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Biomedical subjects

P Y Hester

Publications and source records attributed to P Y Hester.

At least 55 records · Page 3Linked to original sources
PubMed1989

Plasma insulin and glucagon levels and leg measurements of lame turkeys.

As insulin is a regulator of cartilage and bone growth, plasma levels of pancreatic hormones were determined in 41 lame male turkeys with long bone distortion and 42 control toms without leg deformities. Blood samples were collected 3.5 h following the removal of feed and then 1 h after the return of feed. The day following blood collection, toms, 119 days of age, were slaughtered to obtain leg measurements. Body weight, width, and length of the tarsometatarsus, presence of tibial dyschondroplasia (TD) lesions, pancreas weight, and plasma glucose did not differ between lame and control turkeys. A significantly greater proportion of growth plates of the tarsometatarsus was closed in the control as compared to the lame turkeys. Pancreas weight relative to BW was significantly greater for lame as compared to control turkeys. Plasma insulin was undetectable in both fasted lame and control turkeys. When feed was returned to the turkeys, plasma insulin concentrations were significantly lower in lame compared to control turkeys. The return of feed had no effect on plasma glucagon levels in controls, but concentrations were decreased significantly in lame birds. These data suggest that the regulation of plasma insulin and glucagon may be altered in lame turkeys perhaps contributing to the cause of long bone distortion.

Analysis of Variance↗
PubMed1987

Effect of light intensity, litter source, and litter management on the incidence of leg abnormalities and performance of male turkeys.

Two trials were conducted to evaluate the performance of male turkeys reared in either a low or high intensity lighting regimen. Turkeys were also subjected to the following four litter treatments: hardwood shavings intensively managed; hardwood shavings unmanaged; rice hulls intensively managed; and rice hulls unmanaged. Male turkeys reared in high intensity light (20 lx) had significantly heavier body weights, poorer feed to gain ratios, shorter tarsometatarsal bones, earlier growth plate closure, heavier testes, and were less active during the times of behavioral observations than male turkeys reared in low intensity light (2.5 lx). The width of the tarsometatarsal bone, mortality, and the incidence of leg abnormalities and tibial dyschondroplasia were unaffected by lighting. Poor litter conditions or type of litter (hardwood shavings vs. rice hulls) had no effect on the performance of male turkeys.(u3)

Animals↗
PubMed1986

Comparison of two lighting regimens and drinker cleaning programmes on the performance and incidence of leg abnormalities in turkey males.

Turkey males subjected to a low intensity step-down (LISD) lighting programme showed significantly heavier body weights after 20 weeks of age and significantly better feed conversions after 14 weeks of age compared with males reared in a high intensity step-up lighting (HISU) programme. Although both nonchilled and chilled carcase weights were higher, the dressing percentages were lower for males of the LISD lighting regimen. Males of the HISU lighting programme had significantly fewer leg abnormalities, shorter tarso-metatarsi, lighter drumstick weights, and lighter tibia weights. Males on the HISU lighting programme from 15 to 19 weeks of age had larger testes; however, after 20 weeks of age they were larger in males on the LISD lighting regimen. Cleaning and disinfecting the drinking troughs daily rather than weekly had no effect on any production variable measured.

Animals↗
PubMed1986

Relationship of high intensity step-up lighting to bone ash and growth plate closure of the tarso-metatarsus in turkeys.

The reduced lameness observed in turkeys reared in a high intensity step-up (HISU) lighting programme as compared to a low intensity step-down (LISD) lighting regimen cannot be explained by differences in the inorganic matrix of the bone, because the proportions of bone ash, bone ash calcium, and bone ash phosphorus did not differ between lighting programmes. At 17 weeks of age, there was a significant difference in the proportion of closed growth plates in males reared on the HISU programme rather than on LISD lighting. These results support the hypothesis that HISU lighting reduces lameness by promoting earlier growth plate closure of long bones.

Animals↗
PubMed1986

Performance of White Leghorn hens in response to cage density and the introduction of cage mates.

