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PubMed1986

Rupture pressure of elastic and muscular aortic segments from hypertensive and hypotensive turkeys.

Blood pressures and heart rates were recorded from two groups of turkeys in two trials. In trial one 20 turkeys, 36 weeks of age and in trial two 24 turkeys, 14 weeks of age, were used. Immediately after blood pressures and heart rates had been determined, the turkeys were killed and vascular tissues were excised. Equal numbers from hypertensive and hypotensive lines of turkeys were used in each trial to determine the rupture pressure of both the elastic and muscular segments of the aorta. When values for the two trials were combined, mean hydrostatic pressures of 1478, 1804, and 794 mm Hg respectively were required to rupture the most caudal abdominal aortic segment, the adjacent cranial abdominal segment, and the thoracic aortic segment. There was a significant difference between the two lines for blood pressure in both trials and for heart rate in trial 2. There were no statistically significant correlations between blood pressure, atherosclerotic plaque score and rupture pressure. Birds fed on a diet containing added fat and cholesterol had significantly lower blood pressures than the birds fed on the other two diets. Birds receiving added dietary cholesterol and fat had lower heart rates than birds fed on the diet with added fat only. Lower plaques scores were evident in the caudal abdominal aorta of the birds fed on the control diet compared to birds fed on the other two diets.

Animals↗
PubMed1994

Effect of lighting treatment on the productivity, health, behavior and sexual maturity of heavy male turkeys.

1. Turkey poults (1620) were used to compare the effects of three lighting programmes on heavy strain males reared to 188 d: constant light (24L:0D, CON); increasing light (6L:18D at 7 d gradually increasing to 20L:4D by 63 d, INC); a pattern identical to INC followed by a decrease in daylength from 84 d to 10L:14D at 112 d (DID). 2. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio. 3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism. 4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light. 5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation. 6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm2 (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065). 7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P = 0.072). Testosterone concentration was not related to growth rate.

Animal Husbandry↗
PubMed1998

Assessment of alpha-tocopheryl acetate supplementation, addition of salt and packaging on the oxidative stability of raw turkey meat.

1. One-day-old turkey poults (n = 14) were randomised into 2 groups (n = 7) and fed diets containing 20 (E20) and 600 (E600) mg all-rac-alpha-tocopheryl acetate/kg food for 21 weeks prior to slaughter. Two batches were formed from E20 meat (E20) and E20 plus 10 g salt/kg (E20S). Two similar batches were formed from E600 meat (E600) and E600 plus 10 g salt/kg (E600S). 2. The effects of alpha-tocopheryl acetate supplementation and salt addition on the oxidative stability of raw turkey patties was investigated during aerobic and vacuum-packaged refrigerated (4 degrees C) storage. 3. Dietary alpha-tocopheryl acetate supplementation reduced TBARS (thiobarbituric acid reacting substances) numbers for raw overwrapped and vacuum-packaged turkey leg and breast patties. 4. Dietary alpha-tocopheryl acetate had the greatest influence on TBARS numbers for raw overwrapped turkey leg patties. 5. The addition of 10 g salt/kg increased TBARS numbers for overwrapped and vacuum-packaged turkey leg and breast patties. 6. Vacuum-packaged patties remained more oxidatively stable than similarly treated overwrapped patties throughout the experimental period.

Analysis of Variance↗
PubMedDate not supplied

Cadmium and lead in muscle tissue and organs of broilers, turkeys and spent hens and in mechanically deboned poultry meat.

Cadmium and lead levels have been determined in meat, livers and kidneys of turkeys, in livers and kidneys of spent hens, in kidneys of broilers and in mechanically deboned poultry meat (MDPM), by dry ashing of the sample with Mg(NO3)2 followed by differential pulse anodic stripping voltammetric analysis. The possible age-dependent cadmium and lead accumulation in livers and kidneys of turkeys was also studied. The cadmium concentrations in meat and organs of poultry are in good agreement with data reported for other countries, but lead concentrations were low compared with most data reported in the literature. The cadmium levels in kidneys and livers of turkeys increased with age, whilst the lead concentrations were unrelated to age. The cadmium and lead concentrations in industrially prepared MDPM from broiler carcasses were very low (less than 0.001-0.004 mg/kg and less than 0.01-0.06 mg/kg, respectively). In MDPM prepared from backs (including the kidneys) and necks, elevated cadmium concentrations were found. The increase was related to the cadmium concentrations in the kidneys. In MDPM prepared from broilers, turkeys and spent hens the cadmium concentrations varied between 0.001 and 0.002 mg/kg, 0.005 and 0.006 mg/kg and 0.007 and 0.028 mg/kg, respectively. For lead the concentrations in meat and MDPM were similar. It can be concluded from the results that in MDPM prepared from spent hens and possibly turkeys, when incorporating the kidneys, cadmium concentrations greater than 0.05 mg/kg, (the legal limit for cadmium in poultry meat in The Netherlands) may occur.

