The influence of oral lubrication on food intake: A proof-of-concept study

As overeating, overweight and obesity remain public health concerns, it is crucial to design satiety-enhancing foods that suppress appetite and lower snack intake. Existing research identifies oro-sensory targets to promote satiation and satiety, yet it remains unclear as to whether it is ‘chewing’ or ‘oral lubrication’ that might amplify satiation signals. In this study, techniques from experimental psychology, food material science and mechanical engineering have been combined to develop model foods to investigate the role of chewing and oral lubrication on food intake. Novel model gels, similar in pleasantness, were given as a preload then their effects on subjective appetite and intake of a salty snack were measured in a between-subjects design. Three mint flavoured hydrogels were engineered to vary in their texture (fracture stress) and lubrication (inverse of coefficient of friction), and a control group received mint tea. Results showed that snack intake was suppressed by 32% after eating the low chewing/high lubricating preload compared to the high chewing/low lubricating preload (p < 0.05). Hunger ratings decreased from t₁ to t₃ (p < 0.05), however differences between conditions were subtle and not significant. Thus, this proof-of-concept study demonstrates that manipulating oral lubrication is a promising new construct to reduce snack intake that merits future research in the oro-sensory satiety domain.     

How sweetness intensity and thickness of an oral nutritional supplement affects intake and satiety

Oral nutritional supplements (ONS) can be used to improve the nutritional status of malnourished patients, but their effectiveness depends on adequate intake. This is not always achieved due to the disliked flavour and satiating properties of ONS. The aim of this study was to investigate the effect of sweetness intensity and thickness on intake and sensory sequential profile of an ONS. It was hypothesized that lower sweetness intensity and thickness would decrease oro-sensory stimulation and satiety, improve the sensory profile, and thus, improve ONS intake.The effect of sweetness intensity and thickness on intake and satiety was investigated using a 2 × 2 design (low-high-sweetness and thin/thick). Participants (n = 36) consumed each ONS to satiation. Each ONS was identical in macronutrient and calorie content. Appetite and thirst were measured throughout the morning of the test. Additionally, an expert sensory panel (n = 11), performed a sensory sequential profile of each ONS.No effect of sweetness intensity was found. Results showed that 33% more of the thin, compared to thick, ONS was consumed, without affecting satiety. Furthermore, mouth-drying first increased, up to a consumption volume of 300 ml, and then decreased, independent of sweetness intensity and thickness.In conclusion, this study showed that an ONS with lower thickness increased intake in healthy adults, without affecting satiety. This implies that, for ONS, attention should not be solely focused on nutritional content. Instead, a sensory-nutrition approach is recommended that balances nutritional content with oro-sensory cues. This proof of concept should be further investigated with malnourished older adults.     

Effects of feed delivery time on feed intake, milk production, and blood metabolites of dairy cows

The objective of the study was to determine the effects of feed delivery time and its interactions with dietary concentrate inclusion and parity on milk production and on 24-h averages and patterns of feed intake and blood metabolites. Four multiparous and 4 primiparous lactating Holstein cows were used in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Experimental periods included 14 d of adaptation and 7 d of sampling. A higher concentrate diet with a forage:concentrate ratio (dry matter basis) of 38:62 or a lower-concentrate diet with a forage:concentrate ratio of 51:49 was delivered at either 0900 or 2100 h. During sampling periods, daily feed intakes, as well as feed intakes during 3-h intervals relative to feed delivery, were determined. During 2 nonconsecutive days of the sampling period, jugular blood was sampled every 2 h. Average temperature and relative humidity in the experimental facility were 20.4°C and 68.1%, and the maximum daily air temperature did not exceed 25°C. This data does not suggest that cows were heat-stressed. Changing feed delivery time from 0900 to 2100 h increased the amount of feed consumed within 3 h after feeding from 27 to 37% of total daily intake but did not affect daily dry matter intake. The cows fed at 2100 h had lower blood glucose at 2 h after feeding but greater blood lactate and β-hydroxybutyrate acid at 2 and 4 h after feeding than cows fed at 0900 h. These effects of feed delivery time on the 24-h patterns in blood metabolites may be caused by the greater feed intake during the 3 h after feed delivery of the cows fed at 2100 h. Daily averages of glucose, urea, lactate, and β-hydroxybutyrate acid and nonesterified fatty acids in peripheral blood were not affected by time of feeding. The change in feed delivery time did not affect milk yield and milk protein but increased milk fat percentage from 2.5 to 2.9% and milk fat yield from 0.98 to 1.20 kg/d in multiparous cows, without affecting milk fat in primiparous cows. The interactions between diet and time of feeding on daily feed intake, milk production, and blood metabolites were not significant. The effects of the time of feed delivery on the 24-h patterns in blood metabolites suggest that this time may affect peripheral nutrient availability. Results of this study suggest beneficial effects of feeding at 2100 h instead of at 0900 h on milk fat production of lactating cows, but parity appears to mediate this effect.     

