Escherichia coli infection of turkeys were not alleviated by supplemental dietary vitamin E

Two experiments were conducted to determine the influence of dietary vitamin E on the response of young male turkeys to Escherichia coli infection. A complete factorial arrangement of two concentrations of supplemental dietary vitamin E (12 or 300 IU/kg as dl-alpha-tocopheryl acetate) and infection or no infection of turkeys with E. coli was used in both experiments. In Experiment 1, each dietary treatment was fed to four pens of turkeys from 1 to 28 d of age. At 28 d, turkeys in two pens per dietary treatment received an injection of 3.0 x 10(7) E. coli cells into the left and right thoracic air sacs. All turkeys were necropsied 7 d after E. coli injection and the incidence and severity of lesions in air sacs, lungs, pericardium, and liver were determined. The same dietary vitamin E treatments were used in Experiment 2. Each diet was fed to eight pens of turkeys from 1 to 47 d of age. At 47 d, turkeys in four pens per dietary treatment received an injection of 3.0 x 10(7) cells of the same E. coli used in Experiment 1 into the left and right thoracic air sacs. All turkeys were necropsied as in Experiment 1 at 54 d of age. Weight gain and efficiency of feed utilization were impaired markedly by E. coli infection during the 7 d after injection. Livability also was decreased by E. coli infection in Experiment 1 but not in Experiment 2. Adverse effects of E. coli on performance and livability were not affected by dietary vitamin E concentration. Lesions observed in turkeys that received E. coli injection ranged from mild to severe, with the most severe lesions observed in air sacs. Lung lesions were observed frequently but were less severe than in air sacs. Dietary concentration of vitamin E had no effect on incidence or severity of lesions in air sacs or lungs. Overall, the results of these experiments show that adding 300 IU of vitamin E/kg of diet did not alleviate the adverse effects of E. coli infection in young turkeys.

Influence of supplementing corn-soybean meal diets with vitamin E on performance and selected physiological traits of male turkeys

Three experiments were conducted to determine the effects of supplementing practical diets of male turkeys with dl-alpha-tocopheryl acetate (TA). In Experiment 1, a factorial arrangement of dietary treatments [0, 12, 50, 150, and 300 IU TA/kg with 0 or 300 mg ascorbic acid (AA)/kg] was used. These 10 treatments were fed to poults from 1 to 41 d of age. From 41 to 118 d of age, the AA treatments were discontinued, and the 300 IU TA treatment groups were changed to 12 IU TA/kg. Neither TA nor AA treatments affected 41-d BW, feed to gain ratio (FE), or livability. No effects of dietary TA concentrations on turkey performance were observed through 118 d of age alpha-Tocopherol (TOC) concentrations of plasmas and livers were increased by increments of dietary TA, with substantial liver storage when toms were fed 150 IU TA/kg from 1 to 118 d. Supplementing diets with 0, 25, 50, 75, or 100 IU TA/ kg in Experiments 2 and 3 had no effect on performance of toms through 119 and 105 d, respectively. alpha-Tocopherol concentrations of plasma and red blood cells (RBC) increased linearly with increments of dietary TA. The same was true for livers in Experiment 2. Susceptibility of RBC to hemolysis induced by 400 microM t-butyl hydroperoxide (TBH) in Experiment 2 decreased with increasing dietary TA, and these decreases corresponded to increases in TOC concentration of RBC. However, the relationships between hemolysis and dietary TA or RBC TOC were inconsistent in Experiment 3 and varied according to concentration of TBH (200, 300, or 400 microM) and age of the toms. At 105 d of age, RBC of toms fed no supplemental TA were resistant to hemolysis, irrespective of dietary TA and TBH concentration. In Experiment 3, there were no indications of dietary TA effects on plasma peroxide concentration or activity of plasma creatine kinase. A positive relationship between dietary TA and blastogenic responses of blood lymphocytes was observed with concanavalin A when toms were at 44 d but not at 23 or 86 d of age. The overall data indicate that corn-soybean meal diets containing from 6 to 20 IU TOC/kg, but no supplemental TA supported satisfactory performance and well-being of male turkeys from 1 d of age to market ages when the turkeys were free of disease, as was true in the research reported here.

