Evaluation of various inclusion rates of organic zinc either as polysaccharide or proteinate complex on the growth performance, plasma, and excretion of nursery pigs

Three experiments were conducted to evaluate the effects of feeding dietary concentrations of organic Zn as a Zn-polysaccharide (Quali Tech Inc., Chaska, MN) or as a Zn-proteinate (Alltech Inc., Nicholasville, KY) on growth performance, plasma concentrations, and excretion in nursery pigs compared with pigs fed 2,000 ppm inorganic Zn as ZnO. Experiments 1 and 2 were growth experiments, and Exp. 3 was a balance experiment, and they used 306, 98, and 20 crossbred pigs, respectively. Initially, pigs averaged 17 d of age and 5.2 kg BW in Exp. 1 and 2, and 31 d of age and 11.2 kg BW in Exp. 3. The basal diets for Exp. 1, 2, and 3 contained 165 ppm supplemental Zn as ZnSO4 (as-fed basis), which was supplied from the premix. In Exp. 1, the Phase 1 (d 1 to 14) basal diet was supplemented with 0, 125, 250, 375, or 500 ppm Zn as Zn-polysaccharide (as-fed basis) or 2,000 ppm Zn as ZnO (as-fed basis). All pigs were then fed the same Phase 2 (d 15 to 28) and Phase 3 (d 29 to 42) diets. In Exp. 2, both the Phase 1 and 2 basal diets were supplemented with 0, 50, 100, 200, 400, or 800 ppm Zn as Zn-proteinate (as-fed basis) or 2,000 ppm Zn as ZnO (as-fed basis). For the 28-d Exp. 3, the Phase 2 basal diet was supplemented with 0, 200, or 400 ppm Zn as Zn-proteinate, or 2,000 ppm Zn as ZnO (as-fed basis). All diets were fed in meal form. In Exp. 1, 2, and 3, pigs were bled on d 14, 28, or 27, respectively, to determine plasma Zn and Cu concentrations. For all three experiments, there were no overall treatment differences in ADG, ADFI, or G:F (P = 0.15, 0.22, and 0.45, respectively). However, during wk 1 of Exp. 1, pigs fed 2,000 ppm Zn as ZnO had greater (P < or = 0.05) ADG and G:F than pigs fed the basal diet. In all experiments, pigs fed a diet containing 2,000 ppm Zn as ZnO had higher plasma Zn concentrations (P < 0.10) than pigs fed the basal diet. In Exp. 1 and 3, pigs fed 2,000 ppm Zn as ZnO had higher fecal Zn concentrations (P < 0.01) than pigs fed the other dietary Zn treatments. In conclusion, organic Zn either as a polysaccharide or a proteinate had no effect on growth performance at lower inclusion rates; however, feeding lower concentrations of organic Zn greatly decreased the amount of Zn excreted.     

Effect of microbial phytase addition with or without the trace mineral premix in nursery, growing, and finishing pig diets

Two experiments were conducted to determine the interactive effects of phytase with and without a trace mineral premix (TMP) in diets for nursery, growing, and finishing pigs on growth performance, bone responses, and tissue mineral concentrations. Pigs (initial and final BW of 5.5 and 111.6 kg [Exp. 1] or 5.4 and 22.6 kg [Exp. 2]) were allotted to treatments on the basis of BW with eight (Exp. 1) or six (Exp. 2) replications of six or seven pigs per replicate pen. Pigs were started on the diets the day of weaning (average of 18 d). In both experiments, the treatments were with or without 500 phytase units/kg of diet and with or without the TMP in a 2 x 2 factorial arrangement. The Ca and available P concentrations were decreased by 0.10% in diets with phytase. The nursery phase consisted of Phase I (7 d), Phase II (14 d), and Phase III (13 d) periods. In Exp. 1, 26 of 52 pigs fed the diet without the TMP and without phytase had severe skin lesions and decreased growth performance; therefore, pigs fed this diet were switched to the positive control diet. In Exp. 2, the treatment without the TMP and without phytase had 12 replications instead of six. At the end of Phase III, half these replications were switched to the positive control diet and half were switched to the diet without the TMP but with phytase. In Exp. 1 during Phases II and III and in the overall data, pigs fed the diet without the TMP had decreased ADG and ADFI, but the addition of phytase prevented these responses (phytase x TMP; P < 0.02). Growth performance was not affected by diet during the growing-finishing period. Coccygeal bone Zn and Na concentrations were decreased (P < 0.09) in pigs fed the diet without the TMP, and adding phytase increased (P < 0.03) Zn and Fe concentrations. In Exp. 2 during Phases I and II, pigs fed the diet without the TMP had decreased ADG, but the addition of phytase prevented this response (phytase x TMP; P < 0.10). Pigs fed the diet without the TMP had decreased (P < 0.10) ADG (Phase II and overall), ADFI (Phases II and III and in the overall data), and G:F (Phase III). Coccygeal bone Zn and Cu concentrations were decreased (P < 0.09) in pigs fed the diet without the TMP, and adding phytase increased (P < 0.03) Zn concentration in the bones. These data indicate that removing the TMP in diets for nursery pigs decreases growth performance and bone mineral content, and that phytase addition to the diet without the TMP prevented the decreased growth performance.     

