Relative Fat Content Research Articles

Aussage des Harnstoffverteilungsraumes zum Körperfettgehalt der Milchkuh

Abstract. Title of the paper: Utilization of urea space for estimation of body fat content in dairy cow The urea space 12 minutes after intravenous administration of a defined amount of urea (HVR12) is unsuitable for estimation of body fat content in dairy cows. There is no connection between the absolute body fat content and the absolute HVR12. Between the relative body fat content and the relative HVRI2 combined a low significant measure of accuracy is established. Bibliographical references about unsatisfactory results by use of this method particulary in lactating cows are confirmed.

Embryo and yolk compositional relationships in broiler hatching eggs during incubation

Developmental relationships between yolk, embryo body, and embryo liver compositions during incubation were determined in two trials. In Trial 1, embryo body moisture, fat, and CP contents and embryo liver moisture and fat contents were determined. In Trial 2, relative yolk weights, moisture, fat, and fatty acid contents, relative wet and dry embryo weights and moisture contents, and relative wet and dry liver weights and moisture contents were determined. In Trial 1, embryo moisture decreased sigmoidally between Days 6 and 21, whereas embryo fat increased between Days 12 and 21 of incubation; embryo CP displayed sequential fluctuations throughout incubation. However, an overall significant decrease in embryo CP occurred between Days 6 and 21. Liver fat content increased between Days 12 and 21, whereas liver moisture decreased through Day 18, with a subsequent increase by Day 21. In Trial 2, relative yolk weight and moisture content decreased, whereas percentage yolk lipid content increased between Days 6 and 15. Relative wet and dry embryo weights changed in a similar manner, with rapid increases between Days 12 and 18 of incubation. Embryo moisture and CP were negatively correlated to embryo fat content. Furthermore, relative embryo and liver DM were related to yolk palmitic acid concentration, whereas yolk oleic acid was correlated only with liver DM. In conclusion, embryos and their livers displayed differential accumulations of moisture and DM during incubation, and these differences exhibited distinctive associations with various yolk fatty acids.

Growth and Sexual Size Dimorphism in Northern Water Snakes (Nerodia sipedon)

Understanding the evolutionary basis for sexual size dimorphism (SSD) in a species first requires determining the extent to which observed SSD is a result of sex differences in growth or in size at maturity, as opposed to being a consequence of factors such as differential survival or catchability of the sexes. We used data from a nine-year study to assess how these factors contribute to female-biased SSD in Nerodia sipedon in eastern Ontario. Females grew substantially faster and larger than males, although both sexes approached their asymptotic size at the same rate. Smaller individuals of both sexes grew faster, and snakes grew faster in years with higher mean air temperatures during the activity season. Variation in growth rate was unrelated to relative fat content of individuals in the spring. We found no evidence that either the sex or size of individuals affected their probability of capture. However, comparisons of estimated ages of males and females, and a null growth-based analysis, both indicated that large, old males were overrepresented in capture samples, probably as a result of differential survival of males and females. The overrepresentation of large males caused us to slightly underestimate SSD caused by sex differences in growth. A comparison of sex-specific growth patterns in our population of N. sipedon with those in two other N. sipedon populations suggests that intraspecific variation in SSD in this species may be primarily a consequence of differences between populations in selection pressures on males.

Sexual dimorphism in physiological performance of whiptail lizards (genus Cnemidophorus).

Numerous studies have examined sexual dimorphism in the morphology and behavior of vertebrates; very few, however, have explicitly investigated the possibility of gender differences in physiological performance, despite the observations of such differences in humans. In this study, I investigated physiological sexual dimorphism in the lizard genus Cnemidophorus by measuring five whole-animal traits, all of which are likely to influence fitness in these species: burst speed, endurance, maximal exertion capacity, standard metabolic rate, and evaporative water loss rate. Because at least some of these traits are known to be strongly influenced by body size, I tested for dimorphism using both absolute and size-corrected trait values. An examination of six Cnemidophorus species and subspecies revealed a strong trend toward higher absolute trait values in males for all variables except endurance. Most of the dimorphism in standard metabolic rate and evaporative water loss rate could be explained by differences in body mass between males and females; for the locomotor traits, however, body size explained only a small fraction of the overall sexual dimorphism. The portion of trait differences not explained by body size was likely due to gender differences in physiology, such as differences in relative muscularity and fat content.

