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PubMed1978

The effects of a collegiate wrestling season on body composition, cardiovascular fitness and muscular strength and endurance.

The purposes of this investigation were: (1) to study the body composition, cardiovascular fitness and muscular strength and endurance of collegiate wrestlers during the course of a season; (2) to determine if selected regression equations used to predict minimal wrestling weight were accurate; (3) to determine if the wrestlers who participated in the study had an accurate perception of their ideal minimal wrestling weights. Body composition (body densitometry), aerobic power (Vo2 max), and muscular strength and endurance (isokinetic) were measured during pre, peak, and post-seasons. The fact that very few significant changes occurred in these measurements during the course of the study appears to be the result of year-round training on the part of the athletes studied. Their peak-season percent body fat (8.36%) was very similar to that reported in other studies involving mature wrestlers. Rapid weight loss through dehydration appeared to be the preferred method of weight reduction among these athletes.

Adult↗

PubMed1999

Body composition in Prader-Willi syndrome: assessment and effects of growth hormone administration.

Children and adults with Prader-Willi syndrome are usually overweight, if not obese. Nevertheless, it is now thought that the body composition exhibited by such individuals is markedly dissimilar to that found in simple obesity. In fact, the body composition typical of Prader-Willi syndrome is actually more characteristic of that found in individuals with growth hormone (GH) deficiency, namely an increased level of adiposity in the limbs in comparison with the trunk and an overall reduction in fat-free mass. This variation in body composition may impact upon the assumptions inherent in many techniques used to measure body size and body composition, such as the use of body mass index and skinfolds. Therefore, it is important that the potential error in body composition assessment is understood by professionals evaluating patients with Prader-Willi syndrome. Accurate assessment of body composition is critical in Prader-Willi syndrome, as a number of recent studies have revealed extremely similar findings relating to the effect of exogenous GH on the body composition of patients with this syndrome. Other notable findings of these studies include significant increases in muscle strength and exercise capacity, which probably result from the changes in body composition. The routine use of exogenous GH to treat this extremely debilitating syndrome should now be considered.

Body Composition↗

PubMed1996

Relative influence of age and menopause on total and regional body composition changes in postmenopausal women.

OBJECTIVE: We measured total and regional body composition to evaluate the differences in body composition associated with menopause and to determine whether the changes in fat distribution were more related to age or to menopause. STUDY DESIGN: Two hundred five healthy white women who had never received estrogen replacement therapy were studied according to menopausal status and age. Bone mass and body composition were measured by dual x-ray absorptiometry. The proportions of android and gynoid fat were calculated in all women and differences were sought by statistical analysis. RESULTS: Compared with premenopausal women, postmenopausal women were characterized by a significant increase in the proportion of android fat and the ratio trunk fat/leg fat, whereas the absolute amount of body fat mass did not significantly change. The different variables of android fat distribution tended to correlate better with years since menopause than with age. In multiple linear regression, years since menopause was a predictor of body fat mass and fat trunk, whereas age was not a predictor of any of the fat distribution variables. CONCLUSIONS: This study underlines the early changes in body fat distribution with a shift of body fat toward a more central location in postmenopausal women. This change in fat distribution appears to be more related to menopause than to age and might, together with other factors, contribute to explain the increased cardiovascular risk reported in postmenopausal women.

Aged↗

PubMed2004

Effects of energy intake and body weight on physical and chemical body composition in growing entire male pigs.

