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.     

A prolonged photoperiod improves feed intake and energy metabolism of weanling pigs

In a 2-wk experiment, the effect of photoperiod on performance and energy metabolism of newly weaned pigs was studied. Forty 4-wk-old crossbred weanling barrows weighing 8.0 kg (SE = 0.13) were assigned to one of eight groups (five pigs per group) based on BW and litter. Groups were allotted to one of two lighting schedules: 8 h light:16 h darkness or 23 h light:1 h darkness. Each group was housed in a climate respiration chamber. Piglets had ad libitum access to feed and water. Energy and nitrogen balances, heat production, ADFI, and ADG were measured weekly. Heat production, energy metabolism, and performance were unaffected (P > 0.10) by photoperiod during wk 1. However, in the 2nd wk ADFI (418 vs 302 g/d) and ADG (381 vs 240 g/d) were higher (P < 0.05 and P = 0.05, respectively) for pigs on the 23:1 h lighting schedule than for those on the 8:16 h schedule. Furthermore, heat production (P < 0.10), total energy retention, and energy retained as protein and as fat were higher (P < 0.05) during wk 2 in pigs on the 23:1 h lighting schedule (8, 125, 41, and 350%, respectively) than in those on the 8:16 h schedule. Moreover, metabolizability of energy tended to be higher (P < 0.10) and energy requirements for maintenance were lower (P < 0.05) during wk 2 for pigs on the 23:1 h schedule compared with those on the 8:16 h schedule (P < 0.10). In conclusion, exposing pigs to a longer period of light after weaning stimulated ADFI and ADG. In addition to the feed intake, the high ADG is due to an improved metabolizability of energy and a reduced energy requirement for maintenance. This study suggests that lighting schedule can be used as a tool to stimulate feed intake after weaning.     

Dietary supplementation with cellooligosaccharide improves growth performance in weanling pigs

Nondigestible oligosaccharides are not digested in the small intestine, but are fermented by bacteria colonizing in the large intestine. Physiological effects of non‐digestible oligosaccharides have been considered to be conferred by the fermentation of bacteria colonizing in the large intestine. Because cellooligosaccharide is a non‐digestible oligosaccharide, various physiological effects are expected. However, physiological functions of cellooligosaccharide are not well understood. This experiment was conducted to clarify the effect of dietary supplementation with cellooligosaccharide on the growth performance in weanling pigs. The result showed that average daily gain was significantly higher (P < 0.05) in pigs fed a diet supplemented with cellooligosaccharide than in pigs without cellooligosaccharide. There was a tendency to increasing average daily feed intake in pigs with cellooligosaccharide, though the significant difference was not detected (P = 0.18). Feed efficiency and nutrient digestibility of feces and ileum were not changed by feeding cellooligosaccharide. In addition, blood urea nitrogen was significantly higher (P < 0.05) in pigs fed the diet supplemented with cellooligosaccharide than in pigs without cellooligosaccharide. The concentrations of acetic and iso‐valeric acids in the cecum of pigs fed the diet with cellooligosaccharide tended to be higher (P < 0.10) than those without cellooligosaccharide. The results obtained in this study demonstrated that dietary supplementation with cellooligosaccharide improves growth performance in weanling pigs.     

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.     

Response to an Escherichia coli K88 oral challenge and productivity of weanling pigs receiving a dietary nucleotides supplement

