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Biomedical subjects

H L Marks

Publications and source records attributed to H L Marks.

At least 91 records · Page 5Linked to original sources
PubMed1980

Reverse selection in a Japanese quail line previously selected for 4-week body weight.

After 38 generations of individual selection for high 4-week body weight in a Japanese quail line (T) fed a 20% protein diet containing .2% thiouracil, a reverse selected line (TR) was established by selecting quail in the T line with the lowest 4-week body weight. The TR line was thereafter provided with the same nutritional environment as the T line and selected for low 4-week body weight for 5 generations. The mean 4-week body weights of T line quail increased only slightly from generation 38 through 43. The 4-week body weights of the TR line, however, showed a definite downward trend. The difference in 4-week body weight between the T and TR lines in generation 43 was 15.2 g.

Animals↗
PubMed1980

Divergent selection in Japanese quail for the plasma cholesterol response to ACTH.

Two lines of Japanese quail were divergently selected for high and low plasma cholesterol levels after three daily injections with 2 IU of adrenocorticotropen (ACTH)/100 g of body weight. Plasma cholesterols were obtained at 31 days of age, just before the first injection, and at 34 days of age, after the last injection. After eight generations of selection, the plasma cholesterol level after ACTH injections in the high line was 34% greater than the level in the control line, whereas the low line level was approximately 14% less than that in the control. Selection differentials were significantly greater in the high line than in the low line. The realized heritability for plasma cholesterol before ACTH treatment calculated by regression of progeny on mid-parent was .25 in the high line and .16 in the low line.

Adrenocorticotropic Hormone↗
PubMed1980

Growth, feed intake, and feed conversion of dwarf and nondwarf broiler-type chickens.

Feed intake and feed conversion patterns of meat-type dwarf (dw) and normal contemporaries were investigated in two trials, with the Athens-Canadian randombred line used as the base population. Dwarf chickens consumed significantly less feed than normal ones the first day posthatching and in all subsequent observation periods. The deviation in body weight ratios and feed intake ratios between lines were greatest during week 1. These data indicate that the action of the dw gene is present at hatching and exerts at least part of its influence through feed intake or appetite. Feed conversion ratios (feed/gain) were lower in dwarf birds than in normal birds during week 1, whereas overall differences across 8 weeks were small. The difference in relative growth rate between genotypes was greatest during week 1; by week 4, relative growth rates were similar.

Animal Feed↗
PubMed1980

An analysis of skeletal muscle response to selection for rapid growth in Japanese quail (Coturnix coturnix Japonica).

A line of Japanese quail selected for high body weight at 4 weeks of age (P line) was compared to an unselected control (C) line at 10, 23 and 56 days of age. The increase in the weight of the pectoralis major and supracoracoideus muscles in the P line was paralleled by an increase in total DNA, RNA and protein content of the muscles when compared to comparable age C line. DNA, RNA and protein concentrations and RNA/DNA and protein/DNA ratios were similar between lines within age. Greater muscle mass in the P line was accomplished primarily through an increase in the total number of muscle nuclei rather than through an increase in DNA unit size. Ca2+-activated myosin ATPase, total phosphorylase and succinic dehydrogenase enzyme activities were similar between lines and across ages in the pectoralis major and supracoracoideus muscles. The semimembranosus muscle possessed 59% more alpha fibers and only 7% more beta fibers in the P line when compared to the C line. Semimembranosus alpha fiber diameters were not significantly different between lines within age, while beta fiber diameters were significantly greater in the P line. Estimated beta fiber contribution to total semimembranosus muscle cross sectional area revealed no significant difference between lines within age. There was a significant increase in the length of the femur and humerus in the P line when compared to C line within age, indicating that some of the increased muscle weight of the P line quail was due to an increase in muscle length in addition to an increase in muscle cross-sectional area.

Adenosine Triphosphatases↗
PubMed1979

Genetic resistance to aflatoxin in Japanese quail.

Progress was rapid in attempts to develop lines of quail resistant to acute aflatoxicosis induced by oral dosing with aflatoxin. After five generations of selection, 8- and 11-fold differences were present in mortality between two selected lines and their respective control lines. These quail lines should be of value in investigating the physiological basis of resistance to aflatoxin.

Aflatoxins↗
PubMed1979

Growth rate and feed intake of selected and nonselected broilers.

The relative growth rates and feed intake patterns of selected and nonselected broiler populations were investigated in three trials. The relative growth rate of the selected populations was approximately twice the relative growth rate of the nonselected population during week 1, whereas by week 4 the rates of the selected and nonselected populations were similar. The percentage deviation between populations in feed intake was higher than the percentage deviation in body weights for week 1 in all trials. Feed intake strongly influenced the growth rate of selected and nonselected populations, especially from 3 to 8 weeks of age. The selected populations had superior feed efficiency from 0 to 4 weeks compared to the nonselected population, however, differences between populations from 4 to 8 weeks were not significant.

Animals↗
PubMed1978

Growth curve changes associated with long-term selection for body weight in Japanese quail.

Four quail lines were utilized to investigate growth patterns in quail. Three of these lines (P, T and S) had previously undergone long-term selection for high 4-week body weight, while line C was maintained as a nonselected control. Quail progeny from generation 37 and 38 breeders were fed diets containing 28% and 20% protein. Within each trial, the diet/line treatments were replicated 3 times with 12 quail per subclass. Body weight measurements suggested that the growth of all lines was best approximated by the logistic growth curve model. When fed a 28% protein diet the age at maximum growth (point of inflection) of selected lines was 4 to 6 days earlier than the corresponding age of controls. Similar rates of gain after 4 weeks of age between selected and control lines suggested that mechanisms influenced by selection for 4-week body weight in quail operate only during the period prior to the age at selection with little or no residual effect.

