Coliform numbers in the stomach and small intestine of healthy pigs following weaning at three weeks of age

Impact of dietary Chlorella vulgaris and feed enzymes on health status, immune response and liver metabolites in weaned piglets

In this study, we analysed the impact of dietary inclusion of Chlorella vulgaris and carbohydrases on general health, redox status, immune response, liver lipids and metabolites in weaned piglets. Forty-four male piglets were allocated into four diets: control (n = 11), CH (control diet with 5% CH, n = 10), CH+R (control diet with 5% CH plus 0.005% Rovabio Excel AP, n = 10), and CH+M (control diet with 5% CH plus 0.01% of a pre-selected four-CAZyme mixture, n = 11). After 15 days of trial, animals were slaughtered and samples of blood and liver collected. Spectrophotometry methods and commercial kits were used to determine blood parameters and gas and liquid chromatography for hepatic fatty acid and chlorophylls profiles, respectively. While total, LDL- and VLDL-cholesterol were increased by CH, the opposite was recorded for HDL-cholesterol (p < 0.001). Piglets fed CH-based diets presented an increase of IgG and a decrease of IgM (p < 0.001) which along with lymphocytes exacerbation contributed for piglets' survival after weaning. n-6 PUFA were reduced in piglets fed CH and the opposite occurred for n-3 PUFA (p < 0.001), thus benefiting n-6/n-3 ratio in the liver. Chlorophylls amount was not changed by the use of Rovabio or enzymatic mixture. The discriminant analysis applied to hepatic parameters revealed a clear separation between control and CH-based diets but failed to discriminate feed enzymes. Our findings indicate health promoting effects of CH as feed ingredient in piglets' nutrition at weaning, without negatively impacting on animals' performance.

Analysis of temporal fecal microbiota dynamics in weaner pigs with and without exposure to enterotoxigenic Escherichia coli1,2

The primary aim of this work was to study potential effects of subclinical enterotoxigenic Escherichia coli (ETEC) exposure on porcine fecal microbiota composition, with a secondary aim of profiling temporal shifts in bacterial communities over the weaning transition period. 16S rRNA gene metabarcoding and quantitative PCR (qPCR) were used to profile the fecal microbiota and quantify ETEC excretion in the feces, respectively. Temporal shifts in fecal microbiota structure and stability were observed across the immediate postweaning period (P < 0.05), including significant shifts in the relative levels of specific bacterial phylotypes (P < 0.05). ETEC exposure did not change the fecal microbiota structure (P > 0.05), but significant variations in fecal community structure and stability were linked to variations in ETEC excretion level at particular time points (P < 0.05). In this study, marked temporal changes in microbiota structure and stability were evident over the short weaning transition period, with a relationship between ETEC excretion level and fecal microbiota composition being observed. This study has provided a detailed analysis of fecal microbiota dynamics in the pig, which should help to inform the development of novel management strategies for enteric disorders based on an improved understanding of microbial populations during the challenging postweaning period.

Effects of dietary supplementation of Acanthopanax senticosus on gastrointestinal tract development in calves

Twenty-four newborn Holstein dairy male calves (with initial body weight of 38 ± 3.0 kg) were used in a randomized block design experiment to determine effects of dietary supplementation of Acanthopanax senticosus (AS) on gastrointestinal tract development. Calves were fed milk (10%/body weight) three times at 06.00, 12.00 and 18.00 hours daily with one to four treatments during the experimental periods (4 to 28 days): no supplementation of AS (control group, CG); 1.0 g/L•time of micro-powder AS (MP); 1.0 g/L•time of superfine powder AS (SP); or 1.0 g/L•time of coarse powder AS (CP). On days 7, 14, 21 and 28, 20 mL blood samples were collected at 06.00 hours before the morning feeding. At the end of the trial (28 days), all calves were euthanized, and tissue samples were taken and placed in 4% buffered formaldehyde for analyses. In the rumen of MP treatment, compared with the CG treatment, wall thickness and papillae diameter was both significantly lower (P<0.05), while crypt depth was significantly greater (P<0.05). In the duodenum, villi diameter of AS supplemented treatments was significantly lower than that of CG treatment (P<0.05). Results indicate that calves during sucking period supplemented with AS as MP style could promote gastrointestinal development.

