Effect of dietary levels of vitamin E (all-rac-tocopheryl acetate) with or without added fat on weanling pig performance and tissue alpha-tocopherol concentration

Two experiments involving 496 cross-bred pigs evaluated the efficacy of various dietary levels of vitamin E, with or without supplemental fat, on postweaning pig performance and weekly serum and terminal tissue alpha-tocopherol concentrations. The first trial involved 248 pigs weaned at an average of 15 d of age and 4.8 kg BW. The experiment was a randomized complete block design conducted in seven replicates. Vitamin E was added as dl-alpha-tocopheryl acetate at 0, 20, 40, 60, 80, 100, 150, or 200 IU/kg diet. Pigs were bled initially and at 7-d intervals for a 42-d period. Liver and s.c. adipose tissue samples were collected from six pigs per treatment group at 42 d. In Exp. 2, a 2 x 4 factorial arrangement of treatments in a randomized complete block design was conducted in seven replicates. The experiment used a total of 248 pigs weaned at 19 d of age and averaged 6.4 kg BW. Four vitamin E levels (0, 20, 40, and 60 IU/kg diet) and two added fat levels of 0 or 5% were fed for 35 d. Four pigs per treatment pen were bled weekly, and at 35 d a total of four pigs per treatment group were killed and liver, heart, and s.c. adipose tissues were collected and analyzed for alpha-tocopherol. The basal diet in both experiments contained an average 7.9 IU for period 1, and later diets averaged 11.0 IU vitamin E/kg. In both experiments serum alpha-tocopherol concentrations declined from weaning to 7 d after weaning and continued to decline each week after weaning when the basal diets were fed. Serum alpha-tocopherol concentrations increased (P < 0.01) each week as the dietary vitamin E level increased in both experiments. In Exp. 2, when fat was added to the diet serum alpha-tocopherol concentrations were higher (P < 0.01) than in diets without added fat. Liver, heart muscle, and adipose tissue alpha-tocopherol concentrations increased (P < 0.01) as vitamin E level increased, but at the higher dietary vitamin E level the liver surpassed the adipose tissue in its alpha-tocopherol concentration. Liver and adipose alpha-tocopherol concentrations were higher (P < 0.01) when fat was added to the diet. These results indicate that supplementation of 40 to 60 IU/kg diet with added fat resulted in a relatively constant balance of serum and tissue concentration of alpha-tocopherol during the nursery period, but when fat was not supplemented a dietary vitamin E level of 80 to 100 IU/kg diet may be needed. The current NRC recommendations for vitamin E for the pig from 5 to 20 kg BW may need to be reevaluated.     

Assessment of the influence of dietary vitamin E on sows and offspring in three parities: reproductive performance, tissue tocopherol, and effects on progeny

Sixty crossbred (Yorkshire-Hampshire X Duroc) gilts were fed one of four corn-soybean meal diets fortified with .3 ppm Se and 0, 16, 33, or 66 IU of DL-alpha-tocopheryl acetate/kg. The study was conducted over a three-parity period to evaluate sow reproductive performance and the vitamin E tissue status of both sows and progeny at various time periods postcoitum and(or) postpartum. The basal diet averaged 8.4 mg of alpha-tocopherol/kg and .38 ppm of Se. Although litter size at birth was lowest (P less than .15) when sows were fed the basal diet, a higher incidence of agalactia when sows were fed the lower dietary vitamin E levels resulted in an increased (P less than .05) litter size at 7 d postpartum as dietary vitamin E increased. Sow serum alpha-tocopherol increased (P less than .01) at each measurement period as dietary vitamin E level increased. Colostrum and milk alpha-tocopherol concentrations increased (P less than .01) as dietary vitamin E level increased, and colostrum values were three to five times higher than at later milks. Colostrum alpha-tocopherol declined by parity from sows fed less than or equal to 16 IU/kg but was similar at each parity for sows fed greater than or equal to 33 IU/kg, resulting in a dietary vitamin E x parity interaction (P less than .01). The Se content of sow milk declined with parity but was not affected by dietary vitamin E level. Sow liver tocopherol at weaning (28 d postpartum) increased (P less than .01) as dietary vitamin E increased and increased with parity (P less than .05). Pig serum and liver alpha-tocopherol concentrations were elevated at birth and 7 and 28 d of age as sow dietary level of vitamin E increased. Upon weaning, pigs were fed a torula yeast-dextrose diet that contained 3.0 mg of alpha-tocopherol/kg and .32 ppm Se for a 28-d postweaning period. Liver and serum alpha-tocopherol concentrations declined during the postweaning period. Evidence of the vitamin E deficiency occurred at 28 d postweaning in the progeny from sows fed the basal diet or 16 IU of vitamin E; the incidence was more prevalent in the pigs from Parities II and III. These results suggest that a supplemental level of 16 IU of vitamin E/kg of diet was inadequate for the reproducing sow; higher levels are justified, particularly when females are retained in the herd for several parities.     

