Small intestinal morphology in weaned piglets fed a diet containing spray-dried porcine plasma

The hypothesis tested in this study was that the reported beneficial effects of spray-dried porcine plasma (SDPP) on piglet post-weaning performance and health are associated with a trophic effect on small intestinal mucosa. At 24 days of age, the piglets of seven sows were assigned to one of three treatment groups. One group continued to be suckled. The other two groups were weaned and offered a diet containing either 15 per cent SDPP or casein. From each treatment group, one piglet was anaesthetised and samples were taken from the small intestinal wall at 26, 28 and 31 days of age. There were no significant effects of SDPP versus casein on villus length. On average, there was less mitotic activity in the SDPP -fed piglets than in those fed casein on days 4 and 7 after weaning. As less mitotic activity leads to less immature enterocytes, this may provide a mechanism for the reported beneficial effects of SDPP on performance and health.     

Commercial spray-dried porcine plasma does not transmit porcine circovirus type 2 in weaned pigs challenged with porcine reproductive and respiratory syndrome virus

The objective of this study was to evaluate if spray dried porcine plasma (SDPP) containing porcine circovirus type 2 (PCV2) genome supplemented in feed could transmit PCV2 to pigs challenged with porcine reproductive and respiratory syndrome virus (PRRSV). Twenty-three PRRSV-free pigs, non-viraemic for PCV2, were housed in bio-safety level 3 facilities and assigned to four groups in a 2×2 factorial design consisting of PRRSV challenge and a negative control. The diet contained 0 or 8kg SDPP per 100kg of feed. PRRSV challenge groups were inoculated intranasally with 2mL of a suspension containing 10(6) TCID(50)/mL PRRSV. The SDPP used in the study contained 7.56×10(5) PCV2 genome copies per gram. Dietary treatments were fed from 4days prior to PRRSV inoculation until 28days post-inoculation (PI). All challenged pigs developed PRRSV viraemia by day 3PI and PRRSV antibodies were detected in sera by day 14PI, with no difference between diet treatments. Neither PRRSV viraemia nor seroconversion was observed in non-challenged pigs. PCV2 was not detected in the serum of any pigs throughout the experimental period. SDPP containing the PCV2 genome supplemented in feed did not result in PCV2 transmission to either healthy or PRRSV-infected pigs under these experimental conditions.     

Effects of dietary supplementation of lipid‐encapsulated zinc oxide on colibacillosis,growth and intestinal morphology in weaned piglets challenged with enterotoxigenic Escherichia coli

This study was aimed to evaluate the effect of dietary supplementation of lipid‐encapsulated (coated) zinc oxide ZnO on post‐weaning diarrhea (colibacillosis) in weaned piglets challenged with enterotoxigenic Escherichia coli (ETEC). Thirty‐two 35‐day‐old weaned piglets were orally challenged with 3 × 10¹⁰ colony forming units of ETEC K88 while eight piglets received no challenge (control). Each eight challenged piglets received a diet containing 100 ppm ZnO (low ZnO), 2500 ppm ZnO (high ZnO) or 100 ppm of lipid (10%)‐coated ZnO (coated ZnO) for 7 days; control pigs received the low ZnO diet. Daily gain, goblet cell density in the villi of the duodenum, jejunum and ileum, and villus height in the jejunum and ileum, which decreased due to the challenge, were equally greater in the coated ZnO and high ZnO groups versus low ZnO group. Fecal consistency score, serum interleukin‐8 concentration, subjective score of fecal E. coli shedding, and digesta pH in the stomach, jejunum and ileum, which increased due to the challenge, were equally low in the coated ZnO and high ZnO groups versus low ZnO. Results suggest that a low level of coated ZnO might well substitute for a pharmacological level of native ZnO in dietary supplementation to alleviate colibacillosis of weaned piglets.     

Evaluation of the effect of 3 probiotics on experimental Escherichia coli enterotoxaemia in weaned piglets.

In this report the efficacy of 3 different probiotics (Bacillus cereus "toyoi", Lactobacillus spp. and Streptococcus faecium) was investigated. They were supplemented in the food of recently weaned piglets that were orally infected with E. coli O141 K85ab. Supplementation could not prevent mortality and clinical symptoms nor reduce the faecal excretion of hemolytic E. coli. The possible explanations for the unsatisfying results are various.     

