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PubMed1992

Relationships among smoking status, body composition, energy intake, and physical activity in adult males: a longitudinal analysis.

This study evaluates the longitudinal relationships among smoking and adiposity, dietary intake, and physical activity in a group of adult males. Subjects were 101 nonsmokers and 19 regular cigarette smokers. Adiposity, dietary intake, and physical activity were assessed annually for three consecutive years. Results indicated that nonsmokers had larger tricep skinfold measurements than smokers over the 3-year period. However, dietary intake and physical activity did not differ between groups. Due to the absence of differences on these two variables for the smoking and nonsmoking groups, it was concluded that the lower adiposity in smokers was largely metabolically determined, which may make difficult the treatment of postcessation weight gain.

Adult↗
PubMed1982

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. II. Gait characteristics analyzed from 16-mm motion picture photography.

Three groups of 96 crossbred gilts were weaned at 4 to 5 wk of age (average initial weight, 7.2 kg) and assigned to four dietary treatments in a 2 X 2 factorial arrangement of treatments (ad libitum vs 75% ad libitum and 100 vs 150% of NRC daily Ca and P). The effects of dietary treatments on the gait characteristics of gilts were analyzed by 16-mm motion picture photography. At approximately 50 and 100 kg body weight (periods 1 and 2, respectively), pigs were photographed walking on a treadmill, and gait characteristics were measured from the motion picture film. Ad libitum-fed gilts were longer, taller, wider and deeper when compared with restricted-fed gilts on an equal age basis, but not when compared on an equal weight basis. Other side view and rear view measurements were inconsistently affected by energy level (ad libitum vs restricted) at the two time periods, and all measurements were unaffected by Ca and P level. Analysis of the side and rear view characteristics over time generally revealed undesirable changes (P less than .01) from 59 to 100 kg. Both left and right hock-joint deviation increased (P less than .01) from period 1 to period 2, when expressed on an equal weight basis, suggesting the development of joint weakness. The hind pastern angle and the angle at the hock-joint also increased with time (P less than .01), suggesting development of post-leggedness as pigs increased in age and weight. Correlation coefficients among the various photographic characteristics and structural soundness scores were generally very low. Long-term effects of the dietary treatments on structural development are under study.

Animals↗
PubMed2001

Limits to sustained energy intake. II. Inter-relationships between resting metabolic rate, life-history traits and morphology in Mus musculus.

Links between resting metabolic rate (RMR) and reproductive output have been previously sought at both inter- and intraspecific levels, but have only been found in some interspecific studies. We aimed to examine correlations between RMR measured both prior to breeding and at peak lactation with litter size and litter mass in Mus musculus. By manipulating the litter size of some females at birth, we aimed to establish the direction of causality in any correlation between litter size and RMR. Correlations between maternal morphology and RMR, litter size and litter mass were also examined. Neither pre-breeding RMR nor mass-independent pre-breeding RMR was correlated with litter size or litter mass. RMR at peak lactation, however, was positively correlated with litter size and negatively correlated with mean pup mass. After correcting for the effects of body mass, residual peak lactation RMR was not correlated with litter size or litter mass. Body size was the major morphological variable influencing litter mass, offspring mass and asymptotic food intake. Mammary tissue mass was correlated with litter size when only the data for mice raising unmanipulated litters were used. RMR at peak lactation was significantly related to the principal component of morphology dominated by carcass mass. This study confirms the findings of previous intraspecific and some interspecific studies that found no correlation between RMR and reproductive output after the effects of body mass had been removed.

Animals↗
PubMed2003

Limits to sustained energy intake. VIII. Resting metabolic rate and organ morphology of laboratory mice lactating at thermoneutrality.