Aging↗
PubMed2006

Daily oscillation in melatonin synthesis in the Turkey pineal gland and retina: diurnal and circadian rhythms.

The aim of the present study was to examine arylalkylamine N-acetyltransferase (AANAT) activity and melatonin content in the pineal gland and retina as well as the melatonin concentration in plasma of the turkey (Meleagris gallopavo), an avian species in which several physiological processes, including reproduction, are controlled by day length. In order to investigate whether the analyzed parameters display diurnal or circadian rhythmicity, we measured these variables in tissues isolated at regular time intervals from birds kept either under a regular light-dark (LD) cycle or under constant darkness (DD). The pineal gland and retina of the turkey rhythmically produced melatonin. In birds kept under a daily LD cycle, melatonin levels in the pineal gland and retina were high during the dark phase and low during the light phase. Rhythmic oscillations in melatonin, with high night-time concentrations, were also found in the plasma. The pineal and retinal melatonin rhythms mirrored oscillations in the activity of AANAT, the penultimate enzyme in the melatonin biosynthetic pathway. Rhythmic oscillations in AANAT activity in the turkey pineal gland and retina were circadian in nature, as they persisted under conditions of constant darkness (DD). Transferring birds from LD into DD, however, resulted in a potent decline in the amplitude of the AANAT rhythm from the first day of DD. On the sixth day of DD, pineal AANAT activity was still markedly higher during the subjective dark than during the subjective light phase; whereas, AANAT activity in the retina did not exhibit significant oscillations. The results indicate that melatonin rhythmicity in the turkey pineal gland and retina is regulated both by light and the endogenous circadian clock. The findings suggest that environmental light may be of primary importance in the maintenance of the high-amplitude melatonin rhythms in the turkey.

Animals↗
PubMed1980

[Requirements of turkeys kept on the ground with respect to energy and crude protein content of mixed feeds].

In four experiments with 9,500 turkeys assorted according to sex, three energy levels (500, 550 and 600 EFh (energetic feed units for hens = 14,6 kJ net energy body fat of hens)/kg feed) were combined with three levels of crude protein (250, 300 and 350 g/kg feed) in the mixed feed (9 rations) and tested under conditions of keeping the turkeys on the ground from hatching to their 42nd day of life. The feed consumption of the turkeys did not correlate with the energy content of the mixed feed. The energy consumption of the groups whose mixed feed had a high energy content (550 and 600 EFh) was significantly higher than that of groups whose feed had a low energy content. With the increasing content of crude protein in the mixed feed the consumption of crude protein per turkey and test period rose significantly. Due to the increase of the content of energy and crude protein, the live weight gain increased after a 28- and 42-day test period; the growth-stimulating effect was more distinct with male animals. Mortality had no connections with nutrition. For the starting-off feed for turkeys an energy content of < 580 EFh with 300 g crude protein per kg mixed feed up to the 4th/5th week of life is recommended.

Animal Feed↗
PubMed1980

Pasteurella multocida: plasma lysozyme in bacteremic and lipopolysaccharide-exposed turkeys.

Plasma lysozyme was measured in turkeys with experimental fowl cholera produced by either of two serotypes of Pasteurella multocida. Lysozyme was not detected in preexposure plasma, whereas plasma sampled when turkeys were terminally bacteremic contained 7.0-7.5 microgram of lysozyme/ml. Plasma lysozyme was measured in turkeys inoculated intravenously with P. multocida lipopolysaccharide (LPS). Turkeys inoculated with 10 microgram of LPS produced plasma lysozyme detectable for 2 hr after inoculation; those inoculated with 500 microgram of LPS produced plasma lysozyme detectable for at least 6 hr after inoculation. Egg-white lysozyme, equivalent in concentration to the plasma lysozyme detected in bacteremic turkeys, was active upon young cultures of P. multocida and increased the degree of lysis of P. multocida cells treated with deoxycholate. Lysozyme, ethylenediaminetetraacetate, and deoxycholate in combination produced the highest degree of lysis of P. multocida cells.