Two experiments were conducted to determine independent effects of BW and DE intake on body composition and the partitioning of retained body energy between lipid and protein in pigs with high lean tissue growth potentials and when energy intake limited whole-body protein deposition. In a preliminary N-balance experiment involving 20 entire male pigs at either 30 or 100 kg BW, it was established that whole-body protein deposition increased linearly (P < 0.05) with DE intake at both BW. These results indicate that DE intake controlled whole-body protein deposition and that these pigs did not achieve their maximum whole-body protein deposition when fed semi-ad libitum. In the main serial slaughter experiment, 56 pigs, with a BW of 15 kg, were assigned to one of four DE intake schemes and slaughtered at 40, 65, 90, or 115 kg BW. Within DE intake schemes, DE intake was increased linearly (P < 0.05) with BW, allowing for an assessment of effects of DE intake and slaughter BW on chemical and physical body composition (carcass, viscera, blood). Between 15 and 90 kg BW, average DE intake of 16.1, 20.9, 25.2, and 28.8 MJ/d supported average BW gains of 502, 731, 899, and 951 g/d, respectively. The proportion of whole-body protein present in the carcass increased with BW and decreased with DE intake (P < 0.05), whereas the distribution of whole-body lipid between carcass and viscera was not influenced by BW and DE intake. A mathematical relationship was developed to determine the relationship between DE intake at slaughter (MJ/d) and chemical body composition in these pigs: whole-body lipid-to-protein ratio = 1.236 - 0.056 x (DE intake) + 0.0013 x (DE intake)2, r2 = 0.71. The data suggests that absolute DE intake alone was an adequate predictor of chemical body composition in this population of entire male pigs over the BW and DE intake ranges that were evaluated, simplifying the characterization of this aspect of nutrition partitioning for growth in different pig populations.

Animal Nutritional Physiological Phenomena↗

PubMed2006

Body composition during GH replacement in adults - methodological variations with respect to gender.

OBJECTIVE: Men with growth hormone deficiency (GHD) may be more sensitive to GH treatment than women in terms of changes in body composition. We have studied whether age, body-mass index (BMI) and the different types of methodology used to assess body composition may explain these differences. DESIGN: Forty-four men and forty-four women with GHD, closely matched for age and BMI, were studied before and after 6 months of GH replacement. The dose of GH was individually adjusted. Body composition was assessed by measurements of potassium-40, total body nitrogen (TBN), tritiated water dilution, dual-energy X-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). Four- and five-compartment models for body composition were also calculated. RESULTS: The total daily dose of GH was similar in men and women at 6 months. Serum insulin-like growth factor-I (IGF-I) was higher in men than women at baseline and after 6 months of treatment (P = 0.01, paired t-test). The increment was, however, similar. In women, GH treatment reduced body weight and increased TBN. In both men and women, total body water and body cell mass increased, while total body fat (BF) mass decreased. At baseline, mean total BF varied considerably depending on the methodology used, with the highest value obtained from DXA. The changes in BF were, however, less dependent on the methodology, but DXA and BIA demonstrated the largest inconsistency between men and women. CONCLUSIONS: These results suggest that gender differences in body composition in response to GH treatment are small, if adjustments are made for baseline factors such as age, BMI and dose of GH. Different methods of body composition measurements produce different results, but changes in response to GH administration are less inconsistent.

Absorptiometry, Photon↗

PubMed1998

Bioelectrical impedance analysis (BIA) using bipolar foot electrodes in the assessment of body composition in Type 2 diabetes mellitus.

The use of bioelectrical impedance analysis (BIA) for determining human body composition is widely accepted as a safe, rapid, and reliable technique. Although this technique has been validated in normal and obese individuals, only limited studies have been done in special populations. The use of BIA for the measurement of body composition in Type 2 (non-insulin dependent) diabetic patients would be of particular interest for both clinical and investigative studies. The aim of this study was to evaluate the validity of a new bipedal BIA device for the measurement of body composition in a population of individuals with Type 2 diabetes mellitus. The body composition of 48 male and 48 female Type 2 subjects was measured by BIA and dual energy X-ray absorptiometry (DXA). The percentage body fat determined by BIA was significantly correlated with % body fat determined by DXA (r = 0.89, p < 0.0001). Agreement analysis showed that BIA consistently overestimated % fat in female diabetic subjects by approximately 5% and underestimated % fat in male diabetic subjects by approximately 10% of the predicted value obtained with DXA. These differences were statistically significant but probably of minor clinical relevance. We conclude that BIA measurement by TBF 105 is a useful and reliable technique for measuring body composition in subjects with Type 2 diabetes mellitus.

