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SUMMARY The nursery industry pasteurizes soil with steam and quicklime to reduce plant pathogens. The mechanism of action for quicklime is the resulting exothermic reaction that occurs when the chemical interacts with water and its ability to increase pH levels. These treatments may also reduce pathogens in a commercial poultry house. In this study, a steam sterilization cart simulated conditions used by the nursery industry to treat litter inoculated with Salmonella enterica serovar Typhimurium. A homogenized sample of litter was exposed to steam for 0, 5, 30, or 120 min. Quicklime was used at concentrations of 0 (control), 2.5, 5.0, or 10.0%. All steam treatments, with or without quicklime, significantly reduced Salmonella Typhimurium colonization by at least 3 orders of magnitude. Significant reductions were also observed in the treatments with quicklime alone. Both the steam and the quicklime treatments often reduced colonization to undetectable levels, even when samples were enriched. Therefore, we demonstrated 2 novel techniques for reducing Salmonella Typhimurium in poultry litter. Soil pasteurization potentially offers an environmentally sound means of reducing the pathogens present in used poultry litter.

SUMMARY Two consecutive experiments were conducted to evaluate the influence of diet on oocyst shedding and lesion development in replacement broiler breeders of 2 different genetic lines after coccidiosis vaccination. The first experiment was conducted on fresh pine shavings as the litter source, whereas the second trial was conducted on the used litter from the first experiment. Dietary formulation was based on either breeder-specific recommendations or formulations of a broiler integrator. Fecal samples were collected every other day beginning on d 6 and continuing throughout the experiment to determine oocyst shedding. Lesion assessment was performed at selected time points in both experiments to evaluate gross and microscopic intestinal lesions. In experiment 1, multiple peaks in oocyst output were observed in both genetic lines, with the first peak occurring at approximately 16 to 18 d after placement. This peak tended to have the highest observed magnitude and corresponded with the highest level of intestinal lesions observed during experiment 1. Oocyst cycling in experiment 2 followed a somewhat different pattern. Peaks were delayed and at a lower magnitude. Dietary interactions were observed in both experiments, with amount and duration of oocyst shedding and severity of lesion development being influenced by diet in both male and female genetic lines. Increased lesion severity was observed in both genetic lines fed the integrator diet as compared with the breeder-recommended diet; however, the relationship of shedding and diet was dependent on genetic line and sex. Therefore, nutrient density affects oocyst cycling and lesion development during coccidiosis vaccination in replacement broiler breeders.

SUMMARY Modern broilers grow much faster and more efficiently than their predecessors. Because of the rapid growth rates of broilers, particular attention must be given to the skeletal development of the bird. Calcium formate (CaFo) has been used as a calcium source in animal diets in the European Union for many years. The objective of this study was to evaluate CaFo in broiler diets as an alternative source of calcium. Four experimental groups (0.0, 0.5, 1.0, and 1.5% CaFo) were evaluated, with 10 replicate pens per treatment. Variables measured included BW, FCR, tibia weight, bone ash percentage, tibia breaking strength, and gut morphology. Many of the parameters measured were statistically similar to the calcium carbonate control treatment. However, the 1.0% CaFo treatment significantly increased tibia breaking strength and duodenal villus height when compared with the other treatments at the completion of grow out. Therefore, CaFo can serve as an alternative calcium source in broiler diets and may significantly improve skeletal development.

SUMMARY A collection of members of the poultry industry and allied industries were asked to provide their opinions and comments regarding the enhancement of extension resources to benefit the industry. Topics that were discussed included the effectiveness of industry associations’ support and influence on land grant universities’ teaching and research priorities, the possibility of a land grant university or department having all resources needed to meet industry needs, what barriers exist against forming a “center of excellence,” where priorities of the University Extension Service should lie and why, what the best method of delivering information regarding biosecurity practices to relevant audiences is, and how costs incurred by specialists should be handled in relation to independent consultants.