Background:Dietary nucleotides,considered as antibiotics alternative,were shown to have positive effects on intestinal hyperaemia,systemic immunity,small-intestinal growth,and hepatic composition in pigs.However,there is no previous research on nucleotide supplementation in weanling pigs under an oral challenged E.coli K88.Therefore,2 experiments were conducted to investigate the effects of dietary nucleotides on weanling pig growth performance,nutrient digestibility,fecal score,and blood profile after being orally challenged with E.coli K88.Methods:In Exp.1,a total of 140 weanling pigs[8.33 ± 0.33 kg of body weight(BW),28-d old]were used in this42-d feeding trial.Pigs were distributed into 1 of 4 treatments,5 pigs/pen(3 barrows and 2 gilts) and 7 pens/treatment.Treatments were a control basal diet(CON) or the CON supplemented with 150(R150),220(R220),or 275(R275) mg/kg to give the three treatment diets.In Exp.2,28 weanling pigs(BW = 8.40 ± 0.22 kg,28-d old) were distributed into 1 of 4treatments to give 1 pig/pen and 7 pens/treatment in a 42-d feeding and challenge trial.Dietary treatments were the same as in Exp.1.On d 14,all those pigs(BW= 13.3 ±0.15 kg,42-d old) were orally dosed with 1.5 mL suspension containing 10~(10) cfu/mL of E.coli K88.Twenty four hours after challenge,blood and excreta samples were collected from each pigs for analysis.Fecal scores were measured on d 7,14,21,and 28 of the study.Results:In Exp.1,overall BW,average daily gain(ADG),gain/feed(G/F) ratio,and nutrient digestibilities were lower(P 0.05) in CON group compared with the nucleotides fed pigs.In Exp.2,after challenge,IgA,IgM,and IGF-I were higher(P 0.05) in the nucleotide groups compared with CON.However,the nucleotide groups had lower(P 0.05) Cortisol and TNF-α compared with CON.Fecal E.coli counts and fecal score for the nucleotide groups were lower(P 0.05) than for CON.Conclusions:In conclusion,dietary nucleotides supplementation could improve growth performance,nutrient digestibility,immune status,microbial balance,reduce diarrhea,and provide protection against enterotoxigenic E.coli K88 infection in weanling pigs.     

Effect of fishmeal replacement with spray-dried animal plasma and colistin on intestinal structure,intestinal microbiology,and performance of weanling pigs challenged with Escherichia coli K99

We evaluated spray-dried animal plasma (SDAP) as an alternative to antimicrobial medication with colistin sulfate in weanling pigs challenged with Escherichia coli K99. Forty-eight piglets weaned at 24 d of age were distributed into 12 pens, and each pen was assigned to one of four dietary treatments. All the piglets were given an oral dose of 5 x 10(7) cfu of E. coli K99 at weaning. The dietary treatments followed a factorial arrangement with two levels of SDAP (0 and 7%) and two levels of colistin (0 and 300 mg/kg of diet). The ADG and ADFI were measured on d 7 and 14 of trial. Three piglets from each treatment were killed on d 7 and 14 to remove the small intestine, and to obtain ileal and cecal digestive contents. The inclusion of SDAP improved ADG by 68 g (P < 0.05) and ADFI by 41 g (P < 0.10) in wk 1 of trial. During wk 2, SDAP improved ADG by 41 g (P < 0.10) and gain:feed ratio (G:F) by 25% (P < 0.01). On the other hand, whereas colistin had no effect on performance in wk 1, it improved ADG by 102 g (P < 0.01), ADFI by 62 g (P < 0.01), and G:F by 26% (P < 0.01) in wk 2. Over the 14 d of the trial, ADG was improved by 54 (P < 0.05) and 75 g (P < 0.05), and G:F was improved by 35 (P < 0.05) and 32% (P < 0.05) due to SDAP and colistin, respectively. There was interaction between colistin and SDAP for ADFI in wk 2 and between d 0 to 14 (P < 0.05), which indicates that their effects were not additive. The use of colistin was advantageous in the maintenance of the integrity of the intestinal mucosa of the pigs, as suggested by a small intestine that was 93 g heavier (P < 0.10) and with the tallest villi 106 microm longer (P < 0.10) than in pigs without colistin. The inclusion of SDAP in the diet favored the growth of lactobacilli in the ileum (P < 0.10) and the cecum (P < 0.05), whereas colistin reduced the number of enterococci in the cecum (P < 0.05) and of Escherichia coli both in the ileum and the cecum (P < 0.001). These results suggest that SDAP may be an alternative to medicated feed with antibiotics since it provided a level of protection against an experimental challenge with E. coli K99 similar to that obtained with colistin, an antibiotic of proven efficacy. The current situation in which the use of antimicrobials in animal feeding is being questioned should encourage further investigation into the use of SDAP as a means of preventing disease in pigs at weaning.     