Adult↗

PubMed2003

Fan beam dual energy X-ray absorptiometry body composition measurements in piglets.

OBJECTIVES: A piglet model was used to validate and cross validate the fan-beam (FB) dual energy X-ray absorptiometry (DXA) software vKH6 and to determine the predictive values of physiologic parameters (weight, length, age and gender) on body composition. METHODS: Nineteen piglets (Group A: 600 to 21100 g) were used to validate the FB-DXA measurements of body composition based on chemical analysis of the carcass. An additional 22 piglets (Group B: 640 g to 17660 g) had FB-DXA measurements, and these values were compared to the predicted values generated from regression equations computed from group A piglets. Body composition for bone mass, lean mass and fat mass was based on ash weight, nitrogen and fat measured from three aliquots of homogenate from each carcass. Data from all piglets (n = 41) were used to determine the variations in body composition. Data analysis used regression, t test and analysis of variance. RESULTS: Duplicate DXA (total weight TW, bone mineral content BMC, bone area BA, bone mineral density BMD, lean mass LM and fat mass FM) measurements were highly correlated (r = 0.98 to 1.00, p < 0.001 for all comparisons) and were not significantly different. No significant differences were found in the residuals from predicted versus measured DXA values between the larger and the smaller (<1.6 kg) piglets from Group A. For Group B piglets, the DXA measured TW of 5666 +/- 5692 g (mean +/- SD), LM (5063 +/- 5048 g), FM (465 +/- 510 g), BMC (138 +/- 139 g), BA (486 +/- 365 cm(2)) and BMD (0.235 +/- 0.071 g/cm(2)) were highly significantly correlated with (r = 0.94 to 1.00, p < 0.001 for all comparisons) and were not significantly different from the predicted values. Data from all piglets (n = 41) showed that weight is the dominant predictor of whole body and regional body composition. Length, age or gender contributed to <2% of the variability of body composition. CONCLUSION: Body composition measurements using the FB DXA software vKH6 is highly reproducible. The software vKH6 is validated for use in a wide range of body weights and body composition, and cross-validated using a separate group of animals. Body weight is the dominant predictor of body composition in immature piglets.

Absorptiometry, Photon↗

PubMed1999

A new air displacement plethysmograph for the determination of Japanese body composition.

A new device based on the plethysmographic measurement of body volume, named the BOD POD Body Composition System, was developed for the purpose of estimating body composition. The performance, reliability, validity, and clinical application of this system were evaluated in Japanese subjects. The coefficient variation (CV:%) in same-day tests was 2.48, in three separate-day tests it was 2.27, and for independent operators it was 4.53, respectively. There was a clear correlation between the results from BOD POD and those from dual energy X-ray absorptiometry (DEXA) (r = 0.910, p < 0.01). Finally, the fat body composition of 4489 subjects (1499 men, 2990 women) was clinically measured by BOD POD. The findings indicate that the BOD POD is a highly reliable and valid method for determining body fat percentage. This new method has several advantages, e.g. it is quick, simple to operate and may accommodate wide populations.

Absorptiometry, Photon↗

PubMed1999

Testosterone, body composition and aging.

