Effect of chromium propionate and metabolizable energy on growth,carcass traits,and pork quality of growing-finishing pigs

An experiment was conducted to evaluate the dietary effects of Cr propionate (CrProp) and metabolizable energy (ME) on growth, carcass traits, and pork quality of growing-finishing pigs. One hundred forty-four Cambrough-22 barrows were allotted to four dietary treatments in a randomized complete block design (six replicates of six pigs per replicate; average initial and final body weight were 27 and 113 kg, respectively). The dietary treatments were: 1) corn-soybean meal basal (B; low ME), 2) B + 200 ppb of Cr (as CrProp), 3) B + 200 kcal ME/kg (4.5% added fat; high ME), or 4) B + 200 kcal ME/kg + 200 ppb of Cr. At trial termination, three pigs per replicate were killed to determine dietary effects on carcass traits and pork quality. Overall average daily gain, average daily feed intake, and gain:feed ratio were not affected (P > 0.10) by diet. During the early growing period, average daily gain was increased in pigs fed the CrProp-low-ME diets, but decreased in pigs fed the CrProp-high ME diets (Cr x ME, P < 0.04). Feed intake was increased (P < 0.05) in pigs fed the high-ME diets during the early growing period. Forty-five min and 24 h pH were not affected (P > 0.10) by diet. The CIE L* tended (P = 0.07) to be increased and shear force tended (P = 0.06) to be decreased in pigs fed high-ME diets. Subjective marbling was increased (P < 0.03) and longissimus muscle percentage moisture and thaw loss were decreased (P < 0.04) in pigs fed CrProp. Chromium propionate had no consistent effect on growth and carcass traits in this experiment; however, CrProp did affect some aspects of pork quality.     

Effects of dietary soy isoflavones on growth, carcass traits, and meat quality in growing-finishing pigs

Two experiments were conducted to determine the effect of soy isoflavones on growth, meat quality, and carcass traits of growing-finishing pigs. In Exp. 1, 36 barrows (initial and final BW, 26 and 113 kg, respectively) were used and each treatment was replicated four times with three pigs each. The dietary treatments were 1) corn-soybean meal (C-SBM), 2) corn-soy protein concentrate (low isoflavones, C-SPC), or 3) C-SPC + isoflavones (isoflavone levels equal to those in C-SBM). Daily gain and ADFI were increased (P < 0.10) in pigs fed the C-SPC relative to pigs fed the C-SPC + isoflavone diet in the late finishing period; otherwise, growth performance was not affected (P > 0.10) by diet. Longissimus muscle area, 10th-rib fat depth, percentage muscling (National Pork Producers Council), 24-h pH and temperature, color, firmness-wetness, marbling, drip loss, and CIE L*, a*, and b* color values were not affected (P > 0.10) by diet. Dressing percentage, carcass length, weight and percentage of fat-free lean in ham and carcass, lean gain per day, lean:fat, and ham weight were increased (P < 0.10), and ham fat and percentage fat in ham and carcass were decreased (P < 0.10) in pigs fed the C-SPC + isoflavone diet compared with pigs fed the C-SPC diet. Pigs fed the C-SPC + isoflavone diet had similar (P > 0.10) carcass traits as pigs fed the C-SBM diet, except carcass length, percentage ham lean and thaw loss were greater (P < 0.10), and total ham fat was less (P < 0.10) in pigs fed the C-SPC + isoflavone diet. In Exp. 2, 60 gilts (initial and final BW, 31 and 116 kg, respectively) were used, and each treatment was replicated five times with four pigs per replicate. The treatments were 1) C-SBM, 2) C-SBM + isoflavone levels two times those in C-SBM, and 3) C-SBM + isoflavone levels five times those in C-SBM. Daily feed intake was linearly decreased (P < 0.10) in the growing phase and increased (P < 0.10) in the late finishing phases as isoflavone levels increased; otherwise, growth performance was not affected (P > 0.10) by diet. Diet did not affect (P > 0.10) carcass traits; however, CIE a* and b* color scores and drip loss were decreased (P < 0.06) as isoflavone levels increased. Soy isoflavones decreased fat and increased lean in barrows when fed within the dietary concentrations found in typical C-SBM diets but not when fed to gilts at concentrations above those present in C-SBM diets.     

Effects of microbial phytase, low calcium and phosphorus, and removing the dietary trace mineral premix on carcass traits, pork quality, plasma metabolites, and tissue mineral content in growing-finishing pigs

An experiment was conducted to determine the effects of phytase addition, reduced Ca and available P (aP), and removing the trace mineral premix (TMP) on growth performance, plasma metabolites, carcass traits, pork quality, and tissue mineral content in growing-finishing swine. One hundred twenty cross-bred pigs (initial and final BW of 22 and 109 kg, respectively) were allotted to five dietary treatments on the basis of weight within gender in a randomized complete block design. There were three replications of barrows and three replications of gilts, with four pigs per replicate pen. The dietary treatments were as follows: 1) corn-soybean meal (C-SBM), 2) C-SBM with reduced Ca and aP, 3) C-SBM with reduced Ca and aP plus 500 phytase units/kg of diet, 4) Diet 1 without the TMP, and 5) Diet 3 without the TMP. The Ca and aP were reduced by 0.10% in the low Ca and aP diets and the diets with added phytase. Daily gain, hot carcass weight, dressing percent, kilograms of carcass lean, bone ash percent, and bone strength were decreased (P = 0.10), but liver and kidney weight were increased (P = 0.10) in pigs fed diets with reduced Ca and aP; adding phytase reversed these responses (P = 0.10). The Commission Internationale de I'Eclairage L* was decreased (P = 0.09) in pigs fed the low Ca and aP diet plus phytase relative to those fed the control diet. Removing the TMP had no effect on overall growth performance, but it increased (P = 0.03) 10th-rib backfat thickness and fasting glucose and decreased (P = 0.03) carcass length and ham weight. Liver weight and liver weight as a percentage of final BW were not affected when phytase was added to the control diet, but removing the TMP increased liver weight and liver weight as a percentage of final BW; adding phytase reversed these responses (phytase x TMP, P = 0.06). Removing the TMP decreased (P = 0.08) Zn concentrations in the bone, muscle, and liver, and Cu and Fe concentrations in the bile but increased (P = 0.08) Mn concentrations in the bile and liver of pigs. The addition of phytase reversed the negative effects of the reduced Ca and aP diets. These data indicate that removing the TMP in diets for growing-finishing pigs has no negative effects on growth performance or pork quality, but it had negative effects on carcass traits and had variable effects on tissue mineral content.     