Influence of two supplemental vitamin E levels and weaning age on performance, humoral antibody production and serum cortisol levels of pigs

Three trials using 156 Yorkshire x Hampshire x Duroc crossbred pigs (avg initial wt, 7.9 kg) were conducted to evaluate the effects of two supplemental dietary vitamin E (11 vs 220 IU/kg of diet) and weaning age (21, 28 or 35 d) on performance and immunocompetence of pigs. Supplemental vitamin E (220 IU/kg of diet) increased (P less than .01) serum concentrations of vitamin E for all weaning ages compared with pigs fed 11 IU of vitamin E/kg of diet. However, supplemental vitamin E did not affect performance, serum cortisol concentration or the primary and secondary antibody response to sheep red blood cells. As weaning age increased, weekly ADG and avg daily feed intake increased linearly (P less than .01). Cortisol levels decreased during the 1st wk following weaning and then increased linearly (P less than .01) over time; pigs weaned at 35 d of age had higher (P less than .01) cortisol values initially and over time than pigs weaned at 21 and 28 d. Pigs weaned at 35 d had a higher (P less than .01) primary response to sheep red blood cells than pigs weaned at 21 and 28 d of age, but this effect was not observed for the secondary response. There were no interactive effects (P greater than .10) of dietary vitamin E level and weaning age. In summary, the highest level of supplemental vitamin E increased serum vitamin E concentration but did not affect performance, cortisol levels or one test of the immune response, antibody titers to red blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

Study of immune response in pigs fed with high vitamin E-dosages

The effects of long-term vitamin E-supplementation on phagocytic cells, lymphocyte sub-populations, and SWC3+ cell count were studied in pigs. Eighteen weaned pigs were divided into three groups: 1) 100 mg DL-alpha tocopheryl acetate/kg diet, 2) 200 mg DL-alpha tocopheryl acetate/kg diet, 3) control group (basic feed with 10 mg DL-alpha tocopheryl acetate/kg diet). The examination of the immune indices was performed on day 120 of feeding the supplemented diets. The higher dietary levels of vitamin E resulted in increased serum concentration of alpha-tocopherol for both experimental groups (p < 0.05) and there were no significant differences in counts of CD2+, CD4+, CD8+, B lymphocytes nor SWC3+ cells among the groups. Similarly, vitamin E supplementation did not affect the functions of phagocytic cells tested.     

Importance of diet of dam and colostrum to the biological antioxidant status and parenteral iron tolerance of the pig

Fifteen second-parity sows were used to determine the importance of vitamin E (E) and selenium (Se) supplementation of the sow's diet and colostrum consumption by the neonatal pig on tolerance to parenteral iron. Selenium (.1 ppm) and E (50 IU/kg) supplementation of the diet of the sow increased plasma tocopherol and Se concentrations, but did not increase plasma glutathione peroxidase (GSH-Px) activity. Colostrum had greater concentrations of E (primarily alpha-tocopherol) and Se than milk. Plasma biological antioxidant status (tocopherol level and GSH-Px activity) of pigs at birth was very low, but by 2 d of age had increased, especially in alpha-tocopherol (nearly a 20-fold increase). Liveability and body weight gain of pigs were not affected by the pre-colostrum iron injection (200 mg Fe as gleptoferron); however, plasma tocopherol concentrations of Fe-injected pigs were lower and plasma Se concentration and GSH-Px activities were higher at 2 d of age than values of pigs not receiving parenteral Fe. Supplementation of the dam's diet with E and Se maintained high tocopherol and Se levels in her colostrum and milk and a high biological antioxidant status in her pigs throughout the nursing period.     

Vitamin E requirement of growing swine

The vitamin E requirement of growing pigs was estimated on the basis of prevention of morphological signs of deficiency. Five groups of pigs were fed a barley-based diet low in vitamin E that contained 16 mg of DL-alpha-tocopheryl acetate equivalents/kg and .1 ppm of Se for 4 wk (depletion I). This period was followed by 7 wk of supplementation, during which the groups received 0, 15, 45, 135 and 405 mg of supplemental DL-alpha-tocopheryl acetate/kg diet. Finally, all the animals were fed the low vitamin E diet for 7 wk (depletion II). To follow the vitamin E concentration in serum and tissues, blood samples were collected and biopsies were taken from skeletal muscle, adipose tissue and the liver throughout the experiment. The peak vitamin E value was observed in the liver, followed by the adipose tissue and then skeletal muscle. The liver responded rapidly to changes in dietary vitamin E intake, whereas the adipose tissue and the skeletal muscle reacted at a slower rate. In spite of the abundant occurrence of the different vitamin E isomers in the feed, alpha-tocopherol was the main isomer detected both in the serum and in the tissues. The activity of glutathione peroxidase in serum increased with age but was independent of the serum vitamin E concentration. In the unsupplemented group all animals suffered from the vitamin E and Se deficiency syndrome (VESD) in an acute or chronic form. A total of 31 mg of DL-alpha-tocopheryl acetate/kg diet (16 mg of naturally occurring vitamin E and 15 mg as supplementation) equivalent to 2.5 IU vitamin E/g polyunsaturated fatty acids (PUFA) was enough to prevent the development of VESD. In view of the large individual variations of vitamin E concentration in target organs, and to obtain a certain safety margin for prevention of VESD in growing pigs, a supplement of 30 mg of DL-alpha-tocopheryl acetate/kg diet is recommended.     

