甘露寡糖对保育猪的营养与保健作用

大量研究表明,甘露寡糖(MOS)通过积极影响断奶仔猪的肠道微生物菌群和肠道形态结构,加速由于断奶饥饿应激或采食固体饲料中抗原受损伤的肠黏膜上皮的修复,有助于保持仔猪断奶后肠道的完整性和消化吸收功能。在免疫反应方面,MOS通过促进抗原提呈增强断奶仔猪的抗病性,从而增强从先天性免疫应答向适应性免疫应答的转变。     

天然生长促进剂Alquernat Nebsui对保育猪生长性能的影响

为研究天然生长促进剂Alquernat Nebsui对保育猪生长性能的影响,本研究选用杜长大杂交30日龄健康断乳仔猪180头,经免疫接种和驱虫后投入试验,按公母各半,体重日龄相近随机分成3组,每组3个重复,每个重复20头猪。试验从30日龄断乳猪开始,试验期30 d,空白对照组为日粮不添加任何添加剂,试验组为添加一定量的天然生长促进剂Alquernat Nebsui,抗生素组为添加一定量的抗生素,进行生长试验研究。结果显示:与对照组相比,抗生素组、Alquernat Nebsui均能显著提高仔猪的日采食量(P<0.05),其中抗生素组的效果大于Alquernat Nebsui组;与对照组相比抗生素组、Alquernat Nebsui组的日增重均极显著增加(P<0.01),说明天然生长促进剂Alquernat Nebsui可以提高对饲料的转化率、提高生产性能。     

Effects of increasing tryptophan intake on growth and physiological changes in nursery pigs

Tryptophan (Trp) as a precursor of serotonin (5-hydroxytryptamine, 5-HT) has long been used to extenuate aggressive behavior and control stress of humans as well as several farm animals. This study was conducted to determine the effect of supplemental L-Tryptophan (L-Trp) on growth, cerebral 5-HT concentration, stress hormone concentration, oxidative stress status, and behavior response of pigs under social stress, and also to determine an optimal daily total Trp intake that would benefit nursery pigs under social stress. Seventy two individually housed barrows at 6 wk of age were randomly allotted to 6 treatments with supplementation of 0, 2, 4, 6, 8, or 10 g L-Trp/kg to corn and soybean meal-based feedstuffs. Pigs were fed assigned feedstuffs for 15 d. Body weight was measured on d 0, 5, 10, and 15. Saliva and blood were collected on d 5, 10, and 15. On d 5 and 10, all 12 pigs in each treatment were paired in 6 new pens to record behavior for a 2-d period and returned to original individual pens. On d 15, pigs were euthanized to obtain hypothalamus. During the first 5 d, ADG and G:F increased (linear, P < 0.01) with increasing supplemental L-Trp. During the entire 15 d, ADG and G:F increased (linear, P = 0.01 and P < 0.01, respectively) with increasing supplemental L-Trp. Estimates of the daily total Trp intake based on ADG on d 15 were 10.8 g/d (P < 0.01; R(2) = 0.16) using a 1-slope broken-line analysis. Hypothalamic 5-HT and 5-hydroxyindoleacetic acid increased (linear, P < 0.01 and P = 0.03, respectively) with increasing supplemental L-Trp. Malonedialdehyde in plasma and hypothalamus, as well as salivary cortisol, on d 15 decreased (linear, P = 0.01, P < 0.01, and P < 0.01, respectively) with increasing supplemental L-Trp. Plasma urea nitrogen decreased (linear, P < 0.01) with increasing supplemental L-Trp. Increasing supplemental L-Trp affected pig behaviors during the first 2-d observation period by decreasing (quadratic, P = 0.04) lying, decreasing (linear, P = 0.04) sitting, and increasing (linear, P = 0.02) drinking. Overall, supplementation of L-Trp improved growth performance of 6 wk-old nursery pigs under social stress in association with increasing hypothalamic 5-HT production, reducing stress hormone concentrations, decreasing lipid peroxidation, increasing drinking, and reducing sitting and lying. Increase in BW gain of nursery pigs under social stress was maximal when daily total Trp intake was 10.8 g.     

Effects of frequent out-of-feed events on growth performance of nursery and grow-finish pigs