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。     

Effect of chromium picolinate and chromium propionate on glucose and insulin kinetics of growing barrows and on growth and carcass traits of growing-finishing barrows

Two experiments were conducted to determine the effects of dietary Cr tripicolinate (CrPic) or Cr propionate (CrProp) on growth, carcass traits, plasma metabolites, glucose tolerance, and insulin sensitivity in pigs. In Exp. 1, 36 barrows (12 per treatment; initial and final BW were 20 and 38 kg) were allotted to the following treatments: 1) corn-soybean meal basal diet (control), 2) as 1 + 200 ppb Cr as CrPic, or 3) as 1 + 200 ppb Cr as CrProp. Growth performance data were collected for 28 d, and then 23 pigs (seven, eight, and eight pigs for treatments 1, 2, and 3, respectively) were fitted with jugular catheters and a glucose tolerance test (500 mg glucose/kg BW) and an insulin challenge test (0.1 IU of porcine insulin/kg BW) were conducted. Both CrPic and CrProp decreased (P < 0.05) ADG and ADFI but did not affect gain:feed (P > 0.10). Fasting plasma glucose, total cholesterol, urea N, insulin, and high-density lipoprotein cholesterol:total cholesterol concentrations were not affected (P > 0.10) by either Cr source. Pigs fed CrPic had lower (P < 0.02) fasting plasma NEFA concentrations than control pigs, but plasma NEFA concentrations of pigs fed CrProp were not affected (P > 0.10). During the glucose tolerance test, glucose and insulin kinetics were not affected by treatment (P > 0.10). During the insulin challenge test, glucose clearance was increased (P < 0.01) in pigs fed CrProp but not affected (P > 0.10) in pigs fed CrPic. Glucose half-life was decreased (P < 0.03) in pigs fed CrPic or CrProp, but insulin kinetics were not affected (P > 0.10). In Exp. 2, 48 barrows (four replicates of four pigs per replicate; initial and final BW were 23 and 115 kg) were allotted to the same dietary treatments in a growing-finishing study. Average daily gain, ADFI, and gain:feed were not affected (P > 0.10) by treatments. Carcass length tended (P = 0.10) to be greater in pigs fed CrPic than in pigs fed CrProp, but other carcass measurements were not affected (P > 0.10). Glucose kinetics from the insulin challenge test indicate that both CrPic and CrProp increase insulin sensitivity and that both Cr sources are bioavailable.     

Effect of nonwaxy and waxy sorghum on growth, carcass traits, and glucose and insulin kinetics of growing-finishing barrows and gilts

Two experiments were conducted to determine the effect of nonwaxy (amylose and amylopectin starch) or waxy (amylopectin starch) sorghum on growth, carcass traits, and glucose and insulin kinetics of pigs. In Exp. 1 (95-d), 60 crossbred barrows or gilts (initial and final BW of 24 and 104 kg) were allotted to three treatments with five replications of four pigs per replicate pen in a randomized complete block design. The dietary treatments for Exp. 1 were 1) corn-soybean meal (C-SBM) diet, 2) sorghum-SBM (red pericarp, non-waxy), and 3) sorghum-SBM (red pericarp, waxy). In Exp. 2, 28 crossbred barrows (initial and final BW of 24 and 64 kg) were allotted to two treatments with three replications of four or five pigs per replicate pen in a randomized complete block design. Growth data were collected for 49 d, and then 20 barrows were fitted with jugular catheters, and then a glucose tolerance test (500 mg glucose/kg BW), an insulin challenge test (0.1 IU of porcine insulin/kg BW), and a feeding challenge were conducted. The dietary treatments for Exp. 2 were 1) sorghum-SBM (white pericarp, nonwaxy) and 2) sorghum-SBM (white pericarp, waxy). In Exp. 1, ADG (P = 0.10) and ADFI (as-fed basis; P = 0.02) were increased (P = 0.10) and gain:feed was decreased (P = 0.04) in pigs fed the sorghum-SBM diets relative to those fed the C-SBM diet. These responses may have resulted from the lower energy content of sorghum relative to corn. Plasma NEFA concentration (collected after a 16-h fast on d 77) was decreased (P = 0.08) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. Kilograms of carcass fat was decreased (P = 0.07) in pigs fed the waxy sorghum-SBM diet relative to those fed the nonwaxy sorghum-SBM diet. In Exp. 2, there was no effect (P = 0.57 to 0.93) of sorghum starch type on growth performance by pigs. During the glucose tolerance and insulin challenge tests, there were no effects (P = 0.16 to 0.98) of diet on glucose or insulin kinetics. During the feeding challenge, glucose (P = 0.02) and plasma urea N (P = 0.06) area under the response curves from 0 to 90 min were decreased in pigs fed the waxy sorghum-SBM diet. Feeding waxy sorghum had minimal effects on growth and carcass traits relative to pigs fed corn or nonwaxy sorghum. Waxy sorghum vs. nonwaxy sorghum had no effect on glucose or insulin kinetics in pigs.     

