New blossoms in the neural crest field: trophic and transcription factors.

Just as the answers to some of the most basic, long-standing questions concerning neural crest differentiation have become apparent, the field has been invigorated by a cross-fertilization of mouse genetics, and studies on transcription factors and trophic/instructive factors. These findings raise new questions, at a deeper level of inquiry.

Egg yolk and serum antibody titers of broiler breeder hens immunized with uricase and or urease.

This study evaluated whether broiler breeder hens immunized with uricase (UC), urease (UE), or UC + UE would develop antibody (IgY) titers against these enzymes to prevent manure-N degradation and NH(3) release. Ross × Arbor Acres hens were assigned to PBS (control), UC, UE, or UC + UE injection treatments. Each group had 19 hens per treatment. On d 0, each of the enzymes or PBS was emulsified with complete Freund's adjuvant and administered intramuscularly, whereas on d 7 and 14, a booster injection of PBS or enzymes was administered as an incomplete adjuvant. Blood samples were taken on d 0, 4, 9, 12, 17, 21, and 24 for serum-specific IgY titer analysis. Eggs were collected for yolk-specific IgY titer analysis. Manure samples were taken for nutrient, pH, and NH(3) measurements. Elevated egg yolk anti-UC-IgY titers were observed from UC-immunized hens after the second immunization (P ≤ 0.0001), and they remained higher than those of the PBS- or UE-immunized hens from d 9 to 24. After the first injection, egg yolk anti-UE-IgY titers from hens immunized with UE or the combined antigen were greater than those of birds injected with PBS or UC (P ≤ 0.01). The serum anti-UC-IgY response to UC immunization was observed after the first injection (P ≤ 0.01) and on d 9 (P ≤ 0.0001), and titers remained greater than those of hens immunized with PBS or UE until d 28. The serum anti-UE-IgY titers remained low until much later compared with the anti-UC-IgY titers. Only at 24 and 28 d were anti-UE-IgY titers significantly greater in the UE-immunized hens than in hens immunized with PBS or UC. Hens immunized with UC or UE responded with both egg yolk and serum IgY titers. The combined antigens were significantly greater than the PBS control but had less effect than the individual UC or UE in both the egg yolk and serum. These findings indicate that despite measurable egg yolk and serum IgY titers, immunizing hens with UC, UE, or the combined antigens did not affect the manure nutrients or NH(3) emissions of the treated hens.

The efficacy of pulsed ultraviolet light processing for table and hatching eggs.

In the United States, every year an average of 287.1 eggs are consumed per person, and over 14.1 billion eggs are set in hatchery incubators to produce chicks destined for the egg and meat bird industries. By reducing the microbial load on eggs, food-borne-associated outbreaks can be reduced while good chick health is maintained. Pulsed ultraviolet (PUV) light system delivers an energy-intense broad spectrum (100-1,100 nm) pulse derived from a xenon flashlamp. In recent years, PUV light has been shown to reduce microbial pathogens on the surface of shell eggs by using a static PUV light system. In this study, shell eggs were surface inoculated with Escherichia coli or Enterococcus faecium and treated with PUV light using a modified egg candling conveyor that provided complete rotation of eggs under a flashlamp. Pulsed UV light treatment inactivated both microbial strains, with greater energy resulting in a greater germicidal response (P < 0.05). Treatments of 1.0, 2.4, 3.1, and 4.9 J/cm2 resulted in microbial reductions (Log10 CFU/cm2) of 3.83, 4.26, 4.28, and 4.62 for E. coli and 2.04, 3.12, 3.11, and 3.82 for E. faecium, respectively. This study also evaluated the effects of PUV light treatment of hatching eggs (commercial Leghorn hybrids) on both embryo and chick growth parameters. Using the same system, 4 replicates of 125 fertile eggs per rep were treated with 0 (control), 4.9, 24.4, or 48.8 J/cm2 of PUV light. After processing, eggs were placed in a commercial incubator under normal incubation conditions. There was no significant effect of the PUV light treatment on percent fertility, hatchability, or hatch (P > 0.05). Furthermore, there were no significant effects on posthatch observations, including livability and average bird weight at hatch or at 42 d of age (P > 0.05). In conclusion, this study supports the application of PUV light as an effective antimicrobial intervention for both table and hatching eggs.

The impact of dietary Black Soldier Fly larvae oil and meal on laying hen performance and egg quality.