A feed additive containing Bacillus toyonensis (Toyocerin(®) ) protects against enteric pathogens in postweaning piglets

AIMS

This study evaluated the efficacy of a probiotic containing Bacillus toyonensis spores (Toyocerin(®) ) in postweaning piglets against enteric pathogens.

METHODS AND RESULTS

Seven hundred and ninety-two healthy weaning pigs of a commercial farrow-to-finish pig farm were used. The negative control group fed without Toyocerin(®) and two experimental groups fed similar to the negative control group, but supplemented with Toyocerin(®) at t 500 mg kg(-1) diet (Toyocerin 500 group) and 1000 mg kg(-1) diet (Toyocerin 1000 group), respectively. No significant difference (P > 0.05) in morbidity and mortality rate between groups was noticed. The Toyocerin groups showed higher body weight (P < 0.05) and lower feed conversion ratio compared to the negative control group. Diarrhoea score was less in both Toyocerin groups than negative control group (P < 0.05). Moreover, the use of Toyocerin(®) at 1000 mg kg(-1) diet resulted in higher average daily feed intake compared to other groups (P < 0.05), reduction of some enteric pathogens and increase of the number of lactic acid bacteria.

CONCLUSIONS

The use of Toyocerin(®) in weaning pigs, especially at 1000 mg kg(-1) diet, improved their health and growth performance.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study shows that a feed additive containing B. toyonensis (Toyocerin(®) ) protects against enteric pathogens in postweaning piglets when fed this additive at a proper dose. The use of Toyocerin(®) at 1000 mg kg(-1) diet resulted in higher average daily feed intake, decrease of some enteric pathogens and higher number of lactic acid bacteria. The effect of the probiotic in other age groups remains to be established.

Nutritional influences on some major enteric bacterial diseases of pig

There are several enteric bacterial diseases and conditions of pigs that require control to prevent overt disease, to reduce morbidity and mortality, and to improve the efficiency of production. Traditionally, veterinarians, feed manufacturers and producers have relied upon antibiotics and minerals (for example, ZnO, CuSO4) in diets for a large part of this control. However, recent trends, particularly in Europe, are to reduce antimicrobial use and seek alternative or replacement strategies for controlling enteric bacterial diseases. The majority of these strategies rely on 'nutrition', taken in its broadest sense, to reduce the susceptibility of pigs to these diseases. Evidence to date suggests that specific dietary interventions, for example feeding very highly-digestible diets based on cooked white rice, can reduce the proliferation of a number of specific enteric bacterial infections, such as post-weaning colibacillosis. No simple and universal way to reduce susceptibility to pathogens in the gastrointestinal tract has been identified, and the underlying basis for many of the reported positive effects of 'nutrition' on controlling enteric infections lacks robust, scientific understanding. This makes it difficult to recommend dietary guidelines to prevent or reduce enteric bacterial diseases. Furthermore, some diseases, such as porcine intestinal spirochaetosis caused by Brachyspira pilosicoli, are sometimes associated with other pathogens (co-infections). In such cases, each pathogen might have different nutrient requirements, ecological niches and patterns of metabolism for which a variety of dietary interventions are needed to ameliorate the disease. Greater understanding of how 'nutrition' influences gut epithelial biology and immunobiology, and their interactions with both commensal and pathogenic bacteria, holds promise as a means of tackling enteric disease without antimicrobial agents. In addition, it is important to consider the overall system (i.e. management, housing, welfare) of pig production in the context of controlling enteric bacterial diseases.

Effects of chito-oligosaccharide supplementation on the growth performance, nutrient digestibility, intestinal morphology, and fecal shedding of Escherichia coli and Lactobacillus in weaning pigs

