An evaluation of a dry-fat product as a source of supplemental energy in pig diets

Three feeding trials (278 pigs) and one balance trial (14 pigs) were conducted to evaluate acceptance and utilization of diets containing a dry-fat product containing 90% fat. The fat was a mixture of equal parts vegetable and animal fats. In Trial 1, 4-wk-old pigs fed diets with 5% dry-fat added had average daily gain (ADG), average daily feed intake (ADFI) and gain/feed (G/F) values equal to pigs fed the diet containing 4.5% liquid fat, the unprocessed equivalent to the dry-fat. Values for G/F with both diets were higher (P less than .05) than for pigs fed the unsupplemented control diet. In Trial 2, dry-fat and roasted soybeans were compared as sources of supplemental fat in diets for finishing pigs. Both were efficiently utilized, with no differences (P greater than .05) among diets. In Trial 3, diets with 0, 5 and 10% levels of added dry-fat were fed to pigs from 34 to 100 kg. Rates of gain were not affected, but ADFI decreased (P less than .05) and G/F increased (P less than .05) with increased fat level. Carcass measurements were not affected by dietary treatment, but iodine number of backfat increased (P less than .05) with dietary fat level. In Trial 4, values for grams of N absorbed and retained and megacalories of energy absorbed and metabolized did not differ (P greater than .05) between diets with 0 and 5% added dry-fat. These results show that the dry-fat product was efficiently utilized by growing and finishing pigs.     

Effects of dietary pH and phosphorus source on performance, gastrointestinal tract digesta, and bone measurements of weanling pigs.

Crossbred pigs (n = 144, average age and weight = 28 +/- 3 d, 7.5 kg) were used in two 6-wk trials to assess the effects of dietary pH and P source on growth performance, gastrointestinal digesta pH and chloride ion concentration (Cl-), and bone characteristics. Treatments were randomly allotted within blocks (based on weight within gender) to a 3 x 2 factorial arrangement with three dietary pH levels (5.4, 6.0, and 6.7) and two P sources: dicalcium phosphate (DCP) and defluorinated phosphate (DFP). Pigs fed the pH 6.7 diet had reduced ADG (P less than .01) and average daily feed intakes (ADFI; P less than .001) during wk 1 to 3 and overall compared with pigs fed the pH 6.0 diet, but ADG and ADFI were not affected when the pH 5.4 diet was fed. There was a dietary pH x P source interaction (P less than .05) for ADFI. Pigs had decreased ADFI as dietary pH was increased from 6.0 to 6.7 for both DCP and DFP, but ADFI was similar for the pH 6.0 and 5.4 diets with DFP, whereas ADFI was greater for the pH 5.4 diet with DCP. Dietary pH did not influence ADFI:ADG ratio (F:G; P greater than .05), and P source had no effect (P greater than .05) on either ADG, ADFI, or F:G.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of select menhaden fish meal in starter diets for pigs

Two trials were conducted to evaluate a select menhaden fish meal (SMFM) as a protein source in starter diets for 390, 3-wk-old weaned pigs. Initial weights averaged 4.8 and 5.5 kg in Trials 1 and 2, and trials were conducted for 5 and 4 wk, respectively. Diets in Trial 1 were formulated by substituting levels of 0, 4, 8, 12, 16 or 20% SMFM for soybean meal plus corn on a protein basis. The 20% fish meal diet contained no soybean meal; all diets contained between 19.8 and 20.2% CP, between 1.34 and 1.40% lysine and 25% dried whey. Replacement of soy protein with fish meal elicited a quadratic improvement (P = .01) in cumulative ADG and average daily feed intake (ADFI) by the end of wk 5. The diet containing 8% SMFM resulted in the maximum observed ADG; however, the maximum ADFI occurred in pigs fed the diet containing 12% SMFM. Breakpoint analysis indicated that 4.5 and 9.3% SMFM maximized ADG and ADFI, respectively. Addition of SMFM did not affect efficiency of feed utilization (F/G). In Trial 2, a 2 X 3 factorial with two levels of dried whey (10 or 20%) and three levels of SMFM (0, 4 or 8%), a SMFM X dried whey interaction (P less than .05) was observed for cumulative ADG and F/G by the of wk 4 with greater benefit from SMFM with 10% than with 20% dried whey.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of conjugated linoleic acid and dietary antibiotics as growth promotants in weanling pigs.