Hens reared at densities of 344 and 516 cm2/bird produced significantly fewer hard-shelled (HS) and shell-less (SL) eggs than hens reared at a density of 1031 cm2/bird. Soft-shelled (SS) egg production was not affected by the density treatment. A decline in ovulation rate would account for the decrease in total hen-day production in response to the higher density treatments. To determine if the introduction of new cage mates would cause hens to lay fewer eggs with poorer shell quality, the performance of hens with visitors was compared with those with nonvisitors. Visitors were introduced monthly for 13 months. Visitors vs. nonvisitors showed no significant difference with regard to HS, SS, and SL egg production, feed efficiency, mortality, egg weight, and specific gravity.

Animals↗
PubMed1985

Phosphorus phase feeding and uterine and isthmus mucosal enzymes and minerals in relation to soft-shelled and shell-less egg production.

The relationships among phosphorus phase feeding, egg shell quality, and the activities and concentrations of several enzymes and minerals in the uterine and isthmus mucosae of hens at the time of oviposition were investigated. During the first 8 months of production (Phase 1), layer diets contained .3, .5, or .7% available phosphorus. Between 9 and 12 months of production (Phase 2), dietary available phosphorus was either increased or decreased by .2% phosphorus, or was left unchanged. No significant differences due to Phase 1 diets were demonstrated for hard-shelled (HS), soft-shelled (SS), or shell-less (SL) egg production, livability, egg weight, or specific gravity. Phase 2 diets had no significant effect on SS or SL egg production, livability, or egg specific gravity; however, decreasing dietary phosphorus reduced egg weight. Levels as high as .9% had no effect on specific gravity or HS egg production, while .1% dietary phosphorus was detrimental to HS egg production and feed consumption. No significant differences due to dietary available phosphorus or egg type (SS vs. HS) were demonstrated for uterine or isthmus mucosal enzyme activities or mineral contents, with one exception. Higher inorganic phosphorus concentrations were found in the uterus of HS egg layers when compared to levels in the uterus of SS egg layers and the isthmus of HS and SS egg layers. Acid phosphatase and carbonic anhydrase activities, and total calcium levels were significantly higher in the isthmus than the uterus, while alkaline phosphatase and pyrophosphatase activities, and inorganic phosphorus levels were significantly higher in the uterus than the isthmus.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1985

Antibodies to the alpha-subunit of insulin receptor from eggs of immunized hens.

Simple methods for the generation, purification, and assay of antibodies to the alpha-subunit of insulin receptor from eggs of immunized hens have been described. Chicken antibodies against the alpha-subunit inhibit insulin binding to the receptor and stimulate glucose oxidation as well as autophosphorylation of the beta-subunit. Thus the properties of chicken antibodies are very similar to those of antibodies found in human autoimmune diseases and different from rabbit antibodies obtained against the same antigen.

Adipose Tissue↗
PubMed1984

Influence of sex-linked feathering phenotypes of parents and progeny upon lymphoid leukosis virus infection status and egg production.

Data were collected on egg production, livability, lymphoid leukosis virus and antibody incidence, and hemagglutinin response to sheep red blood cells for slow- and fast-feathering female progeny from slow- and fast-feathering dams with known lymphoid leukosis virus infection status. Analyses of these results indicate that when the offspring or the dams are of the slow-feathering type, the offspring experience an increased rate of horizontal infection. This infection seemingly leads to an immunologically tolerant condition with an inability to produce specific lymphoid leukosis virus antibodies, thereby allowing the viremia to persist. This immunologically tolerant condition, which also occurs in the progeny of virus positive dams due to congenital transmission, is associated with depressed egg production performance. However, a hypothesized lack of immunological competence was not found in the hemagglutinin response to sheep red blood cells late in life. Our results suggest that fast-feathering progeny of slow-feathering dams may also be adversely influenced by increased congenital infection from their dams.

Animals↗
PubMed1984

Relationship of plasma corticosterone and adrenal cholesterol and corticosterone to the production of soft-shelled and shell-less eggs.