The tryptophan requirement of growing and finishing barrows

Five experiments were conducted to determine the true ileal digestible Trp (tidTrp) requirement of growing and finishing pigs fed diets (as-fed basis) containing 0.87% (Exp. 3), 0.70% (Exp. 4), 0.61% (Exp. 5), and 0.52% (Exp. 1 and 2) tidLys during the early-grower, late-grower, early-finisher, and late-finisher periods, respectively. Treatments were replicated with three or four replications, with three or four pigs per replicate pen. Treatment differences were considered significant at P = 0.10. Experiment 1 was conducted with 27 pigs (initial and final BW of 78.3 +/- 0.5 and 109.8 +/- 1.9 kg) to validate whether a corn-feather meal (FM) tidTrp-deficient (0.07%) diet, when supplemented with 0.07% crystalline l-Trp, would result in growth performance and carcass traits similar to a conventional corn-soybean meal (C-SBM) diet. Pigs fed the corn-FM diet without Trp supplementation had decreased growth performance and carcass traits, and increased plasma urea N (PUN) concentration. Supplementing the corn-FM diet with Trp resulted in greater ADG and G:F than pigs fed the positive control C-SBM diet. Pigs fed the corn-FM diet had similar carcass traits as pigs fed the C-SBM diet, but loin muscle area was decreased and fat thickness was increased. In Exp. 2, 60 pigs (initial and final BW of 74.6 +/- 0.50 and 104.5 +/- 1.64 kg) were used to estimate the tidTrp requirement of finishing pigs. The levels of tidTrp used in Exp. 2 were 0.06, 0.08, 0.10, 0.12, or 0.14% (as-fed basis). Response variables were growth performance, PUN concentrations, and carcass traits and quality. For Exp. 2, the average of the estimates calculated by broken-line regression was 0.104% tidTrp. In Exp. 3, 4, and 5, barrows (n = 60, 60, or 80, respectively) were allotted to five dietary treatments supplemented with crystalline l-Trp at increments of 0.02%. The basal diets contained 0.13, 0.09, and 0.07% tidTrp (as-fed basis) in Exp. 3, 4, and 5, and initial BW of the pigs in these experiments were 30.9 +/- 0.7, 51.3 +/- 1.1, and 69.4 +/- 3.0 kg, respectively. The response variable was PUN, and the basal diet used in Exp. 3 and 4 contained corn, SBM, and Canadian field peas. The tidTrp requirements were estimated to be 0.167% for pigs weighing 30.9 kg, 0.134% for pigs weighing 51.3 kg, and 0.096% for pigs weighing 69.4 kg. Based on our data and a summary of the cited literature, we suggest the following total Trp and tidTrp requirement estimates (as-fed basis): 30-kg pigs, 0.21 and 0.18%; 50-kg pigs, 0.17 and 0.14%; 70-kg pigs, 0.13 and 0.11%; and in 90-kg pigs, 0.13 and 0.11%.     

Influence of dietary protein level, amino acid supplementation, and dietary energy levels on growing-finishing pig performance and carcass composition

Two experiments were conducted to determine the effects of feeding reduced-CP, AA-supplemented diets at two ambient temperatures (Exp. 1) or three levels of dietary NE (Exp. 2) on pig performance and carcass composition. In Exp. 1, 240 mixed-sex pigs were used to test whether projected differences in heat increment associated with diet composition affect pig performance. There were 10 replications of each treatment with four pigs per pen. For the 28-d trial, average initial and final BW were 28.7 kg and 47.5 kg, respectively. Pigs were maintained in a thermoneutral (23 degrees C) or heat-stressed (33 degrees C) environment and fed a 16% CP diet, a 12% CP diet, or a 12% CP diet supplemented with crystalline Lys, Trp, and Thr (on an as-fed basis). Pigs gained at similar rates when fed the 16% CP diet or the 12% CP diet supplemented with Lys, Trp, and Thr (P > 0.10). Pigs fed the 12% CP, AA-supplemented diet had a gain:feed similar to pigs fed the 16% CP diet when housed in the 23 degrees C environment but had a lower gain:feed in the 33 degrees C environment (diet x temperature, P < 0.01). In Exp. 2, 702 gilts were allotted to six treatments with nine replicates per treatment. Average initial and final BW were 25.3 and 109.7 kg, respectively. Gilts were fed two levels of CP (high CP with minimal crystalline AA supplementation or low CP with supplementation of Lys, Trp, Thr, and Met) and three levels of NE (high, medium, or low) in a 2 x 3 factorial arrangement. A four-phase feeding program was used, with diets containing apparent digestible Lys levels of 0.96, 0.75, 0.60, and 0.48% switched at a pig BW of 41.0, 58.8, and 82.3 kg, respectively. Pigs fed the low-CP, AA-supplemented diets had rates of growth and feed intake similar to pigs fed the high-CP diets. Dietary NE interacted with CP level for gain:feed (P < 0.06). A decrease in dietary NE from the highest NE level decreased gain:feed in pigs fed the high-CP diet; however, gain:feed declined in pigs fed the low-CP, AA-supplemented diet only when dietary NE was decreased to the lowest level. There was a slight reduction in longissimus area in pigs fed the low-CP diets (P < 0.08), but other estimates of carcass muscle did not differ (P > 0.10). These data suggest that pigs fed low-CP, AA-supplemented diets have performance and carcass characteristics similar to pigs fed higher levels of CP and that alterations in dietary NE do not have a discernible effect on pig performance or carcass composition.     

