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

Epitopes for chicken monoclonal antibodies in spleens of selected Japanese quail lines

A line of Japanese quail selected for high plasma cholesterol is highly susceptible to diet-induced atherosclerosis. Lymphocyte epitopes recognized by mouse anti-chicken monoclonal antibodies (c-mAb), TCR-1, TCR-2, TCR-3. CD-3, CD-4, CD-8, and BU-1a/b were reacted with spleens from quail selected for high (HL) and low (LL) plasma total cholesterol and their nonselected controls (CL). Cross reactivity to c-mAb and effect of line and gender were immunohistochemically evaluated. Chicken spleens were positive controls. Quail were immunologically stimulated with either sheep red blood cells (SRBC) or Brucella abortus 2 weeks before spleens were removed. Quail spleen epitopes of all lines recognized TCR-3 and CD-8 c-mAb, but no other c-mAb. Number of reacting cells and staining intensity to the TCR-3 c-mAb were greater in the HL than in the LL regardless of the stimulating Ag or dose used. For the CD-8 c-mAb, there were no differences among lines in birds receiving SRBC. In B. abortus-immunized birds, sex x line interactions indicated that males of the HL and CL had lower responses than females but LL males were not different than females. TCR-3 and CD8 c-mAb may be useful in studying immunological mechanisms for atherosclerosis in Japanese quail.

Changes in distribution of glycosaminoglycans during the progression of cholesterol induced atherosclerosis in Japanese quail

The temporal and spatial distribution and relative concentration of the proteoglycan glycosaminoglycan component were studied during the progression of atherosclerosis in the systemic arteries of Japanese quail selected for cholesterol induced atherosclerosis (CIA). The CIA quail were placed on either control or 0.5% added cholesterol diets at 3 months of age. The major systemic arteries (dorsal aorta, right and left brachiocephalic) were collected at 1- or 2-week intervals over the 10-week period of cholesterol feeding. In the cholesterol fed quail, alcian blue staining of the dorsal aorta showed elevations of glycosaminoglycans in regions of the artery with atherosclerotic plaque, beginning at the 6-week time point. By biochemical analysis, increases in glycosaminoglycan relative concentration was detected at the 10-week time point. In addition to the change in glycosaminoglycan relative concentration and distribution, the cholesterol fed animals also formed foam cells characteristic of atherosclerotic plaques. Therefore, the conclusion reached was that the CIA line of Japanese quail is a valid animal model for the study of alterations in proteoglycan metabolism in atherosclerotic plaques induced by hypercholesterolemia.

Total cholesterol, total triglycerides, and cholesterol distribution among lipoproteins as predictors of atherosclerosis in selected lines of Japanese quail

The proportions of plasma high and low density lipoprotein cholesterol have been linked to inherited tendency for atherosclerosis in humans. Studies were conducted with Japanese quail males from lines genetically selected for high and low TC and a randombred (unselected) control line that were fed 0.0 or 0.5% cholesterol for 12 weeks. Atherosclerotic plaques were more severe in the high than in the low line quail and in those fed cholesterol compared to non-cholesterol-fed quail. Serum TG, TC, VLDLC, LDLC, and HDLC were also higher in the high than in the low line quail and in cholesterol-fed vs. non-cholesterol-fed quail. Significant interactions indicated that TC and LDLC concentrations were more affected by dietary cholesterol in the high line than in the low line. The low line quail maintained higher HDLC and lower LDLC than the high line. Regression and correlation analyses revealed that although VLDLC, LDLC, and TC were significant predictors of atherosclerosis in the high line birds, the TC/HDLC ratio was a better predictor in the low line. The Japanese quail lines used herein represent useful experimental models for studies of genetic differences in atherosclerosis in humans.

Dietary cholesterol effects on plasma and yolk cholesterol fractions in selected lines of Japanese quail

Japanese quail from lines that had been divergently selected for high (HL) or low (LL) plasma total cholesterol and their unselected control line (CL) were fed an all vegetable diet to which 0 or 0.5% crystalline cholesterol were added. Relationships between plasma and yolk cholesterol fractions were examined at 10, 14, and 18 wk of age, which followed 2, 6, and 10 wk consumption of the cholesterol-enriched diet, respectively. Unesterified cholesterol (UC) and cholesteryl esters (CE) in plasma and yolk were analyzed using HPLC. There were no consistent correlations between yolk and plasma for UC, individual CE, total esterified cholesterol (EC), or total cholesterol in the selected lines at ages tested, whether or not 0.5% cholesterol was added to the diet. Cholesterol concentrations in milligrams per gram of yolk and in milligrams per yolk were higher in the HL than the LL at 10 and 14, but not at 18 wk of age. Yolk weights of the HL females increased from 10 to 18 wk of age, whereas those of the LL did not. Cholesterol concentrations in the LL yolks continued to increase over time, however the increases in yolk weight in the HL were not accompanied by proportional increases in cholesterol deposition in the yolk, leading to a dilution of concentration of cholesterol fractions in the HL yolk. Dietary cholesterol increased egg production rate in the selected lines but did not increase the cholesterol content of the yolk.

