Vitamin C plasma concentrations and leg weakness in the forelegs of growing pigs

Four litters (41 pigs) of cross-bred pigs were studied from 6 to 26 weeks of age. Blood samples were collected at 6, 13, 21 and 26 weeks of age and analysed for contents of vitamin C, calcium (Ca), inorganic phosphorus (P) and alkaline phosphatase (ALP). The pigs were examined clinically for foreleg weakness at the ages of 21 and 26 weeks. At the age of 26 weeks the pigs were slaughtered and the right forelegs were examined macroscopically and selected samples were collected for radiological, histological and ultrastructural examination. The prevalence of foreleg lesions was high, with lesions of dyschondroplasia of the distal growth plate of the ulna in 30 pigs, synovitis of the elbow joint in 24 pigs and osteochondritis dissecans of the elbow joint in 25 pigs. At the ages of 21 and 26 weeks, five pigs had evidently crooked forelegs and 14 pigs (age 21 weeks) and 25 pigs (age 26 weeks) had mildly deformed forelegs. The serum levels of Ca, P and ALP were within normal values for growing-finishing pigs. The range of vitamin C concentrations in plasma showed a wide difference (7.1-49.8 mumol/l) but was not associated with deformed forelegs. The serum concentrations of Ca, P and ALP and the plasma concentration of vitamin C differed significantly (P = 0.05) between age groups and there was a significant (P = 0.001) positive correlation between the levels of vitamin C in plasma and the serum levels of ALP at 6 weeks of age. The aim of the present study was to determine if there was any association between the plasma levels of vitamin C and the extent of crooked or deviated forelegs in growing-finishing pigs. We could not find a vitamin C deficiency during the study and no association between low levels of vitamin C in plasma and the presence of deformed forelegs of these 40 pigs.     

Osteochondrosis and arthrosis in pigs. I. Incidence in animals up to 120 kg live weight

Joint and bone lesions in growing pigs are described on the basis of post-mortem examination of 341 gilts, boars or castrates from 10 to 120 kg live weight, and 869 separate bones from pigs between 80 and 115 kg live weight at slaughter. No evidence of rickets or generalized osteodystrophia fibrosa was found. Lesions occurred in both sexes. The typical osteochondral lesions were most often symmetrical, occurred at certain sites in joints and epiphyseal plates and were most obvious in the elbow and stifle joint, and in the distal epiphyseal plate of the ulna. Lesions of varying degree could be demonstrated in most pigs at 90–100 kg live weight. The use of the diagnosis osteochondrosis is suggested for local primary non-inflammatory disturbances which lead to a failure of endochondral ossification in joint cartilage as well as in epiphyseal plates. The diagnosis arthrosis is used when the superficial layer of the joint cartilage is affected. Investigations of the early changes in the medial condyle of the femur suggest that the osteochondral lesions start in the deep layers of the joint cartilage. Arthrosis occurred frequently in the lumbar intervertebral joints of Norwegian pigs. Otherwise the lesions appeared to be identical with those described from other countries.     

IL‐12p40 gene expression in lung and hilar lymph nodes of MPS‐resistant pigs

Mycoplasma pneumonia of swine (MPS) is caused by Mycoplasma hyopneumoniae (M.hp) and is a common chronic respiratory disease of pigs. Recently, a genetically selected variant of the Landrace pig (Miyagino L2) has a lower incidence of pulmonary MPS lesions. We investigated the pathological and immunological characteristics of MPS resistance in these pigs (n = 24) by comparing with the normal landrace pig (control: n = 24). The pathological MPS lung lesion score in MPS‐selected landrace pigs was significantly lower than in the control. The gene expression of interleukin (IL)‐12p40, which acts as a chemoattractant and a component of the bioactive cytokines IL‐12 and IL‐23, was significantly higher at the hilar lymph nodes, lung, and spleen in MPS‐selected landrace pigs than in control landrace pigs, and these were negatively correlated with the macroscopic MPS lung lesion score. In summary, we demonstrate that resistance against MPS in Miyagino L2 pigs is associated with IL‐12p40 up‐regulation, in comparison with normal landrace pigs without the MPS vaccine. In addition, a comparative study of macroscopic MPS lung lesions and IL‐12p40 gene expression in lung and hilar lymph nodes may lead to beneficial selection traits for the genetic selection for MPS resistance in pigs.     

