Body Fat Mobilization Research Articles

Relationship of Body Condition Score and Oxidant Stress on Tumor Necrosis Factor Expression in Dairy Cattle

Excessive mobilization of body fat in the dairy cow is a well-known risk factor for poor fertility, metabolic problems and increased susceptibility to a variety of infectious diseases. In humans, obese patients have an enhanced production of pro-inflammatory cytokines (such as Tumor Necrosis Factor-alpha and Interleukin- 6), which has been recognized to induce a pro-inflammatory environment and facilitate oxidative damage, leading to the initiation and progression of an array of diseases. The purpose of this study was to investigate if a similar relationship exists in the dairy cow between obesity, oxidative stress, pro-inflammatory cytokines and susceptibility to disease.

Combined effects of oral oleoyl-estrone and limited food intake on body composition of young overweight male rats

The combined effects of limited food intake and OE treatment have been analysed in order to determine whether hypocaloric diets enhance the slimming effects of OE on mature overweight male rats. Two levels of dietary limitation at 50 and 25% of a standard intake were established, roughly corresponding to the human LCDs and VLCDs. Wistar male rats (6 weeks old) were made overweight by a cafeteria diet. After transition to standard diet, they were subjected to food restriction: down to 50 or 25% with respect to the transition period. Half the animals were given daily oral gavages of 10 nmol/g oleoyl-estrone (OE), and the rest received only the vehicle during 10 days. Changes in weight and body composition: water, lipid, protein or gross energy were determined by comparing the final pool size with that of day 0, calculated from the initial body weight and the composition of untreated rats. Energy and nitrogen balances were estimated. Plasma levels of metabolites and hormones were also measured. OE induced changes in body composition similar to those elicited by a 50% reduction in food, with massive loss of lipid and energy. OE-treated rats ate less than the controls, but additional effects on body composition on reduced diet were minimal. OE improved metabolic homoeostasis: better maintained glycaemia, lower cholesterol and shallower hormonal changes, but at the expense of slightly increased protein mobilisation. The data presented suggest that no advantages are accomplished by combining OE treatment and hypocaloric diets compared with OE alone, at least under the experimental conditions tested, since the effects were not additive. Despite OE affecting food intake, mechanisms other than that are deemed responsible for the mobilisation of body fat, since intake alone cannot explain the effects on body weight, nor the metabolic and hormonal changes in OE-treated rats. It is concluded that the combination of food restriction and OE may result in unwanted increased protein mobilisation with no synergy between both slimming treatments.

Inhibition of ovulation in the postpartum cow and the lactating sow

Increased genetic selection and capacity for milk production in dairy cows has been associated with a decline in fertility. Following parturition, nutritional requirements increase rapidly with milk production and the resulting negative energy balance (NEBAL) extends for 8–10 weeks of early lactation. NEBAL delays the timing of first ovulation through attenuation of LH pulse frequency and low levels of blood glucose, insulin and IGF-I that collectively limit oestrogen production by dominant follicles. NEBAL results in mobilization of adipose tissue and loss of body condition score (BCS), which is strongly associated with the length of the postpartum anovulatory period. Failure of ovulation of the first wave dominant follicle is associated with elevated nonesterified fatty acids and ketones in plasma and greater accumulation of triglycerides in the liver during the first 3 weeks of lactation. NEBAL is related to lower fertility in dairy cows both through inhibition of ovulation in early lactation and effects exerted later during the breeding period. Management strategies to minimize the inhibitory effects of NEBAL on first ovulation should begin during the prepartum transition period and include maintaining moderate BCS and energy intake through parturition. Modern sows have been improved genetically for higher productivity including ovulation rate, litter size and milk production. Peak milk yield is achieved within 10 days after farrowing with consequent massive mobilization of body fat and protein mass. Conservation of body protein mass (< 12% loss) during the first lactation minimizes the weaning to estrus interval by advancing ovarian follicular development toward ovulation. The lysine requirement in early lactation is extraordinary. Plasma insulin and IGF-I concentrations seem unrelated to the observed differences in ovarian follicular development. Overall, NEBAL inhibits ovulation in both high producing cows and sows, but there are species differences in response to protein losses and hormonal interactions.

