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Biomedical subjects

J C Rogler

Publications and source records attributed to J C Rogler.

At least 37 records · Page 2Linked to original sources
PubMed1982

Performance at two rearing temperatures of White Leghorn lines selected for increased and decreased survival under heat stress.

Body weight and percent mortality resulting from heat stress at 40.6 C were determined on two lines selected for resistance and susceptibility to heat stress by the Florida Agricultural Experiment Station and reared from 5 to 9 weeks of age in two temperatures, 32.2 C and 21.1 C. The resistant line was significantly smaller in body weight at 5 and 9 weeks of age and had less gain in weight from 5 to 9 weeks of age than the heat susceptible line. Birds reared in the cold environment had significantly larger 9-week body weight and gain from 5 to 9 weeks of age than those reared in the hot environment. At 9 weeks of age the birds were heat stressed at 40.6 C and 50% relative humidity. The heat resistant line had a significantly lower percent mortality than the heat susceptible line. Birds reared at 21.1 C had a significantly greater percent mortality when heat stressed than those reared at 32.2 C. No interaction occurred between the selected lines and the temperatures in which they were reared for percent mortality or any of the body weight traits. Comparison with other experiments involving the same base population from which the Florida lines were selected indicated that the response to selection for resistance was greater than that to selection for susceptibility. It is suggested that natural selection for heat resistance could be responsible for the asymmetry of response. An estimate of the genetic correlations (rG) was derived as the geometric mean of the ratios of correlated to direct responses. The estimate of rG between body weight gain from 5 to 9 weeks of age and percent mortality under heat stress was .16.

Animals↗
PubMed1981

Response to selection at two temperatures for fast and slow growth from five to nine weeks of age in poultry.

Cornell Control White Leghorn chicks were grown in a common environment to five weeks of age and selected for fast and slow gain in body weight from five to nine weeks of age at two temperatures, 21.1 degrees (cold) and 32.2 degrees (hot), during which time a constant 50% relative humidity was maintained. All lines were tested each generation in both temperature environments. Selection continued for four generations, with a second replicate started six weeks after the first replicate in each generation. In the hot environment, a 20% reduction (104 g) in five-to-nine-week weight gain was found. The responses to selection for fast and slow growth were symmetrical except in the first generation, when an outbreak of bronchitis confounded selection for body weight with selection for disease resistance and allowed little gain in the slow lines. No genotype-by-environment interactions were found, indicating that selection in either direction in either selection temperature produced equal responses in either test temperature. This suggests that any interactions observed between the growth of strains in tropical vs. temperature climates must be due to some difference between these environments other than the temperature differences studied.

Animals↗
PubMed1981

Influence of phenylalanine and lysine deficiencies on thyroid morphology in the chick.

A study was conducted to investigate the effects of dietary phenylalanine and lysine deficiencies on thyroid morphology in chicks fed crystalline amino acid diets. Both mean follicle diameter and epithelial cell height were significantly reduced in birds fed either of the deficient diets as compared with controls. These results agree with previous studies on serum T4 and T3 concentrations where the effects of an amino acid deficiency were general and not limited to precursors of thyroxine.

Animals↗
PubMed1980

Effects of dietary phenylalanine and tyrosine on circulating thyroid hormone levels and growth in the chick.

Studies were conducted to investigate the effects of a phenylalanine-tyrosine deficiency on serum thyroid hormone concentrations and growth in chicks from 0 to 14 days of age. Birds fed diets severely deficient in aromatic amino acids (AAA), lysine or valine were found in most trials to have reduced serum concentrations of either 3,5,3'-triiodothyronine (T3) or 3,5,3',5'-tetraiodothyronine (T4). Approximately one-half of the samples assayed did not show detectable levels of 3,3',5'-triiodothyronine (reverse T3). The reduction in serum thyroid hormone levels was not observed until chick growth was markedly affected and was not specific for AAA deficiency. Phenylalanine alone could not efficiently supply tyrosine when dietary AAA were suboptimal as evidenced by significantly greater weight gains in chicks fed 50:50 or 55:45 (mole:mole) mixtures of phenylalanine and tyrosine as compared with birds fed the same total amount (moles) of AAA supplied solely by phenylalanine. However, at or above requirement levels, phenylalanine could completely meet the chick's demand for tyrosine. Serum tyrosine concentrations generally reflected the dietary levels of AAA.

