Effect of creep feeding on structural and functional changes of the gut of early weaned pigs

Dose-dependent hypersensitivity responses mounted against antigenic constituents of creep feeds have been previously implicated in intestinal damage, digestive disorders and impaired performance of early weaned pigs. In the present study biochemical and histological investigations of the small intestine were undertaken to determine the putative relationship between creep feed level and hypersensitivity response in pigs weaned at 14 days. Creep feed was administered by gastric intubation and weaned pigs received the same diet by gastric intubation for five days. Mucosal structure and function at weaning were not affected by creep feeding regimen. Villus height decreased and crypt depth increased in weaned compared to suckled pigs, but morphology was unaffected by prior exposure to creep. Xylose absorption was not influenced by either creep feed level or weaning. Intraepithelial lymphocyte numbers increased during weaning but were not affected by the creep feeding regimen. Mucosal carbohydrase activity in weaned pigs was not significantly affected by preweaning treatment. The results do not support the hypothesis that post weaning changes in structure and function of the gut are related to creep feed level or to immune responses to dietary antigens.     

Characterization of creep feed consumption and its subsequent effects on immune response, scouring index and performance of weanling pigs

Four trials were conducted to characterize the consumption of creep feed by nursing pigs and the effects of creep feeding (from 10 d to weaning at 28 d) on the immune response, scouring index and subsequent performance of weanling pigs. Pigs were fed a ground 20% CP corn-soybean meal-whey diet with 1.0% chromic oxide (control, 9 litters), this diet with 2.7% ovalbumin added as a dietary antigen (ovalbumin, 14 litters), or no creep feed (unexposed, 11 litters). At weaning, pigs within a litter were fed a 20% CP corn-soybean meal diet either with or without 2.7% ovalbumin. Creep-fed litters began eating at 11 d of age and disappearance of creep feed increased linearly until weaning (P less than .01). However, based on the chronic oxide coloring of the feces, total creep feed consumption was quite variable from pig to pig (13 to 194 g) and from litter to litter (107 to 1,550 g). Preweaning daily gain was similar between creep-fed and noncreep-fed litters; larger litters generally had lower daily gains (P less than .09) and less feed disappearance per pig (P less than .02). Weekly blood sampling showed that pigs fed the antigen diet had a higher (P less than .001) antibody titer to ovalbumin at 14, 21 and 28 d of age than did pigs fed the control diet or pigs unexposed to creep feed. At 56 and 63 d of age, all pigs given an ovalbumin injection at 49 d (1 ml containing 3 mg of ovalbumin) had responded (P less than .001) to injection, with the lowest titers for pigs fed the control creep diet and the highest titers for pigs fed the ovalbumin creep diet; titers were intermediate for pigs not fed creep. Regardless of preweaning or postweaning treatment, most pigs began scouring 4 to 5 d postweaning; scouring peaked at d 10 and returned to normal after d 15. Although the magnitude of difference was small, creep-fed pigs tended to scour more than pigs not fed creep (P less than .01). Postweaning performance was not influenced by preweaning treatments.     

Effects of weaning on diarrhea caused by enterotoxigenic Escherichia coli in three-week-old pigs

We attempted to determine whether weaning is required for induction of diarrhea in pigs with postweaning enterotoxigenic Escherichia coli infection. Three-week-old newly weaned pigs and their suckling littermates were inoculated with the K88+ enterotoxigenic E coli strain M1823B. Fourteen of 21 weaned and 12 of 20 suckling pigs were genetically resistant to intestinal adhesion by the K88+ strain of E coli; they remained healthy, and gained weight at similar rates. Both groups of K88-resistant pigs gained weight faster, and shed fewer bacteria of strain M1823B in their feces, than did their K88-susceptible counterparts. Diarrhea developed in K88-susceptible pigs in the weaned (6 of 7 pigs) and suckling (4 of 8 pigs) groups, and 1 of the 4 affected suckling pigs died from complications resulting from diarrhea. The incidences of diarrhea, weight gain rates, and the numbers of strain M1823B shed in feces of susceptible weaned and suckling pigs were not significantly (P greater than 0.05) different. Diarrhea scores of susceptible weaned pigs were significantly (P less than 0.02) higher than those of susceptible suckling pigs on the second day after inoculation. In this experimental model, it was concluded that weaning is not required for induction of diarrhea, but may modestly increase its severity.     