Feeding- and management-related diseases in the transition cow: Physiological adaptations around calving and strategies to reduce feeding-related diseases

The objective of this review was to address the basis for and prevention of selected diseases (fatty liver, ketosis, rumen acidosis and displaced abomasums) that are feeding- and management-related and frequent in periparturient cows. The focus has been to discuss (1) the general physiological regulation and adaptations that are believed to be important for a successful transition to lactation, (2) for each disease the disease incidence rate, risk factors, aetiology and pathophysiology and (3) feeding and management strategies to prevent diseases. Unfortunately, few studies have documented prevention strategies and they consequently need to be developed based on risk factors and knowledge of the aetiology of the diseases. Strategies to prevent these diseases are therefore based on major factors directly or indirectly increasing the risk of fatty liver, ketosis, acidosis and displaced abomasum—factors such as over-conditioning at calving, excessive mobilisation of body fat, low nutrient intake, nutrient or diet specific factors and management and environmental stress. Finally, thoughts are presented on how prevention potentially could be improved in the future. It is suggested that there should be greater focus on individual animals in order to identify “risk animals”. Status-oriented strategies for optimising dairy cow health, reproduction and production are suggested that aims at securing a desirable status of epithelia, metabolism and immune function in different cells, tissues or organs through surveillance and health and production management based on indicators.

Effects of l-carnitine supplementation on milk production, litter gains and back-fat thickness in sows with a low energy and protein intake during lactation

The present study investigated the effect of L-carnitine supplementation during pregnancy (125 mg/d) and lactation (250 mg/d) on milk production, litter gains and back-fat thickness in sows fed a low-energy and low-protein diet during lactation. Sows supplemented with L-carnitine produced more milk on days 11 and 18 of lactation (+18 %; P<0.05) and had higher litter gains during suckling (+20 %; P<0.01) than control sows. Loss of body weight during lactation was similar in both groups, but sows supplemented with L-carnitine had a greater reduction of back-fat thickness (+45 %; P<0.05) during lactation than control sows. In conclusion, this study shows that L-carnitine increases milk production and litter gains in sows in a strongly negative energy and N balance, and enhances body fat mobilisation.

Effect of Body Fatness and Glucogenic Supplement on Lipid and Protein Mobilization and Plasma Leptin in Dairy Cows

Twenty-four multiparous Ayrshire cows were used in an experiment to test the effect of body fatness and glucogenic supplement, fed during the transition period, on lipid and protein mobilization and plasma hormone concentrations. Eight weeks before their expected calving date, the cows were divided into blocks of 4. Two cows with the highest body condition score within each block were then allocated to a test (T) group and the other 2 cows to a control (C) group. To scale up the differences between fatter and thinner cows, the estimated energy allowance was 40% higher in group T than in group C between d 56 and 21 prepartum. For the final 3wk before calving, all the cows were fed according to energy recommendations for pregnant cows. Within C and T groups and blocks, cows were randomly assigned into groups with (G1) or without (G0) glucogenic supplement. Division to G0 and G1 groups was made 2wk before the expected calving and continued for 56 d postpartum. After calving, all the cows received grass silage ad libitum and a common daily concentrate allowance. No significant differences were detected in feed intake and milk yield between C and T. The T groups showed an earlier rise of nonesterified fatty acids as calving approached and had higher plasma nonesterified fatty acids during the final week of pregnancy and lactation wk 1 to 3. At the same time, adipose tissue samples from fatter cows tended to show higher in vitro lipolytic responses to added norepinephrine, as monitored by glycerol release. Protein mobilization was elevated during the final week of pregnancy and tended to be more increased in fatter cows. Glucogenic supplement did not decrease lipid or protein mobilization. Fatter cows had higher plasma leptin concentration prepartum, showed a more pronounced decrease in leptin concentration near calving, and had higher plasma leptin concentration after calving. In conclusion, fatter cows initiated more extensive mobilization of body fat before calving and this continued during the first lactation weeks. Plasma leptin concentration in early-lactation cows was associated with body fatness and not with estimated energy balance.

