德州驴盲结肠食糜液中纤维降解酶活性与挥发性脂肪酸含量的比较分析

本试验旨在比较分析德州驴盲结肠食糜液中纤维降解酶活性以及挥发性脂肪酸(VFA)的含量。采集9头德州驴的盲肠、腹结肠和背结肠食糜液样品,经4层纱布过滤后,通过分光光度计法测定羧甲基纤维素酶(CMCase)、微晶纤维素酶(AVI)、木聚糖纤维素酶(Xlyse)、阿魏酸酯酶(FAE)和乙酰酯酶(AE)活性,此外,使用气相色谱法测定VFA含量,每个指标3个平行。结果表明：CMCase、AVI与Xlyse活性在驴盲肠、腹结肠和背结肠食糜液中依次增加(P<0.05),而FAE活性在驴盲结肠间无显著差异(P>0.05)。驴背结肠食糜液中AE活性显著高于盲肠与腹结肠(P<0.05)。乙酸摩尔比例在驴盲肠、腹结肠和背结肠食糜液中依次显著增加(P<0.05),丙酸摩尔比例依次降低(P<0.05)。而且驴结肠食糜液中支链VFA含量显著高于盲肠(P<0.05)。综上所述,本研究明确了驴盲结肠食糜液具有较高的催化水解饲料细胞壁半纤维素与木质素分子间酯键连接的FAE和AE活性,随着驴后肠段逐渐后移,驴盲肠、腹结肠与背结肠食糜液中乙酸摩尔比例依次增加,丙酸摩尔比例依次降低。     

梅山与长白母猪粪样微生物体外发酵八种纤维底物的特性比较

本研究旨在比较不同品种母猪(梅山猪与长白猪)粪样中微生物对不同纤维底物的体外降解能力,同时分析粪样中的主要纤维降解菌数量。采集梅山(n=5)和长白(n=5)母猪新鲜粪样作为发酵接种物,以果胶、纤维素、菊粉、麦壳、麸皮、木聚糖、玉米芯渣及苜蓿作为纤维底物进行体外发酵,测定产气量和发酵液挥发性脂肪酸(volatile fatty acid,VFA)浓度。粪样同时用于提取细菌总核酸,变性梯度凝胶电泳(denaturing gradient gel electrophoresis,DGGE)和real-time PCR对菌群区系进行分析。体外发酵结果表明,从发酵后9 h至96 h结束,长白猪接种物各组的累积产气量、有机物校正产气量分别显著(P<0.05)和极显著(P<0.01)高于梅山猪,长白猪T_1/2和T_max显著低于梅山猪(P<0.05),且发酵终产物中乙酸和总VFA浓度显著高于梅山猪接种物(P<0.05),整个发酵过程中不同底物间累积产气量差异显著(P<0.05),累积产气量从高到低的组别依次为:菊粉>麸皮>果胶>苜蓿>麦壳>玉米芯渣>木聚糖>纤维素。DGGE分析表明,梅山与长白母猪粪样菌群图谱中存在许多共同条带。Real-time PCR定量分析表明,梅山母猪粪样中的总细菌的16S rRNA基因拷贝数显著高于长白母猪(P<0.05),而拟杆菌、产琥珀酸丝状杆菌、黄化瘤胃球菌和白化瘤胃球菌等纤维降解菌数量及其占总菌比例差异均不显著(P>0.05)。结果显示,尽管2个品种母猪粪样中纤维降解菌数量无显著差异,但是长白母猪粪样微生物体外发酵纤维底物的能力高于梅山母猪。     