We have previously shown that the food intake and milk production of MF1 laboratory mice lactating at 30 degrees C, 21 degrees C and 8 degrees C increase as temperature declines. These data suggest that mice are not limited peripherally by the capacity of the mammary glands to produce milk but are limited by the capacity of the animal to dissipate body heat generated as a by-product of food processing and milk production. Here, we measure resting metabolic rate (RMR; prior to breeding and at peak lactation) and organ morphology (at peak lactation) in MF1 mice exposed to 30 degrees C (thermoneutrality) and compare these traits with the same parameters measured previously in mice at 21 degrees C and 8 degrees C. The masses of visceral organs primarily responsible for energy flux (heart, lungs, stomach, small intestine, large intestine, liver, pancreas, spleen and kidneys) increased as temperature declined. The masses of all these organs differed between mice exposed to 8 degrees C and 21 degrees C, whereas only the masses of heart, liver and kidneys differed between mice at 21 degrees C and 30 degrees C. The increases in organ masses were paralleled by increases in RMR at peak lactation above the levels measured prior to breeding, with mice at 8 degrees C and 21 degrees C having significantly higher increases in RMR than mice at 30 degrees C (29.6 kJ day(-1), 25.5 kJ day(-1) and 8.1 kJ day(-1), respectively). The observed changes in visceral organs and RMR are consistent with both the heat dissipation and peripheral limit hypotheses. However, mice exposed to 8 degrees C had substantially larger mammary glands than mice at 21 degrees C or 30 degrees C (2.450 g, 1.115 g and 0.956 g dry mass, respectively), which argues against the peripheral limitation hypothesis and is consistent with the heat dissipation limit hypothesis. In addition, cold exposure resulted in greater masses of brown adipose tissue, white adipose tissue, pelage and tail. We discuss these changes in the context of the potential thermoregulatory benefits from use of the heat generated as a by-product of milk synthesis.

Analysis of Variance↗
PubMed1986

Combined effects of exercise and restriction of energy intake on moderately obese women.

The current study was designed to assess the contribution of dietary-induced weight reduction on improvements in functional capacity in moderate obesity. Twelve females (means age = 29 yr, means fat percentage = 37%) served as subjects for the study. Subjects trained on a cycle ergometer 30 min.day-1, six day.wk-1 for three or six weeks at 75 to 85 per cent of maximum heart rate (HR max). Improvements in maximal oxygen uptake (delta VO2 max I.min-1) and functional capacity (delta VO2 max ml.kg-1 min-1) were compared in an attempt to separate out training and dietary effects respectively. Measurements were also taken on both the cycle ergometer and treadmill to test for any specificity of training effects. Changes in body composition were assessed by densitometry. Following three weeks of training, there was an average increase in VO2 max ml.kg-1 min-1 on the cycle ergometer and the treadmill of 14 and 19 per cent respectively. By six weeks, this had increased to 18 and 26 per cent respectively. The contribution of weight reduction to the improvements in functional capacity was calculated to range from 20 to 33 per cent. Thus, both energy restriction and exercise training appear to be effective means of improving functional capacity in moderately obese women.

Adult↗
PubMed1983

Restricted energy intake and elevated calcium and phosphorus intake for gilts during growth. III. Characterization of feet and limbs and soundness scores of sows during three parities.

Gilts that had previously been fed ad libitum or 75% ad libitum intake and 100 or 150% National Research Council recommended daily Ca and P from weaning to 100 kg were used in a reproductive study in which a 14% protein diet was fed. Foot and leg measurements, subjective toe scores and structural soundness scores were taken at each of three parities, 21 d postweaning. Sows previously ad libitum-fed generally had larger front toes than limit-fed sows; whereas, hind toes were larger for sows previously fed 150% Ca and P levels than sows fed 100% Ca and P. Sows previously fed the ad libitum-150% Ca and P diet had the largest toes. Front inside toes were larger than hind inside toes, but the reverse was observed for front and hind outside toes, with the magnitude of the difference between the inside and outside toes greater for the hind foot. Toe size increased over parities with the greatest increase from parity 2 to 3. Incidence and severity of toe pad and horn scores were generally unaffected by previously fed energy and Ca and P levels and were not correlated to toe size. Hind feet exhibited a larger number of lesions than front feet and outside toes exhibited a larger number of lesions than inside toes, with the hind outside toe exhibiting the greatest number of lesions. In general, incidence and severity of toe lesions decreased or were unchanged from parity 1 to 3. Structural soundness scores were unaffected by previously fed energy or Ca and P levels, but were quadratically affected by parity, with a small increase (poorer) from parity 1 to 2 and a large improvement from parity 2 to 3. Soundness scores were not related to any of the feet or leg measurements and characteristics. Restricting growth rate and feeding elevated Ca and P levels during growth had no effect on incidence and severity of lesions on the toes and overall structural soundness of sows kept for three parities.

Animals↗
PubMed1976

Decreased dietary protein or energy intake and plasma growth hormone levels of the pregnant pig, its fetuses and developing progeny.