An evaluation of natural (RRR-alpha-tocopheryl acetate) and synthetic (all-rac-alpha-tocopheryl acetate) vitamin E fortification in the diet or drinking water of weanling pigs

Three experiments conducted with weanling pigs evaluated the effects of vitamin E added to the drinking water or diet on plasma and tissue alpha-tocopherol concentrations. When natural or synthetic vitamin E was used, it was added at an IU-equivalent basis, but natural vitamin E was 73.5% (mg basis) of the synthetic vitamin E. Experiment 1 used 18-d-old weanling pigs (n = 120) in a 3 x 2 factorial arrangement of treatments in a randomized complete block design with 4 replicates. The first factor evaluated the dietary levels of natural vitamin E (RRR-alpha-tocopheryl acetate) added at 0, 50, or 300 IU/kg, whereas the second factor was the natural vitamin E added to the drinking water at 0 or 100 IU/L. Pigs were bled at periodic intervals, and 1 pig per pen was killed at the end of the 21-d trial and tissues (liver, heart, lung, and loin) were collected for alpha-tocopherol analysis. When vitamin E was not added to the diet or water, plasma alpha-tocopherol declined over the 21-d period. Although there were some interactions (P < 0.01), tissue and plasma alpha-tocopherol concentrations increased linearly when vitamin E was added to the diet or water. Experiment 2 was a 3 x 2 factorial in a randomized complete block design with 4 replicates. A total of 96 pigs weaned at 18 d of age, with an initial BW of 6.2 kg, were fed a nonvitamin E fortified diet, but natural or synthetic (all-rac-alpha-tocopheryl acetate) vitamin E was added to their drinking water at 50, 100, or 150 IU/L. Pigs were bled at 0, 3, 7, 10, 14, and 21 d postweaning, with tissues (liver, lung, heart, and loin) collected for alpha-tocopherol analysis at d 21. The results indicated that plasma alpha-tocopherol concentrations increased (P < 0.01) as vitamin E increased, with greater tissue alpha-tocopherol concentrations (P < 0.01) when natural vitamin E was provided. Experiment 3 was conducted in 2 replicates, but pigs (n = 60) were not provided vitamin E in the diet or water for 7 d postweaning, and then natural or synthetic vitamin E was added to the drinking water as in Exp. 2 (50, 100, or 150 IU/L). Pigs were bled at 0, 2, 4, 6, 8, 10, and 24 h after being provided vitamin E to evaluate the absorption from each vitamin E source and level. Plasma alpha-tocopherol increased quadratically (P < 0.01) and plateaued at 8 to 10 h for each treatment group. These results indicate that adding vitamin E to the pig's water supply at weaning was more effective in increasing plasma alpha-tocopherol than when it was added to the diet during the initial 14 d postweaning, and that natural vitamin E was a superior source compared with synthetic vitamin E.     

Influence of dietary rapeseed oil, vitamin E, and copper on the performance and the antioxidative and oxidative status of pigs.

We investigated the effects of dietary copper and vitamin E in diets containing 6% rapeseed oil on the performance and the antioxidative and oxidative status of growing pigs. The 10 dietary treatments consisted of a basal diet (9 mg of vitamin E/kg feed, 15 mg of Cu/kg feed), the basal diet + 6% rapeseed oil (Diet 1; 18 mg of vitamin E/kg feed, 15 mg of Cu/kg feed), and Diet 1 plus supplements of vitamin E (0, 100, and 200 mg of dl-alpha-tocopheryl acetate/kg feed) and copper (0, 35, and 175 mg of Cu/ kg feed) in a 3 x 3 factorial arrangement of treatments. Eight or nine pigs were given ad libitum access to each diet from 25 to 100 kg of live weight. The inclusion of rapeseed oil tended (P < .10) to improve ADG and feed utilization. Compared with the addition of 35 mg of Cu/kg, the addition of 175 mg/kg improved growth rate and increased feed intake early in the experiment, but, over the total experiment, neither 35 nor 175 mg of Cu/kg affected performance. Compared with the addition of 100 mg of vitamin E/kg or no addition, the addition of 200 mg/kg reduced ADG over the total experiment (P = .05). The antioxidative and oxidative status of the pigs was evaluated in terms of blood and liver concentrations of antioxidants (alpha-tocopherol, ascorbic acid, vitamin A, superoxide dismutase, glutathione peroxidase), prooxidants (Cu), concentrations of lipids (triglycerides and cholesterol), fatty acid composition, thiobarbituric acid-reactive substances (TBARS), and clinical chemical (creatine kinase and glutamate-oxaloacetate-transaminase) and hematological variables that indicate the level of oxidative stress. There were no vitamin E deficiency signs or increased oxidative stress in pigs fed low dietary vitamin E levels, and no prooxidative effect of Cu was found. Increasing dietary levels of vitamin E increased the concentration of alpha-tocopherol in plasma and liver. Supplementation with Cu increased liver concentrations of Cu and alphatocopherol. The progression in liver TBARS was reduced by the addition of vitamin E and Cu. The addition of rapeseed oil changed the fatty acid composition of liver, increased alpha-tocopherol concentration in plasma and Cu concentration in liver, and reduced the rate of lipid oxidation in liver. In conclusion, even though the effects were minor, vitamin E, Cu, and rapeseed oil improved the antioxidative status of the live pigs.     

