Alternatives to antibiotics: a symposium on the challenges and solutions for animal production.

Antibiotics are one of the most important medical discoveries of the 20th century and will remain an essential tool for treating animal and human diseases in the 21st century. However, antibiotic resistance among bacterial pathogens and concerns over their extensive use in food animals has garnered global interest in limiting antibiotic use in animal agriculture. Yet, limiting the availability of medical interventions to prevent and control animal diseases on the farm will directly impact global food security and safety as well as animal and human health.

Characterization of bacteriophages virulent for Clostridium perfringens and identification of phage lytic enzymes as alternatives to antibiotics for potential control of the bacterium.

There has been a resurgent interest in the use of bacteriophages or their gene products to control bacterial pathogens as alternatives to currently used antibiotics. Clostridium perfringens is a gram-positive, spore-forming anaerobic bacterium that plays a significant role in human foodborne disease as well as non-foodborne human, animal, and avian diseases. Countries that have complied with the ban on antimicrobial growth promoters in feeds have reported increased incidences of C.

International shipping of fumonisins from maize extracts on C18 sorbent.

Fumonisins are mycotoxins found in maize. In developing countries, the resources required for analysis are often lacking, and the shipping of maize between countries can be difficult since the importation of plant materials requires permits/inspection to prevent the entry of pests that frequently infest maize. A simple, safe and legal method for shipping maize extracts to the USA was needed to conduct a survey of fumonisins in Central America.

Chemical and spectroscopic analysis of lignin in isolated flax fibers.

The chemistry of pure flax fibers, free of contaminating nonfiber components, has not been determined. Fibers from the center sections of the stem of seed and fiber flax (Linum usitatissium L.), which had been retted after soaking in water and removal of the epidermis by hand, underwent chemical and spectroscopic analysis.

Secretion of insulin-like growth factor (IGF)-I and -II and IGF binding proteins (IGFBPs) in fetal stromal-vascular (S-V) cell cultures obtained before and after the onset of adipogenesis in vivo.

The present study examined the influence of dexamethasone (DEX) treatment on preadipocyte differentiation and insulin-like growth factor binding protein (IGFBP) secretion in stromal-vascular (S-V) cell cultures established from subcutaneous adipose tissue obtained from nine 75 day and four 50 day pig fetuses. Cultures of S-V cells from four young pigs (5-7 days old) were also studied. Each fetal S-V cell culture represented 1 pool of S-V cells/dam.

Occurrence of Clostridium perfringens in the broiler chicken processing plant as determined by recovery in iron milk medium.

Over 30 years ago, Clostridium perfringens was reported as a contaminant of the processing plant and processed carcasses of broiler chickens. Poultry processing procedures and methods for detecting C. perfringens have changed since that time.

Chemical composition of components comprising bast tissue in flax.

Components from the bast region of flax (Linum usitatissium) were removed by hand from seed flax and fiber flax and analyzed by gas chromatography and mass spectrometry. Stems soaked in water were separated by hand into an outer layer, which consisted of epidermis with cuticle and parenchyma cells, and fiber bundles. Each of the two fractions were evaluated for chemical markers that could be used to predict the degree of retting and possibly fiber quality.

Determination of the incidence of Salmonella spp., Campylobacter jejuni, and Clostridium perfringens in wild birds near broiler chicken houses by sampling intestinal droppings.

Several methods were evaluated for collecting fecal and intestinal samples from wild birds found near broiler chicken houses. A few intestinal samples and cloacal swabs were obtained from European starlings and house sparrows. Most of the samples collected consisted of wild bird droppings found on or near the houses.

Colonization of the intestinal tract by Clostridium perfringens and fecal shedding in diet-stressed and unstressed broiler chickens.

Commercial broiler chicks were given a three-strain composite of bacitracin-resistant Clostridium perfringens by oral gavage and were sampled periodically to determine the dynamics of C. perfringens colonization of the intestinal tract of broiler chickens and fecal shedding. After gavage, the chicks were divided into two groups and placed in isolators, one group received a traditional corn-based diet, and the other group received the same diet supplemented with 50% rye to place the birds under dietary stress.

Fumonisin B1 and hydrolyzed fumonisin B1 (AP1) in tortillas and nixtamalized corn (Zea mays L.) from two different geographic locations in Guatemala.