A total of 50 weaning pigs (16 d of age; 4.72 +/- 0.23 kg of BW) were selected to investigate the effect of dietary chito-oligosaccharide (COS) supplementation on growth performance, fecal shedding of Escherichia coli and Lactobacillus, apparent digestibility, and small intestinal morphology. Pigs housed in individual metabolic cages were assigned randomly to 5 treatments (n = 10), including 1 basal diet (control), 3 diets with COS supplementation (100, 200, and 400 mg/kg), and 1 diet with chlortetracycline (CTC) supplementation (80 mg/kg). Fresh fecal samples were collected to evaluate shedding of E. coli and Lactobacillus on d 0, 7, 14, and 21 postweaning. Fresh fecal samples collected from each cage from d 19 to 21 were stored frozen for determination of apparent total tract digestibility. On d 21, all pigs were killed to collect the middle sections of the duodenum, jejunum, and ileum for determination of mucosa morphology. Supplementation of COS at 100 and 200 mg/kg and supplementation of CTC improved (P < 0.05) overall ADG, ADFI, and G:F in comparison with the control. Supplementation of COS at 200 mg/kg as well as supplementation of CTC increased (P < 0.05) apparent total tract digestibility of DM, GE, CP, crude fat, Ca, and P, whereas COS at 100 mg/kg increased (P < 0.05) the digestibility of DM, Ca, and P in comparison with the control diet. Pigs receiving diets supplemented with COS or CTC had a decreased (P < 0.05) incidence of diarrhea and decreased diarrhea scores compared with control pigs. Fecal samples from pigs receiving diets supplemented with COS had greater (P < 0.05) Lactobacillus counts than those from control pigs and pigs receiving diets supplemented with CTC on d 14 and 21. However, supplementation of COS at 200 mg/kg and supplementation of CTC decreased (P < 0.05) E. coli counts in the feces on d 21 compared with the control diet. Dietary supplementation of COS at 200 mg/kg and of CTC increased (P < 0.05) the villus height and villus:crypt ratio at the ileum and jejunum, and COS at 100 mg/kg also increased (P < 0.05) the villus height in the ileum compared with the control diet. The current results indicated that dietary supplementation of COS at 100 and 200 mg/kg enhanced growth performance by increasing apparent digestibility, decreasing the incidence of diarrhea, and improving small intestinal morphology.

Classification of temporal profiles of F4+ E. coli shedding and faecal dry matter in experimental post-weaning diarrhoea of pigs

Enterotoxigenic F4+ Escherichia coli can colonize the intestine of pigs and cause diarrhoea. Our primary goal was to find a discriminant rule to discriminate between F4+ E. coli shedding profiles as this may reflect differences in the infectiousness of pigs. Our secondary goal was to find a discriminant rule to discriminate between diarrhoeic and non-diarrhoeic pigs. Repeated measurements (bacterial shedding and percentage dry matter of faeces) were taken of 74 weaned pigs that were infected experimentally with F4+ E. coli. These measurements were summarized into two new variables by means of a principal components analysis. Discriminant rules were derived based on these summary variables by fitting a mixture of normal distributions. Finally, the association between the classifications (as derived from the discriminant rules) and the occurrence in the pigs of the F4 receptor, an adhesion site for F4+ E. coli, was studied. We found that only the classification based on bacterial shedding allowed us to distinguish two significantly different groups of pigs (high and low shedders). Presence of the F4 receptor was associated strongly with pigs being high shedders.

The influence of different management systems and age on intestinal morphology, immune cell numbers and mucin production from goblet cells in post-weaning pigs

At time of weaning, the immune system in piglets is not fully mature resulting in reduced growth and increased mortality. Early-weaned pigs transported to a segregated early weaning (SEW) facility have enhanced performance and gut development compared to conventional (CONV) pigs which may be due, in part, to decreased pathogen challenge. To gain further insight into SEW enhanced performance and gut development, gut samples from pigs weaned at 19+/-2 days were assessed during the post-weaning (PW) period. The numbers of cells expressing CD2, CD4, CD8, and CD172 (the 74-22-15 (SWC3) antibody is now known to be specific for CD172), MHC class II, and CD25 were quantified using immunohistochemistry. Additionally, samples of duodenum, jejunum, and ileum were evaluated for the production of neutral, acidic, and sulfuric mucins from goblet cells and morphological measurements were also made. No effects due to the management systems alone were observed for any of the parameters. However, there were interactive effects of age/time post-weaning and management system on the immune cells as well as on the mucin secreting goblet cells. There were no differences in gut morphology between SEW and CONV reared pigs.