An experiment was conducted to determine the efficacy of dietary conjugated linoleic acid (CLA) as a growth promotant in weanling swine. Weanling pigs (n = 192; 7.6 kg and 29 d of age) were randomly assigned to four treatments that were arranged as a 2 x 2 factorial. Concentrations of dietary CLA (0 or 0.6%) and antibiotics (+/-) constituted the main effect variables. Dietary CLA treatments consisted of a 1% addition of an oil containing 60% CLA isomers or 1% soybean oil, and dietary antibiotic treatments were antibiotics or no antibiotics. The experimental diets were fed for 9 wk in four phases (1, wk 1; 2, wk 2 and 3; 3, wk 4 through 6; and 4, wk 7 through 9), after which all pigs were fed identical medicated diets for the duration of the finishing phase. Live weights were recorded at wk 17 postweaning and at marketing to determine any residual effects of dietary treatments on finisher ADG and days to market. Medicated diets fed during phases 1 and 2 contained 55 mg carbadox/kg; during phase 3 contained 299 mg tilmicosin/kg; and during phase 4 contained 110 mg tylosin and 110 mg sulfamethazine/kg. Pigs fed medicated diets had higher overall ADG than pigs fed unmedicated diets for wk 0 through 9 (P < 0.03). Gain:feed (G:F) was greater for pigs fed medicated diets than for pigs fed unmedicated diets during phase 1 (P < 0.03) and for the duration of the nursery phase (P < 0.03). There were no effects of CLA on ADG, ADFI, or G:F. There were no residual effects of nursery CLA or antibiotics on finisher ADG and days to market. Blood samples collected from a subset of pigs (n = 72) at the completion of phases 2, 3, and 4 were assayed for serum IGF-I and antibody concentrations to porcine reproductive and respiratory syndrome virus (PRRSV) and Mycoplasma hyopneumoniae. There was a tendency for pigs fed medicated diets to have greater IGF-I concentrations than pigs fed unmedicated diets at the completion of phase 4 (P < 0.06). Pigs fed CLA had greater antibody titers (P < 0.02) to Mycoplasma hyopneumoniae at d 63 than pigs fed diets without CLA. These results indicate that feeding 0.6% dietary CLA did not enhance growth performance in weanling swine and that the use of dietary antibiotics can increase production efficiency in nursery pigs. Furthermore, there were no interactions between CLA and dietary antibiotics on the variables addressed in this study.     

Influence of dietary protein, fat or amino acids on the response of weanling swine to aflatoxin B1

Two experiments were conducted using corn from clean or aflatoxin B1 (AFB1)-contaminated (182 ppb) sources. Weanling pigs (28 d) were fed one of eight dietary treatments arranged in a 2 x 2 x 2 factorial design. In Exp. 1 (192 pigs), treatments varied in corn source (clean or AFB1-contaminated), CP level (18 or 20%) and added fat (0 or 5%). At the end of the 28-d growth trials, plasma samples were obtained. An AFB1 x CP level interaction was detected (P less than .05) for growth rate (ADG), feed intake (FI) and feed/gain ratio (F/G). Feeding AFB1 reduced (P less than .05) ADG (.30 vs .37 kg/d) and FI (.57 vs .66 kg/d) and increased F/G (1.88 vs 1.78) of pigs fed 18% CP diets. Performance of pigs fed 20% CP diets was not altered by AFB1. Adding 5% fat to diets improved (P less than .05) F/G but did not improve ADG of pigs fed AFB1. There was an AFB1 x CP x fat interaction (P less than .05) for plasma cholesterol. Adding fat or increasing the CP level prevented the depression of plasma cholesterol in pigs fed AFB1. In Exp. 2 (96 pigs), all diets contained 18% CP and the treatments varied in corn source (clean or AFB1-contaminated), added L-lysine HCl (0 or .25%) and added DL-methionine (0 or .15%). Feeding AFB1 reduced (P less than .05) ADG of pigs fed the 18% CP diet (.44 vs .50 kg/d) but not of pigs fed diets supplemented with .25% lysine.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of dietary energy density and lysine:calorie ratio on growth performance and carcass characteristics of growing-finishing pigs

