Prevalence and pathogenicity of Cryptosporidium suis in pre- and post-weaned pigs

A total of 4338 faecal samples, 135 of sows, 3368 of pre-weaned and 835 of post-weaned piglets from eight farms in South Bohemia, Czech Republic were collected and examined for Cryptosporidium infection. No sow, but 5.7% pre-weaned and 24.1% post-weaned piglets were positive for Cryptosporidium infection. No relationship was found between diarrhoea and Cryptosporidium infection in any of the different age groups (pre- and post-weaned piglets). Four piglets, which were sporadically shedding cryptosporidia in faeces, were necropsied. Neither clinical signs of diarrhoea nor macroscopical changes were found. Histologically, a moderate infection of cryptosporidia was detected in the glandular epithelium along the large intestine, with predisposition to the ansa centralis of the colon. No inflammatory response in the lamina propria was observed. Cryptosporidia were also commonly found in the glandular epithelium of submucosal lymphoglandular complexes in the colon. Cryptosporidium isolates from all farms were identified as Cryptosporidium suis using molecular markers (SSU rRNA). All of the C. suis strains obtained were larger [6.2 (6.0-6.8) x 5.5 (5.3-5.7) microm] than any isolate described so far [4.6 (4.4-4.9) x 4.2 (4.0-4.3) microm] and did not appear to be infective for neonatal BALB/c mice.     

Anti‐microbial Susceptibility for east1+Escherichia coli Isolated from Diarrheic Pigs in Korea

The in vitro susceptibilities of 128 isolates of east1⁺Escherichia coli from pre‐weaned and post‐weaned pigs with diarrhoea were tested with nine commonly used anti‐microbial agents by an agar dilution minimal inhibitory concentration (MIC) procedure according to National Committee for Clinical Laboratory Standards guidelines. For the isolates from pre‐weaned and post‐weaned pigs, most of them were susceptible to low concentrations (MIC₉₀) of tetracycline (4 and 2 μg/ml), ceftiofur (2 and 2 μg/ml), and colistin (4 and 2 μg/ml). Marked resistance was found in others.     

Prevalence and age-related infection of Cryptosporidium suis, C. muris and Cryptosporidium pig genotype II in pigs on a farm complex in the Czech Republic

A total of 413 pig faecal samples were collected from pre-weaners (119), starters (131), pre-growers (123) and sows (40) from a farm with a closed breeding system segmented into two breeding complexes and a growing complex in the region of Vysočina, Czech Republic and screened for the presence of Cryptosporidium using staining methods and genotyping (SSU rRNA). Cryptosporidium oocysts were detected by microscopy in the faeces of 21.1% of the samples (87/413). Sequence analyses and RFLP identified C. suis in 44, Cryptosporidium pig genotype II in 23 and C. muris in 2 samples. No mixed infections were found.Pigs under 7 weeks of age were infected with C. suis only. Cryptosporidium pig genotype II was found in animals from 7 weeks of age. No relationship was found between diarrhoea and any Cryptosporidium infection in any of the different age groups (P < 0.05). The pre-weaned pigs shed significantly more Cryptosporidium oocysts than older pigs and it was associated with C. suis infection.     

Occurrence of reproductive disorders in pig herds with and without Chlamydia suis infection – statistical analysis of breeding parameters

Chlamydiae are frequently encountered Gram‐negative intracellular eubacteria that can cause clear manifestations or clinically asymptomatic disorders. C. suis and other chlamydia are primarily isolated in cases of reproductive disorders. This study was performed to estimate the impact of Chlamydia suis infection on reproduction in sows by analyzing reproduction rates and breeding parameters. The test was conducted on first generation (F1) pigs from Polish Landrace (PL) × Polish Large White (PLW). Sixty‐four herds were investigated and 500 vaginal swabs were collected. Isolation of DNA was carried out directly from the swabs. All samples were analyzed for Chlamydia suis by real‐time PCR with a locked nucleic acid (LNA)‐containing probe. To analyze the impact of chlamydia infection on reproductive parameters, evaluation questionnaires were used. Reproductive problems were found in 77.3% of the farms tested. The receiver operating characteristic curve indicated that in the farms with 10 up to 120 sows, there were higher reproductive problems with chlamydia infection than in smaller and bigger pig farms. The most common problems were estrus repetition, which was reported by 57.81% of the surveyed farms, and the birth of dead piglets, which was reported by 31.25% of the investigated pig farms. Abortions, which were reported by 28.12% of the surveyed farms, were the least common reproductive disorders.     

