Different Levels Of Fat Research Articles

Proteolytic and ACE-inhibitory activities of probiotic yogurt containing non-viable bacteria as affected by different levels of fat, inulin and starter culture.

In this study, the effects of fat (0.5%, 3.2% and 5.0%), inulin (0.0 and 1.0%) and starter culture (0.0%, 0.5%, 1.0% and 1.5%) on the angiotensin converting enzyme (ACE)-inhibitory activity of probiotic yogurt containing non-viable bacteria were assessed. Proteolytic activities of bacteria were also investigated. Yogurts were prepared either using a sole yogurt commercial culture including Streptococcus thermophilus and Lactobacillus delbrueckii subs. bulgaricus or bifidobacterium animalis BB-12 and Lactobacillus acidophilus La5 in addition to yogurt culture. Relative degrees of proteolysis were found to be considerably higher in yogurt samples than UHT milk as the control. Both regular and probiotic yogurts showed considerable ACE-inhibitory activities. Results showed that degree of proteolysis was not influenced by different fat contents, while was increased by high concentration of starter culture (1.5% w/w) and reduced by inulin (1% w/w). ACE-inhibitory activities of yogurt were also negatively affected by the presence of inulin and high levels of fat (5% w/w). Moreover, yogurt containing probiotic bacteria showed higher inhibitory against ACE in comparison to the yogurt prepared with non-probiotic strains.

Effect of different levels of fat and inulin on the microbial growth and metabolites in probiotic yogurt containing nonviable bacteria

SummaryEffects of different levels of fat and inulin on bacterial cell counts, degree of proteolysis and concentrations of organic acids in the yogurt containing inactivated cells of probiotic strains Bifidobacterium animalis and Lactobacillus acidophilus were investigated. Results showed that both L. acidophilus and B. animalis grew well in the yogurt samples reaching cell counts higher than 106 CFU mL−1 at the final pH of 4.5. Inulin at the concentration of 1% had no significant effects on the production of organic acids and cell counts of L. acidophilus, but promoted the growth of B. animalis with a reduction in the degree of proteolysis. Generally, different fat levels showed significant effects on the production of organic acids and nonsignificant effects on the cell counts of probiotic bacteria and degree of proteolysis. In case of lactic acid, the ratio of L‐ (+)to D‐ (−) isomer ranged from 50/50 to 80/20 in yogurt samples.

Effects of dietary vegetal fatty acid and fat content on growth and acclimation to Caspian Sea water in Caspian brown trout (Salmo trutta caspius) parr

This study assessed the effects of dietary fat level and source on growth performance, and seawater acclimation of the Caspian brown trout. Tuna fish oil and a blend of canola and soybean oils (85:15) with different levels of fat (LF: 10% and HF: 20%) were made to produce four different diets. The diets were labeled accordingly: LFFO (low fat fish oil), LFVO (low fat vegetal oil), HFFO (high fat fish oil) and HFVO (high fat vegetable oil). Each diet was fed to Caspian brown trout parr (~10g) for 60days. Both diets with vegetable oil base and high dietary fat (i.e. 20%) improved the growth performance, only the fishes fed a LFFO diet gained significantly less weight than the ones fed the other diets (P<0.05). The seawater acclimation was assessed by a gill Na+K+-ATPase immunolocalization (chloride cells number, size and area ratio) and by measuring the concentrations of serum chloride, sodium, magnesium, cortisol and glucose before transferring the fishes to seawater as well as 5days later. The fish fed with the test diets had no significant difference in chloride concentration but magnesium concentration significantly increased in all treatments after the seawater transfer. Sodium concentration increased significantly (P<0.05) only in fish fed the LFFO diet after the seawater transfer. Nor was there any difference in the number of filament chloride cells, but the fish fed this LFFO diet showed low salt secretion ability in SW due to the smaller size and area ratio of the filament chloride cells. The cortisol increased significantly only with the HFVO treatment after transfer to seawater (P<0.05). This experiment provides evidence that, due to higher energy supply, favorable fatty acids for energy production and facilitating better acclimation of the fish to Caspian Sea water, a high dietary fat level with vegetable oil (HFVO) meet adequately the essential nutritional requirements of the Caspian brown trout parr.