Disruption of the relationship between fat content and leptin levels with aging in humans.

Leptin released from adipose tissue is believed to participate in a negative feedback loop regulating appetite, and malfunction of this mechanism could lead to obesity. We measured plasma leptin and body composition (dual energy x-ray absorptiometry) in 70 healthy subjects, divided into 3 age groups (young, 25 +/- 1 yr; middle-aged, 53 +/- 1 yr; old, 70 +/- 1 yr), while on a 5-day weight-maintaining diet. Pairwise correlations were assessed using product-moment correlation, and regression analysis was used to evaluate relationships between leptin and other variables. Leptin concentrations and relative body fat content were correlated in young females (r = 0.71; P = 0.009) and in young males (r = 0.76; P = 0.007), but not in the combined middle-aged and elderly groups (r = 0.19; P = 0.36 and r = 0.19; P = 0.38 in females and males, respectively). Regression analysis showed a clear correlation between circulating leptin and relative fat mass in the young subjects (P = 0.0001), but not in the older subjects (P = 0.199). We conclude that body fat content in young subjects correlates with plasma leptin in both genders, whereas this relationship is disrupted in elderly subjects, thus possibly contributing to the obesity occurring with age.

The influence of replacing fish meal in the diet with fish oil on growth, feed utilization and body composition of Atlantic salmon ( Salmo salar) during the smoltification period

The effects of replacing fish meal with fish oil in diets fed to Atlantic salmon during the smoltification period were investigated in a 9-week trial. Reducing the dietary protein level from 57 to 47% and increasing the energy level from 21 to 24 MJ/kg diet had no significant effects on feed intake, growth or feed utilization. The use of a diet containing less than 20 MJ/kg digestible energy (DE) resulted in a significant decrease in percentage fat in the carcass, whereas fish fed diets containing greater amounts of DE showed an increase in carcass fat. In contrast, the relative fat content of the viscera decreased in all groups during the trial, indicating a preferential use of the lipid in this tissue for energy. These results show that the changes in body composition occurring during smoltification can be influenced through diet composition.

Influence of dietary fat level on feed intake, growth and fat deposition in the whitefish Coregonus lavaretus

Whitefish, Coregonus lavaretus, of initial mean weight 260–265 g were fed either a high-fat or a low-fat diet (dietary fat: 27.5% vs. 12.6%) to examine the influence of dietary fat level on feed intake, growth and patterns of fat deposition. The fish were held at 14.5 °C under a 24L:0D photoperiod, and were fed for 4 h each day. The experiment was run for 11 weeks during which feed intake (three times by X-radiography) and growth were monitored. Samples of fish were taken for body composition analysis at the start and end of the experiment. There were only small differences between dietary treatment groups in feed intake and final body weights, but the body composition of the fish was significantly influenced by the fat content of the diet. The whitefish fed the high-fat diet tended to have higher relative fat contents in the viscera [% fat as mean (SD): 29.6 (9.4)% vs. 22.1 (10.0)%] and carcass [% fat: 12.7 (1.9)% vs. 10.5 (1.3)%] than their counterparts fed the low-fat diet. This resulted in a higher whole-body fat concentration [% fat: 14.0 (1.9)% vs. 11.5 (1.5)%] amongst the fish fed the high-fat diet, and these fish had a higher energy gain than the whitefish fed the low-fat diet. The results confirm that it is possible to manipulate the chemical composition of whitefish by changing dietary composition. © Rapid Science Ltd. 1998

Seasonal variation in body composition and gut capacity of the prairie vole (Microtus ochrogaster)