The current experiment was conducted to determine the effect of mycotoxin-contaminated diets with aflatoxin (AFLA) and deoxynivalenol (DON) and dietary inclusion of deactivation compound on layer hen performance during a 10-wk trial. The experimental design consisted of a 4 × 2 factorial with 4 toxin levels: control, low (0.5 mg/kg AFLA + 1.0 mg/kg DON), medium (1.5 mg/kg AFLA + 1.5 mg/kg DON), and high (2.0 mg/kg AFLA + 2.0 mg/kg DON) with or without the inclusion of deactivation compound. Three hundred eighty-four 25-wk-old laying hens were randomly assigned to 1 of the 8 treatment groups. Birds were fed contaminated diets for a 6-wk phase of toxin administration followed by a 4-wk recovery phase, when all birds were fed mycotoxin-free diets. Twelve hens from each treatment were subjected to necropsy following each phase. Relative liver and kidney weights were increased (P < 0.05) at the medium and high toxin levels following the toxin phase, but the deactivation compound reduced (P < 0.05) relative liver and kidney weights following the recovery period. The high toxin level decreased (P < 0.05) feed consumption and egg production during the toxin period, whereas the deactivation compound increased (P < 0.05) egg production during the first 2 wk of the toxin phase. Egg weights were reduced (P < 0.05) in hens fed medium and high levels of toxin. An interaction existed between toxin level and deactivation compound inclusion with regard to feed conversion (g of feed/g of egg). High inclusion level of toxins increased feed conversion compared with the control diet, whereas deactivation compound inclusion reduced feed conversion to a level comparable with the control. These data indicate that deactivation compound can reduce or eliminate adverse effects of mycotoxicoses in peak-performing laying hens.

A procedure for the isolation and primary culture of epithelial cells from the mucosal region of the upper ileum in the chicken is described. When cells are isolated using this technique, normal in vivo-like morphology and viability are obtained and can be maintained in short-term as well as primary cultures exceeding 3 wk. This procedure for isolation of enterocytes is easily performed and provides access to primary mucosal epithelial cell cultures for pathologic and physiologic investigations of isolated chicken enterocyte function.

Interferon-gamma (IFNgamma) has been demonstrated to have potent stimulatory effects on parameters of cell-mediated immunity in chickens (11). Protection of neonatal leghorn chickens against infection by invasive salmonellae has been associated with enhanced cell-mediated indices of immunity (5). The present investigation evaluated the effect of recombinant-turkey (rt) IFN-gamma on protection of neonatal leghorn chicks from Salmonella enteritidis (SE) organ invasion after experimental challenge in three experiments. In Expt. 1, intraperitoneal (i.p.) administration of 25 microg rtIFNgamma per chick 30 min prior to per os SE challenge resulted in a 35% reduction (P0.01) in SE organ invasion when compared with control (vehicle injected) chicks 24 hr post-SE challenge. However, i.p. administration of 2.5 microg rtIFNy per chick was not efficacious in reducing SE organ invasion. In Expt. 2 and Expt. 3, i.p. administration of 13.75 microg rtIFNgamma per chick 30 min prior to per os SE challenge resulted in significant reductions of 38.4% (P0.025) and 31.58% (P0.01), respectively, in SE organ invasion as compared with control chicks 24 hr post-SE challenge. Administration of 2.5 or 25 microg rtIFNgamma per chick i.p. had no effect on SE organ invasion in either Expt. 2 or Expt. 3 24 hr post-SE challenge. Additionally, i.p. administration of rtIFNgamma 30 min prior to SE challenge in Expt. 2 and Expt. 3 was not associated with protection against SE organ invasion when organ culture was performed 72 hr postchallenge. Further, the oral administration of 25 microg rtIFNgamma per chick was not efficacious in conferring protection against SE organ invasion at 24 or 72 hr postchallenge when this route of administration was evaluated in Expt. 2. Similarly, the subcutaneous administration of a potential repository injection of 13.75 or 25 microg rtIFNgamma per chick did not protect chicks against SE organ invasion when evaluated 72 hr postchallenge. These data indicate a potential acute immunostimulatory activity of rtIFNgamma in chickens experimentally challenged with SE. Further, these experiments, although preliminary, are suggestive of the potential involvement of IFNgamma in cell-mediated or innate mechanisms of protective immunity against salmonellosis in chickens.