Pathogenicity of porcine enterotoxigenic Escherichia coli that do not express K88, K99, F41, or 987P adhesins.

Three-week-old weaned and colostrum-deprived neonatal (less than 1 day old) pigs were inoculated to determine the pathogenicity of 2 enterotoxigenic Escherichia coli isolates that do not express K88, K99, F41, or 987P adhesins (strains 2134 and 2171). Strains 2134 and 2171 were isolated from pigs that had diarrhea after weaning attributable to enterotoxigenic E coli infection. We found that both strains of E coli adhered in the ileum and caused diarrhea in pigs of both age groups. In control experiments, adherent bacteria were not seen in the ileum of pigs less than 1 day old or 3 weeks old that were noninoculated or inoculated with a nonpathogenic strain of E coli. These control pigs did not develop diarrhea. Antisera raised against strains 2134 and 2171 and absorbed with the autologous strain, grown at 18 C, were used for bacterial-agglutination and colony-immunoblot assays. Both absorbed antisera reacted with strains 2134 and 2171, but not with strains that express K99, F41, or 987P adhesins. A cross-reaction was observed with 2 wild-type K88 strains, but not with a K12 strain that expresses K88 pili. Indirect immunofluorescence with these absorbed antisera revealed adherent bacteria in frozen sections of ileum from pigs infected with either strain. We concluded that these strains are pathogenic and express a common surface antigen that may be a novel adhesin in E coli strains that cause diarrhea in weaned pigs.     

Effects of preweaning exposure to a starter diet on enterotoxigenic Escherichia coli-induced postweaning diarrhea in swine

Experiments were conducted to evaluate the effect of restricted feeding of a starter diet to suckling pigs (creep feeding) in a model of postweaning colibacillosis. The hypothesis that restricted creep feeding primes an intestinal allergic reaction to starter diet ingested after weaning was tested. Twenty-eight suckling pigs were fed a starter diet for 3 h/d on days 7, 8, and 9 after birth (creep-fed). Twenty-six suckling pigs were not fed the diet until 3 weeks of age (not creep-fed), when all pigs were weaned and given the starter diet. One day after weaning, 24 creep-fed and 22 not creep-fed pigs were inoculated with K88+ enterotoxigenic Escherichia coli, and 4 pigs in each group were kept as noninoculated controls. Among inoculated pigs (principals), 10 creep-fed and 12 not creep-fed pigs were found to be genetically resistant to K88+ E coli and remained healthy during the 6-day postinoculation period, as did the noninoculated controls. Eighteen (10 creep-fed and 8 not creep-fed) of the 24 genetically susceptible principals developed diarrhea after inoculation. There were no significant differences in the incidence and severity of diarrhea, amount of body weight loss, and mortality between creep-fed and not creep-fed susceptible principal pigs. Histologic examination of intestine from control pigs and principals that survived for 6 days after infection did not reveal any substantial morphologic difference between creep-fed and not creep-fed groups. In conclusion, creep feeding was not required for the production of diarrhea in this model. Creep feeding did not induce morphologic changes characteristic of an allergic reaction in the small intestine.     

Response of Gnotobiotic Pigs to Escherichia coli

In a study of the response of gnotobiotic pigs to coliform infections, 45 one-week-old germfree pigs were divided into five groups and each group was inoculated orally with a different strain of Escherichia coli. Three of these were enteropathogenic swine strains, P307[08:K87(B), K88 a,b (L):H19]; P570 [0138:K81]; P568[0141:K85a,b(B), K88a,b(L):H4], one was a virulent human strain, H224, [026:K60(B6)], and one was a non-enteropathogenic swine strain, P581[OX13:K68]. It was attempted to protect a portion of the pigs with orally administered specific antisera and sera from non-immunized specific pathogenfree (SPF) pigs. Observations were made on the clinical response, bacterial counts of feces and intestinal contents, gross pathological changes, distribution of the organisms in organs and serum hemagglutinin titers.

