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Biomedical subjects

S L Pardue

Publications and source records attributed to S L Pardue.

17 recordsLinked to original sources

A harness and computer system to facilitate automated body temperature data collection in heat-stressed broilers.

An easy-to-use, low-cost system was developed that permitted nearly continuous, automated core body temperature (Tc) readings on 7-wk-old male broiler chickens via direct computer linkage to thermistor probes held in place by a specially designed harness. Elevated Tc was noted in heat stress studies following the replacement of expelled temperature probes in some hyperthermic birds. To demonstrate the usefulness of the data collection system described herein, three treatments with three to four birds per treatment were used to examine this observation. Birds were designated as handled only (HAN), handled to remove and replace the temperature probe (RPL), or left as nonhandled controls (CON). Treatments had no effect on subsequent Tc in experiments when the thermoregulatory capacity of the birds was not challenged. However, when the birds were sufficiently challenged, Tc of HAN and RPL birds increased within 4 min of the initiation of handling and remained above baseline for up to 45 min. The Tc of CON birds in that trial also increased, but to a smaller degree, within 5 min and remained above baseline for up to 20 min. This study indicates that Tc of hyperthermic birds can be superelevated by simulated manual placement of cloacal temperature probes and that fixed probes connected to an automated data monitoring and collection system is a relatively simple way to avoid this problem.

Animals

Effect of ascorbate on luteinizing hormone stimulated progesterone biosynthesis in chicken granulosa cells in vitro.

1. Utilizing hen granulosa cells from the two largest (F1 and F2) follicles, we have examined the effect of sodium ascorbate (AS) on luteinizing hormone (LH) stimulated progesterone (PR) biosynthesis. 2. In experiment 1, in vitro AS levels as 0.0, 0.2, 0.4 or 0.8 mM were permutated by LH concentrations of 0.0, 1, 10 or 100 ng/ml. 3. Combination of 0.4 or 0.8 mM AS with physiological LH concentrations significantly (P < 0.05) enhanced (up to 28%) PR production. 4. In experiment 2, levels of AS at 0.3 and 0.6 mM significantly increased (up to 29%) LH induced PR synthesis. 5. These findings suggest that AS may be associated with chicken steroidogenesis as has been indicated for mammalian species.

Animals

Influence of a novel oxy-halogen compound on early growth and nitrogen retention of broiler chickens challenged with Salmonella.

The potential of a novel oxy-halogen compound (OHC) to alter early growth and nitrogen retention of broiler chickens challenged with Salmonella was evaluated. Three hundred and twenty female broiler chicks (Arbor Acres x Arbor Acres) were weighed and distributed randomly within a 2 x 4 factorial arrangement of treatments. Main effects examined were the presence or absence of Salmonella typhimurium (ST) inoculation and OHC treatment. At hatching, 80 chicks were placed in electrically heated brooder batteries in each of four identical isolation rooms. Chicks designated to receive 100 microL of an oral inoculum containing 10(5) ST cfu at 3 days of age were in two of the rooms, and uninoculated chicks were raised in the other two rooms. Four replicates of 10 chicks each received drinking water containing either 0, .05, .1, or .5% OHC for each level of ST. Chicks administered .05% OHC exhibited enhanced (P < or = .01) growth at 7 and 14 days of age when compared with control values. A significant OHC by ST interaction was observed at 7 (P < or = .0001) and 14 (P < or = .03) days of age. Feed utilization was improved (P < or = .01) by OHC administration (.05 and .1%) from hatching to 7 days of age. The administration of OHC reduced (P < or = .01) nitrogen excretion and enhanced (P < or = .01) nitrogen retention by chicks at Day 7. Cecal ST log10 counts at 7 days of age for chicks given water containing 0, .05, or .1% OHC were 4.72, 3.93, and 3.74, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Nutritional Physiological Phenomena

Relative bioavailability of L-ascorbyl-2-polyphosphate in broiler chickens.