Preventive effects of the probiotic Escherichia coli strain Nissle 1917 on acute secretory diarrhea in a pig model of intestinal infection

Pretreatment with the probiotic Escherichia colistrain Nissle 1917 (EcN) was assessed in a pig model of intestinal infection to prevent acute secretory diarrhea. In the model 10(10) colony forming units of the porcine enterotoxigenic Escherichia coli Abbotstown (EcA) was given via orogastric tube to weaned piglets at day 21 postpartum (-EcN/+EcA group, n = 7). Forty-eight hours after challenge electrophysiological parameters of isolated intact jejunal epithelia were characterized in Ussing chambers. In agreement with clinical signs of diarrhea, tissues of challenged animals showed an overshoot of secretory response after stimulation of the cAMP-mediated second messenger pathway by forskolin, indicating higher excitability of chloride secretory systems under infected conditions. The data were compared with respective measurements from animals that got a daily dose of 10(10) cfu of the probiotic EcN over 10 days before EcA challenge (+EcN/+EcA group; n = 4), from a group that received only EcN (+EcN/-EcA; n = 4), or from a group that remained totally untreated (-EcN/-EcA; n = 6). EcN pretreatment completely abolished clinical signs of secretory diarrhea in +EcN/+EcA animals. Furthermore, jejunum epithelia of these animals did not exhibit an overshoot of secretory response upon stimulation with forskolin. Our studies demonstrate for the first time the efficacy of prophylactic EcN in pig small intestine for preventing an effect of toxigenic EcA. This infection model with freshly weaned piglets may be predestinated to further characterize EcN effects on the cellular level, i.e., involved second messenger pathways, or it may also be useful to examine the efficacy of other substrates or microbe strains against secretory stimuli.

Development of Post-weaning Diarrhoea in Piglets. Relation to Presence of Escherichia coli Strains and Rotavirus

Weaning of piglets complicated with an exposure to pathogenic strains of Escherichia coli was scrutinized in two sets. The first set comprised 20 animals representing two litters and the second set included 30 animals from five litters. The piglets were either left as controls or exposed to one or three pathogenic strains of E. coli. Aiming to simulate a natural exposure the challenge strains were spread on the floor of the pens at weaning. In addition the pigs experienced several non-infectious stress factors commonly occurring at that occasion. Some groups were given adrenocorticotropic hormone (ACTH), aiming to simulate a stressful weaning. The balance and the composition of the faecal coliform populations, measured by a metabolic fingerprinting method, was disturbed among all animals following weaning. This disturbance was more pronounced and lasted longer among piglets exposed to pathogenic strains of E. coli. All piglets exposed to pathogenic E. coli shed these strains in faeces. Diarrhoea was induced in the groups exposed to E. coli, but not among the control animals. Pigs not treated with ACTH and subjected to a single pathogenic strain of E. coli became infected but did not develop diarrhoea unless if coinciding with shed of rotavirus. Control pigs excreting rotavirus had no diarrhoea. Diarrhoea was most frequent in the groups exposed to three pathogenic strains of E. coli, and in these groups diarrhoea was seen in the absence of rotavirus. ACTH administration amplified the clinical signs. The litter of origin influenced the development of post-weaning diarrhoea.

Effect of weaning on small intestinal structure and function in the piglet

Fifty-four piglets were selected from 12 litters weaned at 17 (Treatment 1), 21 (Treatment 2), 28 (Treatment 3) and 35 (Treatment 4) days old, respectively, to determine the effect of weaning age on small intestinal villus morphology, immunology and histochemistry. From proximal duodenum, proximal jejunum, distal jejunum and middle ileum, intestinal samples with three replicates (piglets) in each treatment were taken at 18, 22, 28 and 36; 22, 28, 36 and 43; 28, 36, 43, and 50; and 18, 22, 28, 36, 43 and 50 d of age in Treatment 1, 2, 3 and 4, respectively. This was equivalent to 12 h, 3 d, 1 week, 2 week postweaning in Treatment 1; 12 h, 1 week, 2 week, 3 week postweaning in Treatment 2 and 3, and all the same age in Treatment 4 as in Treatment 1, 2, 3, respectively. The results showed that villous height of duodenum and proximal jejunum decreased significantly in Treatment 1 and 3. Crypt depth in the duodenum, proximal jejunum and ileum also decreased significantly in Treatment 1. Date had significant effect on villous height of the duodenum, distal jejunum and ileum with the shortest on day 29 and crypt depth of all positions increased with piglet age except the crypt depth in proximal jejunum decreased on day 50. Weaning age and day of age had significant effects on intraepithelial lymphocyte (IEL) number and goblet cell (GC) number at all positions of small intestinal mucosa in piglets. The number of IEL at all segments of small intestinal mucosa in Treatment 3 increased significantly compared to those in other treatments, but IEL number at all locations of small intestinal mucosa in Treatment 2 decreased significantly compared to those in other treatments. The number of GC in small intestinal mucosa increased significantly in early-weaned (< day 21) piglets. It appears that providing fluid milk replacer for a few days postweaning could dramatically reduce the negative impact of weaning on villous morphology and digestive and absorptive function, especially in pigs weaned prior to 3 week of age. Finally, as weaning age was reduced, GC had a greater role in intestinal duct protection.