We conducted two experiments to evaluate the effects of dietary energy density and lysine:calorie ratio on the growth performance and carcass characteristics of growing and finishing pigs. In Exp. 1, 80 crossbred barrows (initially 44.5 kg) were fed a control diet or diets containing 1.5, 3.0, 4.5, or 6.0% choice white grease (CWG). All diets contained 3.2 and 2.47 g of lysine/Mcal ME during growing (44.5 to 73 kg) and finishing (73 to 104 kg), respectively. Increasing energy density did not affect overall ADG; however, ADFI decreased and feed efficiency (Gain:feed ratio; G:F) increased (linear, P < .01). Increasing energy density decreased and then increased (quadratic, P < .06) skinned fat depth and lean percentage. In Exp. 2, 120 crossbred gilts (initially 29.2 kg) were used to determine the effects of increasing levels of CWG and lysine:calorie ratio fed during the growing phase on growth performance and subsequent finishing growth. Pigs were fed increasing energy density (3.31, 3.44, or 3.57 Mcal ME/kg) and lysine:calorie ratio (2.75, 3.10, 3.45, or 3.80 g lysine/Mcal ME). No energy density x lysine:calorie ratio interactions were observed (P > .10). Increasing energy density increased ADG and G:F and decreased ADFI of pigs from 29.5 to 72.6 kg (linear, P < .05). Increasing lysine:calorie ratio increased ADG and ADFI (linear, P < .01 and .07, respectively) but had no effect on G:F. From 72.6 to 90.7 kg, all pigs were fed the same diet containing .90% lysine and 2.72 g lysine/Mcal ME. Pigs previously fed with increasing lysine:calorie ratio had decreased (linear, P < .02) ADG and G:F. Also, pigs previously fed increasing CWG had decreased (linear, P < .03) ADG and ADFI. From 90.7 to 107 kg when all pigs were fed a diet containing .70% lysine and 2.1 g lysine/Mcal ME, growth performance was not affected by previous dietary treatment. Carcass characteristics were not affected by CWG or lysine:calorie ratio fed from 29.5 to 72.6 kg. Increasing the dietary energy density and lysine:calorie ratio improved ADG and G:F of growing pigs; however, pigs fed a low-energy diet or a low lysine:calorie ratio from 29 to 72 kg had compensatory growth from 72 to 90 kg.     

Effect of vitamin E and copper on the vitamin E status and performance of growing pigs

A 13-wk trial was conducted with 32 pigs to determine the effects of dietary Cu (250 ppm) and alpha-tocopheryl acetate (ATA, 22 IU/kg) on the performance, serum enzymes, serum and tissue tocopherols, and antibody production in growing pigs. Pigs were fed corn-soybean meal diets containing 21% CP the first 4 wk and 18% CP during the rest of the trial. All feed was stored a minimum of 14 d before it was fed. The addition of Cu decreased (P less than .01) the concentration of alpha-tocopherol in the feed. alpha-Tocopherol concentrations were less than .01 mg/kg in the starter diet and less than 2 mg/kg in the grower diet after 14 d of storage. Supplemental Cu or ATA had no effect on ADG, feed intake, or gain:feed during the first 4 wk. During wk 5 to 13, the addition of Cu to diets containing no ATA increased daily feed intake and decreased gain:feed, but with ATA addition, feed intake decreased and gain:feed increased, resulting in a Cu x ATA interaction (P less than .05). The addition of Cu or ATA had no effect (P greater than .1) on serum glutathione peroxidase or lactic dehydrogenase activity. Serum tocopherols were reduced (P less than .05) by the addition of Cu during wk 1 to 4, 6 (P less than .01), and 7 (P less than .05) and increased (P less than .01) by ATA addition during the entire experiment. The addition of ATA increased the tocopherol concentrations in bile, ham, heart, pancreas, kidney, spleen, liver, psoas and longissimus muscle (P less than .01), kidney fat, backfat, and adrenal gland (P less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of marketing treatments and transportation on feeder pig performance