Diversity and community pattern of sulfate-reducing bacteria in piglet gut

Background: Among the gut microbiota, sulfate-reducing bacteria(SRB) is a kind of hydrogen-utilizing functional bacteria that plays an important role in intestinal hydrogen and sulfur metabolism. However, information is lacking regarding diversity and community structure of SRB in the gut of piglets. Middle cecum contents were collected from 6 Yorkshire and 6 Meishan piglets at postnatal days(PND) 14, 28 and 49. Piglets were weaned at PND28. Real-time quantitative PCR was performed to detect the number of SRB in the cecum based on dissimilatory sulfite reductase subunit A(dsrA) gene. Prior to real-time PCR, plasmid containing the dsrA gene was constructed and used as external standard to create a standard curve, from which the gene copies of dsrA were calculated. H_2S concentration in the cecal contents was measured. Illumina PE250 sequencing of dsrA gene was used to investigate SRB diversity in cecum contents.Results: The qPCR results showed that the number of SRB at PND49 was significantly higher than that at PND28 in Meishan piglets. The concentration of H_2S has no significant difference between piglet breeds and between different ages. The Illumina sequencing analysis revealed that the Chao1 richness index was significantly higher at PND49 than that at PND14 and PND28 in Yorkshire piglets. Based on dsrA gene similarities, Proteobacteria, Actinobacteria, and Firmicutes were identified at the phylum level, and most sequences were classified as Proteobacteria. At the genus level, most of sequences were classified as Desulfovibrio. At the species level, Desulfovibrio intestinalis was the predominant SRB in the piglet cecum. The relative abundance and the inferred absolute abundance of Faecalibacterium prausnitzii at PND49 were significantly higher than that at PND14 in Yorkshire piglets. Pig breeds did not affect the dsrA gene copies of SRB, diversity index and community pattern of SRB.Conclusions: Sulfate-reducing bacteria are widely colonized in the cecum of piglets and D. intestinalis is the dominant SRB. The age of piglets, but not the pig breeds affects the diversity and community pattern of SRB.     

妊娠后期母猪和仔猪补饲外源精胺对初生和28日龄仔猪肠道形态结构及二糖酶活性的影响

本文通过研究妊娠后期母猪和仔猪补饲外源精胺对初生和28日龄仔猪肠道形态结构和二糖酶活性的影响,初步探讨干预“仔猪早期断奶综合征”的技术措施.试验第1阶段,选择6头体重和膘情相近、胎次为3、已怀孕91 d的健康“长×大”母猪,随机分为Ⅰ、Ⅱ和Ⅲ3个组,每个组设2个重复,每个重复1头母猪.Ⅰ、Ⅱ和Ⅲ组妊娠母猪饲粮中外源精胺的添加量为0、1.5和3.0 mg/kg,饲喂至分娩结束;第2阶段,分娩后母猪采食同一种不含外源精胺的饲粮,Ⅰ、Ⅱ和Ⅲ组哺乳仔猪于7日龄起相应补饲外源精胺添加量为0、3.0和6.0 mg/kg的哺乳仔猪饲粮至28日龄.在仔猪初生和28日龄时,分别从每窝仔猪中选1头接近平均体重的健康仔猪进行屠宰,用于胃肠发育指标的测定.结果表明:与未添加外源精胺相比,妊娠母猪饲粮添加3.0 mg/kg外源精胺显著提高了初生仔猪十二指肠和回肠的柱状细胞数量、十二指肠和空肠的杯状细胞数量(P＜0.05),显著增加了空肠隐窝深度(P＜0.05),显著提高了麦芽糖酶和蔗糖酶比活力(P＜0.05);哺乳仔猪饲粮添加6.0 mg/kg外源精胺显著增加了28日龄仔猪空肠黏膜重(P＜0.05),显著提高了十二指肠和空肠的麦芽糖酶和蔗糖酶比活力(P＜0.05),极显著增加了空肠柱状细胞和杯状细胞数量(P＜0.01),极显著增加了十二指肠和空肠隐窝深度(P＜0.01).因此,在妊娠后期母猪和哺乳仔猪饲粮中添加外源精胺有利于初生和28日龄仔猪肠道形态结构的改善和二糖酶活性的提高.     

益生菌制剂对早期断奶仔猪肠道pH、黏膜形态结构和挥发性脂肪酸含量的影响

本试验旨在研究益生菌制剂对早期断奶仔猪肠道pH、黏膜形态结构和挥发性脂肪酸含量的影响.选用48头平均体重为(6.39±0.42)kg的(21±2)日龄“杜×长×大”三元杂交断奶仔猪,按性别、体重和窝源基本一致原则随机分为2个组,每个组4个重复,每个重复6头猪.试验1组为对照组,采用基础饲粮;试验2组为益生菌组,每千克基础饲粮中添加1×109 CFU活菌.试验期为21d.结果表明:1)28日龄时,益生菌组回肠内容物pH显著低于对照组(P＜0.05).2)和对照组相比,添加益生菌制剂,28日龄时,显著增加空肠、回肠绒毛高度和上皮内淋巴细胞数量(P＜0.05),显著提高回肠杯状细胞数量(P＜0.05),显著降低回肠隐窝深度(P＜0.05);35日龄时,显著增加空肠、回肠绒毛高度(P＜0.05),显著提高空肠上皮内淋巴细胞数量(P＜0.05),显著降低空肠、回肠隐窝深度(P＜0.05);42日龄时,显著增加空肠、回肠绒毛高度,显著提高空肠上皮内淋巴细胞和杯状细胞数量(P＜0.05),显著降低空肠隐窝深度(P＜0.05).3)28日龄时,益生菌组盲肠内容物中丁酸和乳酸含量显著高于对照组(P＜0.05);35日龄和42日龄时,益生菌组盲肠内容物中乙酸、丙酸、丁酸和乳酸含量显著高于对照组(P＜0.05).由结果可知,添加益生菌制剂能改善断奶应激对绒毛高度和隐窝深度的影响,提高肠道淋巴细胞数量和挥发性脂肪酸含量,降低肠道pH,从而缓解断奶应激对肠道环境的影响.     