Infection with E. coli P307 resulted in diarrhea, dehydration and death, unless the pig was protected with specific antiserum. The pigs infected with E. coli P570 had a transient diarrhea but retained their appetites and recovered. Those infected with the other three strains remained healthy throughout. No circulating hemagglutinating antibody against the test strains of E. coli could be detected in any of the pigs seven days or earlier post-inoculation.

Relationship could not be established between the numbers of viable E. coli in the feces and the presence of clinical colibacillosis. Orally administered specific antiserum afforded protection against strain P307, but did not reduce the number of E. coli in the gut or alter their distribution in the internal organs. This suggested that the protective effect of specific antibody in the intestine was due to its action on a metabolite (enterotoxin) produced by E. coli P307 rather than the organism itself.

     

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.     

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.     

Postweaning diarrhea in swine: experimental model of enterotoxigenic Escherichia coli infection

A reproducible model of postweaning colibacillosis was obtained by controlling management and environmental variables to simulate conditions often seen at weaning. Suckling pigs were exposed briefly to starter diet at 1 week of age, weaned at 3 weeks of age, held at an ambient temperature of 20 +/- 2 C, and again given the starter diet. One day after weaning, each pig was given 10(10) colony-forming units of enterotoxigenic Escherichia coli strain M1823B (O157:K88ac:H43-LT+ STb+) in broth containing 1.2% sodium bicarbonate via stomach tube. In vitro adhesion by strain M1823B to isolated intestinal branch borders was used to test pigs for susceptibility to K88. In this model, 3 syndromes were induced in susceptible pigs: (1) peracute fatal diarrhea; (2) moderate diarrhea, weight loss, and fecal shedding of the inoculum strain; and (3) no diarrhea, weight loss, and fecal shedding of the inoculum strain. Rotavirus particles were not found in fecal specimens of pigs with diarrhea. The K88-susceptible, noninoculated control pigs remained clinically normal. It was concluded that susceptibility to adhesion by K88+ enterotoxigenic Escherichia coli was a requirement for the production of disease in this model; inoculation with rotavirus was not necessary.     

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.     

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.     

Susceptibility of Chinese Meishan and European large white pigs to enterotoxigenic Escherichia coli strains bearing colonization factor K88, 987P, K99, or F41

Conventionally raised Chinese Meishan and European Large White pigs were intragastrically challenge exposed with 2.1 x 10(10) enterotoxigenic Escherichia coli strains bearing colonization factor K88, 987P, F41, or F41 plus K99. In response to challenge exposure with the K88-positive (K88+) organisms, 96% of Large White pigs died within 48 hours, whereas none of the Meishan pigs died. Both breeds of pigs had similar susceptibility to strains bearing 987P or F41. Lastly, Meishan pigs were found to be more susceptible than Large White pigs to a strain expressing K99 and F41. In pigs with diarrhea, challenge-exposure strains intensively colonized the jejunum (10(8) to 10(10) bacteria/g of tissue) and, to less extent, the duodenum (except K88+ strain, which comprised 10(8)/g). In most cases, jejunal concentrations of the challenge-exposure strains were substantially lower in pigs that did not have diarrhea. Half the resistant Meishan pigs eliminated the K88+ strain from the intestines. Colostral antibody titer that agglutinated challenge-exposure strains did not differ between Meishan and Large White gilts. Results indicate that resistance of pigs to the K88+ strain did not extend to enterotoxigenic strains bearing other well-known factors. They indicate, in addition, that genetic resistance to K88+ strains described in pigs in Europe may exist in pigs in China.     

In vivo transfer of an Escherichia coli enterotoxin plasmid possessing genes for drug resistance.

Experiments were conducted to study transfer of an enterotoxin (Ent) plasmid from a porcine enteropathogenic Escherichia coli to an E coli K12 strain in the intestine of newly weaned pigs. The Ent plasmid carried genes for resistance to tetracycline, streptomycin, and sulfonamides, thereby permitting a selection for tetracycline-resistant exconjugants in the feces of the pigs. In vivo transfer of the Ent plasmid was demonstrated to occur when the pigs were given large oral inocula of donor and recipient cultures, 1 hour apart. Differences in extent of transfer were not detected in pigs given antibiotic-free feed compared with littermates on feed containing oxytetracycline at 50 g/ton. In one experiment, tetracycline-resistant Ent- exconjugants were found which appeared to have received an R plasmid from an enteropathogenic type of E coli resident in the intestine.     

