Dietary phosphorus and an inflammatory challenge affect performance and immune function of weanling pigs

Ninety-six 3-wk-old pigs (6.3+/-0.12 kg initial BW) were allotted to one of eight treatments based on BW and litter origin to determine the effect of dietary phosphorus and an inflammatory challenge on performance and immune function. Four corn-soybean meal-based treatment diets were formulated to contain 0.16, 0.24, 0.32, or 0.40% available P. Monocalcium-dicalcium phosphate was used as the supplemental P source. The Ca:available P ratio was maintained at 2:1. To challenge the pigs, half of the pigs in each dietary treatment were injected i.m. with E. coli lipopolysaccharide (200 microg/kg of BW) on d 7 and 14. This resulted in a 2 x 4 factorial arrangement of treatments. Average daily gain for the 35-d study was increased linearly (P < 0.01) by increasing supplemental P. Average daily gain and ADFI were decreased (P < 0.05) by lipopolysaccharide injection. Serum P concentrations increased linearly (P < 0.01) with increasing supplemental P. Antibody titers to the injection of sheep red blood cells and ovalbumin on d 21 decreased linearly (P < 0.10) by increasing supplemental P. In vitro blastogenic response of lymphocytes to phytohemagglutinin (PHA) on d 25 was increased linearly (P < 0.05) by increasing supplemental P. Blastogenic response of lymphocytes to pokeweed mitogen on d 25 was not affected. On d 31, skinfold thickness 6 h following an intradermal injection of PHA was increased quadratically (P < 0.07) by increasing supplemental P. There were no P x lipopolysaccharide interactions for any immune response measure. In conclusion, increasing supplemental P increased ADG and enhanced cell-mediated immune response but decreased humoral immune response.     

Effect of mannan oligosaccharides on growth performance of weanling pigs

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

Effects of increasing dietary L-carnitine on growth performance of weanling pigs

Four experiments were conducted to evaluate the effects of supplementing graded levels (0 to 100 ppm) of L-carnitine to the diet of weanling pigs on growth performance during a 34- to 38-d experimental period. A fifth experiment was conducted to determine the effects of addition of L-carnitine to diets with or without added soybean oil (SBO) on growth performance. In Exp. 1, 128 pigs (initial BW = 5.5 kg) were allotted to four dietary treatments (six pens per treatment of four to six pigs per pen). Dietary treatments were a control diet containing no added L-carnitine and the control diet with 25, 50, or 100 ppm of added L-carnitine. In Exp. 2, 3, and 4, pigs (4.8 to 5.6 kg of BW) were allotted to five dietary treatments consisting of either a control diet containing no added L-carnitine or the control diet with 25, 50, 75, or 100 ppm of added L-carnitine. All diets in Exp. 1 to 4 contained added soybean oil (4 to 6%). There were seven pens per treatment (four to five pigs per pen) in Exp. 2, whereas Exp. 3 and 4 had five and six pens/treatment (eight pigs per pen), respectively. In general, dietary carnitine additions had only minor effects on growth performance during Phases 1 and 3; however, dietary L-carnitine increased (linear [Exp. 1], quadratic [Exp. 2 to 4], P < 0.03) ADG and gain:feed (G:F) during Phase 2. The improvements in growth performance during Phase 2 were of great enough magnitude that carnitine addition tended to increase ADG (linear, P < 0.10) and improve G:F (quadratic, P < 0.02) for the entire 38-d period. In Exp. 5, 216 weanling pigs (5.8 kg of BW) were allotted (12 pens/treatment of four to five pigs per pen) to four dietary treatments. The four dietary treatments were arranged in a 2 x 2 factorial with main effects of added SBO (0 or 5%) and added L-carnitine (0 or 50 ppm). Pigs fed SBO tended (P < 0.07) to grow more slowly and consumed less feed compared with those not fed SBO, but G:F was improved (P < 0.02). The addition of L-carnitine did not affect (P > 0.10) ADG or ADFI; however, it improved (P < 0.03) G:F. Also, the increase in G:F associated with L-carnitine tended to be more pronounced for pigs fed SBO than those not fed SBO (carnitine x SBO, P < 0.10). These results suggest that the addition of 50 to 100 ppm of added L-carnitine to the diet improved growth performance of weanling pigs. In addition, supplemental L-carnitine tended to be more effective when SBO was provided in the diet.     