In addition to growth hormone (GH), sex hormones are important determinants of body composition. Aging is accompanied by a decrease in free testosterone levels and, as BMI as well as fat mass increase with age (with a redistribution of body fat), whereas muscle mass decreases, it is tempting to attribute a causal role to the decrease in androgen levels. In our study involving 372 males aged >20-85, age was found to be positively correlated with BMI and fat mass as measured by impedance, and negatively correlated with levels of free testosterone and free insulin-like growth factor-I. Multiple regression analysis revealed that BMI and age were independent determinants of testosterone levels. The latter decreased from 598+/-188 (SD) ng/dl in the young controls to 453+/-161 ng/dl in the elderly group, free testosterone decreasing from 15.35+/-4.10 to 8.38+/-2.51 ng/dl. Fat-free mass decreased by 18.9%. In a subgroup of 57 men aged 70-80 years, testosterone levels correlated negatively with percentage body fat (r=-0.57), abdominal fat (r=-0.56) and plasma insulin levels (r=-0.40). As GH levels and pulsatility also decrease with age and as, moreover, androgens amplify endogenous secretion of GH, it is not easy to determine the relative role of androgen deficiency in the age-associated changes in body composition. Moreover, increase in fat mass (obesity), as occurs in aging males, is in itself associated with low levels of free testosterone and GH which both normalize after weight reduction. The role of testosterone in the age-associated changes in body composition is, however, further suggested by the increase in lean body mass and in mid-arm circumference and the decrease in waist-to-hip ratio observed after testosterone treatment of elderly men with decreased testosterone levels. Also in healthy eugonadal men, testosterone treatment, at least in supraphysiological doses, causes an important increase in fat-free mass (+/-10%) and in muscle size. The changes in muscle volume are associated with an increase in muscle fibre diameter, suggesting that testosterone induces muscle cell hypertrophy. In conclusion, aging in males is accompanied by an important increase in fat mass and a decrease in lean body mass. Several indices of body composition are significantly correlated with plasma testosterone levels before and after correction for BMI and age. It is evident, however, that in addition to testosterone levels, the age-associated somatopause is also a determinant of the changes in body composition.

Adult↗

PubMed2001

Influence of female and male sex steroids on body composition in the rabbit model.

OBJECTIVE: To study the influence on body composition of estrogen replacement therapy (ERT) in female rabbits and of replacement therapy with testosterone (TRT) in male rabbits using dual-energy X-ray absorptiometry (DEXA). METHODS: Cholesterol-fed female and male rabbits receiving a weight-restricted diet (100 g/day) were used. Total lean tissue mass (LTM), total body fat tissue mass (FTM) and total tissue mass (TTM) were determined by DEXA at baseline, after which the animals were gonadectomized and treated with sex steroids. Soft body composition was then determined again after 30-31 weeks of treatment. RESULTS: Relative to controls, ERT with estradiol (E2) doses of 2 and 4 mg/day significantly increased LTM (p < 0.001), whereas E2 0.5 and 1 mg/day had a neutral effect on LTM. The change in fat mass, however, was not statistically significant between groups. In male rabbits, compared with castrated control rabbits, LTM decreased in testosterone-treated animals (by 7-12%; p < 0.001) but FTM decreased relatively more (by 66-79%; p < 0.0001). In both genders, body weight correlated with TTM as determined by DEXA (r = 0.89-0.91, p < 0.0001). CONCLUSION: In this in vivo model of growing rabbits, estrogen replacement significantly increased LTM in female animals, whereas testosterone replacement significantly decreased FTM in males, suggesting that soft body composition of both genders is significantly affected by replacement with sex steroids. Until comparable human data are available, it is speculated that similar changes in soft body composition may occur in humans treated with sex steroids.

Absorptiometry, Photon↗

PubMed2003

Growth and body composition in preterm infants with bronchopulmonary dysplasia.