Prairie voles (Microtus ochrogaster) were trapped during different seasons in order to examine simultaneous variation in body composition and gut capacity. Voles in reproductive condition were trapped in May, August, and November but not in February. Body masses of adult voles were lowest during February 1994. Adult males showed no seasonal variation in absolute lipid mass but did exhibit variation in relative fat content (percent body fat), with the highest values found in February 1994. Both absolute lipid mass and relative fat content of adult females varied with month of capture and were higher in February of both 1994 and 1995. Juvenile voles showed no variation in body composition between seasons and had fat levels similar to those of adult voles in the breeding months. Wet mass of the gastrointestinal tract varied with season of capture for both adult males and females, but no distinct pattern was evident. Mass of gut contents varied between trapping periods for adult males, but there were no seasonal differences in the gut contents of adult females or juveniles. The average mass of gut contents was higher than previously reported for field-caught prairie voles; this difference is likely due to the use of snap traps versus live traps.

Influence of Relative Fat Content Information on Responses to Three Foods

Thirty-six normal-weight participants each tasted and rated three cheeses, three yoghurts and three “kœrrtas” (a novel, tofu-based food) on several hedonic, intention and sensory dimensions. Each sample was labelled as either“Higher”(than normal fat content),“Normal”, or“Lower”(than normal fat content) while the actual fat content remained virtually constant. Cheese and yoghurt were chosen as consumers thought them to be high and low fat foods respectively in pre-testing. The presence of significant and predictable label effects on dimensions such as perceived healthiness and amount of fat demonstrated the efficacy of the manipulation. TheLowerlabelled foods were rated slightly less pleasant than theNormalbut there was no interaction with type of food. However, there was an interaction with food type for rated likelihood of buying: participants were more likely to buy theLowerlabelled yoghurt than theNormalorHigheryoghurts. Participant characteristics were important moderators of the effect of the dietary fat-related labels. Those participants who reported a greater perceived influence of general health concerns on food choice, for example, rated thehigherfat labelled foods as less pleasant and tended to be less likely to buy thehigherlabelled yoghurts and cheeses than those who reported a lower perceived influence.

Changes in supercooling with body size, sex, and season in the long‐lived milliped Polyzonium germanicum (Diplopoda, Polyzonidae)

The supercooling points (SCPs) of a field population of Polyzonium germanicum were measured at different stages in the life cycle. There was no post‐freezing survival under the experimental conditions used. The mean SCP was ‐26.2°C for eggs and increased to ‐18.2°C for juveniles of stadium III experiencing their first winter. From stadium V onwards, SCP varied considerably among individuals, ranging from ‐22.7 to ‐4.7°C. SCP was shown to increase significantly with body size in both sexes. Seasonal changes also occurred in males, SCP being lower in autumn‐winter than in spring‐summer. Measurements from a sample starved in the laboratory showed that the winter decrease could result from starvation affecting a proportion of males in the field. There was no relationship between the SCP and relative water content of individuals. After starvation in the laboratory, however, there was a relationship between the SCP and relative fat content of males. The results show that freezing is not a significant threat to the field population studied, with the possible exception of the largest overwintering females.

Effect of defensive behaviour by cattle on the feeding success and nutritional state of the tsetse fly, Glossina pallidipes (Diptera: Glossinidae)

AbstractTwo experiments were conducted at Galana Ranch, Kenya, which examined, under natural conditions, the relationships between the number of tsetse flies (Glossina pallidipes Austen) attracted to cattle, the rate at which the cattle made defensive movements, and the feeding success of the tsetse. The most frequent defensive movements were skin ripples and tail swishes, while leg kicks were of intermediate frequency, and head and ear movements were infrequent. In one experiment, the rate of skin ripples, but no other type of defensive movement, was significantly correlated with the number of tsetse attracted to the cattle. The proportion of tsetse that engorged was significantly (P < 0.004) correlated with the rate of leg kicks, more weakly with the rate of head movements (P < 0.07), and uncorrelated with the rates of other types of defensive movement. In the second experiment, the rates of skin ripples, tail swishes and leg kicks were significantly correlated with the number of tsetse attracted to the cattle. The proportion of tsetse that engorged was again significantly correlated to the rate of leg kicks (P < 0.03), more weakly to the rate of head movements (P < 0.04), and unrelated to the rates of other types of defensive movement. In neither experiment was there a significant relationship between the number of tsetse attracted to the cattle and the proportion that engorged, suggesting that any density-dependent feeding success was too weak to be detected. In experiment 1, the relative fat content of the male G. pallidipes that fed decreased as the rate of leg kicks increased, suggesting that when hosts are more active the sub-sample of tsetse that feed, out of those that approach, is both smaller and hungrier. There was no detectable effect of host defensive behaviour on the bloodmeal size of male G. pallidipes.