Two experiments were conducted to determine if plasma corticosterone and adrenal cholesterol and corticosterone levels differed among hens that laid soft-shelled (SS) or shell-less (SL) eggs when compared with hard-shelled (HS) egg layers. For Experiment 1, four groups of White Leghorn hens were bled at 22 to 34 weeks of age in the morning (0600 to 1200 hr) and at 66 to 74 weeks of age in the morning and evening (1500 to 1900 hr). Group 1 consisted of birds that had just laid SS or SL eggs, whereas Group 2 hens had SS or SL eggs in utero. Groups 3 and 4 represented hens with HS eggs in their uteri and hens that had just laid HS eggs, respectively. For Experiment 2, adrenal cholesterol and corticosterone levels were assayed in high (18+%) and low (0%) incidence SS plus SL egg layers at 73 and 78 weeks of age. Both younger and older hens that laid SS or SL eggs in the morning had similar plasma corticosterone concentrations when compared to HS egg layers. Morning plasma corticosterone levels were significantly higher among hens that laid an egg when compared to hens with eggs in utero, regardless of whether the egg was SS, SL, or HS. However, plasma corticosterone levels of hens producing SS or SL eggs in the evening were significantly higher than levels of hens that laid evening HS eggs. Evening HS egg layers demonstrated the oviposition related peak in plasma corticosterone, but concentrations were 1 ng/ml higher among the evening SS or SL egg layers. Adrenal cholesterol and corticosterone concentrations were similar between high and low incidence SS plus SL layers at either age. It is postulated that evening production of SS or SL eggs is a consequence of elevated plasma corticosterone.

Adrenal Glands↗
PubMed1983

The effect of dietary lysine levels on performance and meat yields of White Pekin ducks.

Four trials were conducted to determine the effects of dietary lysine levels ranging from .70 to 1.00% on performance and yield of different carcass components of male and female White Pekin ducks. Dietary lysine had no significant effect on weights or feed efficiencies at market age of 48 or 49 days; however, significant differences were obtained with yields of component parts for the males in Trial 2 and the females in Trial 3. In these trials, overall meat yields were significantly better for males fed levels of lysine between .80 and .95% and for females fed a lysine level of .90%.

Animals↗
PubMed1983

Effects of high intensity step-up and low intensity step-down lighting programs on the incidence of leg abnormalities in turkeys.

Two trials were conducted to determine if a high intensity (20 lx) step-up lighting program would decrease the incidence of leg abnormalities in turkeys. The step-up lighting regimen was compared to a low intensity (2.5 lx) step-down lighting program. Toms were used in Trial 1 and both sexes were employed in Trial 2. Body weight, feed/gain ratio, and mortality of toms of Trial 1 did not differ significantly between lighting regimens. The incidence of leg deformities and the length of the tarsometatarsal bone were significantly decreased, whereas plasma androgen and testes weights were increased for toms of Trial 1 in the high intensity step-up lighting. The same trends were apparent for toms of Trial 2 with the exceptions that feed/gain ratios were adversely affected and testes weights were significantly lower for toms of the high intensity step-up lighting program. The performance of hens in the high intensity step-up lighting program of Trial 2 was affected adversely; however, incidence of leg abnormalities and length and width of the tarsometatarsus responded in the same manner as with toms. The results of this study indicate that a high intensity step-up lighting program can significantly reduce leg weakness problems in turkeys. Possible explanations for light stimulation reducing the incidence of leg abnormalities are through increased exercise and shortening of long bones.

Animals↗
PubMed1983

The relationship of dietary levels of phosphorus to the production of soft-shelled and shell-less eggs.

The relationship among available levels of dietary phosphorus (.2, .3, and .4%) and the production of soft-shelled (SS) and shell-less (SL) eggs was investigated in 864 White Leghorns of a commercial strain. An 11-month performance profile included hen-day production of hard-shelled (HS), SS, and SL eggs, feed consumption, livability, egg weight, and specific gravity. Percent HS egg production and feed consumption were significantly lower and egg specific gravity was significantly higher among hens consuming the .2% available phosphorus diet when compared to hens consuming the .3 or .4% available phosphorus diets. The level of available phosphorus in this study did not affect significantly hen livability or the production of SS or SL eggs. Five hours (HS egg in uterus) or 15 hr (SL egg in uterus) prior to expected oviposition time, 1 ml of a 200 mM phosphate solution was injected into the brachial vein (i.v.) or the uterus (i.u.) of hens observed to lay consistently HS eggs. Injections i.v. did not alter expected oviposition time when either a HS or SL egg was in the uterus, but i.u. injections induced premature oviposition when a SL egg was in utero. The concentrations of inorganic phosphorus and total calcium in the plasma and uterine fluid of hens that laid a high or low incidence of SS + SL eggs were determined 5 hr after the egg entered the uterus. Uterine fluid inorganic phosphorus and total calcium and plasma inorganic phosphorus levels of the high and low incidence groups were not significantly different. However, plasma total calcium was significantly higher among high incidence SS + SL layers when compared to low incidence SS + SL layers at this time during the ovulatory cycle.