During four 6-wk trials, 376 university-raised, crossbred feeder pigs were used to determine the effects of fasting (no feed or water) vs providing feed plus water or water alone at the simulated market and a 563-km transport on shrinkage and subsequent health and performance. Providing feed and water or water alone during a 12-h market simulation for Trials 1, 2 and 4 or a 24-h period for Trial 3 did not affect subsequent rate of gain (ADG) or feed efficiency (F/G) compared with pigs fasted during the market stay. However, overall shrinkage (market phase plus transportation) of pigs provided feed and water at the market was less (P less than .05) than for fasted pigs (4.0 vs 8.4% for Trials 1, 2 and 4; 4.5 vs 11.8% for Trial 3). Transporting the fasted or nonfasted feeder pig 563 k did not affect subsequent health or performance. Overall shrinkage of the fasted pigs that were transported 563 km vs those that were not transported during Trial 4 was not different (8.8 vs 9.1%; P greater than .05). In conclusion, one-owner feeder pigs can cope with the stress of fasting and transporting long distances without any extended detrimental effects on subsequent health and performance.     

The interrelationship between crude protein and exogenous porcine somatotropin on growth, feed and carcass measurements of pigs

In three experiments the interrelationship between dietary CP and recombinant porcine somatotropin (rpSt, i.m. daily) on ADG, feed efficiency (F/G) and carcass traits was examined in crossbred Yorkshire gilts and barrows given ad libitum access to their diets during the finishing period (55 to 110 kg BW). Pigs, blocked by BW and gender, were assigned (four/pen) within block. In Exp. 1, 140 pigs were assigned two/gender per pen to each of five pens/block and received a diet of either 12%, 18% or 24% CP (n = 2, 1 and 2 pens/block, respectively). Pigs received rpSt, either 0 or 120 micrograms/kg BW (12% and 24% CP groups) or 60 micrograms/kg BW (18% CP group). When CP was 12%, rpSt decreased ADG and increased F/G (P less than .05), whereas when CP was 18% or 24%, rpSt increased ADG and lowered F/G (P less than .05). Backfat thickness was reduced (P less than .05) by rpSt regardless of CP. In Exp. 2, 120 pigs were assigned two/gender per pen to each of five pens/block and received a diet of 24% CP. Either 0, 15, 30, 60 or 120 micrograms of rpSt/kg BW was administered to each pig. All doses of rpSt increased ADG, lowered F/G and decreased backfat thickness compared with measurements for control pigs (P less than .05). In Exp. 3, 140 pigs were assigned two/gender per pen to each of seven pens/block and received a diet of either 14%, 18% or 24% CP (n = 3, 2 and 2 pens/block, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

Influence of direction of body weight change on pattern of gonadotropin secretion in ovariectomized beef heifers of equivalent body weight

Our hypothesis was that alterations in pattern of gonadotropin secretion induced by level of dietary energy intake are dependent on direction of BW change. Beef heifers were assigned to one of two treatments 21 d after ovariectomy: 1) increasing followed by decreasing BW (I-D; n = 9) or 2) decreasing followed by increasing BW (D-I; n = 9). Heifers assigned to the I-D treatment received 15.4 Mcal ME/d (HE) from wk 0 to 8 followed by 4.3 Mcal ME/d (LE) from wk 9 to 16. Heifers assigned to the D-I treatment received the LE diet for the initial 8 wk followed by the HE diet for the subsequent 8 wk. At 2-wk intervals blood samples were collected at 10-min intervals for 11 h to determine the pattern of secretion and(or) concentration of gonadotropins in circulation (LH and FSH) and pituitary responsiveness to administration of 750 ng and 50 micrograms of LHRH. Frequency of LH pulses increased (P less than .05) in a quadratic fashion with increasing ADG in heifers in both treatment groups. Amplitude of LH pulses decreased (P less than .05) in a linear fashion with increasing ADG in heifers in both treatment groups and magnitude of this decline was greater (P less than .05) in heifers receiving the D-I treatment. Amplitude of response to 750 ng of LHRH decreased (P less than .05) in a linear fashion with increasing ADG in heifers receiving the D-I treatment but was unrelated to changes in ADG (P greater than .05) in heifers receiving the I-D treatment. When heifers in both treatment groups attained similar BW (P greater than .05; wk 14), amplitude of LH pulses, responsiveness to 750 ng of LHRH and mean concentration of FSH in serum were higher (P less than .05) in heifers receiving the I-D than in heifers receiving the D-I treatment. Thus, we accept the hypothesis that alterations in pattern of gonadotropin secretion in heifers fed diets with a low energy content are dependent on direction of BW change.     