Added dietary pyridoxine, but not thiamin, improves weanling pig growth performance

We conducted two trials to determine the effects of added dietary pyridoxine (vitamin B6) or thiamin (vitamin B1) on growth performance of weanling pigs. In Exp. 1, weanling pigs (n = 180, initially 5.55 +/- .84 kg, and 21 +/- 2 d of age) were fed either a control diet (no added pyridoxine or thiamin) or the control diet with added thiamin (2.8 or 5.5 mg/kg) from thiamin mononitrate or pyridoxine (3.9 or 7.7 mg/kg) from pyridoxine HC1. These five diets were fed in meal form in two phases (d0 to 14 and 14 to 35 after weaning), with identical vitamin concentrations in both phases. From d 0 to 14 after weaning, pigs fed added pyridoxine had increased (quadratic, P < .05) ADG and ADFI; pigs fed 3.9 mg/kg of added pyridoxine had the greatest improvement. From d 14 to 35 and 0 to 35, ADG and ADFI increased (linear P = .06) for pigs fed increasing pyridoxine. Growth performance was not improved by added thiamin. In Exp. 2, weanling pigs (n = 216, initially 6.08 +/- 1.13 kg, and 21 +/- 2 d of age) were fed a control diet or the control diet with 1.1, 2.2, 3.3, 4.4, or 5.5 mg/kg of added pyridoxine from pyridoxine HCl. From d 0 to 14 after weaning, increasing pyridoxine increased (quadratic, P < .05) ADG and ADFI; pigs fed 3.3 mg/kg of added pyridoxine had the greatest ADG and ADFI. Break-point analysis suggested a requirement estimate of 3.3 and 3.0 mg/kg of added pyridoxine to maximize ADG and ADFI, respectively. From d 14 to 35 or 0 to 35, increasing pyridoxine had no effect (P > .10) on pig growth performance. These results suggest that adding 3.3 mg/kg of pyridoxine (7.1 to 7.9 mg/kg of total pyridoxine) to diets fed from d 0 to 14 after weaning can improve pig growth performance.     

Effect of chromium tripicolinate supplementation on porcine immune response during the periparturient and neonatal period

A total of 36 gilts were used to assess the effects of Cr tripicolinate supplementation on immune response in sows and their offspring during the periparturient and neonatal period. Gilts were raised from weaning to reproductive age on diets with either 0 (-Cr) or 200 (+Cr) ppb supplemental Cr from CrPic. Subsequently, 22 gilts (9 -Cr and 13 +Cr) in parity 1 and 16 sows in parity 2 (7 -Cr and 9 +Cr) underwent immune status testing. Only sows that completed all procedures in parity 1 were included in parity 2. Sows were immunized with ovalbumin about 3 wk (d 0), and again 14 d later for gilts, prior to anticipated farrowing, and serum was collected on d 0 and at 14-d intervals for a total of four samples. Serum was collected from five to six pigs/litter at 24 h after birth, three or six pigs/litter the day after weaning (25 d of age) in parity 1, and three pigs/litter the day of weaning (20 d of age) in parity 2. Milk was collected at 1 h (colostrum), 6.5 d (early), and 19 d (late) after farrowing. The only effect of Cr on total immunoglobulin (Ig) concentration was on sow serum IgG (21.7 and 24.1 mg/mL for -Cr and +Cr, respectively; P = 0.08) and IgM (11.0 and 12.5 mg/mL; P = 0.06) on d 0. No effect (P > 0.15) of Cr was observed on the IgG antibody response to ovalbumin, but Cr was associated (P < 0.10) with a decreased IgM antibody response to ovalbumin beginning on d 14. In parity 2, colostral total IgG increased (80.6 and 92.4 mg/mL for parity 1 and 2, respectively; P = 0.06), which was reflected in the neonates at 24 h after birth (33.6 and 39.7 mg/mL; P = 0.01) and at weaning (7.3 and 13.3 mg/mL; P < 0.001). Supplementation of Cr tripicolinate had minimal effects on humoral antibody response of the dam or its transfer to the neonate; however, parity greatly influenced the concentrations of immunoglobulins in the milk and their transfer to the neonate.     

