Effects Of Underfeeding Research Articles

Effects of underfeeding and oral vancomycin on gut microbiome and nutrient absorption in humans.

Direct evidence in humans for the impact of the microbiome on nutrient absorption is lacking. We conducted an extended inpatient study using two interventions that we hypothesized would alter the gut microbiome and nutrient absorption. In each, stool calorie loss, a direct proxy of nutrient absorption, was measured. The first phase was a randomized cross-over dietary intervention in which all participants underwent in random order 3 d of over- and underfeeding. The second was a randomized, double-blind, placebo-controlled pharmacologic intervention using oral vancomycin or matching placebo (NCT02037295). Twenty-seven volunteers (17 men and 10 women, age 35.1 ± 7.3, BMI 32.3 ± 8.0), who were healthy other than having impaired glucose tolerance and obesity, were enrolled and 25 completed the entire trial. The primary endpoints were the effects of dietary and pharmacological intervention on stool calorie loss. We hypothesized that stool calories expressed as percentage of caloric intake would increase with underfeeding compared with overfeeding and increase during oral vancomycin treatment. Both primary endpoints were met. Greater stool calorie loss was observed during underfeeding relative to overfeeding and during vancomycin treatment compared with placebo. Key secondary endpoints were to evaluate the changes in gut microbial community structure as evidenced by amplicon sequencing and metagenomics. We observed only a modest perturbation of gut microbial community structure with under- versus overfeeding but a more widespread change in community structure with reduced diversity with oral vancomycin. Increase in Akkermansia muciniphila was common to both interventions that resulted in greater stool calorie loss. These results indicate that nutrient absorption is sensitive to environmental perturbations and support the translational relevance of preclinical models demonstrating a possible causal role for the gut microbiome in dietary energy harvest.

Expression of key lipid metabolism genes in adipose tissue is not altered by once-daily milking during a feed restriction of grazing dairy cows

The objective of this study was to investigate the effect of reduced milking frequency, at 2 feeding levels, on gene expression in adipose tissue of grazing dairy cows during early lactation. Multiparous Holstein-Friesian and Holstein-Friesian × Jersey cows (n=120) were grazed on pasture and milked twice daily (2×) from calving to 34±6d in milk (mean ± standard deviation). Cows were then allocated to 1 of 4 treatments in a 2×2 factorial arrangement. Treatments consisted of 2 milking frequencies (2× or once daily; 1×) and 2 feeding levels for 3wk: adequately fed (AF), consuming 14.3kg of dry matter/cow per day, or underfed (UF), consuming 8.3kg of dry matter/cow per day. After the treatment period, all cows were fed to target grazing residuals ≥1,600kg of DM/cow per day and milked 2× for 20wk. Adipose tissue was collected from 12 cows per treatment by subcutaneous biopsy at −1, 3, and 5wk relative to treatment start, RNA was extracted, and transcript abundance of genes involved in lipid metabolism was quantified using a linear mixed model. At the end of the 3-wk treatment period, transcript abundance of genes involved in fatty acid (FA) uptake into adipose tissue (LPL), FA synthesis [FA synthase (FASN) and stearoyl-coenzyme A desaturase (SCD)], FA oxidation [acyl-coenzyme A synthetase long-chain family member 1 (ACSL1) and carnitine palmitoyltransferase 2 (CPT2)], glyceroneogenesis [glycerol-3-phosphate dehydrogenase 1 (GPD1) and pyruvate carboxylase (PC)], and triacylglyceride synthesis [diacylglycerol O-acyltransferase 2 (DGAT2)] were greater in AF1× cows compared with all other treatments. However, when cows were underfed, no effects of milking frequency were observed on transcript abundance of genes involved in adipose lipid metabolism. Despite increases in plasma NEFA concentrations in UF cows, no effects of underfeeding were observed on the transcription of lipolytic genes. At 5wk, after cows were returned to 2× milking and standard feed allowance, transcript abundances of genes involved in FA synthesis [acetyl-coenzyme A carboxylase α (ACACA) and SCD)] were increased in cows previously UF. Expression of ACSL1 was decreased in UF1× cows relative to UF2× cows and CPT2 expression was greater in AF1× cows compared with AF2× cows. In conclusion, after 3wk of reduced milking frequency during a feed restriction, transcription of genes involved in lipid metabolism in adipose tissue were not altered, possibly due to the reduced milk production in these animals. However, 3wk of 1× milking in AF cows increased transcription of genes involved in FA synthesis, oxidation, and triacylglyceride synthesis.

Nutrition classics. The American Journal of Cancer, Volume XXXVIII, March, 1940: The initiation and growth of tumors. Introduction. I. Effects of underfeeding. By Albert Tannenbaum.