Effects of sweeteners on individual feed intake characteristics and performance in group-housed weanling pigs

To assess the effects of 2 high intensity sodium saccharine-based sweeteners on individual feed intake characteristics and performance of group-housed weaned pigs, one hundred ninety-eight 26-d-old weanling pigs were given ad libitum access to 3 dietary treatments containing: no additional sweetener (control), 150 mg of sweetener (Sucram C-150)/kg, or 150 mg of sweetener (Sucram 3D)/kg. At weaning, piglets were allocated to 18 pens (11 pigs/pen) based on BW, sex, and ancestry, and pens were randomly assigned to 3 treatments with 6 pens per treatment. The pens were equipped with computerized feeding stations. During the first 12 d, pigs were offered pelleted prestarter diets that were replaced at once by pelleted starter diets for the last 7 d of the 19-d experimental period. The individual feed intake characteristics consisting of latency time (interval between weaning and first feed intake), initial feed intake (intake during the first 24 h following the first feed intake), the number of total visits per day, and the number of visits in which feed was consumed, together with the time and the feed intake per visit, were determined for all piglets. Performance traits and fecal consistency were determined per pen for d 0 to 5, d 5 to 12, and d 12 to 19, as well as for the total period (d 0 to 19). The initiation of feed intake was not affected by the addition of high intensity sweeteners to the diet. From 12 d postweaning, dietary sweeteners caused the piglets to focus more on feed intake and less on exploratory behavior, as shown by the increased percentage of visits with feed intake in pigs fed the Sucram 3D diet compared with those fed the control diet (P = 0.002). The overall daily feed intake increased with time but was not affected by the addition of sweeteners. Nevertheless, dietary sweeteners prevented the depression of feed intake on d 8 and 10 postweaning (d 8, P = 0.013; d 10, P = 0.014), which seemed to coincide with an improved fecal consistency score (d 5 to 12, P = 0.11; d 12 to 19, P < 0.001). However, the changes in feed intake characteristics and fecal consistency only resulted in numerical effects on postweaning pig performance (ADFI, P = 0.126; ADG, P = 0.140). The results of the present study indicate that weanling pigs need a certain period of time before clear effects of dietary sweeteners on individual feed intake characteristics and pig performance can be observed.     

Escherichia coli diarrhoea in pigs with or without the K88 receptor.

There was a high incidence of neonatal scours in 38 litters of pigs born at Compton in a four month period during 1978. The most important cause of the disease was an enteropathogenic Escherichia coli strain which possessed the K88 antigen. The Compton herd has been bred to produce pigs of three genotypes with respect to the presence or absence of the intestinal receptor for the K88 antigen. These are homozygous dominants (SS) and heterozygotes (Ss) susceptible to infection by virulent K88-positive E coli, and homozygous recessives (ss) resistant to the disease. The highest incidence of diarrhoea was in the susceptible progeny of resistant dams and susceptible sires. There was no K88 associated diarrhoea in resistant progeny or in susceptible progeny of susceptible dams.     

Effect of added dietary threonine on growth performance,health, immunity and gastrointestinal function of weaning pigs with differing genetic susceptibility to Escherichia coli infection and challenged with E. coli K88ac