Atherosclerosis in Japanese Quail males selected for high or low plasma cholesterol

Three lines of Japanese quail males, unselected controls (CL), high response (HL), and low response (LL) lines, selected for plasma total cholesterol for 18 generations, were fed all-plant source, nonatherogenic diets to which 0 or .5% cholesterol were added from 6 to 18 wk of age. Atherosclerotic scores (AS) of aorta of HL birds fed cholesterol were significantly higher than those of LL birds fed cholesterol. Scores of LL fed cholesterol were not higher than LL not fed cholesterol. Fatty infiltration of muscularis and foam cell disruption of elastic fibers were observed in HL males fed cholesterol. In a second experiment, males of the three lines were fed from 6 to 14 wk of age four plant source diets to which were added: 1) 10% glucose monohydrate (cerelose); 2) 10% cerelose + .1% cholesterol; 3) 4% corn oil; or 4) 4% coconut oil. All diets were calculated to be isocaloric and isonitrogenous. Overall, AS of HL and CL males were significantly higher than LL males, but there were no effects of diet for the 56-d feeding period.

Dietary cholesterol and fat saturation effects on plasma esterified and unesterified cholesterol in selected lines of Japanese quail females

Three lines of Japanese quail females, randombred controls (CL), high response (HL), and low response (LL) lines, selected for plasma total cholesterol for 18 generations, were fed all-plant-source, nonatherogenic diets to which 0 or .5% cholesterol were added from 6 to 18 wk of age. In all three lines, plasma cholesterol increased when cholesterol was fed; however, responses were greater in the HL than in the LL line, with CL intermediate. In a second experiment, females of the three lines were fed, from 6 to 14 wk of age, four isocaloric, isonitrogenous plant-source diets to which were added: 1) 10% glucose monohydrate (cerelose); 2) 10% cerelose + .1% cholesterol; 3) 4% corn oil; or 4) 4% coconut oil. Baseline data obtained before feeding experimental diets indicated that the HL had significantly higher plasma total, esterified (EC) and unesterified (UEC) cholesterol than LL and that nonovulating females had higher concentrations of esterified cholesterol than ovulating females. Diets used did not affect cholesterol fractions in the ovulating females, although there were significant differences among lines. Dietary cholesterol significantly increased the ratio of EC to UEC. Sclerotic lesion scores were higher in the HL than the LL birds and in birds fed the coconut oil diet.

Body, abdominal fat, and testes weights, and line by sex interactions in Japanese quail divergently selected for plasma cholesterol response to adrenocorticotropin

Line by sex interactions of BW, abdominal fat, testes weight, and plasma cholesterol were investigated in two Japanese quail lines. High (H-PCHOL) and low (L-PCHOL) quail lines had been developed by 18 generations of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH). Quail were from Generation 28 breeders maintained under a normal environment with no exposure to exogenous ACTH after Generation 18. Quail from growth-selected lines were also used to examine relationships between BW and plasma cholesterol. Body weights of H-PCHOL quail were significantly (P less than or equal to .05) heavier than BW of L-PCHOL quail at 2 and 4 wk of age. However, at 8, 16, and 28 wk BW were similar. Quail from long-term, growth-selected lines were observed to have plasma cholesterol levels similar to those of control lines. Therefore, early BW changes in H-PCHOL and L-PCHOL lines may not be related to plasma cholesterol changes. At 2 and 4 wk, male and female plasma cholesterol values were similar in the H-PCHOL and L-PCHOL lines, however, at 8 and 16 wk males had higher values than females in the H-PCHOL line, and females had higher values than males in the L-PCHOL line. Because interactions were present only after sexual maturity was reached, sex hormones may be involved in the expression of these interactions. Quail in the L-PCHOL line were observed to have significantly (P less than or equal to .05) more abdominal fat and significantly (P less than or equal to .05) smaller testes than quail in the H-PCHOL line.

Plasma and yolk cholesterol levels in Japanese quail divergently selected for plasma cholesterol response to adrenocorticotropin

Studies were conducted to determine the effect of divergent selection for plasma cholesterol response to adrenocorticotropin (ACTH) on the levels and relationships between plasma and yolk cholesterol in Japanese quail. Cholesterol data were obtained in Generation 25, following seven generations of relaxed selection, from birds maintained under a normal environment with no exposure to exogenous ACTH. Levels of plasma and yolk cholesterol were determined at 22 and 28 wk. Plasma cholesterol levels of quail in the low cholesterol line were significantly (P less than .01) lower than levels in the high line at both ages (224 versus 383 and 209 versus 326 mg/100 mL, respectively). In contrast, yolk cholesterol levels were significantly (P less than .01) higher in the low line than in the high line (24.1 versus 21.5 and 21.1 versus 16.9 mg cholesterol/g yolk at 22 and 28 wk, respectively). A significant line by sex interaction was present at both ages for plasma cholesterol with females having higher cholesterol values than males in the low line and males having higher values than females in the high line. A negative relationship was observed between changes in plasma and yolk cholesterol in the selected lines. Greater deposition of cholesterol in the yolk of the line with lower plasma cholesterol indicates that excretion rate may play a role in explaining genetic differences in plasma cholesterol.