Morphological and physiological evaluation of common carp (Cyprinus carpio L., 1758) fed extruded compound feeds containing different fat levels

The study was carried out to examine morphological and physiological effects of different levels of fat in compound extruded feed for carp. A 90 days experiment was performed in tanks with water flow 0.34 L min−1, stocked each with 29 specimens of carp, average weight 15.4 ± 4.2 g. The fish was fed 3 diets containing 38 % protein and 8, 12 or 16 % of fat (feed L8, L12, and L16, respectively). Body weight gain, specific growth rate, food conversion ratio, feed efficiency ratio, condition factor, liver and intestine histology and morphometry and some blood biochemical parameters were analysed. At the end of the experiment, a difference was established between the fish fed L8 feed compared to carp fed L12 and L16 feed for all growth parameters. For several other parameters, nuclear area of hepatocytes, nuclear/cytoplasm ratio, enterocytes height and intestinal folds’ length, a difference between carp fed feed L8 compared to feed L16 was found. The histological analysis revealed that normal structure of the liver and intestine prevailed, but changes were observed regardless of the diet type. In the hepatopancreas, more prominent changes were found around pancreatic tissue—particularly, increased number and size of adipocytes. Although blood biochemical parameters were within normal values, a difference between L8 and L16 diet-fed carp was found for plasma levels of triglycerides and total proteins. According to the results obtained in this study, the best results were achieved using a feed with 8 % fat.

The Effect of Soy Fiber Addition on the Quality of Fermented Sausages at Low‐Fat Content

AbstractFermented sausages with different levels of fat and soy fiber were manufactured: control (15% fat), FS1 (10% fat and 1% soy fiber) and FS2 (10% fat and 2% soy fiber). During manufacturing, the physicochemical and microbiological parameters were assessed. The final products were submitted to a consumer study, and volatile compounds were extracted by solid‐phase microextraction and analyzed by gas chromatography/mass spectometry. FS1 and FS2 presented a final fat reduction of nearly 40%. There was no change in the manufacturing process. However, an addition of 2% soy fiber detracted from the sensory quality. Volatile compounds from lipid oxidation were reduced, and volatile compounds from carbohydrate and amino acid catabolism were increased in the modified fermented sausages. To conclude, fermented sausages with healthier characteristics can be produced without quality loss by reducing fat from 15 to 10% and by adding 1% soy fiber.Practical ApplicationsFermented sausages are consumed worldwide, especially in Brazil; it has a significant place in the population's diet. Therefore, the fat reduction in these products provides opportunities for the processing industry to add up healthier consumption appeals. In this study, the use of soy fiber in low‐fat fermented sausages was investigated in order to improve nutritional characteristics without affecting sensory properties.

Replacing Soybean Oil in the Finisher Phase with Different Levels of Dry Protected Plant Fat and Two Forms of Feed and their Effect on Performance, Carcass Quality and Blood Parameters of Broilers

An experiment was conducted to evaluate the effect of different levels of dry fat (dried palm oil) as an energy source and two feed forms (mash and pelleted)used in the finisher stage on growth performance, carcass traits, meat quality and blood serum metabolites of broiler chickens. A total of 450 straight-run Lohmann broiler chicks reared in an open-sided house and fed corn-soybean meal based diet with SBM oil as a source of energy from 1-28d of age. On d 28 birds were randomly assigned to 6 dietary treatments of 3 different levels of dry fat (2, 4 and 6%) and 2 forms of feed in 3 x 2 factorial arrangements. Each treatment has 3 replicates with 25 birds each (75/treatment). Experiment lasted for 42d. Processing yields and cut-ups were determined on d 42 in addition to meat quality traits and serum lipid levels. The different% of dietary fat did not improve growth performance with the interaction of fat level and feed form. But it was highly significant (P<0.05) with pelleted feed. Also significant higher difference (P<0.05) was shown in heart% with 2% fat and gizzard% between mash and pelleted feed (1.44 vs. 1.19) and with 2% fat mash feed. Breast% had a higher significant result (P<0.05) in mash feed. Abdominal fat% at 4% fat was significantly lower than 2 and 6%. Different significance were shown in meat analysis such as DM, fat and ash% with the different levels of fat and forms of feed. No significant differences were shown in blood parameters such as LDL, HDL, Cholesterol and Triglycerides.

