Effects of stress associated with weaning on the adaptive immune system in pigs

This study was designed to investigate the effects of weaning age on specific components of the adaptive immune system in pigs. Twenty-three crossbred pigs were randomly assigned to 1 of 3 treatments: weaning at 14 (14D, n = 8), 21 (21D, n = 7), or 28 (28D, n = 8) d of age. Peripheral blood samples, obtained when pigs were 13, 15, 20, 22, 27, 29, and 35 d of age, were analyzed for peripheral blood cell percentages and concentrations of neutrophils, lymphocytes, T cell subsets, mature B cells, and plasma cortisol concentrations. For each of the 3 groups, weaning increased plasma cortisol concentrations (P < 0.001) and reduced BW percentage change (P < 0.017). Lymphocyte concentrations displayed a treatment effect for the 14D (P = 0.074) and 28D (P = 0.014) groups. Albeit inconsistent, lymphocyte concentrations were less in weaned pigs on the day after weaning than in pigs remaining on the sow or weaned at a younger age. Specifically, mature B cells (CD21(+)) and CD4(+)CD8(+) cells decreased (P < 0.05) after weaning at 28 d of age. Other differences occurred among treatments; however, the differences apparently were not associated with weaning. Based upon the immunological measures used in the present study, there was not an explicit benefit to the adaptive immune system for any weaning age. Early weaning did not negatively affect the adaptive immunological competence of pigs as determined by changes in populations of immune cells.     

Heterosis and recombination effects on pig reproductive traits

The objective was to estimate breed, heterosis, and recombination effects on pig reproductive traits in two different four-breed composite populations. Breeds included Yorkshire, Landrace, Large White, and Chester White in Exp. 1 and Duroc, Hampshire, Pietrain, and Spot in Exp. 2. Data were recorded on purebred pigs, two-breed cross pigs, and pigs from generations F1 through F6, where F1 pigs were the first generation of a four-breed cross. Litter traits were considered a trait of the gilt. There were 868 first parity litters in Exp. 1 and 865 in Exp. 2. Direct heterosis significantly increased sow weight at 110 d of gestation and litter weight at 14 and 28 d (weaning) in both experiments. Direct heterosis significantly increased number of nipples, weight at puberty, lactation weight loss, litter size, and litter birth weight in Exp. 2. Gestation length in Exp. 1 and age at puberty in Exp. 1 and Exp. 2 were significantly decreased by direct heterosis. Maternal heterosis significantly increased age at puberty in Exp. 2 and decreased sow weight at 110 d of gestation in Exp. 1. Recombination significantly increased sow weight at 110 d of gestation and tended to increase total number born and litter birth weight in Exp. 1. Recombination significantly decreased age at puberty in Exp. 2. Litter heterosis significantly increased number of pigs at 14 and 28 d; litter weights at birth, 14, and 28 d; and tended to increase lactation weight loss in Exp. 1. Litter heterosis decreased litter size in Exp. 2. Maternal heterosis and recombination effects had a sampling correlation of -0.97 in Exp. 1 and -0.91 in Exp. 2 for number of fully formed pigs. Therefore, maternal heterosis and recombination effects were summed, and their net effect was tested. This net effect tended to increase number of nipples, lactation weight loss, and litter birth weight and significantly increased number of fully formed pigs in Exp. 1. Direct, maternal, and litter heterosis and recombination effects significantly influenced reproductive traits.     

Teaching of veterinary parasitology: the Italian perspective

The curriculum in veterinary medicine in Italy is undergoing important changes, as in the rest of Europe. The 2001 fall semester will mark the beginning of a new format for the degree in veterinary medicine and these changes will obviously affect the teaching of veterinary parasitology. In Italy, veterinary parasitology is usually taught in the third year with a disciplinary approach, similar to that described by Euzéby [Vet. Parasitol. 64 (1996) 21] and Eckert [Vet. Parasitol. 88 (2000) 117]. Approximately 90 h of lectures and 40 h of laboratory are offered and are usually divided into parasitology, followed by parasitic diseases. A more problem-oriented approach to parasitology is offered to fifth-year students within several professional routes (large animal medicine, small animal medicine, hygiene and food safety, etc.), amounting to approximately 15-60 h per student. Indeed, in the last year of study, there are less students and it is possible to present clinical cases and orient the students towards team work and critical discussion. This new curriculum guarantees a reduction in the number of lecture hours and an increase in both laboratory work and personal study, as suggested by the guidelines of the European association of establishment for veterinary education (EAEVE).     