Effects of dietary iron supplementation on growth performance, hematological status, and whole-body mineral concentrations of nursery pigs

An experiment was conducted to evaluate the effects of supplementing increasing concentrations of Fe to the diet of nursery pigs on growth performance and indices of hematological and mineral status. Pigs (n = 225; 6.5 kg; 19 +/- 3 d) were allotted randomly by BW, litter, and gender to one of five dietary treatments (five pigs per pen; nine pens per treatment). Basal diets for each phase (Phase 1: d 0 to 7; Phase 2: d 7 to 21; Phase 3: d 21 to 35) were formulated to contain minimal Fe concentration and then supplemented with 0, 25, 50, 100, and 150 mg Fe/kg of diet (as-fed basis) from ferrous sulfate. Three pigs per pen (n = 135) were chosen and bled throughout (d 0, 7, 21, and 35) to determine hemoglobin (Hb), hematocrit (Hct), transferrin (Tf), and plasma Fe (PFe). In addition, pigs (n = 5; 5.9 kg; 19 +/- 3 d) from the contemporary group were killed at d 0 to establish baseline (BL), and 30 pigs (six pigs/treatment) were killed at d 35 to determine whole-body and liver mineral concentrations. The improvements in growth performance during Phase 2 (ADG = linear, P = 0.04; ADFI = linear, P = 0.10; G:F = quadratic, P = 0.07) were of sufficient magnitude that dietary treatments tended to increase ADG (linear, P = 0.08), ADFI (quadratic, P = 0.09), and G:F (quadratic, P = 0.10) for the 35-d experiment. Hematological variables were not affected until d 21, at which time dietary Fe supplementation resulted in a linear increase (P = 0.03) in Hb, Hct, and PFe. This linear increase (P = 0.001) was maintained until d 35 of the experiment; however, dietary treatments resulted in a linear decrease (P = 0.01) in Tf on d 35. Whole-body Fe concentration increased (linear, P = 0.01) in pigs due to increasing dietary Fe concentrations. Moreover, pigs fed for 35 d had greater (P = 0.02) whole-body Fe, Zn, Mg, Mn, Ca, and P concentrations and lower (P = 0.001) whole-body Cu concentration than BL. Hepatic Fe concentration increased (linear, P = 0.001) in pigs due to dietary treatments; however, the hepatic Fe concentration of all pigs killed on d 35 was lower (P = 0.001) than the BL. Results suggest that Fe contributed by feed ingredients was not sufficient to maintain indices of Fe status. The decrease in Fe stores of the pigs was not severe enough to reduce growth performance. Even so, the lessening of a pig's Fe stores during this rapid growth period may result in the occurrence of anemia during the subsequent grower and finisher periods.     

Effect of feeding organic and inorganic sources of additional zinc on growth performance and zinc balance in nursery pigs

Three experiments were conducted to evaluate the effect of feeding pharmacological concentrations of zinc (Zn), from organic and inorganic sources, on growth performance, plasma and tissue Zn accumulation, and Zn excretion of nursery pigs. Blood from all pigs was collected for plasma Zn determination on d 14 in Exp. 1, d 7 and 28 in Exp. 2, and d 15 in Exp. 3. In Exp. 1, 2, and 3, 90, 100, and 15 crossbred (GenetiPorc USA, LLC, Morris, MN) pigs were weaned at 24+/-0.5, 18, and 17 d of age (6.45, 5.47, and 5.3 kg avg initial BW), respectively, and allotted to dietary treatment based on initial weight, sex, and litter. A Phase 1 nursery diet was fed as crumbles from d 0 to 14 in Exp. 1, 2, and 3, and a Phase 2 nursery diet was fed as pellets from d 15 to 28 in Exp. 1 and 2. The Phase 1 and Phase 2 basal diets were supplemented with 100 ppm Zn as ZnSO4. Both dietary phases contained the same five dietary treatments: 150 ppm additional Zn as zinc oxide (ZnO), 500 ppm added Zn as ZnO, 500 ppm added Zn as a Zn-amino acid complex (Availa-Zn 100), 500 ppm added Zn as a Zn-polysaccharide complex (SQM-Zn), and 3,000 ppm added Zn as ZnO. Overall in Exp. 1, pigs fed 500 ppm added Zn as SQM-Zn or 3,000 ppm added Zn as ZnO had greater ADG (P < 0.05) than pigs fed 150 ppm, 500 ppm added Zn as ZnO, or 500 ppm added Zn as Availa-Zn 100 (0.44 and 0.46 kg/d vs 0.35, 0.38, and 0.33 kg/d respectively). Overall in Exp. 2, pigs fed 3,000 ppm added Zn as ZnO had greater (P < 0.05) ADG and ADFI than pigs fed any other dietary treatment. On d 14 of Exp. 1 and d 28 of Exp. 2, pigs fed 3,000 ppm added Zn as ZnO had higher (P < 0.05) plasma Zn concentrations than pigs on any other treatment. In Exp. 3, fecal, urinary, and liver Zn concentrations were greatest (P < 0.05) in pigs fed 3,000 ppm added Zn as ZnO. On d 10 to 15 of Exp. 3, pigs fed 3,000 ppm added Zn as ZnO had the most negative Zn balance (P < 0.05) compared with pigs fed the other four dietary Zn treatments. In conclusion, feeding 3,000 ppm added Zn as ZnO improves nursery pig performance; however, under certain nursery conditions the use of 500 ppm added Zn as SQM-Zn may also enhance performance. The major factor affecting nutrient excretion appears to be dietary concentration, independent of source.     