IMPACT OF SAMPLE THICKNESS ON DESCRIPTIVE TEXTURE ANALYSIS OF CHEDDAR CHEESE

AbstractCheeses are available with different levels of fat and in different sizes and shapes (e.g., slices or cubes). This research investigated the effect of moving from a slice to a cube (constant 2‐D surface area, increased volume) on textural evaluation of Cheddar cheese at three different fat levels using both descriptive sensory analysis and consumer testing. Thin slices (2 mm thickness) were generally judged to be less firm and hard than thicker (8–20 mm) samples. However, there was no difference because of sample thickness in texture terms evaluated after five chews. Consumer liking (flavor, texture and overall) was not altered by sample thickness and decreased with fat reduction. Consumers preferred large sized (8 and 14 mm) samples over the thin slices. The potential benefit from a less hard, thin slice did not result in improved preference. It can be concluded that sample size does not alter the overall sensory perception such that differences because of fat content are diminished.Practical ApplicationsSensory analysis requires a choice in sample volume and shape. Some foods, such as cheese, are sold in a range of sizes, varying from slices to cubes. This research was designed to determine if sample size altered the textural perception of Cheddar cheese. Descriptive analysis indicated that slices, the thinnest sample, were generally rated as less firm/hard, but there was no consistent sample size effect on terms evaluated after chewing. Consumer testing showed that differences in liking (flavor, texture and overall) were due to fat level alone and not altered by sample size.

Effects of Dehulled, Crushed and Untreated Whole-Grain Paddy Rice on Growth Performance in Broiler Chickens

Experiments were conducted to determine the effects of different types of paddy rice (dehulled, crushed and untreated whole-grain forms) on growth performance in broiler chickens. In Experiment 1, a control diet containing 41.6% corn (control), and three experimental diets containing 40.7% dehulled, 43% crushed or 43% whole-grain paddy rice, were formulated to be iso-caloric (3,100 kcal/kg ME) and iso-nitrogenous (20% crude protein), but to contain different levels of fat (6%, 5.6%, 10.7%, 10.7%, respectively). Groups of 0-day-old chickens were the fed experimental diets ad libitum for 28 d. The average final body weight of groups fed the crushed and untreated whole-grain paddy rice was significantly lower (P<0.05) than that of the control group, but that of dehulled rice-fed group was slightly higher than the control group. This finding implies that the growth retardation seen with crushed or untreated whole rice could be caused by the feed intake-reduction due to the fat addition to the experimental diets. In Experiment 2, the control diet containing corn and the experimental diets containing dehulled and untreated whole-grain paddy rice were formulated to contain similar levels of fat (5.6-6%) and to be iso-nitrogenous (20%), but not to be iso-caloric. As a result, the average body weight gain of the whole-grain rice-fed chickens showed a considerable increase compared with the control diet-fed chickens even though the energy content of the former diet was only about 90% that of the control diet. It is concluded that whole-grain paddy rice could serve as a valuable constituent of broiler chicken feed, but that excess fat in the diet to maintain the ME content (3,100 kcal/g) could have a negative effect on growth performance.

The effects of different levels of orange fiber and fat on microbiological, physical, chemical and sensorial properties of sucuk

The effects of orange fiber and fat levels on the physical, chemical and microbiological properties of sucuk (Turkish dry-fermented sausage) were investigated. Different levels of orange fiber (0, 2 and 4%) were added to sucuk batters with different levels of fat (10, 15 and 20%). Sucuk samples were analyzed during ripening. Lactic acid bacteria, Micrococcus/ Staphylococcus and pH value were effected very significantly by orange fiber. Orange fiber caused a decrease in residual nitrite levels and an increase in the TBARS values. L ∗ and b ∗ values of sucuk samples increased with the use of fiber. Fiber use also decreased the cooking loss. No statistically significant difference was found between control and 2% fiber groups in terms of texture, color, odor taste and general acceptability scores. While fat levels had significant effects on cooking loss, taste and L ∗ values, ripening time effected all analyzed parameters.

Practical use of surimi-like material made from porcine longissimus dorsi muscle for the production of low-fat pork patties

This study evaluates the effect of replacing fat with surimi-like material (SLM) made from the porcine longissimus dorsi muscle on the physicochemical and sensory characteristics of pork patties. Pork patties were produced with different levels of fat and SLM using a commercial method. Pork patties produced with 20% SLM had the lowest fat content (1.76%, P < 0.001), and had a higher cooking yield (87.41 vs. 78.57%, P < 0.05) and less shrinkage (4.01 vs. 9.02%, P < 0.001) than patties produced with 20% back-fat (control). Moreover, patties produced with SLM exhibited more acceptable organoleptic characteristics, including tenderness ( P < 0.01) and overall acceptability ( P < 0.001), than full-fat control patties. These results indicated that SLM cannot only be used as a fat replacer, but that it also improves the physicochemical and sensory characteristics of low-fat pork patties.