Threonine (Thr) is important for mucin and immunoglobulin production. We studied the effect of added dietary Thr on growth performance, health, immunity and gastrointestinal function of weaning pigs with differing genetic susceptibility to E. coli K88ac (ETEC) infection and challenged with ETEC. Forty‐eight 24‐day‐old weaned pigs were divided into two groups by their ETEC susceptibility using mucin 4 (MUC4) gene as a marker (2 MUC4^?/?, not‐susceptible, and 2 MUC4^+/+, susceptible, pigs per litter). Within genotype, pigs were fed two different diets: 8.5 (LThr) or 9.0 (HThr) g Thr/kg. Pigs were orally challenged on day 7 after weaning and slaughtered on day 12 or 13 after weaning. Before ETEC challenge, HThr pigs ate more (p < 0.05). The diet did not affect post‐challenge growth, but HThr tended to increase post‐challenge feed efficiency (p = 0.087) and overall growth (p = 0.087) and feed efficiency (p = 0.055). Before challenge, HThr pigs excreted less E. coli (p < 0.05), while after challenge, diet did not affect the number of days with diarrhoea and ETEC excretion. MUC4^+/+ pigs responded to the challenge with more diarrhoea, ETEC excretion and anti‐K88 IgA in blood and jejunal secretion (p < 0.001). HThr pigs had a higher increase of anti‐K88 IgA values in jejunal secretion (p = 0.089) and in blood (p = 0.089, in MUC4^+/+ pigs only). Thr did not affect total IgA and IgM values, morphometry of jejunum, goblet cells count in colon, total mucin from jejunum and colon, but varied jejunal goblet cells counts (p < 0.05). In the first two post‐weaning weeks, 8.5 g Thr/kg diet may be not sufficient to optimize initial feed intake, overall feed efficiency and intestinal IgA secretion and to control the gut microbiota in the first post‐weaning week, irrespective of the pig genetic susceptibility to ETEC infection.     

Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance,immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide

Background: This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter(AGP) on performance, immune status and gut structure after an E. coli lipopolysaccharide(LPS) challenge. Thirty-six pigs were allotted to six treatments including: a non-challenged control(NCC); LPS-challenged control(CC); CC + AGP; CC + yeast extract; CC + enzymes; and CC + enzymes + yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal samples.Results: Overall(d 1 to 11), compared with CC pigs, AGP attenuated the LPS-induced reduction in ADG(P = 0.004),ADFI(P = 0.03) and gain/feed ratio(P = 0.01). At 6 h post-challenge, AGP pigs had lower plasma urea N(PUN; P = 0.02)and serum TNF-α concentration(P = 0.07), and higher platelet count(P = 0.04) and serum IL-10 concentration(P = 0.02) than CC pigs. At 48 h post-challenge, AGP pigs had lower PUN(P = 0.02) than CC pigs, whereas enzymes + yeast extract interacted non-additively(P = 0.001) to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN(P = 0.02)and higher duodenal(P = 0.03), jejunal(P = 0.01) and ileal(P = 0.07) villus height than CC pigs. In addition, enzymes +yeast extract interacted additively and non-additively to reduce ileal IFN-γ(P 0.0001) and IL-10(P = 0.012) expression,respectively. Generally, no differences(P 0.10) were observed between AGP and enzymes + yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ(P 0.0001) and TNF-α(P = 0.003) in enzymes + yeast extract pigs at 96 h post-challenge.Conclusions: The LPS challenged piglets receiving enzymes + yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance.     

Effects of casein glycomacropeptide supplementation on growth performance,intestinal morphology,intestinal barrier permeability and inflammatory responses in Escherichia coli K88 challenged piglets

Casein glycomacropeptide(CGMP) is a bioactive peptide derived from milk with multiple functions. This study was aimed at evaluating the effects of CGMP as a potential feed additive on growth performance,intestinal morphology, intestinal barrier permeability and inflammatory responses of Escherichia coli K88(E. coli K88) challenged piglets. Eighteen weaning piglets were randomly assigned to three groups.Control group and K88 challenged group received a basal diet, and CGMP treated group received the basal diet supplemented with 1% of CGMP powder. The trail lasted for 12 days, K88 was orally administered to the piglets of K88 challenged group and CGMP treated group on days 8-10. The results showed that the diet containing 1% CGMP significantly alleviated the decrease in average daily gain(P 0.05),increase in pathogenic bacteria amounts in intestinal contents(P 0.05), intestinal morphology(P 0.05) and barrier permeability damage(P 0.05), and acute inflammatory response(P 0.05)induced by E. coli K88 infection. In conclusion, CGMP supplementation in the diet protected the weaning piglets against E. coli K88 infection.     

