Biomedical subjects

J Brake

Publications and source records attributed to J Brake.

At least 37 records · Page 2Linked to original sources

PubMed1989

Effects of CGA-72662 (Larvadex) in turkeys during rearing and reproduction.

Turkeys were fed CGA-72662 (Larvadex) at treatment levels of 0, 500, 1,000, and 2,000 mg/kg diet from hatch to 16 wk of age, when the 500 mg/kg level was reduced to 250 mg/kg because of a significant reduction in feed intake. All diets continued through 40 wk of age. Body weight, feed consumption, livability, egg production, fertility, hatchability, and progeny performance were examined. Turkeys fed a treatment level of 2,000 mg CGA-72662/kg diet exhibited reduced growth rate and feed consumption prior to sexual maturity and decreased fertility and poult weight after sexual maturity. Necropsies suggested that the kidney was the primary site of lesions at the 1,000 and 2,000 mg/kg diet treatment levels. The kidneys were characterized as enlarged, nodular, and cystic, containing urate deposits and areas of necrosis. These data indicate that dosage levels of CGA-72662 at 250 mg/kg diet produced no deleterious effects on growth, feed consumption, egg production, fertility, hatchability, livability, or progeny performance.

Age Factors↗

PubMed1989

Effects of lighting program during the growing period and dietary fat during the laying period on broiler breeder performance.

In two experiments, broiler breeders were grown in either of two lighting regimens, fed diets without added fat, and then fed diets with or without 5% added poultry fat during the subsequent laying period. In Experiment 1 half the birds were subjected to decreasing daylength using daylight (800 lx) and half were subjected to 9 h of incandescent light (20 lx) to 20 wk of age. In Experiment 2 the lighting regimen was either an 8-h photoperiod supplied by daylight (800 lx) or an 8-h photoperiod supplied by incandescent light (20 lx) to 20 wk of age. Added dietary fat produced significantly higher egg weight (Experiments 1 and 2), egg production (Experiment 2), and significantly lower fertility and hatchability of fertile eggs (Experiments 1 and 2). Short photoperiods (8 or 9 h) provided by incandescent light produced significantly higher fertility (Experiments 1 and 2) and hatchability of fertile eggs (Experiment 2), and significantly lower egg specific gravity, shell percentage (Experiment 1), egg weight, and eggshell weight (Experiment 2). Effects on fertility may be related to higher female body weight during lay due to daylight rearing or added fat, or relative changes in light intensity at photostimulation.

Analysis of Variance↗

PubMed1988

Effect of adrenocorticotropin and dietary ascorbic acid on the graft-versus-host reaction capacity of chickens.

Two trials using the splenomegaly assay were conducted to assess the effects of adrenocorticotropin (ACTH) and dietary ascorbic acid (AA) on the ability of chickens to mount a graft-vs.-host reaction (GVHR). Broiler chicks served as blood donors. Birds received AA at levels of 0, 150, or 300 mg/kg of feed (ppm). At 6 wk of age, donor birds from each AA group received either three intramuscular injections of ACTH in gelatin at 12-h intervals, comparable injections of the gelatin, or no injections. Thirteen-day-old Single Comb White Leghorn embryos served as recipients. Two recipient embryos per donor were injected in a chorioallantoic vein with either whole blood (Trial 1) or saline-washed and reconstituted blood cells (Trial 1). Eggs were further incubated for 6 days, at which time the embryos were killed and each spleen excised. Relative spleen weights were expressed as milligrams of spleen/100 g embryonic body weight. Significant differences in relative spleen weight or donor plasma corticosterone (CS) levels did not occur in Trial 1. In Trial 2, regardless of AA treatment, relative spleen weights of embryos that received blood cells from donors treated with ACTH were significantly lower than controls. Donor CS was significantly lower in birds that received ACTH. These results indicate that, when washed and reconstituted blood cells are injected into recipients and donor plasma CS is decreased, GVHR capacity is suppressed in ACTH-treated donors.

Adrenocorticotropic Hormone↗

PubMed1988

Relationship of time of feeding and strain to egg shell quality and hatchability in broiler breeders.