Comparison effects of dietary iron dextran and bacterial‐iron supplementation on growth performance,fecal microbial flora,and blood profiles in sows and their litters

This study was conducted to compare effects of dietary administration of iron dextran and bacterial‐iron on growth performance, fecal microbial flora, and blood profiles in sows and their litters. A total of 20 multiparous sows (Landrace × Yorkshire) were randomly allotted into two treatments: (i) ID (basal diet, piglets were injected with iron dextran); (ii) BR (basal diet + bacterial‐iron; bacterial‐iron was given to sows, piglets were not injected with iron dextran). There were five replicates per treatment with two sows per replicate. No differences were observed on sow and piglet growth performance, fecal microbial flora as well as sow blood profiles between ID and BR treatments. In piglets, blood iron, red blood cell and hemoglobin concentrations in ID treatment were higher (P < 0.05) on days 12 and 24. Furthermore, concentration of white blood cells in BR treatment was lower (P < 0.05) on day 12. However, the percentage of lymphocytes on day 12 was increased (P < 0.05) in BR treatment. In conclusion, effect of iron dextran and bacterial‐iron has no difference on growth performance in lactating sows and piglets, but iron dextran injection has higher blood iron, white blood cell, red blood cell and hemoglobin concentrations in piglets.     

Pig colostrum and milk composition:comparisons between Chinese Meishan and US breeds

The composition of colostrum and milk from Chinese Meishan and American Yorkshire gills was characterized at farrowing (d 0), 24 h after farrowing (d 1), and on d 7 and 21 of lactation. Lactose concentrations were lower for Meishan vs. Yorkshire gills on d 0, 1, and 7, but not on d 21. Fat concentrations were higher for Meishan than for Yorkshire gilts at each sampling time, particularly on d 1 and 7. Total protein concentrations were similar on d 0 and 1, but lower for Meishan than for Yorkshire gilts on d 7 and 21. Milk proteins from Meishan gilts, Yorkshire gilts, and crossbred sows (Yorkshire × Hampshire × Landrace) were compared by polyacrylamide gel electrophoresis. Differences in size or relative proportion of caseins and the major whey proteins were not observed. Several high molecular weight whey proteins and a minor casein band were observed to segregate among breeds. These protein differences among breeds may be valuable markers in studies on lactating Mei-shan × Yorkshire crossbred animals. Results of this study suggest that colostrum and milk composition should not be a major limiting factor in survival and growth of piglets born to Meishan × Yorkshire crossbred gilts.     

Direct and maternal breed effects on growth and milk intake of piglets: Meishan versus Dutch breeds

Cross fostering techniques were used to evaluate pre-natal (direct genetic and maternal) and post-natal (maternal) breed effects in Meishan and Dutch breeds on milk intake and growth of piglets during the suckling period and growth after weaning. Meishan as well as Dutch sows nursed mixed litters of Meishan and Dutch piglets. Birth weight of Dutch as compared to Meishan piglets was 56% higher. The effects of this birth weight difference on milk intake and growth of piglets were studied. Data on 44 mixed litters nursed by 21 Dutch and 23 Meishan sows were available.At an average birth weight difference, growth rate from birth to 21 and 21–35 d was 25 and 31% higher for Dutch than for Meishan piglets respectively, while milk intake per piglet at days 13 and 30 of lactation was 38 and 36% higher, respectively. Differences between Dutch and Meishan sows were small.Higher growth during the suckling period of Dutch as compared to Meishan piglets was mainly caused by their higher birth weight. Results indicate that Meishan sows have good maternal characteristics, i.e. significantly lower piglet mortality and the ability to raise also the heavier, more demanding Dutch piglets.     

