The kinetics of cytokine production and CD25 expression by porcine lymphocyte subpopulations following exposure to classical swine fever virus (CSFV)

Surface expression of IL-2R-alpha (CD25) is widely used to identify activated lymphocyte populations, while interferon-gamma (IFN-gamma) levels have been shown to be a good indicator of cell-mediated immunity (CMI) in pigs. To investigate the relationship between these two parameters, we developed an intracellular cytokine-staining assay and studied the kinetics of cytokine (IFN-gamma and interleukin-10, IL-10) production relative to CD25 expression in porcine lymphocyte subpopulations, following immunization with a classical swine fever (CSF) vaccine. The number of activated memory T cells (CD4(+)CD8(+)CD25(+) cells) increased slightly in the peripheral blood mononuclear cell (PBMC) population soon after vaccination, then diminished within a few weeks. The number of activated cytotoxic T cells (CD4(-)CD8(+)CD25(+) cells) peaked approximately 2 weeks after the memory population. Although the number of IFN-gamma producing cells detected in this experiment was relatively low, the CD4(+)CD8(+) T cells were major IFN-gamma producers in the PBMCs throughout the experiment. In another experiment, CSF-vaccinated pigs were challenged with a virulent classical swine fever virus (CSFV), and the kinetics of CD25 expression and cytokine productions were monitored. Following exposure to the virus, the number of IFN-gamma producing cells in the PBMCs increased markedly in both the vaccinated and unvaccinated groups. The CD4(-)CD8(+) cells were major IFN-gamma producing cells in vaccinated pigs, while both CD4(+)CD8(+) and CD4(-)CD8(+) populations contributed to the IFN-gamma production in the control group. Interestingly, the enhanced IFN-gamma production was not associated with the upregulation of CD25 expression following the CSFV challenge. In addition, exposure to the virulent CSFV significantly increased interleukin-10 production by the CD4(-)CD8(+) populations in PBMCs of the unvaccinated pigs. Taken together, our results indicated that CD25 expression and IFN-gamma production were not tightly associated in porcine lymphocytes. In addition, the CD4(-)CD8(+) lymphocytes of the PBMCs played a major role in cytokine productions following the CSFV challenge.     

Production of eosinophil chemoattractant activity by ovine gastrointestinal nematodes

Eosinophilia is a well documented feature of helminth infections but the precise nature of the interaction between parasite and eosinophil remains an enigma. This paper describes experiments demonstrating that ruminant gastrointestinal trichostrongyles produce potent chemoattractant activity for ovine bone marrow-derived eosinophils in vitro. This activity was initially identified as a constituent of whole worm extracts of third and fourth larval (L3, L4), and adult stages of Teladorsagia circumcincta, and adult Haemonchus contortus. Similar activity was detected in excretory/secretory (E/S) material derived from live T. circumcincta L3. Subsequently, by adapting the assay technique to incorporate live worms directly into the system, it was shown that L3 of both T. circumcincta and H. contortus produced eosinophil chemoattractant activity. In contrast, neither whole worm extracts, or E/S preparations from mixed stages of the free-living nematode Caenorhabditis elegans contained eosinophil chemoattractant activity, and there was no evidence of chemoattractant production by live C. elegans. The results described are challenging to the traditional dogma that eosinophils are host-protective effector cells, and raise the intriguing possibility that ovine nematodes actively encourage recruitment of eosinophils. Local eosinophil-mediated mucosal damage, comparable to that seen in the asthmatic lung, may then provide a permissive local microenvironment for the parasite. Moreover, if they prove important for pathogenicity, nematode chemoattractants could offer future potential as novel therapeutic targets.     

Effects of supplemental vitamin E during the mature period on the reproduction performance of Taiwan Native Chicken cockerels

