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Biomedical subjects

A Arieli

Publications and source records attributed to A Arieli.

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

In situ evaluation of the ruminal and intestinal digestibility of heat-treated whole cottonseeds.

The effect of heating whole cottonseeds on the degradability of DM and CP in the rumen and the small intestine of lactating cows was determined in situ. Whole cottonseeds were heated for 1 or 2 h at 140, 160, or 180 degrees C prior to digestion. The degradation of DM and CP was determined in dacron bags suspended in the rumen for 3, 6, 9, 24, and 48 h. Bags incubated in the rumen for 24 h were introduced into the small intestine through a duodenal cannula and subsequently recovered in feces. The effective ruminal degradabilities of DM and of CP were evaluated, assuming a ruminal outflow rate of .08/h. Heating of whole cottonseeds decreased the degradability of DM and CP in the rumen with a corresponding increase in the amounts digested in the small intestine. The calculated temperature at which this effect was first observed was 130 degrees C. Following optimal heating amount of digestible CP reaching the small intestine more than doubled. The agreement between these findings and the results of previous in vivo experiments suggest that the dacron bag technique may reliably be used for determination of nutrient availability in the intestine.

Animals↗
PubMed1989

Prediction of duodenal nitrogen supply from degradation or organic and nitrogenous matter in situ.

The contribution of different feedstuffs to nitrogen reaching the duodenum was evaluated in situ. Dacron bags containing barley grain, corn grain, wheat silage, corn silage, alfalfa hay, rye grass, whole cottonseeds, or soybean meal were suspended in the rumens of three dairy cows fed roughage and concentrate diets. The effective degradability of the nitrogenous and organic matter of feedstuffs was calculated from their residues after incubation in the rumen for 3, 6, 9, 12, 24, 36, or 48 h. The duodenal nitrogen content at ruminal outflows of 2, 5, or 8%/h was calculated as the sum of undegradable dietary nitrogen and potential microbial nitrogen (assuming 32 g N/kg ruminally degradable organic matter). Comparison of the in situ estimates with previously reported in vivo measurements of duodenal nitrogen in cattle fed diets with similar ingredients to the tested feedstuffs yielded a linear relationship (r2 = .887). The dacron bag technique appears to hold promise for the prediction of nitrogen flow to the duodenum.

Animal Feed↗
PubMed1988

Effect of ratio of roughage concentrate on glucose-induced heat production in sheep rumen fluid in vitro.

The effect of ration on heat of glucose fermentation in sheep rumen fluid was investigated. Heat production was measured in a semiadiabatic calorimeter. In trial 1, the effect of glucose (.4 to 6.4 mg) on fermentative heat production was determined in rumen fluid from sheep fed 25 or 100% roughage diet. Heat of glucose fermentation decreased with increase in glucose dose in both diets. Maximal heat of glucose fermentation in both diets agreed with stoichiometric calculations. However, at 6.4 mg glucose, maximal heat was 18 kcal/mol in the 25% roughage diet and 14 kcal/mol in the 100% roughage diet. Purine N and maximal rate of heat production were not affected by diet type. In trial 2, the effect of glucose (1.6 and 6.4 mg) on fermentative heat production was determined in rumen fluid from sheep fed 25, 50, 75, and 100% roughage. In addition, fermentation pattern was measured in donors of the rumen fluid. Heat of glucose fermentation was positively correlated with organic matter digestibility and negatively correlated with rumen pH and acetate concentration. These observations indicate that in addition to the effect of roughage on the fermentation pattern, supplemental adaptation may occur, as indicated by the reduction in the heat of glucose fermentation.

Animals↗
PubMed1986

Thyroid status and noradrenaline-induced regulatory thermogenesis in heat acclimated rats.

Adjustments of the obligatory and regulatory thermogenesis upon heat acclimation (34 degrees C) and perchlorate treatment were observed in male rats. Resting oxygen consumption measured at neutral temperature was reduced, with respect to control, by 23, 27, and 34% in heat acclimated, perchlorate treated, and heat acclimated-perchlorate treated rats, respectively. Administration of 0.4 mg NA/kg increased oxygen consumption by 40, 30, 5 and 1% above resting level in control, heat acclimated, perchlorate treated, and heat acclimated-perchlorate treated rats, respectively. Whereas significant interaction was found between the effects of thyroid hormones and acclimation temperature on obligatory thermogenesis, the interaction of these factors on regulatory thermogenesis was not statistically significant. Still, hypothyroidism may be considered a thermoregulatory advantage during chronic heat exposure.

Acclimatization↗
PubMed1986

Effect of glucose on fermentation heat in sheep rumen fluid in vitro.