Two experiments were conducted to evaluate effects of out-of-feed events on nursery and grow-finish pig performance. An out-of-feed event is a period of time that pigs do not have access to feed as a result of late feed delivery or bridging in bulk bins, feed lines, or feeders. In these studies, we created an out-of-feed event by removing the feeders from pens or preventing access to the feeder. In Exp. 1, 190 pigs (initially 6.4 +/- 1.6 kg and 21 +/- 3 d of age) were used in a 35-d growth study. Treatments involved a 20-h feed withdrawal for 1, 2, or 3 randomly selected times or a control treatment where feeders were never withdrawn. Feeders were withdrawn on d 11 for pigs with 1 out-of-feed event, d 8 and 23 for pigs with 2 out-of-feed events, and d 9, 14, and 20 for pigs with 3 out-of-feed events. There was a treatment (P < 0.06) effect only during weeks in which an out-of-feed event occurred. Growth rate was lower (P < 0.05) for pigs with 1 out-of-feed event (d 11) compared with control in the d 8 to 14 period. During the same period, those pigs with the first of 2 (d 8) or 3 (d 9) out-of-feed events had intermediate ADG. In the d 15 to 21 period, only pigs with the second and third of 3 out-of-feed events (d 15 and 20) had lower growth performance compared with control pigs, whereas growth performance was similar to the control for those with 1 or 2 out-of-feed events. Pigs with 3 out-of-feed events had greater ADG and G:F (P < 0.05) compared with the other 3 treatments for the d 22 to 28 period. For the overall study (d 0 to 35), there were no differences (P > 0.86) in growth performance among pigs with 0, 1, 2, or 3 out-of-feed events. In Exp. 2, 479 pigs (initially 41.6 +/- 4 kg) were used in an 85-d growth study. Treatments involved feed withdrawal (20 h) weekly for the duration of the study; feed withdrawn weekly from d 45 to 85; or a control treatment where pigs had access to feed for the duration of the experiment. Feed withdrawal occurred on a randomly selected day with the exception of Saturday, Sunday, or a day before a weigh day (usually a Thursday every other week). From d 0 to 45, 46 to 85, and the overall d 0 to 85 period, there were no differences (P > 0.12) in ADG, ADFI, G:F, or average final BW among treatments. Results suggest that out-of-feed events of 20 h or less have no long-term detrimental effects on growth performance in nursery or grow-finish pigs.     

Effects of soybean meal particle size on growth performance of nursery pigs

We used 360 nursery pigs (35 +/- 3 d of age) in two 21-d growth assays to determine the effects of soybean meal particle size on growth performance. In both trials, there were six pigs per pen and 10 pens per treatment. Pigs were weaned on d 21 and fed the same phase I diet for 7 d after weaning, followed by a phase II diet from d 7 to 14. On d 14, all pigs were weighed and randomly allotted to one of three dietary treatments. Experimental diets contained 61.9% corn, 34.4% soybean meal, and 3.7% vitamins and minerals. In Exp. 1, 90 barrows and 90 gilts (9.2 +/- 2.3 kg BW) were fed diets containing extruded-expelled soybean meal ground to 965, 742, or 639 microm, which resulted in whole-diet particle sizes of 728, 719, and 697 microm, respectively. Reducing extruded-expelled soybean meal particle size from 965 or 742 to 639 microm in the diet did not affect (P > 0.10) ADG (541, 538, and 542 g/d), ADFI (886, 875, and 855 g/d; as-fed basis), or gain:feed ratio (0.61, 0.61, 0.64), respectively. In Exp. 2, 90 barrows and 90 gilts (9.9 +/- 2.6 kg BW) were fed diets containing solvent-extracted soybean meal ground to 1,226, 797, or 444 microm, which resulted in whole-diet particle sizes of 732, 681, and 629 microns, respectively. Like Exp. 1, reducing particle size of solvent-extracted soybean meal did not affect (P > 0.10) ADG (482, 487, and 484 g/d), ADFI (738, 742, and 736 g/d; as-fed), or gain:feed (0.65, 0.65, and 0.65). Reducing particle size of extruded-expelled soybean meal or solvent-extracted soybean meal increased the angle of repose (maximum degree at which a pile of material retains its slope), indicating that as particle size decreased, flowability characteristics decreased. However, the angle of repose of the complete diets was greater than that for the soybean meals, which indicates that decreasing the particle size of soybean meal had minimal effects on flow characteristics of the complete diet. Previous research has shown that decreasing grain particle size improves digestibility and feed efficiency, and decreased soybean meal particle size has resulted in improved amino acid digestibility. However, the results of our experiments suggest decreasing particle size of either extruded-expelled soybean meal or solvent-extracted soybean meal does not affect nursery pig growth performance.     

Effects of betaine on growth, carcass characteristics, pork quality, and plasma metabolites of finishing pigs

