Biomedical subjects

H L Marks

Publications and source records attributed to H L Marks.

At least 73 records · Page 4Linked to original sources

PubMed1984

Growth hormone, thyroxine, and triiodothyronine levels of Japanese quail selected for four-week body weight.

Plasma growth hormone (GH), triiodothyronine (T3), and thyroxine (T4) levels were compared in four lines of Japanese quail (C,P,T, and S) from 1 to 4 weeks of age in two experiments. Lines P and T were derived from line C by 59 generations of selection for high 4-week body weight. Line P was selected under the same nutritional regimen as line C (28% protein) while line T was selected under a restricted protein (20%) ration containing .2% thiouracil. Line S was developed as a subline from T by continuing the thiouracil stress but with the birds on 28% protein ration. Marked differences in body weight have resulted with C line birds being lightest followed by T,S, and P, line birds, respectively. There were significant line, age, and experiment differences in GH. Levels decreased with age in all lines. The GH levels of the largest and smallest (P and C) lines were higher than those of the intermediate-sized birds at 1 and 2 weeks of age but not thereafter. Levels of T3 decreased with age in Experiment 1, but in Experiment 2 they increased from 1 to 2 weeks and declined thereafter. In general, T3 levels of all three selected lines were lower than the control line with S and T being lowest and P intermediate.

Aging↗

PubMed1984

Plasma constituents and body weights of Japanese quail (Coturnix coturnix japonica) selected for twelve generations for plasma cholesterol responses to adrenocorticotropin.

Japanese quail were selected bidirectionally over 12 generations for plasma cholesterol (PC) responses to adrenocorticotropin (ACTH). In addition to the selected trait, plasma corticosteroids (PCS), triglycerides (PT), and glucose (PG) were measured before and after 3 daily injections of ACTH. The quail were also weighed at 31 days of age. By the 12th generation of selection, when measurements were expressed as deviations from the randombred control (C) line from which the selected lines had been derived, there was a difference in PC of approximately 55% between the high response (HR) and the low-response (LR) lines. Pre-ACTH PCS levels increased in all three lines over generations; however, relative to the C line, there was no difference between selected lines. The 3 days of ACTH injection depressed PCS levels. Relative to the C line, pre- and post-ACTH levels of PT were higher in the HR line than in the LR line, and the LR line declined linearly over generations. Levels of PG did not change over generation in the selected lines; however, pre-ACTH levels of PG tended to be higher in the LR line than in the HR line in all generations. Body weights of the HR line at 31 days remained almost exactly the same as the C line, but those of the LR line declined linearly over the 12 generations of selection. These studies demonstrated that the PC response to ACTH was moderately heritable (h2 approximately equal to .20).

Adrenal Cortex Hormones↗

PubMed1984

Body size, reproductive behavior, and fertility in three genetic lines of Japanese quail.

The influences of body size on early locomotor activity, intermale aggression, mating behavior, fertility, and hatchability were studied in three lines of Japanese quail. Lines P and C originated from the same base population with P selected for high 28-day body weight and C maintained as a randombred population. Line S was a randombred line unrelated to P and C. Line P quail were larger than both C and S quail, which were similar in size and had proportionally larger cloacal glands than those from the P line. The P and S males were more aggressive than C males. Although there was no difference among the three lines for number of attempted matings, C and S males completed more matings and had better mating efficiency and fertility than P males. The P females received more attempted matings than C and S females, but S females completed more matings, resulting in higher mating efficiency. Fertility tended to be lower in P females, while hatchability of fertile eggs was similar across all lines. The effect of body size on reproductive performance is discussed in the context of genetic homeostasis.

Animals↗

PubMed1984

The roles of protein level and diet form in water consumption and abdominal fat pad deposition of broilers.