Recently, the US FDA and Association of American Feed Control Officials approved Black Soldier Fly larvae (BSFL) as a feed ingredient for poultry. The objectives of this work were 1) to evaluate the nutritional profile of BSFL oil and meal in laying hens, and 2) measure the impact of the BSFL treatments on hen performance and egg quality. In 2 experiments, BSFL oil and meal were fed to replicate hens from 43 to 47 wk and from 51 to 55 wk of age. The hens were fed isocaloric, isonitrogenous diets with 3 treatment levels of BSFL oil (1.5, 3, and 4.5%, Exp. 1) or BSFL meal (8, 16 and 24%, Exp. 2). Data were analyzed by one-factor ANOVA for the main effect of diet and Tukey's multiple comparison for mean separation when significant. Exp. 1 results suggest BSFL oil could readily substituted for soybean oil with commercial hens at inclusion levels up to 4.5%. ADFI, BW, egg production, FCR, and egg weight were not impacted by the oil treatments (P > 0.05). Yolk color among hens fed the BSFL oil was greater averaging 7.88 compared to 7.37 from Control hen eggs (P = 0.0001). Exp. 2 diet formulation replaced soybean oil and meal with BSFL meal, and some additional corn was used in the higher BSFL diets. Diet amino acid balance at the highest level of inclusion (24% BSFL meal) indicates arginine and tryptophan are limiting and ADFI, BW and egg production were reduced (P < 0.05). Egg production averaged 85.14% for the Control, 8 and 16% BSFL meal hens and was significantly greater than hens fed 24% meal at 77.01%. However, 8 and 16% BSFL meal levels had no negative impact on performance and were not significantly different than the Controls. Yolk color was again higher among the meal treatments compared to the control (P = 0.0351). These experiments indicate that BSFL oil and meal can be used as dietary energy, protein and amino acids for hen maintenance, egg production and yolk coloration, although there may be upper limits of dietary inclusion.

Primary cultures of dissociated sympathetic neurons. I. Establishment of long-term growth in culture and studies of differentiated properties.

Rat sympathetic ganglia were disrupted by mechanical agitation to yield dissociated primary neurons, and the conditions for long-term growth in culture of the isolated neurons were examined. The neurons were grown with or without non-neural cells, simply by the addition or deletion of bicarbonate during growth in culture. Fluorescence histochemistry indicated that the isolated neurons contained catecholamines; incubations with radioactive precursors were used to verify the synthesis and accumulation of both dopamine and norepinephrine. The neurons also produced octopamine using tyramine as precursor, but not with tyrosine as the precursor. In the presence of eserine, older cultures synthesized and stored small amounts of acetylcholine. The cultures did not synthesize and accumulate detectable levels of radioactive gamma-aminobutyric acid, 5-hydroxytryptamine, or histamine.

Primary cultures of dissociated sympathetic neurons. II. Initial studies on catecholamine metabolism.

Initial studies are reported on the catecholamine metabolism of low-density cultures of dissociated primary sympathetic neurons. Radioactive tyrosine was used to study the synthesis and breakdown of catecholamines in the cultures. The dependence of catecholamine synthesis and accumulation on external tyrosine concentration was examined and a concentration which is near saturation, 30 microM, was chosen for further studies. The free tyrosine pool in the nerve cells equilibrated with extracellular tyrosine within 1 h; the total accumulation of tyrosine (free tyrosine plus protein, catecholamines, and metabolites) was linear for more than 24 h of incubation. Addition of biopterin, the cofactor of tyrosine hydroxylase, only slightly enhanced catecholamine biosynthesis by the cultured neurons. However, addition of reduced ascorbic acid, the cosubstrate for dopamine beta-hydroxylase, markedly stimulated the conversion of dopamine (DA) to norepinephrine (NE). Phenylalanine, like tyrosine, served as a precursor for some of the DA and NE produced by the cultures, but tyrosine always accounted for more than 90% of the catecholamines produced. The DA pool labeled rapidly to a saturation level characteristic of the age of the culture. The NE pool filled more slowly and was much larger than the DA pool. The disappearance of radioactive NE and DA during chase experiments followed a simple exponential curve. Older cultures showed both more rapid production and more rapid turnover of the catecholamines than did younger cultures, suggesting a process of maturation.

Primary cultures of dissociated sympathetic neurons. III. Changes in metabolism with age in culture.