An experiment was conducted to determine the effect of dietary betaine (0, 0.125, 0.250, or 0.500%) on growth, carcass traits, pork quality, plasma metabolites, and tissue betaine concentrations of cross-bred finishing pigs. Four replications of three pigs (two barrows and one gilt) each were used for each treatment. The basal diet contained 0.85 (69 to 88 kg BW) or 0.65% Lys (88 to 115 kg BW). Overall ADG and gain:feed were not affected (P > 0.10) by betaine, but overall ADFI was decreased (quadratic, P < 0.05; 0 vs betaine, P < 0.01) by betaine; pigs fed 0.250% betaine had the lowest ADFI. Loin muscle area, average back-fat, dressing percentage, percentage lean, total fat, lean:fat, and leaf fat weight were not affected (P > 0.10) by betaine. Tenth-rib backfat thickness was decreased (quadratic, P < 0.05; 0 vs betaine, P < 0.05); pigs fed 0.250% betaine had the lowest 10th-rib backfat thickness. Carcass length was increased (linear, P < 0.05; 0 vs betaine, P < 0.10) as the level of betaine was increased. Fat-free lean, lean gain per day, ham weight, ham fat-free lean, and ham percentage lean were increased (quadratic, P < 0.10), but percentage fat, total ham fat, percentage ham fat, and butt-fat thickness were decreased (quadratic, P < 0.10); these traits were respectively highest or lowest in pigs fed 0.250% betaine. Thaw loss and 24-h pH were increased (quadratic, P < 0.10; 0 vs betaine, P < 0.05) and cook loss was decreased (linear, P < 0.05) in pigs fed betaine. The CIE L* value for the biceps femoris was decreased (quadratic, P < 0.10; 0 vs betaine, P < 0.10); pigs fed 0.250% betaine had the lowest CIE L* value. Subjective color, firmness-wetness, marbling, percentage moisture and bound water of the loin muscle, and shear force were not affected (P > 0.10) by betaine. Betaine was not detectable (< 0.07 mg/g) in the loin muscle of pigs fed 0% betaine, but betaine was detectable and relatively constant in pigs fed 0.125, 0.250, or 0.500% betaine (0.22, 0.17, and 0.21 mg/g, respectively). Plasma urea N, total protein, albumin, triglycerides, and HDL cholesterol concentrations were not affected (P > 0.10). Plasma total cholesterol (linear, P < 0.10) and NEFA (quadratic, P < 0.10) were increased in pigs fed betaine. Betaine improved carcass traits when provided at 0.250% of the diet and improved some aspects of pork quality.     

Absorption and metabolism of alpha-ketoglutarate in growing pigs

The portal appearance of enteral alpha-ketoglutarate (AKG) and the effect of enteral or parenteral AKG on portal net appearance of glucose, short-chain fatty acids, alanine, aspartate, glutamate, glutamine, proline and insulin were investigated in three growing pigs. During the experimental samplings the pigs were fed hourly with a standard feed mix with 5% glucose (control), 5% AKG (enteral) or no feed additive but continuously infused with AKG into the mesenteric vein in an amount equivalent to 5% of feed intake (parenteral). The arterial plasma concentration of AKG increased (p < 0.05) following both enteral (from 16+/-2 to 22+/-3 micromol/l) and parenteral (from 16+/-2 to 425+/-27 micromol/l) administration of AKG. With the enteral treatment 4+/-1% of the AKG could be accounted for in the portal vein, however, with the parenteral treatment 86+/-5% could be accounted for in the portal vein. The arterial plasma concentration of proline increased (p < 0.05) with the enteral treatment (365 +/- 3 to 443 +/- 39 micromol/l), but was not affected by the parenteral treatment (p > 0.10). The plasma concentration glutamine decreased (p < 0.05) with the parenteral treatment only. The portal net appearance of proline showed a numerical increase with the enteral treatment but no other affects on arterial concentrations or portal net appearance were found. A small accompanying study showed that only small amounts of enteral AKG was present in the small intestine. It was therefore concluded that enteral AKG has a low availability to peripheral tissues either because it is absorbed and metabolized in the stomach and duodenum or because it is metabolized by microbes in the stomach. The study showed that AKG is metabolized differently following enteral and parenteral application in growing pigs.     

Comparison of wheat gluten and spray-dried animal plasma in diets for nursery pigs