鼠李糖乳杆菌LGG对大肠杆菌K88^＋攻毒的断奶仔猪肠道菌群的影响

美国Sherwood Gorbach和Barry Goldin于1983年从健康人体中成功分离出一种新的乳酸菌-鼠李糖乳杆菌并将其命名为LGG.1985年Sherwood Gorbach和Barry Goldin为LGG申请专利,1987年芬兰维利奥有限公司与两位学者达成协议,由该公司负责LGG的研发和生产,并用于LGG的全球惟一授权[1].     

Effects of dietary Clostridium butyricum supplementation on growth performance,intestinal development,and immune response of weaned piglets challenged with lipopolysaccharide

Background: Weanling pigs, with immature immune system and physiological function, usually experience postweaning diarrhea. This study determined the effects of dietary Clostridium butyricum supplementation on growth performance, diarrhea, and immunity of weaned pigs challenged with lipopolysaccharide(LPS).Methods: In Experiment(Exp.) 1,144 weaned piglets were weaned at 21 d and randomly assigned to six groups,with six replicates per group and four pigs per replicate, receiving a control diet(CON) or diet supplemented with antibiotics(AB) or C. butyricum(CB)(0.1%, 0.2%, 0.4%, or 0.8%), respectively. All diets in Exp. 1 were a highly digestible basal diet, with 3,000 mg/kg zinc oxide supplied in the first 2 wk only. In Exp. 2, 180 piglets were weaned at 21 d and randomly assigned to five groups, with six replicates per group and six pigs per replicate, receiving CON, AB, or CB(0.2%, 0.4%, or 0.6%) diets. The digestibility of diets was lower than those in Exp. 1, and did not include zinc oxide. At 36 d of Exp. 2, 12 piglets were selected from each of the CON and 0.4% CB groups, six piglets were intraperitoneally injected with LPS(50 μg/kg body weight) and the other six piglets with normal saline;animals were killed at 4 h after injection to collect blood, intestine, and digesta samples for biochemical analysis.Results: In Exp. 1, CB and AB diets had no effect on growth performance of piglets. In Exp. 2, 0.4% CB decreased feed-gain ratio(P 0.1), diarrhea score(P 0.05), and increased duodenal, jejunal, and ileal villus height and jejunal villus height/crypt depth(P 0.05). The 0.4% CB decreased the plasma tumor necrosis factor(TNF) α(P 0.05) but increased ileal mucosa IL-10 and TLR2 mRNA expression(P 0.05). Furthermore, 0.4% CB altered the microbial profile, with Bacillus and Ruminococcaceae UGG-003 at genus level and Lactobacillus casei and Parasutterella secunda at species level were higher than CON in colonic content(P 0.05).Conclusions: Dietary C. butyricum supplementation had positive effects on growth of weaned piglets with less digestible diets. There was a tendency to reduce the feed-gain ratio, which could reduce feed costs in pig production. Moreover, C. butyricum decreased post-weaning diarrhea by improving the intestinal morphology,intestinal microflora profile, and immune function.     

The effects of thermal environment and spray-dried plasma on the acute-phase response of pigs challenged with lipopolysaccharide