Sulfur concentration in diets containing corn, soybean meal, and distillers dried grains with solubles does not affect feed preference or growth performance of weanling or growing-finishing pigs

Four experiments were conducted to investigate the effects of distillers dried grains with solubles (DDGS) and dietary S on feed preference and performance of pigs. In a 10-d feed preference experiment (Exp. 1), 48 barrows (20.1 ± 2.2 kg of BW) were randomly allotted to 3 treatment groups, with 8 replicate pens per treatment and 2 pigs per pen. A control diet based on corn and soybean meal, a DDGS diet containing 20% DDGS, and a DDGS-sulfur (DDGS-S) diet were prepared. The DDGS-S diet was similar to the DDGS diet with the exception that 0.74% CaSO(4) was added to the diet. Two diets were provided in separate feeders in each pen: 1) the control diet and the DDGS diet, 2) the control diet and the DDGS-S diet, or 3) the DDGS diet and the DDGS-S diet. Preference for the DDGS diet and the DDGS-S diet vs. the control diet was 35.2 and 32.6%, respectively (P < 0.05), but there was no difference between the DDGS diet and the DDGS-S diet. In Exp. 2, a total of 90 barrows (10.3 ± 1.4 kg of BW) were allotted to 3 treatments, with 10 replicate pens and 3 pigs per pen, and were fed the diets used in Exp. 1 for 28 d, but only 1 diet was provided per pen. Pigs fed the control diet gained more BW (497 vs. 423 and 416 g/d; P < 0.05) and had greater G:F (0.540 vs. 0.471 and 0.455; P < 0.05) than pigs fed the DDGS or the DDGS-S diet, but no differences between the DDGS and the DDGS-S diets were observed. In a 10-d feed preference experiment (Exp. 3), 30 barrows (49.6 ± 2.3 kg of BW) were allotted to 3 treatment groups, with 10 replicates per group. The experimental procedures were the same as in Exp. 1, except that 30% DDGS was included in the DDGS and DDGS-S diets and 1.10% CaSO(4) was added to the DDGS-S diet. Feed preference for the DDGS and the DDGS-S diets, compared with the control diet, was 29.8 and 32.9%, respectively (P < 0.01), but there was no difference between the DDGS and the DDGS-S diets. In Exp. 4, a total of 120 barrows (34.2 ± 2.3 kg of BW) were fed grower diets for 42 d and finisher diets for 42 d. Diets were formulated as in Exp. 3. Pigs on the control diets gained more BW (1,021 vs. 912 and 907 g/d; P < 0.05) and had greater G:F (0.335 vs. 0.316 and 0.307; P < 0.05) than pigs fed the DDGS or DDGS-S diet, respectively, but no differences between pigs fed the DDGS and the DDGS-S diets were observed. In conclusion, dietary S concentration does not negatively affect feed preference, feed intake, or growth performance of weanling or growing-finishing pigs fed diets based on corn, soybean meal, and DDGS.     