Very—low-density lipoprotein of uremic patients is a poor substrate for bovine lipoprotein lipase in vitro

Very—low-density lipoprotein (VLDL) from 10 hemodialysis patients and 10 healthy controls was studied with respect to the substrate characteristics for bovine milk lipoprotein lipase (LPL). Compared with the control subjects, the hemodialysis patients had significantly higher serum triglyceride and apolipoprotein B—associated apolipoprotein CIII concentrations (1.03 ± 0.31 v 1.98 ± 0.86 mmol/L and 0.004 ± 0.002 v 0.011 ± 0.005 g/L, respectively), lower serum high-density lipoprotein (HDL) cholesterol and apolipoprotein Al concentrations (1.33 ± 0.37 v 0.95 ± 0.31 mmol/L and 1.29 ± 0.25 v 1.09 ± 0.23 g/L, respectively), and lower postheparin plasma LPL activity (82 ± 24 v 35 ± 14 mU/mL). There were also significant increases in the relative fat content and diameter of VLDL particles from patients versus controls. VLDL was labeled with a fluorescent phospholipid analog, DHPE, and the rate of the lipolytic reaction with purified bovine milk LPL was estimated from the increase in fluorescence intensity at 490 nm. There was no significant difference between initial reaction velocities in the study groups, but VLDL particles from hemodialysis patients were lipolyzed to a significantly lesser extent than those from healthy controls (mean increase in fluorescence intensity after completion of the reaction, 95 ± 36 v 140 ± 43 arbitrary units). These results are in accordance with the accumulation of remnant particles reported to occur in uremia despite only a moderately increased serum triglyceride concentration.

Body size and condition, age, plumage quality, and foods of prenesting male cinnamon teal in relation to pair status

Male-biased sex ratios in waterfowl may contribute to sexual selection and permit females to be the deciding sex in mate selection. Male characteristics potentially influencing female choice include male age, size, plumage quality, and body condition (i.e., relative body mass, fat content, or protein content). By examining characteristics of prenesting male cinammon teal (Anas cyanoptera) relative to their pair status we evaluated the predictions that (i) paired males are older and physically superior to unpaired males and (ii) older and physically superior males pair in advance of other males. Diets of paired and unpaired males were similar, as were body size, ingesta-free body mass, fat, breast, and leg muscle protein contents, and testis, liver, and plumage masses. Likewise, pair status was not associated with male age. Body protein content and percentage of alternate plumage were generally greater in paired than unpaired males, but for some unpaired individuals these values were higher than the mean values for paired males. Thus, we found only limited evidence to support the above hypotheses. Our data suggest a possible link between winter nutrition and male participation in reproduction. That is, characteristics which enable males, during winter, to acquire nutrients for initiating and completing the prealternate molt in advance of other males also may be associated with ability to obtain a mate.

Assessment of energy reserves by damselflies engaged in aerial contests for mating territories

