Topical application of garlic reduces northern fowl mite infestation in laying hens.

Northern fowl mites (NFM) are external parasites that can lower egg production and cause anemia and even death in laying hens. An experiment was conducted with New Hampshire Red and Single Comb White Leghorn laying hens. Hens were individually caged and provided a complete laying diet and water ad libitum. Hens were assigned to groups in a way that assured that treatments, within each breed, would be applied to comparable numbers of birds with light and heavy mite infestations. Each hen was sprayed around the vent with either water or 10% garlic juice in water. Spraying continued each week for 3 wk. During the fourth week, each bird was scored for the presence of NFM on its skin and feathers. A small snippet of feathers was removed from below the vent of each hen and placed in a labeled petri dish with a round, white filter paper insert. The NFM content of each dish was scored by two individuals approximately 1 h after sampling. There was no significant difference in the NFM scores for hens based on breed or future treatment. After the birds were treated for 3 wk, there was no significant difference in external NFM scores based on breed. There were significantly fewer NFM on the birds treated with garlic juice compared with controls, based on external and petri dish scoring (P < 0.002 and P < 0.04, respectively). The reduction in external NFM score was also significant (P < 0.004), with controls declining approximately 0.2 units, whereas garlic-treated hens had a 1.8-unit decrease in external NFM score. Topical application of garlic juice may be an effective way to decrease NFM in laying hens.

The effect of in vitro heat stress on the uptake of neutral red by chicken thrombocytes.

Thrombocytes are multifunctional, nucleated blood cells. Morphological changes in thrombocytes have been used as a physiological indicator of a stress response. This study investigated the effects of in vitro heat stress (HS) on the neutral red uptake activity of chicken thrombocytes. Chicken thrombocytes (98% pure) were prepared from adult Barred Plymouth Rock and Rhode Island Red males. The isolated thrombocytes were preincubated at normal (41 C) or HS (45 C) temperatures for 30 min before either a 30- or 90-min incubation with neutral red at these same temperatures. After incubation the cells were washed, lysed, and the internal neutral red concentrations analyzed. There was no difference in thrombocyte numbers or their uptake of neutral red in samples from males of these two chicken breeds. At 41 C thrombocytes actively took up neutral red over the 90-min incubation period. However, at 45 C thrombocyte internalization of neutral red was significantly reduced. At both time periods (30 and 90 min), thrombocytes at 41 C took up significantly (P < or = 0.05) more neutral red than their counterparts at 45 C. This lack of neutral red uptake was not due to cell death as monitored by Trypan blue exclusion. Following the 30-min incubation there was no difference in viability between thrombocytes at the two temperatures. Although there was a significant (P < or = 0.05) increase in cell death at 90 min for thrombocytes kept at 45 C, the livability difference was of a much smaller magnitude than the difference in neutral red uptake when comparing to cells cultured at 41 C. Neutral red uptake is a rapid, inexpensive and repeatable technique for the study of thrombocyte function.

Expression of epidermal growth factor (EGF) and the EGF receptor in the porcine oviduct.