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.     

Evaluation of the effect of fumaric acid and sodium bicarbonate addition on performance of starter pigs fed diets of different types.

Three growth experiments were conducted to assess the effect of fumaric acid (FA) supplementation on the performance of pigs fed different types of diets. These 4-wk experiments involved 550 crossbred pigs weaned at 30 +/- 3 d of age. Pigs in Exp. 1 were fed either a simple corn-soybean meal (SBM) diet or a 75% corn-SBM, 25% dried skim milk (DSM) diet. Zero, 2, or 3% FA were added to the diets to create a 2 x 3 factorial arrangement of treatments. Supplementing diets with DSM improved gain (P less than .05) and gain/feed (P less than .001). Fumaric acid addition improved efficiency of feed utilization (P less than .01). Experiment 2 was conducted to evaluate the effect of protein source (casein or soy protein concentrate [SPC]) on the response to 3% FA. Sodium bicarbonate (BCB; 2.75%) was added to one diet containing casein and FA to negate the effect of FA on growth performance. Addition of FA improved gain and feed efficiency (P less than .05) during the first 2 wk.(ABSTRACT TRUNCATED AT 250 WORDS)     

Feed intake and weight gain of growing goats fed diets of various energy and protein levels

Growing goats, 45 Alpine and 45 Nubian, were used in a 3 x 3 factorial arrangement to quantify the influence of dietary energy and protein levels on daily DM intake and nutrient utilization for growth. Goats had ad libitum access to complete mixed diets containing either 2.46, 2.77 or 3.05 Mcal/kg ME plus 11.2, 12.7 or 15.1% CP for 16 wk. Dry matter intake decreased curvilinearly as dietary ME density increased (P less than .001). Dry matter intake increased linearly (P less than .05) as dietary CP level increased during all growth intervals except wk 25 to 28 of age. Average daily gain was 115, 113 and 99 g/d for goats fed diets containing 2.46, 2.77 and 3.05 Mcal/kg ME, respectively. Average daily gain was 104, 106 and 117 g/d for goats fed diets with 11.2, 12.7 and 15.1% CP, respectively. Dry matter intake was higher (P less than .01) for Alpine than for Nubian goats, whereas ADG was similar between breeds. Intake of ME was 248, 260 and 198 kcal/(kg.75.d) for goats fed the low- medium- and high-energy diets, respectively. Intake of CP was 9.1, 10.7 and 13.2 g/(kg.75.d) for goats fed low-, medium- and high-protein diets, respectively. Average requirements for growth derived from regression analysis of all data points were 4.6 kcal ME and .26 g CP/g ADG. The prediction equation for intake of growing goats of 4 to 8 mo of age was: DMI, g/d = 1,749 - 496 DE, kcal/g + 18 live weight, kg + 3 ADG, g/d; r2 = .73 (Sy.x = 127, P less than .0001, n = 90). The requirement of ME for growth was 33% lower than the value recommended in 1981 by the National Research Council.     

Assessment of lactose level in the mid- to late-nursery phase on performance of weanling pigs