Effects of temperature and temperature‐humidity index on the reproductive performance of sows during summer months under a temperate climate

Heat stress is known to influence sow reproduction, but it is unknown to which extent under temperate climates. Therefore, the impact of temperature and temperature‐humidity index (THI) on the reproductive performance of sows during summer months from 2009 to 2011 were studied. Reproductive parameters of 22 264 inseminations and 21 610 resulting farrowings of 22 German commercial farms were analyzed. Climatic records were available from the nearest weather station. Effects of temperature and THI at different periods of the reproductive cycle were estimated from May to September where temperatures were expected to influence climatic conditions indoors. High temperatures and THI values 5 days pre‐ and 14 days post‐breeding reduced litter size by 0.01 to 0.03 piglets (P < 0.05). Prior to farrowing, the number of liveborn piglets was reduced (P < 0.05) and of stillborns increased with rising climatic variables (P < 0.001). On the day of farrowing, reduced numbers of weaned piglets were observed when temperature and THI values were elevated (P < 0.05), but pre‐weaning mortality was not influenced (P > 0.05). In conclusion, even under temperate conditions adverse effects of climatic variables on the reproductive performance of sows are present. Thereby, the number of liveborn piglets can be considered as the most sensitive parameter to heat stress. Considering the impact of climate change and predicted heat waves, strategies to mitigate the impact of heat stress are necessary.     

仔猪球虫病及其防控措施

仔猪球虫病是困扰猪场的主要疾病之一，病原是猪等孢球虫。该病在临床上主要引起1~3周龄仔猪腹泻，造成仔猪生长速度缓慢，断奶体重明显降低。单纯的球虫感染引发的死亡率虽然不高，但遇到产房里其他疾病混合感染时可能出现死亡率的大幅度上升。猪等孢球虫在全世界的猪场感染率都很高，影响了猪场经济效益，但由于死亡率不高往往容易被猪场忽视，特别是在隐性感染症状不明显的猪场。文章回顾了等孢球虫的生活史、国内外的流行病学、检测方法以及控制方案，希望能为广大养猪从业者控制仔猪球虫病提供一个清晰的思路。     

Ecological Dynamics of Campylobacter in Integrated Mixed Crop–Livestock Farms and Its Prevalence and Survival Ability in Post‐Harvest Products

This study investigated the ecological distribution of zoonotic bacterial pathogen, Campylobacter, in mixed crop–livestock (MCL) farms compared to conventional farms and their products at pre‐ and post‐harvest levels. A total of 222 Campylobacter isolates were identified. At pre‐harvest level, a total of 1287 samples from seven MCL farms, four conventional poultry farms, four organic produce‐only and five conventional produce‐only farms from Maryland and the DC metropolitan area were analysed from 2012 to 2014. Campylobacter was detected in 11.16% and 3.6% of MCL and conventional farm samples, respectively, but none from produce‐only farm samples. Tetracycline resistance was observed in 51.02% of MCL farm isolates but none among conventional farm isolates. For post‐harvest analysis, a total of 1281 food products from seven farmers markets, three organic retail supermarkets and three conventional retail supermarkets were collected from the same area. Campylobacter was isolated in 87.5%, 71.43% and 33.33% of whole chicken carcasses in farmers markets, organic and conventional retail supermarkets, respectively. No Campylobacter was detected in post‐harvest produce samples due in part to the inability of Campylobacter to survive in absence of sufficient water activity. Overall, this study reveals public health concerns regarding the MCL farm environment and their products that are sold in retail and farmers markets.     

Genotypic Prevalence of the Adhesin Involved in Diffuse Adherence in Escherichia coli Isolates in Pre‐weaned Pigs with Diarrhoea in Korea

A total of 1002 Escherichia coli strains isolated from pre‐weaned pigs with diarrhoea on 1114 swine farms were screened for the presence of the adhesin involved in diffuse adherence (AIDA) gene by polymerase chain reaction (PCR). Escherichia coli isolates that carried AIDA genes were also tested by PCR for the detection of five fimbriae (F4, F5, F6, F18 and F41), heat‐stable (STa, STb) and heat‐labile (LT) enterotoxin, enteroaggregative E. coli heat‐stable enterotoxin 1 (EAST1), and Shiga toxin 2 oedema disease (Stx2e) genes. Twenty‐three (2.3%) of the 1002 E. coli isolates carried the gene for AIDA. Among 23 isolates shown to carry genes for AIDA, three carried the AIDA gene as the only shown virulence factor. Other isolates carried other virulence factor genes in addition to AIDA. Four isolates carried genes for at least one of the fimbrial adhesins and enterotoxins. Sixteen isolates carried genes for enterotoxins only. The AIDA may represent an additional virulence determinant in pre‐weaned pigs with diarrhoea.     