One-day-old Taiwan native male chicks were fed with maize-soybean rearing diets without supplemental vitamin E to 23 weeks of age. From 23 to 52 weeks of age, the cockerels (n = 90) were assigned at random to 5 dietary treatments and fed with maize-soybean diets supplemented with 0, 20, 40, 80 and 160 mg/kg of vitamin E (dl-alpha-tocopherol acetate). Pullets (225) of the same age were fed with standard diets throughout. They were artificially inseminated with one dose of 0.04 ml/bird intact and 5-fold diluted pooled semen at 31 to 43 weeks of age and at 49 weeks of age, respectively. The criteria evaluated included: semen quality, fertility and maximum and effective duration of fertility, blood characteristics, body and testes weight. Supplemental vitamin E did not affect cockerels' effective duration of fertility and percentage of fertility. However, when pullets were inseminated with diluted semen, supplementing 160 mg/kg vitamin E increased the maximum duration of fertility at 49 weeks of age. Cockerels receiving 40 to 160mg/kg supplements had higher sperm viability and motility after 39 weeks of age and those fed 80 mg/kg had higher sperm concentration at 39 weeks of age. Cockerels receiving supplements of more than 40 mg/kg vitamin E had higher body weight gain. Plasma cholesterol and testosterone were not affected by supplemental vitamin E. However, plasma luteinising hormone (LH) concentration was lower in cockerels fed 160 mg/kg. Lack of supplemental vitamin E over 39 weeks was associated with lower semen quality but did not reduce the proportion of fertile eggs laid by inseminated hens, perhaps because the insemination dose compensated for low sperm quality. We found that the maximum duration of fertility might be improved by supplementing 160 mg/kg vitamin E at 49 weeks of age.     

Does l‐Asparaginase Influence Efficacy or Toxicity When Added to a Standard CHOP Protocol for Dogs with Lymphoma?

The purpose of this study was to evaluate response rates, 1st remission duration (FRD), and toxicity in dogs with previously untreated lymphoma receiving an identical CHOP-based combination chemotherapy protocol with or without L-asparaginase (LASP). One hundred fifteen dogs with lymphoma were scheduled to receive an identical CHOP-based chemotherapy protocol that included L-ASP. However, because of manufacturer-imposed random rationing, 31 dogs did not receive L-ASP as scheduled. The 2 treatment groups were statistically similar with respect to signalment and presence of historical negative prognostic factors. No difference was observed in the median FRD whether dogs did or did not receive L-ASP (206 versus 217 days, respectively; P = .67). No difference was observed in the median overall survival times between dogs receiving or not receiving L-ASP (310 versus 308 days, respectively; P = .84). No statistical difference was observed with respect to overall response rate between dogs that did or did not receive L-ASP (89.3% versus 87.1%, respectively; P = .75). Complete response rates between the groups also were no different (83.3% and 77.4% for L-ASP and non-L-ASP groups, respectively; P = .59). Prevalence of toxicity (neutropenia, diarrhea, or vomiting) and treatment delays (P = .80) also were similar between groups. The results of this study suggest that exclusion of L-ASP in this multidrug protocol does not significantly impact outcome. Therefore, it may be more appropriate to reserve the use of L-ASP for treating relapse in dogs with lymphoma that have failed induction therapy.     

Some physiological responses associated with reduced wool growth during blowfly strike in Merino sheep

OBJECTIVE: To examine the effect on wool growth of physiological changes associated with experimental flystrike in superfine Merino wethers. DESIGN: An animal house study comparing experimentally fly struck sheep with non-infected control groups that were pair fed or fed ad libitum. PROCEDURE: Sheep in the blow fly larval challenge group were each artificially infected with 500 first instar larvae per day for 8 days. Infections were terminated with insecticide on day 10. For all sheep, live weight change, feed intake and body temperature were monitored and blood collected for analysis of haematology, cortisol, serum haptoglobin, serum amyloid A and the pro-inflammatory cytokines, TNFa, IL-1 b, IL-6 and IL-8. Wool growth and staple strength were examined 4 months after infection. RESULTS: Experimental fly strike included moderate fever, depressed feed intake, and elevated cortisol, IL-6, serum amyloid A and haptoglobin. Staple strength was significantly decreased in struck sheep and did not differ between wool from sites adjacent to and remote from strike lesions. CONCLUSIONS: The results suggest that depression in feed intake alone is not sufficient to account for the decline in staple strength seen during fly strike. Cortisol, IL-6 and metabolic consequences of the acute phase response are likely to be major contributors to the systemic effects of blowfly strike on wool.     