Body weight of mares and foals, estrous cycles and plasma glucose concentration in lactating and non-lactating Lipizzaner mares

This study summarizes weight development, plasma glucose concentrations and reproductive parameters in lactating ( n=46) and non-lactating Lipizzaner mares ( n=11) throughout the breeding season. It was the aim of the study to analyse if an energy deficit with possible effects on reproductive functions occurs at any time during the first 4 months of gestation. Mean gestation length was 334.3±7.3 days. Gestation of foals born in May/June was shorter ( P<0.01) than for foals born in March/April. Out of the 46 lactating mares, 44 ovulated between Days 8 and 18 postpartum and two mares ovulated on days 30 and 145, respectively. Pregnant mares were significantly ( P<0.001) heavier (600.1±5.3 kg) than non-pregnant mares (521.8±10.0 kg) at the beginning of the study. Birth resulted in weight reduction of 64.8±2.4 kg. During the first 2 weeks postpartum mares lost on average 3.0±1.8 kg and in the following 2 weeks gained 3.6±1.4 kg of weight. Thereafter, weight increased slightly but continuously ( P<0.01). At no time after foaling, weight differed significantly between groups. Weight of the foals three days after birth varied between 29 and 67 kg (53.7±1.1 kg). Average daily weight gain of foals was relatively constant throughout the study period (1.15±0.17 kg). Although lactation at no time was associated with a major weight loss, it had clear effects on energy metabolism as shown by constantly lower plasma glucose concentrations in lactating mares. Glucose concentrations decreased after foaling and were significantly lower in lactating mares from Weeks 3 to 16 after foaling than at corresponding times in non-lactating mares ( P<0.01). However, glucose concentrations were still within the physiological range. Mares seem to be able to compensate energy losses during lactation mainly by increasing feed intake and not by mobilisation of body fat.

EFFECTS OF LARGE EXERCISE-INDUCED WEIGHT LOSS ON ABDOMINAL FAT AND LIPID LEVELS IN OBESE MALES

PURPOSE: This study examined whether reductions in abdominal fat following large exercise-induced weight loss were related to changes in lipid levels in obese Singaporean males, independent of changes in weight. METHODS: 20 obese males (mean age 19.8 ± 0.6yrs) were evaluated before (pre-training) and after (post-training) four months of regimented training in the Singapore Armed Forces. 30 obese males (mean age19.2 ± 1.3yrs) without training were monitored as control subjects. Fat free mass (FFM), fat mass (FM) and per cent (%) body fat were determined from skinfold measurements. Body mass index (BMI) and waist hip ratio (WHR) were calculated from height, weight and circumferences taken pre- and post-training using standard methods. Blood samples were collected after an overnight fast to determine plasma lipid levels. Differences between pre- and post-training responses were analyzed with a paired t-test. RESULTS: From pre- to post-training, there were decreases in waist circumference and hip circumference (P < 0.001), the decrease in WHR (P < 0.001) indicating a greater mobilization of upper body fat and a preferential loss of fat from this region. Exercise-induced weight loss (12kg) decreased CHD risk as indicated by the reductions in total cholesterol, LDL-C and Apo B (all P < 0.001). However, there was no evidence that the pre-training measures of WHR or waist circumference were related to the pre-training measures of these risk factors, nor were there any relations between the changes in WHR and waist circumference and the changes in lipid levels that accompanied exercise-induced weight loss. In contrast, pre-training levels of metabolic variables were inversely related to the subsequent chang in each of these measures. Thus, those with the higher levels of lipids prior to training experienced the gratest improvements following weight loss. CONCLUSION: These data suggest that exercise-induced weight loss is associated with a reduction in abdominal obesity in men, but that changes in fat distribution may not be related to changes in cardiovascular risk factors.Table: No Caption Available

Changes in stress-related plasma metabolite concentrations in working Mashona cows on dietary supplementation