The prevalence of isospora suis and strongyloides ransomi in suckling piglets in the Netherlands

Summary

Faecal samples from suckling piglets from 113 litters on 25 farms in the Netherlands were examined to study the prevalence of gastrointestinal parasites, in particular Strongyloides ransomi and Isospora suis. S. ransomi was not found but I. suis was demonstrated in 17 of the 25 farms and in 41 out of 77 litters of these farms (53%). No other parasites were found. On the basis of these results, a longitudinal study on the incidence and significance of I. suis was performed on 10 farms (5 litters/farm). I. suis was found on 9 out of 10 farms and in 56% of the litters. Farms differed in infection levels, measured as the numbers of patent litters, and in the onset of patency. Other parasites were only found in faecal samples from the sows and from farrowing pens. These were, in order of prevalence, Balantidium coli, Ascaris suum, Eimeria spinosa, E. debliecki and E. suis.     

Pathogenesis of intestinal cryptosporidiosis in conventional and gnotobiotic piglets.

The pathogenesis of intestinal cryptosporidiosis was studied in 52 conventionally reared and 20 gnotobiotically reared piglets by inoculation with different doses of Cryptosporidium parvum oocysts. The prepatent period of C. parvum in both groups of animals were variable, depending on the number of oocysts administered. The patent period of C. parvum in conventionally reared piglets was 8 or 9 days; in gnotobiotic piglets cryptosporidia were found in feces until Day post infection (DPI) 16, when the last piglet was necropsied. Cryptosporidiosis in conventionally reared piglets is a self-limited diarrheal disease associated with morphological changes within the intestine. The most severe lesion was seen in the posterior jejunum and ileum from DPI 3 to DPI 7, and consisted of villous atrophy, crypt hyperplasia and inflammatory infiltration in the lamina propria. In gnotobiotic piglets cryptosporidia induced severe enterocolitis which occurred at least until DPI 16. The characteristics of enteric lesions were similar to those found in conventionally reared piglets. Intestinal cryptosporidiosis in both groups of animals shifted in the course of infection in the caudal direction and terminated in the large intestine. Examination by scanning electron microscope showed that infected absorptive cells had thicker and longer microvilli than those on non-infected cells; neighboring non-infected cells were hypertrophic, bulbously protuberant with minute microvilli with no distinct intercellular borders. Numerous cryptosporidia in the heterotopic glandular epithelium in the submucosa of cecum and colon on DPI 9 and 10 were found. No differences in the location and degree of cryptosporidial infection between colostrum-fed and colostrum-deprived conventionally reared piglets were found. Sow's colostrum does not appear to protect piglets from C. parvum infection. The role of intestinal microflora in the pathogenesis of cryptosporidiosis in piglets is discussed.     

Effects of age and zinc supplementation on transport properties in the jejunum of piglets

Zinc is effective in the prevention and treatment of post‐weaning diarrhoea and in promoting piglet growth. Its effects on the absorption of nutrients and the secretory capacity of the intestinal epithelium are controversial. We investigated the effects of age, dietary pharmacological zinc supplementation and acute zinc exposure in vitro on small‐intestinal transport properties of weaned piglets. We further examined whether the effect of zinc on secretory responses depended on the pathway by which chloride secretion is activated. A total of 96 piglets were weaned at 26 days of age and allocated to diets containing three different levels of zinc oxide (50, 150 and 2500 ppm). At the age of 32, 39, 46 and 53 days, piglets were killed, and isolated epithelia from the mid‐jejunum were used for intestinal transport studies in conventional Ussing chambers, with 23 μm ZnSO₄ being added to the serosal side for testing acute effects. Absorptive transport was stimulated by mucosal addition of d ‐glucose or l ‐glutamine. Secretion was activated by serosal addition of prostaglandin E₂, carbachol or by mucosal application of Escherichia coli heat‐stable enterotoxin (St_p). Jejunal transport properties showed significant age‐dependent alterations (p < 0.03). Both absorptive and secretory responses were highest in the youngest piglets (32 d). The dietary zinc supplementation had no significant influence on jejunal absorptive and secretory responses. However, the pre‐treatment of epithelia with ZnSO₄ in vitro led to a small but significant decrease in both absorptive and secretory capacities (p < 0.05), with an exception for carbachol (p = 0.07). The results showed that, in piglets, chronic supplementation with zinc did not sustainably influence the jejunal transport properties in the post‐weaning phase. Because transport properties are influenced by the addition of zinc in vitro, we suggest that possible epithelial effects of zinc depend on the acute presence of this ion.     