Effect of amount and source of supplemental dietary vegetable oil on broiler chickens exposed to aflatoxicosis

1. Addition of sunflower oil (SFO) at 30 or 60 g/kg or three vegetable oils, namely SFO, soybean (SBO) or groundnut (GNO), at 30 g/kg to isocaloric and isonitrogenous broiler chicken diets were evaluated for possible counteractive effects against aflatoxin (AF) (0.3 microg B1/g diet) from 0 to 42 d of age. 2. Body weight, food intake and serum concentration of protein were lower in the AF group than in the control, whereas in the SFO and SBO supplemented groups they were comparable with those of the control. Sunflower oil at both concentrations exerted similar effects on growth. Groundnut oil did not improve growth or food intake in AF-fed birds. 3. The serum concentration of cholesterol and triglycerides decreased with AF feeding and was increased by supplementation of any of the three oils both in the control and in AF-fed groups. 4. Liver and giblet weight and liver fat content were increased by AF; these effects were countered by dietary oil inclusion, except for liver weight at 60 g/kg SFO. Weights of pancreas and gall bladder were increased by AF. Oil supplementation reduced the weight of pancreas in chickens given AF. 5. Humoral immune response was depressed by AF and dietary oil supplementation (particularly SFO or SBO) countered this effect. Other variables, namely, serum gamma glutamyl transferase activity, bone mineralisation, weights of lymphoid organs, kidney and adrenals, ready-to-cook yields and fat content in muscle and skin showed little or no effect of dietary oil supplementation. 6. It is concluded that dietary inclusion of SFO or SBO at 30 g/kg may alleviate the adverse effects of 0.3 microg/g of AF B1 in commercial broiler chickens. Groundnut oil, although showing beneficial effects on some biochemical variables, failed to improve growth performance.     

Oral malignant melanoma – the effect of coarse fractionation radiotherapy alone or with adjuvant carboplatin therapy

A retrospective study was undertaken of dogs presented to the Animal Health Trust for treatment of oral malignant melanoma, without radiographic evidence of pulmonary metastases. Group 1 (n = 13) received radiotherapy of the primary and any lymph node metastases (4 weekly fractions of 9 Gy); and group 2 (n = 15) were treated the same but additionally received between two and six doses carboplatin at 300 mg m^?2 every 3 weeks. Median survival times for the two groups were 307 and 286 days, respectively (P > 0.05). In addition, carboplatin therapy did not significantly reduce the proportion of dogs dying due to metastases (three from group 1 and four from group 2). We found no evidence of a beneficial effect of carboplatin therapy over radiotherapy alone.     

Growth performance, energy, and nitrogen balance of weanling pigs fed a cereal-based diet supplemented with Chinese rhubarb

Forty Swiss Large White piglets of 4 weeks of age were used to determine the effect of dietary Chinese rhubarb on growth performance, as well as on energy and nitrogen metabolism by means of indirect respiration calorimetry studies. A cereal-based diet, supplemented with four different dosages of Chinese rhubarb (0.0%, 0.25%, 0.5%, 1%), was offered ad libitum to the piglets. Gaseous exchange was measured, and urine, faeces, and blood samples were taken. The addition of 0.25% dietary rhubarb increased feed intake (+32%) and daily weight gain (+67%) compared to the diet containing the greatest amount of rhubarb (1%). The piglets fed diet supplemented with 0.25% rhubarb digested and metabolised more energy and nitrogen relative to the animals of treatment 1%. As a consequence, the same group (0.25%) converted more energy and nitrogen into body protein than piglets receiving diet supplemented with 1% rhubarb. However, compared to the control group, the addition of 0.25% rhubarb to the diet resulted in not significantly alter growth performance, energy, and nitrogen metabolism of the animals.Blood parameters were not affected by the rhubarb supplementation. The dose-responding effect of Chinese rhubarb was reflected by the dry matter content of faecal samples. According to the laxative effect of higher doses of rhubarb, the addition of 1% rhubarb to the diet reduced dry matter content of faeces. This effect was well visible in practice, although not relevant in statistical terms. The addition of 0.5% dietary rhubarb had no relevant effect on growth performance or on energy and nitrogen metabolism of treated animals.     