Evaluation of goat mortadella prepared with different levels of fat and goat meat from discarded animals

The objectives of this study were to develop a value added product, goat mortadella, using meat from discarded animals; to evaluate pork fat at various levels of inclusion in mortadella in an effort to reduce the fat content of the product; to determine consumer acceptability; and to determine the physico-chemical properties of this goat product. Three goat mortadella formulations were manufactured containing 10, 20 and 30% pork fat. The sensory characteristics, microbiological and proximate analysis, starch, chlorides, pH, water activity (Aw), water holding capacity (WHC), emulsion stability and CIE colour characteristics (i.e. a*, b* and L*) of the mortadella were evaluated. The total number of thermotolerant coliforms, Staphylococcus aureus, Salmonella and Clostridium sulphite-reducers in the goat mortadella were in accordance with Brazilian legislation. Consumer panellists detected significant differences (P<0.05) in appearance, colour, odour, flavour, texture and overall acceptance among the goat mortadella formulations. The goat mortadella prepared with 10% fat was rated the highest. In addition, approximately 70% of the panellists commented that they would purchase the goat mortadella. The percentages of moisture and protein were reduced as the percentages of fat added to the formulation increased. The goat mortadella with 30% fat had higher (P<0.05) fat, ash, emulsion stability, WHC and b* contents than those with 10 and 20% fat. The use of meat from discarded goats in the preparation of mortadella allows getting the most from this material, and the addition of 10% fat resulted in a goat mortadella with better acceptance and lowest fat content.

Effects of antibiotic and probiotic supplementation to diets containing fat on broiler performance

The use of supplementary fat in commercial poultry diets has been wide-spread since the 1960s. In addition to their value as a dense source of energy, supplemental fats are an excellent source of essential fatty acids and enhance the absorption of fat soluble vitamins. The efficiency of nutrient digestion in poultry largely depends on the microorganisms which live naturally in its digestive tract (Apajalahti et al. 2003). It has been reported that intestinal microflora influences the absorption of fats (Pesti, 2002).Today, antibiotics and probiotics are used for manipulating the gut microflora in poultry production and act as growth-promoting agents. Thus, using these growth promoters (GP) will probably affect nutrients absorption, especially of dietary fats. The aim of this study was to evaluate the effects of supplementary antibiotics and probiotics in diets containing different levels of fat on broiler performance.

The Effect of Monensin and Supplemental Fat on Growth Performance, Blood Metabolites and Commercial Productivity of Zel Lamb

This research was conducted in order to investigate the effects of supplemental fat and monensin on the level of Dry Matter Intake (DMI), Average Daily Gain (ADG), final weight, Feed Conversion Ratio (FCR), blood glucose level, Blood Urea Nitrogen (BUN), calcium, phosphor, triglyceride, cholesterol and crude protein of the Zel lambs; as well as commercial effects of monensin and supplemental fat on the lambs fattening. Most of the time, ordinary food does not suffice the animals needs. Thus, using high-energy materials like fats are important in programming the diets. Moreover, adding some materials to the animal diets could increase the animal efficiency and the products quality. Hormones, antibiotics, ionophores are amongst the most important additives affecting income in the lamb fattening industry. Monensin is the first ionophore component proven to be effective in increasing efficiency of ruminant animals. Twenty-four male Zel lambs were used with an age average of 3-4 months and an initial live weight of 21.94 +/- 0.642 kg. A period of eleven days was considered as the adaptation time and the experiment was carried on during three 21-day phases (totally 63 days). The variables for this study were supplemental fat on two levels of 0 and 4% and monensin on tree levels of 0, 20 and 40 mg kg(-1) on a dry matter basis. There were four repetitions for each treatment. The results of this research reveal that different levels of fat and monensin do not have significant effect on DMI, ADG, FCR and level of glucose. The food treatment had significant effect on final weight, calcium level, BUN, phosphor, triglyceride, cholesterol and CP (p < 0.05). Also, they affect commercial productivity.