纳米氧化锌对断奶仔猪生长性能的影响

选用63头断奶仔猪,分为处理1组(3000mg/kg普通饲料级氧化锌)、处理2组(250mg/kg纳米氧化锌)、处理3组(500mg/kg纳米氧化锌)三个处理,每个处理3个重复,每个重复7头仔猪,试验期20d。结果表明:纳米氧化锌(500mg/kg)能显著提高断奶仔猪的日增重(与处理1组相比,提高9.91%),改善肉料比,有较好的经济效益。     

功能性低聚糖对断奶仔猪腹泻的防治及生产性能的影响

在仔猪饲粮中分别添加低聚果糖(FOS)、异麦芽低聚糖(GOS)和甘露寡糖(MOS),用48头35日龄杜×长断奶仔猪进行了为期28 d的饲养试验,观察了功能性低聚糖对断奶仔猪腹泻的防治作用及生产性能的影响.将试验猪随机分为4组,即在基础日粮中分别添加FOS 3 g/kg、GOS 2 g/kg和MOS 3 g/kg的3个处理组和1个对照组,观察了仔猪的生长发育情况,记录了各组耗料量和体重,采集血清和全血以及粪样进行了分析测试.结果表明,FOS组仔猪腹泻频率降低了66%;GOS组降低了25%;MOS组降低了54%;FOS、GOS和MOS组的血清SOD、GSH-Px活性均较对照组显著提高(P＜0.05或P＜0.01);3种低聚糖组仔猪的外周血T淋巴细胞数(CD3)、IgG水平均较对照组显著提高(P＜0.05或P＜0.01);3种低聚糖组仔猪的日增重和饲料报酬均有明显的提高.     

Effects of stachyose on performance, diarrhoea incidence and intestinal bacteria in weanling pigs.

A three-week trial was conducted to evaluate the effects of the oligosaccharide stachyose on performance, diarrhoea incidence and intestinal bacterial populations in weaned pigs (7.96 +/- 0.2kg). A total of 144 crossbred (Landrace x Large White x Duroc) pigs weaned at 28 days were allotted to one of four treatments with six pens per treatment and six pigs per pen. The experimental diets were based on maize, dried whey and whole-fat milk and were supplemented with 0, 1 or 2% stachyose. A fourth diet contained no milk but instead contained 20% soybean meal to provide 0.78% stachyose and 0.21% raffinose. Inclusion of 1 or 2% stachyose in the diet depressed growth compared with pigs fed the control diet. Pigs fed the soybean meal diet gained weight at a rate similar to pigs fed the diet containing 1% added stachyose. Diarrhoea incidence was highest for pigs fed the soybean meal diet and lowest for pigs fed the control diet, with pigs fed the diets containing stachyose being intermediate. Pigs fed 1% stachyose had more lactobacilli in the ileum as well as more bifidobacteria in the caecum and colon than control pigs. They also had fewer enterobacteria in the colon. In contrast, pigs fed the diet containing 2% stachyose had fewer lactobacilli and bifidobacteria in the jejunum, ileum and caecum than did control pigs. Volatile fatty acids in the ileum, caecum and colon were highest for pigs fed 1% stachyose and lowest for pigs fed 2% stachyose. Volatile fatty acid concentrations were not significantly different between pigs fed the soybean meal diet and those fed the control. The overall results of this experiment indicate that the oligosaccharide stachyose had a negative effect on pig performance and its presence may partially explain the poorer performance observed when soybean meal is used as the sole source of supplemental protein in cereal-based diets fed to weaned pigs.     

发酵乳清粉对断奶仔猪生产性能、腹泻率和消化能力的影响

<正>乳清粉是乳品工业的副产物,含有丰富的营养物质,可向动物尤其是幼龄动物提供丰富的营养素。同时,乳清粉又是一种很容易消化吸收的物质,非常适合刚断奶这一特殊生理阶段的仔猪。目前,在断奶仔猪饲料中乳清粉已被普遍使用。     