Nutrition classics. The American Journal of Cancer, Volume XXXVIII, March, 1940: The initiation and growth of tumors. Introduction. I. Effects of underfeeding. By Albert Tannenbaum.

Effects of underfeeding during the weaning period on growth, metabolism, and hormonal adjustments in the piglet

Effects of underfeeding during the weaning period on growth, metabolism, and hormonal adjustments in the piglet

Effects of underfeeding and refeeding on offals weight in the Barbary ewes

The influence of long-term (161 days) underfeeding and refeeding (154 days) on the weight of offal components, and digestive content, was studied in 26 adult Barbary ewes. Effects on the protein and mineral content of offals were also measured. Animals were split in three groups: one was fed hay at maintenance level (M), another also received vetch–oat hay to cover 0.2 of maintenance energy requirements (L), and the third one was fed at 0.2 of maintenance requirements during 161 days, then refed at 1.3 times of energy requirements with a diet of hay and barley grain (LH) during 154 days. Underfed animals body weight (BW) at slaughter was 31 kg. Animals of groups M and LH were slaughtered at similar BW (50 kg). Underfeeding reduced empty BW by 38% and the weight of most metabolically active organs: skin (40%), blood (31%), rumen (34%) and liver (19%), but not others (small intestine). Total offals weight was reduced by 27%. Overfeeding of previously underfed animals (LH) induced a significant increase in liver weight in comparison to M group (18%), owing to a higher nutrient supply. The amount of protein in offals and their fat-free weight were decreased by underfeeding, whereas the amount of minerals was significantly modified only in components rich in bone. These results showed that splanchnic organ mass decreases with underfeeding which leads to energy requirements decrease and contributes towards resistance of Barbary ewes to harsh food conditions.

Effects of underfeeding and refeeding on weight and cellularity of splanchnic organs in ewes.

We assessed the effects of a long and severe period of underfeeding, followed by a rapid refeeding with a high-concentrate diet, on weight, protein mass, and cellularity of the splanchnic organs in adult ewes. Twenty-four ewes, allocated to four groups of six, were fed a forage diet (50% regrowth of natural grassland hay and 50% wheat straw) either at maintenance (groups M and MO) or at 40% maintenance (groups U and UO) for 78 d. Groups M and U were then slaughtered, and groups MO and UO were subsequently overfed a high-concentrate diet (52% hay, 20% barley, 16% rapeseed meal, 4% fish meal, and 8% Megalac) at 236% maintenance for 26 d before being slaughtered. During the experiment, feed was adjusted to maintain feed supply at a constant percentage of animal requirements. After slaughter, fresh weight, dry weight, and protein mass of the reticulorumen, omasum, abomasum, small intestine, large intestine, and liver were measured. Cellularity was assessed from nucleic acids and protein contents for both ruminal mucosa and muscular-serosa layers, jejunum, and liver. The concentrations of ubiquitin and cathepsin D mRNA were measured in ruminal mucosa and muscular-serosa layers and in jejunum. Underfeeding decreased protein mass of splanchnic organs, especially in liver (-29%) and reticulorumen (-39%). Refeeding previously underfed animals increased protein mass of liver (+102%) and small intestine (+59%). No carry-over effect of the previous level of intake (UO vs. MO) was observed on the protein mass of splanchnic tissues after 26 d of refeeding. Variations in liver mass were mainly due to hypertrophy, as determined by the protein:DNA ratio, whereas variations in small intestinal mass were mainly due to hyperplasia, as determined by the amount of DNA. By contrast, changes in rumen mass associated with increasing ME intake seemed to be related to hypertrophy in the muscular-serosal component and hyperplasia in the epithelial component. The concentrations of ubiquitin and cathepsin D mRNA in the rumen and jejunum were not modified by feeding level, demonstrating that the expression of these genes for proteolytic enzymes was unchanged under these conditions.

Effects of underfeeding during the second gestation of Holstein-Friesian heifers. 2. Residual effects on second lactation performance

Previous work has shown that dry period protein feeding can have important residual effects on the subsequent lactational performance in dairy cows (Moorbyet al., 1996), although the results have been variable. This variability may be due to an animals nutrient requirements during late lactation and its ability to compensate during the dry period for previously inadequate supplies. This experiment was designed to investigate the effects of heifer age and level of concentrate offered during the second half of the first lactation on the second lactation performance. The size of theLongissimus dorsiwas monitored as a marker of skeletal muscle use for lactation.Thirty-eight Holstein-Friesian heifers were treated as described by Dewhurstet al.(1997). Briefly, animals were divided into 4 treatment groups differing in age at first calving (2 or 3 years old) and level of concentrate feeding for the last 18-20 weeks of their first lactation (2 kg/d, ‘L’, or 7 kg/d, ‘H’; n=11, 11, 9 and 7 for treatments 2L, 2H, 3L and 3H respectively). Six weeks before predicted calving date, animals were dried off and offered a relatively low quality diet ofad libitumaccess to a grass silage:straw mix (40:60 on a DM basis), designed to offer them little chance to compensate for previous differences in diet. After calving, animals were offered a diet ofad libitumaccess to grass silage plus 8 kg/d concentrate to day 120 of lactation, and 5 kg/d thereafter. Live weight was recorded weekly. After calving, milk yields were recorded daily, and milk samples taken weekly, to week 20 of lactation.