An experiment involving a total of 1,320 crossbred pigs was conducted at 3 universities to assess the effects of various levels of lactose in diets during phase 3 (wk 3 and 4 postweaning) of a 4-phase starter program. Pigs were weaned at 15 to 20 d (6.2-kg initial BW) and allotted to 5 treatments. All pigs were fed a complex phase 1 diet (20% lactose) the first week postweaning followed by a complex phase 2 diet (15% lactose) the second week postweaning. Phase 3 diets containing 0, 2.5, 5.0, 7.5, or 10.0% lactose were fed for wk 3 and 4, and then a common, corn-soybean meal diet was fed for an additional 1 to 2 wk (phase 4). The source of lactose was Dairylac 80, which contains 80% lactose. The phase 1, 2, and 3 diets were prepared at one site. Pigs were weighed, and feed intake was determined at weekly intervals. There were 8 replications at each station for a total of 24 replications per treatment with 5 or 23 pigs per pen. As expected, ADG, DFI, and G:F were not affected (P = 0.10) during the initial 2-wk period when all pigs received the same diet. During wk 3 and 4 (phase 3) when the 5 levels of lactose were fed, ADG and ADFI increased linearly (P < 0.01) with increasing levels of lactose, but G:F was not affected (P = 0.10). Although the quadratic component was not significant, ADG and ADFI reached a numerical plateau at the 7.5% inclusion level of lactose during phase 3. Compared with pigs fed the diet without lactose, the 7.5% level of lactose resulted in 350 g of additional BW gain coupled with 420 g of additional feed consumed per pig during phase 3, and most of the additional BW gain (294 g) was maintained through the end of the 5- to 6-wk study. These results suggest that pigs respond to dietary lactose during the mid to latter phase of the nursery period and that the response was obtained under different management and facility conditions.     

Zinc-amino acid complexes for swine

Two experiments were conducted to determine the effect of sources of dietary zinc on gain, feed conversion and blood and bone traits of swine. In the first experiment 96 pigs were used in a 28-d study. The pigs were fed diets with no supplemental Zn or with either 9 or 12 ppm supplemental Zn from zinc sulfate (ZnSO4), zinc methionine (ZnMet) or zinc methionine with picolinic acid (ZnMet w/PA), each with or without 5% added corn oil. There were differences (P less than .05) in average daily gain (ADG) and average daily feed intake (ADFI) between the pigs fed the two organic Zn sources, with those fed ZnMet w/PA showing the better gains and feed conversion. However, neither organic Zn source resulted in pig performance that was different from either the diet with no supplemental Zn or the diets supplemented with Zn from ZnSO4. In the second experiment the same dietary Zn sources and treatments were fed as in Exp. 1 except that corn oil was deleted as a variable. No differences in ADG, ADFI, feed/gain (F/G) or in changes in serum Zn or Cu were observed among treatments during either the 21-d nursery or the 56-d growing periods. During the subsequent 56-d finishing period ADG and ADFI were greater (P less than .01) for pigs fed the Zn-supplemented diets than for those fed the diets without supplemental Zn. There were no differences among treatments in F/G during the finishing period. Zn content of bone ash was lower (P less than .01) in the non-Zn-supplemented pigs. These data suggest that the Zn sources used are of similar biological value and do not support the theory that picolinic acid aids Zn absorption.     

Escherichia coli phytase improves growth performance of starter, grower, and finisher pigs fed phosphorus-deficient diets

Corn-soybean meal-based diets, consisting of a high-P control (HPC) containing supplemental dicalcium phosphate (DCP), a basal diet containing no DCP, and the basal diet plus Escherichia coli phytase at 500 or 1,000 phytase units per kilogram (FTU/kg; as-fed basis) were fed to evaluate growth performance in starter, grower, and finisher pigs. Pigs were blocked by weight and gender, such that average weight across treatments was similar, with equal numbers of barrows and gilts receiving each treatment in each block. In Exp. 1, 48 pigs with an average initial BW of 11 kg, housed individually, with 12 pens per diet, were used to evaluate growth performance over 3 wk. Overall ADG and G:F were increased linearly (P < 0.05) by dietary phytase addition. Final BW and plasma P concentrations at 3 wk also increased linearly (P < 0.05). In Exp. 2, 128 pigs with an average initial BW of 23 kg, housed four pigs per pen, with eight pens per diet, were used to evaluate growth performance over 6 wk. A linear increase in response to phytase was noted for ADG and G:F in all three 2-wk periods, as well as overall (P < 0.05). Percentage of bone ash also showed a linear increase (P < 0.01). In Exp. 3, 160 pigs (53 kg), housed five pigs per pen, with eight pens per diet, were used to evaluate growth performance over 6 wk. A linear increase was detected for final BW, as well as ADG and G:F in the first and second 2-wk periods, and overall (P < 0.01). Twenty-four 15-kg individually housed pigs were used to evaluate total-tract nutrient digestibility in Exp. 4. Daily absorption of P linearly increased (P < 0.05) with phytase supplementation. Results of this research indicate that E. coli phytase is effective in liberating phytate P for uptake and utilization by starter, grower, and finisher pigs.     