日粮系酸力对断奶仔猪生长性能的影响

日粮的系酸力又称为日粮酸缓冲力、酸中和力、酸结合力或酸结合系数，即日粮结合酸的能力。Bolduan(1988)把它定义为使100 g饲料日粮的pH值降至4.0时所需盐酸的毫摩尔数，也有人把它定义为使1 kg饲料pH值降至3.0时所需盐酸的毫克当量。猪胃内蛋白酶原激活需要游离H ，胃蛋白酶活性有两个最优pH值2.0和3.5(kidder和Manners,1978)，健康仔猪胃内pH值一般低于4.0。当仔猪摄食系酸力高的日粮后，进入胃内的饲料要结合一定量的胃酸，使胃内pH值升高，进而影响胃内有关酶的活性，降低养分特别是蛋白质在胃内的消化率，甚至影响小肠的营养物质…     

不同系酸力饲粮对断奶仔猪生产性能和腹泻的影响

试验研究了复合酸化剂与饲料系酸力的关系以及饲料系酸力对断奶仔猪生产性能和腹泻率的影响。试验结果表明:随着复合酸化剂的添加,饲料系酸力不断降低;仔猪的腹泻率随系酸力的降低相应降低,日增重和料重比均有不同程度的改善;系酸力过低(小于20)时仔猪的采食量急剧上升而生产性能下降;饲料系酸力为19.5～23时,仔猪的综合生产性能表现最佳。     

植物提取物对断奶仔猪生产性能和经济效益的影响

为考察植物提取物的应用效果,选择100头28日龄平均体重7.34＋0．11kg的长×大断奶仔猪,按性别、体重、品种一致的原则随机分成4个处理,每个处理5个重复,每个重复5头仔猪。分别饲喂添加15mg／kg阿维拉霉素＋250mg／kg氧化锌、40mg／kg吉它霉素＋7．5mg／kg黄霉素、400mg／kg诺必达、300mg／kg植物提取物。结果表明：在试验全期中．4个处理组在平均日采食量和平均日增重上无显著性差异（P〉0．05）;在料肉比方面,黄霉素＋吉它霉素组显著高于其他各组（P〈0．05）,其他各组之间差异不显著（P〉0.05）;腹泻次数以阿维拉霉素＋氧化锌组和植物提取物组最少（P〈0．05）,其他各组差异不明显（P〉0.05）。在经济效益方面。阿维拉霉素＋氧化锌组最好,其次为植物提取物组。     

Growth performance,nutrient digestibility,and fecal microflora in weanling pigs fed live yeast

Two experiments were conducted to evaluate the effects of live yeast supplementation on nursery pig performance, nutrient digestibility, and fecal microflora and to determine whether live yeast could replace antibiotics and growth-promoting concentrations of Zn and Cu in nursery pigs. In Exp. 1, 156 pigs were weaned at 17 d of age (BW = 5.9 kg) and allotted to a 2 x 2 factorial randomized complete block design (six or seven pigs per pen with six pens per treatment). Factors consisted of 1) dietary supplementation with oat products (oat flour and steam-rolled oats; 0 or 27.7%) and 2) yeast supplementation at 0 or 1.6 x 10(7) cfu of Saccharomyces cerevisiae SC47/g of feed. In Exp. 2, 96 pigs were weaned at 17 d of age and allotted to a 2 x 2 factorial randomized complete block design (four pigs per pen with six pens per treatment) with factors of 1) diet type (positive control containing growth-promoting concentrations of Zn, Cu, and antibiotics or negative control) and 2) live yeast supplementation (0 or 2.4 x 10(7) cfu of Saccharomyces cerevisiae SC47/g of feed). The inclusion of oat products in Exp. 1 decreased (P < 0.10) overall ADG and final BW. Yeast supplementation did not affect growth performance of pigs in Exp. 1 (P = 0.65); however, ADG in Exp. 2 was 10.6% greater (P < 0.01) and ADFI was increased by 9.4% (P < 0.10) in pigs supplemented with yeast in the positive control diet. Addition of Zn, Cu, and antibiotics to the diet improved gain:feed ratio during the prestarter period (P < 0.02) and overall (P = 0.10). In Exp. 1, inclusion of oat products increased (P < 0.01) total bacteria in feces when measured on d 10. Fecal lactobacilli measured on d 28 were reduced (P < 0.05) in pigs fed diets with oat products and yeast (interaction, P < 0.05). In Exp. 2, yeast supplementation decreased (P < 0.05) total bacteria and lactobacilli. Dietary yeast resulted in a greater (P < 0.05) yeast count in feces of pigs during the starter phase of Exp. 1. Yeast decreased (P < 0.10) the digestibility of DM, fat, and GE in the prestarter phase and DM, fat, P, and GE in the starter phase, whereas oat products increased the digestibility of DM, CP, fat, and GE (P < 0.05) in the prestarter phase. Results indicate that live yeast supplementation had a positive effect on nursery pig performance when diets contained growth-promoting antimicrobials. Nonetheless, the response was variable, and the conditions under which a response might be expected need to be further defined.     