Abstract. Male Calopteryx maculata (Odonata) damselflies engage in prolonged, highly escalated aerial contests for mating territories. A previous study (Marden & Waage 1990, Anim. Behav., 39, 954-959) found that winners of contests had a higher fat content than losers in 88% of cases, whereas differences in physical variables related to size and flight ability were not related to the outcome of contests. Here that study is extended in order to determine whether contests proceed until one contestant reaches a lower physical limit in fat reserve, or alternatively, whether contestants are able to assess each other's fat reserves and thereby settle contests before physical limits are reached. The physical limitation hypothesis was not supported, as losers showed no reduction in variability of fat content relative to winners. The assessment hypothesis was supported by an increase in the accuracy of the 'fatter wins' rule with increasing contest duration. Winners were fatter in 17 of 25 (68%) short contests (duration <500 s), versus 20 of 21 (95%) long contests (>500 s), which suggests a gradual accumulation of information during contests. The assessment hypothesis was supported further by a negative relationship between contest duration and energetic asymmetry between contestants in long contests. Duration of long contests was also positively related to the total fat content of the two contestants, which suggests that the ability of contestants to perceive relative energetic status may vary depending on absolute levels of energy reserves. A model that assumes an asymptotic increase in flight performance with increasing fat content (i.e. Michaelis-Menten or 'saturation' kinetics) is proposed to explain the simultaneous effects of relative and absolute fat content on contest duration, and to examine possible mechanisms that damselflies use to assess each other's energy reserves.

Effect of Meal Macronutrient and Energy Content on Human Performance

The effects of planned meals, varying in carbohydrate (CHO), fat and caloric content, on psychomotor performance by male subjects with unrestricted access to commercially-available foods was investigated in two residential studies. In the first study, two groups of three subjects (n = 6) completed psychomotor tasks before and after consuming a lunch consisting of 431 or 844 kcal, with caloric differences produced through covert changes in either fat or CHO content. The effects of each of four lunch conditions (low-fat, high-fat, low-CHO, high-CHO) were determined for three consecutive days. In the second study, two groups of three subjects (n = 6) received breakfast, lunch and an afternoon snack and completed psychomotor tasks after breakfast and lunch. Cumulative caloric content of the three eating occasions was approximately 700, 1200 or 1700 kcal (low, medium or high), again with differences resulting from covert changes primarily in either fat or CHO content. The effects of each of six food conditions were determined for two consecutive days. While changes in some aspects of performance were altered after meals, the effects were not related to the CHO, fat or caloric content of the meal. When subjects have unrestricted access to commercially-available foods, neither calories nor the relative fat or CHO content of normal meals influence human psychomotor task performance.

Role of prolactin and the gonads in seasonal physiological changes in the collared lemming (Dicrostonyx groenlandicus)

On a seasonal basis, collared lemmings undergo a number of physiological and morphological changes. Short photoperiod exposure results in a molt to a white pelage, an increase in body weight, a reduction in relative body fat content, an increase in relative water content, and the development of a bifid claw. Treatment with the dopamine agonist, CB-154, resulted in a reduction in serum prolactin and the development of the white pelage in lemmings housed under 16L:8D, while treatment with the dopamine antagonist, sulpiride, prevented the winter molt in animals transferred to 8L:16D. Castration under 16L:8D resulted in an increase in body weight and an enlargement of the bifid claw. Castrated animals also molted more readily when treated with CB-154 and developed a relatively greater carcass water content. Treatment with CB-154 increased relative carcass fat content. These findings suggest that, in the collared lemming, seasonal changes in pelage parameters are regulated by prolactin, with gonadal hormones playing a modulating role. Body weight, water content, and bifid claw size appear to be influenced by gonadal hormones.

Changes in the structure and function of the epaxial muscle of rainbow trout ( Oncorhynchus mykiss) in relation to ration and age : III. Chemical composition

The chemical composition of white and red muscle has been studied in rainbow trout in relation to age and ration level (RL), together with the deposition and mobilization of fat from the three main adipose tissues (viscera, dorsal and abdominal wall). Protein in red and white muscle increased with age up to 1.4 years and remained practically constant from then on, irrespective of ration level. In all tissues studied, fat content increased with age until a final steady level was reached, dependent on ration level and tissue. In white muscle and viscera, however, this increase was preceded by a decrease in fat content (0.3–1.1 years). Subjecting fish to a new RL resulted in a change in the fat content to the same level as that in fish fed at this RL from the start. The total amount of fat was regulated in all tissues, except visceral adipose tissue, by altering the relative fat content rather than by increasing or decreasing the relative size of the tissue. Overall changes in dry matter content, from hatching to sexual maturation, correlated mainly with protein in white and with fat in red muscle. However, when young and older fish were studied separately it became apparent that a change in protein content was closely related to changes in dry matter in both muscle types early in life (fish < 1.1 years) and fat later on (> 1.1 years). The glycogen level varied in parallel in red and white muscle, except for the large increase in white versus red muscle after the glycogen depletion in connection with saltwater transfer. Subjecting fish to a new RL caused rapid changes in glycogen content in young specimens. Underfed fish produced markedly elevated levels of muscle glycogen. Season, sex or sexual maturation had no effect on the chemical composition of the muscle.