Effects of zeolite a or clinoptilolite in diets of growing swine

Growth, nutrient balance, plasma ammonia levels and urinary p-cresol excretion were evaluated in growing pigs fed diets containing various levels of zeolite A or clinoptilolite. In one growth trial, crossbred pigs averaging 25 kg initial body weight were assigned to diets containing no zeolite, .3% zeolite A or .5% clinoptilolite for a 6-wk growing phase trial. Average daily gain (ADG), average daily feed intake (ADF) and feed/gain (F/G) were unaffected by supplementation of either zeolite in the diet, but metabolizable energy (ME) utilization was improved by feeding diets containing either zeolite. A second growth trial utilized the same crossbred pigs, which averaged 65 kg initial body weight, and were assigned to diets containing no zeolite, 1% zeolite A or 5% clinoptilolite for an 8-wk finishing phase trial. Average daily gain, ADF, and ME utilization were unaffected by feeding either zeolite diet, while F/G was increased in pigs fed the diet containing 5% clinoptilolite. In two nutrient balance trials, 16 crossbred pigs averaging 7.5 kg in initial body weight were fed diets containing 0, 1, 2 or 3% zeolite A in one trial and 16 crossbred pigs averaging 7.0 kg initial body weight were fed diets containing 0, 2.5, 5.0 or 7.5% clinoptilolite in a second trial. In both trials, digestible energy, ME, N-corrected ME and ME corrected for N balance and zeolite levels were linearly reduced as increasing amounts of either zeolite were fed. Daily fecal N increased and apparent digestibility of N was linearly reduced by feeding increasing amounts of zeolite A or clinoptilolite. Biological value of protein was improved linearly as higher levels of zeolite A were fed, indicating that there may be some ammonia binding to zeolite A in the gastrointestinal tract. Net protein utilization was reduced by feeding increasing levels of clinoptilolite in the diet. Calcium, P, Mg, Na, K and Fe retentions were linearly reduced by feeding increasing amounts of zeolite A in the diet, while increasing levels of clinoptilolite caused only P retention to be linearly reduced. Both free and conjugated forms of urinary p-cresol were linearly reduced by feeding increasing levels of clinoptilolite. Plasma ammonia levels were reduced at subsequent bleedings after a meal and by increasing levels of clinoptilolite.     

Effect of vitamin E and fat source in sows' diets on immune response of suckling and weaned piglets

Thirty-six 7-mo-old gilts were used to study the effects of dietary vitamin E and fat source (5% sunflower oil or animal fat) in pregnant and lactating sow diets on serum vitamin E concentration and on cell-mediated and humoral immune response in suckling and weaned piglets. Six gilts each received one of six diets throughout pregnancy and lactation. The basal diets (13 mg alpha-tocopherol/kg diet) were supplemented with dl-alpha-tocopheryl acetate to 48 and 136 mg alpha-tocopherol/kg of feed (average analyzed values). After weaning (at 4 wk of age) all pigs received identical diets (20 mg of alpha-tocopherol/kg feed). One week after weaning, pigs were immunized (i.m. with ovalbumin and tetanus toxoid) and antibody production was measured. Blood samples were taken immediately after birth, at 1 wk after birth, at weaning, and at four weekly intervals after weaning. Samples were analyzed for alpha-tocopherol concentration, total number of leukocytes, T- and B-lymphocytes, lymphocyte stimulation with concanavalin A, lysozyme activity, and immunoglobulin concentrations. It was concluded that a high vitamin E level in the sow's diet increased serum vitamin E concentration of 1-wk-old pigs (P less than .05). Immune response against ovalbumin was increased (P less than .05) at 1 wk of age after immunization for weaned pigs from sows fed the high level of vitamin E. Also, the phagocytic measures of pigs at 1 wk of age were increased by the medium vitamin E level (P less than .05). Fat sources in the sow's diet had no consistent effect on the immunological measures of pigs.     