Rheological, microstructural and sensory characterization of low-fat and whole milk set yoghurt as influenced by inulin addition

The effect of inulin addition (0–4%) upon texture and microstructure of set yoghurt with different levels of fat (0.2%–3.5%) was investigated. A two-factor experimental design with four treatments was used for data analysis. Skimmed milk with various inulin and cream concentrations was standardized to 4% protein content, homogenized, heated to 92 °C and fermented at 42 °C until a pH of 4.6 was reached. The chemical composition, pH, consistency and microstructure properties of the yoghurts were analysed after 6 days of storage at 5 °C. The statistical analysis showed that inulin and fat significantly affected the rheological and sensory results. Higher yield stress, “firmness” and “creaminess” values were observed in yoghurt produced with higher inulin additions, whereas the pH value was not affected. A significant correlation was found between yield stress and sensory determined firmness ( r = 0.91). The microstructure examined by confocal laser scanning microscopy (CLSM) was only slightly affected by the concentrations of inulin in the range studied, possibly due to weak protein interactions between the inulin and the milk protein network.

Study the Effects of Different Levels of Fat and L-carnitine on Performance, Carcass Characteristics and Serum Composition of Broiler Chicks

An experiment was conducted in order to study the effect of 3 levels of fat (1, 3, 5%) and 2 levels of L-camitine (0 and 250 mg kg(-1)) on 360 male Ross broiler chicks in a factorial arrangement (2 x 3) with completely randomized design with 6 treatments, 4 replicates and 15 chicks in each replicates. All diets were isocaloric and isonitrogenous and were fed to chicks from 1 to 42 days of ages. During the experiment feed intake, body weight gain and feed conversion ratio were measured weekly. Mortality was measured throughout the experiment. At 42 days of ages 4 birds from each treatment were slaughtered for determination of carcass characteristics and serum composition. Data of the experiment were analyzed by GLM procedure of SAS. Increasing of fat in the diets significantly improved performance of chicks in grower (22 to 42 days) and whole period (1 to 42 days) of the experiment (p < 0.05). Chicks fed with diets containing 3% fat had the highest breast meat and lowest abdominal fat percentage (p < 0.05). Adding L-carnitine to diets had not significant effect on performance and carcass characteristics. Interaction between fat and L-carnitine was significant on liver weight (p < 0.05). The levels of triglyceride (TG) and glucose in blood serum were affected by increasing of dietary fat (p < 0.05). Adding L-carnitine to diets significantly decreased the level of serum triglyceride, cholesterol and VLDL (p < 0.05). Dietary treatments had not significant effect on mortality.

Quality and shelf life evaluation of fermented sausages of buffalo meat with different levels of heart and fat

Investigations were carried to study the effect of heart incorporation (0%, 15% and 20%) and increasing levels of fat (20% and 25%) on physicochemical (pH, moisture content and thiobarbituric acid, TBA number) and microbiological (total plate count and yeast and mold count) quality and shelf life of semi dry sausages of buffalo meat during refrigerated storage (4 °C). Different levels of fat significantly ( p < 0.05) increased the pH of the sausage samples. However different levels of heart incorporation did not significantly ( p < 0.05) affect pH, moisture content and TBA number of sausage samples. Fresh samples had pH, moisture content and TBA number in the range of 5.15–5.28, 42.4–47.4% and 0.073–0.134 respectively. Refrigerated storage significantly ( p < 0.05) increased TBA number of control samples while storage did not significantly ( p < 0.05) increase the TBA number of sodium ascorbate (SA) treated samples. Total plate counts of twelve sausage samples were f under the TFTC (too few to count) limit at the initial stage. Incorporation of different levels of heart and also increasing levels of fat did not significantly ( p < 0.05) increase the log TPC/g values. Yeast and molds were not detected in twelve samples of semi dry fermented sausages in their fresh condition. Storage revealed that there was a consistent decrease in pH, and moisture content. Refrigerated storage significantly ( p < 0.05) reduced both pH and moisture contents. TBA number and total plate counts and yeast and mold counts of controls were found to increase significantly ( p < 0.05) during refrigerated storage. However, in SA treated sausage, only TPC and yeast and mold count significantly ( p < 0.05) increased during refrigerated storage. Shelf life of the sausages was found to be 60 days under refrigerated storage (4 °C).