Effect of microbial phytase on energy availability,and lipid and protein deposition in growing swine

Two experiments were conducted to determine the effect of phytase on energy availability in pigs. In Exp. 1, barrows (initial and final BW of 26 and 52 kg) were allotted to four treatments in a 2 x 2 factorial arrangement. Corn-soybean meal (C-SBM) diets were fed at two energy levels (2.9 and 3.2 x maintenance [M]) with and without the addition of 500 phytase units/kg of diet. The diets contained 115% of the requirement for Ca, available P (aP), and total lysine, and Ca and aP were decreased by 0.10% in diets with added phytase. Pigs were penned individually and fed daily at 0600 and 1700, and water was available constantly. Eight pigs were killed and ground to determine initial body composition. At the end of Exp. 1, all 48 pigs were killed for determination of carcass traits and protein and fat content by total-body electrical conductivity (TOBEC) analysis. Six pigs per treatment were ground for chemical composition. In Exp. 2, 64 barrows and gilts (initial and final BW of 23 and 47 kg) were allotted to two treatments (C-SBM with 10% defatted rice bran or that diet with reduced Ca and aP and 500 phytase units/kg of diet), with five replicate pens of barrows and three replicate pens of gilts (four pigs per pen). In Exp. 1, ADG was increased (P < 0.01) in pigs fed at 3.2 x M. Based on chemical analyses, fat deposition, kilograms of fat, retained energy (RE) in the carcass and in the carcass + viscera, fat deposition in the organs, and kilograms of protein in the carcass were increased (P < 0.10) in pigs fed the diets at 3.2 vs. 2.9 x M. Based on TOBEC analysis, fat deposition, percentage of fat increase, and RE were increased (P < 0.09) in pigs fed at 3.2 x M. Plasma urea N concentrations were increased in pigs fed at 3.2 x M with no added phytase but were not affected when phytase was added to the diet (phytase x energy, P < 0.06). Fasting plasma glucose measured on d 28, ultrasound longissimus muscle area (LMA), and 10th-rib fat depth were increased (P < 0.08) in pigs fed phytase, but many other response variables were numerically affected by phytase addition. In Exp. 2, phytase had no effect (P > 0.10) on ADG, ADFI, gain:feed, LMA, or 10th-rib fat depth. These results suggest that phytase had small, mostly nonsignificant effects on energy availability in diets for growing pigs; however, given that phytase increased most of the response variables measured, further research on its possible effects on energy availability seems warranted.     

Effect of feather meal on live animal performance and carcass quality and composition of growing-finishing swine

A total of 252 crossbred pigs were used in two experiments to determine the effect of feeding hydrolyzed feather meal (FM) during the growing-finishing period on animal performance, carcass composition, and pork quality. All pigs were blocked by weight, and dietary treatments were assigned randomly to pens within blocks. In Exp. 1, 24 pens were randomly assigned to one of three dietary treatments: 1) control corn-soybean meal starter, grower, and finisher diets devoid of FM; 2) control diets formulated with 3% FM; and 3) control diets formulated with 6% FM. During the starter phase, there was a quadratic decrease in average daily gain (P < 0.06) and gain:feed (P < 0.01) with increasing FM, and during the grower-II phase, gain:feed increased linearly (P < 0.07) with increasing FM inclusion level. However, dietary FM had no effects (P > 0.10) on performance during the grower-I phase, finisher phase, or in the overall trial. Moreover, carcasses from pigs fed 3% FM had greater (P < 0.05) average backfat depth than carcasses of pigs fed 0 and 6% FM, but FM did not affect (P > 0.10) ham or carcass lean composition. In Exp. 2, 24 pens were randomly allotted to one of four dietary treatments: 1) positive control corn-soybean meal-based starter, grower, and finisher diets; 2) negative control corn-soybean meal- and wheat middlings-based starter, grower, and finisher diets; 3) negative control diets formulated with 3% FM; and 4) negative control diets formulated with 6% FM. Dietary FM had no effect (P > 0.10) on average daily gain, average daily feed intake, or gain:feed during any phase of the experiment. Ham weight decreased linearly (P < 0.04), whereas ham lean weight increased linearly (P < 0.09), with increasing levels of FM in the diet. Pork from pigs fed 3% FM tended (quadratic effect, P < 0.10) to receive higher Japanese color scores than pork from pigs fed either negative control or 6% FM diets. Moreover, pork color became lighter (P c 0.08), less red (P < 0.001), and less yellow (P < 0.003) as FM level was increased in swine diets. Results from these two experiments indicate that as much as 6% FM can be incorporated into isolysinic diets of growing-finishing pigs without adversely impacting animal performance, carcass composition, or pork quality.     