Five experiments were conducted to determine the effects of different wheat gluten (WG) sources (Source 1 = enzymatically hydrolyzed, Source 2 = nonmodified ring-dried, Source 3 = spray-dried, and Source 4 = flash-dried) on growth performance of nursery pigs compared with soybean meal (SBM), spray-dried animal plasma (SDAP), or other specialty protein sources. In Exp. 1, pigs (n = 220, initially 6.1 +/- 2.5 kg) were fed a control diet containing (as-fed basis) 6% SDAP or WG Source 1 or 2. The WG and l-lysine*HCl replaced 50 or 100% of the SDAP. From d 0 to 21, increasing WG (either source) decreased ADG and ADFI (linear, P < 0.01), but improved (linear, P < 0.02) G:F. In Exp. 2, pigs (n = 252, initially 6.2 +/- 3.0 kg) were fed a negative control diet containing no SDAP or WG, diets containing (as-fed basis) 9% WG Source 1 or 5% SDAP, or combinations of WG and SDAP where WG and l-lysine*HCl replaced 25, 50, or 75% of SDAP. From d 0 to 14, pigs fed increasing WG had decreased ADG (linear, P < 0.05). In Exp. 3, pigs (n = 240, initially 7.0 +/- 2.5 kg) were fed a negative control diet, a diet containing (as-fed basis) either 3, 6, 9, or 12% WG Source 3, or a positive control diet containing 5% SDAP. The diets containing 9% WG and 5% SDAP had the same amount of SBM. From d 0 to 7, pigs fed 5% SDAP had greater (P < 0.04) ADG than pigs fed the diet containing 9% WG. From d 0 to 14, increasing WG had no effect on ADG, ADFI, or G:F. In Exp. 4, pigs (n = 200, initially 6.0 +/- 2.4 kg) were fed a negative control diet, the control diet with (as-fed basis) 4.5 or 9.0% WG Source 1, or the control diet with 2.5 or 5.0% SDAP. Diets containing WG and SDAP had similar SBM levels. From d 0 to 7 and 0 to 14, increasing SDAP tended to improve (linear, P < 0.06) ADG, but increasing WG had no effect. In Exp. 5, 170 barrows and gilts (initially 7.5 +/- 2.8 kg) were used to determine the effects of WG Source 1 and 4 compared with select Menhaden fish meal or spray-dried blood cells and a negative control diet (SBM) on the growth performance of nursery pigs from d 5 to 26 postweaning (d 0 to 21 of experiment). No differences were found in ADG or G:F, but pigs fed the diet containing (as-fed basis) 2.5% spray-dried blood cells had greater ADFI than pigs fed the negative control from d 0 to 21. Wheat gluten source had no effect on ADG, ADFI, or G:F. The results of these studies suggest that increasing WG in diets fed immediately after weaning did not improve growth performance relative to SBM or SDAP.     

Effect of medium-chain triglycerides on growth performance,nutrient digestibility,plasma metabolites and antioxidant capacity in weanling pigs

The aim of this study was to investigate the effect of medium-chain triglycerides(MCTs) on growth performance, nutrient digestibility, plasma metabolites and antioxidant capacity in weanling pigs. A total of 160 weanling(Duroc × Landrace x Yorkshire) pigs(age: 21 ± 1 d; body weight: 7.50 ± 0.28 kg) were randomly allotted to 4 treatments, receiving the following diets for 28 d: control diet [containing 3.5%soybean oil(SO)], MCT1 diet(containing 0.7% MCTs and 2.8% SO), MCT2 diet(containing 1.4% MCTs and2.1% SO) and MCT3 diet(containing 2.1% MCTs and 1.4% SO). Dietary inclusion of MCTs improved the average daily gain and feed efficiency(FE) of pigs compared with the control during the first 2 weeks post-weaning(P 0.05). A similar positive effect was also observed for the overall FE in MCT2 group(P 0.05). Compared with the control, apparent total tract digestibility(ATTD) of ether extract was improved by MCT2 and MCT3 treatment from day 12-14 post-weaning(P 0.05). In addition, MCT2 treatment also exerted a beneficial effect on the ATTD of dry matter(P 0.05). The increased total protein concentration and decreased urea nitrogen and malondialdehyde levels of plasma were observed in both MCT2 and MCT3 groups on day 14 post-weaning(P 0.05). In conclusion, MCTs could improve growth performance, nutrients utilization, and antioxidant ability of weanling piglets.     

Effect of chromium propionate on growth, carcass traits, pork quality, and plasma metabolites in growing-finishing pigs

Two experiments were conducted to determine the effects of dietary Cr, as Cr propionate, on growth, carcass traits, pork quality, and plasma metabolites in growing-finishing swine. Ninety-six crossbred gilts (Exp. 1; initial and final BW of 28 [SEM = 0.41] and 109 [SEM = 2.11] kg) or 144 PIC Cambrough 22 barrows (Exp. 2; initial and final BW of 26 [SEM = 0.39] and 111 [SEM = 2.52] kg) were allotted to six or four dietary treatments, respectively, with six replications and four (Exp. 1) or six (Exp. 2) pigs in each replicate pen blocked by weight in randomized complete block designs. The six dietary treatments for Exp. 1 were 1) corn-soybean meal (C-SBM), 2) C-SBM + 50 ppb Cr, 3) C-SBM + 100 ppb Cr, 4) C-SBM + 200 ppb Cr, 5) C-SBM low NE diet, and 6) C-SBM low NE diet + 200 ppb Cr. The four dietary treatments for Exp. 2 were C-SBM with 0, 100, 200, or 300 ppb Cr. Growth, carcass traits, and plasma metabolite (collected on d 29 and at each phase change) data were taken at the end of both experiments and pork quality data were taken at the end of Exp. 1. There was no effect (P > 0.10) on overall growth performance when pigs were fed graded levels of Cr (Exp. 1 and 2) or Cr in the positive control or low NE diets (Exp. 1). Longissimus muscle area, ham weight, ham fat-free lean, and total carcass lean were increased in pigs fed 200 ppb in the positive control diets but decreased in pigs fed 200 ppb Cr in the low NE diets (Cr x NE, P < 0.08). There was no effect of Cr concentration (P > 0.10) on carcass traits in Exp. 2. In Exp. 1, cook loss of a fresh or a frozen chop was decreased (P < 0.10) by 200 ppb Cr. In Exp. 1, NEFA concentration was decreased (P < 0.05) in pigs fed Cr in the positive control or low NE diets during the early-finishing period. In Exp. 2, the addition of Cr decreased NEFA (quadratic, P < 0.09) and plasma urea N (linear, P < 0.02) concentrations and tended to increase total cholesterol and high density lipoproteins (quadratic, P < 0.09). In these experiments, Cr propionate had no effect on overall growth performance, variable effects on carcass traits and plasma metabolites, and some positive effects on pork quality, especially water holding capacity of a fresh or frozen chop.     