Influence of creep feeding and weaning on brush border enzyme activities in the piglet small intestine

The activities of the enterocyte brush border enzymes lactase (beta-D galactoside galactohydrolase, EC 3.2.1.23) and sucrase (sucrose alpha-D glucohydrolase, EC 3.2.1.48) were measured at set percentage lengths along the small intestines of 112 piglets killed between 21 and 32 days of age. The influences on these activities of consumption of creep feed and of weaning were recorded. Weaning at three weeks old resulted in large, rapid reductions in lactase activity at most sites along the small intestine; sucrase activity declined temporarily and then recovered. Minimum values were recorded about four to five days after weaning. Similar changes were observed whether or not creep feed was consumed before weaning. Continued consumption of creep feed by unweaned pigs over the 21 to 32 day period also produced small but significant reductions in lactase activities. The large loss of digestive enzyme activities at brush borders in weaned animals coincided with a reduced ability to absorb xylose and to checks in growth rate in otherwise healthy piglets.     

Antibacterial activity of antisera against homologous and heterologous Escherichia coli of porcine origin.

Fourteen enteropathogenic and five nonenterotoxigenic Escherichia coli strains isolated from pigs were used for producing antisera in rabbits and pigs. These antisera were used in an vitro test system for antibacterial activity against homologous and heterologous porcine E. coli strains. Antibacterial titres were determined against the homologous strains and the percent reduction in CFU/ml caused by a 1/200 dilution of the sera against heterologous strains was determined. The results indicated that following immunization the antibacterial activity of serum against homologous and heterologous strains was significantly increased. This activity did not appear to be influenced by O and K antigen relationships among the organisms or by enterotoxigenicity of the vaccine strains. When antiserum produced against a combination of three enteropathogenic E. coli was tested against 20 strains a wider spectrum of heterologous antibacterial activity was obtained than with antiserum produced against any individual strain. The results indicate the existence in E. coli strains of porcine origin of common antigenic determinants not related to the serological formula and that a selected combination of strains can be expected to induce antibacterial acitivity against a wide variety of serological types of porcine enteropathogenic E. coli.     

Evaluation of a novel antimicrobial polymer for the control of porcine postweaning colibacillosis

OBJECTIVE: To determine whether CHEMYDERTM polymer has potential for use in the control of porcine postweaning colibacillosis (PWC). PROCEDURE: Two experiments were conducted in which 50 young pigs, either receiving CHEMYDERTM polymer in their food or not, were challenged orally with cultures of beta-haemolytic Escherichia coli immediately after weaning. Their response in terms of development of diarrhoea, and the extent of colonisation of the intestinal tract by the bacteria was monitored. In a third experiment CHEMYDERTM polymer was added to the water supply of a group of 15 pigs on a piggery where PWC was an ongoing clinical problem. The response of these pigs was compared with that of pigs vaccinated against PWC or left unmedicated. RESULTS: In both experimental infection trials the pigs receiving CHEMYDERTM polymer showed significantly reduced intestinal colonisation with the challenge strain of E coli, and, in trial 2, significantly less diarrhoea after weaning compared to pigs not receiving CHEMYDERTM polymer. In the field trial the pigs receiving CHEMYDERTM polymer had significantly less diarrhoea and required significantly less antibiotic treatment than the other two groups of pigs. CONCLUSION: CHEMYDERTM polymer has potential for use in the control of PWC.     