Effects of supplemental dietary phytase and pharmacological concentrations of zinc on growth performance and tissue zinc concentrations of weanling pigs

Three experiments were conducted to determine the effects of phytase, excess Zn, or their combination in diets for nursery pigs. In all experiments, treatments were replicated with five to seven pens of six to seven pigs per pen, dietary Ca and available P (aP) levels were decreased by 0.1% when phytase was added to the diets, excess Zn was added as ZnO, a basal level of 127 mg/kg of Zn (Zn sulfate) was present in all diets, and the experimental periods were 19 to 21 d. In Exp. 1, pigs (5.7 kg and 18 d of age) were fed two levels of phytase (0 or 500 phytase units/kg) and three levels of excess Zn (0, 1,000, or 2,000 ppm) in a 2 x 3 factorial arrangement. Added Zn linearly increased ADG and ADFI during Phase 1 (P = 0.01 to 0.06), Phase 2 (P = 0.02 to 0.09), and overall (P = 0.01 to 0.02). Gain:feed was linearly increased by Zn during Phase 1 (P = 0.01) but not at other times. Dietary phytase decreased ADG in pigs fed 1,000 or 2,000 ppm Zn during Phase 2 (Zn linear x phytase interaction; P = 0.10), did not affect (P = 0.27 to 0.62) ADFI during any period, and decreased G:F during Phase 2 (P = 0.01) and for the overall (P = 0.07) period. Plasma Zn was increased by supplemental Zn (Zn quadratic, P = 0.01) but not affected (P = 0.70) by phytase addition. In Exp. 2, pigs (5.2 kg and 18 d of age) were fed two levels of phytase (0 or 500 phytase units/kg) and two levels of Zn (0 or 2,000 ppm) in a 2 x 2 factorial arrangement. Supplemental Zn increased ADG and G:F during Phase 2 (P = 0.02 to 0.09) and overall (P = 0.07 to 0.08), but it had no effect (P = 0.11 to 0.89) on ADG during Phase 1 or ADFI during any period. Phytase supplementation increased ADG (P = 0.06) and G:F (P = 0.01) during Phase 2. Gain:feed was greatest for pigs fed 2,000 ppm Zn and phytase (Zn x phytase interaction; P = 0.01). Bone (d 20) and plasma Zn (d 7 and 20) were increased (P = 0.01) by added Zn but not affected (P = 0.51 to 0.90) by phytase. In Exp. 3, pigs (5.7 kg and 19 d of age) were fed a basal diet or the basal diet with Ca and aP levels decreased by 0.10% and these two diets with or without 500 phytase units/kg. Supplemental phytase had no effect (P = 0.21 to 0.81) on growth performance. Reduction of dietary Ca and aP decreased (P = 0.02 to 0.08) ADG, ADFI, and G:F for the overall data. These results indicate that excess dietary supplemental Zn increases ADG and plasma and bone Zn concentrations. Dietary phytase did not affect plasma or bone Zn concentrations.     

Effects of water and diet acidification with and without antibiotics on weanling pig growth and microbial shedding

Two 5-wk experiments were conducted to determine the effects of water and diet acidification with and without antibiotics on weanling pig growth performance and microbial shedding. In Exp. 1, 204 pigs (19.2 d of age) were used in a 3 x 2 factorial, with 3 dietary treatments fed with or without water acidification (2.58 mL/L of a propionic acid blend; KEM SAN, Kemin Americas, Des Moines, IA). Dietary treatments were: 1) control, 2) control + 55 ppm of carbadox (CB), and 3) dietary acid [DA; control + 0.4% organic acid-based blend (fumaric, lactate, citric, propionic, and benzoic acids; Kemin Americas)] on d 0 to 7 followed by 0.2% inorganic acid-based blend (phosphoric, fumaric, lactic, and citric acids; Kemin Americas) on d 7 to 34. In Exp. 2, 210 pigs (average 18.3 d of age) were fed 1 of 3 dietary treatments: 1) control, 2) control + 55 ppm of CB, and 3) control + 38.6 ppm of tiamulin + 441 ppm of chlortetracycline on d 0 to 7 followed by 110 ppm of chlortetracycline on d 7 to 35 (TC) with or without dietary acidification (same as Exp. 1) in a 3 x 2 factorial arrangement of treatments. For both experiments, the pigs were allotted based on genetics, sex, and initial BW [5.5 kg (Exp. 1) or 5.6 kg (Exp. 2)]. Pigs were housed at 6 or 7 (Exp. 1) and 7 (Exp. 2) pigs/pen. Treatments were fed in 3 phases: d 0 to 7, 7 to 21, and 21 to 35 (34 d, Exp. 1). Fecal grab samples were collected from 3 pigs/pen on d 6, 20, and 33 for measurement of pH and Escherichia coli. During phase 3 and overall in Exp. 1, pigs fed CB had greater (P < 0.001) ADG (overall ADG, 389 vs. 348, and 348 g/d, respectively), ADFI (P < 0.007, 608 vs. 559, and 554 g/d, respectively), and d 34 BW (P < 0.001, 18.8 vs. 17.3, and 17.3 kg, respectively) than pigs fed NC and DA. Phase 3 ADG was improved (P < 0.01) by water acidification across all diets. In Exp. 2, pigs fed CB and TC had greater ADG (P < 0.004; 315 and 303 vs. 270 g/d, respectively), ADFI (P < 0.01), and d 35 BW (P < 0.002; 16.7 and 16.2 vs. 15.1 kg, respectively) than pigs fed NC. There was a tendency (P < 0.08) for an improvement in ADG when DA was added to the NC or TC, but decreased ADG when DA was added to CB.     