Several biochemical parameters of dissociated sympathetic neurons from superior cervical ganglia of the newborn rat were monitored as a function of age in culture. The neurons, which were grown in the virtual absence of non-neural cells, displayed a striking increase in their ability to synthesize and accumulate catecholamines. This capacity increased 50-fold during a 3-wk period in vitro, after which it appeared to reach a steady level. The major change took place during the second week. The time course of this change was not affected by plating the neurons at a higher cell density. The change in the catecholamine metabolism was far greater in magnitude and quite different in time course from the overall growth of the cells which was monitored by the incorporation of radioactive tyrosine into protein, lipid synthesis from radioactive choline, and incorporation of radioactive uridine into acid-precipitable material. Of the total tyrosine used by the cultures, the proportion devoted to catecholamine synthesis increased to 25% (a 10-fold rise) during the 3-wk period. This changing pattern of metabolism in the cultures suggested a process of maturation which may be similar to neuronal development in vivo.

Role of nerve growth factor in the development of rat sympathetic neurons in vitro. I. Survival, growth, and differentiation of catecholamine production.

To study the effect of nerve growth factor (NGF) on neuronal survival, growth, and differentiation, cultures of dissociated neonatal rat sympathetic neurons virtually free of other cell types were maintained for 3-4 wk. In the absence of NGF, the neurons did not survive for more than a day. Increased levels of NGF increased neuronal survival and growth (total protein and total lipid phosphate); saturation occurred at 0.5 microgram/ml 7S NGF. Neuronal differentiation examined by measuring catecholamine (CA) production from tyrosine also depended on the level of NGF in the culture medium. As the NGF concentration was raised, CA production per neuron, per nanogram protein, or per picomole lipid phosphate increased until saturation was achieved between 1 and 5 microgram/ml 7S NGF. Thus, NGF induces neuronal survival, growth, and differentiation of CA production in a dose-dependent fashion. Neuronal growth and differentiation were quantitatively compared in the presence of the high and low molecular weight forms of NGF; no significant functional differences were found.

Role of nerve growth factor in the development of rat sympathetic neurons in vitro. II. Developmental studies.

Adrenergic sympathetic neurons were grown for 4 wk in submaximal and saturating concentrations of nerve growth factor (NGF) in the virtual absence of non-neuronal cells. In 0.2 or 5 microgram/ml 7S NGF, the neurons gradually decreased in number during the first week, although fewer neurons died at the higher level. No significant change in cell number was observed thereafter. Total neuronal protein, a measure of cell growth, increased linearly with age in both concentrations of NGF. At each age, neurons in high NGF exhibited greater growth per cell than those in low NGF. The ability of neurons to produce catecholamine (CA) increased dramatically during the second and third weeks in both concentrations of NGF, and along a similar time-course, although neurons in submaximal NGF developed a lesser capacity for CA production. As neurons developed in culture, they became less dependent on NGF for survival and CA production, but even in older cultures, approximately 50% of the neurons died when NGF was withdrawn.

Role of nerve growth factor in the development of rat sympathetic neurons in vitro. III. Effect on acetylcholine production.

The effect of nerve growth factor (NGF) on the development of cholinergic sympathetic neurons was studied in cultures grown either on monolayers of dissociated rat heart cells or in medium conditioned by them. In the presence of rat heart cells the absolute requirement of neurons for exogenous NGF was partially spared. The ability of heart cells to support neuronal survival was due at least in part to production of a diffusable NGF-like substance into the medium. Although some neurons survived on the heart cell monolayer without added NGF, increased levels of exogenous NGF increased neuronal survival until saturation was achieved at 0.5 microgram/ml 7S NGF. The ability of neurons to produce acetylcholine (ACh) from choline was also dependent on the level of exogenous NGF. In mixed neuron-heart cell cultures, NGF increased both ACh and catecholamine (CA) production per neuron to the same extent; saturation occurred at 1 microgram/ml 7S NGF. As cholinergic neurons developed in culture, they became less dependent on NGF for survival and ACh production, but even in older cultures approximately 40% of the neurons died when NGF was withdrawn. Thus, NGF is as necessary for survival, growth, and differentiation of sympathetic neurons when the neurons express cholinergic functions as when the neurons express adrenergic functions (4, 5).

A monoclonal antibody that blocks the activity of a neurite regeneration-promoting factor: studies on the binding site and its localization in vivo.