Forty barrows (TR4 x C22) were weaned at 17 d of age (BW = 6.27 +/- 0.30 kg), housed (two pigs/pen) in a thermal-neutral environment (TN; constant 26.7 degrees C), and fed diets with or without 7% (as-fed basis) spray-dried plasma (SDP). On d 7, one pig/ pen was moved into a cold environment (CE; constant 15.6 degrees C). Pigs were fitted with jugular catheters on d 11. On d 12, 16 pigs per environment (eight pigs per dietary treatment) were challenged i.v. with 75 microg of lipopolysaccharide (LPS)/kg of BW. Blood samples were collected over a 4.5-h period. Pigs were then killed and tissue samples were harvested for messenger RNA (mRNA) analysis. From d 0 to 7, pigs fed SDP diets had a lower gain:feed ratio (G/F) than pigs fed no SDP (533 +/- 14 vs. 585 +/- 17 g/kg; P < 0.03). Pigs housed in the CE consumed more feed and had a lower G/F than pigs housed in TN from d 7 to 11 (P < 0.001). There were no environment x diet interactions from d 7 to 11 (P > 0.78). Baseline concentrations of serum ACTH and cortisol were lower in the TN pigs than in the CE pigs (P < 0.001). Pigs fed diets without SDP had lower serum cortisol concentrations over the 4.5-h period than pigs fed SDP (time x diet, P < 0.001). Serum concentrations of tumor necrosis factor-alpha (TNF-alpha) were highest for pigs consuming SDP in the CE, whereas there were no differences among the other treatments (time x diet x environment, P < 0.02). Pigs housed in the CE had higher serum interleukin-1beta (IL-1beta) (P < 0.001) and interleukin-6 (IL-6; P < 0.001) than TN pigs. Pigs fed SDP also had slightly higher serum IL-1beta concentrations (P < 0.10) and higher (P < 0.001) IL-6 concentrations than pigs fed no SDP. Pigs fed SDP had 9% lower liver and 13% lower thymus mRNA expression of tumor necrosis factor-alpha (TNF-alpha) than pigs that consumed no SDP (P < 0.06). Liver IL-1beta, IL-6, and LPS-binding protein mRNA were higher in the CE than in the TN (P < 0.03, P < 0.001, and P < 0.05; respectively). In addition, spleen TNF-alpha (P < 0.03) and IL-6 (P < 0.01) mRNA levels were higher in the CE than in the TN. Pigs consuming SDP and challenged with LPS responded with elevated serum concentrations of cortisol and cytokines compared with pigs fed diets with no SDP. Housing pigs in a CE increased the baseline concentrations of ACTH and cortisol, and when coupled with an LPS challenge, resulted in elevated serum and tissue mRNA levels of cytokines. Cold stress and feeding SDP during a LPS challenge may result in increased stress and immune responses in young pigs.     

The effect of dietary supplementation with globin and spray-dried porcine plasma on performance,digestibility and histomorphological traits in broiler chickens

This study evaluated the effects of globin and spray-dried porcine plasma (SDPP) on growth performance, digestibility, nitrogen retention, energy retention efficiency (ERE) and intestinal morphology of broiler chickens. A total of 336-day-old male broiler chickens were reared from 1 to 40 days of age and fed 3 diets (8 replicates/diet, 14 birds/replicate) during 3 feeding phases: starter (1–12 days), grower (12–25 days) and finisher (25–40 days). Isonitrogenous diets were formulated by replacing gluten protein isolate contained in the control diet (C diet) with 2% (starter) or 1% (grower and finisher) spray-dried porcine plasma in the plasma diet (SDPP diet). The globin diet (G diet) was obtained by adding globin on the top of C diet at a dose of 0.08% for the whole rearing period. Total tract apparent digestibility (aD), nitrogen retention and ERE were assessed during the three growing phases. At 12  and 40 days of age, one bird per pen was slaughtered to sample gut, liver, spleen and bursa of Fabricius for histomorphological investigations. The SDPP diet increased body weights of chickens at 12 (+60 g; p < .001), 25 (+101 g; p < .001) and 40 days (+130 g; p = .018) of age compared to C and G diets. Also SDPP improved crude protein aD (+9.7%) and ERE (+12.3%) during the starter phase (p < .001). Dietary globin and SDPP inclusion did not affect either the gut morphology or the histopathological findings in birds at 12 and 40 days of age, despite a numerical (+6.90% and +7.40% respectively) villus height improvement in the SDPP group. Overall, these results confirm that dietary supplementation with SDPP and, to a lesser extent, with globin can improve growth performance and dietary protein and energy utilization in broiler chickens without effect on gut functionality.     

Spray-dried plasma improves growth performance and reduces inflammatory status of weaned pigs challenged with enterotoxigenic Escherichia coli K88