Effects of a Quillaja saponaria extract on growth performance and immune function of weanling pigs challenged with Salmonella typhimurium

Ninety-six pigs (initially 8.9 kg and 24 d of age) were used in a 28-d experiment to determine the effects of Quillaja saponaria extract (QS) on weanling pig growth performance and immune function in response to enteric disease challenge with Salmonella typhimurium (ST). Experimental treatments were arranged in a 2 x 4 factorial with main effects of disease challenge (control vs ST-challenge) and dietary addition of QS (0, 125, 250, or 500 mg/kg). Pigs were fed QS diets for 14 d and then challenged orally with ST or sterile media. There were no differences in ADG or ADFI among dietary treatments, but gain/feed ratio (G/ F) was depressed (P < 0.06) in pigs fed 250 mg/kg QS. ST-challenge reduced ADG (P < 0.05), ADFI (P < 0.05), and G/F (P < 0.05) 1 wk after challenge. Daily estimates revealed reductions in feed intake in ST-infected pigs on d 2 to 5 following infection (P < 0.05), and rectal temperature was increased maximally 2 d following infection (P < 0.05). There was a marked decline in serum IGF-I during the 6 d after ST-infection (P < 0.05). ST-challenge produced a rise (P < 0.05) in serum haptoglobin on d 7 after challenge, and serum alpha1-acid glycoprotein (AGP) in ST-challenged pigs also was elevated (P < 0.05) above controls on d 7 and 14 after challenge. Serum immunoglobulin (Ig) M increased (P < 0.05) over time in both groups, and serum IgM of ST-challenged pigs was greater than controls on d 7 after challenge (P < 0.05). Serum IgG was not affected by enteric disease challenge; however, on d 7 and 14 after disease challenge, serum IgG for both groups was greater (P < 0.05) than on d 0. Dietary QS had no significant influence on any of the end points used to characterize the acute phase response to ST-challenge. Phagocytic cell function was depressed in pigs fed 250 (P < 0.05) and 500 (P < 0.05) mg/kg as compared to pigs fed 125 mg/kg QS. Yet, there was no difference in phagocytic function among pigs fed 0, 250, or 500 mg/kg QS. We conclude that this model of enteric disease invokes an acute phase response accompanied by decreases in feed intake and serum IGF-I. Furthermore, dietary QS, at the levels fed in this study, appears to offer little benefit to growth performance or immune function in the presence or absence of ST-challenge.     

Escherichia coli K88 receptor expression in intestine of disease-susceptible weaned pigs.

A challenge trial was carried out in which Escherichia coli O157 K88ac was administered to a litter of weaned pigs and the development of the disease monitored over a five-day experimental period. The eight animals in the trial were assigned to two groups depending on whether they exhibited disease symptoms. Six pigs developed diarrhoea and two appeared unaffected; these were designated as the test (or K88-susceptible) group and the control (or K88-resistant) group, respectively. The animals were euthanised and the intestine was removed and sections processed for brush border membrane vesicle preparation. Microscopic and biochemical assays were undertaken on tissue samples from each animal and a strong correlation was observed between the expression of a glycoprotein receptor complex associated with the brush border membrane and the development of disease symptoms. Further investigation revealed the presence of an analogous glycoprotein complex in the K88-resistant group which did not bind the K88-fimbriae antigen. These results suggest that genetic differences in the glycosyl moieties of the receptor complex provide the basis for disease susceptibility to K88-positive E. coli.     

