The dose-response relationship between the amount of straw provided on the floor and gastric ulceration of pars oesophagea in growing pigs.

The aim of the present study was (1) to determine the dose-response relationship between the amount of straw provided on the floor and oesophageal ulceration in pigs kept under typical Danish production conditions (18 pigs/pen, 0.7m2/pig, partly slatted floor, ad libitum access to feed), (2) to reveal whether straw ingestion explains the effect of straw provision on the stomach health and (3) to elucidate the effect of straw ingestion on the stomach conditions. Data were collected at slaughter (approximately 100kg body weight) on pigs provided with straw amounts in the range 10g to 500g wheat straw/pig/day from 30kg body weight and fed a wheat-based pelleted feed added 15% non-heated and non-pelleted rolled barley. Aims (1) and (2) included 712 pigs kept in 42 pens, whereas (3) was studied on a subset of 37 pigs with either none or obvious amounts of straw in the stomach. The amount of straw provided affected stomach health in a curvilinear manner. Provision of up to approximately 300gstraw/pig/day progressively decreased the risk of oesophageal ulceration and scarring. At larger amounts of straw the ulceroprotective effect of straw was reduced which requires further investigation. Straw ingestion appeared to be an essential intermediary factor for the improvement of stomach health. The number of pigs without straw in the stomach decreased linearly with the logarithm of the amount of straw provided, which explained the effect of straw provision on stomach health. The structure of the stomach contents increased as revealed by the increased weight and dry matter content and decreased sedimentation of the digesta. Provision of approximately 300gstraw/pig/day on the floor may be a potential strategy to reduce, but not inevitably eliminate, oesophageal ulceration in pigs in commercial pig production.

Grading of shoulder ulcerations in sows by biopsies.

Shoulder ulcerations can be graded postmortem from 0 to 4 on a pathoanatomical scale. However, veterinarians and farmers express difficulties evaluating the grade of the lesions antemortem. Accurate grading is needed in order to comply with veterinary instruction in relation to the Danish legislation, stating that sows with shoulder ulcers grade 3 or 4 must be kept loose and have access to soft bedding. Thus, the aim of the present study was to evaluate if biopsies from the center of a shoulder ulcer can be used to point out animals for which an intervention must be initiated. Postmortem, a punch biopsy was sampled from the center of the ulceration or from the tissue overlaying the tuber spina scapula. Afterward, the shoulders were cross-sectioned and evaluated grossly and histologically ("gold standard"). In total, 121 shoulders were included in the study, and the diagnostic value of a punch biopsy in grading shoulder ulcerations was evaluated. The results showed a sensitivity of 0.78, a specificity of 0.98, a positive likelihood ratio of 38.36, and a negative likelihood ratio of 0.22. The agreement between the cross-section evaluation and the punch biopsy was found to be 0.90 by calculating the Cohen kappa value. In conclusion, a single punch biopsy from the center of an ulcer is useful for determining the grade of a shoulder ulcer and can be used to facilitate the identification of sows with ulcers requiring an intervention.

The effect of dietary fatty acids on post-operative inflammatory response in a porcine model.

The potential anti-inflammatory effects of dietary fish oil (FO) have been studied in numerous clinical trials. However, variation in lifestyle and morbidity among patients can be difficult to control. In the present study, the impact of a 3-week dietary pre-treatment with 10% (w/w) FO (n 28), sunflower oil (SO, n 28), or animal fat (AF, n 28) was evaluated with respect to post-operative responses in inflammatory markers in a porcine model on aortic vascular prosthetic graft infection. In the early post-operative period (0 < day ≤ 3), FO suppressed whole blood IL-8 and tumor necrosis factor-α responsiveness to LPS stimulation, decreased peripheral leukocyte IL-8 mRNA abundance, reinforced an increase in total leukocyte count, and counteracted a decrease in mononuclear leukocyte count compared with SO. In the late post-operative period (3 < day ≤ 14), FO increased total leukocyte count and showed higher maximum CRP and haptoglobin concentrations compared with SO. Compared with AF, FO decreased peripheral leukocyte IL-8 mRNA abundance in the early post-operative period, and increased total leukocyte count and maximum CRP concentration in the late post-operative period. In conclusion, the post-operative response in a number of inflammatory markers was affected by FO, and this was most apparent compared with SO.

Effects of dietary n-3 and n-6 fatty acids on clinical outcome in a porcine model on post-operative infection.