In our laboratory, we have often had difficulty infecting neonatal chickens with invasive salmonellae when ambient temperatures exceed 30 C. We hypothesized that this increased resistance in chicks during warmer months may be associated with heat stress-associated maternal factors. Presently, single-comb white leghorn hens were separated into a non-heat-stressed group, reared under temperatures from approximately 10 to 24 C, and a heat-stressed group, in which environmental temperature was incrementally elevated to near 37 C and maintained for the duration of the 13-wk study. For Expt. 1, eggs from heat-stressed or control hens, collected on days 8-14 of the study, were pooled respective to treatment and incubated. At the time of egg collection, mean hen-day egg production was 51.83% or 65% for heat-stressed or control hens, respectively. On day of hatch, progeny from hens in each group were orally challenged with 0.9 x 10(4) colony-forming units (CFU) Salmonella enteritidis (SE). Rates of SE organ invasion of 97.3% or 94.4% were obtained in progeny from heat-stressed or control hens, respectively. In Expt. 2, eggs from heat-stressed or control hens from days 30-42 of the study were collected and pooled by treatment for incubation. Mean hen-day egg production was 46.5% or 72.85% for heat-stressed or control hens, respectively. On day of hatch, progeny were orally challenged with either 2.2 x 10(3) or 2.2 x 10(4) CFU SE. A 100% incidence in SE organ invasion was observed in all groups. In Expt. 3, eggs were collected from days 43 through 56 of the study. Mean hen-day egg production was 19.8% or 76.8% for heat-stressed or control hens, respectively. On day of hatch, progeny were orally challenged with 2 x 10(3) CFU SE. Rates of SE organ invasion of 95.8% or 95.6% were obtained in progeny from heat-stressed or control hens, respectively. These data suggest that factors other than elevated temperature may be responsible for seasonal resistance to invasive salmonellae infection in neonatal chickens observed in our laboratory during warmer months in Texas.

In this study we tested the hypothesis that the frequency of Salmonella isolation from protective foot covers worn in individual broiler production houses would compare favorably to isolation rates obtained from conventional drag-swab methods. Salmonella was detected with equal frequency from protective foot covers and drag-swab assemblies on nine individual broiler farms over three separate sampling periods. Salmonella was detected in 13 of a total 27 individual samplings by culturing the protective foot covers, whereas positive detections occurred in 16 of a total 27 samplings when using the drag-swab method. Of the total number of houses identified as positive, these frequencies were unaltered when evaluated against the flock status of each farm at the time of sampling. Both methods were equally as likely to detect Salmonella when houses were either vacant (awaiting the placement of the next flock) or occupied (currently housing chickens of any age). In addition to highlighting the development of a potential new Salmonella monitoring technique, this study reinforces our current understanding regarding the importance of stringent biosecurity practices on poultry farms.

The Army has proposed using a liquid propellant (XM46) composed of hydroxylammonium nitrate (HAN) and triethanolammonium nitrate (TEAN) in its Advanced Field Artillery System. This study was undertaken to determine the potential threat to the unborn fetus should female Army personnel become exposed to this compound during pregnancy. Timed pregnant rats (Crl:CD Charles River Laboratories, Inc.) were purchased on day 4 of pregnancy and divided into a control and four dose groups of 25-28 animals each. Animals were dosed orally with XM46 on days 6-15 of pregnancy at the rate of 0.0, 162.5, 325 and 650 mg kg-1 body wt day-1. Cesarean section was performed on gestation day 20. Maternal body weight was significantly reduced in the 650 mg kg-1 day-1 dose group on days 5-20 of pregnancy. Likewise, maternal food consumption was significantly reduced in the high-dose animals during the dosing period. There were no exposure-related differences in fetal weight, number, sex or frequency of malformations observed in fetuses between control and treated dams. The results of this study indicate that XM46 is not a teratogen in the rat.