Escherichia coli phytase improves growth performance of starter, grower, and finisher pigs fed phosphorus-deficient diets

Corn-soybean meal-based diets, consisting of a high-P control (HPC) containing supplemental dicalcium phosphate (DCP), a basal diet containing no DCP, and the basal diet plus Escherichia coli phytase at 500 or 1,000 phytase units per kilogram (FTU/kg; as-fed basis) were fed to evaluate growth performance in starter, grower, and finisher pigs. Pigs were blocked by weight and gender, such that average weight across treatments was similar, with equal numbers of barrows and gilts receiving each treatment in each block. In Exp. 1, 48 pigs with an average initial BW of 11 kg, housed individually, with 12 pens per diet, were used to evaluate growth performance over 3 wk. Overall ADG and G:F were increased linearly (P < 0.05) by dietary phytase addition. Final BW and plasma P concentrations at 3 wk also increased linearly (P < 0.05). In Exp. 2, 128 pigs with an average initial BW of 23 kg, housed four pigs per pen, with eight pens per diet, were used to evaluate growth performance over 6 wk. A linear increase in response to phytase was noted for ADG and G:F in all three 2-wk periods, as well as overall (P < 0.05). Percentage of bone ash also showed a linear increase (P < 0.01). In Exp. 3, 160 pigs (53 kg), housed five pigs per pen, with eight pens per diet, were used to evaluate growth performance over 6 wk. A linear increase was detected for final BW, as well as ADG and G:F in the first and second 2-wk periods, and overall (P < 0.01). Twenty-four 15-kg individually housed pigs were used to evaluate total-tract nutrient digestibility in Exp. 4. Daily absorption of P linearly increased (P < 0.05) with phytase supplementation. Results of this research indicate that E. coli phytase is effective in liberating phytate P for uptake and utilization by starter, grower, and finisher pigs.     

Dose-response investigation of oral ketoprofen in pigs challenged with Escherichia coli endotoxin

In order to determine the effective dose, the effects of orally administered ketoprofen were evaluated in pigs following intravenous challenge with Escherichia coli endotoxin. One hour after the challenge, five groups of pigs were treated with either tap water or ketoprofen (0.5 mg/kg, 1 mg/kg, 2 mg/kg or 4 mg/kg). The body temperature was measured and a total clinical score was calculated after assessing the general behaviour, respiratory rate and locomotion of the pigs. Thromboxane B(2) and ketoprofen concentrations were analysed from blood samples. Ketoprofen treatment significantly reduced the rectal temperature and total clinical scores, and lowered blood thromboxane B(2) concentrations when compared with the control group. Ketoprofen plasma concentrations were lower than previously reported in healthy pigs after similar doses. The appropriate dose of orally administered ketoprofen in pigs in this model is 2 mg/kg, as the higher dose of 4 mg/kg failed to provide an additional benefit.     

Inhibition of adhesion of Escherichia coli K88 antigen by mammary secretions of susceptible and resistant sows

Anti-adhesive activities of colostrum and milk from genetically susceptible sows, which protected their susceptible offspring in an outbreak of neonatal diarrhoea caused by K88-positive Escherichia coli, were compared with the activities in mammary secretions of resistant dams that did not protect their susceptible progeny. There was significantly more anti-adhesive antibody in the secretions of susceptible sows than in resistant sows, both during the disease period, and 1 year later. Fractionation of colostrum by gel filtration and ion-exchange chromatography led to identification of the anti-adhesive antibodies as including both IgA and IgM.     

Effects of beta-glucan extracted from Saccharomyces cerevisiae on growth performance, and immunological and somatotropic responses of pigs challenged with Escherichia coli lipopolysaccharide

