Feeding Situation Research Articles

Major Advances in Nutrition: Impact on Milk Composition

A number of major scientific advances have been realized in the last 25 yr in determining the opportunities and limitations of altering milk composition through nutritional manipulation. Because of the greater sensitivity of milk fat to dietary manipulation than either protein or lactose, nutritional control of milk fat content and fatty acid composition received a great deal of attention. New information emerged linking ruminal production of trans fatty acid isomers with milk fat depression. As a result, research on fatty acid biohydrogenation intensified yielding new insight on the origin of specific trans fatty acid isomers originating from ruminal biohydrogenation and how these isomers were modified by the action of mammary enzymes. The discovery of conjugated linoleic acid (CLA) as a potent anticarcinogen also led to extensive work on enhancing its concentration in milk through nutritional manipulation and discovering the physiological effects of specific CLA isomers. New protected fats were developed in recent years that were designed to resist biohydrogenation and enhance the concentration of unsaturated fatty acids in milk. The nutritional factors receiving the most attention during the last 25 yr for their influence on milk protein content were forage-to-concentrate ratio, the amount and source of dietary protein, and the amount and source of dietary fat. New insights were tested on modes of action whereby fat supplements caused a decline in protein concentration. Changes in milk lactose concentration occur only in extreme and unusual feeding situations, but the basic biology of lactose synthesis and regulation are still being explored using modern molecular techniques. This paper highlights the major advances in controlling milk composition by dietary manipulation and how it influences the entire animal system from practical feeding studies to basic cellular work on mammary tissue metabolism.

Effect of cereal-based concentrates on productivity of Holstein–Friesian cows grazing short-rotation ryegrass (Lolium multiflorum) or kikuyu (Pennesitum clandestinum) pastures

Abstract In this study, the effect of increasing the proportion of concentrate in the diet, on efficiency of feed utilisation, was determined when Holstein–Friesian cows grazed short-rotation ryegrass (Lolium multiflorum) or kikuyu (Pennisetum clandestinum) pastures. The concentrates were energy-dense dairy pellets fed twice-a-day at milking and the roughage component was lucerne hay and the pasture. When cows grazed ryegrass, there was no effect on animal performance as the proportion of concentrate in the diet increased from 0.23 to 0.35 (4.75 to 7.50 kg concentrate/cow/day). The substitution rate of concentrates for pasture for the first 1.57 kg concentrate/cow/day fed was 0.58 but rose to 1.18 for the next 1.28 kg concentrate/cow/day. When cows grazed kikuyu, there was also no effect of increasing the proportion of concentrate in the diet on total dry matter intake (DMI) or milk production. However, there was a substantial increase in the in vivo digestibility of whole diet, pasture and acid detergent fibre (ADF) was observed when the proportion of concentrate in the diet increased from 0.08 to 0.25. However, there was a marked decline in pasture digestibility (72% to 64%), and more so in ADF digestibility (61.3% to 48.4%), as the proportion of concentrate in the diet increased further to 0.29 (5.52 kg/cow/day). The intake of kikuyu, when determined by difference between pre- and post-grazing pasture mass, was substantially underestimated compared to the use of the n-alkane technique, and this discrepancy increased as the pasture on offer increased. On both pasture types, the neutral detergent fibre intake, as a % of bodyweight varying from 1.6% to 2.2% for kikuyu and 1.5% to 1.6% for ryegrass was far above the values claimed of 1.2% to restrict intake. The results of this study highlight the limits to the amount of concentrate that can be fed on a typical Australian dairy farm where concentrates can only be fed twice-a-day at milking. The results also provide a more appropriate benchmark for fibre limitation in the ration when cows graze pasture, particularly poorer quality tropical grasses, and this value is well above that found in more intense feeding situations.

Transfer from "edible" categorization training to feeding behavior in pigeons (Columba livia)1

: We investigated a transfer from an operant experimental situation to a feeding situation in pigeons using real objects as stimuli. Four pigeons were trained in an operant box to categorize familiar edible items as positives and inedible items as negatives with a go/no-go procedure. Next, two pairs of unfamiliar edible items were added as stimuli. One of the paired stimuli was arbitrarily assigned as positive and the other as negative. We tested the subjects in their home cages to see whether they would feed on the items they were trained to categorize as positives. In three of the six cases in which categorization training was successful, they continued to peck the positive items. This result suggests that the pigeons transfer what they learned in the operant training situation to the feeding situation.