OBJECTIVE: To compare growth and body composition in preterm infants with bronchopulmonary dysplasia (BPD) with normal healthy term infants during the first year of life. DESIGN: Twenty nine preterm infants with BPD (mean (SD) gestational age 27.1 (1.6) weeks; birth weight 852 (173) g) were followed prospectively. Anthropometry and body composition determined by total body electrical conductivity were measured and compared with those of healthy term infants at the same post-term age. RESULTS: In infants with BPD, the mean weight standard deviation scores (SD scores) 6 weeks after term were significantly lower (-1.44 and -2.68, boys and girls respectively) than in healthy term infants of the same age and did not improve during the first year. The mean length SD score was significantly lower in infants with BPD 6 weeks after term than in healthy term infants of the same age, and, although it improved significantly during the first year, the mean length SD score in girls with BPD was significantly below 0 12 months after term. In infants with BPD, the mean free fat mass (FFM) SD score and the mean total body fat (TBF) SD score at 6 weeks post-term age were significantly below 0. The mean FFM SD scores (-1.01 and -2.56, boys and girls respectively) and the mean TBF SD scores (-1.14 and -2.40, boys and girls respectively) 12 months after term were significantly lower than in healthy term infants of the same age. CONCLUSIONS: Preterm infants with BPD have impaired growth, with a deficit in TBF and FFM already 6 weeks after term; FFM and TBF remain low compared with healthy term infants during the first year of life. Nutritional intervention studies in infants with BPD are needed to evaluate if nutrition is the major determinant of growth and body composition or if this pattern of growth in preterm infants with BPD is the result of disturbed endocrine control.

Body Composition↗

PubMed1997

Determinants of body composition measured by dual-energy X-ray absorptiometry in Dutch children and adolescents.

Knowledge about body composition is important in metabolic and nutritional studies. In this cross-sectional study the body composition of 403 healthy white Dutch children and adolescents was evaluated by using dual-energy X-ray absorptiometry (DXA). Possible determinants of body composition were analyzed. In 85 subjects the results of bioelectrical impedance analysis (BIA) were compared with DXA. Fat mass, lean tissue mass, and bone mineral content were greater in older boys and girls. Percentage body fat was greater in older girls but not in boys and it was higher in girls than in boys at all ages. From the age of 14 y boys had higher lean tissue mass and bone mineral content than girls. Tanner stage had a significant relation with body composition in both sexes. Percentage body fat was lower in boys in stage 4 than in stage 3 and was higher in consecutive Tanner stages in girls. After adjustment for age, Tanner stage was significantly positively related to lean tissue mass and bone mineral content in boys and girls and to percentage body fat and fat mass in girls. The profession of the parents and the education of the father had a significant negative correlation with percentage body fat and fat mass in girls (P < 0.01). Physical activity was related to lean tissue mass (P = 0.001) but not to fat mass in boys after adjustment for age. A high correlation and a small difference was found between lean body mass by BIA and lean tissue mass by DXA. Body composition in healthy Dutch children and adolescents is related to age, sex, Tanner stage, socioeconomic status, and physical activity.

Absorptiometry, Photon↗

PubMed2002

Body composition estimates from NHANES III bioelectrical impedance data.

BACKGROUND: Body composition estimates for the US population are important in order to analyze trends in obesity, sarcopenia and other weight-related health conditions. National body composition estimates have not previously been available. OBJECTIVE: To use transformed bioelectrical impedance analysis (BIA) data in sex-specific, multicomponent model-derived prediction formulae, to estimate total body water (TBW), fat-free mass (FFM), total body fat (TBF), and percentage body fat (%BF) using a nationally representative sample of the US population. DESIGN: Anthropometric and BIA data were from the third National Health and Nutrition Examination Survey (NHANES III; 1988-1994). Sex-specific BIA prediction equations developed for this study were applied to the NHANES data, and mean values for TBW, FFM, TBF and %BF were estimated for selected age, sex and racial-ethnic groups. RESULTS: Among the non-Hispanic white, non-Hispanic black, and Mexican-American participants aged 12-80 y examined in NHANES III, 15 912 had data available for weight, stature and BIA resistance measures. Males had higher mean TBW and FFM than did females, regardless of age or racial-ethnic status. Mean TBW and FFM increased from the adolescent years to mid-adulthood and declined in older adult age groups. Females had higher mean TBF and %BF estimates than males at each age group. Mean TBF also increased with older age groups to approximately 60 y of age after which it decreased. CONCLUSIONS: These mean body composition estimates for TBW, FFM, TBF and %BF based upon NHANES III BIA data provide a descriptive reference for non-Hispanic whites, non-Hispanic blacks and Mexican Americans in the US population.