酵母蛋白饲料和鱼粉对断奶仔猪生产性能影响的比较研究

试验采用单因子设计,在保证营养水平相同的情况下,共设5种日粮,其中包括对照组(基础日粮)、鱼粉组(基础日粮+2.5%鱼粉)、酵母组(基础日粮+2.5%酵母)、酵母去酶组(基础日粮+2.5%酵母并扣除酶制剂)和酵母去药组(基础日粮+2.5%酵母并扣除抗生素)。选用28日龄断奶的DLY三元杂交仔猪60头,试验期为28d。试验主要考察平均日采食量(ADFI)、平均日增重(ADG)和料肉比(F/G)。结果表明,从整个试验期来看,添加酵母组和鱼粉组都能提高仔猪的生产性能,尤以酵母组的提高幅度最大,酵母组的ADG、ADFI分别较对照组提高14.9%(P<0.05)、4.2%,料肉比降低了9.5%(P<0.05);ADG、ADFI分别较鱼粉组提高10.6%、5.4%,料肉比降低4.7%(P<0.05)。通过比较对照组、鱼粉组、酵母去酶组、酵母去药组这4组全期生产性能指标,发现对照组虽然采食量较高,但ADG和料肉比仍是最差,其中料肉比明显高于酵母去酶组和鱼粉组(P<0.05);酵母去酶组较对照组ADG提高6.4%,料肉比降低11.9%(P<0.05);酵母去药组较对照组ADG提高1.7%,料肉比降低2.0%,差异不显著(P>0.05)。试验结果说明,酵母代替鱼粉的效果是肯定的,同时具有替代酶制剂的潜力,另外,酵母饲料作为一种绿色的饲料来源,在一定条件下代替抗生素也是可行的。     

Effect of salmon protein hydrolysate and spray-dried plasma protein on growth performance of weanling pigs