Cow–Calf Herds in Eastern Germany: Status Quo of Some Parasite Species and a Comparison of Chemoprophylaxis and Pasture Management in the Control of Gastrointestinal Nematodes

Infections with gastrointestinal parasites (Eimeria spp., Cryptosporidium spp., Buxtonella sulcata, Fasciola hepatica, Moniezia spp. and trichostrongyles) and lungworms were monitored in five cow–calf herds in the north German lowlands. Estimated prevalences of infections with Eimeria spp. (predominantly Eimeria bovis) ranged between approximately 2 and 48 %. The highest prevalences were found during late summer and autumn. On one farm Cryptosporidium spp. were detected in July and August (prevalence: 8.5 ± 2.7 % and 6.7 < 2.0 %). The latter finding coincided with diarrhoea in many calves. Buxtonella sulcata was found during the entire study period in highly variable estimated prevalences ranging between zero and 73 %, but without any obvious association with clinical disease. Fasciola hepatica was detected on four out of five farms at estimated prevalences of approximately 1–20 %. Lungworm infections played a minor role in at least three of five study herds. The estimated prevalence of trichostrongyle infections rose from August until November whereas the intensity of infection did not change significantly. No difference in the intensity of infection could be detected between one farm on which infections with gastrointestinal nematodes were controlled only by moving the animals to an uninfected pasture in July, and three other herds on which strategic anthelmintic control was in place.     

Immunogenicity of Murein‐associated Proteins from Temperature‐stressed Streptococcus suis Cultures

We compared immunogenicity in pigs of whole cell lysate proteins (WCP) with murein‐associated proteins (MAP) obtained from a virulent serotype 2 strain of Streptococcus (S.) suis grown at 32 or 42°C. Protein fractions were tested for their ability to induce antibodies in 3‐week‐old piglets by enzyme‐linked immunosorbent assay and Western blot analysis. We found a significant increase in the antibody levels in all sera irrespective of the preparation used for immunization. However, α‐WCP sera showed higher reactivities than α‐MAP sera, and piglets immunized with 32°C preparations (α‐32 sera) showed higher responses than those immunized with 42°C preparations (α‐42 sera). Western blot analysis revealed that α‐WCP sera in part reacted with different proteins when compared with α‐MAP sera. Furthermore, some proteins were only detected by α‐32 but not by α‐42 sera. In conclusion, the results demonstrate the immunogenicity of cell wall MAP of S. suis, and highlight the importance of considering growth conditions in the preparation of subunit vaccines.     

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

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

Life cycle of Isospora suis in gnotobiotic and conventionalized piglets

Isospora suis had 3 asexual and 1 sexual intra-intestinal conventional life cycle. The first asexual generation was most prominent at 2 days p.i. (post inoculation) and produced 2–7 merozoites. The second-generation meronts were prevalent at 3–4 days p.i. and produced 2–12 large merozoites. At 4–5 days p.i. the third generation meronts were prominent and produced 4–24 small crescent shaped merozoites. Mature sexual stages were most prominent at 5–6 days p.i. The stages were most numeroous in the distal half of the small intestine. At 8–9 days p.i. stages morphologically similar to the second generation of meronts reappeared, followed by the further development into third generation merozoites and sexual stages. This was reflected in a prepatent period of 5 days and a biphasic patent period of 5–8 or 9, and 11–14 days p.i.Intraperitoneal injection of liver/spleen and intestinal lymph node homogenates, respectively, from piglets infected 24 and 48 h, previously with high doses of oocysts, resulted in a patent infection 10–12 days post inoculation of the donor piglets. No differences in the life cycle of I. suis were observed between conventionalized and germ-free piglets. An extra-intestinal life cycle of I. suis related to the second patent period was postulated.     

The immediate effects of weaning stress on the hypothalamus‐pituitary‐adrenal alteration of newly weaned piglets