Effects of chromium propionate on growth, carcass traits, and pork quality of growing-finishing pigs

An experiment was conducted to determine the effect of dietary Cr propionate (CrProp) on growth, carcass traits, and pork quality of crossbred finishing gilts. Dietary treatments were 0 or 200 ppb Cr (as CrProp; as-fed basis), and each treatment was replicated four times with five gilts per replicate pen. Gilts were fed diets containing 0.82% lysine from 73 to 80 kg BW and 0.64% lysine from 80 to 115 kg BW. At the end of the trial, carcass and pork quality data were collected from four gilts per replicate. Average daily gain, ADFI, and G:F were not affected (P = 0.76 to 0.96) by CrProp. Before delivery at the abattoir, shrink loss was determined after an 18-h fast (fasting shrink) and after hauling (shipping shrink) pigs for 2.66 h (209.2 km). Fasting, shipping, and overall shrink were not affected (P = 0.14 to 0.39) by CrProp. Carcass length was increased (P = 0.03) in pigs fed CrProp. Loin muscle area, 10th-rib backfat thickness, average backfat thickness, dressing percent, muscle score, fat-free lean, and percent lean were not affected (P = 0.18 to 0.95) by CrProp. Twenty-four-hour loin pH was increased (P = 0.10) in pigs fed CrProp, but 45-min loin and ham pH and 24-h ham pH were not affected (P = 0.39 to 0.83) by CrProp. Subjective (color, marbling, firmness, and wetness) and objective (Commission Internationale de l'Eclairage L*, a*, b*) assessments of the loin muscle (at the 10th-rib interface) were not affected (P = 0.62 to 0.99) by CrProp. Forty-eight-hour drip (P = 0.10) and 21-d purge loss (P = 0.01) were decreased in pigs fed CrProp, but cook and total loss (drip + cook loss) and shear force were not affected (P = 0.35 to 0.53) by CrProp. Plasma cortisol, glucose, and lactate concentrations were not affected (P = 0.28 to 0.97) by CrProp after transportation or during exsanguination. These data indicate that CrProp may improve some aspects of pork quality (loin pH, drip and purge loss) but not growth performance or carcass traits.     

Effect of supplemental manganese on performance and carcass characteristics of growing-finishing swine

Three hundred sixteen crossbred pigs were used in two experiments to determine the effect of supplemental manganese source and dietary inclusion level during the growing-finishing period on performance and pork carcass characteristics. All pigs were blocked by weight, and treatments were assigned randomly to pens within blocks. In Exp. 1, a total of 20 pens (five pigs/pen) was randomly assigned to one of five dietary treatments consisting of control grower and finisher diets, or control diets supplemented with either 350 or 700 ppm (as-fed basis) Mn either from MnSO4 or a Mn AA complex (MnAA). In Exp. 2, a total of 36 pens (six pigs per pen) was assigned randomly to one of six dietary treatments formulated with 0, 20, 40, 80, 160, or 320 ppm (as-fed basis) Mn from MnAA. Pigs were slaughtered when the lightest block averaged 120.0 kg (Exp. 1) or at a mean BW of 106.8 kg (Exp. 2). Neither ADG nor ADFI was affected (P > 0.21) by Mn source or high inclusion level (Exp. 1); however, across the entire feeding trial, pigs consuming 320 ppm Mn from MnAA were more (P < 0.04) efficient than pigs fed diets formulated with 20 to 160 ppm Mn from MnAA (Exp. 2). Color scores did not differ (P > 0.79) at the low inclusion (20 to 320 ppm Mn) levels used in Exp. 2; however, in Exp. 1, the LM from pigs fed Mn tended to receive higher (P = 0.10) American color scores than that of pigs fed the control diet, and Japanese color scores were higher for the LM from pigs fed diets containing 350 ppm Mn from MnAA than 350 Mn from ppm MnSO4 or 700 ppm Mn from MnAA (source x inclusion level; P = 0.04; Exp. 2). Chops of pigs fed 350 ppm Mn from MnAA were darker than the LM of pigs fed 350 ppm Mn from MnSO4, and 700 ppm Mn from MnAA diets (source x inclusion level; P = 0.03; Exp. 1), but L* values were not (P = 0.76) affected by lower MnAA inclusion levels (Exp. 2). Even though the LM tended to became redder as dietary MnAA inclusion level increased from 20 to 320 ppm Mn (linear effect; P < 0.10), a* values were not (P = 0.71) altered by including 350 or 700 ppm Mn (Exp. 1). Chops of pigs fed MnAA had lower cooking losses (P = 0.01) and shear force values (P = 0.07) after 2 d of aging than did chops from pigs fed diets formulated with MnSO4. Results from these experiments indicate that feeding 320 to 350 ppm Mn from MnAA during the growing-finishing period may enhance pork quality without adversely affecting pig performance or carcass composition.     

Assessment of energy content of low-solubles corn distillers dried grains and effects on growth performance, carcass characteristics, and pork fat quality in growing-finishing pigs