Broiler chick diets and drinking water were supplemented with two sources of vitamin C: crystalline L-ascorbic acid (AsA) or L-ascorbyl-2-polyphosphate (APP) to provide 0, 25, 50, 100, 200, 400, 800, 1,600, and 3,200 ppm (mg/kg) AsA. The bioavailability of APP relative to AsA, as estimated by the change in plasma AsA concentration, was evaluated during 24-h periods of supplementation. When provided in the feed, no differences in dietary AsA content were attributed to vitamin source. In contrast, APP administration at 25 and 50 ppm, resulted in higher (P < .001) AsA values in drinking water when compared with AsA supplementation. Plasma AsA values were elevated (P < .05) above baseline when either AsA or APP were supplemented in the feed or water at a level of 400 ppm or greater. Plasma AsA concentrations, following supplementation of the diets, were higher (P < .05) in AsA-treated (800 ppm) chicks when compared with APP-supplemented chicks. During water supplementation, AsA (800 ppm) and APP (3,200 ppm) administration resulted in higher plasma AsA values when compared with their alternate vitamin source. At all other levels of water supplementation, no differences in plasma AsA were associated with vitamin source. The absence of a consistent difference in plasma AsA, relative to vitamin source, suggests that the isolated differences observed may be due to chance. It was concluded that APP was of similar bioavailability to that of AsA, as estimated by the ability to elevate plasma AsA concentrations in broiler chicks.

Animals

In ovo administration of boron alters bone mineralization of the chicken embryo.

It has been hypothesized that boron (B) is an essential element for animals, especially in bone metabolism. In this study, the influence of in ovo boron administration was assessed in the chicken. At 8 d of embryogenesis, carrier or B (0.1, 0.5, or 1.0 mg) was injected on to the chorioallantoic membrane of fertile eggs. At hatching, body weights were recorded and tissue samples collected. Although boron failed to alter bone mineralization, it decreased (p less than 0.05) dried bone weight, suggesting a reduction in the bone organic matrix. Furthermore, 1 mg boron decreased (p less than 0.05) hatchability and increased (p less than 0.05) the height of the proliferative zone in the growth plate, indicating an unfavorable effect on bone elongation of the developing chick.

Animals

Autosomal albinism affects immunocompetence in the chicken.

Immune responsiveness of three neonatal and juvenile phenotypes, determined by the albinotic C locus, was evaluated. The phenotypes included normally pigmented (C+/-), recessive white (c/ca), and completely amelanotic albinos (ca/ca). No differences in: (1) primary agglutinin levels directed against sheep red blood cells (SRBC) or Brucella abortus (BA), or (2) cell-mediated immunity, as estimated by in vivo mitogen stimulation, were associated with the albino phenotype. The significant suppression of secondary SRBC or BA agglutinins observed in albino chicks was limited and of questionable biological significance. Acquisition of passively transferred maternal BA agglutinins was significantly impaired in albino progeny irrespective of dam genotype. No differences in agglutinin levels were associated with dam genotype. In addition, uptake of yolk sac contents was retarded significantly in albino chicks at hatch. These data suggest that an impaired ability to absorb maternal antibody and not the capacity to mount an active immune response contributes to neonatal mortality in albino chicks.

Agglutinins

In ovo growth hormone alters growth and adipose tissue development of chickens.

The effect of in ovo administration of ovine growth hormone (oGH) on growth and adipose tissue development of chickens was investigated. Unlike mammalian species, exogenous growth hormone has not been previously shown to increase growth of aves. In trial 1, fertilized eggs were injected with vehicle (.03 M NaHCO3 in .15 M NaCl, pH 8.3), 0.25, 2.5, 25 or 250 micrograms oGH on day 11 of embryogenesis. In trial 2, fertile eggs were injected with vehicle or 250 micrograms oGH. In contrast to previous studies in which GH was administered to growing birds, oGH injected in ovo in the present study increased body weights, skeletal growth and feed efficiencies of male broilers. Growth rate was not altered in females. Adipose cellularity data from both trials indicated that in ovo oGH also altered adipose tissue development of broilers. Seven-week-old male and female broilers treated with oGH during embryogenesis exhibited larger adipocytes with correspondingly less cell per gram of tissue. Additionally, adipocytes from oGH-treated broilers exhibited decreased sensitivity to glucagon, cholera toxin or theophylline-induced lipolysis responsiveness to dcAMP in ovo. Cholera toxin plus theophylline improved the lipolytic response of oGH-treated birds; thus, in broilers injected with oGH cAMP-mediated lipase activation may be reduced by a mechanism of increased phosphodiesterase activity. The results of this study indicate that growth and tissue development of chickens have been altered by mammalian GH in ovo.

Adipose Tissue

Enhanced integumental and ocular amelanosis following the termination of cyclosporine administration.

The Smyth delayed amelanotic line of chickens display symptoms commonly associated with human vitiligo. Administration of the immunosuppressive compound, cyclosporine, significantly delayed the mean age of onset and incidence of integumental pigment losses in this mutant line of vitiliginous chickens. Associated ocular pathology was also less severe in treated chicks. Termination of cyclosporine administration resulted in enhanced integumental and choroidal amelanosis, choroidal inflammation, and chorioretinal damage beyond that observed in nontreated controls. These results suggest that withdrawal of cyclosporine in treatment of this spontaneous autoimmune disease may exacerbate associated symptoms.