The effects of low protein diets on plasma growth hormone were studied in pregnant pigs, fetuses and the developing progeny. Pregnant pigs were fed 18%, 3% or 0.5% protein diet throughout the gestation period. At 10, 13 and 15 week of gestation, fetuses were removed from the uterus after the dam had been bled to death. Plasma samples were used for growth hormone determinations. In a second experiment, 2-day old pigs from another set of pregnant pigs fed the diet containing 18%, 3% or 0.5% protein during gestation were cross-fostered to control nursing dams and weaned at 4 weeks of age to a standard diet. Plasma obtained at regular intervals was used for growth hormone determination. Plasma growth hormone was significantly higher in dams fed 0.5% protein after week 13 of gestation. High growth hormone (ten times the dam GH level) was observed in all fetuses irrespective of maternal dietary manipulation. Offspring of severely protein deprived pits (0.5% protein) had significantly elevated growth hormone levels up to 12 weeks of age in spite of cross fostering to a control dam after birth. The data suggest that there is little or no effect of maternal protein restriction on fetal growth hormone levels but the persistent high growth hormone levels in the progeny of severely malnourished pigs indicate a possible impairment of the production, release or catabolism of growth hormone and/or its releasing factor.

Animals↗
PubMed1990

Long-term exercise training with constant energy intake. 3: Effects on plasma lipoprotein levels.

The composition and concentration of plasma lipoproteins were studied in five young men (mean BMI = 27.5 +/- 2.9 (s.d.] before, during (after 25 and 50 days of training), and after the completion of a 100 day exercise training program that induced daily 4.2 MJ calorie deficit. Along with reductions in body weight (from 86.7 +/- 20.0 to 78.7 +/- 17.1 kg, P less than 0.01) and in fat mass (from 17.0 +/- 9.7 to 10.4 +/- 7.4 kg, P less than 0.01), the exercise training program induced numerous changes in plasma lipoprotein levels. Plasma total cholesterol level fell significantly after 25 days of training (P less than 0.05) and remained significantly reduced at the end of the training experiment (P less than 0.05). This reduction in total plasma cholesterol was accompanied by reductions in plasma apoprotein (apo) B, LDL-cholesterol and LDL-apo B levels (P less than 0.05). There were trends for reductions in plasma triglyceride and VLDL components that were significant only for VLDL-triglycerides (P less than 0.05). Plasma HDL-cholesterol levels increased significantly only at the end of the training program (P less than 0.01). This increase in plasma HDL-cholesterol was not accompanied by an increase in plasma apo A-I levels suggesting that exercise training produced an increase in HDL cholesterol content rather than an increase in HDL particle number. Ratios of HDL-cholesterol/cholesterol (P less than 0.01) and apo A-I/apo B (P less than 0.05) were significantly increased by exercise training, suggesting a decreased risk of cardiovascular disease. These results indicate that a reduction in fat mass solely induced by aerobic exercise training has substantial beneficial effects on plasma lipoprotein levels.

Adult↗
PubMed1995

Effect of dietary energy intake and exogenous porcine growth hormone administration on circulating porcine growth hormone concentration and response to human growth hormone-releasing factor administration in growing swine.

In a 2 x 2 treatment array (n = 4 pigs/treatment), the effects of feed intake (ad libitum vs. restricted to 60% ad libitum) and the daily administration of excipient buffer or porcine pituitary-derived growth hormone (GH) at a dose of 100 micrograms/kg body weight per day on serum GH profile and human growth hormone-releasing factor (hGRF) response were examined in barrows weighing 55 kg. Feed intake treatment was implemented from 25 to 55 kg live weight. Buffer or GH treatment was implemented for 10 d before sampling. After GH treatment, the integrated serum GH concentration area was 25% greater in barrows fed restrictively. Data are consistent with the suggestion that GH dose to improve the efficiency of lean tissue deposition be adjusted according to feeding regimen. The serum GH response to hGRF was also altered by level of feed intake. The ad libitum feeding of buffer-treated animals resulted in a monophasic serum GH response to hGRF, whereas barrows fed restrictively had a biphasic response to hGRF. Together, these data suggest that feed intake pattern alters GH secretion and as such could influence the practical implementation of somatotropin as a metabolism modifier in swine.

Animals↗