The effects of pharmacological levels of zinc,diet acidification,and dietary crude protein on growth performance in nursery pigs

This experiment was conducted to evaluate potential replacements for pharmacological levels of Zn (provided by Zn oxide), such as diet acidification (sodium diformate) and low dietary crude protein (CP: 21 vs 18%) on nursery pig performance and fecal dry matter (DM). A total of 360 weaned pigs (Line 200 × 400, DNA, Columbus, NE; initially 5.90 ± 0.014 kg) were used in a 42-d growth study. Pigs were weaned at approximately 21 d of age and randomly assigned to pens (five pigs per pen). Pens were then allotted to one of eight dietary treatments with nine pens per treatment. Experimental diets were fed in two phases: phase 1 from weaning to day 7 and phase 2 from days 7 to 21, with all pigs fed the same common diet from days 21 to 42. The eight treatment diets were arranged as a 2 × 2 × 2 factorial with main effects of Zn (110 mg/kg from days 0 to 21 or 3,000 mg/kg from days 0 to 7, and 2,000 mg/kg from days 7 to 21), diet acidification, (without or with 1.2% sodium diformate), and dietary CP (21% or 18%, 1.40% and 1.35% in phases 1 and 2 vs. 1.20% standardized ileal digestible Lys, respectively). Fecal samples were collected weekly from the same three pigs per pen to determine DM content. No 2- or 3-way interactions (P > 0.05) were observed throughout the 42-d study for growth performance; however, there was a Zn × acidifier × CP interaction (P < 0.05) for fecal DM on day 7 and for the overall average of the six collection periods. Reducing CP without acidification or pharmacological levels of Zn increased fecal DM, but CP had little effect when ZnO was present in the diet. From days 0 to 21, significant (P < 0.05) main effects were observed where average daily gain (ADG) and gain:feed (G:F) increased for pigs fed pharmacological levels of Zn, sodium diformate, or 21% CP (P < 0.065). In the subsequent period (days 21 to 42) after the experimental diets were fed, there was no evidence of difference in growth performance among treatments. Overall (days 0 to 42), main effect tendencies were observed (P < 0.066) for pigs fed added Zn or sodium diformate from days 0 to 21, whereas pigs fed 21% CP had greater G:F than those fed 18% CP. Pig weight on day 42 was increased by adding Zn (P < 0.05) or acidifier (P < 0.06) but not CP. In summary, none of the feed additives had a major influence on fecal DM, but dietary addition of pharmacological levels of Zn or sodium diformate independently improved nursery pig performance.     

Valine requirement of nursery pigs

Six experiments were conducted to determine the true digestible valine requirement of 5- to 20-kg pigs. In Exp. 1, a valine-deficient diet for 5- to 10-kg pigs was developed and validated in terms of growth performance in response to supplemental L-valine. A different basal diet was validated for 10- to 20-kg pigs in Exp. 2. Both diets were demonstrated to be deficient in valine and to support performance equivalent to typical nursery diets when fortified with L-valine. In Exp. 3, true ileal digestibility of valine in the two basal diets was determined in eight pigs fitted with a simple T-cannula at the terminal ileum. Another four pigs received an enzymatically hydrolyzed casein-based diet to determine endogenous contributions to collected ileal digesta. The two diets were found to have true valine digestibilities of 82% (5- to 10-kg pigs) and 86% (10- to 20-kg pigs). In Exp. 4, 80 weaned pigs (5.8 kg) were offered the basal diet fortified with five incremental doses (0.08%) of L-valine. Weight gain increased quadratically (P < 0.05) with increasing levels of valine. Broken-line analysis revealed a true digestible valine requirement of 0.86 +/- 0.03%. In Exp. 5, the true digestible valine requirement of 10- to 20-kg pigs was estimated with 120 pigs (10.9 kg) using the second basal diet fortified with six incremental doses (0.05%) of L-valine. The data suggested a digestible valine requirement level of about 0.775%, which was reevaluated in Exp. 6, wherein pigs did not respond to levels of digestible valine higher than 0.775%. In conclusion, requirement estimates were 2.50 and 2.22 g of true digestible valine per megacalorie of ME for 5- to 10- and 10- to 20-kg pigs, respectively. These empirical estimates are in close agreement with recent estimates of the National Research Council Subcommittee on Swine Nutrition of 2.48 and 2.11 g of true digestible valine per megacalorie of ME, respectively.     