Influence of two supplemental vitamin E levels and weaning age on performance, humoral antibody production and serum cortisol levels of pigs

Three trials using 156 Yorkshire x Hampshire x Duroc crossbred pigs (avg initial wt, 7.9 kg) were conducted to evaluate the effects of two supplemental dietary vitamin E (11 vs 220 IU/kg of diet) and weaning age (21, 28 or 35 d) on performance and immunocompetence of pigs. Supplemental vitamin E (220 IU/kg of diet) increased (P less than .01) serum concentrations of vitamin E for all weaning ages compared with pigs fed 11 IU of vitamin E/kg of diet. However, supplemental vitamin E did not affect performance, serum cortisol concentration or the primary and secondary antibody response to sheep red blood cells. As weaning age increased, weekly ADG and avg daily feed intake increased linearly (P less than .01). Cortisol levels decreased during the 1st wk following weaning and then increased linearly (P less than .01) over time; pigs weaned at 35 d of age had higher (P less than .01) cortisol values initially and over time than pigs weaned at 21 and 28 d. Pigs weaned at 35 d had a higher (P less than .01) primary response to sheep red blood cells than pigs weaned at 21 and 28 d of age, but this effect was not observed for the secondary response. There were no interactive effects (P greater than .10) of dietary vitamin E level and weaning age. In summary, the highest level of supplemental vitamin E increased serum vitamin E concentration but did not affect performance, cortisol levels or one test of the immune response, antibody titers to red blood cells.(ABSTRACT TRUNCATED AT 250 WORDS)     

The effects of creep feed composition and form and nursery diet complexity on small intestinal morphology and jejunal mucosa-specific enzyme activities after weaning in pigs

Fifty-six litters from first-parity sows standardized to 12 piglets were used to determine the effects of creep feed composition and form and the provision of low- or high-complexity nursery diets on the evolution of small intestinal histomorphology and jejunal mucosa-specific enzyme activities postweaning. At 5 d of age, litters (initial bodyweight [BW] 2.31 ± 0.61 kg) were assigned to one of four creep feeding regimens (n = 14): 1) commercial creep feed (COM), 2) liquid milk replacer (LMR), 3) pelleted milk replacer (PMR), or 4) no creep feed (NO). At weaning (21 d of age), six pigs per litter were provided a HIGH- (contained highly digestible animal proteins) or LOW- (contained corn and soybean meal as main protein sources) complexity nursery diet (n = 7). At 21, 28, and 59 d of age, two pigs per pen (one castrated male and one female) were euthanized, and ileal and jejunal segments for histomorphological measurements and jejunal mucosal scrapings were collected to determine specific mucosa enzyme activities. At weaning, pigs provided COM had a greater ileal absorptive capacity (M) than LMR or NO, which were not different (14.1 vs. 10.4 and 10.5 ± 0.9 μm²; P < 0.05); PMR was intermediate. On days 28 and 59, M was not different among pigs regardless of creep feed treatments. Pigs fed LOW had reduced jejunal villus height (VH; P < 0.001) and M (P < 0.001) on day 28 vs. day 21. The VH and M were not different for pigs fed HIGH or LOW by the end of the nursery period. For all dietary treatments except COM-HIGH and COM-LOW, jejunal mucosal maltase-specific activity was not different between days 21 and 28 of age but greater on day 59 (P < 0.05). For pigs that received COM-HIGH, maltase-specific activity was not different between days 21 and 28 but greater on day 59 than day 28 (P < 0.05). For pigs that received COM-LOW, maltase-specific activity was not different between days 21, 28, and 59. Regardless of creep or nursery treatment, sucrase-specific activity was the greatest on day 59, followed by days 21 and 28 (P < 0.001), and lactase-specific activity was greater on day 21 than on days 28 and 59 (P < 0.001), which were not different. Therefore, pigs that provided LOW diet had greater villus atrophy and reduced M during the first week after weaning vs. pigs that provided HIGH, regardless of creep feeding regimen, but were able to recover by the end of the nursery period.     