Animals↗
PubMed1980

Methionine-cystine interrelationships in chicks and rats fed diets containing suboptimal levels of methionine.

Studies were continued with both chicks and rats on the previously reported (featherston and Rogler, 1978) growth depression observed when a crystalline amino acid diet adequate in all nonsulfur-containing amino acids and containing .2% DL-methionine and .2% L-cystine was supplemented with an additional .2% L-cystine. In the present investigation, an average growth depression of 37% was observed in chicks fed a diet containing .4% L-cystine and .2% DL-methionine as compared with chicks fed a diet containing .2% L-cystine and the same level of methionine. A comparable depression was noted when cystine was replaced by L-cysteine. In contrast, an additional .2% of another amino acid (L-tryptophan) did not depress growth. When the high and low cystine diets were meal-fed, results obtained were similar to those observed with ad libitum feeding, but the magnitude of the difference was reduced. Foot-pad lesions, similar to those described in turkey poults fed methionine-deficient diets, were observed in two experiments. Factorial analysis of plasma amino acids indicated that the total of all amino acids analyzed was significantly (P < .05) higher in chicks fed the lower cystine or cysteine diets. Plasma methionine was slightly lower (P < .10) but plasma cystine was significantly (P < .05) higher in chicks fed the cystine or cysteine supplemented diets. A study with .2 and .4% L-cystine and 200, 600, and 2000 mg/kg of choline (factorial design) demonstrated a significant (P < .05) depression in weight gain due to the added L-cystine, no significant (P < .05) differences due to choline, and the absence of a cystine-choline interaction. No detrimental effects were observed when weanling rats were fed a crystalline amino acid diet containing .1% DL-methionine and .2% L-cystine supplemented with additional L-cystine.

Animal Nutritional Physiological Phenomena↗
PubMed1980

Influence of dietary cystine on intestinal absorption and tissue distribution of methionine in the chick.

Studies were conducted on intestinal absorption and tissue distribution of methionine by chicks fed a crystalline amino acid diet containing .2% DL-methionine and .2 or .4% L-cystine or L-cysteine. Chicks fed the higher level of cystine or cysteine had previously been shown to exhibit depressed growth as opposed to chicks fed the lower level of these amino acids. In two experiments, 35S radioactivity of whole plasma and the protein and supernatant fractions were compared among chicks fed the different treatments at 30 or 60 min after oral intubation of L-[35S]-methionine into the crops. When the data were analyzed factorially, a significant level effect was noted for whole plasma and the protein and supernatant fractions, all of which were higher for chicks fed .2% L-cystine than those fed .4% L-cystine. Results with chicks fed the two levels of L-cysteine generally agreed with those of chicks fed L-cystine, although the differences were not as great. The labeled methionine was also added to diets containing .2 or .4% L-cystine of meal-fed chicks. Higher levels of radioactivity were observed in the liver but not in muscle or plasma of chicks fed the lower level of cystine at 7 hr after oral consumption of the isotope. No significant differences in liver, muscle, or plasma radioactivity were noted in a fourth experiment between chicks fed .2 or .4% L-cystine at 24 hr after intraperitoneal injection of L-[35S]-methionine. In vitro studies showed no differences in methionine accumulation by isolated intestinal segments incubated with three levels of cystine.

Animals↗
PubMed1979

Effect of sexual experience, location, malnutrition, and repeated sampling on concentrations of testosterone in blood plasma of Gallus domesticus roosters.