We investigated whether spray-dried plasma (SDP) improved growth and health of piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC). Forty-eight pigs weaned at 21 d (BW = 4.88 +/- 0.43 kg) received one of four diets containing 6% SDP or fish proteins (as-fed basis) either nonmedicated (SDP-NM and FP-NM diets) or medicated with 0 or 250 mg/kg of colistine + 500 mg/kg of amoxycycline (SDP-M and FP-M diets), for 15 d. On d 4, pigs were orally challenged with ETEC. On d 15, eight pigs per dietary group were killed, blood and saliva were collected for analysis of K88 fimbriae-specific immunoglobulin (Ig)-A, and jejunum was removed for villi preparation, histological analysis, and cytokine expression. The presence or absence of K88 receptors (K88+ and K88- pigs respectively) was determined by villous adhesion assay. Effects of protein source on ADG (P = 0.04) and ADFI (P < 0.01), as well of medication on ADFI (P < 0.02), of all pigs were observed. In sacrified pigs, there was an effect of protein source on ADG (P = 0.03) and ADFI (P < 0.001), as well an interaction between medication and presence of K88 receptor (P = 0.02) for feed:gain ratio. Plasma K88 specific IgA were low in all K88 pigs and higher in K88+ pigs fed FP-NM compared with all the other groups (P < 0.05), except SDP-M. An interaction was found among protein source, medication, and presence of K88 receptors (P = 0.04). Saliva IgA concentrations were high in all pigs fed FP-NM and low in all other pigs. Jejunum of pigs fed FP-NM showed some ulcerations, edema, and mild inflammatory cell infiltration (ICI). In pigs fed FP-M, edema was reduced. Conversely, only a mild ICI was observed in pigs fed SDP-NM and SDP-M. Crypt depth was increased in K88+ pigs fed SDP-NM and an interaction between protein source and presence of K88 receptors was observed (P < 0.05). Expressions of tumor necrosis factor-alpha and interleukin (IL)-8 were lower in pigs fed SDP-NM and SDP-M than in those fed FP-NM and FP-M, either K88- or K88+ (P < 0.01). In pigs fed FP diets, expression of IL-8 tended to increase (P = 0.08) in K88+ compared with K88- subjects. Expression of interferon-gamma increased in K88 and K88+ pigs fed FP-M as compared with other pigs (P < 0.01). These results indicate that feeding with SDP improved growth performance and protected against E. coli-induced inflammatory status, and suggest that use of SDP-NM can be considered a valid antibiotic alternative.     

Influence of dietary ingredients on in vitro inflammatory response of intestinal porcine epithelial cells challenged by an enterotoxigenic Escherichia coli (K88)

Enterotoxigenic Escherichia coli (ETEC) K88 is the main bacterial cause of diarrhea in piglets around weaning and the adhesion of ETEC to the intestinal mucosa is a prerequisite step for its colonization. In this study, the adhesion of a fimbriated ETEC and a non-fimbriated E. coli (NFEC) to the intestinal cells and the activation of the innate immune system were evaluated using a porcine intestinal epithelial cell line (IPEC-J2). The impact of several feedstuffs (wheat bran (WB); casein glycomacropeptide (CGMP); mannan-oligosaccharides (MOS); locust bean extract (LB) and Aspergillus oryzae fermentation extract (AO)) on ETEC attachment and the inflammatory response were also studied. The gene expression of TLR-4; TLR-5; IL-1β; IL-8; IL-10 and TNF-α were quantified using Cyclophilin-A, as a reference gene, and related to a non-challenged treatment. The fimbriated strain was markedly better than the non-fimbriated strain at adherence to intestinal cells and inducing an inflammatory response. All the feedstuffs studied were able to reduce the adhesion of ETEC, with the greatest decrease with CGMP or MOS at highest concentration. Regarding the inflammatory response, the highest dose of WB promoted the lowest relative expression of cytokines and chemokines. All tested feedstuffs were able to reduce the adhesion of ETEC to IPEC-J2 and interfere on the innate inflammatory response; however WB should be further studied according to the beneficial results on the intestinal inflammatory process evidenced in this study.     