Effects of work stress and dietary supplementation on body condition score and plasma metabolite concentrations were determined in 16 multiparous Mashona cows in a smallholder crop–livestock farming area in Sanyati Communal Lands. The cows were divided into four treatment groups of equal numbers. These were: supplemented working (SW), supplemented non-working (SNW), non-supplemented working (NSW) and non-supplemented non-working (NSNW). Cows in the SW and NSW groups pulled carts with 400-l drums of water for a distance of 18 km five times each week for the 12 consecutive weeks of the experiment. During the experimental period, body condition scores were assessed at 2-weekly intervals and plasma metabolite concentrations determined in samples collected once per week. Imposing work reduced ( P<0.05) body condition score in the cows. In addition, work induced a decline ( P<0.05) in plasma glucose concentrations, and increased ( P<0.05) non-esterified fatty acids and serum urea levels circulating in blood. Supplementary feeding improved ( P<0.05) body condition score of cows. These results indicate that, using cows for draught results in the mobilisation of body fat and protein reserves, probably to supplement the nutrient demand for draught power. In addition, SW and NSW cows maintained their metabolite levels within the normal physiological ranges, indicating that, for the best welfare of cows that are used in the provision of draught, they should be given supplementary feed.

Beziehungen zwischen Futteraufnahme, Seitenspeckdicke und ausgewählten Merkmalen der Aufzuchtleistung laktierender Sauen

Abstract. Title of the paper: Relationship between feed intake, side fat thickness and special parameters of rearing Performance of lactating sows A total of 106 Camborough sows were used to study the relationship between feed intake, side fat thickness at the end of pregnancy, their change during lactation and special parameters of rearing Performance. Sows with a high side fat thickness at the end of pregnancy realised a lower feed intake during lactation (r = −0.206*) but a higher loss of side fat thickness (r = −0.499**) than sows with worse body condition. High feed intake during lactation stimulates a high number of weaned piglets (r = 0.299*) and the weight of weaned litter (r = 0.321*). The amount of feed intake in first week of lactation is most important for it. Generally, sows with a high predisposition for mobilisation of body fat and high intake of food during lactation realised the significant highest rearing Performance (r = 0.436***).

Ionophores for Dairy Cattle: Current Status and Future Outlook

Ionophores are used commercially throughout the world in the beef and poultry industries. Production efficiency of cattle is increased through alteration of rumen fermentation and control of protozoa that cause coccidiosis. Ionophores act by interrupting transmembrane movement and intracellular equilibrium of ions in certain classes of bacteria and protozoa that inhabit the gastrointestinal tract. The actions of ionophores provide a competitive advantage for certain microbes at the expense of others. In general, the metabolism of the selected microorganisms favors the host animal. Energy metabolism is enhanced through increased production of propionate among ruminal fatty acids with a concomitant reduction in methane. Ruminal degradation of peptides and amino acids is reduced, thereby increasing the flow of protein of dietary origin to the small intestine. Total flow of protein to the lower tract is often increased with ionophore feeding. Risk of digestive disorders such as bloat and acidosis that result from abnormal rumen fermentation is reduced, as are certain conditions caused by toxic products of fermentation, e.g., 3-methyl indole. Dry matter and nitrogen digestibilities are increased with ionophores, thereby providing environmental benefits. Monensin and lasalocid have been the most studied in research demonstrating benefits to the dairy cow. Ionophores enhance the glucose status of dairy cows through increased production of propionate. Many of the demonstrated benefits of ionophores are associated with enhancement of the energy status of the cow in the transition period and during early lactation. The benefits include less mobilization of body fat as evidenced by reduced blood nonesterified fatty acids and ketones and increased glucose. Animal manifestations include lower incidence of ketosis and displaced abomasum, reduced loss of body condition, increased milk production, and improved milk production efficiency.