Spectrophotometric assessment of peritoneal fluid haemoglobin in colic horses: an aid to selecting medical vs. surgical treatment

In a case-control study in colic horses the ability of spectrophotometric measurement of the haemoglobin concentration in the peritoneal fluid supernatant and visual assessment of the colour of peritoneal fluid supernatant to differentiate between surgical and medical treatment of colic was assessed. Based on previous studies, which have found anda association between peritoneal fluid colour and the kind of treatment required, our hypothesis was that the peritoneal fluid haemoglobin concentration would be higher in horses requiring surgical intervention than in horses amenable to medical treatment. Seventy-four horses admitted to a teaching hospital were included. Thirty-five horses were classified as requiring surgery and 39 medical treatment. Logistic regression revealed a significant (P < 0.0001) association between the haemoglobin concentration measured with the spectrophotometer and the need for surgical treatment. Odds ratio for an increase in haemoglobin concentration of 0.01 mmol/l was 6.4, which means that the odds for 'need for surgical treatment' increased when peritoneal fluid haemoglobin concentration increased. When used as a diagnostic test with a threshold of 0.01 mmol/l haemoglobin for selecting surgical vs. medical treatment, sensitivity was 80% and specificity 82%, whereas simple visual assessment had a sensitivity of only 51% and a specificity of 95%.     

Experimental airborne transmission of porcine reproductive and respiratory syndrome virus and Bordetella bronchiseptica

Experiments were designed to determine if porcine reproductive and respiratory syndrome virus (PRRSV) or Bordetella bronchiseptica could be transmitted through indirect airborne contact. Three principal pigs were infected with PRRSV, B. bronchiseptica or both. Five days after the principal pigs were challenged, the three principal pigs and one direct-contact pig were placed into one isolation tent together, and three indirect-contact pigs were placed into another isolation tent which received its air supply from the first isolation tent. Airborne transmission of B. bronchiseptica occurred in 5/5 trials where B. bronchiseptica was the only agent used, and in 3/5 trials where the principal pigs were coinfected with both agents. Airborne transmission of PRRSV occurred in 4/5 trials where PRRSV was the only agent used, and in 2/5 trials where the principal pigs were coinfected with both agents. Thus, airborne transmission of both agents over short distances, such as within a barn, is probable.     

Results of thyroid function tests and concentrations of plasma proteins in dogs administered etodolac

OBJECTIVE: To determine the effects of etodolac administration on results of thyroid function tests and concentrations of plasma proteins in clinically normal dogs. Animals: 19 healthy random-source mixed-breed dogs. PROCEDURE: Blood samples for measurement of serum thyroxine (T4), 3,5,3'-triiodothyronine (T3), free T4 (fT4), and endogenous canine thyroid stimulating hormone (cTSH) were measured twice before as well as on days 14 and 28 of etodolac administration (mean dosage, 13.7 mg/kg, PO, q 24 h). Plasma total protein, albumin, and globulin concentrations and serum osmolality were measured once before as well as on days 14 and 28 of etodolac administration. RESULTS: Etodolac administration did not significantly affect serum T4, T3, fT4, or cTSH concentrations or serum osmolality. Significant decreases in plasma total protein, albumin, and globulin concentrations were detected on days 14 and 28 of administration. CONCLUSIONS AND CLINICAL RELEVANCE: Results of thyroid function tests are not altered when etodolac is administered for up to 4 weeks. Therefore, interpretation of results of these tests should accurately reflect thyroid function during etodolac treatment. Plasma total protein, albumin, or globulin concentrations that are less than the respective reference range in a dog administered etodolac for > or = 2 weeks may be an effect of treatment rather than an unrelated disease process. A decrease in plasma protein concentrations may reflect subclinical injury of the gastrointestinal tract.     

Effects of virginiamycin and monensin plus tylosin on ruminal protein metabolism in steers fed corn-based finishing diets with or without wet corn gluten feed

Six ruminally cannulated steers (345 +/- 20 kg initial BW) were used in a 6 x 6 Latin square to evaluate effects of diet and antibiotics on ruminal protein metabolism. Two diets and three antibiotic treatments were arranged factorially. One diet contained (DM basis) 72% dry-rolled corn, 12% soybean meal, 10% alfalfa hay, and 4% molasses (SBM), and the other contained 63% dry-rolled corn, 30% wet corn gluten feed, and 5% alfalfa hay (WCGF). Antibiotic treatments included control, virginiamycin (175 mg/d; VM), and monensin/tylosin (250 and 100 mg/d, respectively; MT). Steers were fed at 12-h intervals at a rate of 2.4% of empty BW daily. Each period included 18 d of adaptation and 3 d of ruminal fluid collections. Samples were collected at 0, 2, 4, 6, 8, and 10 h after the morning feeding on d 19 and 20. On d 21, rumens were dosed 2 h after the morning feeding with 350 g of solubilized casein to evaluate in vivo ruminal protease and deaminase activities. Ruminal fluid samples were collected 1, 2, 3, 4, and 6 h after the casein dose. On d 19 and 20, antibiotics had no effect on ruminal pH or concentrations of VFA, lactate, ammonia, ciliated protozoa, alpha-amino nitrogen (AAN), or peptide N, but VM reduced (P < 0.01) the concentration of isovalerate compared to MT and control. After casein dosing (d 21), peptide N concentration was unaffected by antibiotics, but AAN were higher (P < 0.01) for VM than MT and control. Relative to MT and control, VM reduced ruminal isovalerate (P = 0.05) and increased ruminal propionate (P < 0.01) on d 21. Ruminal pH was lower (P < 0.01) in steers fed SBM than in steers fed WCGF, but lactate concentrations were unaffected by diet. Steers fed SBM had higher (P < 0.05) ruminal concentrations of total VFA and propionate. Ammonia concentrations were lower before feeding and higher after feeding for steers fed WCGF (P < 0.01). Steers fed WCGF had higher counts of total ciliated protozoa than steers fed SBM (P < 0.05) due to greater Entodinium sp. (P < 0.05). Steers fed WCGF had higher (P < 0.01) ruminal AAN and peptide N concentrations than those fed SBM on d 19 and 20. After casein dosing, ruminal peptide N concentrations were similar, but AAN were lower (P < 0.01) for WCGF than SBM. Overall, VM appeared to depress ruminal deaminase activity, and MT had minimal effects on ruminal fermentation products. The protein in WCGF appeared to be more readily degradable than that in SBM.     