Fumonisin B1 (FB1) is a common contaminant of corn worldwide and is responsible for several diseases of animals. In the preparation of tortillas, corn is treated with lime (producing nixtamal) that when heated hydrolyzes at least a portion of the FB1 to the aminopentol backbone (AP1), another known toxin. This study analyzed the amounts of FB1 and AP1 in tortillas and nixtamal from two communities in the central highlands of Guatemala where corn is a major dietary staple (Santa Maria de Jesus, Sacatepequez, and Patzicia, Chimaltenango).

Cecal carriage of Clostridium perfringens in broiler chickens given Mucosal Starter Culture.

Day-of-hatch broiler chicks housed in isolation units were each given, by oral gavage, 0.1 ml of Mucosal Starter Culture (MSC) or saline control. Each of the treated and control chicks was subsequently given a composite culture of three strains of bacitracin-resistant Clostridium perfringens (Cp) previously isolated from chickens with symptoms of necrotic enteritis.

The interaction of hydrocortisone and thyroxine during fetal adipose tissue differentiation: CCAAT enhancing binding protein expression and capillary cytodifferentiation.

Late-term fetal pigs from genetically obese dams have elevated levels of thyroid hormones and glucocorticoids, depressed levels of GH, larger fat cells and elevated lipogenesis than do fetal pigs from lean dams. We investigated the influence of elevated levels of thyroid hormones and glucocorticoids per se on adipose tissue traits by chronically treating hypophysectomized (hypox; d 70) fetal pigs between d 90 and 105 of gestation with either thyroxine (T4), hydrocortisone (HC), or the combination of T4 + HC. Treatment with T4 and T4 + HC increased serum T4 and IGF-I levels and enhanced skin and hair development.

Influence of thyroxine and hydrocortisone in vivo on porcine preadipocyte recruitment, development and expression of C/EBP binding proteins in fetal stromal vascular (S-V) cell cultures.

At 90 days of gestation hypophysectomized (hypox) porcine fetuses were treated with hydrocortisone (HC) or thyroxine (T4) and S-V cultures prepared from intact, treated and untreated hypox fetuses at 105 days of gestation. After 24 h, cultures were stained for the AD-3 antigen and the transcription factors, C/EBP alpha and delta. The proportion of preadipocytes (AD-3+) was doubled in cultures derived from HC treated hypox fetuses compared to cultures from intact, untreated and T4 treated hypox fetuses.

Extraction, quantification, and biological availability of fumonisin B1 incorporated into the Oregon test diet and fed to rainbow trout.

The purpose of this study was (i) to determine whether pure fumonisin B1 could be incorporated into, recovered, and detected by high-pressure liquid chromatographic analysis from the semipurified Oregon test diet (OTD) used in rainbow trout feeding studies, and (ii) to determine if the incorporated fumonisin B1 was biologically available using the change in free sphingoid bases in liver, kidney, and serum as a mechanism-based biomarker. The results indicate that fumonisin is not easily quantified in the OTD. Recoveries ranged from 12 to 81% of the calculated concentrations based on the fumonisin B1 added to the OTD.

In vitro attachment of Salmonella typhimurium to chicken cecal mucus: effect of cations and pretreatment with Lactobacillus spp. isolated from the intestinal tracts of chickens.

The attachment of radiolabeled Salmonella typhimurium 333/O cells to immobilized cecal mucus from specific-pathogen-free leghorn chickens was determined in the presence of D-mannose. The attachment of S. typhimurium was inhibited by the chelating agents EDTA and citrate and by lanthanum but was enhanced in the presence of the calcium, barium, and manganese divalent cations.

Growth factor regulation of insulin-like growth factor (IGF) binding proteins (IGFBP) and preadipocyte differentiation in porcine stromal-vascular cell cultures.

The influence of anti-IGF-1 and anti-transforming growth factor beta (TGF-beta) neutralizing antibodies on preadipocyte differentiation and secretion of IGFBPs was examined in serum free porcine stromal-vascular cultures. Cultures were stained for morphological analysis and conditioned media were collected for: TGF-beta determination by ELISA, IGF-1 by RIA, and IGFBP analysis by ligand blotting. After 6 d of treatment, anti-TGF-beta increased fat proportions by 2.

Evidence for a luteinizing hormone surge center in the hypothalamus of the pig.

Studies were conducted to determine whether there is an LH surge generator in the hypothalamus of the pig. In experiment 1, 157-day-old ovariectomized (OVX) gilts received 1.5 microg estradiol benzoate (EB)/kg BW i.

Immunocytochemical distribution of catecholamine-synthesizing neurons in the hypothalamus and pituitary gland of pigs: tyrosine hydroxylase and dopamine-beta-hydroxylase.