The relationship of feeding time to egg production, egg weight, egg shell quality, fertility, and hatchability was examined in two trials. Slow and fast-feathering strain Hubbard females were used in Trial 1 and slow-feathering strain Arbor Acres females were used in Trial 2. Feeding times of 0800 or 1300 h throughout the laying periods were compared. Slow feathering females in Trial 1 exhibited significantly increased egg weight and significantly decreased percentage shell when compared with fast-feathering females. Feeding at 1300 h increased significantly egg specific gravity, egg shell weight, and percentage shell in Trials 1 and 2. Significant interactions of feeding time and strain occurred in Trial 1 with respect to fertility and hatch of all eggs set. Feeding at 1300 h increased fertility and hatch of all eggs set in fast-feathering hens but the opposite occurred in slow-feathering hens in Trials 1 and 2. Within slow-feathering hens, hatch of fertile eggs was decreased by 1.7% (Trial 1) and 1.5% (Trial 2). The results show that afternoon feeding that provides calcium intake near the time of egg shell calcification decreased significantly hatchability in eggs from two slow-feathering strains of females but not in eggs from a fast-feathering strain. These results suggest that altering time of feed intake can decrease hatchability.

Animals↗

PubMed1988

Effect of cortisol on cutaneous basophil hypersensitivity to phytohemagglutinin in chickens.

Three independent trials were conducted to determine if cutaneous basophil hypersensitivity (CBH) to the mitogen phytohemagglutinin (PHA-P) was affected by the injection of cortisol in broiler cockerels. Trials 1 and 2 were similar, and Trial 3 imposed a period of heat stress in combination with cortisol. At 6 wk of age, chicks were injected intramuscularly with 2 mg of cortisol in a corn oil vehicle/500 g body weight at 48, 36, 24, and 12 h prior to challenge with PHA-P. Controls received an equal amount of corn oil on the same schedule. Each chick received .05 mL of PHA-P (100 micrograms) in the right wattle and an equal volume of saline in the left wattle. The CBH was assessed by measuring the thickness of wattles at various times from 0 to 48 h after challenge with PHA-P. Wattle indices were calculated. Birds were necropsied at 48 h post-PHA-P, and bursa of Fabricius, spleen, and both adrenals excised and weighed. Cortisol produced a significantly greater CBH response in Trials 1 and 2 as indicated by higher wattle indices at 48 h and at 6 h in Trial 3. Regression analysis indicated significantly greater intercepts for the cortisol responses in Trials 1 and 3 and a significantly greater linear component for the cortisol response in Trial 2. Body weights and relative bursa and spleen weights were reduced significantly by cortisol, whereas relative adrenal weights were increased significantly in Trials 2 and 3. These data indicated that cortisol enhanced CBH to the mitogen PHA-P in broiler cockerels. This is in contrast to reported immunosuppressive effects of other glucocorticoids.

Animals↗

PubMed1987

Postmolt performance of laying hens molted by high dietary zinc, low dietary sodium, and fasting: egg production and eggshell quality.

Single Comb White Leghorn (SCWL) hens, 65 weeks of age, were assigned to one of four dietary treatments: fasting to a body weight loss of 34% (FAST), administration of a diet containing less than or equal to 500 ppm sodium for 42 days (Lo Na), administration of a diet containing 20,000 ppm zinc for 10 days (Hi Zn), and a control (CON) diet. The hens were subjected to two photoperiod treatments, those receiving 17 hr (17-hr) of light per day throughout the 32-week experiment and those restricted to 8 hr of light per day for the first 42 days followed by a .5 hr/day increase until 17 hr was reached. Egg production and mortality were recorded daily. Feed consumption, feed conversion, and livability were determined weekly. Beginning on Day 56, eggs were collected at 28-day intervals for determination of egg weight, egg specific gravity, and shell weight. During the molt phase (1 to 6 weeks), the 17-hr light day significantly increased egg production, feed consumption, and decreased feed conversion (kg/doz) across all groups when compared with the 8-hr light/day treatments, but FAST treatments consumed identical amounts under both light treatments. From 7 to 32 weeks during the postmolt phase, egg production was significantly increased and feed conversion decreased by the FAST and Hi Zn treatments relative to CON, Lo Na treatment was intermediate. Feed consumption was significantly higher for the FAST treatment. Overall, there were not significant effects on egg production, feed consumption, and feed conversion.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Effects of eggshell cuticle removal and incubation humidity on embryonic development and hatchability of broilers.