Effects of milk replacer meal size on feed intake,growth performance,and blood metabolites and hormones of calves fed milk replacer with or without butyrate ad libitum: A cluster-analytic approach

This study intended to classify ad libitum–fed calves according to their milk replacer (MR) meal size using the K-means clustering approach. This study aimed to investigate the effects of MR meal size on feed intake, growth performance, and blood metabolic and hormones of ad libitum MR-fed calves. German Holstein calves (16 male and 16 female) were studied from birth until d 77 of age. All calves received first colostrum (2.5 kg) milked from their dams within 2 h after birth. Subsequent colostrum meals (subsequent 4 meals until 2.5 d of age; 2 meals/d) and MR (125 g of powder/L; 21.7% crude protein, 18.6% crude fat) were fed ad libitum by teat bucket until d 10 ± 2 of age. Afterward, calves were housed in group pens with automatic feeders for MR (maximum of 25 L/d) and concentrate from 10 ± 3 d of age. Half of the calves received MR supplemented with butyrate to improve growth performance. Milk intake was stepped down to 2 L/d from wk 9 to 10, and 2 L/d of MR were offered until the end of the study. On d 1, 2, 4, and 7, and then weekly until wk 11 of age, blood samples were collected for measurement of metabolites and hormones related to energy metabolism and growth. The K-means cluster analysis on the MR meal size data collected from the automatic feeder resulted in 3 clusters (n = 14, n = 12, and n = 6). Two clusters with a sufficient cluster size (n = 14 and n = 12) were included for further statistical analysis using repeated measures mixed-model ANOVA. In both clusters, butyrate supplementation was equally distributed and failed to affect a difference in MR meal size. Cluster 1 showed calves with higher MR meal size (HI; 2.2 ± 0.11 L/visit of MR) and cluster 2 with lower meal size (LO; 1.8 ± 0.07 L/visit of MR) supplemented MR without (HIB?; n = 6; LOB?, n = 7) or with 0.33% calcium-sodium butyrate (HIB+; n = 6; LOB+, n = 7). Dry matter intake of MR did not differ between HI and LO, but intakes of concentrate and total dry matter tended to be greater in HI than in LO and increased more distinctly in HI than in LO at the end of the study. The average daily gain (g/d) was greater in HI than in LO. Plasma concentrations of total protein (g/L), albumin (g/L), glucose (mmol/L), urea (mmol/L), insulin (µg/L), and glucagon (ng/L) were higher, and the concentrations of insulin-like growth factor I tended to be higher, in HI than in LO calves. Plasma β-hydroxybutyrate was higher in LO than in HI at d 63 and lower in calves fed MR with butyrate at d 77. In conclusion, clustering analysis discriminates 2 main groups of calves with different MR meal size and indicates an effect of MR meal size on solid feed intake, growth performance, and metabolic changes.     