Mothers’ experiences of feeding situations – an interview study

The aim of the study was to describe parents' experiences concerning feeding situations and their contact with the nurse at the Child Health Service (CHS). Some of the most important tasks for the nurse at the CHS are to monitor growth, detect feeding difficulties and give advice concerning food intake and feeding practices. Eighteen mothers differing in age, education, ethnicity and number of children and recruited from different CHS were interviewed. The narratives were transcribed verbatim and analysed by content analysis at manifest and latent levels. All mothers' described that food and feeding were essential parts of their lives requiring a great deal of time and involvement. Two major categories of mothers' attitudes in feeding situations were identified - a flexible attitude and a controlling attitude. Mothers with a flexible attitude were sensitive to the child's signals and responded to them in order to obtain good communication. Mothers who expressed a need for control established rules and routines regarding the feeding situations. Mothers with a controlling attitude expressed receiving inadequate support from the nurse at the CHS. This study shows that some mothers experience inadequate support from the nurse at the CHS. Knowledge about mothers' experiences of feeding situations and their different attitudes towards the child during feeding might improve the CHS nurses' knowledge and help them understand and more adequately support mothers who experience feeding difficulties.

Perceived and observed parenting behavior in American and Italian first-time mothers across the first 3 months

This short-term longitudinal study investigated cross-cultural universality (similarities) and cultural specificity (differences) in American and Italian first-time mothers’ perceived parenting efficacy and observed parenting behavior in early infancy. Thirty-two mother–infant dyads from the United States ( n = 16) and Italy ( n = 16) participated in this study at 1 and 3 months across the first developmental transition. Maternal self-efficacy in parenting was assessed by self-reports. Mothers’ parenting behavior was observed and videotaped in a feeding situation. Both micro- (15-s time sampling) and macro-analytic (global ratings) strategies were employed to measure maternal and infant behaviors. Results revealed both cross-cultural similarities and differences in American and Italian mothers’ perceived parenting efficacy and observed parenting behavior. Both American and Italian mothers perceived themselves as becoming more efficacious in their parental role from 1 to 3 months and demonstrated significant stability in their individual differences over time. Compared to American mothers, Italian mothers displayed greater social/affective and handling/holding behavior. Whereas American mothers showed more synchronous responses to their infants when they were resting, Italian mothers spent significantly more time in synchronous dyadic social exchanges with their infants. The findings are discussed from the perspective of cultural organization of parenting, which suggests that parents structure everyday activity for their infants in accordance with cultural values and expectations.

Chronic food restriction and reduced dietary fat: Risk factors for bouts of overeating

The purpose of this study was to determine the effect of chronic food restriction and reduced dietary fat on feeding behavior and body weight. Young female rats were fed ad lib or food restricted on a low-fat (LF) or a fat-free (FF) diet for 4 weeks. Rats then received 24-h free access to 2 diets, the maintenance diet (LF or FF) plus a novel high-fat (HF) diet (24-h intake test). After the test, all the rats were allowed chronic free access to the HF diet until body weight was stable. During the 24-h test, the restricted groups ate significantly more calories than the ad lib groups, and the FF-restricted rats ate significantly more total food, carbohydrate and protein than the LF-restricted rats; there were no differences between the two ad lib groups. During chronic free access to the HF diet, the formerly restricted rats achieved and defended lower body weights than the formerly non-restricted rats. Throughout the experiment, the ad lib groups had more body fat than the restricted groups independent of the dietary subgroup. Hence, a history of chronic food restriction predisposes to consuming more food in acute feeding situations, particularly when dietary fat is reduced, and lowers the level of body weight maintained and defended. Chronic food restriction accompanied by reduced dietary fat may increase risk for bouts of overeating.