Effect of dietary L-carnitine on growth performance and body composition in nursery and growing-finishing pigs.

Two experiments were conducted to determine the effect of dietary L-carnitine on growth performance and carcass composition of nursery and growing-finishing pigs. In Exp. 1,216 weanling pigs (initially 4.9 kg and 19 to 23 d of age) were used in a 35-d growth trial. Pigs were blocked by weight in a randomized complete block design (six pigs per pen and six pens per treatment). Four barrows and four gilts were used to determine initial carcass composition. L-Carnitine replaced ground corn in the control diets to provide 250, 500, 750, 1,000, or 1,250 ppm. On d 35, three barrows and three gilts per treatment (one pig/block) were killed to provide carcass compositions. L-Carnitine had no effect (P > 0.10) on growth, percentages of carcass CP and lipid, or daily protein accretion. However, daily lipid accretion tended to decrease and then return to values similar to those for control pigs (quadratic P < 0.10) with increasing dietary L-carnitine. In Exp. 2, 96 crossbred pigs (initially 34.0 kg BW) were used to investigate the effect of increasing dietary L-carnitine in growing-finishing pigs. Pigs (48 barrows and 48 gilts) were blocked by weight and sex in a randomized complete block design (two pigs/pen and eight pens/treatment). Dietary L-carnitine replaced cornstarch in the control diet to provide 25, 50, 75, 100, and 125 ppm in grower (34 to 56.7 kg; 1.0% lysine) and finisher (56.7 to 103 kg; 0.80% lysine) diets. At 103 kg, one pig/pen was slaughtered, and standard carcass measurements were obtained. Dietary L-carnitine did not influence growth performance (P > 0.10). However, increasing dietary carnitine decreased average and tenth-rib back-fat (quadratic, P < 0.10 and 0.05), and increased percentage lean and daily CP accretion rate (quadratic, P < 0.05). Break point analysis projected the optimal dosage to be between 49 and 64 ppm of L-carnitine for these carcass traits. It is concluded that dietary carnitine fed during the nursery or growing-finishing phase had no effect on growth performance; however, feeding 49 to 64 ppm of L-carnitine during the growing-finishing phase increased CP accretion and decreased tenth-rib backfat.     

Fasting plasma hormones and metabolites in feral and domestic newborn pigs

Newborn Yorkshire and Ossabaw (feral) pigs were examined under thermoneutral conditions to determine whether survival rate during fasting differs between these breeds and whether any blood-borne factors are associated with improved survival. Newborn pigs were removed from the sow before suckling. Body composition was determined on 10 newborn Ossabaw and 12 newborn Yorkshire pigs. Another group of animals (eight Ossabaw, 12 Yorkshire) was fasted for 72 hr, with blood samples drawn at birth and 12 and 24 hr into fasting. Glucose, free fatty acid (FFA), growth hormone (GH), insulin, thyroxine (T4), triiodothyronine (T3), cortisol and glucagon concentrations were measured in plasma of fasted pigs. Concentrations of carcass lipid, dry matter and ash were higher in newborn Ossabaw pigs than in newborn Yorkshire pigs. Survival through 72 hr of fasting was lower among Yorkshire pigs. Yorkshire and Ossabaw pigs had similar concentrations of metabolites and hormones at birth, with the exceptions of lower plasma GH and higher T3 concentrations in Ossabaw pigs. Higher plasma T3 concentrations would indicate a greater potential for fatty acid oxidation. During fasting, Ossabaw pigs had lower plasma GH and T4 concentrations and higher glucagon and FFA concentrations. Increased survival among newborn Ossabaw pigs may have been due to increased availability of FFA during fasting, and to a greater potential for gluconeogenesis through increased oxidation of fatty acids and higher plasma glucagon concentrations. This would suggest that maternal treatments that would increase storage of fat and(or) increase the capacity for oxidation of fat in utero would improve survival of newborn pigs.     