Blood,breast milk and urine: potential biomarkers of exposure and estimated daily intake of ochratoxin A: a review

The purposes of this review are to study potential biomarkers of exposure for ochratoxin A (OTA) in biological fluids (blood, urine and breast milk) for the period 2005–14, calculate the estimated daily intake (EDI) of OTA by using database consumption for the Spanish population, and, finally, to correlate OTA levels detected in blood and EDI values calculated from food products. The values of OTA detected in potential biomarkers of exposure for blood, breast milk and urine ranged from 0.15 to 18.0, from 0.002 to 13.1, and from 0.013 to 0.2 ng ml^–1, respectively. The calculated EDI for OTA in plasma ranged from 0.15 to 26 ng kg^–1 bw day^–1, higher than that obtained in urine (0.017–0.4 ng kg^–1 bw day^–1). All these values are correlated with the range of EDI for OTA calculated from food products: 0.0001–25.2 ng kg^–1 bw day^–1.     

Restricting daily time at pasture at low and high pasture allowance: Effects on pasture intake and behavioral adaptation of lactating dairy cows

In pasture-based dairy systems, daily time at pasture is restricted during several periods of the year. The aim of this experiment was to evaluate the effect of restricting time at pasture on milk yield, pasture dry matter (DM) intake, and grazing behavior of dairy cows according to pasture allowance (PA), which partly defines pasture availability. The experiment was carried out in spring on strip-grazed perennial ryegrass pastures. The 6 treatments consisted of 3 durations of daily time at pasture [U: unrestricted day and night grazing (22 h at pasture); R9: 1 grazing session restricted to 9 h between the 2 milkings; R5: 2 grazing sessions of 2.75 h after each milking) compared at low and high PA (13 and 24 kg of DM/d per cow >5 cm, respectively). Eighteen mid-lactation Holstein dairy cows were used according to a 6 × 4 incomplete Latin square design replicated 3 times with four 14-d periods. Pasture DM intake was measured by the ytterbium-fecal index method and grazing behavior from portable devices. On average, restricting time at pasture from U to R (mean of R5 + R9) decreased pasture intake by 2.9 kg of DM, milk yield by 1.3 kg, and milk protein concentration by 0.11%, and increased milk fat concentration by 0.20%. Pasture intake and milk yield did not differ significantly between R9 and R5. The reduction of pasture intake and milk yield with decreasing time at pasture was greater at high compared with low PA. Grazing times were 536, 414, and 305 min, representing proportions of time spent grazing of 0.40, 0.77, and 0.93 for treatments U, R9, and R5, respectively. The reduction of grazing time with decreasing time at pasture was greater at high compared with low PA. Pasture intake rate greatly increased with decreasing time at pasture, but mainly on R5 (29.8, 31.6, and 42.1 g of DM/min for U, R9, and R5, respectively). The effect of time at pasture on pasture intake rate was unaffected by PA. In conclusion, the effect of restriction of time at pasture on pasture intake and milk yield becomes more marked as PA increases. Cows offered only 2 grazing sessions of 2.75 h after each milking maximized pasture intake rate and consumed pasture as much as in one 9-h grazing session.     

Effects of overstocking at the feedbunk on the growth performance and sorting characteristics of a forage-based diet offered for ad libitum intake to replacement Holstein dairy heifers