1. Heat production rate (H) of rumen fluid was measured in a direct calorimeter. Basal H of samples of 15 ml rumen fluid mixed with 45 ml buffer was 0.4 mW/ml rumen fluid. 2. Addition of glucose (0.4-6.4 mg/sample) was followed by a dose-dependent increase in H. Maximal H was 1.1 mW/ml and lasted up to 5 min, returning thereafter to the basal level. 3. Expression of fermentation heat (Hf; kJ/mol substrate added) against glucose dose indicated an asymptotic dose response. 4. Maximal Hf (at infinite dilution) agreed with stoichiometric calculations whereas minimal Hf suggested a partial fermentation of the substrate at a high-glucose dose in the rumen environment.

Animals↗
PubMed1985

Effect of food intake on exercise fatigue in trained and untrained subjects.

The effects of carbohydrate and fat intake on exercise-induced fatigue was investigated in 30 untrained--(VO2max of 40.6 +/- 2.7 ml X kg-1 X min-1) and 24 trained-subjects (VO2max of 52.3 +/- 2.7 ml X kg-1 X min-1) performing a 34 km march with a 25 kg backpack. Marching time was 8 1/2 h and 6 1/3 h in the untrained and trained-subjects respectively. The subjects were divided into 3 dietary groups. One group had free access to sugar cubes, the second group was offered almonds and the third one served as a control. Triglyceride levels decreased by 65 mg X dl-1 in untrained, and by 115 mg X dl-1 in trained subjects, while blood glucose remained at normal levels. In the untrained subjects, ingestion of almonds delayed the subjective sensation of exhaustion, while 50% of the controls and the sugar consuming subjects complained of exhaustion. The data suggest that ingestion of food containing fat delays exercise induced exhaustion or fatigue to a greater extent than does carbohydrate ingestion.

Adolescent↗
PubMed1985

Brown adipose tissue heat production in heat acclimated and perchlorate treated rats.

The noradrenaline-induced energy dissipation rate was measured with a direct microcalorimeter in brown adipose tissue taken from rats acclimated to 34 degrees C (HA), perchlorate treated (PC) and heat acclimated-perchlorate treated (HAPC). The response to 10(-7) M NA was reduced by 45%, 47% and 86% in HA, PC and HAPC groups, respectively, as compared to a control group kept at 24 degrees C. In the same groups, the response to 10(-6) M NA was reduced by 34%, 7% and 64%, respectively. The specific activity of the soluble alpha-glycerophosphate dehydrogenase in brown fat from HA rats was reduced by 50%, whereas it was not altered in the PC animals. It is concluded that the sensitivity to noradrenaline of the brown adipose tissue thermogenic mechanisms is decreased in hypothyroidism, and that the acclimation temperature and the thyroid status per se each have a different influence on brown adipose tissue function.

Acclimatization↗
PubMed1985

Triiodothyronine (T3)-induced thermogenesis: altered T3-efficiency in tissues from fed, starved, and refed hypothyroid rats.

A microcalorimetric study of perifused tissue samples obtained from hypothyroid thyroidectomized rats killed 15 h after a single injection of T3 was conducted in order to observe at the tissue level, and in a constant environment, the T3-dependent thermogenesis induced in fed, starved, and refed states. When 9 micrograms T3/100 g BW had been administered to fed animals, tissue heat production rate (E) increased in liver, soleus muscle, and myocardium. In kidney cortex an increase in E was observed only after 90 micrograms T3. A dose-response study was performed with liver samples, in which both oxygen consumption and heat production rates were measured. Liver and soleus muscle were then further investigated. T3-dependent thermogenesis could not be demonstrated in tissues obtained from rats which had been starved for 3 days before receiving 9 micrograms T3/100 g BW. After a small carbohydrate intake corresponding to about 60 kJ/rat (refed state; 1 kJ congruent to 0.4 kcal) given over a 3-h period preceding the injection of T3, T3-dependent thermogenesis was again present. It is concluded that differences in T3 dependent thermogenesis similar to those previously observed in animals under different nutritional states continue to exist in vitro, when tissues are no longer exposed to differing levels of humoral factors.

Animals↗
PubMed1985

Upper critical temperatures and forced ventilation effects for high-yielding dairy cows in a subtropical climate.

Upper limit of thermal stability and subsequent rise of thermoregulatory functions as affected by forced ventilation were examined. Rectal temperature, respiratory frequency, ear skin temperature, body weight, and milk yield were recorded biweekly July to March over 2 yr for 170 Israeli-Holstein cows (305-day milk yield 9000 kg/cow) at air temperatures 10 to 36 degrees C. Cows were in an open shelter. One side was force ventilated over 2.5 m along the stanchions (air velocity 1.5 to 3 m/s) from 0500 to 2200 h. Control side mean air velocity was .5 m/s. Within the 10 to 24 degrees C range, rectal temperature was not affected by air temperature or forced ventilation but increased by .02 degrees C/kg fat-corrected milk in animals producing above 24 kg/day. Between 26 and 36 degrees C rectal temperature increased with air temperature in both groups; rate of rise was halved by forced ventilation. In this range of air temperature, rectal temperature increased with rising milk yield, as in the lower air temperature range, in both high-producing and lower-producing cows in forced ventilation. Body weight or parity did not have significant effects. Mean ear skin temperature was higher for control animals, but its rate of increase with air temperature was similar in both groups. Forced ventilation reduced mean respiratory rate. An upper critical temperature is 25 to 26 degrees C and is independent of milk yield or acclimatizational state of cows exposed to the natural sequence of climate.