Two studies were conducted to assess the energy content of low-solubles distillers dried grains (LS-DDG) and their effects on growth performance, carcass characteristics, and pork fat quality in grow-finish pigs. In Exp. 1, 24 barrows (Yorkshire-Landrace × Duroc; 80 to 90 d of age) in 2 successive periods were assigned to 1 of 6 dietary treatments. In individual metabolism stalls, pigs were fed a corn-soybean meal diet (control); control replaced by 30, 40, or 50% LS-DDG; or control replaced by 30 or 40% distillers dried grains with solubles (DDGS) at 3% of their initial BW for 12 d. All diets contained 0.25% CrO(2). During the 5-d collection period, feces and urine were collected from each pig. Feed, feces, and urine were analyzed for DM, GE, and N concentrations, and feed and feces were analyzed for Cr content. The ME content of LS-DDG (2,959 ± 100 kcal/kg of DM) was similar to that determined for DDGS (2,964 ± 81 kcal/kg of DM). In Exp. 2, 216 Yorkshire-Landrace × Duroc pigs were blocked by initial BW (18.8 ± 0.76 kg) and assigned to 1 of 24 pens (9 pigs/pen). Pens within block were allotted to 1 of 3 dietary treatments (8 pens/treatment) in a 4-phase feeding program: a corn-soybean meal control (control), control containing 20% LS-DDG, or control containing 20% DDGS. Treatment had no effect on final BW, ADG, ADFI, or HCW. Pigs fed LS-DDG had similar G:F (0.367) compared with pigs fed DDGS (0.370), but tended (P = 0.09) to have decreased G:F compared with pigs fed the control (0.380; pooled SEM = 0.004). Dressing percent was less (P < 0.01) for pigs fed LS-DDG (72.8%) and DDGS (72.8%) compared with the control (73.8%; pooled SEM = 0.22). Pigs fed LS-DDG (54.8%) had greater (P = 0.02) carcass lean compared with pigs fed DDGS (53.4%), but were similar to pigs fed control (54.1%; pooled SEM = 0.33). Bellies from pigs fed DDGS (12.9°) were softer (P < 0.01) than those from pigs fed control (17.7°; pooled SEM = 1.07) as determined by the belly flop angle test. Feeding LS-DDG (14.1°) tended (P < 0.10) to create softer bellies compared with control-fed pigs. The PUFA content of belly fat was reduced (P < 0.01) by LS-DDG (14.0%) compared with DDGS (15.4%), but was increased (P < 0.05) compared with pigs fed the control (9.4%; pooled SEM = 0.34). In conclusion, LS-DDG and DDGS had similar ME values and inclusion of 20% LS-DDG in diets for growing-finishing pigs supports ADG and ADFI similar to that of diets containing 20% DDGS, and may reduce negative effects on pork fat compared with DDGS.     

Effects of adding fiber sources to reduced-crude protein,amino acid-supplemented diets on nitrogen excretion,growth performance,and carcass traits of finishing pigs

Two experiments were conducted to evaluate the effects of adding fiber sources to reduced-crude protein (CP), amino acid-supplemented diets on N excretion, growth performance, and carcass traits of growing-finishing pigs. In Exp. 1, six sets of four littermate barrows (initial weight = 36.3 kg) were allotted randomly to four dietary treatments to determine N balance and slurry composition. Dietary treatments were: 1) fortified corn-soybean meal, control, 2) as fortified corn-soybean meal with CP lowered by 4 percentage units and supplemented with lysine, threonine, methionine, tryptophan, isoleucine, and valine (LPAA), 3) same as Diet 2 plus 10% soybean hulls, and 4) same as Diet 2 with 10% dried beet pulp. Nitrogen intake, absorption, and retention (g/d) were reduced (P < 0.04) in pigs fed the low- protein diets, but they were not affected (P > 0.10) by addition of fiber sources to the LPAA diet. However, N absorption, as a percentage of intake, was not affected (P > 0.10) by dietary treatment. Nitrogen retention, expressed as a percentage of N intake, was increased (P < 0.02) in pigs fed the low-protein diets, but it was not affected by fiber addition to the LPAA diet. Urinary and total N excretion was reduced (P < 0.01) by 50 and 40%, respectively, in pigs fed the low- protein diets, but it was not affected (P > 0.10) by fiber addition. However, fiber addition to the LPAA diet tended to result in a greater proportion of N excreted in the feces than in the urine. Slurry pH, ammonium N content, and urinary urea N excretion were reduced (P < 0.10) in pigs fed LPAA, and a further reduction (P < 0.06) in slurry ammonium N content and urinary urea N was observed with fiber addition. Also, fiber addition to the LPAA diet increased (P < 0.02) slurry VFA concentrations. In Exp. 2, 72 pigs were blocked by body weight and sex and allotted randomly to three dietary treatments that were similar to those in Exp. 1, with a corn-soybean meal control diet, LPAA diet, and a LPAA diet with 10% soybean hulls. Pigs were fed the diets from 28.6 to 115 kg, and all pigs were killed for collection of carcass data. Growth performance and most carcass traits were not affected (P > 0.10) by dietary treatment. These data suggest that reducing CP with amino acid supplementation markedly decreased N excretion without influencing growth performance. Fiber addition to a LPAA diet had little effect on overall N balance or growth performance, but tended to further reduce slurry ammonium N concentration and increase volatile fatty acid concentrations.     

Effects of betaine, pen space, and slaughter handling method on growth performance, carcass traits, and pork quality of finishing barrows

An experiment was conducted to determine the effects of betaine, pen space, and preslaughter handling method on growth, carcass traits, and pork quality of finishing barrows. For the growth trial, a 2 x 2 factorial arrangement of treatments was used: betaine (0 or 0.250%) and(or) pen space (m2/pig; adequate, 0.035 BW0.67 kg, or inadequate, 0.025 BW0.67 kg). Each treatment was replicated five times with four barrows per replicate. At trial termination, two barrows from each pen were selected to receive either minimal or normal preslaughter handling. Reducing pen space decreased (P < 0.05) overall ADG and gain:feed and tended (P = 0.12) to decrease overall ADFI. Betaine had no affect (P > 0.10) on overall ADG, ADFI, or gain:feed. Pigs fed betaine had decreased (P < 0.10) carcass length. Other carcass and ham measurements were not affected (P > 0.10) by betaine. Pigs with inadequate pen space had increased (P < 0.10) ultimate pH, subjective color, cooking loss (fresh and frozen chop), and shear force but decreased rectal temperature, loin muscle CIE L*, biceps femoris CIE b*, and drip loss. Pigs subjected to minimal preslaughter handling had decreased (P < 0.10) rectal temperature, plasma cortisol, loin muscle CIE b*, and fresh chop total loss (drip + cooking loss). Pigs fed betaine had increased (P < 0.01) initial pH and decreased (P < 0.10) drip loss (fresh chop). Cooking loss and total loss (frozen chop) were decreased in pigs fed betaine with adequate pen space but increased in pigs fed betaine with inadequate pen space (betaine x pen space, P < 0.01). Pigs fed betaine may have improved pork quality.     