EFFECT OF LARGE EXERCISE-INDUCED WEIGHT LOSS ON BODY COMPOSITION AND FAT DISTRIBUTION IN OBESE MALES

This study examined the effects of large exercise-induced weight loss on body composition and fat distribution in obese Singaporean males. 30 obese males (mean age 19.8 ± 0.6 yrs) were evaluated before (pre-training) and after (post-training) four months of regimented training in the Singapore Armed Forces. 30 obese (mean age 19.2 ± 1.3yrs) males without training were monitored as control subjects. Fat free mass (FFM), fat mass (FM) and per cent (%) body fat were determined from skinfold measurements. Body mass index (BMI) and waist hip ratio (WHR) were calculated from height, weight and circumference measures taken pre- and post-training using standard methods. Differences between pre- and post-training responses were analyzed with a paired t-test. Results are presented in the table below (values are Mean ± SD; ***P < 0.001) TABLE Subjects lost 12.0 ± 3.6 kg (P < 0.001) from pre- to post-training, which was attributable to a reduction in FM (P < 0.001), as FFM was unchanged. Significant changes were observed in the measures of body fat distribution. Both waist circumference and hip circumference decreased (P < 0.01), the reduction in waist circumference (13.7%) being greater than the reduction in hip circumference (7.7%) as reflected by the decrease in WHR (P < 0.001). These data reveal that large exercise induced weight losses are associated with a maintenance of FFM, unlike diet induced weight losses of the same magnitude. In addition, the significant reduction in WHR observed after training indicates a greater mobilization of upper body fat and a preferential loss of fat from this region. Thus, exercise-induced weight loss is associated with a reduction in abdominal obesity and a corresponding maintenance of FFM. Such effects on body composition should reduce disease risk and the eventual weight regain that typically follows diet-induced weight losses with obese subjects.Table

A low-fat diet but not food restriction improves lactational performance in obese rats.

Rats fed a high-fat diet before and during lactation have difficulty initiating lactation and have high pup mortality rates, low milk production and, consequently, poor pup growth. To determine if these adverse outcomes can be mitigated with dietary changes made after delivery, obese Sprague-Dawley rats (who had previously been fed a high-fat diet [AIN-93M, modified to contain 35% fat, w/w]) were assigned at parturition to continue to be fed this diet (HF) or switched to free access to a corresponding low-fat (LF) diet (AIN-93M, 4% fat w/w) or switched to the LF diet and restricted to consuming only 75% of ad libitum intake (LF/R). Dams lost weight during lactation, but weight loss was much less in the LF group (19g) than in the other two groups (47 and 59g, HF and LF/R, respectively). There was no appreciable change in body water; body fat decreased by about half in all groups, but most substantially in the LF/R group. Compared with the HF group, milk production was 50% higher in the LF group and 12% lower in the LF/R group. Milk lipid concentration tended to be higher and milk water concentration lower in the HF compared with the other two groups. Growth of the litters of the LF dams was significantly higher than both HF and LF/R dams. These results indicate that switching to a low-fat diet mitigates the negative effects of obesity and continued high-fat feeding on lactational performance and pup growth. Consumption of restricted quantities of a low-fat diet negatively affected milk production and failed to improve pup growth, despite the dams' mobilization of body fat in support of lactation.

Prolonged effects of modified sham feeding on energy substrate mobilization

Vagal stimulation in response to nutrients is reported to elicit an array of digestive and endocrine responses, including an alteration in postprandial lipid metabolism. The objective of this study was to assess whether neural stimulation could alter hormone and substrate metabolism during the late postprandial phase, with implications for body fat mobilization. Vagal stimulation was achieved by using the modified sham feeding (MSF) technique, in which nutrients are chewed and tasted but not swallowed. Ten healthy subjects were studied on 3 separate occasions, 4 wk apart. Five hours after a high-fat breakfast (56 g fat), the subjects were given 1 of 3 test meals allocated in random order: water, a lunch containing a modest amount of fat (38 g), or MSF (38 g fat). Blood was collected for 3 h poststimulus for hormone and metabolite analyses. Plasma insulin and pancreatic polypeptide concentrations peaked at 250% and 209% of baseline concentrations within 15 min of MSF. The plasma glucose concentration increased significantly (P = 0.038) in parallel with the changes observed in the plasma insulin concentration. The nonesterified fatty acid concentration was significantly suppressed (P: = 0.006); maximum suppression occurred at a mean time of 114 min after MSF. This fall in nonesterified fatty acid was accompanied by a fall in the plasma glucagon concentration from 122 to 85 pmol/L (P = 0.018) at a mean time of 113 min after MSF. Effects on substrate metabolism after MSF in the postprandial state differ from those usually reported in the postabsorptive state. The effects of MSF were prolonged beyond the period of the cephalic response and these may be relevant for longer-term metabolic regulation.