Much previously published research has focused on the role of cecal and intestinal Salmonella contamination of poultry carcasses within commercial processing plants. Presently, we have evaluated the persistence of experimentally inoculated Salmonella enteritidis in the crops and ceca of com­ mercial broiler chickens during the last week of growth (Weeks 6 to 7) and the presence of crop and cecal Salmonella in 7-wk-old broilers in a commercial processing plant. When broilers were inoculated with 1 x 106 cfu S. enteritidis at 6 wk of age by oral gavage, the incidence of crop and cecal contamination was equivalent 2 d after challenge (30%), with only 1 of 29 crops contaminated and 0 of 29 ceca contaminated at 7 d following challenge. When broilers were inoculated with 1 x 108 cfu S. enteritidis at 6 wk of age by oral gavage, 2 d after challenge the crops and ceca were observed to be 57 and 67% positive for S. enteritidis, respectively. Seven days after inoculation with 1 x 108 S. enteritidis, the crops and ceca were 37 and 57% positive, respectively, for the challenge organism. At a commercial broiler processing plant, 286 of 550 crops from three flocks were SaZmoneHa-positive, whereas only 73 of 500 ceca from these flocks were contaminated. Furthermore, data from this plant indicated that the crops were far more likely to rupture than ceca (86-fold) during processing, increasing the possibility of carcass contamination with Salmonella derived from crop contents. The results of these studies suggest that the crop may serve as a source of carcass contamination with Salmonella within some processing plants. (Key words: Salmonella, chicken, contamination, crop, ceca)

The consistency and persistence of isolation of specific serotypes of Salmonella were evaluated on a 31-farm broiler complex following four complete sampling periods. A total of 25 different serotypes were isolated, with multiple serotypes and were frequently isolated simultaneously from individual farms. When the serotypes recovered from individual farms were further examined, common serotypes were isolated from individual farms on only seven occasions. Furthermore, on only five occasions were multiple serotypes recovered from individual farms on consecutive samplings. A casual association of common serotype isolations among farms with similar flock placement dates was observed in one sampling period. These results indicate little predictability or consistency of Salmonella serotype isolation on individual farms over time.

The results of four independent complete drag-swab samplings of a 31-farm broiler-production complex are described. Samplings of vacant poultry farms (i.e., between flocks) and occupied farms (i.e., containing chickens) were completed in four 3-day intervals beginning in July 1992 and ending in May 1993. During the first two sampling periods, two drag-swab assemblies were dragged through each individual house and pooled into one sample to evaluate overall incidence of Salmonella detection among vacant and occupied houses. During the second two sampling periods, four drag-swab assemblies were dragged through houses to evaluate frequency of Salmonella detection on individual assemblies within each house. Over the four sampling periods, mean isolation frequencies were 42.2% for vacant poultry farms and 76.2% for occupied poultry farms. When four assemblies were dragged in vacant houses and cultured separately, the probability of detecting salmonellae contamination increased with increasing numbers of assemblies, indicating that multiple drag-swab assemblies should be used for sampling either vacant or occupied broiler houses for the presence of Salmonella. On vacant farms, 89.5% of the total isolations occurred in only one house of two-house farms; the remaining 10.5% of farms were positive in both houses. Salmonella isolation from occupied farms occurred in 54.2% of the samplings in only one house, whereas 45.8% of occupied farms were positive in both houses. These data show a higher frequency of Salmonella isolation on multiple swabs in occupied poultry houses, possibly indicating a quantitatively greater presence of Salmonella in these houses.

A tractable method is presented for separating vibronic and static effects, which does not require extensive vibrational analysis of each molecule. The parameters so obtained can be expressed in terms of explicit matrix elements for a computation using only equilibrium position geometry and orbitals. The behavior of these vibronic quantities can provide an extremely sensitive means for studying the effects of substitution on the transition density matrix. This paper has been designed with sufficient flexibility in both the phenomenological and computational formalism to indicate how results of one procedure suggest appropriate modifications in the other. Benzene and its derivatives provide a fitting example for summarizing the procedure.

A general method for correlating data from CD and MCD spectra is formulated. The origin dependence of the MCD terms is resolved by minimization of appropriate terms in the Lagrangian density expression. Approximate summation techniques are developed for magnetic and natural optical activity. The salient features of the MCD spectra of benzene derivatives are analyzed. The observed opposite signed magnetic rotational strengths of (o,p)‐ and m‐directors is accounted for by a variation calculation which includes electron donor and acceptor wavefunctions based on occupied and unoccupied substituent orbitals. The uniqueness of the alternating signed benzene spectrum as compared with most hexasubstituted derivatives of D6h symmetry is rationalized on the basis of the vibrational modes of E2g symmetry for carbon‐carbon bond stretching and bending. The importance of comparable vibronic and electronic effects is emphasized in the anomalous behavior of the B2u and B1u bands for low symmetry derivatives.