Two experiments were conducted to investigate the possible relationship of water intake and water/feed ratios in explaining abdominal fat changes associated with changes in dietary protein level and diet form. In Experiment 1, day-old male chicks from two commercial broiler stocks were fed diets containing 26, 22, and 17% protein from 0 to 19 days of age. Chicks fed the 26% protein diet consumed more water, had higher water/feed ratios, and had less abdominal fat than chicks fed lower protein diets. Chicks fed the 22% protein diet were intermediate to the 26 and 17% protein treatments in water consumption, water/feed ratios, and abdominal fat. In Experiment 2, day-old male chicks from two commercial broiler stocks were fed a diet in either mash or crumbled form from 0 to 20 days of age. Chicks fed crumbles had heavier body weights, consumed more feed and water, and had more abdominal fat than birds fed the mash diet. Superior body weights of birds fed the crumbled diet appeared to be due to higher relative growth rates immediately after hatch.

Abdomen↗

PubMed1984

Agglutinin responses to Salmonella pullorum in Japanese quail selected for plasma cholesterol response to adrenocorticotropin and a model describing the dynamics of the response.

Japanese quail from the S16 generation of lines selected for high (HR) and low (LR) plasma cholesterol response to adrenocorticotropin (ACTH), and the randombred control line (C) from which the selected lines had been derived, were immunized with a heat-killed Salmonella pullorum antigen. Plasma from blood samples taken at 0,5,8, and 12 days postimmunization was titered for total agglutinin levels. A quadratic equation and its first derivative, calculated for each bird, produced mean values by line for maximum titers, mean day of maximum titer, and rate of titer decline. Results indicated that the LR line had significantly lower titers than the HR or C lines but that the HR line reached maximum titer later than the LR line. The rate of titer decline was fastest in the C line.

Adrenocorticotropic Hormone↗

PubMed1984

Intakes of feed and water following restriction in selected and nonselected broilers.

Consumption following a 24-hr withdrawal from feed or water was examined in selected and nonselected broilers from 0 to 10 days of age and in low body weight (LW), high body weight (HW), and HW X LW (F1) progeny from 120 to 132 days of age. In posthatch trials, body weights of feed-restricted (FR) and water-restricted (WR) selected broilers decreased more rapidly than comparable treatments in nonselected broilers. Feed intake of ad libitum control treatments in both genotypes was significantly greater than feed intake of FR and WR treatments. Nonselected birds had a greater ability to compensate for feed deprivation than selected birds, and there appeared to be no differences between genotypes with regard to ability to compensate for water deprivation. The LW birds and HW X LW progeny (F1) had greater ability than HW birds to compensate for both feed and water restriction. Feed consumption on days of water restriction was not as severely reduced as was water consumption on days of feed restriction. It was concluded that water intake is more dependent on the availability of food than is food intake on the availability of water at 120 days in the LW and HW lines.

Animals↗

PubMed1984

Effect of the dw gene on growth, plasma hormone concentrations and hepatic enzyme activity in a randombred population of chickens.

The effect of the dw gene on growth, lipid deposition, plasma hormone concentration, and enzyme activity in a randombred population of chickens was studied. The reciprocal crosses were examined as well as purebred dwarf and normal populations. Body weight, carcass fat, plasma growth hormone (GH), triiodothyronine (T3), thyroxine (T4), hepatic malic enzyme (ME) and citrate cleavage enzyme (CCE) activities were determined at 0, 2, 4 and 6 weeks. Body weights of dwarf birds were less than normal birds and, unexpectedly, Dwdw males had greater body weights than DwDw males. Percent carcass fat was greater in dwarf birds in comparison to phenotypically normal birds. All males carrying the dw gene had greater fat pad weights than homozygous normal males. The dw- females from cross 3 had less abdominal fat than cross 4 Dw- females, while dw- females from the dwarf parental mating had fat pad weights similar to Dw- females. Plasma T4 levels were elevated in all birds carrying the dw gene in comparison to normal birds. Plasma T3 levels were depressed in all birds carrying the dw gene versus normals, although the T3 levels of Dwdw males were intermediate to dwdw and DwDw males. The homozygous dwarf progeny exhibited elevated GH levels versus normals and Dwdw males exhibited GH concentrations intermediate to dwdw and DwDw males. Malic enzyme activity was lower in all birds carrying the dw gene, while CCE activity was not effected by genotype.

ATP Citrate (pro-S)-Lyase↗

PubMed1983

Effect of dietary aflatoxin concentration on the assessment of genetic variability of response in a randombred population of chickens.