Efficacy of dietary and injected vitamin E for poults

An experiment was conducted to compare the efficacy of two dietary sources and an injectable form of vitamin E (VE) to improve the VE status of poults. Six of the treatments consisted of a factorial arrangement of three concentrations and two sources of dietary VE. Turkeys in these treatments received 12, 80, or 150 IU of either dl-alpha-tocopheryl acetate or d-alpha-tocopherol (d-alpha-TOC)/kg of diet. The seventh treatment consisted of a single subcutaneous injection of d-alpha-TOC at 1 d of age. Poults in this treatment were subcutaneously injected in the dorsal area of the neck with 25 IU of d-alpha-TOC, this amount being approximately equivalent to the amount poults would consume if their diet was supplemented with 150 IU of VE/kg during their 1st wk of life. Concentration, source, or route of VE administration did not affect growth parameters, plasma creatine kinase, plasma triglycerides, or liver lipid peroxidation as measured by the thiobarbituric acid reactive substances assay (TBARS). Plasma, red blood cells (RBC), and liver alpha-TOC decreased from hatching to 14 d of age in poults fed either source of VE. The use of 80 or 150 IU of dietary VE (either source) reduced (P < 0.05) the extent of depletion of alpha-TOC at all ages and also reduced the susceptibility of RBC to hemolysis. There was no effect of source of dietary VE on concentration of alpha-TOC in plasma, RBC, or liver, or on RBC hemolysis. Subcutaneous injection of 25 IU of d-alpha-TOC at Day 1 increased (P < 0.05) alpha-TOC concentration until 7 d of age. Also, d-alpha-TOC injection reduced (P < 0.05) RBC susceptibility to hemolysis through 21 d of age. Data showed that one single subcutaneous injection of 25 IU of d-alpha-TOC at 1 d of age was as effective as 80 IU or more of dietary VE through 21 d to improve the alpha-TOC status of poults.

Lipid peroxidation status as an index to evaluate the influence of dietary fats on vitamin E requirements of young pigs

The aims of the present study were to establish a suitable criterion for estimating the vitamin E requirement for young pigs, and to investigate the influence of dietary fats on the requirement of this nutrient. In Expt 1 weaned pigs were given a semi-purified diet supplemented with 0, 20, or 100 mg DL-alpha-tocopheryl acetate/kg. Pigs in Expt 2 were fed on diets containing 10 g sunflower oil (SO) stripped of vitamin E/kg in diets 1 and 2, 100 g SO/kg in diets 3 and 4, and 100 g tallow/kg in diet 5. Diets 2, 4 and 5 were supplemented with DL-alpha-tocopheryl acetate at 20 mg/kg for 0-28 d and 50 mg/kg for 29-56 d of the experiment respectively. Results showed that vitamin E concentrations in plasma and tissues reflected dietary levels of vitamin E. No apparent clinical signs of vitamin E deficiency were observed, but pigs fed on diets without vitamin E supplementation showed a higher (P < 0.05) lipid peroxidation status as indicated by thiobarbituric acid-reactive substances in erythrocytes, and ethane and pentane levels in exhaled gases than those fed on supplemental diets. This indicated that the former was deficient in vitamin E. Data in Expt 1 suggested that supplementation with 20 mg DL-alpha-tocopheryl acetate/kg is adequate for young pigs when the diet contains 30 g lard/kg. However, results in Expt 2 showed that this level was inadequate when the diet contains 100 g SO/kg or its equivalent to 70 mg polyunsaturated fatty acids (PUFA)/g. Vitamin E and lipid peroxidation status of pigs were affected by both dietary vitamin E and dietary PUFA. This demonstrates that the requirement for vitamin E in young pigs increases as PUFA levels in the diet increase. The present study shows that lipid peroxidation response of pigs is a suitable index to evaluate vitamin E requirements.

Fat-soluble vitamin nutrition for dairy cattle

The need for supplementation of dairy cow diets with fat-soluble vitamins depends on the amount of vitamins naturally present in the diet, the availability of dietary vitamins, and the vitamin utilization rate of the animal. Fresh forage contains ample amounts of the vitamin A precursor beta-carotene as well as vitamin E. Irrespective of the dietary amount, however, the availability of vitamins A, D, and E, as well as beta-carotene, can be adversely influenced by poor fat digestion, as commonly occurs due to enteric disease in young calves. In addition, high-grain diets appear to increase the amount of ruminal vitamin destruction and may thus increase vitamin requirements. The vitamin utilization rate may be increased by inflammation as well as dietary and environmental factors. The factors influencing vitamin availability and utilization rate should be considered when formulating rations. Because the vitamin requirement is variable, blood concentrations of vitamins should be monitored when conditions such as poor fertility, weak calves, and poor immune response are present.