The production, secretion, and localization of epidermal growth factor (EGF) and the distribution of the EGF receptor (EGF-R) were examined in the isthmus (I) and ampulla (A) of the oviducts from cyclic (C) and early-pregnant (P) gilts. Sexually mature gilts (n = 20) were divided equally into two groups: C and P. P gilts were bred twice (at 0 and 24 h), and all gilts were killed 48 h after onset of estrus. After removal of reproductive tracts, oviducts were isolated, flushed, opened longitudinally, divided by anatomical region, cut into 1-3-mm3 pieces, and placed in Dulbecco's modified Eagle's Essential medium (DMEM: F-12 + ITS [insulin, 5 micrograms/ml; transferrin, 5 micrograms/ml; and selenious acid, 5 ng/ml] + antibiotic). Half the tissue and medium were immediately homogenized and centrifuged, and the supernatant was removed. The remaining tissue was cultured in the medium for 24 h at 37 degrees C and 5% CO2, then prepared similarly for analysis. EGF was measured in the supernatant by a heterologous RIA. Concentration of EGF was expressed as nanogram/milliliter of EGF per milligram of protein in wet tissue. EGF concentrations were present in both regions of the oviducts of C and P gilts. It was greater in I than in A tissues for both C (I = 16.21 ng/ml vs. A = 13.91 ng/ml; p < 0.05) and P gilts (I = 14.27 ng/ml vs. A = 12.53 ng/ml; p < 0.10). Higher concentrations of EGF were found in I tissue of C gilts than in P gilts (C = 16.21 ng/ml vs. P = 14.27 ng/ml; p < 0.05). The media assayed from cultured explants of I and A sections from C and P gilts gave results that were highly correlated with those of immediately prepared tissue sections. Localization of EGF in frozen oviductal tissue sections was demonstrated by immunohistochemistry. The primary site of EGF immunostaining occurred in the epithelial cells (with highest intensity at the apical border) of both C and P gilts. A and I tissue sections from C gilts showed localization of EGF immunostaining mainly in epithelial cells and lamina propria cells, while those from P gilts stained less intensely. The presence of EGF-R was shown by incubating tissue imprints and frozen sections with EGF-erythrosin isothiocyanate, which revealed that EGF-R were distributed mainly on the membranes of epithelial cells. The study indicates that EGF and EGF-R are present in oviductal epithelial cells in both C and P gilts, with the highest concentration of EGF in C gilts.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of ergovaline, loline, and dopamine antagonists on rat pituitary cell prolactin release in vitro.

Cultured rat pituitary cells were studied to: determine the effects of ergovaline and loline on in vitro prolactin release; delineate the agonistic activity of these alkaloids at the D2 dopamine receptor, using 2 selective D2 dopamine receptor antagonists; and compare the efficacy of 2 dopamine receptor antagonists in reversing effects of the treatments on in vitro prolactin secretion. Ergovaline reduced in vitro prolactin release by at least 40% (P < 0.05) at concentrations of 10(-4), 10(-6), and 10(-8) M. However, loline reduced (P < 0.05) prolactin release only at the highest concentration, 10(-4) M. Two standard dopamine agonists, dopamine and alpha-ergocryptine, were used to verify that the inhibitory control mechanisms of in vitro prolactin release were intact. Both compounds reduced prolactin release by at least 40% for concentrations of 10(-4), 10(-6), or 10(-8) M. Selective D2 dopamine receptor antagonists (10(-6) M), domperidone and sulpiride, reversed (P < 0.05) the effect of loline on in vitro prolactin release. However, only domperidone (10(-6) M) was able to reverse (P < 0.05) the effect of ergovaline and only at the lowest ergovaline concentration (10(-8) M). Domperidone was more effective (P < 0.05) in reversing the prolactin-suppressing effect of alpha-ergocryptine than was sulpiride. The dose-response curve for domperidone (cubic fit, P < 0.0001) indicated a threshold concentration (10(-7) M) for reversal of alpha-ergocryptine's (10(-8) M) effect on prolactin release. However, at similar concentration of sulpiride (quadratic fit, P < 0.007), a threshold level was not obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

Ovarian follicular growth and maturation in the domestic pigeon and guinea fowl (Numida meleagris).

Yolks of pigeon and guinea fowl eggs were examined for the number of dichromate-staining rings. Estimates of the time for rapid follicular development using this technique were 5.1 and 5.6 days for pigeons and guinea fowl, respectively. Another measure of follicular development based on the incorporation of Sudan dyes into the yolk yielded an estimate of 6.5 and 8.3 days for pigeons and guinea fowl, respectively. Using one and two-egg clutches, no differences due to clutch position were observed in either species. There was a significant difference (P less than or equal to .01) between results obtained with the two techniques for measuring the period of rapid yolk deposition. The dichromate technique can give valuable data relative to yolk deposition, especially in species where it is impractical to daily catch and administer Sudan dyes. But the tendency to underestimate the period of follicular growth means that caution must be exercised in comparing results obtained with that technique and the more labor-intensive Sudan dye incorporation method. The time from the end of yolk deposition until oviposition is defined as the rest period. This interval was 1.5 days for pigeons and 1.7 days for guinea fowl. This is considerably longer than the rest period of Coturnix quail but similar to that found in turkeys and chickens.