Characterization of microbial populations and volatile fatty acid concentrations in the jejunum,ileum, and cecum of pigs weaned at 17 vs 24 days of age

In a series of five 17-d replicate trials, a total of 54 cannulated and 12 noncannulated pigs were used to determine the effects of weaning age (17 d or 24 d) on pH, dry matter percentage, aerobic and anaerobic microflora, lactate, and volatile fatty acid (VFA) concentrations in the jejunum, ileum, and cecum of weanling pigs. At -14 d of age, cannulated pigs were surgically fitted with T-cannulas in the jejunum (n = 20), ileum (n = 18), or cecum (n = 16). Upon weaning, cannulated pigs were individually caged in an environmentally controlled room with ad libitum access to a phase starter diet and water. Noncannulated pigs were killed at weaning and samples were collected from the jejunum, ileum, and cecum. Digesta and fecal swabs from cannulated pigs were collected twice weekly. The pH of cecal contents was lower (P < 0.05) and dry matter percentage was greater (P < 0.05) than those ofjejunal or ileal contents. Pigs weaned at 24 d of age had increased (P < 0.05) E. coli populations 3 d postweaning compared to preweaning populations, regardless of site of collection, whereas this increase was not observed in pigs weaned at 17 d of age. Unweaned pigs maintained higher (P < 0.05) lactobacilli populations compared to weaned pigs; however, populations declined (P < 0.05) in both groups by 3 d postweaning, with pigs weaned at 24 d of age having lactobacilli populations greater than pigs weaned at 17 d of age. Fecal populations of E. coli and lactobacilli declined (P < 0.05), whereas fecal bifidobacteria populations increased (P < 0.05) postweaning, regardless of weaning age. Concentrations of total fecal anaerobes declined (P < 0.05) in pigs weaned at 17 d of age but were maintained in pigs weaned at 24 d of age. Volatile fatty acid concentrations were greater (P < 0.05) in the cecum than in the jejunum or ileum, and acetic acid concentrations decreased (P < 0.05) postweaning regardless of weaning age. A tendency for L+ lactate concentrations to be greater (P < 0.07) in the ileum and jejunum vs the cecum was observed. Results indicate that weaning and weaning age have significant effects on microbial populations and VFA concentrations.     

高精料日粮对山羊瘤胃和盲肠发酵及生物胺生成与吸收的影响研究

本实验旨在探究饲喂高精料日粮对山羊瘤胃和盲肠发酵、生物胺生成与吸收的影响研究。试验选用6头装有永久性瘤胃瘘管的雄性波杂山羊,随机分成低精料组与高精料组,实验期24 d。结果显示,与低精料组相比,饲喂高精料日粮的山羊瘤胃液中总挥发性脂肪酸、乙酸、丙酸、丁酸、戊酸、总支链脂肪酸、酪胺、腐胺、组胺、甲胺和色胺浓度显著性增加(P<0.05),而瘤胃pH和乙丙比显著降低(P<0.05);饲喂高精料日粮的山羊盲肠内容物中的乙酸、丙酸、总挥发性脂肪酸浓度和上述5种生物胺浓度显著增加(P<0.05);同时,瘤胃和盲肠静脉血中的上述5种生物胺的浓度显著提高(P<0.05)。相关性分析结果表明,瘤胃液中酪胺、腐胺、甲胺和色胺浓度与瘤胃静脉血所对应的生物胺浓度呈显著正相关(P<0.05),且盲肠内容物中酪胺、腐胺、甲胺和色胺与盲肠静脉血中对应的生物胺的浓度呈显著正相关(P<0.05)。结果说明,饲喂高精料日粮促进了山羊瘤胃和盲肠发酵,提高了瘤胃与盲肠内容物中生物胺浓度,暗示高精料日粮可能提高消化道上皮的通透性,促进消化道上皮对生物胺的吸收。     

Screening for the effects of natural plant extracts at different pH on in vitro rumen microbial fermentation of a high-concentrate diet for beef cattle