Factors affecting food efficiency and body composition of growing ruminants offered straw-based diets: supplementation with lipids with and without protein meal

ABSTRACTGrowing heifers (experiment 1) and wether lambs (experiments 2 and 3) were offered ammoniated cereal straw with or without a protein meal. The effects of supplementation with long-chain fatty acids (LCFA; as calcium salts of LCFA (CaLCFA) or fat prills) on nutrient utilization were studied.Intake of the basal diet (g/kg live weight) was unaffected by the protein meal, but was often reduced by supplementation with LCFA, especially fat prills. Live-weight gain was increased both by supplementation with protein meal and CaLCFA. Fat prills only increased live-weight gain in the presence of protein meal and depressed live-weight gain in the absence of protein meal. There were small differences between the two sources of LCFA in their apparent effects on rumen fermentation.Supplementation with protein meal increased relative protein content (P &lt; 0·05) and tended to increase water content (P &gt; 0·05) in the wethers in experiment 3 (corrected to equal empty-body weight at slaughter). Of the LCFA, only CaLCFA tended to increase relative body fat content (by proportionately 0·23; (P &gt; 0·05) but decreased relative protein and water content by 0·05 and 0·06 (P &lt; 0·05).Supplementation of straw-based diets with as little as 20 g CaLCFA per kg food dry matter improved live-weight gain and efficiency of nutrient utilization of ruminants, particularly when offered in combination with a protein meal. There appeared to be marked differences in the effects of CaLCFA and fat prills on food intake, productivity and to some extent body composition.

Proton MR chemical shift imaging using double and triple phase contrast acquisition methods.

Conventional chemical shift magnetic resonance (MR) imaging with the phase contrast technique has a number of limitations with respect to quantitative accuracy. The hypothesis of this study is that the accuracy of phase contrast chemical shift MR may be improved by increasing the number of basis images from two to three. Water and fat images were obtained from phantoms and volunteers with a 1.5 T MR system using double and triple acquisition phase contrast chemical shift methods. Longitudinal relaxation time and relative water and fat content were calculated from these basis images. The T1 relaxation times of the aqueous component of composite phantoms were determined more accurately using the triple acquisition method than with the double acquisition method. In vivo studies demonstrate that the triple acquisition method separated fat and water signals more accurately and showed less field inhomogeneity dependence than the modified double acquisition method. The new method also provided a map of static field magnetic inhomogeneity and tissue magnetic susceptibility. The triple acquisition phase contrast chemical shift imaging technique should improve the prospect for quantitative tissue characterization in clinical MR.

Size and fat content of gynes in relation to the mode of colony founding in ants (Hymenoptera; Formicidae).

In ants, there are two main processes of colony founding, the independent and the dependent modes. In the first case young queens start colony founding without the help of workers, whereas in the second case they are accompanied by workers. To determine the relation between the mode of colony founding and the physiology of queens, we collected mature gynes of 24 ant species. Mature gynes of species utilizing independent colony founding had a far higher relative fat content than gynes of species employing dependent colony founding. These fat reserves are stored during the period of maturation, i.e. between the time of emergence and mating, and serve as fuel during the time of colony founding to nurture the queen and the brood. Gynes of species founding independently but non claustrally were found to have a relative fat content intermediate between the values found for gynes founding independently and those founding dependently. This suggests that such gynes rely partially on their fat reserves and partially on the energy provided by prey they collect to nurture themselves and the first brood during the time of colony founding. Study of the fat content of mature gynes of all species has shown that it gives a good indication of the mode of colony founding.