Work from several laboratories has identified a proteoglycan complex secreted by a variety of non-neuronal cells that can promote neurite regeneration when applied to the surface of culture dishes. Using a novel immunization protocol, a monoclonal antibody (INO) was produced that blocks the activity of this outgrowth-promoting factor (Matthew, W. D., and P. H. Patterson, 1983, Cold Spring Harbor Symp. Quant. Biol. 48:625-631). We have used the antibody to analyze the components of the active site and to localize the complex in vivo. INO binding is lost when the complex is dissociated; if its components are selectively reassociated, INO binds only to a complex containing two different molecular weight species. These are likely to be laminin and heparan sulfate proteoglycan, respectively. On frozen sections of adult rat tissues, INO binding is present on the surfaces of glial cells of the peripheral, but not the central, nervous system. INO also binds to the basement membrane surrounding cardiac and skeletal muscle cells, and binding to the latter greatly increases after denervation. In the adrenal gland and kidney, INO selectively reacts with areas rich in basement membranes, staining a subset of structures that are immunoreactive for both laminin and heparan sulfate proteoglycan. In general, the outgrowth-blocking antibody binds to areas known to promote axonal regeneration and is absent from areas known to lack this ability. This suggests that this complex, which is active in culture, may be the physiological substrate supporting nerve regeneration in vivo.

The cholinergic neuronal differentiation factor from heart cells is identical to leukemia inhibitory factor.

A protein secreted by cultured rat heart cells can direct the choice of neurotransmitter phenotype made by cultured rat sympathetic neurons. Structural analysis and biological assays demonstrated that this protein is identical to a protein that regulates the growth and differentiation of embryonic stem cells and myeloid cells, and that stimulates bone remodeling and acute-phase protein synthesis in hepatocytes. This protein has been termed D factor, DIA, DIF, DRF, HSFIII, and LIF. Thus, this cytokine, like IL-6 and TGF beta, regulates growth and differentiation in the embryo and in the adult in many tissues, now including the nervous system.

Dietary camelina meal versus flaxseed with and without supplemental copper for broiler chickens: live performance and processing yield.

An experiment was conducted to compare the responses of young broiler chickens to corn-soybean meal diets supplemented with flaxseed or camelina meal versus a corn-soybean meal control and the factorial effect of 150 mg/kg of Cu supplementation on performance and processing yield. A randomized complete block design with a 2 x 3 factorial arrangement was used with 7 replicates from hatch to 21 d of age (n = 294; 7 chicks per replicate). Body weight of birds fed 10% camelina meal or 10% flaxseed was significantly reduced compared with the control birds. Addition of Cu significantly increased BW and feed consumption of the birds fed the control diet throughout the study. Copper supplementation to the 10% camelina meal diet also increased BW (P < 0.001) with no effect on feed consumption or feed conversion at 21 d. In addition, hot carcass weight, yield, and carcass parts were significantly improved among birds fed the Cu-supplemented control diet. A significant Cu x diet interaction was observed for hot carcass weight and yield, indicating Cu supplementation to the control diet was superior for carcass weight to the other treatments. However, yield was greater for the camelina diets and the control + Cu versus the other treatments. Results from the present study demonstrated that either 10% camelina meal or 10% flaxseed diets will reduce broiler BW when fed the first 3 wk of life. However, birds fed the camelina diet responded to Cu sulfate supplementation with improved live performance and carcass characteristics. Birds fed the 10% flaxseed diets showed no beneficial effect resulting from Cu supplements.

Feeding broiler chicks diets containing keto- and hydroxy-acids: performance and carcass weight.

This study evaluated reduced dietary CP and supplementing amino acid analogs to sustain growth and carcass weight in 0- to 21-day-old Cobb × Avian-48 male broiler chicks. A total of 6 diets with 3 levels of CP (22.5, 19.5, and 16.5%) and 2 sources of AA analogs, either synthetic amino acids (SA) or keto-/hydroxy-acids (KA), were assigned randomly to 36 cages (8 chicks/cage) in a 3 × 2 factorial design. For SA diets, DL-Met, DL-Met + L-Ile, and D-Met + L-Ile + L-Val were used to supplement 22.5, 19.5, and 16.5% CP diets, respectively, and for corresponding KA diets, DL-Met was replaced with methionine hydroxy analog (MHA), L-Ile was replaced with keto-Ile, and L-Val was replaced with keto-Val. Water and all isocaloric diets (3,050 kcal ME/kg) were given ad libitum. Lowering dietary CP to 16.5% reduced BW at 7, 14, and 21 D (P ≤ 0.0001) and feed intake at 8 to 14, 15 to 21, and 0 to 21 D (P ≤ 0.001). Body weight gain (BWG) was reduced and feed-to-gain ratio (FGR) was increased (P ≤ 0.003 to 0.0001) at all times for chicks fed 16.5% CP; however, chicks fed 22.5 and 19.5% CP had comparable performance. Differences in 0 to 7 D BWG (SA, 122.9 vs. KA, 113.9 g/bird; P ≤ 0.04), a 0 to 21 D FGR cumulative effect (1.45 vs. 1.51; P ≤ 0.02), and a 15 to 21 D (P ≤ 0.04) and 0 to 21 D (P ≤ 0.05) CP × AA interaction were also observed. Greater liver weight among 16.5 vs. 19.5 or 22.5% CP fed chicks was found at 14 and 21 D (P ≤ 0.0001 and P = 0.06, respectively). Lower dietary CP reduced spleen weight on day 21 birds (P ≤ 0.0005) with lighter spleens among 16.5 and 19.5% vs. the 22.5% CP fed group (0.090, 0.095, 0.119 g/100 g BW, respectively). Breast weight at 21 D was significantly less for 16.5 vs. 22.5% CP fed chicks. Fat pad weight on day 21 was heaviest among 16.5% chicks (P ≤ 0.0004). Overall, lowering dietary CP to 16.5% had a negative effect, but keto-acid supplementation supported 0 to 21 D broiler growth compared to SA; however, transamination efficiency of KA may be lower for 0 to 7D old chicks compared to older birds.