Energy metabolism and lipogenesis in humans

Data from an experiment with adult humans in which the energy metabolism was measured by indirect calorimetry were used in a biological model of nutrient oxidation, lipogenesis and retention at the whole body level. Six male and four female adult volunteers (53–90 kg body weight) were asked to estimate the amount of a fixed diet, which would cover their normal degree of satiation, corresponding to their requirement of metabolizable energy (ME) for maintenance. The ME intake in relation to metabolic body weight (kg 0.75) showed a great variation with 466 kJ in Group A ( n=2), 406 kJ in Group B ( n=5) and 379 kJ in Group C ( n=3). The heat production was lower than the ME intake in Group A and B, causing a positive energy retention about 1800 (Group A) and 525 kJ/d (Group B). In Group C heat production exceeded ME intake causing a negative retention of 1200 kJ and mobilization of body fat. Oxidation of protein contributed with 14% to the total heat production for all groups. Oxidation of carbohydrate contributed in Group A, B and C with 55, 45 and 41% while oxidation of fat contributed with reverse values of 31, 40 and 46%, respectively. Lipogenesis occurred in all participants with 900 kJ/day in Group B and 600 kJ/day in Group A and C, corresponding to 50 and 34 g carbohydrate entering the fat metabolism via de novo lipogenesis. The present results indicate that the rate of lipogenesis in adult humans depends on carbohydrate and energy supply from a diet.

Effects of Bovine Somatotropin and Evaporative Cooling Plus Shade on Lactation Performance of Cows During Summer Heat Stress

Thirty-two Holstein cows (8 per treatment) averaging 195 d in milk were assigned to 70 d of treatment on the basis of production during a 14-d pretreatment period, which was used for covariate analysis. The experiment was a randomized block design with a 2 × 2 factorial arrangement of treatments. Factors were normal shade or shade plus evaporative cooling with pressurized spray, plus with or without the administration of bovine somatotropin (bST). Cows receiving bST were injected with 500mg of bST every 14 d. All cows were fed the same total mixed rations twice daily at approximately 10% in excess of appetite, and water was offered free choice. There were no interactions between bST and the cooling system for any of the variables measured. Milk yield was increased by bST and tended to be greater for cooled cows. Fat percentages were increased by bST, and yields of fat, protein, and 3.5% fat-corrected milk, and the efficiency of conversion of dry matter to milk, whereas evaporative cooling increased body weights and protein yields, but decreased SNF and milk protein percentages. Rectal temperatures and respiration rates also were lower for cooled cows. And, bST increased nonesterified fatty acids in blood serum, suggesting that a part of the energy for increased milk production came from mobilization of body fat. Administration of bST effectively improved performance of cows under hot summer conditions whether evaporatively cooled or not.

Effects of the infusion of non-selective beta-, and selective beta1- or beta2-adrenergic agonists, on body fat mobilisation in underfed or overfed non-pregnant heifers.

The aim of this study was to analyse the effects of the intravenous infusion of a non-selective beta-agonist (beta-A) (isoproterenol, ISO), and selective beta1-A (dobutamine, D) or beta2-A (terbutaline, T) on body fat mobilisation in non-pregnant heifers, in a 2 x 2 crossover design with two treatments (underfeeding or overfeeding) and two periods. The effect of the duration of submission to each energy level on basal and ISO-induced fat mobilisation was also studied. ISO had a high and significant lipolytic effect whatever the energy level. Nevertheless, the response area of non-esterified fatty acids (NEFA) to ISO in underfed cows was 1.7 times greater than that in overfed cows. T had a slight but significant lipolytic effect on NEFA plasma response in the underfed group. D had no lipolytic effect. Basal and ISO-stimulated plasma NEFA levels were similar after 1 or 4 weeks of underfeeding.

Impact of amino acid nutrition during lactation on body nutrient mobilization and milk nutrient output in primiparous sows.