Effects of beta-mannanase addition to corn-soybean meal diets on growth performance,carcass traits,and nutrient digestibility of weanling and growing-finishing pigs

Four experiments were conducted to determine the effects of adding a beta-mannanase preparation (Hemicell, ChemGen, Gaithersburg, MD) to corn-soybean meal-based diets on growth performance and nutrient digestibility of weanling and growing-finishing pigs. In Exp. 1, 156 weanling pigs (20 d, 6.27 kg BW) were allotted to four dietary treatments in a randomized complete block design. Treatments were a factorial arrangement of diet complexity (complex vs simple) and addition of 3-mannanase preparation (0 vs 0.05%). Pigs were fed in three dietary phases (Phase 1, d 0 to 14; Phase 2, d 14 to 28; and Phase 3, d 28 to 42). Pigs fed complex diets gained faster and were more efficient (P < 0.05) during Phase 1 compared with pigs fed simple diets. Overall, gain:feed ratio (G:F) tended to be improved (P < 0.10) for pigs fed complex diets and it was improved (P < 0.01) for those fed diets with beta-mannanase. In Exp. 2, 117 pigs (44 d, 13.62 kg BW) were allotted randomly to three dietary treatments. Dietary treatments were 1) a corn-soybean meal-based control, 2) the control diet with soybean oil added to increase metabolizable energy (ME) by 100 kcal/kg, and 3) the control diet with 0.05% beta-mannanase preparation. Beta-mannanase or soybean oil improved (P < 0.05) G:F compared with pigs fed the control diet. In Exp. 3, 60 pigs (22.5 kg BW) were allotted randomly to the three dietary treatments used in Exp. 2. Dietary treatments were fed in three phases (23 to 53 kg, 53 to 82 kg, and 82 to 109 kg with 0.95, 0.80, and 0.65% lysine, respectively). Overall, the addition of soybean oil tended to improve G:F (P < 0.10) compared with that of pigs fed the control diet, and G:F was similar (P > 0.54) for pigs fed diets with soybean oil or beta-mannanase. Also, addition of beta-mannanase increased ADG (P < 0.05) compared with that of pigs fed the control or soybean oil diets. There were no differences (P > or = 0.10) in longissimus muscle area or backfat; however, on a fat-free basis, pigs fed the diet with beta-mannanase had greater (P < 0.05) lean gain than pigs fed the control or soybean oil diets. In Exp. 4, 12 barrows (93 kg BW) were allotted randomly to one of the three dietary treatments used in Exp. 3. Addition of 3-mannanase had no effect (P > 0.10) on energy, nitrogen, phosphorus, or dry matter digestibility. These results suggest that beta-mannanase may improve growth performance in weanling and growing-finishing pigs but has minimal effects on nutrient digestibility.     

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.     

Comparison of growth performance and zinc absorption, retention, and excretion in weanling pigs fed diets supplemented with zinc-polysaccharide or zinc oxide

Fifty weanling crossbred pigs averaging 6.2 kg of initial BW and 21 d of age were used in a 5-wk experiment to evaluate lower dietary concentrations of an organic source of Zn as a Zn-polysaccharide (Zn-PS) compared with 2,000 ppm of inorganic Zn as ZnO, with growth performance, plasma concentrations of Zn and Cu, and Zn and Cu balance as the criteria. The pigs were fed individually in metabolism crates, and Zn and Cu balance were measured on individual pigs (10 replications per treatment) from d 22 to 26. The basal Phase 1 (d 0 to 14) and Phase 2 (d 14 to 35) diets contained 125 or 100 ppm added Zn as Zn sulfate, respectively, and met all nutrient requirements. Treatments were the basal Phase 1 and 2 diets supplemented with 0, 150, 300, or 450 ppm of Zn as Zn-PS or 2,000 ppm Zn as ZnO. Blood samples were collected from all pigs on d 7, 14, and 28. For pigs fed increasing Zn as Zn-PS, there were no linear or quadratic responses (P > or = 0.16) in ADG, ADFI, or G:F for Phases 1 or 2 or overall. For single degree of freedom treatment comparisons, Phase 1 ADG and G:F were greater (P < or = 0.05) for pigs fed 2,000 ppm Zn as ZnO than for pigs fed the control diet or the diet containing 150 ppm Zn as Zn-PS. For Phase 2 and overall, ADG and G:F for pigs fed the diets containing 300 or 450 ppm of Zn as Zn-PS did not differ (P > or = 0.29) from pigs fed the diet containing ZnO. Pigs fed the diet containing ZnO also had a greater Phase 2 (P < or = 0.10) and overall (P < or = 0.05) ADG and G:F than pigs fed the control diet. There were no differences (P > or = 0.46) in ADFI for any planned comparison. There were linear increases (P < 0.001) in the Zn excreted (mg/d) with increasing dietary Zn-PS. Pigs fed the diet containing ZnO absorbed, retained, and excreted more Zn (P < 0.001) than pigs fed the control diet or any of the diets containing Zn-PS. In conclusion, Phase 2 and overall growth performance by pigs fed diets containing 300 or 450 ppm Zn as Zn-PS did not differ from that of pigs fed 2,000 ppm Zn as ZnO; however, feeding 300 ppm Zn as Zn-PS decreased Zn excretion by 76% compared with feeding 2,000 ppm Zn as ZnO.     