This study was conducted to examine the effects of weaning stress on gene expression of specific markers in hypothalamus‐pituitary‐adrenal (HPA) axis and neuronal activity in the newly weaned piglets. Twelve 28‐days‐old, newly weaned crossbred (Landrace × Yorkshire × Duroc) male piglets from 6 l (2 piglets/l) were randomly categorized into two groups: (a) weaning stress: piglets were separated from their dams, relocated and mixed with the unacquainted domestic piglets for 2 hr (stress, n = 6); (b) no‐stress: piglets stayed with their dams in the farrowing house (NS; n = 6). After weaning stress, all piglets were electrically euthanized and the blood samples/HPA tissues were collected for subsequent analysis, including plasma cortisol and mRNA expression of c‐fos, c‐jun, corticotropin‐releasing hormone (CRH), CRH receptor 1 (CRHR‐1) and adrenocorticotropin hormone receptor (MC2R). Results: Weaning stress significantly (p < 0.05) increased the plasma cortisol level and suppressed the expression of c‐fos and CRH in hypothalamus. In addition, weaning stress enhanced the mRNA abundance of c‐jun and CRHR‐1 in the pituitary gland. No significant differences in the gene expression of MC2R and CRHR‐1 were observed in the adrenal gland between treatment groups. Taken together, HPA involved in weaning stress and CRHR‐1 and c‐jun could be potential markers to evaluate the activation of HPA axis.     

Studies on preweaning piglet diarrhoea

SUMMARY The aim of this study was to determine the cause and risk factors Involved in preweaning piglet diarrhoea. Faecal samples from 2380 diarrhoeic piglets, 5 to 30 days of age, were examined for enteropathogens. Isospora suls oocysts were detected in 53.8% of samples, Escherichia coll in 18.2% and rotavirus in 16.9%. I suis had the widest distribution, being present on 70.9% of 151 piggeries. The onset of diarrhoea occurred mainly between 7 and 14 days (77.5%), peaking at 10 days. Records of 4086 litters from two intensive piggeries were analysed and showed no seasonal variation or effect of sow parity on the incidence of piglet diarrhoea. I suis was the most common enteropathogen associated with diarrhoea in piglets from 5 days of age until weaning.     

The effect of antimicrobial growth promoter withdrawal on the health of weaned pigs in Finland

The use of the antimicrobial growth promoters (AGPs) carbadox and olaquindox has been banned in the European Union (EU) since September 1999. We studied the effects of the withdrawal on the health of weaned piglets on two types of piglet-producing farms (farrowing herds and farrow-to-finish herds) from the different regions of Finland. Farms with no major problems with post-weaning diarrhoea were selected for the study to better evaluate the effect of AGPs alone. Data on production, medication and incidence of diarrhoea were collected from 73 farms during 1 year after the withdrawal. On 29 of these farms, the data collection began 4 months before the withdrawal.

The health management of the pigs is considered good in Finland, and special attention has been paid to improve the husbandry practices and management of the farms. Eighty-two percent of the farms in the study were free of both Mycoplasma hyopneumoniae and Sarcoptes scabiei infection. Brachyspira hyodysenteriae infection was not detected in any of the farms. The median number of sows in the herds was 56.0 (IQR = 43.0; 72.5) in 2000.

The level of antimicrobial use in each herd was classified as low, moderate and high when the percentage of weaned pigs treated for diarrhoea during a 4-month period was 0–5%, 6–19% and ≥20%, respectively. Only on four herds (14%), there was an increase in the level of antibiotic use after the AGP withdrawal, when seasonally corresponding 4-month periods were compared. Fourty-one percent of these 29 farms were categorized as low users of antimicrobials, 38% as moderate users and 21% as high users.

The level of antimicrobial use for treatment of diarrhoea after weaning (and the incidence of diarrhoea in weaned piglets) did not increase significantly after the withdrawal of AGPs from weaner feeds according to farmers’ evaluations. In this study, the Escherichia coli infection was the most-common cause of diarrhoea in weaned pigs. The age at weaning did not change after the withdrawal of AGPs.     

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.     

Field Evaluation of the Effect of In‐Feed Doxycycline for the Control of Ileitis in Weaned Piglets

The aim of this trial was to evaluate the effect of in‐feed doxycycline (DOXY) on the control of ileitis in weaned piglets. On a farm with a previous history of ileitis outbreaks, 288 piglets at the age of weaning (25 ± 2 days old) were divided into four experimental groups, each group comprising three pens with 24 piglets in each pen. Non‐medicated animals served as negative control (NC) group, whereas groups DOXY‐50, DOXY‐125 and DOXY‐250 received doxycycline via feed at 50, 125 and 250 ppm, respectively. Therapy lasted for 14 days followed by an observation period of 28 days. In conclusion, administration of doxycycline at a dose rate of 125 or 250 ppm had beneficial effect compared with the NC group, in terms of the reduction of diarrhoea prevalence, the enhancement of growth performance and the reduction of prevalence of Lawsonia intracellularis in the intestine, as shown either by the PCR method or by specific histopathological examinations. Treatment with 250 ppm of doxycycline for a fortnight interval post‐weaning seems to be beneficial leading to better growth rates of piglets not only during treatment period, but also throughout the whole nursery phase.