Postweaning growth check in pigs is markedly reduced by intermittent suckling and extended lactation

The objective of this study was to determine whether intermittent suckling (IS) combined with an extended lactation can reduce postweaning growth check in pigs. Three weaning regimens [conventional weaning (CW), IS with 6-h separation intervals (IS6), and IS with 12-h separation intervals (IS12)] were compared. In CW (n = 17 litters), litters had continuous access to the sow until weaning (d 21, d 0 = farrowing). In IS6 and IS12, litters were separated from the sow for 12 h/d, beginning at d 14 and lasting until weaning (d 41 to 45). Litters were with the sow from 1400 to 2000 and from 0200 to 0800 (IS6, n = 14) or between 2000 and 0800 (IS12, n = 14). Litter size was standardized within 2 d after farrowing by crossfostering, resulting in an average litter size of 10.9 +/- 1.8 piglets. Piglets had ad libitum access to creep feed from d 7 onward. One week after the onset of IS (d 20), creep feed intake was increased in litters from both IS groups compared with CW litters (P < 0.05). Both IS groups consumed considerable amounts of creep feed before weaning (d 41 to 45). Total feed intake before weaning was greater (P = 0.004) in IS12 (3,808 +/- 469 g/piglet) than in IS6 (2,717 +/- 404 g/piglet). In comparison, CW litters consumed 18 +/- 9 g/piglet before weaning (d 21). Irrespective of weaning regimen, total feed intake of litters before weaning was highly correlated with post-weaning feed intake (P < 0.001). Furthermore, in all treatment groups, total preweaning feed intake was correlated with postweaning growth (P < 0.10). Irrespective of treatment, piglets suckling anterior teats grew faster than piglets suckling middle or posterior teats during the first 2 wk of lactation. Body weights at the end of the experiment (d 55) were similar among weaning regimens. Onset of IS induced a growth check in both IS groups (34% for IS12 and 22% for IS6). Only a mild growth check was observed after weaning of IS litters (14% for both IS groups). However, a serious growth check (98%) was observed after weaning of CW litters. Results of the current study indicate that IS stimulated feed intake during lactation, providing a more gradual transition to weaning. Because the IS6 regimen did not prevent the growth check after the onset of IS and is rather laborious, we suggest that IS12 might be preferable for a practical implementation of IS.     

A tryptophan-enriched diet improves feed intake and growth performance of susceptible weanling pigs orally challenged with Escherichia coli K88

We tested the effect of Trp addition to a standard weaning diet and oral challenge with enterotoxigenic Escherichia coli K88 (ETEC) on growth and health of piglets susceptible or nonsusceptible to the intestinal adhesion of ETEC. Sixty-four pigs weaned at 21 d of age were divided into 3 groups based on their ancestry and BW: a control group of 8 pigs fed a basal diet (B), the first challenged group of 28 pigs fed B diet (BCh), and the second challenged group of 28 pigs fed a diet with Trp (TrpCh). The Trp diet was produced by the addition of 1 g of l-Trp/kg to the basal diet. On d 5, pigs were orally challenged with 1.5 mL suspension containing 10(10) cfu ETEC/mL or placebo, and killed on d 9 or 23. Based on in vitro villus adhesion assay, the pigs (except the B group) were classified as susceptible (s(+)) or nonsusceptible (s(-)) to the intestinal ETEC adhesion. Thus, after the challenge, treatments were B, BChs(-), BChs(+), TrpChs(-), and TrpChs(+). Pigs susceptible to ETEC were 50.0% in the BChs(+) group (3 pigs lost included) and 46.4% in the TrpChs (+) group (1 pig lost included). During the first 4 d after challenge, the challenge reduced ADG (P < 0.05), and this reduction was greater in susceptible pigs (P < 0.05) than nonsusceptible ones. Tryptophan increased ADG and feed intake in susceptible pigs (P < 0.05) from challenge to d 4, but not thereafter. Tryptophan supplementation did not improve the fecal consistency and did not reduce the number of pigs positive for ETEC in feces on d 4 after the challenge. The K88-specific immunoglobulin A activity in blood serum tended to be greater in challenged pigs (P = 0.102) and was not affected by the addition of Trp. Villous height was affected by the addition of Trp and challenge in different ways, depending on the site of small intestine. The need to consider the phenotype for the adhesion of the ETEC in studies with different supply of Trp was clearly evident. When compared with practical weaning standard diets, Trp supplementation allowed susceptible pigs to partially compensate for the effects of ETEC challenge by increasing feed intake and maintaining an adequate BW growth. This is of practical importance for the formulation of diets for pigs selected for lean growth because of the presence of an association between this trait and the susceptibility to the intestinal adhesion of ETEC.