Impact of vitamin and mineral supplement withdrawal and wheat middling inclusion on finishing pig growth performance,fecal mineral concentration,carcass characteristics,and the nutrient content and oxidative stability of pork

A study was conducted to determine if supplement withdrawal (omission of dietary vitamin and trace mineral premixes and a two-thirds reduction in dietary inorganic phosphorus) for 28 d preslaughter and the feeding of wheat middlings (dietary concentrations of 5, 15, and 30% from weaning to 16, 16 to 28, and 28 kg to slaughter, respectively) affect growth performance, carcass characteristics, and fecal mineral concentrations ofthe pig, as well as the nutrient content and oxidative stability of the longissimus dorsi muscle. Crossbred pigs (n = 64) were blocked by weight and assigned to one of four dietary treatments in a 2 x 2 factorial design (with or without supplement withdrawal, and with or without wheat middlings). Supplement withdrawal and wheat middling inclusion did not influence average daily gain (ADG), average daily feed intake, gain/feed, or carcass traits, except for a decrease (P < 0.01) in the ADG of pigs from 28 to 65 kg when fed wheat middlings. Supplement withdrawal decreased (P < 0.01) fecal Ca, P, Cu, Fe, Mn, and Zn concentrations. In diets containing full vitamin and mineral supplementation, wheat middling inclusion decreased (P < 0.01) fecal Ca, Cu, Fe, and Zn concentrations and increased (P < 0.01) fecal Mn. Supplement withdrawal decreased (P < 0.05) concentrations of riboflavin, niacin, and P in the longissimus dorsi muscle, but did not affect longissimus dorsi thiamin, vitamin E, Fe, Cu, Zn, and Ca concentrations. Inclusion of wheat middlings increased (P < 0.04) longissimus dorsi thiamin, niacin, riboflavin, and vitamin E concentrations and decreased (P < 0.04) Cu concentrations. However, wheat middling inclusion did not affect (P > 0.05) longissimus dorsi Ca, P, Fe, and Zn concentrations. Dietary treatment did not affect either Cu/Zn superoxide dismutase or glutathione peroxidase activity in the longissimus dorsi. The results from this study indicate that supplement withdrawal and dietary wheat middling inclusion alter pork nutrient content and fecal mineral concentration, but not the oxidative stability of pork.     

饲粮类型和肥育后期不添加维生素和微量矿物元素对猪生长性能、胴体和肌肉品质、粪中矿物元素排泄的影响

本研究共开展两个试验,探讨饲粮类型和不添加维生素和微量矿物元素对猪肥育后期生长性能、胴体和肌肉品质、粪中微量矿物元素排泄的影响。在试验1中,选用128头平均体重(78.5±4.6)kg的肥育猪,根据体重和性别分成4组,每组4圈(重复),每个重复8头猪。四组试验猪的试验处理为2×2因子设计,即两种类型(玉米-豆粕型和玉米-杂粕型)饲粮和添加或不添加维生素/微量矿物元素预混料。在试验2中,选用112头平均体重(90.3±6.3)kg的肥育猪,根据体重和性别分成4组,每组4圈(重复),每个重复7头猪。试验处理同试验1。结果显示,在79~110kg肥育期中(试验1),采食玉米-豆粕型饲粮的猪的增重速度和采食量显著高于采食玉米-杂粕型饲粮的猪(P<0.01或0.05)。在90~105kg肥育期中(试验2),采食玉米-豆粕型饲粮的猪的增重速度仍然高于采食玉米-杂粕型饲粮的猪(P<0.05)。但是,维生素和微量矿物元素添加与否对生长性能无显著影响(P>0.05)。饲粮类型和不添加维生素和微量矿物元素对胴体和肌肉品质均无显著影响(P>0.05)。粪中微量矿物元素含量不受饲粮类型的影响(P>0.05),但不添加维生素和微量矿物元素时,粪中铜、铁、锰的含量显著降低(P<0.01),粪中锌含量也有降低的趋势(P>0.05)。对于生长性能、胴体和肌肉品质以及微量矿物元素排泄量,饲粮类型×维生素/微量矿物元素预混料的交互作用不显著(P>0.05)。结果表明,在猪的肥育后期(最后约25~40d),在玉米-豆粕型和玉米-杂粕型饲粮中可不添加维生素和微量矿物元素,从而可降低饲料成本和减少微量矿物元素的排泄。     

Estimation of endogenous phosphorus loss in growing and finishing pigs fed semi-purified diets