Effect of dietary nutrients on osteochondrosis lesions and cartilage properties in pigs

OBJECTIVE: To evaluate dietary ingredients involved in cartilage and bone metabolism and their influence on osteochondrosis lesions in swine. ANIMALS: 80 crossbred gilts (mean initial weight, 39 kg). PROCEDURES: Pigs (10 pigs/treatment) were fed a corn-soybean meal basal (control) diet or the basal diet supplemented with additional minerals (copper and manganese or silicon), amino acids (proline and glycine; a combination of leucine, isoleucine, and valine; or methionine and threonine), or fatty acids (provided by fish oil) for 84 days. Pigs were then slaughtered and the distal portion of the left femur was collected for determination of osteochondrosis lesions at the femoral condyle. After evaluation of external joint surfaces, the distal portion of the femur was sectioned to evaluate lesions in the growth plate and articular cartilage. Additionally, a cartilage specimen was obtained from the patella for analysis. RESULTS: Pigs fed diets containing high amounts of methionine and threonine or the diet containing all additional ingredients had significantly lower total severity scores, compared with scores for pigs fed the control diet or a diet supplemented with fish oil. Pigs fed diets containing additional proline and glycine, copper and manganese, methionine and threonine, or all additional ingredients had significantly lower overall scores, compared with scores for pigs fed the control diet or a diet supplemented with fish oil. CONCLUSIONS AND CLINICAL RELEVANCE: Dietary manipulation decreased the severity of osteochondrosis lesions, compared with results for pigs fed a control diet. However, additional research on optimal concentrations and combinations of dietary components is needed.     

Evaluation of experimental methods to induce congenital hypothyroidism in guinea pigs for use in the study of congenital hypothyroidism in horses

OBJECTIVE: To develop a method to reliably induce congenital hypothyroidism in guinea pigs (Cavia porcellus) and assess similarities between the resultant developmental abnormalities and those described in horses with congenital hypothyroidism. ANIMALS: 35 female guinea pigs and their offspring. PROCEDURE: Guinea pigs were allocated to control groups or groups treated with a low-iodine diet before and throughout gestation; an s.c. injection of 100 or 200 microCi of radioactive iodine 131 (131I) on day 40 of gestation; or 0.1% propylthiouracil (PTU) continuously in the drinking water, beginning day 3 or 40 of gestation. In all groups, assessments included gestation duration, litter size, proportion of stillborn pups, and laboratory analyses in live pups and dams; postmortem examinations were performed on all pups and dams and selected tissues were examined histologically. RESULTS: Compared with control animals, pups from dams receiving a low-iodine diet or 131I s.c. had mild changes in their thyroid glands but no grossly or radiographically detectable lesions of hypothyroidism. Pups from dams receiving PTU were often stillborn (24/27 pups) and had enlarged thyroid glands (characterized by large, variably sized follicles of tall columnar epithelium and little or no colloid), an incomplete coat, and radiographically detectable skeletal dysgenesis. CONCLUSIONS AND CLINICAL RELEVANCE: Many of the lesions detected in guinea pig pups from the experimentally treated dams were similar to those described in foals with congenital hypothyroidism. Experimental induction of congenital hypothyroidism in guinea pigs may be useful for the study of naturally occurring congenital hypothyroidism in horses.     