Various forms of overcrowding are common in heifer-rearing operations. Our objectives for this study were to evaluate the effects of overstocking at the feedbunk (100, 133, 160, or 200% of capacity) on the growth performance, feedbunk sorting behaviors, and hygiene of 128 gravid Holstein heifers (475 ± 55.3 kg) consuming an alfalfa haylage and corn silage diet diluted with processed wheat straw at an inclusion rate of 25.2% (DM basis). In this study, heifers were overstocked only at the feedbunk, and not with respect to available freestalls or pen area. Heifers were blocked by weight, and subsequently assigned to 1 of 16 identical research pens. A total mixed ration was distributed at 1000 h daily for 91 d via a drive-through feed alley, with heifers allowed access to the feedbunk through head-locking feeding gates. Mean weights for the 4 blocks (32 heifers/block) were 406 ± 14.9, 453 ± 15.3, 493 ± 17.6, and 548 ± 21.9 kg. Generally, nutrient intakes were not affected by stocking rate at the feedbunk; mean intakes of dry matter, neutral detergent fiber, and total digestible nutrients across all feedbunk stocking rates were 10.63, 5.19, and 6.29 kg/d, respectively. Overall, the effects of competition at the feedbunk on heifer growth performance were minor, with a collective average daily gain of 1.02 kg/d across all treatments. Only trends for linear increases in total weight gain and BCS were observed with overstocking at the feedbunk. Collectively, overstocked rates also exhibited a trend for better feed-to-gain ratio than pens stocked at 100% of feedbunk capacity (10.3 vs. 11.0 kg:kg). We observed solid evidence that heifers collectively sorted against large (>19 mm) particles, and also exhibited preference for short (>1.18 and <8 mm) and fine (<1.18 mm) feed particles; however, these responses were not affected by feedbunk stocking rate. Additionally, heifers sorted against neutral detergent fiber as the concentration of neutral detergent fiber remaining in the feedbunk increased during the 24-h period following feeding; conversely, they preferred crude protein, as indicated by a decreasing concentration of this nutrient over time. Heifer hygiene was not affected by competition at the feedbunk. Under the experimental conditions established for this trial, overstocking at the feedbunk did not affect heifer growth performance, but it should not be practiced blindly without attention to other critical components of animal welfare.     

The influence of oral phenotypic markers and fat perception on fat intake during a breakfast buffet and in a 4-day food record

The ability to discriminate among foods with different fat contents has been associated with preference for high-fat foods and total fat intake. Consequently, oral phenotypic markers that influence fat perception may influence food selection and fat intake. The aim of this study was to investigate how the fungiform papilla (FP) count on the tongue tip, 6-n-propylthiouracil (PROP) bitterness, saliva flow, the increase in salivary flow via oil stimulation and the ability to perceive fat influence fat intake and food selection. A total of 107 subjects (80 female, 27 male) completed a 4-day self-administered food record before they rated the fat contents of different milk–cream mixtures and a high-fat emulsion. Of these subjects, 103 (76 female, 27 male) participated in an ad libitum breakfast buffet that was offered at the university cafeteria. The results show that the perception of the fat content of cream with 30.0% fat was associated with energy intake from fat and discretionary fats over 4 days and during the breakfast buffet. Subjects with lower FP counts ate relatively more high fat milk and spreads and as a consequence more fat during the breakfast buffet than subjects with high FP counts. The increase in salivary flow via oil stimulation was positively correlated with the reported intakes of discretionary and total fat over 4 days. These results support the hypothesis that FP count and the intensity perception of supra-threshold differences in fat content might play an important role in the selection of high-fat foods and fat intake.     

Effects of two contrasting dietary fibres on starch digestion,short‐chain fatty acid production and transit time in rats

Dietary fibres may cause dietary starch to escape digestion in the small intestine and enter the large intestine. If this results from the dietary fibres reducing the gastrointestinal transit time, those dietary fibres that reduce this the most would be expected to cause the most starch to escape digestion. We tested in rats the relative abilities of two contrasting dietary fibres, apple pectin (a soluble dietary fibre) and wheat straw (an insoluble, lignified dietary fibre), to reduce the whole gut transit time and to cause dietary starch to escape digestion. We provided male Wistar rats with a control, modified AIN‐76™ diet containing 20% fat but no dietary fibre, and with this diet containing 10% dietary fibre; the dietary fibre replaced the equivalent weight of starch in the control diet. Both dietary fibres, but particularly wheat straw, reduced the transit time compared with the fibre‐free control diet. Pectin, but not wheat straw, resulted in substantial amounts of starch in the caecal contents. This effect may result from the pectin increasing the viscosity of the digesta or causing it to gel. Large amounts of short‐chain fatty acids were found only in the caeca of rats provided with pectin. © 2000 Society of Chemical Industry