Animals↗
PubMed1985

Digestion and absorption of lipids and bile acids in sheep fed stearic acid, oleic acid, or tristearin.

Sheep were fed diets containing 7.5% added stearic acid, oleic acid, or tristearin for 21 days. In addition, 50 microCi/kg cerium-141 was included for the last 10 days on experimental diets as an unabsorbed reference substance. In the rumen dietary triglycerides were approximately 50% hydrolyzed, and hydrogenation resulted in saturation of the free fatty acid fraction. Some net synthesis of phospholipids, presumably microbial phospholipids, occurred in the rumen. In the intestine immediately distal to the pylorus, extensive secretion of bile acids, cholesterol, phospholipids, triglycerides, free fatty acids, and lipase occurred. This resulted in doubling of fatty acid fluxes through the duodenum. These endogenous secretions were reabsorbed rapidly however, with the major site of lipid and bile acid absorption in the region .6 to 4 m distal to the pylorus. Additional but less absorption occurred in the more distal segments of the small intestine. Overall absorption of stearic acid, oleic acid, and tristearin supplements was in the range 60 to 70%, and no differences were apparent between fats. Unsaturated fatty acids were over 90% absorbed as compared with 55 to 65% for saturated fatty acids. No significant effect of any of the supplements was observed on ruminal total volatile fatty acids, ratios of volatile fatty acids, or on overall cellulose or caloric digestion.

Abomasum↗
PubMed1985

Energy disappearance in hindgut of sheep.

Digestibility and disappearance of energy in the large intestine of sheep fed 75% concentrates was investigated with Cerium-141 as an unabsorbed reference substance. Cecal fermentation increased acetic acid and decreased propionic acid compared with ruminal fermentation. This situation was associated with cellulose disappearance in the lower gut and accounted for 26% of total cellulose disappearance from the entire alimentary tract. Energy disappearance in the hindgut accounted for 13% of energy disappearance in the gastrointestinal tract.

Acetates↗
PubMed1981

Multicouple group therapy of alcoholics.

A method of multicouple group therapy is described. Seven hospitalized alcoholics and five spouses participated in this group. Emphasis was put on intramarital conflicts. The contribution of the wife to the alcoholism of her husband as well as the intrapsychic conflict with her domineering needs is reviewed and discussed. The special contribution of multicouple therapy is investigated as to its influence of these conflicts. The principle of this technique is outlined and clinical illustrations are presented. A follow-up after 13 months showed that there was an improvement in four of the five familial atmospheres, a change of drinking habits in three of five alcoholics, and an amelioration in neurotic and psychosomatic symptoms in three of the five spouses.

Adult↗
PubMed1980

The thermoneutral temperature zone and seasonal acclimatisation in the hen.

1. Oxygen consumption, body temperature, respiratory frequency and respiratory water loss of White Leghorn x Rhode Island hens were measured for short periods at six air temperatures between 2 and 32 degrees C. The hens were kept between tests in an open shed. The experiments were carried out over 3 years. 2. The upper critical temperature (Tcu) was estimated by the air temperature at which: 1, respiratory frequency increased above 60 respirations/min and 2, body temperature increased by 0.3 degrees C above that at the lower critical temperature. These responses to the test temperatures were examined as a function of the acclimatisation temperature (Ta) represented by the mean daily temperature during experimental periods. 3. A seasonal change in Tcu was observed, which correlated with Ta(r = 0.836). The seasonal 10 degrees C change in the Ta brought about a 3 degrees C change in Tcu, compared with an 8.5 degrees C change in the lower critical temperature. 4. Thermoneutral temperature zone decreased with increasing Ta; the two critical temperatures tended to merge at a Ta of 32 degrees C. The latter probably represents an upper limit for acclimatisation to heat.

Animals↗
PubMed1979

Seasonal acclimatisation in the hen.

1. The oxygen consumption and body temperature of White Leghorn x Rhode Island Red laying hens, which were being kept in a semi-natural climate, were periodically measured for short periods at ambient temperatures between 2 and 32 degrees C in a suitable chamber. 2. A seasonal shift was observed in lower critical temperature (Tc) and thermoneutral oxygen consumption. The slope of the relationship between oxygen consumption and air temperature at less than Tc was not discernibly affected by season. 3. The seasonal shifts correlated best with mean daily outside temperature Ta) during the experimental periods; a seasonal decrease of 10 degrees C in Ta was associated with a decrease of 8.5 degrees C in Tc and a 12% increase in thermoneutral oxygen consumption. 4. The capacity to maintain body temperature stability at extremes of environmental temperature was improved by acclimatisation to heat.

Acclimatization↗