Effect of challenge dose and age in experimental infection of pigs with encephalomyocarditis virus

Two experiments were performed to compare the severity of encephalomyocarditis virus (EMCV) infection in pigs. The pigs were challenged with the Greek myocardial strain, at different ages and with different doses. In the first experiment, nineteen susceptible pigs, 40 days old, were divided into three groups and were experimentally infected with 10(6) TCID(50), 10(4) TCID(50) or 10(2) TCID(50) of the Greek EMCV strain. In the second experiment, 10 susceptible pigs, of either 20 or 105 days, were divided into two groups according to age and were experimentally infected with 10(6) TCID(50) of the Greek EMCV strain. In addition, five piglets, each one the same age as its experimental group, were used as uninfected controls. No clinical signs were observed after infection, except a transient temperature rise in some pigs. Another important observation was the difference in mortality between groups. The survival rate of the 40-day-old pigs was inversely related to the viral dose. In these pigs, a positive association between the viral dose and the severity of macroscopical and histopathological lesions of the heart was also evident. Viral isolations from various organs of the challenged 40-day-old pigs increased with the increasing dose level. When challenged with 10(6) TCID(50) of EMCV, there was no difference in the fatality rate of the 20- and 40-day-old pigs, but none of the 105-day-old pigs died. The severity of the macroscopical and the histopathological heart lesions was inversely related to the age of the pigs. Furthermore, viral isolations from the various organs were higher in 20- and 40-day-old pigs than in the older ones. In 40-day-old pigs, neutralizing antibodies linearly increased as the dose increased. These antibodies were consistently lower in 20-day-old pigs. Viraemia, and nasal and faecal excretions were detected in all groups and lasted 1-3 days, except for the 105-day-old pigs whose symptoms lasted for an additional day.     

Effects of divergent selection for leg weakness on angularity of joints in Duroc swine

Sixty Duroc pigs, representing offspring of three lines from the fifth generation of divergent selection for leg weakness, were examined to determine correlated responses in joint angularity. The lines were low, control, and high, with the latter having superior front leg structure. At approximately 100 kg, 10 pigs of each sex and line were scored for front and rear leg structure and movement. The shoulder, elbow, carpal and hock joints were measured for resting angles and range of motion. The model to analyze the data included the effects of line, sire, sex and side and covariable for weight. High-line pigs had significantly smaller (P less than .05) resting angles of the elbow joint than did control- or low-line pigs. The low-line pigs, however, had significantly smaller resting angles at the carpal joint (P less than .01) and greater resting angles at the hock joint (P less than .05) than did control- or high-line pigs. The low-line pigs had fewer degrees extension at the elbow joint and fewer degrees flexion at the carpal joint than did control- or high-line pigs. High-line pigs had fewer degrees of flexion of the elbow joint than did control-or low-line pigs. Resting angles and range of motion for the elbow and carpal joints were less on the left side than on the right side. Males had greater degrees of extension and total degrees of movement at the elbow joint than did females. Selection for different degrees of leg weakness resulted in accompanying alterations in angularity of joints.     

Differences in metabolic parameters and gene expression related to osteochondrosis/osteoarthrosis in pigs fed 25-hydroxyvitamin D3

Osteochondrosis/osteoarthrosis (OC/OA) are common terms for various joint pathologies that occur in pigs. Pathologies that may contribute to these disorders have been described, but the primary cause(s) remain unknown. We hypothesised that as OC has some similarities to dyschondroplasia, which involves a failure of growth plate chondrocytes to fully differentiate and hypertrophy, treatment with 25-hydroxyvitamin D3 (25-D) might reduce the incidence and/or severity of lesions in pigs, as it does in chickens with dyschondroplasia. Control pigs were fed a commercial diet ad libitum. In the treated group this diet was supplemented with 25-D at 0.1 mg/kg. Ten pigs from each of the control and treated groups were sampled at 7, 12, 16 and 21 weeks. Treatment with 25-D had no effect on the incidence or severity of OC/OA lesions. Cartilage dry weight, total collagen content and proteoglycan content, and plasma levels oftotal calcium, inorganic phosphorous, vitamin C, insuline-like growth factor-I, parathyroid hormone and tumour necrosis factor alpha were unaffected by treatment. In addition, none of these parameters were correlated with the incidence or severity of OC/OA lesions. The mRNA expression levels of 21 out of 23 genes assayed by RT-PCR were unaltered in articular cartilage from OA lesion samples as compared to normal articular cartilage. However, collagen type II was reduced and collagen type X increased in OA lesion and near lesion samples. These results suggest that OA in pigs may share some features of osteoarthritis in other mammalian species.     