Six natural plant extracts and three secondary plant metabolites were tested at five doses (0, 0.3, 3, 30, and 300 mg/L) and two different pH (7.0 and 5.5) in a duplicate 9 x 5 x 2 factorial arrangement of treatments to determine their effects on in vitro microbial fermentation using ruminal fluid from heifers fed a high-concentrate finishing diet. Treatments were extracts of garlic (GAR), cinnamon (CIN), yucca (YUC), anise (ANI), oregano (ORE), and capsicum (CAP) and pure cinnamaldehyde (CDH), anethole (ATL), and eugenol (EUG). Each treatment was tested in triplicate and in two periods. Fifty milliliters of a 1:1 ruminal fluid-to-buffer solution were introduced into polypropylene tubes supplied with 0.5 g of DM of a 10:90 forage:concentrate diet (15.4% CP, 16.0% NDF; DM basis) and incubated for 24 h at 39 degrees C. Samples were collected for ammonia N and VFA concentrations. The decrease in pH from 7.0 to 5.5 resulted in lower (P < 0.05) total VFA, ammonia N, branched-chain VFA concentration, acetate proportion, and acetate:propionate, and in a higher (P < 0.05) propionate proportion. The interaction between pH and doses was significant for all measurements, except for ATL and CDH for butyrate, ATL and EUG for acetate:propionate ratio, and ORE for ammonia N concentration. The high dose of all plant extracts decreased (P < 0.05) total VFA concentrations. When pH was 7.0, ATL, GAR, CAP, and CDH decreased (P < 0.05) total VFA concentration, and ANI, ORE, CIN, CAP, and CDH increased (P < 0.05) the acetate:propionate. The CIN, GAR, CAP, CDH, ORE, and YUC decreased (P < 0.05), and EUG, ANI, and ATL increased (P < 0.05) ammonia N concentration. The effects of plant extracts on the fermentation profile when pH was 7.0 were not favorable for beef production. In contrast, when pH was 5.5, total VFA concentration did not change (ATL, ANI, ORE, and CIN) or increased (P < 0.05) (EUG, GAR, CAP, CDH, and YUC), and the acetate:propionate (ORE, GAR, CAP, CDH, and YUC) decreased (P < 0.05), which would be favorable for beef production. Ammonia N (ATL, ANI, CIN, GAR, CAP, and CDH) and branched-chain VFA (ATL, EUG, ANI, ORE, CAP, and CDH) concentrations also were decreased (P < 0.05), suggesting that deamination was inhibited. Results indicate that the effects of plant extracts on ruminal fermentation in beef cattle diets may differ depending on ruminal pH. When pH was 5.5, GAR, CAP, YUC, and CDH altered ruminal microbial fermentation in favor of propionate, which is more energetically efficient.     

Effects of dietary Forsythia suspensa extract supplementation to lactating sows and nursery pigs on post-weaning performance,antioxidant capacity,nutrient digestibility,immunoglobulins, and intestinal health

The aim of this study was to determine the effect of dietary Forsythia suspensa extract (FSE) supplementation to lactating sows and nursery pigs on post-weaning performance, antioxidant capacity, immunoglobulins, and intestinal health. Based on backfat, body weight (BW), and parity, 24 gestating sows (Landrace × Yorkshire) with average parity of 3.38 ± 0.61 and BW of 234 ± 6.81 kg were allotted into two dietary treatments (control vs. 100 mg/kg FSE) with 12 sows per treatment from day 107 of gestation to day 21 of lactation. After weaning, based on the initial BW and source litter, 192 nursery pigs (Duroc × [Landrace × Yorkshire], average BW of 6.98 ± 0.32 kg, weaned at day 21) were allotted into four dietary treatments with eight replicate pens per treatment, six pigs per pen for a 4-wk study. The treatments included the following: 1) CC (sows and their piglets both fed control diet); 2) CF (sows fed control diet and their piglets fed FSE diet [containing 100 mg/kg FSE]); 3) FC (sows fed FSE diet and their piglets fed control diet); and 4) FF (sows and their piglets both fed FSE diet). The MIXED procedures of SAS for a split-plot arrangement with sow diet as the whole plot and nursery diet as split plot were used to analyze the data. After weaning, piglets from FSE-fed sows had improved (P < 0.05) average daily gain and feed efficiency, and lower (P < 0.05) diarrhea rate in overall (day 1 to 28) compared with those from sows fed control diet. Piglets from FSE-fed sows also had higher (P < 0.05) contents of immunoglobulin G (IgG), growth hormone, superoxide dismutase (SOD), total antioxidant capacity in serum, villus height in ileum, and villus height to crypt depth ratio in jejunum, as well as lower (P < 0.05) content of malondialdehyde (MDA) in serum and crypt depth in ileum compared with those from sows fed control diet. Piglets fed FSE during nursery had increased (P < 0.05) concentrations of IgG, SOD, and catalase, and decreased (P < 0.05) MDA and tumor nuclear factor-α levels in serum compared with those fed control diet during nursery. Piglets from FC group had increased (P < 0.05) protein expression of occludin in jejunal mucosa and relative abundance of Lactobacillus on genus level in colon compared with those from CC group. In conclusion, for the performance and intestinal health, diets supplemented with FSE during lactation phase seemed more efficient to alleviate weaning stress than the nursery phase. In terms of the antioxidant status and immunoglobulins, FSE supplemented in both phases were efficient for nursery pigs.     