Analysis of Variance↗
PubMed1977

Divergent selection for yolk cholesterol in laying hens.

1. Lines were selected for divergence in yolk-cholesterol concentration for three and four generations in the Cornell Controll (Leghorn) and Athens-Canadian (AC) (meat-type) randombred populations respectively. Selection was based on both individual and family records. 2. Cholesterol values were obtained from two consecutively laid eggs when birds were 28 weeks of age. The yolks of eggs from individual hens were pooled and analysed for cholesterol content by the colorimetric assay of Zlatkis et al. (1953) on the "fat extract" obtained by a modification of the procedure of Folch et al. (1956). 3. The largest differences between high and low lines (1-27 and 1-38 mg cholesterol/g yolk) were observed in the last generation of selection. There was evidence of a lack of response in the low lines. Realized heritability estimates obtained by dividing the difference between high and low lines by half the cumulative selection differential ranged from 0-11 to 0-25 in the AC population and from 0-21 to 0-25 in the Leghorn population. Realised estimates on a within-line bassis suggest that selection for yolk cholesterol is effective only in the upward direction.

Animals↗
PubMed1976

Effect of citrinin, a mycotoxin produced by Penicillium citrinum, on laying hens and young broiler chicks.

Citrinin fed to mature laying hens at levels of 0, 50, and 250 mug/g. of diet for three weeks had no effect on body weight, feed consumption, egg production, egg weight or egg shell quality. A moderate diarrhea occurring about three days after feeding 250 mug. citrinin/g. of diet was observed. However, the diarrhea subsided once the birds were returned to a normal diet. Young broiler chicks were fed a diet containing either 0, 62.5, 125, 250, or 500 mug. citrinin/g. of diet from hatching to three weeks of age. Body weight was decreased by the 500 mug/g. level whereas all levels of citrinin resulted in enlarged kidneys and an improvement in feed conversion when compared to control values. There was also a slight dose-related increase in liver size. The 250 and 500 mug./g. levels resulted in a dose-related increase in water consumption accompanied by an acute diarrhea. Dietary citrinin had no effect on serum protein, glucose, cholesterol, uric acid, calcium, potassium and sodium concentrations or packed cell volume.

Animal Feed↗
PubMed1976

Growth of broilers and quail fed Fusarium (Gibberella zeae)-infected corn and zearalenone (F-2).

There were no effects in commercial broilers after the long term ingesting of Fusarium-infected corn supplying 1, 10, and 30 p.p.m. zearalenone (F-2) in diets. Average gain and feed conversion were similar in all treatment groups. In the first feeding trial the average body weights were higher for males than for females, but the differences were not significant. Purified F-2, 30 P.P.M., was fed to broilers and no chronic effects were observed. Differences in mean body weights, between dietary treatments in the two Japanese quail lines were small and not significant after 4 weeks on diets containing 0, 10, and 25 p.p.m. F-2 from Fusarium infected corn.

Animal Feed↗
PubMed1976

Influence of Fusarium-infected corn and F-2 on laying hens.

Diets containing either Fusarium-infected corn supplying 25 and 100 p.p.m. of F-2 (zearalenone) or purified F-2 at these levels did not adversely influence the reproductive performance of laying hens. In trial 1, no deleterious effects were observed for 20- and 36-week body weights, age at first egg, egg weight, albumen height, shell deformation, fertility or hatchability when Fusarium-infected corn was fed to 20-week-old pullets for 28 days. Percent hen-day egg production of birds fed Fusarium-infected corn supplying 25 and 100 p.p.m. of F-2 was superior (P less than or equal to 0.5) to egg production of nontreated controls. In trial 2, three replications of ten adult Leghorn hens were evaluated under five dietary treatments: (1) 16.7% protein basal; (2) basal plus Fusarium-infected corn (25 p.p.m. of F-2); (3) basal plus 25 p.p.m. of (purified) F-2; (4) basal plus Fusarium-infected corn (100 p.p.m. of F-2); (5) basal plus 100 p.p.m. of (purified) F-2. Difference between dietary treatments for 14-day pre-treatment, treatment and post-treatment periods were nonsignificant for 42- and 44-week body weights, egg production, egg weights, fertility and hatchability. Body weights of chicks from hens fed F-2 diets were not significantly different from those of chicks from hens fed the basal diet.

Animals↗
PubMed1975

Relationship of embryonic development to egg weight, hatch weight, and growth in Japanese quail.

Relationships between egg, embryo, hatch, two-week and four-week body weights of three quail lines differing in growth rate were investigated. Two of the quail lines had previously undergone 29 generations of selection for increased four-week body weight, and the third line was a nonselected control. Selected lines produced heavier eggs, larger 10 to 11 day embryos, and larger chicks. Percent embryo weights were similar for all three lines indicating that correction for egg size eliminated differences in embryo weight. Percentages of hatch weights of selected lines were significantly (P less than .01) larger than comparable percentages in the control line. Correlations between egg and embryo weights were of low magnitude but correlations between egg and hatch weights were large (.7 to .8). Mean regression coefficients for four-week body weight on egg weight were 5.11 and 2.67 g. in trials 1 and 2, respectively. Relationships between egg, embryo, hatch, and body weights of Japanese quail appeared to be of the same general magnitude as those observed in the domestic fowl.

Animals↗