Adolescent↗

PubMed1995

Weight change and body composition in patients with Parkinson's disease.

OBJECTIVE: To compare reports of weight loss and actual measures of body composition to predict nutritional risk in patients with Parkinson's disease and matched control subjects. DESIGN: Patients and control subjects were asked to record prior changes in weight and activity. Body composition was then compared in both groups using percentage ideal body weight (IBW), body mass index (BMI), triceps skinfold (TSF) thickness, midarm muscle circumference, and percentage body fat (BF) as determined by bioelectrical impedance. SUBJECTS: Fifty-one free-living patients with Parkinson's disease and 49 matched control subjects were recruited from the neurology clinic and the surrounding area. MAIN OUTCOME MEASURES: We anticipated that reported weight loss would be greater and actual measures of body composition would show greater nutritional risk in the patients with Parkinson's disease. STATISTICAL ANALYSES PERFORMED: chi 2 Analysis was used to determine differences in the ratio of patients and control subjects who lost weight. Paired t tests were used to compare amount of weight change and measures of body composition. Correlations were performed among measures of weight change, body composition, and associated disease factors. RESULTS: Patients with Parkinson's disease were four times more likely to report weight loss greater than 10 lb than the matched control subjects (odds ratio > 4.2). Patients reported a mean (+/- standard deviation) weight loss of 7.2 +/- 2.9 lb and control subjects reported a mean weight gain of 2.1 +/- 1.6 lb (P < .01). Percentage IBW (P < .02), BMI (P < .009), TSF thickness (P < .005), and percentage BF (P < .022) were lower in patients. Significant correlations (P < .01) were found between reported weight change and percentage IBW, BMI, TSF, percentage BF, and stage of the disease. CONCLUSIONS/APPLICATION: Patients with Parkinson's disease appear to be at greater nutritional risk than a matched population. Simple screening and assessment tools can be used to detect nutritional risk.

Adult↗

PubMed2001

A longitudinal study of resting energy expenditure relative to body composition during puberty in African American and white children.

BACKGROUND: Body composition and resting energy expenditure (REE) have not been examined longitudinally during puberty. OBJECTIVE: The purpose of this longitudinal study was to examine the influence of pubertal maturation on REE relative to body composition in African American and white children. DESIGN: The study included 92 white and 64 African American children (mean age at baseline: 8.3 and 7.9 y, respectively) from Birmingham, AL. The children had 2-5 annual measurements of fat mass (FM), lean mass (LM), and REE. The Tanner stages of the children ranged from 1 to 5. Mixed-model repeated-measures analyses were used to test the change in REE relative to body composition with increasing Tanner stage among ethnic and sex groups. RESULTS: LM increased from Tanner stage 1 to subsequent stages. FM relative to LM decreased from Tanner stage 1 to stages 3, 4, and 5 but not from stage 1 to stage 2. The African American children had relatively higher limb LM and lower trunk LM than did the white children. REE declined with Tanner stage after adjustment for ethnicity, sex, FM, and LM. This decline was significant from Tanner stage 1 to stages 3, 4, and 5 but not to Tanner stage 2. After adjustment for age, Tanner stage, FM, and LM or LM distribution, REE was significantly higher in white than in African American children (by approximately 250 kJ/d). CONCLUSION: In a large sample of children at various Tanner stages, we found an ethnic difference in REE after adjustment for age, Tanner stage, FM, and LM that was not explained by the difference in LM distribution.

Basal Metabolism↗

PubMed1983

A comparison between muscle function and body composition in anorexia nervosa: the effect of refeeding.