Animals

Effect of corticosterone on the incidence of amelanosis in Smyth delayed amelanotic line chickens.

The Smyth Delayed Amelanotic (SDA) line chicken exhibits a postnatal loss of pigment in feathers and choroid presumably due to an autoimmune reaction triggered by a basic pigment cell defect. The present study was designed to determine if the incidence and severity of amelanosis would be affected by administration of corticosterone (CS) in feed. The SDA line chickens were given 0, 20, 30, 40, and 50 ppm CS from 4 to 12 weeks of age. Body weight and incidence of amelanosis were determined weekly and immune response to sheep red blood cells was determined at the end of the trials. Body weight and immune response levels were significantly lower in treated groups than in controls (P less than .001), but no significant differences were found between treated groups on measures of amelanosis or immune response. Incidence of amelanosis in controls (60%) was significantly greater than in treated groups: 20 ppm, 14.2%; 30 ppm, 17.9%; 40 ppm, 12.9%; and 50 ppm, 16.7%. Six weeks posttreatment, treated groups were no longer significantly different from controls in terms of the incidence of amelanosis. It is proposed that the reduction in amelanosis during CS treatment is attributable to suppression of antibody response to the pigment cell antigen by the CS.

Animals

Influence of C locus alleles on neonatal development in the domestic fowl.

Neonatal development, as influenced by the autosomal albino (ca/ca), recessive white (c/ca), or colored (C+/-) genotype, was investigated. Albino chicks exhibited smaller (P less than or equal to .005) body weights at 3, 6, and 9 days of age. A significant (P less than or equal to .005) reduction in growth rate also occurred in albinos from hatching to 3 days of age. Associated with the suppression of growth was the retention of greater (P less than or equal to .05) amounts of yolk sac contents. Albino chicks exhibited smaller (P less than or equal to .01) bursal weights at hatching and 6 days of age. Plasma glucose and protein levels were depressed (P less than or equal to .005) in albinos at hatching when compared to recessive white or colored chicks. No significant differences in plasma glucose or protein were noted at any other time periods. These data provide evidence for the retardation of neonatal development and a reduction in maternal yolk utilization by the ca/ca embryo. We suggest that there may exist additional physiological functions for melanin/functional tyrosinase that are not directly involved with pigmentation.

Alleles

Role of ascorbic acid in chicks exposed to high environmental temperature.

This study was conducted to determine if ascorbic acid (AA) 1) increases resistance to high environmental temperature in young chickens and 2) alters heat-induced changes in several physiological responses. Groups of male chicks received either a standard ration containing 1,000 mg/kg (ppm) of AA or the ration without AA. Chicks were brooded for 3 wk and then maintained at 22 +/- 0.8 degrees C. At 4 wk of age, both AA-supplemented and control chicks were exposed to 30 min of heating (43 +/- 0.1 degrees C and 40 +/- 2% rh) on each of 3 consecutive h in an environmentally controlled chamber. Chicks were challenged with sheep erythrocytes (1 ml, 10(5) cells, iv) 12 h postheating. Heating reduced plasma potassium, body weight gain, relative bursa and spleen weights, and anti-sheep erythrocyte levels. Heating increased cloacal temperature, plasma protein, corticosteroid levels, and mortality. AA ameliorated many of these stress-related responses.

Animals

Influence of supplemental ascorbic acid on broiler performance following exposure to high environmental temperature.

The present study was conducted to determine if dietary ascorbic acid (AA) would improve growth, feed efficiency, and livability of broilers following an acute heating episode. Supplemental AA was provided in the diets at calculated levels of 0, 250, 500, and 1000 ppm, continuously. Females that received 1000 ppm exhibited significantly greater body weights at 2 and 4 weeks of age. No significant effects due to AA supplementation were observed in body weights of males. At 4 weeks of age, chicks were heated on two consecutive days by increasing the ambient temperature (38.3 C at bird level) in the production facility. Heating significantly reduced body weights in males, but not females, at 5 and 7 weeks of age. Feed conversions were increased after heating, but significant effects due to AA were not found. Ascorbic acid did not improve overall livability significantly in either sex, but heat-associated mortality was reduced in supplemented females.

Age Factors

Pleiotropisms associated with alleles of the C locus in the domestic fowl.