Assessment of chromium tripicolinate supplementation and dietary energy level and source on growth, carcass, and blood criteria in growing pigs

Two experiments were conducted to evaluate potential interactive effects of supplemental Cr and dietary energy supply in growing pigs. Experiment 1 used 36 individually penned barrows, 25 to 65 kg, in a 2 x 3 factorial arrangement of supplemental Cr (0 or 200 ppb) and energy level (70, 80, or 90% of ME requirement). A corn-soybean meal basal diet was designed to supply all protein, mineral, and vitamin needs and 70% of the estimated ME need at 70% of ad libitum feed intake. Additional energy to 80% or 90% of the ME requirement was provided by a cornstarch/corn oil blend. In Exp. 2, 30 individually penned barrows, 23 to 68 kg, were used in a 2 x 4 factorial arrangement of supplemental Cr (0 or 200 ppb) and added energy source (none, cornstarch, corn oil, or choice white grease) with basal diets identical to Exp. 1. The various energy sources were added to 90% of the ME requirement. In both experiments, growth data were collected over a 50-d period and pigs were killed at 70.1 kg. Increasing energy levels increased (linear, P < 0.01) ADG, average backfat thickness, 10th rib backfat thickness, and cooler shrink and decreased (linear, P < 0.01) longissimus muscle area in Exp. 1. Carcass composition increased (linear, P < 0.01) in lipid and decreased in protein, water, and protein:lipid ratio in response to increasing ME levels. Similar results were observed in Exp. 2 in response to added energy, regardless of the energy source used. In response to ME, linear increases (P < 0.05) in plasma insulin concentration before feeding and after feeding were observed in Exp. 1. In Exp. 2, plasma insulin concentration was lower for the basal diet before feeding (P < 0.05) and higher for the starch diet after feeding (P < 0.01); insulin:glucose ratio increased (P < 0.01) after feeding for starch compared to oil and fat. No consistent effect of Cr or Cr x ME level on performance or carcass was observed (P > 0.10) in these experiments. Similarly, no Cr effect or Cr x ME interaction (P > 0.10) was observed in plasma glucose or insulin levels. Dietary energy levels markedly affected growth criteria in growing pigs (23 to 68 kg) in these experiments, as anticipated, but supplemental Cr was without effect on performance or carcass responses.     

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.     

The influence of dietary field peas (Pisum sativum L.) on pig performance, carcass quality, and the palatability of pork

An experiment was conducted to test the hypothesis that field peas may replace soybean meal in diets fed to growing and finishing pigs without negatively influencing pig performance, carcass quality, or pork palatability. Forty-eight pigs (initial average BW 22.7 +/- 1.21 kg) were allotted to 1 of 3 treatments with 2 pigs per pen. There were 8 replications per treatment, 4 with barrows and 4 with gilts. The treatments were control, medium field peas, and maximum field peas. Pigs were fed grower diets for 35 d, early finisher diets for 35 d, and late finisher diets for 45 d. Pigs receiving the control treatment were fed corn-soybean meal diets. All diets fed to pigs receiving the medium field peas treatment contained 36% field peas and varying amounts of corn; soybean meal was also included in the grower and the early finisher diets fed to pigs on this treatment. In contrast, no soybean meal was included in diets fed to pigs on the maximum field peas treatment, and field peas were included at concentrations of 66, 48, and 36% in the grower, early finisher, and late finisher diets, respectively. Pig performance was monitored within each phase and for the entire experimental period. At the conclusion of the experiment, carcass composition, carcass quality, and the palatability of pork chops and pork patties were measured. Results showed that there were no effects of dietary treatments on ADFI, ADG, or G:F. Likewise, there were no differences in carcass composition among the treatment groups, but gilts had larger (P = 0.001) and deeper (P = 0.003) LM, less backfat (P = 0.007), and a greater (P = 0.002) lean meat percentage than barrows. The pH and marbling of the LM, and the 10th rib backfat were not influenced by treatment, but there was a trend (P = 0.10) for more marbling in barrows than in gilts. The subjective color scores (P = 0.003) and the objective color score (P = 0.06) indicated that dietary field peas made the LM darker and more desirable. Pork chops from pigs fed field peas also had less (P = 0.02) moisture loss compared with chops from pigs fed the control diet. Treatment or sex did not influence palatability of pork chops or pork patties. In conclusion, field peas may replace all of the soybean meal in diets fed to growing and finishing pigs without negatively influencing pig performance, carcass composition, carcass quality, or pork palatability.     