The impact of amino acid nutrition during lactation on body nutrient mobilization and milk nutrient output in primiparous sows was evaluated. Thirty-six sows, nursing litters of 13 pigs, were allocated daily 6 kg of a fortified corn-soybean meal diet containing a high (HP, 1.20% lysine) or low (LP, .34% lysine) protein content during a 23-d lactation. Dietary lysine concentration was achieved by altering the ratio of corn and soybean meal in the diet. The LP sows consumed less daily ME (14.2 vs 16.1 Mcal; P < .11) and daily lysine (16 vs 59 g; P < .01) than the HP sows. Daily litter weight gain was less (P < .01) for sows fed the LP vs HP diet, and the differences increased (P < . 01) as lactation progressed. The lower litter weight gain for the LP sows was reflective of the lower (P < .01) estimated milk DM, CP, and GE output of these sows. The LP sows lost more body weight (1.23 vs .21 kg/d; P < .01) during the initial 20 d of lactation. In the LP sows, 59% of the weight loss was protein, water, and ash, and 37% was fat. Weight loss in the HP sows was entirely accounted for by body fat mobilization, because these sows accrued body protein, water, and ash. Muscle myofibrillar breakdown rate was higher in LP sows than in HP sows (4.05 vs 2.80%/d; P < .01). On the basis of these data, dietary amino acid restriction during lactation increases maternal mobilization of proteinaceous tissue and reduces milk nutrient output. Maternal protein mobilization is maintained over the entire lactation even though milk output is decreased as lactation progresses.

Factors Affecting Body Tissue Mobilization in Early Lactation Dairy Cows. 2. Effect of Dietary Fat on Mobilization of Body Fat and Protein

Twenty-two multiparous Holstein cows were fed either a control diet or a control diet plus 3% added fat (dry matter basis) to determine the effect of added dietary fat on body tissue mobilization and milk production. Body composition measurements were taken using the D2O dilution technique at –2, 5, and 12 wk postpartum. Cows fed added fat produced 2.7 kg/d more milk than did those fed the control diet alone, but milk production, milk composition, and dry matter intake were not affected by diet. The maximum amount of body tissue loss occurred between –-2 and 5 wk postpartum when cows fed both diets mobilized 46kg of body fat and 12kg of body protein. Between 5 and 12 wk postpartum, only small changes in both body protein and body fat were observed. Even though cows fed added fat showed a tendency toward reduced body fat mobilization (66kg for cows fed the control diet vs. 37kg for cows fed the control diet plus added fat) and increased body protein mobilization (4.8kg for cows fed the control diet vs. 19.5kg for cows fed the control diet plus added fat), the differences were not significant. Apparent differences in fat mobilization between diets might have been due to initial body fat stores (159kg for cows fed the control diet vs. 126kg for cows fed the control diet plus added fat). Across diets, one unit of change in body condition score corresponded to about 55kg of empty body fat. Supplemental dietary fat did not reduce body tissue mobilization in early lactation.

肥育豚における静脈内へのエピネフリンの単回負荷による体脂肪動員の評価

Plasma free fatty acids (FFA) response to single intravenous administrations of epinephrine was investigated in growing-finishing pigs. Four gilts weighing about 65kg were fitted with a jugular catheter a week before the first epinephrine administration trial. Five doses, 0.1, 0.2, 0.4, 0.8, and 1.6μg/kg body weight (μg/kg BW), of epinephrine were intravenously administered through the catheter. Each pig was administered one dose each day, and dose levels were randomly allocated to each animal. Blood samples were drawn through the catheters at -30, -15, 0, 5, 10, 15, 20, 30, 40, 50, 60, 90, and 120 minutes after the epinephrine administration. Area under curve (AUC) of FFA was significantly increased by the epinephrine administrations (P<0.05). The estimated dose producing half-maximal response (ED50) and maximal responsiveness (Rmax) for the AUC of FFA were 0.311±0.113μg/kg BW and 573±167 (μEq/l)•min, respectively. From these results, it seems that in vivo mobilization of body fat in growing-finishing pigs can be estimated by single intravenous administrations of epinephrine.