Determination of volatile fatty acids in the blood plasma of cattle before and after an infusion of propionate and butyrate

Before and after infusion of propionate and butyrate the concentrations of volatile fatty acids (VFA) in the blood of heifers were determined by gas chromatography, in order to indicate activity and regulation of the carbohydrate metabolism. 14 heifers were loaded after food deprivation with intravenous infusions of propionate and butyrate. Concentrations of acetate, propionate, isobutyrate, butyrate, and valerate were measured in blood samples which were taken later on. The methods used for clearance and extraction as well as for gas chromatographic analysis are described. Retention times and blood concentrations are given for each VFA. Concentrations prior to infusion were for: acetate 10.14 +/- 2.51 microliters/ml; propionate 0.42 +/- 0.35 microliters/ml; iso-butyrate 3.72 +/- 1.37 microliters/ml; butyrate 3.44 +/- 0.68 microliters/ml blood plasma. The concentrations of the infused VFA showed a 100 (butyrate) to 1000 (propionate) fold increase followed by a subsequent decrease to the initial values. These investigations on the profile of VFA elucidated criteria of the energy metabolism.     

SLA-DQA基因在大约克、苏太和梅山猪断奶仔猪中组织表达差异分析

本研究旨在通过对SLA-DQA基因在苏太猪大肠杆菌F18菌株抗性群体和大约克猪、梅山猪断奶仔猪各组织间的表达规律及其在3个群体间表达差异的分析,探讨SLA-DQA基因与国内外猪品种断奶仔猪不同水平免疫机能和大肠杆菌抗性间的潜在关系。研究结果显示,SLA-DQA基因在3个猪群体所检测的11个组织中均表达,并且表达规律基本一致,在肺脏、脾脏、淋巴结等免疫器官中的表达量较高,在胃、十二指肠、空肠等消化道中表达量居中。SLA-DQA基因在苏太猪所有检测组织中的表达量均最高,大约克中次之,梅山猪中表达量最低。尤其在肺脏、淋巴结和胸腺3个组织中,SLA-DQA基因在苏太猪中的表达量均显著高于其在梅山猪中的表达量;在胸腺组织中,SLA-DQA基因在苏太猪中的表达量显著高于大约克猪。研究结果表明,SA-DQA基因在断奶仔猪受大肠杆菌F18菌株病原菌侵袭后引起的一系列生理变化和应答过程中发挥着重要的抗原递呈和激发机体免疫的作用。     

饲粮中添加不同水平L-精氨酸对妊娠母猪繁殖性能及血液生化指标的影响

本研究探讨饲粮中添加不同水平L-精氨酸(L-Arg)对母猪繁殖性能及血浆一氧化氮相关指标的影响。试验选择36头2胎次母猪(长白×大约克),随机分为4组,每组9头母猪。各组饲粮分别在基础饲粮中添加0 L-Arg+1.70%L-丙氨酸(L-Ala)(0 L-Arg组)、0.4%L-Arg+1.02%L-Ala(0.4%L-Arg组)、0.7%L-Arg+0.51%L-Ala(0.7%L-Arg组)和1.0%L-Arg+0 L-Ala(1.0%L-Arg组),各组添加L-Ala以满足等氮平衡需要。试验期从母猪配种当天到分娩。结果表明:1.0%L-Arg组比0 L-Arg组显著提高了窝产活仔数和初生窝重(P<0.05),随着饲粮中L-Arg水平的提高,窝产仔总数和初生个体重有上升趋势(P>0.05);母猪妊娠第30、60和90天,1.0%L-Arg组血浆中Arg、鸟氨酸含量均显著或极显著高于0.7%、0.4%、0 L-Arg组(P<0.05或P<0.01);母猪妊娠第90天,各组间的血浆脯氨酸含量均有极显著差异(P<0.01),但第30、60天差异均不显著(P>0.05);母猪妊娠第30、60、90天,1.0%L-Arg组血浆一氧化氮含量和第90天血浆总一氧化氮合酶(TNOS)、诱导型一氧化氮合酶(iNOS)活性均显著或极显著高于0.7%、0.4%、0 L-Arg组(P<0.05或P<0.01)。经回归分析,母猪的窝产仔总数、窝产活仔数、初生窝重、血浆中各氨基酸、一氧化氮含量及TNOS和iNOS的活性与饲粮L-Arg水平均有显著或极显著的线性关系(P<0.05或P<0.01)。结果提示,饲粮中L-Arg水平变化对母猪妊娠后期血液生化指标影响明显,饲粮中添加1.0%L-Arg对提高母猪繁殖性能效果最佳。     

