Effect of direct-fed microbial and antibiotic supplementation on gastrointestinal microflora, mucin histochemical characterization, and immune populations of weanling pigs

Direct-fed microbials (DFM) have the ability to alter gastrointestinal microflora, morphology and immunity. Denaturing gradient gel electrophoresis was used to analyze the effect of Lactobacillus brevis, Bacillus, and antibiotic supplementation on the gastrointestinal microbiota. Treatments were arranged in a 2 × 3 factorial arrangement with two levels of L. brevis supplementation and three diets (control, Bacillus, and antibiotic) fed during the nursery period. Microbial diversity of the gastrointestinal microbiota increased in response to any of the treatments containing L. brevis, Bacillus, or antibiotic compared to unsupplemented pigs. Pigs provided L. brevis and Bacillus in combination exhibited more bands of high G/C content than pigs provided only the antibiotic treatment. Supplementation with L. brevis resulted in a unique band that was identified as unculturable, low G/C content, gram positive bacteria. Furthermore, L. brevis increased pig body weight at the end of the nursery by 1.6 kg compared to pigs not provided L. brevis. L. brevis increased the number of acidic goblet cells present on villi within the duodenum and jejunum, and decreased the number of sulfated goblet cells, whereas Bacillus and antibiotic supplementation decreased the number of sulfated goblet cells on villi within the duodenum. Immunohistochemical evaluation revealed that L. brevis supplementation lowered the number of CD2⁺ cells, antigen presenting cells (MHCII⁺), and CD4⁺ T cells within jejunal villi. These data illustrate the potential for DFM to improve pig growth rate after weaning, as well as elicit alterations in the gut microbial community, mucin-producing goblet cells, and immune cells.     

The use of concentrated bovine serum albumin in canines.

In humans it has been estimated that for each 2.5 g L^–1 decrease in serum albumin, risk of death increases by 24–56%. Clinical impression suggests this may be similar in veterinary patients. Species‐specific albumin (plasma) is often unavailable and concentrated solutions are not. Our experience using 25% human serum albumin (HSA) in critically ill dogs suggests a positive effect (results submitted), however it is expensive. Bovine serum albumin (BSA) may be a more cost effective and readily available alternative. The purpose of this study was to assess the immediate and long‐term safety of an intravenous dose (500 mg kg^–1) of bovine albumin administered to healthy dogs. Ten mature dogs (eight males, two females, 28 ± 6 kg) were to receive BSA (250 mg mL^–1) twice (BSA1 and BSA2) with 14 days between treatments. Temperature, blood pressure, and pulse and respiration rate were continuously monitored to identify a reaction to BSA. All dogs received BSA1. One dog immediately developed mild urticaria and pruritus, otherwise the infusion was well tolerated. No immediate reaction was noted in the other nine dogs. Two dogs received BSA2. One dog developed a mild immediate reaction similar to that occurring with BSA1, and one dog (the dog immediately reacting to BSA1) developed a severe anaphylactic reaction. Due to these reactions, no other dogs received BSA2. During a two‐week observation of the remaining eight dogs given BSA1, five developed a mild or severe generalized type‐III hypersensitivity reaction. The dog experiencing a mild reaction during BSA2 administration also developed a generalized type‐III hypersensitivity reaction. Delayed reactions occurred 15 ± 2.7 days after BSA exposure. Three dogs did not develop a reaction. All reacting dogs recovered fully. The severity of reactions, and the number of dogs affected, suggests prior (natural) exposure and immunological sensitization to bovine albumin. Bovine serum albumin is not suitable for therapeutic use in dogs.     

The use of vascular access ports in nonanesthetized green iguanas (iguana iguana) to collect baseline arterial blood gas parameters.

The green iguana, Iguana iguana, is used as a model in reptile anesthesia research because of its size, availability, and the body of knowledge characterizing its physiology. Arterial blood gas values in nonanesthetized green iguanas have not been determined because of the technical difficulty involved. Vascular access port (VAP) placement to facilitate blood sampling has been described in other species, but not lacertilians. This abstract describes the technique for placement of VAPs and the values for arterial blood gas parameters in seven 1 kg adult green iguanas. Using sterile technique, a 1.5 cm incision was made on the lateral side of the neck. Blunt dissection ventral to the external jugular vein revealed the internal and external carotid arteries near their bifurcation. The catheter was inserted into the internal carotid artery and then guided to the common carotid artery. The other end of the catheter was tunneled below the skin to a subcutaneous location, caudal‐dorsal to the iSPSilateral scapula. The skin was closed and the port was flushed twice a week with heparinized saline. Post‐operatively, the VAPs were well tolerated by the iguanas. Difficulties included port disconnection (n = 1), inability to aspirate blood after a few weeks (n = 2), and infection (n = 1). The iguanas were breathing room air prior to and during blood collection. From the five functional VAPs, the blood pH, PCO₂, PO₂, HCO^‐₃, and BE (measured at 37 °C) were 7.45 ± 0.06; 37.5 ± 7.0 mm Hg, 99.0 ±16.6 mm Hg, 25.4 ± 2.5 mmol L^–1, and 1.5 ±2.4 mmol L^–1 respectively (mean ± SD). VAPs can be successfully used to facilitate collection of arterial blood gas samples in green iguanas. These values are similar to those reported for most mammalian species. This technique should facilitate research in anesthesiology and respiratory physiology of iguanas and other lacertilians.     

RT‐PCR based Tyrosine Kinase Display Profiling of Canine Melanoma: IGF‐1 Receptor as a Potential Therapeutic Target

Introduction:  There is a wealth of information available regarding tyrosine kinase (TK) expression in human cancer, however there is minimal information regarding the expression and function of TKs in canine melanoma, and no attempt has been made to systematically define the repertoire of TKs expressed. This study employed a molecular technique called RT‐PCR display to simultaneously evaluate the expression of up to 30 different TKs in a canine melanoma cell line.
Materials and Methods:  mRNA was extracted and reverse‐transcribed from the 17CM98 canine melanoma line, then subjected to PCR using degenerate primers coding for highly conserved regions which flank the kinase domains of many receptor and nonreceptor TKs. The resulting product was ligated into a plasmid vector and used to transform E. coli . Multiple colonies were isolated, and the cDNA inserts sequenced.
Results and Conclusions:  Sequencing 46 clones yielded canine homologs of IGF‐1R (50%), JAK1 (17%), PDGFR‐α(11%), FGFR1 (9%), Axl (7%), c‐Abl (4%), and PTK2 (2%). Interestingly, IGF‐1R, JAK1 and Axl were detected using a similar technique in human melanoma, supporting the cross‐species validity of this assay. Given the abundance of IGF‐1R clones, we sought to determine the biologic effect of rhIGF‐1 in 17CM98 cells. IGF‐1 stimulated IGF‐1R phosphorylation, cell proliferation and VEGF production in 17CM98, and protected the cells from serum starvation‐induced apoptosis. Expression of IGF‐1R mRNA was detected in 5 of 5 additional canine melanoma cell lines evaluated, suggesting that IGF‐1R expression may be common in canine melanoma cells and providing a novel target for future therapy.