The effect of graded levels of dietary aflatoxin on the assessment of genetic variability of body weight and gain and plasma protein response was tested utilizing the Athens-Canadian randombred population of chickens. Dietary aflatoxin was administered at levels of either 0, 1.25, 2.50 or 5.0 microg/g of diet ad libitum from 7 to 21 days of age to progeny from 58 sire families. Twenty-one-day body weights, gain and plasma protein concentration were used to assess the variation in response.-The administration of increasing levels of aflatoxin resulted in a dose-related decrease of gains and plasma protein concentrations. Plasma protein concentrations were significantly higher among males than females within the control group; however, this difference was reversed as the severity of the aflatoxin challenge increased. Heritability estimates for all responses increased as the level of aflatoxin administered increased. This change was most notable for total plasma protein concentration. Phenotypic correlations for plasma protein concentration and growth measurements tended to diminish with increasing levels of aflatoxin. A similar trend was noted for the genetic correlations; however, a moderate correlation between growth responses and plasma protein response was detected in the 5.0-microg/g aflatoxin treatment group. Genetic correlations were calculated for the same characters between the different levels of aflatoxin. Regardless of which aflatoxin challenges were compared, a very high genetic correlation for 21-day body weight and 7- to 21-day gain was estimated. This variation in growth potential in the toxic environment paralleled that observed in the control environment but at a lower plane. Genetic correlations for plasma protein response across aflatoxin levels diminished as the difference between the levels of aflatoxin administered increased. Plasma protein concentration in the control environment was positively correlated with plasma protein response in groups fed a low level of aflatoxin, but negatively correlated when an aflatoxin challenge of 2.5 microg/g or more was given, suggesting that selection for aflatoxin resistance using plasma protein response as a selection criterion should be made under an aflatoxin stress environment.

Aflatoxins↗

PubMed1983

Selection for body weight at eight weeks of age in dwarf and normal meat-type chickens originating from a common control population background.

A study was conducted to evaluate responses to selection for 8-week body weight in normal and dwarf meat-type broiler lines originating from the same nonselected randombred population. Following three generations of selection, normal and dwarf dams were mated to males from a commercial broiler stock to compare strain cross performance of progeny from the two dam groups. The mean realized heritabilities across four generations for 8-week body weight, estimated by dividing the cumulative responses by the cumulative selection differentials, were .69 for normal lines and .59 for dwarf lines. Realized estimates from regression of population means on cumulative selection differentials were .78 +/- .10 and .74 +/- .02 for normal lines and .70 +/- .14 and .59 +/- .19 for dwarf lines. Although these estimates were not significantly different, realized heritabilities were consistently greater in normal than in dwarf lines across generations. The smaller heritability estimates observed in dwarf lines were compensated for by larger selection intensities (i), which resulted in similar selection responses in 8-week body weight for normal and dwarf genotypes. The fertility of normal and dwarf females mated to commercial broiler males was identical. However, the hatchability of fertile eggs was approximately 10% higher for dwarfs than for normal females. Body weights (8-week) of male progeny from dwarf dams mated to commercial males were 3% smaller than comparable males from normal dams. There were no differences between 8-week body weights of female progeny from normal and dwarf dams mated to commercial males.

Animals↗

PubMed1983

The relationship of altered water/feed intake ratios on growth and abdominal fat in commercial broilers.

Three trials were conducted to investigate the relationship of changing water/feed ratios on growth rate and abdominal fat levels of two genetic lines. Water/feed intake ratios were elevated by feed restriction programs (skip-a-day and 70% restriction) from 0 to 4 days of age. Following return to ad libitum feed, compensatory gains were observed in body weights, and the elevated water/feed ratios declined to levels similar to that of controls. The addition of up to 2.4% dietary salt resulted in increased water/feed intake ratios without reductions in feed intake. Early body weights of birds receiving diets containing high levels of salt were larger than body weights of birds receiving the control diet. Peak differences in body weights occurred at 4 days and were larger in males than females. Feed efficiency from 0 to 4 days was higher for birds receiving high salt diets than for birds receiving the control diet. Decreasing the high salt levels resulted in reduced water/feed ratios to levels comparable to controls. Small differences were observed in abdominal fat between the two genetic lines. Abdominal fat weights were significantly (P less than or equal to .05) reduced (17 to 28%) in both lines when birds were fed a 2.4% salt diet. Although abdominal fat weights were similar between sexes, differences in body weights resulted in significant (P less than or equal to .05) differences between males and females in percent abdominal fat. Data indicated that high water/feed intake ratios may be associated with reduced abdominal fat.