Pleiotropisms associated with the recessive white (c) and albino (ca) alleles at the C locus of the domestic fowl were investigated. Hatchability of fertile eggs was not significantly different for the colored (C+/c, C+/ca), recessive white (c/ca), and albino (ca/ca) chicks; however, late embryonic mortality was higher in ca/ca embryos P less than or equal to .005). Albinos exhibited shorter down lengths (P less than or equal to .01), higher incidences of subcutaneous hemorrhage and inflammation (P less than or equal to .01) and an increased incidence of yolk sac protrusions (P less than or equal to .01). Suppressed body weights (P less than or equal to .01) were evident at all times, except at hatching, in both male and female albinos reared in batteries. Recessive white females also exhibited smaller body weights than colored chicks at 7 and 8 weeks of age in battery trials (P less than or equal to .01). Significant suppression of body weights occurred in albinos only at 4 weeks of age in trials where floor rearing was used. Mortality in albinos was also significantly higher, particularly under floor rearing conditions (P less than or equal to .01). In addition, both feed consumption and feed utilization were reduced in albinos (P less than or equal to .01). These data suggest that melanin synthesis is an important component in the expression of a number of important physiological traits and that the C locus exerts a previously undefined regulatory influence on such traits.

Albinism

Evidence for amelioration of steroid-mediated immunosuppression by ascorbic acid.

Four experiments were conducted to determine if supplemental ascorbic acid (AA) would ameliorate the immunosuppression induced by exogenous cortisol (COL). Supplemental AA was provided in the diets at levels of 0 and 1000 ppm. Administration of COL significantly lowered plasma AA at both 0 and 10 days postimmunization, and AA supplementation elevated plasma AA at both times. Cortisol-treated chicks exhibited significantly reduced agglutinins to sheep red blood cells but not to Brucella abortus. Supplemental AA significantly ameliorated the immunosuppression associated with exogenous COL and may serve as an antiimmunosuppressive agent in the chicken.

Agglutinins

Plasma ascorbic acid concentration following ascorbic acid loading in chicks.

Three trials were conducted to determine the changes in plasma ascorbic acid (AA) associated with varying levels and duration of supplemental AA. In Trial 1, supplemental AA was provided in the drinking water at 0, 5, 25, 50, 100, 250, 500, 1000, and 2000 micrograms/ml (ppm). Plasma AA concentrations were significantly elevated in chicks receiving 250 ppm AA or greater. In Trial 2, plasma AA concentrations increased significantly within 4 hr of supplementation in chicks receiving 1000 ppm AA. Statistically, maximum AA values occurred some 8 hr following the initiation of supplementation. Removal of the supplemented water resulted in rapid declines in plasma AA in Trial 3. Plasma AA values significantly higher than controls were maintained 16 hr after the removal of the supplemental water. Values returned to those of controls within 20 hr.

Animals

Humoral immunity in Japanese quail following surgical bursectomy at various ages.

Four separate experiments were conducted to determine the effects of surgical bursectomy (BSX) at periodic intervals on subsequent antibody production in Japanese quail. At 0, 1, 3, 7, and 28 days of age, BSX resulted in graduated increments in humoral immune responsiveness. Quail BSX at 0 and 1 day of age exhibited significantly reduced primary hemagglutinin responses, as well as reduced mercaptoethanol resistant (IgG) antibody levels. The production of mercaptoethanol sensitive antibody (IgM) levels were affected to a lesser degree in BSX quail than in controls. At 7 and 28 days of age, BSX resulted in no significant effects. At 3 days of age, BSX resulted in an intermediate effect with minimal reduction in antibody levels. Secondary antibody responses were reduced to a lesser extent than the primary responses. At 0 day, BSX reduced hemagglutinin and mercaptoethanol sensitive antibody levels during the early stages of the secondary responses. At other times, however, BSX did not affect secondary antibody responses.

Age Factors

The excretory system of young chickens experiencing mercury toxicity--effects on kidney development, morphology, and function.

Four trials were conducted to determine if toxic levels of mercury affect kidney development, morphology, and renal function. Mercury, administered via the drinking water as mercuric chloride caused a reduction in gross kidney weight, an increase in relative kidney weight and a slight but significant increase in the percentage water retained by left kidney of 6-week-old cockerels. Mercury had no effect on renal function of 6-week-old birds as indicated by the clearance of phenol red from circulation. Histological discontinuity of the kidney was extensive and evidenced by foamy cell degeneration and nuclear pyknosis. Although mercury caused gross alterations in the morphology of the kidney, normal excretory function was maintained.

Animals