Thirty-six barrows were used in a series of 3 P-balance experiments in which growing and finishing pigs were fed highly digestible, semi-purified diets at or below the dietary available P requirement to estimate the effect of BW on endogenous P loss. Experiments 1, 2, and 3 were conducted with pigs averaging 27, 59, and 98 kg of BW, respectively. In each experiment, pigs were placed in metabolism crates and allotted by weight and litter to 3 dietary treatments. The basal diet consisted of sucrose, dextrose, cornstarch, and casein fortified with minerals (except P) and vitamins. Diets 1, 2, and 3 in Exp. 1 were the basal diet with 0, 0.078, or 0.157% added P, respectively, from monosodium phosphate. In Exp. 2 and 3, diets 1, 2, and 3 were the basal diet with 0, 0.067, and 0.134% added P, respectively, from monosodium phosphate. Within replicate, pigs were fed equal amounts of feed twice daily. Pigs were adjusted to treatments for 7 d before a 6-d, marker-to-marker collection of feces and urine. Phosphorus intakes for pigs fed the 3 diets ranged from 1.73 to 3.91 g/d in Exp. 1, from 2.18 to 5.32 g/d in Exp. 2, and from 1.96 to 6.26 g/d in Exp. 3. Fecal P excretion and P absorption increased linearly (P < 0.05) with increasing P intake. In the 3 experiments, urinary P excretion (g/d) was low for pigs fed diet 1 (0.010, 0.011, 0.019) and diet 2 (0.013, 0.058, 0.084) and was low for pigs fed diet 3 in Exp. 1 (0.037); however, urinary P was greater in pigs fed diet 3 in Exp. 2 and 3 (0.550 and 0.486, respectively). When P absorption (Y, g/d) was regressed on P intake (X, g/d) in Exp. 1, 2, and 3, the relationships were linear (P < 0.01): Y = -0.110 + 0.971X (R2 = 0.999), Y = -0.156 + 0.939X (R2 = 0.998), and Y = -0.226 + 0.8919X (R2 = 0.982), respectively. Thus, our estimates of endogenous P loss at zero P intake were 110, 156, and 226 mg/d for 27-, 59-, and 98-kg pigs, respectively. When these Y-intercepts were regressed on BW, the relationship was Y = 63.06 + 1.632X (R2 = 0.996), where Y = endogenous P loss in mg/d and X = BW in kg. Based on these data, we estimate the endogenous P loss of pigs fed highly digestible, semi-purified diets to increase by approximately 1.632 mg for each 1-kg increase in BW from 25 to 100 kg.     

Effect of mannan oligosaccharides on growth performance of weanling pigs

Four experiments were conducted to evaluate the effects of mannan oligosaccharides (provided by Bio-Mos [BM], a product containing a minimum of 28% glucomannoprotein from S. cerevisiae) on growth performance of nursery pigs. Treatments were replicated with five to six pens of four to five pigs each. Initial BW ranged from 4.7 to 5.4 kg, and pigs were weaned at 16 to 20 d of age. Experiments 1, 2, and 4 consisted of Phase 1 (7 to 8 d), Phase 2 (12 to 14 d), and Phase 3 (7 to 8 d) periods, but Exp. 3 consisted only of Phase 1 (7 d) and 2 (14 d) periods. The diets for Phase 1, 2, and 3 contained 1.6, 1.5, and 1.1% Lys, respectively. The treatments in Exp. 1 were 0, 0.20, and 0.30% BM, which did not affect growth performance. The treatments in Exp. 2 were two levels of excess Zn (0 and 3,000 ppm) and three levels of BM (0, 0.20, and 0.30%) in a 2 x 3 factorial. Excess Zn increased (P < 0.08) ADG and ADFI in Phase 2 and 3 and overall. The 0.20% BM addition increased ADG (Phase 3 and overall) and ADFI (Phase 2 and overall) in the absence of excess Zn but did not affect or decreased these response variables in the presence of excess Zn (Zn x BM quadratic, P < 0.08). Experiment 3 was similar to Exp. 2, but the 0.30% BM addition was not used. Excess Zn decreased (P < 0.09) ADG in Phase 1 but increased (P < 0.09) ADG and ADFI in Phase 2. The BM decreased (P < 0.03) overall ADFI but increased Phase 2 and overall ADG and gain:feed (GF) in the absence of excess Zn but not in the presence of excess Zn (Zn x BM, P < 0.07). The BM decreased ADFI during Phase 2, but the decrease was greater in pigs fed excess Zn (Zn x BM, P < 0.07). Experiment 4 evaluated the interactive effects of the antibiotic (oxytetracycline and neomycin) and BM and of Zn and BM. Antibiotic (no excess Zn) increased (P < 0.01) ADG and ADFI in Phases 2 and 3 and overall. The BM addition decreased ADG and GF in Phase 2 when the antibiotic was not in the diet but increased ADG when the antibiotic was in the diet (antibiotic x BM, P < 0.05). Excess Zn increased (P < 0.07) ADG and ADFI during Phases 2 and 3 and overall. In Phase 2, the 0.20% BM decreased GF when excess Zn was not added to the diet but increased GF when Zn was included (Zn x BM, P < 0.03). Mannan oligosaccharides improved pig performance in some instances during Phase 2 when fed in combination with an antibiotic and no excess dietary Zn, but it had no effect or negative effects in the presence of excess Zn or in the absence of an antibiotic.     

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

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.     

Effects of Acid LAC and Kem-Gest acid blends on growth performance and microbial shedding in weanling pigs