Avascular necrosis of the femoral heads in a red panda (Ailurus fulgens fulgens): possible Legg-Calve-Perthes disease.

A 17-mo-old captive-born female red panda (Ailurus fulgens fulgens) presented with a sudden onset of lameness in its left hind leg was diagnosed radiographically as having possible severe, bilateral Legg-Calve-Perthes disease with fracture of the great trochanter of the left femur. Surgical repair of the fracture was performed using pins and a tension band wire through a lateral approach to the hip. This is the first case reported at Madrid Zoo-Aquarium, where 63 individuals have been bred over 15 yr.     

Myopathy in brown pelicans (Pelicanus occidentalis) associated with rancid feed

Three adult brown pelicans (Pelicanus occidentalis) were observed to be weak, anorexic and unresponsive to antibiotics, anti-inflammatory drugs, vitamins including vitamin E, and steroids. Blood chemistry revealed high activities of aspartate aminotransferase, creatinine kinase and lactate dehydrogenase. Radiographs of the birds' leg muscles revealed multiple opacities suggestive of calcification; the gross lesions included white streaks in the leg, wing, and heart muscles, and the microscopical lesions consisted of various degrees of degeneration and necrosis characterised by eosinophilia, variations in fibre size, loss of striations, myolysis, mineralisation, and proliferation of mononuclear cells in the skeletal muscles and the myocardium. The levels of heavy metals, selenium and vitamin E in the birds' livers were not abnormal. The level of peroxide in their diet of capelin fish was high, 69 meq/kg, (normal <20 meq/kg) consistent with rancid feed, and the level of vitamin E was very low, 0.5 iu/kg (normal 20 to 30 iu/kg). It was concluded that the myopathy was probably caused by vitamin E deficiency due to feeding the pelicans a rancid diet.     

Pituitary effects of steroid hormones on secretion of follicle-stimulating hormone and luteinizing hormone

Steroid hormones have a profound influence on the secretion of the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH). These effects can occur as a result of steroid hormones modifying the secretion of gonadotropin-releasing hormone (GnRH) from the hypothalamus, or a direct effect of steroid hormones on gonadotropin secreting cells in the anterior pituitary gland. With respect to the latter, we have shown that estradiol increases pituitary sensitivity to GnRH by stimulating an increase in expression of the gene encoding the GnRH receptor. Since an estrogen response element (ERE) has not been identified in the GnRH receptor gene, this effect appears to be mediated by estradiol stimulating production of a yet to be identified factor that in turn enhances expression of the GnRH receptor gene. However, the importance of estradiol for enhancing pituitary sensitivity to GnRH during the periovulatory period is questioned because an increase in mRNA for the GnRH receptor precedes the pre-ovulatory rise in circulating concentrations of estradiol. In fact, it appears that the enhanced pituitary sensitivity during the periovulatory period may occur as a result of a decrease in concentrations of progesterone rather than due to an increase in concentrations of estradiol. Estradiol also is capable of altering secretion of FSH and LH in the absence of GnRH. In a recent study utilizing cultured pituitary cells from anestrous ewes, we demonstrated that estradiol induced a dose-dependent increase in secretion of LH, but resulted in a dose-dependent decrease in the secretion of FSH. We hypothesized that the discordant effects on secretion of LH and FSH might arise from estradiol altering the production of some of the intrapituitary factors involved in synthesis and secretion of FSH. To examine this hypothesis, we measured amounts of mRNA for activin B (a factor known to stimulate synthesis of FSH) and follistatin (an activin-binding protein). We found no change in the mRNA for follistatin after treatment of pituitary cells with estradiol, but noted a decrease in the amount of mRNA for activin B. Thus, the inhibitory effect of estradiol on secretion of FSH appears to be mediated by its ability to suppress the expression of the gene encoding activin.