The effects of ractopamine hydrochloride on lean carcass yields and pork quality characteristics

One hundred eighty barrows were evaluated to determine the effects of ractopamine hydrochloride (RAC) on lean carcass yields and pork quality. The pens were blocked by weight (six pens per block) with starting block weights of 69.0, 70.7, 73.8, 76.6, 78.4, and 84.3 kg. Pens within a block were assigned randomly to one of three RAC treatments so each treatment in a block was replicated twice. Treatments (as-fed basis) included control diet, 10 ppm of RAC added (R10), and 20 ppm of RAC added (R20) and ranged from 25 to 41 d depending on block. Pigs were slaughtered by blocks when block average live weights were 109 kg. Gain and feed efficiency were improved (P < 0.05) with increasing dietary concentrations of RAC, but feed intake did not differ (P > 0.05). Dressing percentage was higher (P < 0.05) for RAC-treated pigs. Subjective color, firmness, marbling scores, and Minolta L* reflection of the LM were not different (P > 0.05) among treatments. Carcass weights were heavier (P < 0.05) for pigs treated with RAC compared with control pigs and were higher for R20 than for R10. The RAC-fed pigs had greater (P < 0.05) yields (actual and percentage of HCW) of the following Institutional Meat Purchase Specification (IMPS) cuts than control pigs: trimmed, boneless ham (IMPS-402C and IMPS-402G), loin (IMPS-414), sirloin, and Boston butt (IMPS-406A). Pigs treated with RAC had a greater (P < 0.05) percentage of fat-free lean trimmings (IMPS-418) than did control pigs. Pigs treated with the R20 concentration had increased (P < 0.05) water-holding capacity compared with control pigs. Purge loss decreased linearly (P < 0.05) with increasing RAC compared with control for 14-d aged, non-enhanced loins. Warner-Bratzler shear (WBS) force values measured for nonenhanced chops were greater for RAC-treated pigs than for control pigs with a low dose response (P = 0.001). Enhanced chop (salt and phosphate injection) WBS values did not differ (P > 0.05) among dietary treatments. Trained sensory evaluation panel results for tenderness decreased in a low-dose plateau response fashion for nonenhanced chops (P = 0.004). Tenderness of enhanced chops decreased linearly (P = 0.04) with increasing RAC concentrations. No differences (P > 0.05) were found in juiciness or flavor of enhanced or nonenhanced chops. Feeding RAC to late-finishing swine resulted in faster growing, more efficient animals with increased boneless subprimal yields, and it had little effect on pork juiciness and flavor.     

A new single nucleotide polymorphism in CAPN1 extends the current tenderness marker test to include cattle of Bos indicus, Bos taurus, and crossbred descent

The three objectives of this study were to 1) test for the existence of beef tenderness markers in the CAPN1 gene segregating in Brahman cattle; 2) test existing CAPN1 tenderness markers in indicus-influenced crossbred cattle; and 3) produce a revised marker system for use in cattle of all subspecies backgrounds. Previously, two SNP in the CAPN1 gene have been described that could be used to guide selection in Bos taurus cattle (designated Markers 316 and 530), but neither marker segregates at high frequency in Brahman cattle. In this study, we examined three additional SNP in CAPN1 to determine whether variation in this gene could be associated with tenderness in a large, multisire American Brahman population. One marker (termed 4751) was associated with shear force on postmortem d 7 (P < 0.01), 14 (P = 0.015), and 21 (P < 0.001) in this population, demonstrating that genetic variation important for tenderness segregates in Bos indicus cattle at or near CAPN1. Marker 4751 also was associated with shear force (P < 0.01) in the same large, multisire population of cattle of strictly Bos taurus descent that was used to develop the previously reported SNP (referred to as the Germplasm Evaluation [GPE] Cycle 7 population), indicating the possibility that one marker could have wide applicability in cattle of all subspecies backgrounds. To test this hypothesis, Marker 4751 was tested in a third large, multisire cattle population of crossbred subspecies descent (including sire breeds of Brangus, Beefmaster, Bonsmara, Romosinuano, Hereford, and Angus referred to as the GPE Cycle 8 population). The highly significant association of Marker 4751 with shear force in this population (P < 0.001) confirms the usefulness of Marker 4751 in cattle of all subspecies backgrounds, including Bos taurus, Bos indicus, and crossbred descent. This wide applicability adds substantial value over previously released Markers 316 and 530. However, Marker 316, which had previously been shown to be associated with tenderness in the GPE Cycle 7 population, also was highly associated with shear force in the GPE Cycle 8 animals (P < 0.001). Thus, Marker 316 may continue to be useful in a variety of populations with a high percentage of Bos taurus backgrounds. An optimal marker strategy for CAPN1 in many cases will be to use both Markers 316 and 4751.