Weanling pigs with mean initial BW of 6.04 kg (Exp.1) and 5.65 kg (Exp. 2) and mean age at weaning of 18.2 d (Exp. 1) and 17.7 d (Exp. 2) were used in two 5-wk experiments (Exp. 1, n = 180; Exp. 2, n = 300) to evaluate the effects of an organic acid blend (Acid LAC, Kemin Americas Inc., Des Moines, IA) and an inorganic/organic acid blend (Kem-Gest, Kemin Americas Inc.) on weanling pig growth performance and microbial shedding. In Exp. 1, the 5 dietary treatments were 1) negative control, 2) diet 1 + 55 ppm carbadox, 3) diet 1 + 0.4% Acid LAC, 4) diet 1 + 0.2% Kem-Gest, 5) diet 1 + 0.4% Acid LAC and 0.2% Kem-Gest. In Exp. 2, the 6 dietary treatments were diets 1 through 4 corresponding to Exp. 1, plus 5) sequence 1: 0.4% Acid LAC for 7 d followed by 0.2% Kem-Gest for 28 d, and 6) sequence 2: 0.2% Kem-Gest for 7 d followed by 0.4% Acid LAC for 28 d. Pigs were housed at 6 (Exp. 1) or 10 (Exp. 2) pigs/pen. Treatments were fed throughout the experiment in 3 phases: d 0 to 7, d 7 to 21, and d 21 to 35. In Exp. 1, there were no differences (P > 0.05) in ADG, ADFI, or G:F among the dietary treatments at any time during the study. In Exp. 2, throughout the study, pigs fed carbadox (diet 2) and sequence 1 (diet 5) diets had the greatest ADG (d 0 to 35; 262, 294, 257, 257, 292, and 261 g/d, diets 1 through 6, respectively; P < 0.05), greater ADFI than all other acid treatments (P < 0.05), and tended to have greater ADFI than diet 1 (P < 0.10). Fecal pH, Escherichia coli concentrations, and Salmonella presence were determined at d 6, 20, and 34 for Exp. 1, and on d 32 for Exp. 2. For both experiments, there was no effect of treatment on the presence of fecal Salmonella (P > 0.10) at any sampling time. In Exp. 1, fecal E. coli concentrations for pigs fed the carbadox (P < 0.05) diet were greater than for pigs fed the combination diet with 0.4% Acid LAC and 0.2% Kem-Gest on d 34, and the pigs fed the negative control diet tended (P < 0.10) to have greater fecal E. coli concentrations than those fed the combination diet on d 34. In Exp. 2, fecal pH of pigs fed sequence 1 tended to be greater than fecal pH of pigs fed diet 1, diet 4, or sequence 2 (P < 0.10), but there was no dietary effect on fecal E. coli. In Exp. 1, growth performance of pigs fed the Acid LAC and Kem-Gest diets was similar to each other and to that of the carbadox-fed pigs. Adding the combination of 0.4% Acid LAC and 0.2% Kem-Gest to nursery pig diets reduced ADFI and pig growth rate. In Exp. 2, pigs fed the acid sequence of Acid LAC-Kem-Gest had similar growth performance to pigs fed carbadox, and this novel dietary acid sequence may have merit as a replacement for antibiotics in the nursery phase.     

Effect of dietary trace mineral concentration and source (inorganic vs. chelated) on performance, mineral status, and fecal mineral excretion in pigs from weaning through finishing

Two hundred and sixteen weanling gilts (6.65+/-0.08 kg) were used to determine the effects of decreasing supplemental concentrations of Zn, Cu, Fe, and Mn, and trace mineral source (inorganic vs. chelated) on growth performance, mineral status, and fecal mineral concentrations from weaning through development. The study was conducted over three trials with 72 pigs in each trial. Gilts were blocked by weight and randomly assigned to either 1) control, 2) reduced inorganic, or 3) reduced chelated trace minerals. The control diet was supplemented with 25, 150, 180, and 60 mg/kg of Cu, Zn, Fe, and Mn (in sulfate forms), respectively, during the nursery phase and 15, 100, 100, and 40 mg/kg of supplemental Cu, Zn, Fe, and Mn, respectively, during the growing and gilt-developer phases. Reduced inorganic and reduced chelated treatments were supplemented during all phases with 5, 25, 25, and 10 mg/kg of Cu, Zn, Fe, and Mn, respectively. The reduced chelated treatment supplied 50% of the supplemental Cu, Zn, Fe, and Mn in the form of metal proteinates, with the remainder from sulfate forms. Performance by control pigs did not differ from pigs fed the reduced trace mineral treatments during the nursery and grower-development periods. Gain:feed was lower (P < 0.05) for pigs fed the reduced inorganic compared with those fed the reduced chelated treatment during the nursery period. Trace mineral source did not affect performance during the growing or gilt-developer phase. Plasma Zn concentration and alkaline phosphatase activity were higher (P < 0.01) in control pigs than in those receiving reduced trace minerals during the nursery and growing phases. Plasma Cu concentration and ceruloplasmin activity were generally not affected by treatment. Hemoglobin concentrations were lower (P < 0.05) for the reduced inorganic compared with the reduced chelated treatment in the nursery phase. Fecal concentrations of Cu, Zn, and Mn were lower (P < 0.05) in pigs fed reduced trace minerals than in controls during all production phases. Fecal Zn concentration during the nursery and fecal Cu concentrations during the growing and gilt-developer phases were lower (P < 0.05) in pigs fed the reduced chelated compared with the reduced inorganic treatment. Results indicate that reducing the concentrations of Zn, Cu, Mn, and Fe typically supplemented to pig diets will greatly decrease fecal mineral excretion without negatively affecting pig performance from weaning through development.     

Effects of dietary organic and inorganic trace mineral levels on sow reproductive performances and daily mineral intakes over six parities