Two experiments, each consisting of 2 trials, were conducted to determine the effect of salmon protein hydrolysate (SPH) and spray-dried plasma protein (SDPP) fed during the first week postweaning and their subsequent effect on the growth performance of weanling pigs. Pigs were fed in a 3-phase feeding program with durations of 7 d for phase 1 in both Exp. 1 and 2; 14 or 15 d for phase 2 in Exp. 1 and 2, respectively; and 7 or 8 d for phase 3 in Exp. 1 and 2, respectively. Dietary treatments were fed only during phase 1, whereas the same diet was fed to all pigs in phases 2 and 3. Pigs were blocked by initial BW and sex, and littermates were balanced across treatments. Data from the 2 trials within each experiment were combined and analyzed together; no treatment × trial interactions (P > 0.10) were observed. In Exp. 1, a total of 324 weanling pigs (10 replications of 5 or 6 pigs per pen) with an average initial BW of 6.4 ± 1.3 kg were assigned to 1) a control diet with no SPH or SDPP, 2) 1.5% SPH, 3) 3.0% SPH, 4) 1.5% SDPP, 5) 3.0% SDPP, or 6) 1.5% SPH + 1.5% SDPP. Experiment 2 was similar to Exp. 1, but red blood cells were removed from all diets to reduce diet complexity. In Exp. 2, weanling pigs (n = 320, 14 replications of 5 or 6 pigs per pen) with an average initial BW of 5.4 ± 1.2 kg were assigned to 1) a control diet with no SPH or SDPP, 2) 1.5% SPH, 3) 1.5% SDPP, or 4) 1.5% SPH + 1.5% SDPP. Three batches of SPH were used, and each batch was analyzed for AA composition. In Exp. 1, the inclusion of SDPP or SPH during phase 1 did not affect (P > 0.10) ADG, ADFI, or G:F compared with those of pigs fed the control diet. No carryover effects on growth performance were observed in any of the subsequent phases. Overall, G:F was greater (P = 0.08) in pigs fed the 1.5% diets compared with those fed the 3.0% diets. In Exp. 2, no differences (P > 0.10) were observed in ADG, ADFI, or G:F among pigs fed the SPH or SDPP diets compared with those of pigs fed the control diet. Pigs fed the combined diet had greater (P < 0.10) overall ADFI compared with that of pigs fed the control diet, but ADFI was similar to that of pigs fed the SPH and SDPP diets. These results indicate that inclusion of up to 3% SDPP or SPH in diets fed during the first week postweaning did not affect the growth performance of weanling pigs, and no subsequent carryover effects were observed. Salmon protein hydrolysate did not affect the growth performance of weanling pigs and may be considered an alternative protein source in diets for weanling pigs.     

环磷酰胺对断奶仔猪免疫功能的影响

本试验旨在探讨环磷酰胺(CY)对断奶仔猪免疫功能的影响。选取12头(28±3)d的杜×长×大断奶仔猪,随机分为对照组和CY组。第1天和第7天,给CY组仔猪注射50mg/kg BW的CY,对照组仔猪注射等量的生理盐水;第7天和第14天,前腔静脉采血待测;第14天,测定迟发型超敏反应。结果表明:(1)CY可降低第7天断奶仔猪的中性粒细胞数量(P0.1)及第14天白细胞、淋巴细胞、中性粒细胞(P0.05)和单核细胞数量(P0.1);(2)CY可降低第14天牛血清白蛋白抗体水平(P0.05);(3)CY可降低第7天干扰素-γ水平(P0.05)。本研究结果表明,CY可抑制断奶仔猪的免疫功能。     

高剂量甘氨酸铜对断奶仔猪生产性能和血液指标的影响

微量元素铜对动植物营养有重要作用，如日粮中添加高剂量铜可使猪的生产性能得到提高。猪对铜的吸收部位主要在小肠前段，胃只吸收其中的一小部分。断奶仔猪对铜的表观吸收率在5 %～20 %之间(Roof等，1982)，成年动物的吸收率一般不高于5 %～10 %(倪可德等，1995)。大量未被吸收的铜和内源损耗铜随粪、尿排出体外。鉴于铜对猪的促生长作用优于使用抗生素，尽管作用机理尚未明确，但使用高剂量铜却相当普遍。大量的粪铜排出污染环境，为此许多学者开始重视对不同化学形态的铜源使用效价进行评定，以确定既有利于促进猪只生长，又可降低铜源…     

早期断奶仔猪蛋白质营养研究进展

早期断奶最大障碍在于仔猪的消化机能不健全而对饲料的要求特别高。本文结合早期断奶仔猪消化生理特点,介绍了仔猪断奶后氨基酸营养的需要和各种蛋白质饲料原料的营养价值,为调制由母乳过渡到仔猪日粮且不影响仔猪生长率的蛋白质饲粮提供参考。     

Effects of supplementation of beta-glucans on growth performance, nutrient digestibility, and immunity in weanling pigs