Plasma cholesterol responses to the adrenocorticotropic hormone in Japanese quail following eighteen generations of divergent selection

Japanese quail (Coturnix coturnix japonica) lines were divergently selected for plasma cholesterol response to adrenocorticotropin (ACTH). Data for Generations 9 to 18 indicated a greater response in the low (L) line than in the high (H) line, which was contrary to selection responses for the first eight generations. During Generations 9 to 18, selection differentials were greater in the H line; however, heritability estimates were greater in the L line. These data suggest caution in the interpretation of early selection responses for plasma cholesterol. Selection for plasma cholesterol response following ACTH injection also resulted in divergence in plasma cholesterol levels in the H and L lines in the absence of ACTH. Body weights at 31 days were greater in the H line than in the L line, suggesting a possible relationship with the plasma cholesterol level.

Manifestations of social stress in grouped Japanese quail

Physiological manifestations of social stress in stable and unstable (resident and visitor) pairs of adult male Japanese quail (Coturnix coturnix japonica) were compared after 7, 14, 21 and 28 days of regrouping. Unstable pairs had reduced body and relative testes (mg/100 g) weights. Plasma cholesterol was increased significantly in unstable pairs, and adrenal cholesterol was reduced significantly by daily regrouping of unstable pairs. Twelve consecutive days of ACTH treatment (2, 4 or 8 IU/100 g body wt given intramuscularly) to birds in stable pairs induced a decrease in body and relative testes weights. The results were similar to those found in birds subjected to daily regrouping.

Genetic variation of neonatal stress response to reduced temperature brooding in a randombred population of chickens

Chicks from a randombred population were assessed for genetic variation in 1-day body weight and serum corticosterone under two brooding temperatures (26.7 and 32.2 C). Brooding at 26.7 C resulted in lower 1-day body weights and higher corticosterone levels. Heritability estimates (h2) for 1-day body weight were moderately high in both temperature groups but were low for gain in both temperatures. The h2 for corticosterone level from chicks brooded at 26.7 C was moderate, whereas estimates for those brooded at 32.2 were very low. Statistically significant (but low) negative phenotypic correlations were obtained for corticosterone with body weight and gain in both temperature groups. A significant negative genotypic correlation was observed between corticosterone and body weight for chicks brooded at 26.7 C but not for those brooded at 32.2 C. Corticosterone data from the highest and lowest responding sire families revealed a significant response group by temperature interaction. Chicks from the first of two additional hatches showed significant response group differences in serum corticosterone to the reduced brooding temperature. The neonatal serum corticosterone response to cold stress has a genetic basis; however, because there was a negative genotypic correlation between serum corticosterone and body weight, selection for increased corticosterone levels under reduced temperature brooding would likely result in decreased body size.

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.

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).

Microsomal enzyme induction, egg production, and reproduction in three lines of Japanese quail fed polybrominated biphenyls

The sensitivity of three genetic lines of Japanese quail to polybrominated biphenyls (PBBs) was evaluated using criteria of egg production, reproduction, and induction of the hepatic microsomal mixed-function oxidase (MFO) system. Two genetic lines of quail, developed to diverge in their plasma cholesterol response to exogenous adrenocorticotropin (ACTH) (a "Low" line and a "High" line), were compared to a random-bred line ("Random"). ACTH administration caused increases in plasma cholesterol in the Low line that were 15 and 39% below the Random-line values in males and females, respectively, while High-line values were 31% higher in males and 36% higher in females when compared to the respective Random-line values. Hepatic activities of aryl hydrocarbon hydroxylase (AHH) and hexobarbital hydroxylase (HxH) were not significantly influenced by ACTH administration or by genetic line in either sex. PBBs fed at 40 or 80 mg/kg diet for 5 wk resulted in significant increases in hepatic AHH and aminopyrine N-demethylase (APND) activities and cytochrome P-450 concentrations. The induction of AHH, APND, and cytochrome P-450 was significantly less in Low-line males in comparison to Random- and High-line males, while the induction of AHH was less in Low-line females when compared to females from the other two lines, based on covariance analysis. In terms of reproductive parameters, there was a greater adverse effect on egg production at 80 ppm PBBs in Low-line females when compared to the Random and High lines. These data indicate an example in which the biological toxicity of a compound and the induction of a 3-methylcholanthrene-type hepatic enzyme are not directly correlated.

Alteration of lipid metabolism in Japanese quail by feeding oat hulls and brans

Five varieties of oat brans fed for 4 weeks at 2.27% and oat hulls fed at 11.36% in a semi-purified diet containing .5% cholesterol were ineffective in lowering cholesterol levels in the serum of 5-week-old Japanese quail. Oat brans and hulls reduced the level of fat in livers of both males and females. No differences in cholesterol levels were observed between sexes, but hypertriglyceridemia and high liver fat contents were more evident in females. This may be the result of sexual maturation stimulated by a 14L:10D photoperiod.