Adipose Tissue↗

PubMed1983

Thyroid activity of selected, nonselected, and dwarf broiler lines.

Growth rates and serum thyroid hormone concentrations were compared in two trials. In Trial 1 Athens-Canadian (AC) randombred chickens (nonselected) were compared with commercial broiler line chickens (selected). Trial 2 involved the same nonselected and selected lines and a sex-linked dwarf line developed from the same background as the AC population. Selected line birds were heavier than nonselected line birds and nonselected line birds were heavier than dwarf line birds from 1 through 8 weeks of age. Overall, the selected line had lower 3,5,3'-triiodothyronine (T3) concentrations than the nonselected line. No significant differences in thyroxine (T4) concentrations were observed between selected and nonselected lines. The dwarf line had lower T3 and higher T4 concentrations than the other lines. The data suggest a lower rate of T4 deiodination in the dwarf line.

Animals↗

PubMed1982

An analysis of satellite cell content in the semimembranosus muscle of Japanese quail (Coturnix coturnix japonica) selected for rapid growth.

Transverse sections of the semimembranosus muscle of a control (C) line of Japanese quail and of a line (P) selected for high body weight at 4 weeks of age were observed for nuclear content. The two lines were sampled at 4 days posthatching and at 4 weeks of age. The relative number of satellite cells decreased from 4 days to 4 weeks of age. The total number of satellite cells, however, appeared to increase as muscle length increased; this relation was not influenced by line effects. It was concluded that the greater number of nuclei in the longer fibers of P-line quail was principally the consequence of a greater mitotic rate in the satellite cells of this line compared to the C-line quail.

Age Factors↗

PubMed1982

Composition and muscle cellularity of Japanese Quail after selection for high body weight under an optimal or suboptimal nutritional environment.

The purpose of this study was to determine if the compositional and cellularity changes associated with selection for rapid growth rate in an optimal and suboptimal nutritional environment were similar. The P-line Japanese quail had undergone long-term selection for high 4-week body weight and received a 28% protein diet. The unselected C-line quail received the same diet. T-line quail were selected by the same criteria as P-line quail but received a 20% protein diet containing .2% thiouracil. Body weights and muscle weights of P- and T-line quail were similar at 10 days of age. At 56 days T-line body weight and muscle weights were intermediate between C- and P-line quail, but whole body composition of P- and T-line quail was similar. The P- and T-line quail possessed a greater apparent number of muscle fibers than C line quail. Total muscle DNA content was lower in T-line muscles compared to P-line muscles at 56 days of age. No differences within age were observed among lines of myofiber diameter, fiber type composition, for concentrations of DNA, RNA and protein, or for protein/DNA and RNA/DNA. At 10 days the weight, length and diameter of the humerus and femur bones were greatest in T-line quail; these same parameters were intermediate between C- and P-line quail at 28 and 56 days of age. It was concluded that selection for rapid growth rate per se caused apparent fiber number and fiber length to increase while the effect of suboptimal nutritional environment was not evident until after 10 days of age. Selection under suboptimal conditions as exercised in this study prevented expression of the maximum number of muscle DNA units.

Animals↗

PubMed1982

Stability of hemoglobin gene frequency in randombred chicken and quail populations.

The stability of hemoglobin polymorphism in a randombred chicken and a randombred Coturnix quail population was studied by comparing the frequencies of known hemoglobin mutant genes after several generations of maintaining nonselected randombred populations. The current gene frequency of .053 in the chicken population was similar to the .060 gene frequency determined 13 generations ago. A gene frequency of .069 was observed for the mutant hemoglobulin in the quail population compared to a .042 frequency 15 generations ago.

Animals↗

PubMed1982

Growth hormone and prolactin levels in nonselected and selected broiler lines of chickens from hatch to eight weeks of age.