Effect of nutritional status, age at weaning and room temperature on growth and systemic immune response of weanling pigs

Two experiments were conducted to determine the effect of nutritional status, age at weaning and room temperature on growth and immune response of pigs. In the first experiment, 72 pigs were weaned at either 2 or 3 wk and fed either a complex, simple-adequate or simple-inadequate diet for a 24-d period. Total antibody (TAb) titers in response to injections of human red blood cells (RBC) on either 0, 4, or 16 d postweaning were not affected by age at weaning or dietary treatments even though the nutritional status was compromised to such an extent that pigs fed the simple-adequate diet gained at one-half the rate (.172 vs .349 kg/d) of pigs fed the complex or simple-adequate diets (P less than .01). In Exp. 2, the immunological response of 144 pigs weaned at 3 wk were evaluated at 4 and 8 d postweaning. Pigs were weaned into rooms that averaged either 25 or 18 C, and were fed either a complex or simplex-adequate diet at either ad libitum (AL) or restricted (Res) levels for a 24-d period. Restriction of either the complex or simple diet for the first 16 d of the trial drastically reduced (P less than .01) the growth rates of Res pigs compared with AL pigs (.042 vs .236 kg/d). There were no differences in skinfold thickness (Sf) or TAb, 2-mercaptoethanol sensitive (MEs) and resistant (MEr) antibody titers when pigs were inoculated with phytohemagglutinin-P (PHA-P) or RBC at 4 d postweaning regardless of room temperature, diet source or feeding level.(ABSTRACT TRUNCATED AT 250 WORDS)     

Weaning weight response of pigs to simple and complex diets

Five experiments were conducted to determine (1) the value of simple vs complex diets on gains and feed conversion of pigs weaned at a constant age but varying in weight, (2) the optimum postweaning time to change from a complex to a simple diet and (3) the effect of previous treatment on subsequent performance. In the first experiment, pigs were weaned at 3 wk +/- 3 d and assigned within four weight groups (4.1, 5.0, 5.6 and 6.7 kg) to a simple or complex diet that was fed for 28 d. The complex diet improved (P less than .01) pig performance in all weight groups. As anticipated, the heavier pigs (5.6 and 6.7 kg) ate more (P less than .02) and grew faster (P less than .03) than did their lighter weight littermates (4.1 and 5.0 kg). The second experiment involved pigs weaned at 3 wk +/- 3 d that were assigned within two weight groups (4.4 and 6.6 kg) and fed a complex diet for 10 d, after which one-half of each weight group was switched to a simple diet. Pigs fed the complex diet for the entire 24-d period gained faster (P less than .05) and were more efficient (P less than .05) than those changed to the simple diet after 10 d. The heavier weight (6.6 kg) pigs ate more (P less than .02) and gained faster (P less than .02) than did the lighter weight (4.4 kg) pigs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of vitamin E sources (RRR- or all-rac-alpha-tocopheryl acetate) and levels on sow reproductive performance, serum, tissue, and milk alpha-tocopherol contents over a five-parity period, and the effects on the progeny

Two dietary sources of vitamin E (DL-alpha-tocopheryl acetate [DL-beta-TAc], or D-alpha-tocopheryl acetate [DL-alpha-TAc]) at two dietary supplemental levels (30 vs 60 IU/kg) were evaluated in reproducing sows over a five-parity period. The experiment was a 2 x 2 factorial arrangement of treatments conducted as a randomized complete block in two replicates. A total of 48 gilts were fed their treatment diets from 40 kg BW through five parities, reflecting a total of 171 farrowings. Reproductive measurements of litter size, sow weight, and back-fat thickness were collected. The incidence of mastitis-metritis-agalactia (MMA) and fluid discharge from the vagina were evaluated for each sow on each of the first 3 d postpartum. Sows were bled at periodic intervals during gestation and at weaning (21 d) and serum was frozen. After the fifth parity, two to four sows from each treatment group were killed and tissues collected. At birth, two to three neonatal pigs were killed from each sow treatment group within each parity and livers were collected and frozen. In addition, three pigs from each litter from three to four sows per treatment group within each parity were bled at weaning and serum was saved. Six pigs from each sow group at weaning of Parity 5 were also killed and livers were collected and frozen. Sow and pig sera and tissues were analyzed for a-tocopherol. There was no effect (P > .15) of vitamin E source or level on the various sow reproductive measurements, litter size, or the incidences of MMA or fluid discharges from the vagina. Feeding D-alpha-TAc compared with DL-alpha-TAc or 60 IU compared with 30 IU vitamin E/kg diet resulted in higher (P < .01) sow serum, colostrum, and milk alpha-tocopherol contents at each measurement period. Sow liver, adipose, lung, and heart alpha-tocopherol contents were also higher (P < .01) when the 60 IU vitamin E level had been fed. Both serum and liver a-tocopherol contents in 21-d-old nursing pigs were higher (P < .01) when the sow had been fed D-alpha-TAc compared with the DL-alpha-TAc source or when the 60 IU level had been fed. There were no vitamin E source x vitamin E level interactions (P > .15) for the various alpha-tocopherol measurements. Although the supplemental vitamin E sources were provided on an equivalent IU basis, these results suggest that D-alpha-TAc has a higher equivalency than DL-alpha-TAc on an IU basis, but higher dietary levels also resulted in higher sow and pig alpha-tocopherol contents.     