标准回肠可消化色氨酸与赖氨酸比值对保育猪生长性能的影响

本研究的两个试验旨在评估保育猪最佳生长性能所需的标准回肠可消化(SID)色氨酸与赖氨酸的比值。试验配方确保赖氨酸作为第二限制性氨基酸。试验1中(饲养体重阶段为6~10 kg),255头保育仔猪(PIC 327×1050,初始体重为6.3±0.15kg,平均数±标准差)按栏重分为6个处理,每个处理7栏(每栏为1个重复),每栏饲养6至7头仔猪。6个处理的SID赖氨酸水平均为1.30%,但SID色氨酸与赖氨酸比值分别为14.7%、16.5%、18.4%、20.3%、22.1%和24.0%,试验为期14天。试验2中(饲养体重阶段为11~20 kg),1088头保育仔猪(PIC 337×1050,初始体重11.2±1.35 kg,平均数±标准差)按保育猪的平均体重分为7个处理,每个处理6栏(每栏为1个重复),每栏饲养24至27头仔猪。7个处理的配方均含30%玉米干酒糟且SID赖氨酸水平均为0.97%,但SID色氨酸与赖氨酸比值分别为14.5%、16.5%、18.0%、19.5%、21.0%、22.5%和24.5%,试验为期21天。试验结果统计采用含异残差的一般线性混合模型。竞争异方差模型包括折线线性(BLL)、折线二次(BLQ)和二次多项式(QP)模型。试验结果根据贝叶斯信息准则来选择最佳模型。在试验1中(体重6~10 kg阶段的保育仔猪),随着SID色氨酸与赖氨酸比值的提高,保育仔猪平均日增重和饲料转化率也提高(呈线性,P0.05)。在仔猪平均日增重方面,最佳模型是二次多项式,获得最佳日增重的SID色氨酸与赖氨酸比值为23.9%(95%置信区间:[14.7%,24.0%])。在仔猪料重比方面,最佳模型是折线线性,获得最佳料重比的SID色氨酸与赖氨酸比值为20.4%(95%置信区间:[14.3%,26.5%])。在试验2中(体重11~20 kg阶段的保育仔猪),随着SID色氨酸与赖氨酸比值的提高,保育仔猪平均日增重和饲料转化率也提高(呈二次方式,P0.05)。在仔猪平均日增重方面,最佳模型是二次多项式,获得最佳日增重的SID色氨酸与赖氨酸比值为21.2%(95%置信区间:[20.5%,21.9%])。在仔猪料重比方面,折线线性和二次折线模型都比较适合,获得最佳料重比的SID色氨酸与赖氨酸比值分别为16.6%(95%置信区间:[16.0%,17.3%])和17.1%(95%置信区间:[16.6%,17.7%])。总结:在试验1中(体重6~10 kg阶段的保育仔猪),获得最佳料重比的SID色氨酸与赖氨酸比值为20.4%,获得最佳日增重的SID色氨酸与赖氨酸比值为23.9%。在试验2中(体重11~20 kg阶段的保育仔猪),获得最佳料重比的SID色氨酸与赖氨酸比值为16.6%,获得最佳日增重的SID色氨酸与赖氨酸比值为21.2%。这些结果表明,NRC(2012)的推荐标准可能低估了体重11~20 kg阶段保育仔猪的SID色氨酸与赖氨酸比值。     

The effects of crossfostering pigs on survival and growth

Data from 254 crossfostered pigs and 753 noncrossfostered pigs of Duroc and Landrace first-parity litters were used to assess the phenotypic effects of crossfostering on baby pigs. Differences between crossfostered and noncrossfostered pigs in the recipient litter were analyzed. Phenotypic correlations were calculated for selected individual pig traits (n = 1007, combined foster and nonfoster data). Birth weight was correlated positively with improved birth vigor (r = .40; P less than .01), survival to 21 d (r = .34; P less than .01) and weight at 21 d (r = .37; P less than .01). Improved birth vigor was correlated positively with pig survival to 21 d (r = .70; P less than .01) and to weaning (r = .66; P less than .01). These correlations indicate that baby pig size and strength are related and that these two characteristics influence survival and performance. Pigs that were not crossfostered (adjusted for birth vigor) had a 4.8% (P less than .10) higher rate of survival to 21 d and a 6.8% (P less than .05) higher rate of survival to weaning (42 d). However, crossfostered pigs had greater birth vigor (P less than .01). Unadjusted for vigor, crossfostered pigs had an 11.3% (P less than .01) higher rate of survival to 21 d and an 8.6% (P less than .05) higher rate of survival to weaning than noncrossfostered pigs. These results indicate that when average-strength pigs were crossfostered, livability was reduced. However, crossfostered pigs that were stronger than average had greater livability than pigs that were not crossfostered.(ABSTRACT TRUNCATED AT 250 WORDS)     