Three experiments were conducted to investigate the effects of beta-glucan supplementation on pig performance and immune function. In Exp. 1, 100 weaned pigs (8.65 +/- 0.42 kg of BW and 28 +/- 2 d of age) were used in a 35-d experiment to determine the effects of graded levels of beta-glucan. Pigs were randomly allotted to 1 of 5 treatments containing beta-glucan supplemented at 0, 25, 50, 100, or 200 ppm. Each treatment was replicated using 5 pens containing 4 pigs per pen. The ADG of pigs between d 14 to 28 and d 0 to 28 responded to dietary beta-glucan in a quadratic fashion (P < 0.05), whereas beta-glucan had no effect on ADFI and G:F in any period. In Exp. 2, 80 crossbred pigs (8.23 +/- 0.56 kg of BW and 28 +/- 2 d of age) were used in a 35-d experiment. Pigs were allotted to 1 of 2 dietary treatments (0 or 50 ppm of beta-glucan in the diet) using 10 pens with 4 pigs per pen. Pigs treated with beta-glucan had greater ADG in the 14- to 28-d (P = 0.05) and 0-to 28-d (P = 0.035) periods. The ADFI of pigs receiving beta-glucan was increased (P < 0.05) in the periods from 0 to 14, 0 to 28, and 28 to 35 d. The lymphocyte proliferation index in response to phytohemagglutinin (P = 0.051) and concanavalin A (P = 0.052) tended to decrease on d 14 in pigs supplemented with beta-glucan compared with pigs without supplementation. In Exp. 3, 24 barrows (8.89 +/- 0.20 kg of BW and 28 d of age) were used to investigate the immunological and somatotropic responses of pigs challenged with lipopolysaccharide (LPS). Experimental treatments were arranged in a 2 x 2 factorial, with the main effects of LPS challenge (saline vs. LPS) and dietary addition of beta-glucan (0 vs. 50 ppm). Pigs were raised individually in metabolic cages. Pigs were fed 0 or 50 ppm of beta-glucan for 28 d and then challenged with LPS (25 microg/kg of BW) or saline. After LPS injection, blood was obtained at 0, 1.5, 3, 4.5, 6, and 7.5 h to determine cytokine production and the somatotropic response. Dietary beta-glucan increased plasma interleukin-6 at 1.5, 3, and 4.5 h and tumor necrosis factor-alpha at 3 and 4.5 h and increased plasma interleukin-10 from 3 to 7.5 h after LPS challenge. The beta-glucan treatments had no effect on growth hormone. In conclusion, beta-glucan can selectively influence performance and partially offer benefits on somatotropic axis and immune function in weaned piglets challenged with LPS.     

Growth performance and gut health of Escherichia coli–challenged weaned pigs fed canola meal-containing diet

An experiment was conducted to evaluate the effects of including canola meal (CM) in diets for weaning pigs challenged with a F18 strain of Escherichia coli on growth performance and gut health. A total of 36 individually housed weaned pigs (initial body weight [BW] = 6.22 kg) were randomly allotted to one of the three diets (12 pigs/diet). The three diets were corn–soybean meal (SBM)-based basal diet (control diet) and the basal diet with 0.3% zinc oxide, 0.2% chlortetracycline, and 0.2% tiamulin (antibiotic diet) or with 20% CM diet. The diets were fed in two phases: Phase 1: days 0 to 7 and Phase 2: days 7 to 20. All pigs were given an oral dose of 2 × 10⁹ CFU of F18 strain of E. coli on day 7. Fecal score was assessed daily throughout the trial. Dietary antibiotics increased (P < 0.05) overall average daily gain (ADG) and average daily feed intake (ADFI) compared by 48% and 47%, respectively. Dietary CM increased (P < 0.05) overall ADG and ADFI by 22% and 23%, respectively; but the ADG and ADFI values for CM-containing diet did not reach those for the antibiotics-containing diet. Dietary antibiotics reduced (P < 0.05) fecal score; however, dietary CM unaffected fecal score. Dietary antibiotics decreased (P < 0.05) liver weight per unit live BW by 16% at day 20, whereas dietary CM did not affect liver weight per unit live BW (29.2 vs. 28.6). Also, dietary antibiotics increased (P < 0.05) serum triiodothyronine and tetraiodothyronine levels for day 14, whereas dietary CM did not affect the serum level of these hormones. Dietary antibiotics reduced (P < 0.05) the number white blood cells and neutrophils by 38% and 43% at day 20, respectively, whereas dietary CM tended to reduce (P = 0.09) the number white blood cells by 19% at day 20. The number white blood cells for CM diet tended to be greater (P < 0.10) than that for antibiotics diet. The dietary antibiotics decreased (P < 0.05) the concentration of individual volatile fatty acids and hence of total volatile fatty acid in cecum by 61% at day 20, whereas dietary CM decreased (P < 0.05) cecal butyric acid concentration by 61% and tended to reduce (P < 0.10) total volatile fatty acid concentration by 30% at day 20. In conclusion, the dietary inclusion of 20% CM improved ADG and tended to reduce white blood cell counts. Thus, inclusion of CM in antibiotics-free corn-SBM-based diets for weaned pigs that are challenged with F18 strain of E. coli can result in their improved performance partly through a reduction of the inflammatory response.     