The effects of eggshell cuticle removal and two levels of incubation humidity 28.3 C [50% relative humidity (RH)] and 30.0 C (55% RH) wetbulb temperature (WB) on embryonic mortality and hatchability were determined from broiler hatching eggs laid during 38, 42, 48, and 54 weeks of age. Variables measured were: egg weight loss during the first 17 days of incubation, hatch at Days 19.5 and 20.5 of incubation, hatch of fertile eggs, stage of embryonic mortality, and chick weight at 21.5 days of incubation. Day 0 to 17 percentage egg weight loss was increased when the incubation humidity was lowered and the loss was greater than that observed after cuticle removal. A greater percentage of chicks hatched on Day 19.5 at 28.3 C than at 30.0 C WB. The percentage hatch of 38-week fertile eggs was improved at the higher humidity; the higher humidity also decreased late dead and increased pipped embryonic mortalities. Cuticle removal decreased early dead and increased late dead mortality. At Week 38 cuticle removal and lower humidity resulted in a decrease in chick weight at 21.5 days of incubation. For Weeks 42, 48, and 54 combined, pipped mortality was increased by higher humidity and late dead mortality was increased by cuticle removal. Water loss from the egg was increased by cuticle removal or by lowering incubation humidity from 30.0 C to 28.3 C WB, or by both, but lowering humidity was more effective. Changes in humidity and cuticle removal may affect vital gas exchange to different degrees.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Effect of lighting program and nutrition on reproductive performance of molted single comb White Leghorn hens.

Two adjoining rooms in a light-tight, fan-ventilated, insulated house were used for a study involving 320 Single Comb White Leghorn hens, 60 wk of age, placed two per cage. These hens were subjected to an induced molt which compared two lighting programs, two molt rations, two levels of total sulfur amino acids (TSAA), and two levels of ascorbic acid (AA) in a factorial arrangement. There were four treatments. Treatment 1 compared the Washington lighting program (WSU), consisting of an 8-h light photoperiod for 28 days beginning 7 days before fast with the North Carolina program (NCSU), consisting of a 24-h light photoperiod for 7 days prior to fast followed by 12 h light/day for 21 days. After 28 days, light duration was increased to 16 h/day in stages for both programs. Treatment 2 consisted of feeding cracked corn (CC) or 16% protein molt ration (MR) for 2 weeks: Treatment 3, feeding of 14% layer mash with either .60% or .65% TSAA; and Treatment 4, addition of either 0 or 50 ppm AA to the 14% layer mash. After molting, egg production was increased in the NCSU lighting program and .65% TSAA treatments. Feed conversion was improved by the NCSU lighting treatment. Deaths were fewer in diets with 50 ppm AA. Egg weight, specific gravity, and shell weight were not affected by any treatment. A significant light X molt diet interaction occurred due to better performance of MR birds compared with CC birds in the NCSU lighting program, whereas on the WSU lighting program, CC produced better performance. These data indicated that combining features of various molt programs may not produce optimum results.

Animal Husbandry↗

PubMed1987

Influence of presence of perches during rearing on incidence of floor laying in broiler breeders.

Broiler breeders were reared in an all-litter blackout house on an 8-h photoperiod either in the presence or absence of perches (28 cm per bird) from hatching to 20 wk of age. The configuration of the perches resembled that on the standard 12-hole nest boxes in the curtain-sided slat-litter laying house to which birds were moved at 20 wk of age. Birds reared in the presence of perches exhibited a significantly reduced incidence of floor egg laying during each of two experiments. Birds reared with perches laid 3.6 vs. 8.6% floor eggs (Experiment 1) and 9.7 vs. 12.6% floor eggs (Experiment 2) when compared with birds reared without perches. The opportunity to learn perching behavior during rearing influences laying and nesting behavior in broiler breeders.

Animals↗

PubMed1987

Effect of lighting program and nutrition on feather replacement of molted single comb White Leghorn hens.

This experiment concerned the induced molt of 320 60-wk old Single Comb White Leghorn hens placed two per cage in two adjoining sections of a light-tight, fan-ventilated poultry building. Treatments compared were: 1) lighting program: Washington (WSU) vs. North Carolina (NCSU). The WSU program used 8 h light/day for 28 days beginning 7 days before fast. The NCSU program used continuous light for 7 days prior to fast, followed by 12 h light/day for 21 days. The light portion of the photoperiod was then increased in steps in both treatments to 16 h. 2) Molt diet: cracked corn (CC) vs. 16% protein molt ration (MR) for 14 days. 3) Laying diet. A 14% protein mash calculated to contain .60% or .65% total sulfur amino acids (TSAA) or ascorbic acid (AA) at 0 or 50 ppm added to the laying mash. Day 1 was designated as the first day of photoperiod modification. Primary and secondary feather loss and subsequent primary feather growth were all significantly increased by the WSU light program at 56, 84, and 112 days. Total and average growth of new primaries was significantly increased by MR at 56 days and total primary feather growth by .65% TSAA at 112 days. No effects due to AA were observed. Photoperiod had the greatest effect on molt per se, with MR and .65% TSAA increasing early and late growth, respectively.