Comparison of yellow dent and NutriDense corn hybrids in swine diets

Two experiments were conducted to verify the feeding value of NutriDense (ND) and Nutri-Dense Low-Phytate (NDLP) corn (Exseed Genetics LLC, BASF Plant Science, Research Triangle Park, NC) relative to that of yellow dent (YD) corn in swine diets. NutriDense corn is a high-protein, high-oil variety, and NDLP is a high-protein, high-oil, low-phytate variety. In Exp. 1, 315 nursery pigs that initially weighed 15.2 kg were used in a 21-d growth assay. Dietary treatments were arranged in a 3 x 3 factorial; main effects were corn source (YD, ND, and NDLP) and added fat (0, 3, or 6%, as-fed basis). Diets were formulated to contain 3.83 g of lysine/Mcal using calculated nutrient values. There were no corn source x fat interactions observed. Pigs fed YD, ND, and NDLP had ADG of 750, 734, and 738 g/d and G:F of 0.64, 0.66, and 0.65, respectively. No differences (P > 0.10) in ADG were observed among the three corn sources; however, pigs fed diets containing either ND or NDLP corn had decreased ADFI (P < 0.02) and improved G:F (P < 0.05) compared with pigs fed diets containing YD corn. Increasing dietary fat increased ADG (727, 746, and 748 g/d; linear, P < 0.04) and G:F (0.62, 0.66, and 0.68; linear, P < 0.01) and decreased ADFI (linear, P < 0.01). Using the NRC (1998) value for ME in YD corn, we calculated the energy value for ND and NDLP based on G:F differences compared with pigs fed YD corn. These data indicated the ME values for ND and NDLP corn are 4.5 and 2.5% greater (3,575 and 3,505 Kcal/kg), respectively, than for YD corn (3,420 Kcal/kg). In Exp. 2, 1,144 gilts (initial BW = 50.1 kg) were used in a commercial research facility to evaluate the effects of corn source (ND and YD) and added fat (0, 3, or 6%, as-fed basis) in a 2 x 3 factorial on pig performance and carcass traits. There was a corn source x fat interaction for ADFI and G:F. Increasing added fat resulted in greater changes in ADFI and G:F in pigs fed YD corn diets compared with those fed ND corn. Feeding ND corn increased ADG (main effect, P < 0.04), and greater percentages of added fat increased ADG (main effect; linear, P < 0.01). Results of Exp. 2 suggest that ND corn has 5.3% more ME than YD corn. The additional energy provided by ND corn improves G:F in both nursery and grow-finish pigs, and ND corn offers a means of formulating diets more concentrated in energy than YD corn.     

Net energy of ensiled wet corn gluten feed in corn silage diets for finishing steers.

Two trials were conducted to determine the NE value of ensiled wet corn gluten feed (WCGF) in corn silage finishing diets for beef cattle. In Trial 1, 96 Angus-crossbred yearling steers were fed corn silage-based diets containing 0, 20, 40, or 60% ensiled WCGF. Increased dietary WCGF resulted in improved DMI (linear, P less than .05), ADG (linear; P less than .05), and feed/gain (linear, P less than .05). Levels of WCGF had no (P greater than .05) effect on fat thickness, marbling, quality grade, carcass protein, and carcass fat. In Trial 2, four Angus-crossbred yearling steers were used in a 4 x 4 Latin square design to determine the effect of feeding 0, 20, 40, or 60% WCGF on DE and ME values. Level of WCGF had no (P greater than .05) effect on dietary DE and ME values. Regression equations were developed for predicting NEm (Y = 1.51 + .0009X; R2 = .22) and NEg (Y = 1.04 + .0028X; R2 = .35) in which Y = predicted diet NE values in megacalories/kilogram and X = percentage of dietary WCGF. The NEg value increased .06 Mcal/kg for each 20% increase in WCGF. Predicted NEm and NEg values for WCGF are 1.60 and 1.32 Mcal/kg, respectively.