Separation and partial characterization of neuropeptide-inducing factors in heart cell conditioned medium.

Various conditioned media contain multiple factors that regulate the expression of the neurotransmitters acetylcholine, serotonin, and catecholamines and the neuropeptides substance P, somatostatin, vasoactive intestinal polypeptide-related peptides, cholecystokinin, and enkephalins in cultured sympathetic neurons. Using biochemical and immunological methods, we identify at least three distinct factors in heart cell conditioned medium: one induces acetylcholine, substance P, somatostatin, and vasoactive intestinal polypeptide-related peptides while suppressing catecholamine expression, a second factor induces only vasoactive intestinal polypeptide-related peptides, and a third factor induces only somatostatin expression. These observations demonstrate the existence of a group of biochemically and immunologically distinct factors involved in phenotypic specification with unique, but partially overlapping activities. The analogy with the family of differentiation factors in the hematopoietic system is discussed.

A monoclonal antibody that defines rostrocaudal gradients in the mammalian nervous system.

Spinal cord axons display a rostrocaudal, positional bias in their innervation of sympathetic ganglia and intercostal skeletal muscles. In an effort to examine the molecular basis of this positional specificity, we used the cyclophosphamide immunosuppression method to produce monoclonal antibodies that bind preferentially to rostral ganglia. The staining distribution of one of these antibodies, ROCA1, has been analyzed using a novel histological method. A graded decline in binding is observed along the chain of adult rat sympathetic ganglia, as well as in the nerves innervating intercostal muscles. The antigen is identified on immunoblots as a 65 kd protein, whose distribution corresponds to the pattern found histologically. Surprisingly, ROCA1 appears to bind to glial cells, implying rostrocaudal, molecular differences in their surfaces.

Leukemia inhibitory factor mediates an injury response but not a target-directed developmental transmitter switch in sympathetic neurons.

Leukemia inhibitory factor (LIF; also known as cholinergic differentiation factor) is a multifunctional cytokine that affects neurons, as well as many other cell types. To examine its neuronal functions in vivo, we have used LIF-deficient mice. In culture, LIF alters the transmitter phenotype of sympathetic neurons, inducing cholinergic function, reducing noradrenergic function, and altering neuropeptide expression. In vivo, a noradrenergic to cholinergic switch occurs in the developing sweat gland innervation, and changes in neuropeptide phenotype occur in axotomized adult ganglia. We find that the gland innervation of LIF-deficient mice is indistinguishable from normal. In contrast, neuropeptide induction in ganglia cultured as explants or axotomized in situ is significantly suppressed in LIF-deficient mice. Thus, LIF plays a role in transmitter changes induced by axotomy but not by developmental interactions with sweat glands.

Temperature sequence of eggs from oviposition through distribution: production--part 1.