Plasma growth hormone and prolactin levels were measured in two lines of commercial broiler chickens (lines 2 and 4) and two nonselected randombred broiler lines (lines 1 and 3). The body weights of the 4 lines differed by only a few grams at day of age but by 1 week of age the selected lines were 60-80 g heavier than the unselected lines. At 8 weeks body weights of the selected lines exceeded 2000 g while the unselected lines were approximately half this. At all bleeding times between 1 and 8 weeks of age GH levels of both nonselected lines were significantly higher than those of both selected lines. GH levels of the two selected lines did not differ from each other, nor in general did GH levels of the unselected lines differ from each other. In both experiments GH levels of the unselected lines increased between 1 and 3 weeks then dropped week by week. In contrast, GH levels of the selected lines were rather stable from 1 to 3 weeks and gradually declined thereafter. Prolactin levels of the unselected lines tended to exceed those of the selected lines, but the differences only achieved significance at 2-3 weeks of age. GH levels at various ages were found to be significantly correlated to relative growth at different time periods. These significant correlations were generally positive and occurred most often in the selected broiler lines. Overall analysis of variance showed a significant relationship between GH levels and growth in Expt. 2, but not in Expt. 1.

Aging↗

PubMed1981

Role of water in regulating feed intake and feed efficiency of broilers.

Three trials were conducted to investigate the influence of restricting feed and water intake levels of a fast-growing selected broiler line to the same feed and water intake levels of a nonselected line and to investigate the relationship of water/feed ratios to feed conversion (feed/grain) ratios. The water intake of birds from the selected line on feed restriction was similar to that of birds from the selected line not on feed restriction from 1 to 14 days. However, restriction of water intake of selected line birds resulted in feed intake similar to that of nonselected line birds. From 1 to 14 days, feed conversions of the feed-restricted selected line birds were similar to those of the selected line birds not on feed restriction. Feed conversions of the water-restricted selected line birds were similar to those of nonselected line birds. The maximum deviation in water intake between the selected and nonselected lines was observed before the maximum deviation in feed intake between the two lines; and the maximum deviation in feed intake was observed before the maximum deviation in body weight. Data presented indicate that high water/feed ratios are associated with low feed/gain ratios.

Animal Feed↗

PubMed1980

Aflatoxin susceptibility of selected and control Japanese quail lines.

1. The influence of aflatoxin on growth and mortality of diverse lines of quail was studied in five trials. 2. Feeding 5 or 10 micrograms aflatoxin/g diet from 4 to 7 weeks of age resulted in significant decreases in body-weight gain in all lines. 3. Similar gains for all treatments during the third week of feeding indicated that body weights were reduced only during the first two weeks. 4. Crop intubation with 4 or 8 mg aflatoxin/kg body weight resulted in different mortality patterns for the selected and control quail lines.

Aflatoxins↗

PubMed1980

Protein polymorphism in quail populations selected for large body size.

The polymorphism of five enzyme loci (amylase, alkaline phosphatase, albumin, for 4-week body weight was compared to that of the unselected control line (C). Three loci in the C line and two in the P line demonstrated polymorphism. Plasma amylase was separated into six bands and zymograms were classified on the basis of these bands into nine phenotypes. Three of the nine types were of relatively high activity and six were of relatively low activity. All nine types were found in the C line, whereas, all birds of the P line had only the most active type. Two alkaline phosphatase alleles (Akp-2B and Akp-2C) were segregating in the C line. Gene frequencies of alkaline phosphatase for the Akp-2B allele were 0.92 in the C line and 1.00 in the P line. Two albumin alleles (AlbQ1 and AlbQ2) were segregating in both populations. Gene frequencies for the AlbQ1 allele were 0.74 in the C line and 0.81 in the P line. Two red cell esterase-D alleles (Es-DF and Es-DS) were segregating in both populations. The gene frequency for the Es-DS allele (0.61) was higher than that of the Es-DF allele in the C line. In the P line the frequency of the Es-DF allele was higher than that of the Es-DS allele. Heterozygosities of the C and P lines were estimated as 0.2258 and 0.1560 respectively. The relative inbreeding coefficient of the P line, calculated from heterozygosities was 0.31.

Alkaline Phosphatase↗