Effects of underfeeding during the second gestation of Holstein-Friesian heifers. 1. Direct effect on lactation performance over the final 5 months of lactation

Manipulation of energy- and protein supply during the dry period can affect milk production and composition in the next lactation (Moorby et al, 1996). These studies also demonstrated considerable between-animal variation in responses which may relate to previous nutritional history. This problem was addressed in the current experiment by (i) developing enhanced assessments of animal condition; and (ii) monitoring performance over successive lactations. The second half of the first lactation is a critical phase, particularly for young heifers, since they have to balance the competing demands of pregnancy, growth and a persistent lactation. Berg and Ekern (1993) showed that underfeeding heifers had a residual effect on milk production and composition in their second lactation.Forty-five Holstein Friesian heifers, which calved from September to December 1994, were selected for this work; 23 of the animals calved at approximately 3 years of age (‘3’), 22 at approximately 2 years of age (‘2’). Thirty-eight animals completed the experiment (to the end of their second lactation) and data from these animals are used here. The animals were maintained on a complete diet until April 1995 when they were offered 8 kg/day of concentrate with ad libitum grass silage for 3 weeks of covariance recording.

Effects of underfeeding and of fish meal supplementation on forage digestion in sheep

SUMMARYThe effects of severe food restriction and of protein supplementation on the apparent digestibility of a forage were studied on 12 wethers in 1992 at INRA, Theix. Ruminal digestion of the forage cell walls was studied in a second experiment carried out on four ewes fitted with rumen and duodenal cannulas, receiving the same diets as the wethers. The animals were fed on two different hay-based diets: hay only (58 or 25 g/kg BW0·75 per day) or hay supplemented with fish meal (48 or 20 g hay with 6·5 and 3·0 g fish meal respectively per kg BW0·75). The effects of fish meal supplementation on apparent digestibility of the hay cell walls were small, + 1·8 and + 2·3 units for neutral detergent fibre (NDF) and acid detergent fibre (ADF) respectively. In contrast, NDF and ADF digestibility was respectively 4·0 and 4·7 units higher at low than at high intake. Rumen fluid volume decreased by 2·4 1 with decreasing intake, while water concentration in rumen content increased slightly from 89·8 to 91·8%. The mean retention time of the hay particles in the foreguts increased concomitantly from 39·5 to 55·1 h. This was achieved by a higher retention time to a similar extent in both slow and fast compartments. The calculated in situ degradability of NDF and ADF increased respectively by 12·1 and 13·1 units with decreasing intake. This reflected the lower fractional outflow rate recorded at low intake. If a fractional outflow rate value of 4·1%/h (as measured in high intake diets) was applied to all dietary treatments, NDF and ADF in situ degradability would be greater at low than at high intake (31·7 v. 26·6% for NDF; 27·9 v. 22·1 % for ADF), indicating a higher microbial activity in restricted diets. Interactions between intake and fish meal supply were detected for in situ degradation parameters, indicating principally a reduction of the cell wall undegraded fraction in supplemented diets when intake declined. Ruminal fermentation was modified by the dietary treatments, the acetate: propionate ratio being higher at low intake. Fish meal increased concentrations of ammonia and of isoacids in rumen liquid. The relationship between apparent digestibility and in situ degradability of plant particles is discussed.

Effects of underfeeding and refeeding on GH and thyroid hormone secretion in young, middle-aged, and old rats

The effects of a 50% reduction in normal food intake for a period of 10 weeks were measured on secretion of growth hormone (GH), thyroxine (T 4), and triiodothyronine (T 3) in 5 1 2 −6 1 2 - month-old, and 17 1 2 −18 1 2- month-old male rats. In full-fed controls, GH, T 3, and T 4 were lower in the old and middle-aged than in the young rats. By the 10th week of underfeeding, GH, T 3, and T 4 were reduced in all age groups, but the decrease in T 3 and T 4 in the middle-aged and old rats was greater than in the young rats. Pulses of GH ceased in all the underfed groups. Upon refeeding for 5 days, pulses of GH and levels of GH returned to full-fed control values in the young and middle-aged but not in the old rats. T 3 values in the young and middle-aged rats returned to full-fed control levels, but remained below control levels in the old rats. T[in4 values reached control levels in all age groups upon refeeding. The differences in the response to underfeeding and refeeding by the middle-aged and old rats as compared to the young rats may be due to their initially lower secretion of GH and thyroid hormones and to the age-related decrease in neuroendocrine function.