Effect of glutamine and spray-dried plasma on growth performance, small intestinal morphology, and immune responses of Escherichia coli K88+-challenged weaned pigs

Forty weaned barrows (5.32 +/- 0.3 kg BW) at 17 +/- 2 d of age were used to investigate the effects of feeding glutamine and spray-dried plasma on the growth performance, small intestinal morphology, and immune responses of Escherichia coli K88-challenged pigs. Pigs were allotted to four treatments including: 1) nonchallenged control (NONC); 2) challenged control (CHAC); 3) 7% (as-fed basis) spray-dried plasma (SDP); and 4) 2% (as-fed basis) glutamine (GLN). On d 11 after weaning, all pigs were fitted with an indwelling jugular catheter. On d 12 after weaning, pigs in the CHAC, SDP, and GLN groups were orally challenged with skim milk E. coli K88 culture, whereas pigs in the NONC group were orally inoculated with sterilized skim milk. Rectal temperatures and fecal diarrheic scores were recorded and blood samples collected at 0 (baseline), 6, 12, 24, 36, and 48 h after the challenge for serum hormone and cytokine measurements. At 48 h postchallenge, all pigs were killed for evaluation of small intestinal morphology. There was no effect of feeding SDP or GLN on growth performance during the 11-d prechallenge period (P = 0.13). At 48 h after the challenge, CHAC pigs had decreased ADG (P = 0.08) and G:F (P = 0.07) compared with the NONC pigs; however, SDP and NONC pigs did not differ in G:F, and GLN and NONC pigs did not differ for ADG and G:F. At 6, 36, and 48 h after the challenge, CHAC, SDP, and GLN pigs had increased rectal temperature relative to the baseline (P = 0.09). At 12 and 36 h after the challenge, CHAC pigs had the highest incidence of diarrhea among treatments (P = 0.08). Serum IL-6 and ACTH were not affected by treatment or time after E. coli challenge (P = 0.11). In proximal, midjejunum, and ileum, CHAC pigs had greater villous atrophy and intestinal morphology disruption than NONC pigs (P < 0.01), whereas SDP and GLN pigs had mitigated villous atrophy and intestinal morphology impairment after E. coli challenge. Pigs in the SDP had the lowest GH at 12 h and the greatest GH at 36 h after the challenge among treatments (P = 0.08). Pigs in the NONC had the highest IGF-1 at 12 and 36 h postchallenge (P < 0.04). These results indicate that feeding glutamine has beneficial effects in alleviating growth depression of E. coli K88-challenged pigs, mainly via maintaining intestinal morphology and function, and/or possibly via modulating the somatotrophic axis.     

抗大肠杆菌K88卵黄粉对断奶仔猪生长和腹泻的影响

采用单因子随机化设计,将60头健康断奶仔猪按体重和性别一致的原则分成3个组,每组4个重复,每个重复5头猪。各组仔猪分别采食3种试验日粮(基础日粮;基础日粮+卵黄粉0.1%;基础日粮+卵黄粉0.3%)。结果表明,添加含抗大肠杆菌K88的卵黄粉可显著提高断奶仔猪的生产性能,其中断奶后前2周的平均日增重分别比对照组提高了11.34%和1.03%,饲料报酬分别改善4.65%和7.44%。添加卵黄粉也显著降低断奶仔猪采食量,添加0.1%卵黄粉增加仔猪采食量6.35%,0.3%的卵黄粉则使采食量降低6.35%。结果还显示,使用含抗大肠杆菌抗体K88的卵黄粉添加剂显著降低了腹泻率,改善断奶仔猪健康状况。