Experimental infection with Escherichia coli O149:F4ac in weaned piglets

The outcome of experimental intestinal infections with enterotoxigenic Escherichia coli (ETEC) is dependent on several factors. An important factor is adhesion of the challenge strain to the intestinal mucosa. The test for susceptibility towards ETEC adhesion has so far been made by an intestinal adhesion test made after slaughter of piglets. However, in an experimental infection study with the purpose to obtain diarrhoeic piglets, it would be an advantage to test for susceptibility prior to experimentation. The Mucin 4 gene on porcine chromosome 13 has been proposed as a candidate gene for the production of the specific ETEC F4ab/ac receptor, and a DNA marker-based test has been developed to allow genotyping for ETEC F4ab/ac resistance/susceptibility [J?rgensen, C.B., Cirera, S., Archibald, A.L., Anderson, L., Fredholm, M., Edfors-Lilja, I., 2004. Porcine polymorphisms and methods for detecting them. International application published under the patent cooperation treaty (PCT). PCT/DK2003/000807 or WO2004/048606-A2]. The aim of this study was to test an experimental model for ETEC O149:F4ac-induced diarrhoea in piglets, selected for susceptibility towards ETEC O149:F4ac adhesion prior to experimentation using a DNA marker-based test. Sixty-two healthy 25-32 days old recently weaned Danish crossbred piglets were used. All piglets were tested prior to experimentation for susceptibility or resistance towards ETEC O149:F4ac adhesion. Thirty-nine piglets, both susceptible and resistant, were oro-gastric intubated with 10(9)CFU of ETEC O149:F4ac and 23 age-matched piglets, both susceptible and resistant, were used as non-infected controls. Of susceptible piglets, challenged with ETEC O149:F4ac, 74% had ETEC O149:F4ac-associated diarrhoea first day after first challenge, which were significantly higher relatively to the resistant and challenged piglets where 20% had diarrhoea (p=0.04). This study suggests a model for experimental ETEC induced diarrhoea.     

Small intestinal morphology and disaccharidase activities in early-weaned piglets fed a diet containing spray-dried porcine plasma

The purpose of this study was to test whether dietary spray-dried porcine plasma (SDPP) in early-weaned piglets prevents small intestinal villus atrophy by trophic or protective activity. Fifty-four weaned, 18-day-old piglets were used to determine the effect of dietary SDPP on small intestinal villus length, crypt depth, enterocyt mitotic activity and brush border enzyme activities during the first week after weaning. The piglets were offered a diet containing either 8% SDPP or 8% casein. At 2 and 7 days after weaning, piglets were anaesthetized to provide samples of the small intestinal wall and killed immediately afterwards. There were no differences in daily gain and daily feed intake between the two dietary treatments. At day 2 after weaning, all piglets showed a marked reduction in villus height when compared with baseline values. In all piglets, small intestinal enterocyte mitotic activity had decreased by day 2 and was increased again on day 7. There were no significant effects of dietary SDPP on small intestinal villus length, crypt depth and enterocyt mitotic activity. This indicates that SDPP has no trophic effect on the small intestinal mucosa and that it does not protect against the damaging effect on the small intestinal villi that is associated with the process of weaning. There was no effect of SDPP on lactase-, sucrase- or maltase-specific activities that are a measure of the digestive function of the small intestine. It can be concluded that SDPP versus casein has no effect on small intestinal morphology and disaccharidase activities in early weaned piglets kept under low infection pressure.     

Weaning of piglets. Effects of an exposure to a pathogenic strain of Escherichia coli

The influence of weaning on day 32 and a simultaneous challenge with a pathogenic strain of Escherichia coli was studied in eight piglets. Another nine weaned but non-infected piglets were used as controls. The distribution of peripheral blood mononuclear cells (PBMC) into subpopulations, as well as their response when stimulated in vitro by pokeweed mitogen, changed in a similar manner during post-weaning in both groups. In contrast, superior responses were recorded for PBMC collected from the challenged pigs when stimulated in vitro with concanavalin A and with a heat-inactivated extract of the E. coli strain used for infection, respectively. Despite a successful colonization of the challenge strain, no clinical signs of disease were recorded. Nor did the daily weight gain or the number of E. coli, enterococci, or Clostridium perfringens excreted per gram of faeces differ between the groups. However, the weaning induced a marked decrease in the diversity of coliforms in individual piglets, which announced a reduced colonization resistance of that flora. Also, a decreased homogeneity between coliform floras of different piglets was observed following weaning. The decreased homogeneity indicated that different strains of E. coli were predominant in different animals, which may in turn facilitate the spread of pathogenic strains. The enteric changes were more pronounced and lasted longer in infected animals. Still, the influence of a sole pathogenic strain of E. coli was not enough to induce post-weaning diarrhoea.     