Effects of underfeeding and of starvation on thermoregulatory responses to cooling in women.

1. The effects of acute alterations in energy intake on the thermoregulatory responses to a cooling stimulus were studied in healthy, normal weight, young female subjects. On separate occasions, seven subjects were underfed for 7 days at 60 kJ day-1 kg-1 ideal body weight and six subjects were starved for 48 h. The cooling stimulus was provided by a coverall perfused with water at 16 degrees C. 2. After the application of the cooling stimulus, central body (auditory canal) temperature rose initially in both studies. After underfeeding, the magnitude of this rise in temperature was not significantly different from that seen in the normally fed state. After 48 h starvation, the rise in temperature on cooling was reduced from 0.30 (SEM 0.03) to 0.10 (0.04) degrees C (P less than 0.01). In two subjects in whom central body temperature had been maintained in the normally fed state, a fall occurred after starvation. 3. Underfeeding for 7 days did not affect thermogenesis or the degree of vasoconstriction in the forearm or hand in response to cooling. 4. After 48 h starvation, the thermogenic response to cooling was abolished and blood flow in the forearm remained higher than in the normally fed state. 5. In normal weight young females, thermoregulatory responses to a cooling stimulus were therefore substantially affected by 48 h starvation but not by 7 days underfeeding.

The effects of underfeeding during pregnancy and lactation on structure and chemistry of bovine liver and muscle

SummaryAn experiment was carried out to study the effects of underfeeding during late pregnancy and early lactation on the structure and chemistry of liver and muscle of dairy cows. Two groups of cattle were fed at 60 and 40% of estimated requirements for maintenance and pregnancy or lactation for 13 weeks before and 13 weeks after calving, and one group was fed at maintenance level only for the same period. A control group was fed at 100% of estimated requirements for the same period. All groups were subsequently fed at the control level for a further 24 weeks.Underfeeding resulted in significant changes in muscle and liver of dairy cows. In particular, there was a decrease in liver cell volume in the underfed groups and a persistence of post-parturient fat in the moderately underfed cows. Muscle fibre diameter was reduced and there was a loss of fast twitch oxidative glycolytic fibres in the underfed cows.

Influence of the thyroid gland on ovarian function in the aging rat.

The effects of underfeeding and manipulation of the thyroid axis on ovarian function were determined in young and old rats. The depressant effect of reduced food intake on ovarian cycling in young females was potentiated by chemical thyroidectomy, while young anestrous, underfed rats cycled when their diet was supplemented with thyroid extract. These observations iindicate that cycling aberrations in underfed rats may occur secondarily to an altered thyroid state. To determine if thyroid state influences ovarian function in old animals, constant estrous (CE) rats were underfed or chemically thyroidectomized. All underfed rats eventually cycled, while the response to chemical thyroidectomy alone, though still effective, was less dramatic. Realimented CE animals eventually returned to a pattern of constant vaginal cornification. Underfeeding had no effect on ovarian function in old recurrently pseudopregnant females however, these rats responded to thyroid treatment with renewed cycling. 4-6 (YC) 10-12 (PEP) month old females entered a persistent vaginal estrous condition when fed low doses of thyroid extract with their ad libitum diet. When the thyroid supplemented diet was discontinued, YC females resumed regular cycling, whereas the vaginal smear in 40% of the PEP rats remained cornified. Cycling could be restored in YC-thyroid induced CE rats by electrochemical stimulation of the medial preoptic area. These date suggest that senile deviations from normal cycling in the aging reproductive system may be affected by alterations in the thyroid state.

The Initiation and Growth of Tumors. Introduction. I. Effects of Underfeeding.

The tumor process, in the main, consists of initiation and growth. In these studies initiation implies the conversion of normal tissue to malignant tissue without consideration of intermediary phases, of which little is known. Since, for practical purposes, initiation and growth are readily differentiated, they have been studied separately. Great importance has been attached to the dissimilarity between normal and tumor tissue, such as rate of growth and tissue respiration (Warburg). The fact remains, however, that there is, in general, no striking difference in chemical composition, enzyme content, and metabolism between the normal and the tumor cell; both follow certain fundamental laws of growth. Much attention has been given to the experimental retardation and acceleration of tumor growth, in the expectation that such studies would bring to light the factors concerned in the initiation and propagation of neoplasms. At first transplantable tumors were used; but of late, particularly since cancerigenic chemicals have become readily available, the induced tumor has been widely used for such investigations. Much of the earlier work can be criticized because of the paucity of animals used in the experiments, and the inadequacies and indefiniteness of the diets. In fact, some authors report that their animals on experimental diets died within a few weeks.