Animals↗
PubMed1984

Cellulose digestion by domestic turkeys fed low or high fiber diets.

To determine whether dietary preconditioning might improve fibrolysis in turkeys, Wrolstad Medium white hens were fed either a high (16.13%, HF) or low (2.80%, LF) fiber diet for 6-60 weeks. The substrate to test for cellulolysis, [14C]cellulose, was introduced into the gizzard per os or into one cecum via a cannulated fistula. Immediately after [14C]cellulose introduction, turkeys were placed in an airtight chamber (0.3 m3) from which exhaled CO2 was collected and analyzed for 14CO2. An average of 10.4% of the 14C was recovered in CO2 from turkeys fed the HF diet, and only 2.9% was recovered from the LF-fed birds that were orally dosed. In turkeys dosed via cecal cannula, recoveries averaged 15.4 and 2.9% for HF- and LF- fed birds, respectively. Recoveries were 7.0 and 1.4% in HF- and LF-fed turkeys that were cecectomized. Preconditioning to an HF diet does appear to improve cellulolysis.

Animals↗
PubMed2002

Nephrology, dialysis and transplantation in Turkey.

The establishment of the Turkish Society of Nephrology (TSN) in 1970 coincided with that of many western European nephrology societies. The TSN organized the 15th ERA-EDTA Congress in Istanbul in 1978, earlier than many European Countries, and currently has 286 active members. At present, Turkey has 161 nephrologists, which equals 2.5 nephrologists per million population (p.m.p.). The number of original articles submitted by Turkish authors to the journal Nephrology Dialysis Transplantation ranks 7th-8th amongst total submissions to the journal. Turkey also ranks 2nd-4th in the number of abstracts submitted to recent ERA-EDTA Congresses. With 18 063 patients undergoing intermittent haemodialysis treatment in 348 dialysis centres, Turkey has the 5th largest chronic haemodialysis patient population among European countries. In addition, 1903 patients are currently undergoing continuous ambulatory peritoneal dialysis. However, with a total of 4693 renal transplants since 1975, of which only 21.3% were of cadaveric origin, Turkey lags considerably behind other European countries in renal transplantation. In Turkey, the prevalence and incidence of renal replacement therapy (RRT) are at present 358 and 52 p.m.p. respectively, and the expansion rate of the RRT stock is 17% (HD 18.5%, CAPD 6%, and transplantation 1.7%). The yearly gross mortality rate of the total RRT population is 9.4%. The present priorities of the Turkish nephrological community include high-standard research activity and long-term, prospective clinical and epidemiological studies, an increase in the total number and percentage of cadaveric transplants, further improvement of the quality and cost-effectiveness of RRT, and finally the further development of scientific and educational collaboration with the world nephrological community.

Health Care Costs↗
PubMed1989

An outbreak of psittacosis in Minnesota turkey industry workers: implications for modes of transmission and control.

From June through November 1986, an outbreak of psittacosis occurred in turkey industry workers in central Minnesota. A total of 186 suspect cases were identified, and 122 cases (66%) were serologically confirmed. Cases occurred in three turkey processing plants, two rendering plants, one farm, and one "further processing" plant (where meat is removed from previously eviscerated carcasses and consumer products, such as roasts, are made). As in previous outbreaks, workers exposed to the viscera of infected birds were at greatest risk of becoming infected. However, our data showed that 31 (25%) of the confirmed cases occurred in workers at the further processing plant who had contact only with previously eviscerated carcasses. Although the specific source of infection and the mode of transmission in these workers are unclear, the use of gloves and masks by all processing workers during an outbreak might help to limit exposure. Control measures, which focused on identifying and treating ill turkey flocks, were initiated in early September; however, cases continued to occur in turkey industry workers through November. One of the flocks suspected of causing illness appeared healthy and, therefore, was not treated. Chlamydia psittaci infection in this flock was confirmed by culture after the flock had been processed. A rapid test for diagnosing C. psittaci infection in turkey flocks at the time of processing might be useful in preventing exposure of large numbers of workers.