Aspects on feed related prophylactic measures aiming to prevent post weaning diarrhoea in pigs

The ability of feed related measures to prevent or reduce post weaning diarrhoea (PWD) was examined in a split litter study including 30 pigs from 6 litters allotted into 5 groups. Four groups were exposed to 3 pathogenic strains of E. coli via the environment at weaning. Three of them were given zinc oxide, lactose+fibres or non-pathogenic strains of E. coil as probiotics. The challenged and the unchallenged control groups were given a standard creep feed. Diarrhoea was observed in all challenged groups but not among uninfected animals, and the incidence of diarrhoea was lower in the group given nonpathogenic E. coli compared to all other challenged groups. The severity of PWD also differed between litters. When corrected for mortality due to PWD, a decreased incidence of diarrhoea was also seen in the groups given zinc oxide or lactose+fibres. The dominating serotype of E. coil within faecal samples varied from day to day, also among diarrhoeic pigs, indicating that diarrhoea was not induced by one single serotype alone. The diversity of the faecal coliform populations decreased in all piglets during the first week post weaning, coinciding with an increased similarity between these populations among pigs in the challenged groups. This indicated an influence of the challenge strains, which ceased during the second week. The group given lactose+fibres was least affected with respect to these parameters. In conclusion feed related measures may alleviate symptoms of PWD.

Effect of supplementary feeding during the sucking period on net absorption from the small intestine of weaned pigs

An intestinal perfusion technique was used to measure the effects of supplementary feeding (experiment 1) and temporary weaning (experiment 2) during the sucking period on the net absorption of fluid, sodium, chloride and potassium from the small intestine of pigs after weaning. The technique was also applied to control pigs which did not receive supplementary feed and were not temporarily weaned during the sucking period. Paired intestinal segments were prepared at five sites along the small intestine in each of 80 pigs in experiment 1 and 36 pigs in experiment 2. The cranial segment of each pair was infected with enterotoxigenic Escherichia coli (ETEC). In both experiments, four days after weaning, the net absorption of fluid, sodium and chloride in the uninfected segments was in general significantly less in all the pigs than at weaning or seven, 11 and 14 days after weaning and it was significantly greater in the pigs given supplementary feed than in the other pigs. Net absorption values in the infected segments of the control pigs were less four days after weaning than on the day of weaning. No differences were found between pigs that were temporarily weaned or not and those that were not fed during the sucking period. Supplementary feeding during the sucking period partially prevented the decrease of net absorption usually observed after weaning in uninfected and in ETEC-infected segments of intestine.

Effects of weaning and enterotoxigenic Escherichia coli on net absorption in the small intestine of pigs

The purpose of this study was to measure the net absorption of fluid, sodium, potassium and chloride in the small intestine of weaned pigs and of their unweaned littermates and to correlate these values with villus height and crypt depth. Five pairs of segments of the small intestine were prepared in each of 80 pigs; the cranial segment of each pair was injected with an enterotoxigenic strain of Escherichia coli and the caudal segment with a control solution. Net absorption was measured on the day of weaning and four, seven, 11 and 14 days after weaning. In unweaned pigs the net absorption of fluid, potassium and chloride did not vary with time. In weaned pigs the net absorption of fluid in the control segments was significantly less on days 4, 7 and 14 after weaning and of sodium and chloride on days 4 and 7 than in unweaned littermates. In infected segments of weaned pigs the net absorption of fluid was significantly less than in unweaned littermates on day 11 and 14, of sodium and potassium on day 11 and of chloride on days 4 and 11 after weaning. Net absorption was negatively correlated with villus height but only in the infected segments of weaned pigs; no other correlations were found. It was concluded that after weaning the net absorption of fluid and electrolytes in the small intestine of pigs is temporarily decreased, a condition that may initiate diarrhoea.