The tryptophan requirement of nursery pigs

Five experiments were conducted to determine the true digestible Trp (dTrp) requirement of nursery pigs. Treatments were replicated with four or five pens of five or six pigs each. Pigs were weaned at 21 (Exp. 1, 2, and 5) or 19 d (Exp. 3 and 4), and fed common diets for various times and then experimental diets for 8 (Exp. 1), 13 (Exp. 2 and 3), or 14 d (Exp. 4 and 5). Experiment 1 (160 pigs, initial and final BW of 8.4 and 11.4 kg) evaluated six protein sources low in Trp relative to a positive control diet to identify the protein source to be used in subsequent experiments. The results indicated that a diet with Canadian field peas (CFP) supplemented with Trp resulted in ADG, ADFI, and gain:feed (GF) equal to (P > 0.10) the positive control diet. In Exp. 2, 75 pigs (initial and final BW of 13.2 and 19.2 kg) were fed 1) Trp-deficient diet (0.13% dTrp) with CFP, 2) Diet 1 with added Trp (0.23% dTrp), or 3) positive control diet (0.22% dTrp). Daily gain, ADFI, and GF were decreased (P < 0.01) in pigs fed Diet 1 compared with pigs fed Diets 2 and 3, but ADG, ADFI, and GF were equal (P > 0.10) in pigs fed Diets 2 and 3. Experiments 3 (180 pigs, initial and final BW of 5.2 and 7.3 kg), 4 (120 pigs, initial and final BW of 6.3 and 10.2 kg), and 5 (144 pigs, initial and final BW of 10.3 and 15.7 kg) were conducted to estimate the dTrp requirement of nursery pigs with diets using CFP as a primary protein source. The diets used in Exp. 3, 4, and 5 contained 1.35, 1.19, or 1.01% dLys, respectively, and other amino acids were provided at 105% the ratio relative to Lys. Response variables were ADG, ADFI, GF, and plasma urea N concentrations, and data were analyzed using the broken-line model. The levels of dTrp in the diets for Exp. 3 (Phase I, 5.2 to 7.3 kg) were 0.14, 0.17, 0.20, 0.23, 0.26, and 0.29%. The average dTrp requirement was estimated to be 0.21% (0.24% total Trp). The levels of dTrp in the diets for Exp. 4 (Phase II, 6.3 to 10.2 kg) were 0.13, 0.16, 0.19, 0.22, 0.25, and 0.28%. The average dTrp requirement was estimated to be 0.20% (0.23% total Trp). The levels of dTrp in the diets for Exp. 5 (Phase III, 10.3 to 15.7 kg) were 0.130, 0.155, 0.180, 0.205, 0.230, and 0.255%. The average dTrp requirement was estimated to be 0.18% (0.22% total Trp). These results indicate that the true dTrp requirement is 0.21, 0.20, and 0.18% for Phase I (5.2 to 7.3 kg), II (6.3 to 10.2 kg), and III (10.3 to 15.7 kg) nursery pigs, respectively.     

Effect of betaine on growth hormone pulsatile secretion and serum metabolites in finishing pigs

An experiment was conducted to investigate the effect of dietary betaine (0%, 0.125%) on growth performance, growth hormone (GH) pulsatile secretion and serum metabolites in crossbred finishing pigs. Three replications of eight pigs (four barrows and four gilts) were used for each treatment, and blood samples for the determination of GH pulsatile secretion were collected every 15 min for 3 h. The results showed that betaine supplementation resulted in 5.45% (p<0.05) increase in average daily gain, whereas average daily feed intake and feed to gain ratio were not affected. Serum basal GH level, mean GH level and GH pulse amplitude were elevated by 41.79% (p<0.01), 48.98% (p<0.01) and 35.05% (p<0.05), respectively, with betaine treatment, but GH pulse frequency and pulse duration remained unchanged (p>0.05). Serum urea nitrogen concentration in pigs fed betaine was 21.58% lower than that of controls (p<0.01), whereas total protein level was significantly increased with betaine supplementation (p<0.05). The study suggests that betaine could promote growth by enhancing GH secretion in finishing pigs.     

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.     

α-酮戊二酸对免疫应激下断奶仔猪肝损伤的影响

24头体质量为(7.25±1.13)kg的(21±1)日龄(杜×长×大)断奶仔猪随机分为3组,每个组设有8个重复,每个重复1头猪。3个组分别为:饲喂基础日粮,注射生理盐水(对照组);饲喂基础日粮,注射脂多糖(LPS)(LPS组);饲喂基础日粮+1%α-酮戊二酸(AKG),注射LPS(AKG组)。预试期7d,正式试验期16d,探讨AKG对免疫应激下断奶仔猪肝损伤的影响。结果显示:(1)LPS刺激导致血清腺苷脱氨酶(ADA)的活性显著升高了15.29%(P0.05),日粮添加1%AKG血清ADA活性较LPS组降低了7.85%(P0.05);(2)LPS刺激导致肝脏丙二醛(MDA)活性显著升高了59.61%(P0.05)以及谷胱甘肽过氧化物酶(GSH-Px)活性显著降低了23.21%(P0.05),而日粮添加1%AKG肝脏MDA活性较LPS组降低了13.70%(P0.05)、GSH-Px活性则升高了17.16%(P0.05);(3)LPS刺激导致肝脏总蛋白质含量和RNA/DNA比值分别显著增加了8.20%(P0.05),10%(P0.05),而日粮添加1%AKG较LPS组肝脏总蛋白质含量和RNA/DNA比值分别降低了3.94%(P0.05),10%(P0.05)。结果表明:AKG能在一定程度上缓解LPS刺激对断奶仔猪肝脏的损伤。