Osteochondrosis and arthrosis in pigs. 3. A comparison of the incidence in young animals of the Norwegian Landrace and Yorkshire breeds

An investigation concerning the occurrence of osteochondrosis and arthrosis in 2 materials totalling 63 pigs of the Landrace breed and 63 of the Yorkshire breed is described. The animals were bred under the same conditions of feeding and housing. The differences should therefore mainly be of genetic origin. Both breeds were highly improved, Landrace the most. In general, Yorkshire pigs showed a lower incidence and a less marked degree of osteochondrosis and arthrosis than Landrace pigs. Statistically significant differences (P < 0.01) were demonstrated in the distal epiphyseal plate of the ulna, in the intervertebral joints of the lumbar region and in the medial condyle of the femur in 1 of the materials. The Landrace pigs had longer bodies, broader hindquarters, shorter femurs, and the stifle had a different shape as compared with Yorkshire pigs. There thus seemed to be a connection between exterior features, joint and bone shape and the occurrence of joint lesions. Differences among litters within breed were also demonstrated.     

Actinobacillus pleuropneumoniae osteomyelitis in pigs demonstrated by fluorescent in situ hybridization.

Necrotizing osteomyelitis and fibrinopurulent arthritis with isolation of Actinobacillus pleuropneumoniae serotype 2 is reported in two pigs from a herd with lameness and mild coughing problems among 8 to 12-week-old pigs. Application of fluorescent in situ hybridization targeting 16S ribosomal RNA of A. pleuropneumoniae in formalin-fixed tissue was performed to verify the association of A. pleuropneumoniae with the bone and joint lesions. By in situ hybridization A. pleuropneumoniae was demonstrated as multiple microcolonies or single cells dispersed in focal fibrinonecrotizing pleuropneumonia, in joints with arthritis, and in bone necroses including lysis of growth plate and suppurative inflammation in the adjacent trabecular metaphysis, thus demonstrating that well-known infections manifest new, unusual lesions.     

Occurrence and associated lesions of Pasteurella multocida in porcine bronchopneumonia

With the aim to extend the present knowledge on possible systemic spreading of Pasteurella multocida in pigs with bronchopneumonia, the occurrence and associated lesions of P. multocida were described by comparing cultural detection, pathological evaluation and in situ hybridization of P. multocida in lungs, hearts and kidneys from cases of porcine bronchopneumonia. P. multocida was cultivated from the lung lesions in 114 out of a total of 148 cases of porcine bronchopneumonia. Among the 114 cases, P. multocida was also cultivated from the pericardial sacs of 40 pigs and the kidneys of seven pigs. Gross lesions and histological findings included a variety of type and stages of bronchopneumonia in connection to the isolation of P. multocida. Furthermore, chronic fibrous pericarditis, interstitial nephritis and a high proportion of lympho-histocytic nephritis were observed. In situ hybridization identified P. multocida in the majority of the lungs, none of the hearts and in half of the kidneys examined. The results show a possible low rate of systemic spreading of P. multocida from lung lesions in pigs with bronchopneumonia.     

Biological, chemical and pathohistologic study of the skin in papular dermatitis in fattened pigs