Animal Nutritional Physiological Phenomena↗

PubMed1987

Characterization of different hematological responses during molts induced by zinc or fasting.

Single Comb White Leghorn hens were induced to molt by complete fasting for 11 days (FAST) or feeding a layer ration that contained 20,000 ppm zinc as zinc oxide for 11 days (ZINC). In both cases hens lost approximately 30% of their initial body weight. A control (CON) group was maintained. At 4, 8, 12, 18, and 42 days after initiation of the treatments, total erythrocyte numbers (TRBC), percent packed cell volume (PCV), mean corpuscular volume, hemoglobin (Hb), mean corpuscular hemoglobin (MCHb), and mean corpuscular hemoglobin concentration (MCHC) were determined. Erythrocytes were characterized as reticulocytes, intermediate Stage VII erythrocytes, or mature Stage VIII erythrocytes. The FAST hens exhibited significantly increased PCV through 18 days, which was not exhibited by ZINC hens. The FAST treatment increased TRBC on Days 8 and 12 and decreased TRBC on Day 42 while ZINC decreased TRBC on Day 4 and increased TRBC on Day 12. The FAST hens exhibited decreased Hb on Day 42, as reproduction resumed. Both ZINC and FAST hens exhibited decreased MCHb and MCHC on Day 12. Percentages of reticulocytes were decreased at Day 4 by FAST and increased at Days 8 and 18 by ZINC. Stage VII erythrocytes were decreased on Days 4 and 12 in FAST hens whereas ZINC hens exhibited a decrease on Day 4 and an increase on Days 8 and 18. Concomitantly, FAST hens exhibited an increase in Stage VIII erythrocytes on Days 4 and 12, whereas an increase on Day 4 and decreases on Days 8 and 18 were observed in ZINC hens.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Effect of adrenocorticotropin and dietary ascorbic acid on cutaneous basophil hypersensitivity to phytohemagglutinin in chickens.

Two trials were conducted to assess the effects of adrenocorticotropin (ACTH) and dietary ascorbic acid (AA) on cutaneous basophil hypersensitivity (CBH) to phytohemagglutinin (PHA-P) in chickens. Broiler chicks received AA at levels of 0, 150, or 300 mg/kg of feed (ppm) continuous from hatching. At 6 to 7 wk of age, birds from each AA group received either 2 IU ACTH/100 g of body weight, 4% gelatin, or no ACTH or gelatin injections. Injections were given 12 h prior to, at the time of, and at 12 and 24 h after an intradermal wattle injection with PHA-P. Responses to PHA-P were determined as wattle indices. Injections of ACTH reduced body weight gain in both trials and decreased relative bursa weight in Trial 1. Injections of ACTH and dietary AA increased plasma cholesterol in both trials. Peak CBH wattle response occurred at 24 h post PHA-P injection. Injections of ACTH decreased mean wattle index at 18 and 36 h post PHA-P injection in Trial 1 and 18 and 24 h post PHA-P injection in Trial 2. The addition of AA ameliorated the ACTH-mediated suppression of CBH in a dose-related manner.

Adrenocorticotropic Hormone↗

PubMed1987

Effects of adrenocorticotropin and dietary ascorbic acid on delayed type hypersensitivity to human gamma globulin in chickens.