Animals↗
PubMed1983

A comparison of methionine sources for broiler chickens fed corn-soybean meal diets under simulated commercial grow-out conditions.

Two experiments, involving 5,760 birds each, were conducted under simulated commercial grow-out conditions to determine the relative response of broiler chicks to two supplemental levels each of DL-methionine (DL-MET), L-methionine (L-MET), and methionine hydroxy analogue-free acid (MHA-FA) fed on an equimolar basis in corn-soybean meal diets. MHA-FA was shown to support 49-day weight gains comparable to those of chicks fed DL-MET, and both sources were superior to L-MET in this regard. However, there were no significant differences due to MET sources in the efficiency of feed utilization. When compared to basal-fed chicks, birds fed supplemental L-MET, DL-MET, or MHA-FA had elevated plasma free MET levels, whereas cyst(e)ine and taurine concentrations were not affected by dietary treatment. There were no effects of diet on either mortality or the incidence of leg abnormalities. The results of these studies suggest that MHA-FA is an acceptable source of MET for broiler chicks fed corn-soybean meal diets from day-old to market weight.

Animals↗
PubMed1982

Plasma levels of cholesterol and testosterone in White Leghorn hens that laid soft-shelled and shell-less eggs.

Plasma concentrations of cholesterol and testosterone were determined in White Leghorn hens that had just laid soft-shelled (SS) or shell-less (SL) eggs and compared to those that laid hard-shelled (HS) eggs. Hens were bled at two different ages, at 22 to 34 and 66 to 74 weeks of age. Blood samples were collected in the morning hours (0600 to 1200 hr) for both age groups with an additional evening bleed (1500 to 1900 hr) for the 66 to 74-week-old hens. Both plasma constituents were higher in hens that laid SS or SL eggs when compared to those which laid HS eggs, but differences were statistically significant only for the 66 to 74-week-old hens bled in the morning hours. The results of this study indicate that elevated levels of testosterone and its precursor, cholesterol, may be related to the production of eggs with little or no shell calcification.

Age Factors↗
PubMed1981

The effect of varied brooding temperature on the incidence of leg weakness and subsequent performance of turkeys.

Male Nicholas turkeys were used in a study designed to determine the effects of high, moderate, and low brooding temperature on the occurrence of leg abnormalities during a subsequent 20 week grow-out period. Performance data were also obtained. There were no significant differences among the poults brooded under any of the three temperature regimens in the incidence of leg weakness or mortality. Body weights and feed/gain ratios measured at 2, 5, 10, 15, and 20 weeks of age were similar regardless of brooding temperature.

Animals↗
PubMed1981

The effects of chronic handling on the incidence of leg abnormalities and several blood parameters in turkeys.

Twelve hundred day-old Nicholas toms were randomly distributed among 47 pens as part of two experiments designed to evaluate the effects of chronic handling on leg weakness and several blood parameters. From 5 until 19 weeks of age, one half of the birds, designated as the handled group, was subjected to physical examination once each day, 5 days a week, in an effort to detect the development of leg abnormalities. They were also removed from their pens and weighed at 5, 10, 15, and 20 weeks of age. The remaining birds, referred to as nonhandled, were exposed to the minimum amount of human contact necessary for proper management. Experiment 1 involved only birds in the handled group. When a leg weakness was detected, the afflicted bird and a healthy control from the same pen were bled. Determinations were made of packed cell volume, hemoglobin concentration, total leukocyte count, and the plasma levels of uric acid, inorganic phosphate, calcium, alkaline phosphatase activity, testosterone, and corticosterone. Lame birds were found to have significantly higher total leukocyte counts and plasma corticosterone concentrations than healthy controls, the other parameters being unaffected. Experiment 2 was performed using both handled and nonhandled birds, 19 weeks of age. Lame and healthy subjects from each group were selected. Blood parameters identical to those in Experiment 1 were measured; it was found that lame birds had significantly higher plasma corticosterone levels than healthy controls and that chronic handling caused significant decreases in packed cell volume, uric acid, alkaline phosphatase activity, and corticosterone. Handling did not affect the incidence of leg weakness or mean final body weight.

Animals↗