We examined the skin samples from 23 fattened pigs with papular dermatitis (PD) and from 17 pigs showing no skin lesions; the live weight of the pigs was from 95 to 105 kg and the pigs came from a large fattening house D that is located in the region where the mines are frequent (lignite extraction). It was only in 26% of pigs with PD where the common ectoparasites Haematopinus suis and Sarcoptes scabiei var. suis were found out. The skin lesions were not fluorescent in the light of Wood's lamp. The fungi Aspergillus flavus, A. fumigatus, A. tereus, Chrysosporium, Mucor sp., Scopulariopsis sp. were sporadically isolated from the skin lesions in 39% of pigs with PD. In 65% of pigs with PD Staphylococcus aureus was isolated from the skin lesions, which was not found in pigs without dermal lesions. Staphylococcus epidermidis was isolated in 87% of pigs with PD and 58% of pigs without any skin changes. The skin lesions were virus-free. Increased concentrations of cadmium and mercury were observed in the skin of pigs with PD and in control pigs. The concentration of aflatoxin B1 in the skin of the two groups of pigs did not exceed the level of 5 micrograms X kg-1, in PD pigs it was, however, twice higher than in the clinically healthy pigs. The residues of chlorinated hydrocarbons in the subcutaneous fat were not higher than the certified hygienic levels. Both epidermis and corium are affected by inflammatory lesions. At the beginning, neutrophil infiltration with necrotization of epithelial cells prevails. It is followed by capillary proliferation with angioblast and fibroblast multiplication and straggled lymphoid infiltration. It is necessary to distinguish by differential diagnostics: swine pox, parakeratosis of swine, lesions of impetigo contagiosa suum, pustular dermatitis and scab of swine, and from rarely occurring skin diseases of swine hypotrichosis cystica suis and demodicosis of swine. No conclusions can be drawn explicitly on the etiology and pathogenesis of papular dermatitis in fattened pigs. We must study the potential interactions of negative environmental factors with regulating homeostatic and adaptation mechanisms in fattened pigs.     

Leg weakness in pigs. I. Incidence and relationship to skeletal lesions, feed level, protein and mineral supply, exercise and exterior conformation

Out of 373 Landrace boars and gilts involved in feeding experiments, 18.2 % showed severe degree leg weakness and 30 % mild degree leg weakness at 100 kg live weight. Of the boars at pig A.I. stations 23.9 % were slaughtered because of leg weakness, 75 % of these being under 1½ years. The practical significance of leg weakness is greatest in young breeding stock. High feed level in slaughter pigs resulted in poorer locomotory ability than medium feed level. Exercise resulted in pigs showing better movements. Variations of minerals and protein within limits used in practical feeding did not have any influence on the incidence of leg weakness. There was no statistically significant relationship (P > 0.05) between joint lesions and locomotory ability in pigs at 100 kg live weight, although severe lesions seemed to lead to poorer mobility. The joint regions which seemed to be mainly involved in severe degree leg weakness in boars were the elbow and stifle joints (31.3 %), the lumbar intervertebral joints (28.1 %) and the hip region (15.6 %). There was a significant relationship between narrow lumbar region, broad hams, large relative width between the stifle joints, and poor locomotory ability in slaughter pigs.     

An evaluation of nonsuppurative joint disease in slaughter pigs

Fifty-two joints from pigs with nonsuppurative joint disease from a local abattoir were examined grossly, histologically, and microbiologically in order to establish macroscopic differences between degenerative arthropathy and arthritis due to an infectious organism. The joints were grouped grossly according to the type and severity of lesions of the synovial membrane and cartilage, and microscopically according to the severity of synovial membrane lesions. Osteochondrosis and Erysipelothrix rhusiopathiae were the most common causes of nonsuppurative joint disease in the joints examined. The major macroscopic differences between these two arthropathies were in the nature and severity of the synovial and cartilaginous lesions and involvement of the lymph node draining the diseased joint. Typically, in osteochondrosis, the changes are feathery hypertrophy of villi, focal full-thickness cartilage buckles, ulcers or flaps, and no change in the draining lymph node, whereas in Erysipelothrix- caused arthritis, the villous hypertrophy is severe and polypoid in nature, there is diffuse erosion of articular cartilage, and the draining lymph node is consistently hypertrophic and often cystic.     

Chronological study of Mycoplasma hyopneumoniae infection, seroconversion and associated lung lesions in vaccinated and non-vaccinated pigs

A field trial was conducted to study Mycoplasma hyopneumoniae (Mh) infection dynamics by nested polymerase chain reaction (nPCR) and serology in pigs of a farm affected by enzootic pneumonia (EP). Moreover, correlation of Mh detection at different respiratory tract sites with presence of EP gross and microscopic lung lesions was assessed. These parameters were studied and compared between vaccinated (two doses at 1 and 3 weeks of age versus one dose at 6 weeks of age) and non-vaccinated pigs. Animals were monitored from birth to slaughter by nPCR from nasal swabs and by serology. From 3 to 22 weeks of age, an average of three pigs per treatment and per batch were necropsied (n = 302). The remaining pigs were sent to the slaughter (n = 103). Nasal, bronchial and tonsillar swabs were taken from the necropsied/slaughtered pigs; gross and microscopic EP-suggestive lung lesions were also assessed. Single and double vaccination resulted in earlier seroconversion and higher percentage of Mh seropositive pigs compared to control group. At slaughter, double vaccinated pigs showed lower percentage of EP-compatible gross lung lesions and lower Mh prevalence at upper respiratory tract sites (nasal cavity and tonsil) than control pigs.     