Animals↗
PubMed1992

Interspecies transmission and reassortment of influenza A viruses in pigs and turkeys in the United States.

Genetic reassortment between influenza A viruses in humans and in animals and birds has been implicated in the appearance of new pandemics of human influenza. To determine whether such reassortment has occurred in the United States, the authors compared the genetic origins of gene segments of 73 swine influenza virus isolates (1976-1990), representing 11 states, and 11 turkey virus isolates (1980-1989), representing eight states. The host origin of gene segments encoding the internal proteins of H1N1 swine and turkey influenza viruses was identified by developing a dot-blot assay. All gene segments of swine influenza viruses were characteristic of influenza virus genes from that species, indicating that pigs may not be frequent participants in interspecies genetic exchange and reassortment of influenza viruses in the United States. In contrast, 73% of the turkey influenza virus isolates contained genes of swine origin. One turkey isolate was a reassortant having three genes characteristic of avian influenza virus and three of swine origin. These findings document a high degree of genetic exchange and reassortment of influenza A viruses in domestic turkeys in the United States. The molecular biologic techniques used by the authors should aid future epidemiologic studies of influenza pandemics.

Animals↗
PubMed1998

Dietary threonine responses in growing turkey toms.

A study was conducted to evaluate Thr responses in Large White (British United Turkeys) male turkeys during three time periods: 0 to 3, 3 to 6, and 6 to 9 wk of age. The Thr-deficient diets, fed in 3-wk intervals, were composed primarily of corn, peanut meal, poultry meal, and soybean meal as intact protein sources and supplemented with amino acids. Graded levels of L-Thr were added to the Thr-deficient diets. Another group of turkeys received a corn-soybean-poultry meal control diet in each time period. Diets were formulated to meet a minimum of 110% of suggested amino acid specifications (NRC, 1994) for all essential amino acids, except Thr. Feed intake, BW gain, and feed:gain responses were measured. Average environmental temperatures for Weeks 1, 2, and 3 were 29, 27, and 24 C, respectively. From 4 to 9 wk of age, average environmental temperatures varied between 24 and 35 C. Turkeys in each time period responded to Thr in a curvilinear manner with responses at the asymptote being equivalent to turkeys fed the corn-soybean meal control diets. Adequate dietary Thr levels for gain and feed:gain for the 0 to 3 wk period were 0.93% (3.21 g Thr/Mcal ME) and 0.97% (3.34 g Thr/Mcal ME) of diet, respectively. From 3 to 6 wk of age, the level of dietary Thr needed to support adequate BW gain and feed:gain was 0.88% of diet (2.81 g Thr/Mcal ME). The level of dietary Thr needed to support adequate BW gain and feed:gain from 6 to 9 wk of age was 0.77% of diet (2.30 g Thr/Mcal ME). These results indicate that the NRC (1994) estimations of Thr needs up to 9 wk of age are more than adequate.

Animal Feed↗
PubMed1999

Gonadal development and growth of chickens and turkeys hatched from eggs injected with an aromatase inhibitor.

It was the purpose of these experiments to describe gonadal development and posthatching growth of genetic female chickens and turkeys following in ovo injection of the aromatase inhibitor Fadrazole (CGS 16949A) prior to incubation. In ovo injection of Fadrazole (CGS 16949A) resulted in the development of testes-like gonads in the majority of day-old genetic female chickens and turkey poults. Ninety-eight to 99% of these birds have masculine-type male genitalia at 1 d of age. Microscopic examination of the gonads of day-old genetic female chicks hatched from Fadrazole-treated eggs showed the presence of atypical seminiferous tubules in 3 of 18 individuals and the presence of ovarian follicles in 3 of 18 individuals. No germinal elements were seen in 12 individuals. The gonads in the majority (8/11) of day-old female poults from treated eggs showed the presence of atypical seminiferous tubules. Three of 11 individuals had structures characterized as disorganized or degenerate follicles. Between the day of hatch and 6 wk, gonads in an increasing proportion of female chickens from Fadrazole-treated eggs had normal appearing ovarian follicles. A similar trend was seen in the female turkeys between hatch and 12 wk of age. There were no differences in BW of female chickens hatched from Fadrazole-treated eggs and those from control eggs between the day of hatch and 6 wk of age. The pectoral muscle mass and fat pad weights of these birds did not differ. In one experiment, the BW of female turkeys hatched from Fadrazole-treated eggs was significantly greater than that of controls and equal to that of males at 3 and 6 wk of age. Thereafter, both types of females were of equal weight and significantly lighter than males. Fadrazole treatment did not affect pectoral muscle mass of either sex of turkeys.