The effects of dietary energy concentration and weaning site on weanling pig performance

This study was conducted to evaluate the effects of dietary energy density and weaning environment on pig performance. Treatment diets were formulated to vary in DE concentration by changing the relative proportions of low (barley) and high (wheat, oat groats, and canola oil) energy ingredients. In Exp. 1, 84 pigs in each of 3 replications, providing a total of 252 pigs, were weaned at 17 x 2 d of age and randomly assigned to either an on-site or an off-site nursery and to 1 of 3 dietary DE concentrations (3.35, 3.50, or 3.65 Mcal/kg). Each site consisted of a nursery containing 6 pens; 3 pens housed 7 barrows and 3 housed 7 gilts. All pigs received nontreatment diets in phase I (17 to 19 d of age) and phase II (20 to 25 d of age), respectively. Dietary treatments were fed from 25 to 56 d of age. Off-site pigs were heavier at 56 d of age (23.4 vs. 21.3 kg; P < 0.05) and had greater ADFI (0.77 vs. 0.69 kg/d; P < 0.01) than on-site pigs. There was a linear decrease in ADG (P < 0.01) and ADFI (P < 0.001) with increasing DE concentration. Efficiency of gain improved (P < 0.01) with increasing DE concentration. There was no interaction between weaning site and diet DE concentration, indicating that on-site and off-site pigs responded similarly to changes in diet DE concentration. In Exp. 2, nutrient digestibility of the treatment diets used in Exp. 1 was determined using 36 pigs with either ad libitum or feed intake restricted to 5.5% of BW. Energy and N digestibility increased (P < 0.001) with increasing DE concentration. Nitrogen retention and daily DE intake increased with DE concentration in pigs fed the restricted amount of feed (P < 0.05). These results indicate that weaning off-site improves pig weight gain. The weanling pig was able to compensate for reduced dietary DE concentration through increased feed intake. Growth limitation in the weanling pig may not be overcome simply by increasing dietary DE concentration.     

Early- and traditionally weaned nursery pigs benefit from phase-feeding pharmacological concentrations of zinc oxide: effect on metallothionein and mineral concentrations.

Benefits of feeding pharmacological concentrations of zinc (Zn) provided by Zn oxide (ZnO) to 21-d conventionally weaned pigs in the nursery have been documented; however, several management questions remain. We conducted two experiments to evaluate the effect on growth from feeding 3,000 ppm Zn as ZnO during different weeks of the nursery period. In Exp. 1 (n = 138, 11.5 d of age, 3.8 kg BW) and Exp. 2 (n = 246, 24.5 d of age, 7.2 kg BW), pigs were fed either basal diets containing 100 ppm supplemental Zn (adequate) or the same diet with an additional 3,000 ppm Zn (high) supplied as ZnO. Pigs were fed four or two dietary phases in Exp. 1 and 2, respectively, that changed in dietary ingredients and nutrient content (lysine and crude protein) to meet the changing physiological needs of the pigs for the 28-d nursery period. Dietary Zn treatments were 1) adequate Zn fed wk 1 to 4, 2) high Zn fed wk 1, 3) high Zn fed wk 2, 4) high Zn fed wk 1 and 2, 5) high Zn fed wk 2 and 3, and 6) high Zn fed wk 1 to 4. In Exp. 1 and 2, pigs fed high Zn for wk 1 and 2 or the entire 28-d nursery period had the greatest (P < .05) ADG. During any week, pigs fed high Zn had greater concentrations of hepatic metallothionein and Zn in plasma, liver, and kidney than those pigs fed adequate Zn (P < .05). In summary, both early- and traditionally weaned pigs need to be fed pharmacological concentrations of Zn provided as ZnO for a minimum of 2 wk immediately after weaning to enhance growth.     