1株猪鼻支原体的分离鉴定及致病性

猪鼻支原体是猪场感染率极高的一种支原体,可引起多发性浆膜炎、关节炎等症状。目前尚未建立标准的猪鼻支原体发病模型,也缺乏标准强毒株。本研究从某猪场发病猪的关节液中分离得到一株支原体,通过PCR检测、菌落形态观察、菌体形态电镜分析、菌株MLST分型等方法对其进行了鉴定,确认其为猪鼻支原体。为评价菌株致病性,将该分离株接种1月龄自然分娩不吃初乳猪（SF-pCD猪）,试验猪在感染后出现关节肿胀、跛行等临床症状,日增重显著低于对照组,并出现部分死亡。剖检结果显示感染组出现胸膜炎、腹膜炎、心包炎及关节炎,肺部组织病理分析显示为间质增宽,无虾肉样病变。从发病猪的扁桃体、肺、心及关节积液中可再次分离到攻毒株。综上,本研究分离获得一株猪鼻支原体,人工感染猪后可出现典型的发病症状,猪鼻支原体发病模型的建立为致病机制及疫苗研究奠定了重要的基础。     

Experimental dual infection of pigs with an H1N1 swine influenza virus (A/Sw/Hok/2/81) and Mycoplasma hyopneumoniae

Dual infection of pigs with swine influenza virus (SIV) and Mycoplasma hyopneumoniae was carried out to compare the clinical and pathological effects of dual infection in caesarian derived and colostrums deprived (CDCD) pigs, with that of a single infection with M. hyopneumoniae. In Experiment 1, 40-day-old CDCD pigs were inoculated only with SIV (A/Sw/Hok/2/81, H1N1). The virus was isolated from nasal swabs for 5-6 days. None of these pigs showed clinical signs of infection throughout the experimental period. These results suggested that this strain can infect pigs but is only slightly pathogenic when it is inoculated singly to a CDCD pig. In Experiment 2, 60-day-old CDCD pigs were inoculated with M. hyopneumoniae and then were inoculated with SIV (A/Sw/Hok/2/81) at 1 week (MHYO-7d-SIV-7d group) or 3 weeks (MHYO-21d-SIV-7d group) after M. hyopneumoniae inoculation. Macroscopically, dark red-to-purple lung lesions were observed in all of pigs at 14 or 28 days post-inoculation. Percentages of dark red-to-purple lung lesions in dual infection groups (MHYO-7d-SIV-7d group: 18.7 +/- 4.2%, MHYO-21d-SIV-7d group: 23.0 +/- 8.0%) were significantly (P < 0.05) increased compared to those of each control group in which pigs were inoculated only with M. hyopneumoniae (MHYO-14d group: 4.7 +/- 2.9%, MHYO-28 group: 3.3 +/- 2.4%). Microscopically, bronchial epithelial lesions (epithelial disruption, degeneration, hyperplasia and formation of microabscess) were frequently observed in dark red-to-purple lung lesions of only the dual infection groups. These results demonstrate that the lung lesion of pigs inoculated with M. hyopneumoniae and SIV is more severe than that of pigs inoculated only with M. hyopneumoniae.     