The characteristics of beef patties containing different levels of fat and oat flour

SummaryThree concentrations of oat flour (OF), 0, 2 and 4% (w/w), were added to beef patties which had either 5, 10 or 20% fat levels. Raw and cooked patties were analysed for protein, fat, moisture, ash and pH. Patties were further evaluated for cooking characteristics, colour parameters (L*, a*, b*) and sensory properties. Moisture content decreased in raw patties as a result of the addition of OF but OF increased the moisture content of cooked patties. OF addition did not change the protein, fat and ash contents of either raw or cooked patties. Increasing fat concentration decreased cooking yield. OF improved the cooking characteristics of patties. Reducing the fat significantly decreased the lightness values of patties. Patties with OF had slightly higher b* values than control treatments. Increasing fat level increased juiciness, flavour and texture scores and 4% OF increased the juiciness scores, OF had no effect on other sensory properties.

Effects of Supplemental Fat on Performance of Laying Hens

2 Abstract: 360 Hy-line W36 hens were fed the diets with four different levels of fat (0, 1.5, 3.0 and 4.5%) to determine different levels of supplemental fat on performance of laying hens from 35 to 44 week of age. Hy- line W-36 hens at 35 week of age were randomly assigned into 4 dietary treatments (6 replicates of 15 birds per treatment). As fat level increased, feed intake linearly decreased from 99.1 to 93.5, resulting a 5.7 % decrease in feed intake. As fat level increased, feed conversion linearly decreased. Increasing fat had no effects on egg production, egg weight, egg mass, egg specific gravity, and body weight of laying hens. Increasing fat improved nutrient (protein, amino acids, calcium, and phosphorus) utilization. It may be a good choice to supplement high level of fat to improve protein (amino acids) utilization and to decrease cost of production especially when fat price is cheap and prices of protein source ingredients are expensive.

The effect of fat substitutes on the emulsion stability and sensory characteristics of reduced fat sesame paste/date syrup blends (reduced fat Halwa-Ardeh)

Abstract Halwa-Ardeh is a traditional food in Iran and Middle East countries, which is produced by crushing the dehulled sesame seeds and then mixing with a proper sweetener such as grape concentrate, date syrup, and honey. The oil content of this product is on the average of 57-65% (w/w). In this research, the effect of different levels of fat substitutes including guar gum (of 0.1, 0.15 and 0.2%), Xanthan (0.01, 0.015 and 0.02%), and modified starch (0.75, 1.25 and 1.75%) on the emulsion stability and sensory characteristics (oiliness, firmness, spreadability, adhesiveness, color, mouth coating, taste, and total acceptance) of reduced fat sesame paste/date syrup blends have been investigated. The results showed that all fat replacers at each substitution level (except for 0.02% substitution of xanthan gum) increased the emulsion stability of samples in comparison with the control. In addition, the sensory evaluation by panelists showed that the effect of fat substitutes at each level of substitution on sensory properties of many samples was not significant (α=5%), but all fat replacers improved the spreadability and firmness of samples compared to the control. Keywords: Sesame Paste; Date Syrup; Xanthan; Modified Starch; Guar; Emulsion Stability; Sensory Properties

Quantitative magnetic resonance (QMR) method for bone and whole-body-composition analysis.

to evaluate the applicability, precision, and accuracy of the new EchoMRI quantitative magnetic resonance (QMR) method for in-vitro bovine bone analysis and in-vivo whole-body-composition analysis of conscious live mice. bovine tibia bone samples were measured by QMR and dual-energy X-ray adsorptiometry (DEXA). Repeated measures of whole-body composition were made using live and dead mice with different levels of fat by QMR and DEXA and by classic chemical analysis of the mouse carcass. bone-mineral density (BMD) and bone-mineral content (BMC) measured in bovine tibia by QMR and DEXA were highly correlated. Precision of fat and lean measurement in mice was found to be better for QMR than for DEXA. The coefficient of variation ( CV) for fat was 0.34-0.71% for QMR compared with 3.06-12.60% for DEXA. QMR offers more specific parameters of bone structure than does DEXA. QMR and DEXA did not differ in the total amount of fat detected in live mice but QMR had improved precision. QMR was superior to DEXA in measuring fat in very small mice. in bone tissue there is a strong correlation between hydrogen NMR signal and bone-mineral density as measured by X-ray. QMR provides a very precise, accurate, fast, and easy to use method for determining fat and lean mass of mice without the need for anesthesia. Its ability to detect differences and monitor changes in body composition in mice with great precision should be of great value in characterizing phenotypes and studying drugs affecting obesity.