Growth performance of 20- to 50-kilogram pigs fed low-crude-protein diets supplemented with histidine, cystine, glycine, glutamic acid, or arginine

The purpose of this investigation was to compare the growth performance of grower pigs fed low-CP, corn-soybean meal (C-SBM) AA-supplemented diets with that of pigs fed a positive control (PC) C-SBM diet with no supplemental Lys. Five experiments were conducted with Yorkshire crossbred pigs, blocked by BW (average initial and final BW were 21 and 41 kg, respectively) and assigned within block to treatment. Each treatment was replicated 4 to 6 times with 4 or 5 pigs per replicate pen. Each experiment lasted 28 d and plasma urea N was determined at the start and end of each experiment. All diets were formulated to contain 0.83% standardized ileal digestible Lys. All the experiments contained PC and negative control (NC) diets. The PC diet contained 18% CP and was supplemented with only DL-Met. The NC diet contained 13% CP and was supplemented with L-Lys, DL-Met, L-Thr, and L-Trp. The NC + Ile + Val diet was supplemented with 0.10% Val + 0.06% Ile. The NC + Ile + Val diet was supplemented with either His (Exp. 1), Cys (Exp. 2), Gly (Exp. 2, 3, and 4), Glu (Exp. 3), Arg (Exp. 4), or combinations of Gly + Arg (Exp. 4 and 5) or Gly + Glu (Exp. 5). Treatment differences were considered significant at P < 0.10. In 3 of the 4 experiments that had PC and NC diets, pigs fed the NC diet had decreased ADG and G:F compared with pigs fed the PC diet. The supplementation of Ile + Val to the NC diet restored ADG in 4 out of 5 experiments. However, G:F was less than in pigs fed the PC diet in 1 experiment and was intermediate between the NC and PC diets in 3 experiments. Pigs fed supplemental Ile + Val + His had decreased G:F compared with pigs fed the PC. Pigs fed supplemental Cys to achieve 50:50 Met:Cys had decreased G:F compared with pigs fed the PC. Pigs fed Ile + Val + 0.224% supplemental Gly had similar ADG, greater ADFI, and decreased G:F compared with pigs fed the PC. Pigs fed Ile + Val + 0.52% supplemental Gly had ADG and G:F similar to that of pigs fed the PC. Pigs fed supplemental Glu had decreased G:F compared with pigs fed the PC. Pigs fed Ile + Val + 0.48% supplemental Arg had decreased G:F compared with pigs fed the PC. Pigs fed the diet supplemented with Gly + Arg had ADG and G:F similar to pigs fed the PC. Pigs fed the low-CP diets had reduced plasma urea N compared with pigs fed PC. The results of these experiments indicate that supplementing Gly or Gly + Arg to a low-CP C-SBM diet with 0.34% Lys, Met, Thr, Trp, Ile, and Val restores growth performance to be similar to that of pigs fed a PC diet with no Lys supplementation.     

Valine and soleucine requirement of 20- to 45-kilogram pigs

Three experiments were conducted to determine the Val and Ile requirements in low-CP, corn-soybean meal (C-SBM) AA-supplemented diets for 20- to 45-kg pigs. All experiments were conducted for 26 to 27 d with purebred or crossbred barrows and gilts, which were blocked by initial BW. Treatments were replicated with 5 or 6 pens of 3 or 4 pigs per pen. At the beginning of Exp. 1 and the end of all experiments, blood samples were obtained from all pigs to determine plasma urea N (PUN) concentrations. All diets were C-SBM with 0.335% supplemental Lys to achieve 0.83% standardized ileal digestible (SID) Lys, which is the Lys requirement of these pigs. In Exp. 1, 0, 0.02, 0.04, 0.06, 0.08, or 0.10% L-Val was supplemented to achieve 0.51, 0.53, 0.55, 0.57, 0.59, or 0.61% dietary SID Val, and Thr, Trp, Met, and Ile were supplemented to maintain Thr:Lys, Trp:Lys, TSAA:Lys, and Ile:Lys ratios of 0.71, 0.20, 0.62, and 0.60, respectively. Also, supplemental Gly and Glu were added to all diets to achieve 1.66% Gly + Ser and 3.28% Glu, which is equal to the Gly + Ser and Glu content of a previously validated positive control diet that contained no supplemental AA. Treatment differences were considered significant at P < 0.10. Valine addition increased ADG, ADFI, and G:F in pigs fed 0.51 to 0.59% SID Val (linear, P < 0.08), but ADG and ADFI were decreased at 0.61% SID Val (quadratic, P ≤ 0.10). On the basis of ADG and G:F, the SID Val requirement is between 0.56 and 0.58% in a C-SBM diet supplemented with AA. In Exp. 2 and 3, 0, 0.02, 0.04, 0.06, or 0.08% L-Ile was supplemented to achieve 0.43, 0.45, 0.47, 0.49, or 0.51% dietary SID Ile, and Thr, Trp, Met, and Ile were supplemented to maintain Thr:Lys, Trp:Lys, TSAA:Lys, and Val:Lys ratios of 0.71, 0.20, 0.62, and 0.74, respectively. Also, supplemental Gly and Glu were added to achieve 1.66% Gly + Ser and 3.28% Glu as in Exp. 1. Data from Exp. 2 and 3 were combined and analyzed as 1 data set. Daily BW gain, ADFI, and G:F were not affected by Ile additions to the diet; however, ADFI was decreased among pigs fed the diet with 0.45% SID Ile (P < 0.10) compared with pigs fed the 0.43% SID Ile diet. Broken-line analysis requirements could not be estimated for the combined data from Exp. 2 or 3. The results of this research indicate that the SID Val requirement is between 0.56 to 0.58% (0.67 to 0.70 SID Val:Lys), and the Ile requirement is adequate at 0.43% SID Ile (0.52 SID Ile:Lys) for 20- to 45-kg pigs.