Adipose Tissue↗
PubMed2000

Rigor mortis development in turkey breast muscle and the effect of electrical stunning.

Rigor mortis development in turkey breast muscle and the effect of electrical stunning on this process are not well characterized. Some electrical stunning procedures have been known to inhibit postmortem (PM) biochemical reactions, thereby delaying the onset of rigor mortis in broilers. Therefore, this study was designed to characterize rigor mortis development in stunned and unstunned turkeys. A total of 154 turkey toms in two trials were conventionally processed at 20 to 22 wk of age. Turkeys were either stunned with a pulsed direct current (500 Hz, 50% duty cycle) at 35 mA (40 V) in a saline bath for 12 seconds or left unstunned as controls. At 15 min and 1, 2, 4, 8, 12, and 24 h PM, pectoralis samples were collected to determine pH, R-value, L* value, sarcomere length, and shear value. In Trial 1, the samples obtained for pH, R-value, and sarcomere length were divided into surface and interior samples. There were no significant differences between the surface and interior samples among any parameters measured. Muscle pH significantly decreased over time in stunned and unstunned birds through 2 h PM. The R-values increased to 8 h PM in unstunned birds and 24 h PM in stunned birds. The L* values increased over time, with no significant differences after 1 h PM for the controls and 2 h PM for the stunned birds. Sarcomere length increased through 2 h PM in the controls and 12 h PM in the stunned fillets. Cooked meat shear values decreased through the 1 h PM deboning time in the control fillets and 2 h PM in the stunned fillets. These results suggest that stunning delayed the development of rigor mortis through 2 h PM, but had no significant effect on the measured parameters at later time points, and that deboning turkey breasts at 2 h PM or later will not significantly impair meat tenderness.

Abattoirs↗
PubMed2000

Serum immunoglobulin G and M concentrations did not appear to be associated with resistance to Pasteurella multocida in a large-bodied turkey line and a randombred control population.

Serum IgG and IgM concentrations in a randombred control line (RBC2) of turkeys and its subline (F), selected long term for increased 16-wk BW were compared. Six-week-old poults were challenged with virulent Pasteurella multocida (1.2 x 10(7) bacteria per bird of serogroup A and serotype 3,4). Sera were collected prior to challenge, and concentrations of IgG and IgM in turkey sera were quantitatively estimated with a Sandwich ELISA using the cross-reactive polyclonal antibodies specific for the chicken Ig isotypes. The F-line turkeys had a higher serum IgM concentration than turkeys from the RBC2 line. There was no significant line difference in IgG concentration. The F line had higher mortality and a shorter number of days to death following challenge with P. multocida than did the RBC2 line. No significant correlation coefficient was found between immunoglobulin isotype concentration in serum and days to death following challenge with P. multocida. The present results suggested that prechallenge IgG and IgM concentrations in serum did not appear to be associated with resistance to P. multocida in a large-bodied turkey line and a randombred control population.

Animal Husbandry↗
PubMed2000

Active immunization with vasoactive intestinal peptide in turkey hens.