早期断奶对仔猪空肠和回肠兴奋性氨基酸载体1表达的影响

本试验旨在研究仔猪出生后10~20 d,早期断奶仔猪小肠谷氨酸转运载体基因表达情况与哺乳仔猪的差异。试验分别从40头不同母猪的仔猪中各选出体重相近,10日龄的"杜×长×大"三元杂交仔猪1头,共40头仔猪,随机不配对分为2组,每组20头仔猪,对照组(哺乳组)为哺乳仔猪,随母猪喂养;试验组(断奶组)为断奶仔猪,隔离断奶饲养;试验期10 d。饲养结束,每组随机取12只仔猪,宰杀取空肠和回肠,测定谷氨酸转运载体兴奋性氨基酸转运载体1(EAAC1)蛋白质表达情况和游离氨基酸含量。结果显示,断奶显著降低了仔猪空肠和回肠EAAC1(57和73 ku)及其相关蛋白谷氨酸转运联合蛋白(GTRAP3-18)(50 ku)的蛋白质和mRNA表达量(P0.05)。断奶提高了仔猪空肠游离谷氨酸和总氨基酸含量,却降低了仔猪回肠游离谷氨酸和总氨基酸含量,差异显著(P0.05)。结果提示,早期断奶降低EAAC1和GTRAP3-18的蛋白质含量,这可能与早期断奶仔猪遭受营养谷氨酸缺乏导致的肠道氨基酸吸收转运障碍有关。     

Effect of feeding organic acids on selected intestinal content measurements at varying times postweaning in pigs.

Pigs weaned at 21 d of age (n = 72) were fed a 20% CP corn-soybean meal-based diet (control) with 1.5% fumaric or 1.5% citric acid added to observe the effect of these acids on the pH, chloride ion concentration (Cl-), VFA profile, and microflora population in the stomach, jejunum, cecum, and lower colon contents at -2, 0, 3, 7, 14, and 21 d postweaning. Feeding organic acids had no appreciable effect (P greater than .10) on stomach jejunum, cecum, or lower colon pH, Cl-, VFA profile, or microflora populations, except for increasing the concentration of fumaric acid in the stomachs of pigs fed fumaric acid. The pH of the gastrointestinal tract generally decreased from -2 to 21 d postweaning with no corresponding change in Cl- over time. No age effects on total anaerobic culture counts were observed except in the stomach, where counts decreased from -2 to 3 d postweaning. Clostridia counts generally decreased after weaning in all intestinal sections. Lactobacillus counts were usually lower at d 0 and 3 and greatest at d 7 postweaning in the stomach, jejunum, and lower colon, but no age effect was observed for concentration of cecum lactobacilli. Escherichia coli counts generally increased after weaning to 3 and 7 d postweaning. Intestinal content measurements were affected by postweaning age but were not affected by feeding organic acids.     

Breed and age affect baseline immune traits, cortisol, and performance in growing pigs

It was hypothesized in these studies that differences would exist in baseline immune and performance measures among different breeds of pigs, and that these differences would be affected by age of the pig. Baseline immune, plasma cortisol (CORT) concentrations, and performance measures were determined among Berkshire (n = 36), Duroc (n = 18), Meishan (n = 54), Landrace x Yorkshire (White X; n = 36), and Yorkshire (n = 36) pigs at 4, 8, and 12 wk of age. All piglets were weaned at 17 to 21 d of age and moved to a common nursery environment. Total white blood cell (WBC), leukocyte differential, plasma CORT, immunoglobulin G (IgG) concentrations, natural killer cytotoxicity, neutrophil phagocytosis (PHAGO), and chemotaxis (CHTX) were evaluated. At all ages, plasma CORT was greatest in Meishan pigs, and least in Yorkshires (P < 0.05). Plasma IgG increased with age for all breeds (age: P < 0.01; breed x age: P < 0.005), except that in Meishans, IgG decreased. Natural killer cytotoxicity was greatest (P < 0.05) among Meishan pigs. There were breed x age interactions for neutrophil PHAGO (P < 0.001) and CHTX (P < 0.001). Overall, Yorkshire pigs showed the greatest (P < 0.05) percentage of PHAGO but the least (P < 0.05) CHTX. White X pigs had the greatest (P < 0.05) CHTX response. Berkshire pigs had the greatest (P < 0.001) numbers of neutrophils. At 12 wk of age, Meishan pigs had the least BW gain (P < 0.001), and Durocs had the greatest G:F (P < 0.001). There were no significant sex differences for immune (P > or = 0.15), performance (P > or = 0.20), or CORT (P = 0.70) measures. Pig breed and age influenced both baseline immune measures and plasma CORT in growing pigs, suggesting that pig breed and age are important factors influencing the response to various stressors or infectious challenges.     