Three trials were conducted to assess the effects of adrenocorticotropin (ACTH) and dietary ascorbic acid (AA) on delayed type hypersensitivity (DTH) to human gamma globulin (HGG) in chickens. Broiler chicks received AA at 0, 150, or 300 mg/Kg of feed (ppm) continuously from hatching, were sensitized at 5 wk of age to HGG emulsified in complete Freund's adjuvant, and 2 wk postsensitization, were challenged with an intradermal injection of HGG into a wattle. Birds from each AA group received ACTH at either HGG sensitization, challenge, or both. There were uninjected controls and a vehicle control group, which received gelatin at both sensitization and challenge. The ACTH and gelatin injections were given at 12-h intervals beginning 12 h prior to HGG. Responses to DTH were determined as wattle indices. In all three trials, birds that received ACTH at challenge exhibited a DTH response at 18 and 24 h postchallenge that suppressed, compared with that of controls. Birds that received ACTH at sensitization had a greater wattle response than that of birds that received ACTH at challenge, and this effect was enhanced by dieting AA. In Trial 2, birds that received ACTH at sensitization had a greater wattle response at 18 h post HGG challenge than that of controls. Total leucocyte numbers were unaffected; however, heterophil:lymphocyte ratios were lower in birds that received ACTH at sensitization than in birds that received ACTH at challenge and birds that received ACTH at challenge had fewer lymphocytes. Whether given at challenge or at sensitization, ACTH decreased plasma AA when measured at those times. The 300 ppm level of AA increased plasma AA concentration. Adrenal gland and wattle AA levels were unaffected; however, spleen AA concentration was lower in birds given ACTH at challenge.

Adrenocorticotropic Hormone↗

PubMed1985

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↗

PubMed1985

Effects of caponization on body weight, atherosclerosis, and cardiovascular variables in hypertensive and hypotensive turkey lines.

Effects of caponization and blood pressure selection on serum lipids, severity of atherosclerosis, body weight, hematocrit, and relative ventricular weight in hypertensive and hypotensive lines of turkeys were evaluated in two trials. At 8 weeks of age, half the turkeys from each line were caponized. Body weights, blood pressure, and blood samples were obtained from each treatment at 8, 20, and 30 weeks of age. A total of 56 and 72 birds were used in Trials 1 and 2, respectively. Birds were necropsied at 30 weeks of age. Hypertensive turkeys had significantly greater serum cholesterol and total lipid than hypotensive turkeys only at 30 weeks of age in Trial 1. Lower relative ventricular weights were observed in hypotensive turkeys within both trials. Hypertensive birds exhibited a more severe degree of atherosclerosis and higher relative heart weight than hypotensive turkeys. Caponization significantly increased total serum lipid only at 20 weeks of age in Trial 2. Average body weight of caponized turkeys was significantly lower (1.2) than the control turkeys at 30 weeks of age. Caponized turkeys exhibited lower relative ventricular weight in Trial 1 but not Trial 2 and an increase in blood pressure only in Trial 2. Caponization suppressed body weight, decreased hematocrit values, and had no significant effect upon plaque severity. The presence or absence of male sex hormones had virtually no effect on proposed atherogenic stimuli thereby suggesting another mechanism by which the female is afforded a higher degree of protection.

Animals↗

PubMed1985

Cellular changes in the spleen during an induced molt.

Agranulocytes proliferated in spleens of molted hens and both leucocytic and erythrocytic cells exhibited decreased numbers of pyknotic nuclei. These changes were confined to the period when the reproductive tract regressed. It was concluded that there is a relationship between the physiological status during an induced molt and the cellular population of the spleen.

Animals↗

PubMed1985

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↗

PubMed1984

Physiological profile of caged layers during one production year, molt, and postmolt: egg production, egg shell quality, liver, femur, and blood parameters.

A longitudinal study of a flock of Single Comb White Leghorn pullets was initiated at 19 weeks of age (preproduction) and continued through a production year, a forced molt, and for 4 months of postmolt production. A representative sample of hens was obtained at 12-week intervals during the first year and at subsequent selected times. Liver lipid, femur weight, femur volume, femur density, egg weight, shell weight, percent shell, milligrams shell/square centimeter of shell surface area, serum calcium, serum phosphorus, and serum alkaline phosphatase were determined. Percent hen-day production peaked at 90% and then declined by .6 to .7% each week during the first production year. After molting, percent hen-day egg production peaked at 80% and declined .9% per week over the subsequent 20 weeks. Egg weight increased continually during the first production year. Shell weight was greatest immediately postmolt; thereafter it declined. Shell thickness was greatest at 31 weeks of age and declined throughout the first year. After molting, the shell thickness of 83-week-old hens was similar to values of hens about 37 weeks of age. Serum calcium and phosphorus of laying hens were influenced by age, feed intake and environmental temperature. The lowest values occurred during hot weather. Liver lipid was lowest in nonlaying hens (17 to 20%) and was approximately 42% of dry weight in laying hens. Femur density was greater in laying than nonlaying hens.

Alkaline Phosphatase↗