The effect of dietary tryptophan levels on oxidative stress of liver induced by diquat in weaned piglets

Oxidative stress can induce abnormal tryptophan metabolism. The present study was mainly conducted to determine the effect of dietary tryptophan levels on oxidative stress in the liver of weaned pigs challenged by diquat. A total of 36 PIC piglets weaned at 21 days of age were randomly allotted to 1 of 3 diets containing dietary tryptophan levels of 0.18, 0.30, and 0.45% for 14 d. On day 8, the piglets were injected intraperitoneally with sterile 0.9% NaCl solution or diquat (10 mg/kg body weight). During the first 7 d of trial, increasing dietary tryptophan levels enhanced average daily gain (P = 0.09) and average daily feed intake (P = 0.08), and decreased the feed efficiency (P < 0.05) of piglets. The growth performance was decreased by diquat injection (P < 0.05). Diquat injection also decreased the activities of the superoxide dismutase (SOD) and glutathione peroxidase (GPx) in the plasma and liver (P < 0.05), increased plasma malondialdehyde (MDA) (P < 0.05) and urea nitrogen (P < 0.05) concentrations, and enhanced MDA concentration (P = 0.09) and tryptophan 2,3-dioxygenase (TDO) activity (P = 0.07) in liver of piglets. Increasing dietary tryptophan levels could attenuate the effects of diquat injection on the MDA (P = 0.06) concentration and the activities of SOD (P = 0.09) and GPx (P = 0.05) of the liver, and plasma urea nitrogen (P = 0.06) concentration in the piglet. There was a synergistic role for increasing TDO activity in the liver between dietary tryptophan levels and diquat injection (P < 0.05). These results suggest that increasing dietary tryptophan levels could attenuate the oxidative stress of the liver in weaned piglets intraperitoneally injected with diquat via enhancing the antioxidant capacity.     

The effect of dietary tryptophan levels on oxidative stress of liver induced by diquat in weaned piglets

Oxidative stress can induce abnormal tryptophan metabolism.The present study was mainly conducted to determine the effect of dietary tryptophan levels on oxidative stress in the liver of weaned pigs challenged by diquat.A total of 36 PIC piglets weaned at 21 days of age were randomly allotted to 1 of 3 diets containing dietary tryptophan levels of 0.18,0.30,and 0.45%for 14 d.On day 8,the piglets were injected intraperitoneally with sterile0.9%NaCI solution or diquat(10 mg/kg body weight).During the first 7 d of trial,increasing dietary tryptophan levels enhanced average daily gain(P=0.09) and average daily feed intake(P=0.08),and decreased the feed efficiency(P<0.05) of piglets.The growth performance was decreased by diquat injection(P<0.05).Diquat injection also decreased the activities of the superoxide dismutase(SOD) and glutathione peroxidase(GPx) in the plasma and liver(P<0.05),increased plasma malondialdehyde(MDA)(P<0.05) and urea nitrogen(P<0.05) concentrations,and enhanced MDA concentration(P =0.09) and tryptophan 2,3-dioxygenase(TDO) activity(P =0.07) in liver of piglets.Increasing dietary tryptophan levels could attenuate the effects of diquat injection on the MDA(P =0.06) concentration and the activities of SOD(P=0.09) and GPx(P=0.05) of the liver,and plasma urea nitrogen(P =0.06) concentration in the piglet.There was a synergistic role for increasing TDO activity in the liver between dietary tryptophan levels and diquat injection(P<0.05).These results suggest that increasing dietary tryptophan levels could attenuate the oxidative stress of the liver in weaned piglets intraperitoneally injected with diquat via enhancing the antioxidant capacity.     

Dietary specific antibodies in spray-dried immune plasma prevent enterotoxigenic Escherichia coli F4 (ETEC) post weaning diarrhoea in piglets

In order to establish the mechanism of spray dried plasma powder (SDPP) in improving pig health and performance, a diet containing either 8% SDPP, spray dried immune plasma powder (SDIPP), or control protein (soybean and whey) ration was fed to piglets in an experimental model of enterotoxigenic Escherichia coli F4 (ETEC) post-weaning diarrhoea (PWD). SDIPP was obtained from pigs immunized with a vaccine containing ETEC fimbrial subunit F4 and heat-labile toxin (LT), and SDPP from non-immunized controls. Average daily growth (ADG) was determined, and daily samples of rectal faeces were assessed for diarrhoea (as percentage of dry matter), and ETEC excretion (in CFU/g). SDPP and SDIPP significantly (p<0.05) reduced diarrhoea, and SDIPP significantly reduced ETEC excretion. ADG was not significantly (p>0.05) affected. After the experiment, 30% of piglets tested F4 receptor positive (F4R+). A significant correlation between F4R status and morbidity was found. In F4R+ animals, SDIPP significantly improved diarrhoea and ADG, and decreased ETEC excretion, and SDPP significantly improved diarrhoea and ADG. Surprisingly, SDPP reduced diarrhoea in F4R+ animals without significant reduction of ETEC excretion, which is most likely related to the presence of anti-LT antibodies in SDPP. The results show that oral protection against ETEC by SDPP is attributable to spontaneous antibodies, in this case anti-LT antibodies. Furthermore, the results indicate that the combination of anti-LT and anti-F4 antibodies as in SDIPP is most effective in ETEC prevention. Finally, the F4R distribution in the herd should be taken into account to correctly assess efficacy.     