Effects of the timing of the administration of Mycoplasma hyopneumoniae bacterin on the development of lesions associated with porcine circovirus type 2

To determine whether there is an effect of the timing of vaccination on porcine circovirus type 2 (PCV-2) replication and PCV-2-associated lesions, 78 pigs were randomly assigned to eight groups: group 1 (10 pigs) was vaccinated with a commercial Mycoplasma hyopneumoniae vaccine at two and four weeks of age, group 2 (nine pigs) was vaccinated at four and six weeks of age, group 3 (10 pigs) at six and eight weeks of age and group 4 (10 pigs) at eight and 10 weeks of age; group 5 (nine pigs) was vaccinated once with a double dose at four weeks of age, and group 6 (10 pigs) was vaccinated once with a double dose at eight weeks of age. Groups 7 and 8, both of 10 pigs, were not vaccinated. At eight weeks of age, the pigs in groups 1 to 7 were inoculated with PCV-2. Fourteen days after they had been inoculated, the pigs in groups 1, 4 and 5 had significantly (P<0.05) more copies of the PCV-2 genome in their serum than the unvaccinated pigs. Microscopically, 14 of the 68 inoculated pigs had normal lymphoid tissues, 40 had mild PCV-2-associated lymphoid lesions and 14 had moderate lesions. The mean overall lymphoid lesions (lymphoid depletion, granulomatous inflammation, and quantity of PCV-2 antigen in spleen, tonsil, and five lymph nodes) were significantly (P<0.05) more severe in groups 4 and 5 than in groups 2, 3, 7 and 8.     

Growth performance,immune status,gastrointestinal tract ecology,and function in nursery pigs fed enzymatically treated yeast without or with pharmacological levels of zinc

Growth performance and physiological responses of nursery piglets when fed enzymatically treated yeast (HY40) and pharmacological ZnO alone or in combination were investigated. A total of 144 pigs (21 d old, BW 7.32 ± 0.55 kg) were placed in 36 pens (4 pigs/pen). Pigs were randomly assigned to one of four dietary treatments (n = 9): 1) control corn-wheat-soybean meal diet (control), 2) control + HY40 (HY40), 3) control + (ZnO) and 4) control + HY40 + ZnO (HY40+ZnO). Inclusion of HY40 and ZnO was 0.5% and 3,000 ppm in phase I (days 0 to 14), respectively, and halved in phase II (days 15 to 42). All diets contained 0.2% TiO₂ for determination of apparent total tract digestibility (ATTD) of components. Body weight and feed disappearance were recorded weekly. One pig per pen was killed for organ weights, blood, and tissue samples on day 14. Except for phase II, when HY40 + ZnO pigs had greater average daily feed intake (P = 0.004) than all other treatments, there were no (P > 0.05) interactions between HY40 and ZnO on growth performance. Pigs fed HY40 or ZnO containing diets were heavier (P < 0.05) than pigs fed without by the end of the study. On day 14, pigs fed additives exhibited higher (P ≤ 0.009) ATTD of dry matter (DM) and gross energy (GE) than control pigs. On day 28, pigs fed control, HY40, and HY40 + ZnO had greater (P ≤ 0.022) ATTD of DM, crude protein, and GE than piglets fed ZnO only. Pigs fed HY40 + ZnO had lower ileal digesta Escherichia coli concentration (P < 0.05) than HY40 and control pigs. Ileal digesta of pigs fed ZnO diets had higher lactobacillus to E. coli ratio (1.44 vs. 1.20; P = 0.001), exhibited higher concentrations of acetic (P = 0.01) and butyric acid (P = 0.01) but lower lactic (P = 0.02) and total short chain fatty acids (P = 0.033) than pigs fed non-ZnO diets. Greater (P < 0.05) mRNA expression of nutrient transporters, tight junction proteins, and fecal excretion of zinc (Zn) was observed in ZnO pigs relative to non-ZnO pigs. Pigs fed HY40 diets had greater (P = 0.002) villus height to crypt depth ratio (VH:CD) than non-HY40 pigs. The concentration of plasma IgA was higher (P = 0.04) in HY40 + ZnO pigs relative to other pigs, whereas HY40 pigs showed higher (P < 0.001) jejunal IgA than non-HY40 pigs. Although the mode of action of HY40 and ZnO differed, the present study indicated that HY40 improved growth performance and jejunal function and immunity, making HY40 an effective alternative to pharmacological ZnO in nursery pigs feeding programs.