生长育肥猪后肠纤维分解菌的数量及微生物发酵作用

本试验采用严格厌氧微生物学方法 ,对生长肥育猪的盲肠、结肠和直肠内容物中总厌氧菌和纤维分解菌的数量、纤维素酶活性、氨态氮和VFA含量进行了测定。结果表明 ,盲肠和直肠内容物中纤维分解菌的数量显著高于结肠(P<0.01) ;盲肠内容物中羧甲基纤维素酶活性最高 ,其次是结肠 ,直肠最低(P<0.05) ;直肠和盲肠的氨态氮浓度显著高于结肠(P<0.05) ;盲肠、结肠和直肠的总VFA含量分别为82.79、154.47和143.80mmol/L ;乙酸的摩尔百分比为盲肠>结肠>直肠 ;丙酸的摩尔百分比无明显改变 ;丁酸的摩尔百分比为盲肠<结肠<直肠(P>0.05)。本试验证明 ,饲喂玉米—豆粕型日粮的生长肥育猪后肠中存在相当数量的纤维分解菌 ,盲肠、结肠和直肠内容物中纤维分解菌的数量分别占可培养微生物区系的8.6 %、3.1 %和22.1 %。后肠微生物发酵类型为乙酸发酵型。     

槲皮素对PEDV感染幼龄仔猪肠道形态、抗氧化功能及空肠脂质代谢基因表达的影响

【目的】 通过研究槲皮素对猪流行性腹泻病毒（PEDV）感染仔猪肠道形态、肠道抗氧化功能及空肠脂质代谢相关基因相对表达量的影响,旨在探讨槲皮素对PEDV感染仔猪肠道的保护作用。【方法】 选取18头健康的7日龄断奶仔猪,随机分为3组：对照组、PEDV组和槲皮素＋PEDV组,每组6个重复,每个重复1头猪。试验期8 d,于试验第0~7天,对槲皮素＋PEDV组仔猪每天口腔灌服10 mg/kg BW的槲皮素,其余组灌服等体积的人工奶。于试验第5天晚上给PEDV组和槲皮素＋PEDV组仔猪口腔灌服10^4.5TCID₅₀的PEDV,对照组仔猪灌服相同体积的PBS溶液。于试验第8天早上屠宰,取仔猪十二指肠、空肠、回肠及结肠组织样品进行检测。【结果】 与对照组相比,PEDV组仔猪空肠和回肠的绒毛高度以及绒毛高度与隐窝深度比值极显著降低（P<0.01）,空肠、回肠和结肠中谷胱甘肽过氧化物酶（GSH-Px）和总超氧化物歧化酶（T-SOD）的活力显著降低（P<0.05）,十二指肠、空肠、回肠和结肠中过氧化氢酶（CAT）的活力显著降低（P<0.05）,回肠和结肠中丙二醛（MDA）的含量显著升高（P<0.05）,空肠中载脂蛋白A1（APOA1）、载脂蛋白B （APOB）、载脂蛋白C2（APOC2）、脂肪酸结合蛋白2（FABP2）、酰基辅酶A合成酶长链家族成员3（ACSL-3）和脂肪酸合酶（FASN）基因的相对表达量极显著下调（P<0.01）。与PEDV组相比,槲皮素＋PEDV组仔猪空肠和回肠的绒毛高度以及绒毛高度与隐窝深度比值极显著提高（P<0.01）,空肠、回肠和结肠中GSH-Px和T-SOD的活力显著提高（P<0.05）,十二指肠、空肠和结肠中CAT的活力显著提高（P<0.05）,回肠和结肠中MDA的含量显著降低（P<0.05）,空肠中APOB、FABP2和FASN基因的相对表达量极显著上调（P<0.01）。【结论】 添加槲皮素可有效缓解PEDV感染导致的仔猪肠道损伤,提高仔猪肠道抗氧化能力以及空肠脂质代谢的能力。