Evaluating the antioxidant status of weanling pigs fed dietary vitamins A and E

Two experiments evaluated the relationship of vitamin E (source and level) and vitamin A (level) on the apparent absorption and retention of both vitamins in weaned pigs. Both experiments used a combined total of 460 crossbred pigs ([Yorkshire x Landrace] x Duroc), housed in elevated 1.2- x 1.2-m crates containing five pigs per pen. Experiment 1 was a 2 x 2 x 2 factorial arrangement of treatments in a randomized complete block design conducted in seven replicates. Levels of vitamin A (2,200 or 13,200 IU/kg), vitamin E (15 or 90 IU/kg), and two vitamin E sources (D-alpha-tocopheryl acetate [D-TAc] or DL-alpha-tocopheryl acetate [DL-TAc]) were evaluated over a 35-d period. Vitamin A or E levels and the two vitamin E sources did not affect pig performances to 20 kg BW. Serum retinol and alpha-tocopherol concentrations increased (P < 0.01) as the dietary level of each vitamin increased. Serum alpha-tocopherol declined as dietary vitamin E level increased when vitamin A level increased resulting in an interaction (P < 0.05). Serum alpha-tocopherol concentrations were higher (P < 0.05) at 35-d postweaning when D-TAc was the vitamin E source. Experiment 2 was a 3 x 2 factorial arrangement of treatments conducted in six replicates. Three levels of vitamin A (2,200, 13,200, or 26,400 IU/ kg) and two sources of vitamin E (D-TAc or DL-TAc) each provided at 40 IU/kg diet were evaluated over a 35-d period. Pig performances to 35-d postweaning were not affected by the dietary variables. Serum alpha-tocopherol (P < 0.01) and retinol (P < 0.05) concentrations increased as their respective vitamin level increased. Serum (P < 0.05) and liver (P < 0.01) alpha-tocopherol concentrations both declined as dietary vitamin A levels increased resulting in interaction responses. Serum alpha-tocopherol concentration was higher (P < 0.05) at 35-d postweaning when d-TAc was the vitamin E source. Dietary vitamin E sources had no effect on serum or liver retinol concentrations. These results demonstrated that both supplemental vitamin A and vitamin E increased in the blood as their dietary levels increased. However, as dietary vitamin A level increased, serum and liver alpha-tocopherol concentrations declined, suggesting a reduced absorption and retention of alpha-tocopherol when weaned pigs were fed high dietary vitamin A levels.     

Effect of fumaric acid and dietary buffering capacity on ileal and fecal amino acid digestibilities in early-weaned pigs

Experiments were conducted to determine the effect of fumaric acid supplementation and buffering capacity of the diet on ileal and fecal digestibilities of CP, GE, and amino acids in early-weaned pigs. In two experiments, 12 pigs each were weaned at 14 d of age and fitted with a simple T-cannula at the distal ileum between 15 and 17 d of age. In both experiments, the pigs were fed four diets, based on wheat and soybean meal without (control) or with 1, 2, or 3% fumaric acid according to a balanced two-period change-over design. In Exp. 2, the buffering capacity of the diets was increased by supplementation of 3% sodium bicarbonate. The pigs were fed three times daily: equal amounts at 8-h intervals. The diets were supplied at a rate of 5% (wt/wt) of body weight. The inclusion of fumaric acid to the diet with a low buffering capacity increased (P < .05) the ileal digestibilities of CP, GE, and the majority of amino acids. The highest responses were found at an inclusion level of 2% fumaric acid. The improvements in apparent ileal amino acid digestibilities ranged from 4.9 to 12.8 percentage units. Supplementation of fumaric acid to a diet with a high buffering capacity led only to numerical increases in ileal digestibilities of CP, GE, and amino acids. In both studies, fumaric acid supplementation had no effect (P > .05) on the fecal digestibilities of CP, GE, and amino acids, except histidine. A high buffering capacity of the diet decreased the ileal amino acid digestibilities by 1 to 10 percentage units compared with diets with the low buffering capacities. In both experiments, ileal and fecal digestibilities were higher (P < .05) in Period 2 (on d 24 after weaning) than in Period 1 (on d 11 after weaning). A positive correlation (P < .05) between ileal digestibilities and fumaric acid supplementation to the diets with the low buffering capacities was observed in Period 1 (on d 11 after weaning), but not in Period 2 (on d 24 after weaning). No relationship (P > .05) between ileal digestibilities and fumaric acid supplementation to the diets with a high buffering capacity could be established. In conclusion, supplementation of fumaric acid to starter diets during the first 3 to 4 wk after weaning increases the ileal digestibilities of GE, CP, and amino acids.     

Effects of vitamin C supplementation on performance, iron status and immune function of weaned piglets.

Two experiments were conducted to evaluate the effects of vitamin C supplementation on performance, iron status and immune function of pigs during the 21-day post-weaning period. In experiment one, 48 crossbred pigs (Chester White x Large White x Yorkshire), weaned at 30 days of age and weighing 7.7 +/- 0.9 kg, were allotted to diets containing either 0 or 300 mg/kg vitamin C. In experiment two, 96 crossbred pigs (Chester White x Large White x Yorkshire), weaned at 20 +/- 2 days and weighing 7.1 +/- 0.5 kg, were allotted to diets containing 0.75 or 300 mg/kg vitamin C. Six replicate pens were assigned to each treatment in experiment one while experiment two had eight replicates. All pens housed two barrows and two gilts. In both experiments, no improvement (P > 0.05) in growth rate, feed intake or feed conversion was observed as a result of vitamin C supplementation. Plasma iron concentration increased (P < 0.10) with increased vitamin C in the diet while free and total iron binding capacity were unaffected by treatment. There were no differences in the intradermal response to the mitogen phytohemaggutinin used as an indicator of cellular immunity (P > 0.05). In trial 2, the plasma levels of the immunoglobulin IgG showed a linear (P = 0.07) increase with increasing levels of vitamin C and the same trend was noted in trial 1. Antibody titers to bovine serum albumin also tended to increase in both trials but the increases were not statistically significant. In conclusion, the overall results of these experiments indicate that weanling pig performance is not improved as a result of vitamin C supplementation. Whether or not vitamin C plays a role in stimulating humoral immune function in pigs requires further study since the results of our experiments do not completely rule out the possibility that such a role exists.     