Villus height and crypt depth in weaned and unweaned pigs, reared under various circumstances in The Netherlands

The height of the villi and depth of the crypts in the small intestine were studied after weaning in pigs reared under various circumstances in the Netherlands. Pigs taken from herds with a long history of postweaning diarrhoea had in general significantly shorter villi and deeper crypts than their counterparts from a specific pathogen-free herd. Weaning was associated with villus shortening, crypt deepening and subsequent villus lengthening in pigs from the specific pathogen-free herd. Giving supplementary feed during the sucking period was beneficial in preventing shortening of the villi and this villus shortening was less severe when the crypts were deep at weaning, a condition that perhaps lessens the severity of postweaning diarrhoea.

Clinical and microbiological field studies in The Netherlands of diarrhoea in pigs at weaning

A longitudinal study investigated the clinical signs and aspects of the aetiology of diarrhoea in pigs at weaning. Two litters of pigs were randomly selected from each of four Dutch herds with a history of diarrhoea after weaning. The pigs were inspected and faecal samples were collected daily. Before weaning, enterotoxigenic Escherichia coli was isolated from only two pigs but after weaning from all the pigs. Before and after weaning, rotaviruses were detected in almost all the pigs during one to four episodes. Rotavirus or enterotoxigenic E coli were generally detected when the pigs had diarrhoea; however, they were also encountered in normal faeces. In many faecal samples from pigs with diarrhoea no pathogenic agent was detected. In almost all the pigs after weaning, E coli types appeared and predominated transiently before they were superseded by another type. This study confirms the results of others in showing that rotaviruses and E coli are important in the aetiology of diarrhoea in pigs at weaning. However, diarrhoea after weaning is probably not caused by these two agents alone; other factors also probably contribute to the syndrome.

Plasma level of antisecretory factor (ASF) and its relation to post-weaning diarrhoea in piglets

Antisecretory factor (ASF) is a regulatory peptide which counteracts diarrhoea in the pig; ASF is rapidly absorbed from the pig intestine, and significantly reduces the incidence of neonatal diarrhoea in the suckling offspring. ASF is synthesized in the central nervous system, and released to the blood stream via the pituitary gland. In two different experiments (n = 8 and n = 4), the blood concentration of ASF was followed in 5-weeks old piglets from day 7 before weaning up to day 12 days after weaning. In both experiments ASF concentrations were significantly (p < 0.01) lower on day three post-weaning, than either before weaning or on days 7 and 12 post-weaning. In another experiment, where plasma ASF activity was determined in relation to clinical signs of diarrhoea seven days post-weaning, it was found to be 0.87 +/- 0.08 units/ml (mean +/- SEM) in healthy weaners (n = 15), but only 0.22 +/- 0.05 units/ml in piglets suffering from diarrhoea (n = 15), the difference being significant. The faecal flora both of healthy weaners and of their matched controls suffering from diarrhoea were subjected to bacteriological examination before and after weaning, and found to be similar in both groups, namely a mixture of aerobic and anaerobic Gram negative rods, Campylobacter jejuni, Staphylococcus aureus/epidermidis, and Enterococcus faecalis. No particular pathogen was predominant in any of the diseased animals.

A comparison of the ecology of Escherichia coli in the intestine of healthy unweaned pigs and pigs after weaning

A total of 51 clinically healthy pigs (14 unweaned and 37 weaned) from five litters, and aged 21 to 35 d, were studied. Escherichia coli isolates from the duodenum, jejunum, ileum, caecum and colon were differentiated on the basis of O-serogroup, biotype and resistance pattern. The complexity of the flora was influenced considerably by the presence or absence of the enterotoxigenic serotype 0149: K91, K88a,c (Abbotstown strain). When it was absent the E. coli flora of both weaned and unweaned pigs was complex with up to 25 strains being identified. The majority of these E. coli strains identified in each pig were isolated from only one of the five intestinal sites sampled. On the other hand, when the enterotoxigenic strain was present (14 pigs) it tended to dominate the E. coli flora at all levels of the intestine and this dominance was reflected in a corresponding fall in the total number of E. coli strains isolated per pig.