During Egg Safety Action Plan hearings in Washington, DC, many questions were raised concerning the egg temperature (T) used in the risk assessment model. Therefore, a national study was initiated to determine the T of eggs from oviposition through distribution. In part 1; researchers gathered data on internal and surface egg T from commercial egg production facilities. An infrared thermometer was used to rapidly measure surface T, and internal T was determined by probing individual eggs. The main effects were geographic region (state) and season evaluated in a factorial design. Egg T data were recorded in the production facilities in standardized comparisons. Regression analysis (P < 0.0001) showed that the R(2) (0.952) between infrared egg surface T and internal T was very high, and validated further use of the infrared thermometer. Hen house egg surface and internal T were significantly influenced by state, season, and the state x season interaction. Mean hen house egg surface T was 27.3 and 23.8 degrees C for summer and winter, respectively, with 29.2 and 26.2 degrees C for egg internal T (P < 0.0001). Hen house eggs from California had the lowest surface and internal T in winter among all the states (P < 0.0001), whereas the highest egg surface T were recorded during summer in North Carolina, Georgia, and Texas, and the highest internal T were recorded from Texas and Georgia. Cooling of warm eggs following oviposition was significantly influenced by season, state, and their interaction. Egg internal T when 3/4 cool was higher in summer vs. winter and higher in North Carolina and Pennsylvania compared with Iowa. The time required to 3/4 cool eggs was greater in winter than summer and greater in Iowa than in other states. These findings showed seasonal and state impacts on ambient T in the hen house that ultimately influenced egg surface and internal T. More important, they showed opportunities to influence cooling rate to improve internal and microbial egg quality.

Temperature sequence of eggs from oviposition through distribution: processing--part 2.

The Egg Safety Action Plan released in 1999 raised questions concerning egg temperature used in the risk assessment model. Therefore, a national study was initiated to determine the internal and external temperature sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, shell egg processing, and distribution facilities. The experimental design was a mixed model with 2 random effects for season and geographic region and a fixed effect for operation type (inline or offline). For this report, internal and external egg temperature data were recorded at specific points during shell egg processing in the winter and summer months. In addition, internal egg temperatures were recorded in pre- and postshell egg processing cooler areas. There was a significant season x geographic region interaction (P < 0.05) for both surface and internal temperatures. Egg temperatures were lower in the winter vs. summer, but eggs gained in temperature from the accumulator to the postshell egg processing cooler. During shell egg processing, summer egg surface and internal temperatures were greater (P < 0.05) than during the winter. When examining the effect of shell egg processing time and conditions, it was found that 2.4 and 3.8 degrees C were added to egg surface temperatures, and 3.3 and 6.0 degrees C were added to internal temperatures in the summer and winter, respectively. Internal egg temperatures were higher (P < 0.05) in the preshell egg processing cooler area during the summer vs. winter, and internal egg temperatures were higher (P < 0.05) in the summer when eggs were (3/4) cool (temperature change required to meet USDA-Agricultural Marketing Service storage regulation of 7.2 degrees C) in the postshell egg processing area. However, the cooling rate was not different (P > 0.05) for eggs in the postshell egg processing cooler area in the summer vs. winter. Therefore, these data suggest that season of year and geographic location can affect the temperature of eggs during shell egg processing and should be a component in future assessments of egg safety.

Temperature sequence of eggs from oviposition through distribution: transportation--part 3.

The Egg Safety Action Plan released in 1999 raised many questions concerning egg temperature used in the risk assessment model. Therefore, a national study by researchers in California, Connecticut, Georgia, Iowa, Illinois, North Carolina, Pennsylvania, and Texas was initiated to determine the internal and external temperature sequence of eggs from oviposition through distribution. Researchers gathered data from commercial egg production, processing, and distribution facilities. The experimental design was a mixed model with random effects for season and a fixed effect for duration of the transport period (long or short haul). It was determined that processors used refrigerated transport trucks (REFER) as short-term storage (STS) in both the winter and summer. Therefore, this summary of data obtained from REFER also examines the impact of their use as STS. Egg temperature data were recorded for specific loads of eggs during transport to point of resale or distribution to retailers. To standardize data comparisons between loads, they were segregated between long and short hauls. The summer egg temperatures were higher in the STS and during delivery. Egg temperature was not significantly reduced during the STS phase. Egg temperature decreases were less (P < 0.0001) during short delivery hauls 0.6 degrees C than during long hauls 7.8 degrees C. There was a significant season x delivery interaction (P < 0.05) for the change in the temperature differences between the egg and ambient temperature indicated as the cooling potential. This indicated that the ambient temperature during long winter deliveries had the potential to increase egg temperature. The REFER used as STS did not appreciably reduce internal egg temperature. These data suggest that the season of year affects the temperature of eggs during transport. Eggs are appreciably cooled on the truck, during the delivery phase, which was contrary to the original supposition that egg temperatures would remain static during refrigerated transport. These data indicate that refrigerated transport should be a component in future assessments of egg safety.