Five studies were conducted with mature White Leghorn roosters to study variables associated with concentrations of testosterone in blood sampled from a wing vein. Testosterone in blood plasma was unchanged 15, 30, or 45 min after collection of semen artificially whether or not roosters were trained for collection of semen. Likewise, cohabitation with hens for 7 to 8 hr was without effect. However, trained roosters had higher (P less than .05) plasma testosterone concentrations after 7 to 8 hr in a new location than untrained roosters. Furthermore, both groups in the new location had higher testosterone concentrations than the controls not translocated. Plasma testosterone was decreased (P less than .01) about 50% within 2 weeks by feeding a diet low in crude protein (2%) which decreased feed intake 33% and caused weight loss; those fed 12% crude proteins were unchanged. Variations in concentrations of testosterone among sequential samples of blood collected at 45 min intervals for 3 hr indicated random pulsatile releases of testosterone as reported for mammals. Sequential sampling at 15 min intervals for 1 to 2 hr revealed that the testosterone increases (up to 10 ng/ml) lasted for about 1 hr and that the returns to basal concentrations required about 1 to 1.5 hr. The interval between pulsatile releases may be as long as 3 hr in some roosters. These results indicate that roosters have spontaneous and pulsatile releases of testosterone as expected, because roosters release luteinizing hormone episodically during both light and dark cycles of the day.

Animals↗
PubMed1978

Methionine-cystine interrelations in chicks fed diets containing suboptimal levels of methionine.

Studies were conducted with chicks on the interrelationship between cystine and methionine in either crystalline amino acid or wheat-peanut meal diets containing suboptimal levels of these two amino acids. The crystalline amino acid basal diet contained 0.2% DL-menthionine and 0.2% L-cystine whereas the wheat-peanut meal diet contained 0.2% methionine and 0.26% cystine. Marked improvements in weight gain and feed efficiency were observed when these diets were supplemented with 0.2 to 0.6% DL-methionine. When similar levels of L-cystine were added to the basal diets containing 0.2% methionine, chick growth was depressed. When the diets contained 0.4% methionine, the growth depressing effect of cystine was not observed. These results point to the existence of an antagonism of cystine on methionine utilization when the dietary level of methionine is suboptimal.

Amino Acids, Sulfur↗
PubMed1978

Effects of environmental temperature on the iodine requirements of young chickens.

Growth rate of chicks maintained at 32 C was reduced as compared with chicks maintained at 21 C. Environmental temperature did not influence the iodine requirement for growth which appeared to be met with a level of approximately 75 ppb in both environments. Thyroid enlargement was observed in both environments for chicks fed low levels of iodine, but the magnitude of the enlargement was much greater at 21 C than at 32 C. A level of 75 ppb iodine was adequate for normal thyroid size at 32 C, but was inadequate to prevent thyroid enlargement at 21 C.

Animals↗
PubMed1978

Investigations of leg abnormalities in chicks consuming high tannin sorghum grain diets.

Studies were conducted into the etiology of leg abnormalities noted in chicks fed high tannin sorghum grain diets. These anomalies were characterized by a bowing of the legs with a swelling of the hock joints. The incidence of these leg problems was found to be markedly higher when the amino acids in the diet provided by soybean meal were replaced by crystalline amino acids. Supplemental vitamins and minerals had no alleviating effect on the leg problem. Bone mineralization was apparently not influenced by tannins as demonstrated by similar bone ash values for chicks fed high or low tannin sorghums. A possible alteration caused by tannin in the organic matrix of bone is discussed. High tannin sorghum depressed chick growth and feed conversion when compared with low tannin sorghum in both sorghum-soybean meal and sorghum-amino acid rations. This growth depression was overcome by supplementing the high tannin sorghum-soybean meal diet with .15% DL-methionine, but no growth response was observed from a similar supplementation of a high tannin sorghum-amino acid diet.

Amino Acids↗