The present study was performed to evaluate the effects of dietary n-3 and n-6 long-chain PUFA (LC-PUFA) on clinical outcome in a porcine model on early aortic vascular prosthetic graft infection (AVPGI). A total of eighty-four pigs were randomised to a 35 d dietary treatment with 10 % (w/w) fish oil (rich in n-3 LC-PUFA), sunflower oil (rich in n-6 LC-PUFA) or animal fat. After 3 weeks of dietary treatment, the pigs had an aortic vascular prosthetic graft inserted, and it was inoculated with Staphylococcus aureus (106 colony-forming units). Changes in selected plasma and erythrocyte n-3 and n-6 LC-PUFA concentrations and in plasma PGE2 metabolite concentration were determined in the 3-week preoperative period. Clinical signs of infection, i.e. rectal temperature, hindquarter function, general appearance and feed intake, were monitored daily in the 14 d post-operative period, and, finally, daily body-weight gain was determined in both periods. The preoperative changes in plasma and erythrocyte n-3 and n-6 LC-PUFA concentrations reflected the fatty acid compositions of the dietary treatments given, and plasma PGE2 metabolite concentration decreased in the fish oil treatment (P < 0·001). In the post-operative period, feed intake (P = 0·004) and body-weight gain (P = 0·038) were higher in the fish oil treatment compared with the sunflower oil treatment. The dietary treatments did not affect the number of days pigs were showing fever, weakness in the hindquarters or impaired general appearance. In conclusion, preoperative treatment with dietary fish oil compared with sunflower oil improved clinical outcome in pigs with AVPGI by improving feed intake and body-weight gain post-operatively.

Ontogeny and characterization of blood leukocyte subsets and serum proteins in piglets before and after weaning.

Existing knowledge about the development of the porcine immune system was extended by phenotypic characterization of leukocyte subsets and with assessment of Mannan-Binding Lectin (MBL) and immunoglobulin concentrations in peripheral blood of healthy piglets. Single-color and/or double-color flow cytometry using monoclonal antibodies against CD1, CD3, CD4, CD8a CD14, CD21, CD172 (SWC3a), CD284 (TLR4), SLA I, and SLA II were performed to identify T-lymphocyte subsets, B-lymphocytes, monocytes, and granulocytes. ELISA was used to measure the concentration of serum proteins. Several of the analyzed parameters seem to be affected at the time of weaning which took place at 4-5 weeks of age. Using principal component analysis, all analyzed variables - except one - were grouped into 8 factors with distinct developmental profiles. Several of these factors revealed an apparent suppression, a steady state or an acceleration of the developmental age profiles around weaning. In conclusion, results indicate that weaning suppresses a broad spectrum of adaptive immune variables and that this was evident immediately after weaning as well as after a lag period of about one week. On the contrary, variables of the innate immune system seem to be stimulated immediately after weaning. At the time considered to have the highest infection pressure T-cells and TLR4+ cells were markedly enhanced, whereas the expression of SLA I did not seem to be affected by weaning.

MHC expression on spleen lymphocyte subsets in genetically resistant and susceptible chickens infected with Marek's disease virus.

Resistance and susceptibility to Marek's disease (MD) are strongly influenced by the chicken major histocompatibility complex (MHC). In this study, splenic lymphocytes from MD-resistant and MD-susceptible chickens of three MHC genotypes (B21/B21, B19/B21, and B19/B19) were analyzed by flow cytometry for MHC surface expression. In the spleen, constitutive MHC class I surface expression was found to be highest in homozygous B19, lowest in homozygous B21, and intermediate in heterozygous B19/B21 animals. This was observed on CD4(+), CD8(+), and Bu-1(+) splenic lymphocytes. Chickens of all three genotypes were subjected to infection with MD virus (GA strain) and spleen samples from infected as well as MHC-matched negative controls were analyzed at 1, 4, and 8 wk post-infection (p.i.). It was observed that MDV induced an increase in MHC class I expression late in the infection. Thus, MHC class I was increased on the surface of CD4(+) cells from infected chickens of all genotypes at 4 and 8 wk p.i. compared with negative controls. Also, MHC class I expression was increased on CD8(+) cells from infected chickens of all genotypes at 4 and 8 wk p.i., except for the homozygous B19 animals, that showed no increase at 8 wk p.i. MDV-induced differences in MHC class II surface levels were also found. Thus, MHC class II expression was increased on CD4(+) cells from infected B19/21 and B21/B21 chickens at 4 wk p.i., and also at 8 wk p.i. on CD4(+) cells from infected B19/B21 animals. MHC class II expression was increased on CD8(+) cells from infected chickens of all genotypes at 4 wk p.i. These findings suggest that MDV infection in vivo increases the level of MHC surface expression on splenic T cells, indicating a possible role in immunity against MDV.