This study describes the distribution of catecholaminergic neurons in the hypothalamus and the pituitary gland of the domestic pig, Sus scrofa, an animal that is widely used as an experimental model of human physiology in addition to its worldwide agricultural importance. Hypothalamic catecholamine neurons were identified by immunocytochemical staining for the presence of the catecholamine synthesizing enzymes, tyrosine hydroxylase and dopamine-beta-hydroxylase. Tyrosine hydroxylase-immunoreactive perikarya were observed in the periventricular region throughout the extent of the third ventricle, the anterior and retrochiasmatic divisions of the supraoptic nucleus, the suprachiasmatic nucleus, the ventral and dorsolateral regions of the paraventricular nucleus and adjacent dorsal hypothalamus, the ventrolateral arcuate nucleus, and the posterior hypothalamus.

Immunocytochemical localization of the catecholamine-synthesizing enzymes, tyrosine hydroxylase and dopamine-beta-hydroxylase, in the hypothalamus of cattle.

Immunocytochemical staining for the presence of catecholamine synthesizing enzymes, tyrosine hydroxylase and dopamine beta-hydroxylase, was used to characterize the regional distribution of catecholaminergic neurons in the hypothalamus and adjacent areas of domestic cattle, Bos taurus. In steers, heifers and cows, tyrosine hydroxylase-immunoreactive perikarya was located throughout periventricular regions of the third cerebral ventricle, in both anterior and retrochiasmatic divisions of the supraoptic nucleus, suprachiasmatic nucleus, and ventral and dorsolateral regions of the paraventricular nucleus, dorsal hypothalamus, ventrolateral aspects of the arcuate nucleus, along the ventral hypothalamic surface between the median eminence and optic tract, and in the posterior hypothalamus. Immunostained perikarya ranged from small (10-20 microns, parvicellular) to large (30-50 microns, magnocellular) and were of multiple shapes: round, triangular, fusiform or multipolar, often with 2-5 processes of branched arborization.

Catecholaminergic region A15 in the bovine and porcine hypothalamus.

Magnocellular perikarya within the retrochiasmatic division of the supraoptic nucleus of bovine and porcine hypothalami were immunoreactive (ir) with antiserum against tyrosine hydroxylase (TH), but not dopamine-beta-hydroxylase (DBH). Few cells in this region were also immunoreactive for vasopressin (VP) or oxytocin (OT). In contrast, the main division of the supraoptic nucleus contained numerous perikarya immunoreactive for VP and OT, but not TH nor DBH.

Opioid modulation of gonadotropin releasing hormone release from the hypothalamic preoptic area in the pig.

Two experiments (Exp) were conducted to examine in vitro the release of gonadotropin releasing hormone (GnRH) from the hypothalamus after treatment with naloxone (NAL) or morphine (MOR). In Exp 1, hypothalamic-preoptic area (HYP-POA) collected from 3 market weight gilts at sacrifice and sagittally halved were perifused for 90 min prior to a 10 min pulse of morphine (MOR; 4.5 x 10(-6) M) followed by NAL (3.

Altered colonizing ability for the ceca of broiler chicks by lipopolysaccharide-deficient mutants of Salmonella typhimurium.

Salmonella typhimurium strain 3333/O was used to assess the role of bacterial lipopolysaccharide (LPS) in intestinal colonization of broiler chicks by salmonellae. LPS-defective TnPhoA mutants of this strain were isolated. The sensitivities of the mutants to smooth and rough phages and LPS banding patterns in sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated a defect in the polysaccharide side chain of the LPS molecule.

Cyclic hydroxamic acid accumulation in corn seedlings exposed to reduced water potentials before, during, and after germination.

Cyclic hydroxamic acids are innate compounds associated with pest resistance in several grass species. The major cyclic hydroxamic acids of com, 2,4-dihydroxy-7-methoxy-2H-1,4-benzoxazin-3-one (DIMBOA) and 2,4-dihydroxy-3H-1,4-benzoxazin-3-one (DIBOA), were measured in seedlings after exposure to various water stress treatments. Both DIMBOA and DIBOA were found in greater quantities in plants experiencing a water deficit stress than in nonstressed plants.

Characterization of Salmonella california and S. typhimurium strains with reduced ability to colonize the intestinal tract of broiler chicks.

This study determined the ability of eight strains of Salmonella and their agarsubcultured variants to colonize the intestinal tract of broiler chicks. Nalidixic-acid (NAL)-resistant and streptomycin-resistant subcultured strains (S. california 1989/A and S.