Dietary trace mineral sources and levels were fed to developing gilts to evaluate their performance responses during the growth phase, but treatments were continued into the reproductive phase in which subsequent reproductive responses were evaluated. In Exp. 1, three groups of gilts (n = 216) were used in a 2 x 2 factorial in a randomized complete block design (6 replicates) with treatment diets initially fed at 30 kg of BW. The first factor was trace mineral source (organic or inorganic), whereas the second factor evaluated dietary levels. The NRC requirement was the first level evaluated, whereas the second level was formulated to average industry standards (IND). Organic trace minerals were mineral proteinates, whereas the inorganic minerals were provided in salt form. The results of Exp. 1 indicated that trace mineral source or level did not affect gilt growth or feed performance responses to 110 kg of BW. Experiment 2 continued with the same females but was a 2 x 3 factorial in a split-plot design using 3 groups of females over a 6-parity period and had a total of 375 farrowings. Factors in Exp. 2 were the same as in Exp. 1, except that 2 additional pens of gilts during their development had been fed the IND level trace mineral levels of both trace mineral sources. At breeding, the gilts from these 2 additional pens were continued on the same trace mineral source and level but fed greater dietary Ca and P levels (IND + Ca:P). Litters were standardized by 3 d postpartum within each farrowing. Sows fed organic trace minerals farrowed more (P < 0.05) total (12.2 vs. 11.3) and live pigs (11.3 vs. 10.6) compared with sows fed inorganic trace minerals. Sows fed the IND + Ca:P level tended to have fewer (P < 0.10) total pigs born for both trace mineral sources. Litter birth weights were heavier (P < 0.05) when sows were fed organic trace minerals, but individual piglet weights were similar. Nursing pig ADG tended to be greater (P < 0.10) when sows were fed organic trace minerals. Other sow reproductive traits (BW, feed intake, and rebreeding interval) were not affected by trace mineral source or level. Daily mineral intake increased by parity but declined when trace mineral intakes were expressed on an amount per kilogram of BW and declined during later lactations. These results suggest that feeding sows organic trace minerals may improve sow reproductive performance, but there were minimal effects on other reproductive measurements.     

Effects of copper and zinc source on performance and humoral immune response of newly received, lightweight beef heifers

Two experiments were conducted to evaluate the effects of Cu and Zn source on performance, morbidity, and humoral immune response in lightweight, newly received beef heifers. A 2 x 2 factorial arrangement of treatments was used in both experiments, with either a sulfate or a polysaccharide mineral complex (SQM) source of both Cu and Zn as the factors. Supplemental Cu and Zn were included in the receiving diet at concentrations designed to provide 10 mg of Cu/kg and 75 mg of Zn/kg (DM basis). In Exp. 1, 219 newly received beef heifers (British x Continental, average initial BW = 208 kg) were given ad libitum access to a 65% concentrate diet for 35 d to determine treatment effects on DMI, ADG, G:F, and bovine respiratory disease (BRD) morbidity. In Exp. 2, 24 heifers (average initial BW = 272 kg) were fed a diet with no supplemental Cu or Zn for 35 d, followed by fasting-refeeding-fasting stress, after which the same treatment diets used in Exp. 1 were fed for 21 d to examine the effects on humoral immune response (plasma IgG titer determined by ELISA on d 7, 14, and 21) to an ovalbumin (OVA) vaccine given on d 0 and 14. Copper source x Zn source interactions were not detected in either experiment. In Exp. 1, neither Cu nor Zn source affected (P > 0.10) DMI, ADG, G:F, or BRD morbidity. In Exp. 2, d 14 (P = 0.02) and 21 (P = 0.06) OVA titers were greater for heifers that received SQM Zn compared with heifers receiving ZnSO4, but heifers receiving CuSO4 had greater OVA titers than did heifers on the SQM Cu treatment on d 14 (P = 0.01) and 21 (P = 0.001). In summary, neither supplemental Cu nor Zn source affected performance or morbidity of lightweight, newly received heifers; however, source of both Cu or Zn affected the humoral immune response to OVA, although source effects were not consistent for the two minerals.     

Effect of mannan oligosaccharides and fructan on growth performance, nutrient digestibility, blood profile, and diarrhea score in weanling pigs

A total of 150 weanling pigs [(Yorkshire × Landrace) × Duroc] with an average BW of 7.22 ± 0.80 kg (21 d of age) were used in a 28-d trial to determine the effects of dietary fructan and mannan oligosaccharides on growth performance, nutrient digestibility, blood profile, and diarrhea score in weanling pigs. Pigs were allotted randomly to 1 of 5 dietary treatments: 1) negative control (NC), basal diet; 2) positive control (PC), NC + 0.01% apramycin (165 mg/kg); 3) NC + 0.1% fructan (FC); 4) NC + 0.1% mannan oligosaccharide source (MO); and 5) NC + 0.05% fructan + 0.05% mannan oligosaccharide source (FM). There were 3 replications per treatment with 10 pigs per pen (5 barrows and 5 gilts). From d 0 to 14, ADG and ADFI of pigs fed the PC, MO, and FM diets were greater (P < 0.05) than pigs fed the NC diet. From d 15 to 28, there were no differences (P > 0.05) in ADG, ADFI, and G:F. During the overall period (d 0 to 28), pigs fed the MO diet had a greater ADG than pigs fed the NC diet (P < 0.05). Pigs fed the PC and MO diets increased ADFI (P < 0.05) compared with pigs fed the NC diet. However, no differences were detected among dietary treatments in G:F during the overall experimental period. On d 14, the apparent total tract digestibility (ATTD) of DM and N in pigs fed the PC, MO, and FM diets was greater (P < 0.05) than pigs fed the NC diet. The ATTD of DM increased (P < 0.05) in pigs fed the MO and FM diets compared with pigs fed the FC diet. However, at the end of the experiment, pigs fed the FM diet had a greater (P < 0.05) ATTD of DM compared with pigs fed the NC diet. Additionally, there were no differences in IgG, red blood cells, white blood cells, and lymphocyte counts among dietary treatments on d 0, 14, or 28. The diarrhea score in pigs fed the MO diet was reduced (P < 0.05) compared with pigs fed the NC diet. In conclusion, mannan oligosaccharides have a beneficial effect on growth performance and nutrient digestibility in weanling pigs. Furthermore, mannan oligosaccharides can decrease diarrhea score in weanling pigs.