In vivo responsiveness of the broilers' adrenocortical system.

The possible interaction of circadian rhythms in serum concentrations of corticosterone (B) with the response of broiler cockerels to heat stress (HS) and adrenal manipulation with adrenocorticotropic hormone (ACTH) and dexamethasone acetate (DA) was investigated. Adrenocortical response, as indicated by corticosterone concentrations, was greater early in the photoperiod in cockerels exposed to HS or injected with ACTH. A single injection of DA tended to be more inhibitory on B when administered later in the photoperiod.

Daily variation of corticosterone and thyroid hormones in broiler cockerels.

An experiment was conducted to monitor fluctuations in the major adrenal steroid, corticosterone (B), and two iodinated thyroid hormones, triiodothyronine (T3) and thyroxine (T4), over the course of a 24-hr day in broiler cockerels. A circadian variation was observed in B concentrations with the highest found at 0130 hr (23 hr light: 1 hr darkness; photophase beginning at 0100 hr). No circadian variation was observed for either T3 or T4.

Seminal plasma androgen-binding protein activity in turkeys with normal white or abnormal yellow semen.

Dihydrotestosterone (DHT) binding activity of normal white and abnormal yellow turkey semen was quantitated by disc-gel electrophoresis in the presence of [3H]DHT. White seminal plasma had three peaks of activity (Rf = 0.3, 0.5 and 0.8). Yellow seminal plasma had a greater protein concentration and [3H]DHT binding activity averaging 32.5 +/- 7.93 pmol DHT/ml compared with 1.45 +/- 0.3 pmol DHT/ml for white seminal plasma. The majority of [3H]DHT binding was localized at Rf = 0.5 for the yellow seminal plasma. When labelled samples were separated by electrophoresis on unlabelled gels, the only peak of activity was at Rf = 0.5. Blood serum contained 3 peaks of activity (Rf = 0.4, 0.5, and 0.8). We conclude that a seminal plasma androgen-binding protein is present in the domestic turkey, and in males with yellow semen syndrome androgen-binding activity is increased.

Determination of dexamethasone and corticosterone half-lives in male broilers.

Normal broiler males were used in a series of experiments to determine the rate of disappearance of dexamethasone, a synthetic corticoid, and corticosterone, the quantitatively most important glucocorticoid in the bird. Determination of the half-life (T1/2) of these compounds following an intravenous bolus injection was by high performance liquid chromatography. Half-lives for dexamethasone and corticosterone were found to be 36 and 22 min, respectively. The slower rate of disappearance from the blood may help to explain the ability of dexamethasone to overcome some of the problems associated with hyperthermic stress in birds. This method of quantitating exogenously administered steroids is applicable not only to basic research but also to analyses by inspection and regulatory agencies.

Response of broilers and capons to heat stress following adrenal manipulation.

Five-week-old capons and normal broiler males were used in an experiment to test the effect of caponization and adrenal cortical manipulation on subsequent heat stress survival. Saline, adrenocorticotropin (ACTH) at 20 IU/kg, or metyrapone at 60 mg/kg was given daily at either 0730 or 1400 hr. No differences attributable to the time of injection were found. Prestress weights for all groups were not significantly different. Capons and sham-operated males receiving either the vehicle or metyrapone showed significantly higher heat stress mortality (P less than .01) than capons receiving ACTH. This suggests an important adrenal contribution in the ability of young chickens to withstand high environmental temperatures. The results also indicate that the susceptibility of male broilers to heat stress is not directly related to the testes.