断奶仔猪肠道微生物氮代谢相关酶活对日粮蛋白水平响应规律

旨在研究断奶仔猪肠道微生物氮代谢相关酶活对日粮粗蛋白(crude protein,CP)水平响应规律。选择54头体质量为(5.55±0.49) kg的28日龄杜洛克×长白×大约克断奶仔猪,采用单因子完全随机设计分配到CP为20%、17%、14%的3组日粮中,每组18个重复,每个重复1头猪。预试期7 d,正试期45 d。分别在正试期10,25及45 d,每组随机挑选6头进行屠宰,采集各肠段食糜和粪便样品分离微生物,测定肠道微生物氮代谢相关酶活力。结果表明,仔猪肠道微生物氮代谢相关酶酶活力具有肠段特异性,日粮高CP水平能显著提高肠道微生物硝酸还原酶(P0.05)、腺苷脱氨酶(P0.05)、谷氨酰胺合成酶(P0.05)、尿素酶(P0.05)、谷丙转氨酶(P0.05)及蛋白酶(P0.05)。肠道微生物的蛋氨酸、组氨酸、赖氨酸、精氨酸、甘氨酸、酪氨酸、色氨酸、谷氨酸脱羧酶活力对日粮高CP水平响应明显(P0.05)。消化道微生物氮代谢相关酶活力对蛋白质水平的响应规律性解析了当前猪蛋白质利用率低的原因。     

Effects of spray-dried porcine plasma and plant extracts on intestinal morphology and on leukocyte cell subsets of weaned pigs

We evaluated the effects of a 6% spray-dried porcine plasma (SDPP) and a plant extracts mixture (XT; 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin) on the productive performance, intestinal morphology, and leukocyte cell subsets of early-weaned pigs compared with a control group. Morphometry of the jejunum, ileum, and colon, and immune cell analysis of blood, ileocolic lymph node (LN), and ileal Peyer's patches were done in 24 weaned pigs (20 +/- 2 d) at 19 or 21 d postweaning. Although SDPP and XT treatments did not increase ADG or ADFI, SDPP improved the G:F ratio (P = 0.024) compared with the control group. Dietary SDPP reduced the percentages of blood monocytes (P = 0.006) and macrophages in ileal Peyer's patches and LN (P = 0.04), of B lymphocytes (P = 0.04) and gammadelta+ T cells in LN (P = 0.009), and of intraepithelial lymphocytes (P = 0.026) as well as the density of lamina propria cells in the colon (P < 0.01). Dietary XT reduced intraepithelial lymphocyte numbers in jejunum (P = 0.034) and the percentages of blood cytotoxic cells (P = 0.07) and B lymphocytes in LN (P = 0.03); however, XT increased blood monocytes (P = 0.038) and the density of lamina propria lymphocytes in the colon (P = 0.003). These results indicate that dietary SDPP and plant extracts can affect intestinal morphology and immune cell subsets of gut tissues and blood in weaned pigs. Furthermore, the effects of SDPP suggest lower activation of the immune system of the piglets.     

日粮添加谷氨酰胺对断奶仔猪小肠形态结构的影响

试验选用60头21d断奶、体重均一的杜长大仔猪。按单因素完全随机化设计随机分为2组,一组为对照组,饲喂基础日粮;一组为试验组,基础日粮添加0.5%的谷氨酰胺,研究谷氨酰胺处理对断奶仔猪小肠黏膜形态变化的影响。在断奶当天及断奶后7d和14d每个处理随机选取3头仔猪屠宰,取小肠组织,测定肠黏膜的形态结构变化。结果表明:日粮中添加谷氨酰胺提高了小肠绒毛高度和固有层厚度及皱褶深度。