Active immunization of turkey hens against vasoactive intestinal peptide (VIP) has been shown to inhibit incubation behavior and to increase egg production in second-cycle hens. The objective of this study was to compare the effect of VIP immunization on first- and second-cycle turkey hens during a 27-wk production period. First- (25-wk-old) and second- (54-wk-old) cycle hens were intermixed, distributed among 16 pens, and subjected to a photoperiod of 6 h of light and 18 h of darkness for 10 wk. The first-cycle hens were divided into two groups: keyhole limpet hemocyanin (KLH)-immunized controls (n = 16) and VIP-immunized (n = 18). Second-cycle hens were divided into four groups: 1) unimmunized controls (n = 19), 2) KLH-immunized controls (n = 18), 3) VIP-immunized (n = 19), and 4) VIP-preimmunized (immunized during first cycle; n = 16). Each hen received four antigen injections beginning the day of photostimulation (4-wk intervals), except for the preimmunized hens, which received three injections beginning 4 wk after photostimulation. The maximum titer of VIP antibodies in first-cycle, second-cycle, and preimmunized hens was 17.2+/-2.2, 20.9+/-2.9, and 21.7+/-3.2%, respectively. After photostimulation, plasma prolactin of first- and second-cycle control hens peaked between 484 +/-105 and 630+/-118 ng/mL. In contrast, prolactin changed very little in VIP-immunized turkeys. The average number of daily nest visits was less in first- and second-cycle VIP-immunized hens (1.68+/-0.23 and 1.09+/-0.15 visits per hen per day, respectively) than in their respective KLH-immunized controls (2.47+/-0.36 and 2.65+/-0.45 visits per hen per day). Expression of incubation behavior was 50.0 and 52.6% in first- and second-cycle control hens, respectively, upon termination of the study. In contrast, only 11.1% first-cycle and 5.2% second-cycle VIP-immunized turkeys exhibited the hormonal and behavioral characteristics of incubating hens. Average weekly egg production of first- and second-cycle VIP-immunized turkeys was similar (3.58+/-0.19 vs. 3.63+/-0.14 eggs per hen per wk). First- and second-cycle control hens laid 2.63+/-0.25 and 2.41+/-0.20 eggs per hen per wk, respectively. The present results show that comparable egg production was attained in first- and second-cycle hens by active immunization with VIP.

Animals↗
PubMed2000

The characterization and incidence of pale, soft, exudative turkey meat in a commercial plant.

Pale, soft, exudative (PSE) turkey meat is a growing problem for industry and has been associated with rapid postmortem pH decline and loss of protein functionality, similar to PSE pork. This study was designed to estimate the incidence of PSE meat in a commercial plant and use response surface methodology to characterize the relationship between pH, lightness (L* value), and water-holding capacity (WHC). One hundred thirty-four turkey breast fillets were selected from the processing line so that 67 had normal color (lightness), and the other 67 were more pale than normal. Fillets were analyzed at time of deboning (1.5 h postmortem) and at 24 h postmortem for color (L* value), pH, drip loss, expressible moisture, and temperature. Additionally, L* values were measured on 2,995 turkey breasts from the processing line to determine the commercial incidence of PSE meat based on color. The pale fillets had significantly lower pH, greater L* value, and less WHC but equal temperature when compared with the fillets with normal color. The L* value and pH were correlated with WHC as measured by expressible moisture, but L* value seems to have more predictive value. By using the L* value range (>53) from the pale-selected fillets as an indication of paleness, approximately 40% of the 2,995 fillets would exhibit poor WHC. These results suggest that PSE meat can represent a significant portion of commercially processed turkey breast meat and that the L* value measurement could be used to sort turkey meat so that PSE type meat could be used in specialized formulations.

Animals↗
PubMed2001

Injection of thyrotrophin-releasing hormone in turkey embryos elevates plasma thyroxine concentrations.

The effectiveness of thyrotrophin-releasing-hormone (TRH) as a secretagogue in turkey embryos was tested. Fertilized turkey eggs were injected with TRH after 24 d of incubation. In an experiment to determine an effective route and dose for TRH administration, it was shown that a single manual injection of 200 microL containing 2.15 microg of TRH, into the air cell or the same injection containing 5.0 microg through the bottom of the egg, was effective in elevating plasma concentrations of thyroxine (T4) 60 min after injection. In a second experiment, 5 microg of TRH in a volume of 200 microL was injected through the bottom of each egg. Injections were performed mechanically into eggs held in a commercial incubator. The injection increased blood plasma T4 for 5 h after a 30-min lag. Eggs from two genetic strains of turkeys were injected in Experiment 3. The TRH elicited a persistent response for 120 min from one strain but resulted in a slightly depressed response from the other, suggesting that subtle differences in the maturation of the hypothalamo-hypophyseal-thyroid axis may exist in commercial strains of turkeys. We concluded that TRH is an effective secretagogue for T4 in 24-d-old turkey embryos.

Animals↗