Two experiments were conducted to evaluate the efficacy of beta-glucan on growth performance, nutrient digestibility, and immunity in weanling pigs. In Exp. 1, 210 weanling pigs (6.38 +/- 0.92 kg of BW) were fed dietary beta-glucan (0, 0.01, 0.02, 0.03, or 0.04%) for 5 wk. In Exp. 2, 168 pigs (6.18 +/- 1.31 kg of BW) were fed no beta-glucan or antibiotics (T1), 0.02% beta-glucan (T2), only antibiotics (T3), or 0.02% beta-glucan with antibiotics (T4) for 8 wk. In Exp. 2, the antibiotics fed were apramycin and carbadox in phase I (0 to 2 wk) and carbadox and chlortetracycline in phase II (3 to 8 wk). During Exp. 2, the performance study was conducted for 5 wk, and the immune response was tested until 8 wk. In Exp. 1, there was a trend for a linear increase (P = 0.068) in ADG as the dietary beta-glucan concentration increased in the diet. The digestibilities of DM, GE, CP, ether extract, Ca, and P increased linearly (P < 0.05) in the beta-glucan-supplemented pigs. In Exp. 2, the overall ADG was greater (P < 0.05) in treatment T4 compared with the control group (T1). Also, except for P, this group showed greater (P < 0.05) nutrient digestibilities than the control group. In Exp. 2, at d 15, 24, and 46 antibody titers were measured by ELISA against Pasteurella multocida type A and D after vaccination with atrophic rhinitis, and they differed significantly (P < 0.05) with no particular trend. Flow cytometry was used to determine porcine lymphocyte subpopulations at 4 and 8 wk of Exp. 2. There was an increase in CD4 cells (P < 0.05) and a trend for an increase in CD8 cells (P < 0.10) at 8 wk in pigs fed the T2 diet compared with the other groups. Overall, increasing the dietary concentrations of beta-glucan did not improve ADG without antibiotic, and in weanling pigs antibiotics seem to be more effective in improving nutrient digestibilities and growth performance than beta-glucan.     

Effect of creep feed consumption on individual feed intake characteristics and performance of group-housed weanling pigs

To assess the effects of creep feed consumption on individual feed intake characteristics and performance of group-housed weaned pigs, 16 litters (149 piglets) were fed a commercial creep feed (3,040 kcal NE/kg, 15.2 g lysine/kg) supplemented with 1% chromic oxide. Another five litters (48 piglets) were not given access to creep feed (no-feed). Piglets were weaned at 28 d after birth. On d 18, 22, and 27 of age, fecal samples from all the piglets were taken using fecal loops. A green color of the feces indicated that the piglet had eaten creep feed. Piglets that had green-colored feces three times were considered as eaters. Piglets that never showed green-colored feces were considered as non-eaters. At weaning 22 piglets of each type (no-feed, non-eaters, and eaters) were selected based on BW, litter origin, and sex. These 66 pigs were assigned to six pens equipped with computerized feeding stations. Eaters, non-eaters, and no-feed pigs were equally divided over all six pens. After weaning a prestarter (d 0 to 13) and a starter diet (d 14 to 34) were offered for ad libitum consumption. The individual feed intake characteristics of latency time (interval between weaning and first feed intake) and initial feed intake (intake during the first 24 h following first feed intake) and performance traits were determined for all piglets. The pigs that were designated as eaters needed less time between weaning and first feed intake than the pigs that were designated as non-eaters and no-feed pigs (P = 0.04 and P = 0.06, respectively). Initial feed intake was not affected (P > 0.1) by feed intake prior to weaning. However, during d 0 to 8 the eaters had more visits per day during which feed was consumed than both the non-eaters and no-feed pigs. Averaged over the first 8 d after weaning, the ADFI and ADG of the eaters were higher than that of the non-eaters and no-feed pigs (P < 0.05). Averaged over the total 34-d period the effect of creep feed intake on postweaning ADFI was much less pronounced (P = 0.20), whereas ADG of the eaters was the highest (P < 0.05). Creep feed intake during the sucking period stimulates early postweaning feed intake as well as postweaning performance.