Skeletal muscle function, body composition (total body nitrogen and total body potassium) and standard parameters of nutritional assessment were measured in six severely depleted patients with primary anorexia nervosa, both on admission and during oral refeeding. The function of the adductor pollicis muscle was assessed by electrical stimulation of the ulnar nerve. On admission muscle function was markedly abnormal in the patients with anorexia nervosa (n = 6) compared with normal subjects (n = 22), with a significant increase in the force of contraction at 10 Hz, with a mean +/- SEM of 48.0 +/- 3.7% and 28.8 +/- 1.2%, respectively (p less than 0.001). There was slowing of the maximal relaxation rate, 6.6 +/- 0.6% and 9.6 +/- 0.2%, respectively (p less than 0.001) and increased muscle fatigue 18.6 +/- 5.9% and 3.5 +/- 0.8%, respectively (p less than 0.01). Initially, the mean serum albumin was normal (4.0 +/- 0.1 g/dl), although there was evidence of severe depletion of somatic protein stores, with a low total body nitrogen and creatinine-height index. Within 4 wk of oral refeeding, maximal relaxation rate and muscle fatigability were restored to normal, and within 8 wk all parameters of muscle function were normal. During the study total body nitrogen increased by only 13% and was still 19.4% below the predicted normal total body nitrogen, whereas total body potassium increased by 32% and body fat by 46%. Normalization of muscle function may be related to restoration of muscle electrolytes rather than repletion of body nitrogen.

Adult↗

PubMed1993

In vivo measurement of changes in body composition: description of methods and their validation against 12-d continuous whole-body calorimetry.

The accuracy of a variety of in vivo body-composition techniques (densitometry, total body water, skinfold thicknesses, whole-body impedance and resistance, body mass index, and two three-compartment models) was assessed by comparison with fat balance. Three subjects were overfed and three underfed while confined to a 30-m3 whole-body calorimeter continuously for 12 d. Mean weight changes were +2.90 kg during overfeeding and -3.47 kg during underfeeding. The change in fat mass accounted for 37.1% during overfeeding and 59.3% during underfeeding. In comparison with energy and nitrogen balance, a three-compartment model yielded the least bias and greatest precision. The smallest change in fat mass that can be measured by such a method in an individual subject is 1.54 kg (2 SD). Of the prediction techniques considered, skinfold thicknesses or the body-mass-index formula appear to be more precise than estimates based on resistance or impedance.

Adolescent↗

PubMed1982

Cellular development of liver and skeletal muscles and body composition of pigs from gestationally starved sows.

Liver and skeletal muscle development and changes in body composition were studied in pigs from cross-bred sows subjected to starvation (allowed water and trace mineral salt) during the third trimester of gestation. Two groups of sows were taken off feed on days 93 (21-day) and 107 (7-day) of gestation respectively; a third group fed 1.82 kg of diet per day served as control. The pigs sacrificed at birth, were used to determine liver and skeletal muscle DNA, RNA and protein and body composition. There were no significant differences (P greater than .05) in body weight between the treated groups and the control. Liver weight was depressed in the progeny of 21-day and 7-day starvation groups (P less than .05). Liver cellular DNA was decreased (P less than .05) in the treated animals, RNA and protein content remained unchanged. The skeletal muscles studied responded differently to the treatment imposed; semitendinosus muscle weight, muscle DNA and RNA did not differ among treatments; whereas, gastrocnemius muscle weight, muscle DNA and RNA were significantly lower in the progeny of treated sows (P less than .05, P less than .01 and P less than .05 respectively). Muscle and liver protein content, RNA/DNA, and protein/DNA ratios were not affected by treatments. Body composition analysis showed no differences in per cent dry matter, lipid, ash and protein content. The results suggest that liver and gastrocnemius muscles were adversely affected by prenatal nutritional deficiency imposed while semitendinosus muscles remained unchanged. The differential response of skeletal muscles to prenatal nutritional deficiency indicated a need to study more than a single muscle in similar experiments designed to investigate muscle response. The lack of differences in body composition analysis showed that improved survival of newborn pigs previously reported can be achieved without changes in fetal chemical body composition.

Animals↗