Exocrine pancreatic secretion in pigs fed sow's milk and milk replacer, and its relationship to growth performance

The objective of this study was to quantify and compare the effects of sow's milk and 2 milk replacer diets (containing clotting or non-clotting protein sources) on exocrine pancreatic secretion, plasma cholecystokinin, and immunoreactive cationic trypsin in pigs. In addition, the relationship between exocrine pancreatic secretion and growth in milk-fed pigs was studied. In a changeover experiment, 9 chronically catheterized pigs of 6.6 +/- 0.19 kg of BW were studied for 3 wk. Pigs were assigned to each of 3 diets. Exocrine pancreatic secretion was measured from the third to the seventh day on each diet. The protein content and trypsin activity of the pancreatic juice were measured. Blood samples were taken at 10 min before and after milk ingestion and were analyzed for cholecystokinin and immunoreactive cationic trypsin. Pancreatic protein and trypsin secretion did not differ between pigs fed sow's milk and those fed milk replacer, but the volume secreted was less for the pigs fed sow's milk (0.75 vs. 1.03 mL x kg(-1) x h(-1); P < 0.01). A postprandial response to milk intake was not observed. The 2 milk replacer diets did not affect exocrine pancreatic secretion differently. The average exocrine pancreatic secretion (volume, 0.94 mL x kg(-1) x h(-1); protein, 4.28 mg x kg(-1) x h(-1); trypsin, 1.65 U x kg(-1) x h(-1)) was intermediate between literature values for suckling and weaned pigs. Plasma cholecystokinin was elevated (approximately 18 pmol x L(-1)) and showed low correlations with the pancreatic secretion traits. Plasma immunoreactive cationic trypsin was not significantly related to any of the pancreatic secretion traits and should therefore not be used as an indicator for exocrine pancreatic function in milk-fed pigs. Exocrine pancreatic secretion varied substantially among individual pigs (protein, 0.22 to 13.98 mg x kg(-1) x h(-1)). Pancreatic protein and trypsin secretion showed a positive, nonlinear relationship with performance traits. It was concluded that neither specific sow's milk ingredients nor the protein source are responsible for a low pancreatic protein secretion in suckling pigs. Exocrine pancreatic secretion was positively correlated with ADG in pigs at an identical milk intake.     

Optimal dietary concentration of vitamin E for alleviating the effect of heat stress on egg production in laying hens.

1. The effects of different dietary concentrations of vitamin E (alpha-tocopherol acetate) were investigated on laying hens exposed to chronic heat stress at 32 degrees C from 26 to 30 weeks of age. 2. Diets containing 5 dietary concentrations of vitamin E (a control diet containing 10 mg alpha-tocopherol/kg or this diet supplemented to contain 125, 250, 375 and 500 mg alpha-tocopherol/kg) were fed to 335 birds. Half of the birds received the supplemented diets for only 4 weeks before the heat stress period (short supplementation duration, SSD) and were fed on the control diet for a further 12 weeks. The remaining birds were fed on the supplemented diets throughout the experiment, 4 weeks before, 4 weeks during and 8 weeks after the heat stress period (long supplementation duration, LSD). 3. Egg production was significantly higher during (80-6 vs 68.9%, P<0.02) and after (75.3 vs 62.7%, P<0.02) the period of stress in the LSD group fed on the diet containing 250 mg vitamin E/kg compared with the group fed on the control diet. LSD birds given 375 and 500 mg vitamin E/kg also had higher egg production than control birds during heat stress but the differences failed to reach significance (74.6 vs 68.9% and 77.1 vs 68.9% respectively). In the SSD groups, mean egg production of the birds given the diets supplemented with 125 mg vitamin E/kg or more was significantly different from the control group after heat stress (70.3 vs 62.7%, P<0.05). Egg weight and food intake were similar in all the groups. 4. Plasma and liver vitamin E concentrations were proportional to the vitamin E intake before the stress period, dropped during heat stress in the SSD groups but were maintained at concentrations closer to those observed before heat stress in the LSD groups. 5. It is concluded that a dietary supplement of 250 mg vitamin E/kg provided before, during and after heat stress is optimum for alleviating, at least in part, the adverse effects of chronic heat stress in laying hens.