Induced gonadotropin release in adrenocorticotropin-treated bulls and steers.

The effect of adrenocorticotropin hormone (ACTH) on plasma cortisol and on gonadotropin releasing hormone (GnRH)-induced release of luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone was determined in nine Holstein bulls and 12 Holstein steers. Treatments consisted of animals receiving either GnRH (200 micrograms, Group G), ACTH (.45 IU/kg BW, Group A) or a combination of ACTH followed 2 h later by GnRH (Group AG). Group G steers and bulls had elevated plasma LH and FSH within .5 h after GnRH injection and plasma testosterone was increased by 1 h after GnRH injection in bulls. In Group A, plasma cortisol was elevated by .5 h after ACTH injection in both steers and bulls, but plasma LH and FSH were unaffected. In Group A bulls, testosterone was reduced after ACTH injection. In Group AG, ACTH caused an immediate increase in plasma cortisol in both steers and bulls, but did not affect the increase in either plasma LH or FSH in response to GnRH in steers. In Group AG bulls, ACTH did not prevent an increase in either plasma LH, FSH or testosterone in response to GnRH compared with basal concentrations. However, magnitude of systemic FSH response was reduced compared with response in Group G bulls, but plasma LH and testosterone were not reduced. The results indicate that ACTH caused an increase in plasma cortisol, but did not adversely affect LH or FSH response to GnRH in steers and bulls. Further, while testosterone was decreased after ACTH alone, neither ACTH nor resulting increased plasma cortisol resulted in decreased testosterone production in the bull after GnRH stimulation.

Response of broilers to hyperthermic stress following treatment with a new cyclo-oxygenase inhibitor.

Two trials were conducted using broiler chickens to test the efficacy of pretreatment with Banamine, an inhibitor of prostaglandin synthesis, on various heat stress indices. Significant differences were found in peripheral prostaglandin F (PGF) levels between immature male and female broilers with pullets having a higher concentration. Females also had less mortality during the hyperthermic challenge, which was independent of medication treatment. Confinement and transport of male broilers resulted in elevated levels of PGF, which were markedly lowered near the time of heat stress death. All levels of Banamine appeared to give some measure of protection against heat stress in male broilers as evidenced by higher survival rates and longer survival times.

Ovarian responses and serum LH levels after retraction or removal of the oviduct in Japanese quail.

The effects of oviduct removal, oviduct displacement or sham-operation were studied in Japanese quail (Coturnix coturnix japonica). No significant differences were observed between the treatments for body weight, number of follicles larger than or equal to 6 mm diam., or number of ruptured follicles. Retraction or removal of the oviduct resulted in similar significant increases (P less than 0.05) in ovarian weight, diameter of the largest follicle, and serum LH levels when compared with the controls. Injection of yolk into normal hens did not cause any change. It is suggested that the oviduct normally exerts an inhibitory control on ovary growth without appreciable effect on ovulation rate.

A new technique in avian semen evaluation.

Modification of a technique used in human fertility is presented and shown to be a simple, inexpensive and quantitative method for estimating the subsequent fertility of a semen sample.

Plasma LH progesterone concentrations in the turkey hen during the ovulatory cycle.

Progesterone and luteinizing hormone (LH) were measuured in the plasma of Large White turkey hens at frequent intervals during the ovulatory cycle and during the periods when ovulations did not occur. The hormones were quantitated at the beginning and the end of the reproductive season to follow the change in patterns and concentrations of these hormones. Radioimmunoassay procedures were used to assay both hormones. Both progesterone and LH reached a peak amount at about 8 to 2 hours before ovulation. At no time did the progesterone peak precede that of LH. On the other hand, the peak of progesterone was observed to last somewhat longer than the LH peak. Progesterone and LH concentrations demonstrated no peak during the non-ovulatory periods. The patterns of both hormones at the end of the reproductive season was about the same as at the beginning of the season, but with lower concentrations.