Development of co-feeding behavior in young wild Japanese macaques ( Macaca fuscata)

This study describes the developmental course of the social context of feeding behavior in infants and yearlings of Japanese macaques in a provisioned free-ranging troop. Results of this longitudinal study revealed that infants and yearlings exhibited synchronous feeding behavior in the majority of cases in which they had feeding neighbors within 1 m. They consistently showed feeding behavior more often when their closest neighbor fed than when they did not. In feeding situations, infants tended mainly to be in close proximity with their mothers in the early stages of life and, later, also with peers. The results imply that potential opportunities for the social transmission of food selection habits are available for young Japanese macaques in the wild.

Interactive skills of infants with their high-risk mothers

In this pilot study, the interactive skills of infants with their high-risk, substance-dependent mothers were explored in residential treatment from pregnancy until the infant was 6 months of age. Fourteen mother–infant pairs were videotaped in feeding and free play situations at 6 months after birth. A comparison, low-risk group consisted of 12 ordinary Finnish mother–infant pairs with minimal clinical risks. The findings show significantly higher levels of dyadic interactive deficiencies among the high-risk mother–infant pairs compared to the low-risk pairs, displayed especially in the feeding situation as lack of mutuality and flat, empty, constricted affective tone of interaction. Also, more interactive deficiencies were found among the high-risk infants compared to the low-risk infants, but the differences were not significant. In this study, this finding might reflect the reduced amount of somatic complications and the benefits of treatment, the impacts of which were not explored. The differences between the high- and low-risk infants were displayed as more withdrawal, depressed mood and avoiding behavior and as less alertness and attentional abilities, robustness and focus on parent's emotional state among the high-risk group.

Assessment of early mother–child relation in infants with oesophageal atresia

Fifteen one-year old infants with oesophageal atresia and their parents were used to demonstrate how the Parent–Child Early Relational Assessment (PCERA) can be used to explore the mother–child interaction in a clinical sample of children. The infants and their mothers were videotaped for 5-min episodes during feeding and free play, and the quality of the mother–infant interactions was assessed by PCERA. The results showed areas of strength regarding most of the maternal, infant and dyadic components. There was concern about maternal positive physical contact, maternal quality of verbalizations to or about the child, maternal social initiative, infant's communicative competence and infant's visual contact with mother. This concern of social proximity between infants and their mothers was most prominent in the feeding situation. The present study indicates that oesophageal atresia in infants may constitute stressors impinging on the parent–infant relationship. PCERA was found to be an adequate assessment tool with acceptable reliability to evaluate the mother–infant interaction.

Active and passive social support in families of greylag geese (Anser anser).

In general, support by social allies may reduce stress, increase success in agonistic encounters and ease access to resources. Social support was mainly known from mammals, particularly primates, and has been studied in birds only recently. Basically two types are known: (i) 'active social support', which describes the participation of a social ally in agonistic encounters, and (ii) 'passive social support' in which the mere presence of a social ally reduces behavioural and physiological stress responses. In greylag geese (Anser anser) offspring stay with their parents for an entire year or even longer and therefore are a candidate avian model to study support by social allies. We investigated the effects of active and passive social support in ten families (ten males, ten females, 33 juveniles) in a free-roaming, semi-tame flock of greylag geese. Focal individuals were observed during three time periods: (i) re-establishment of the flock in the fall, (ii) stable winter flock, and (iii) disintegration of the flock and break-up of family bonds. We recorded all agonistic interactions of the members of one focal family during morning feedings for two consecutive days: a control day, in which food was distributed widely, and a social density stress situation, in which the same amount of food was spread over a much smaller area. In addition, we collected faeces of all individuals within this family for three hours from the beginning of the feeding situation for determining excreted corticosterone immuno-reactive metabolites by enzyme immuno assay. We found that the small families, i.e. pairs with one or two accompanying young, were involved in more agonistic interactions, mainly through the lack of active social support, as compared to large families in the same situation. Members of greylag goose families lost agonistic encounters significantly less often when actively supported. In addition, the excretion of corticosterone metabolites was significantly decreased in large families during a social density stress situation, probably as an effect of passive social support. Via such a socially induced decrease in hormonal stress response during challenging situations, an individual's long term energy management may benefit.

Psychosocial Care of Severely Malnourished Children

The psychosocial intervention program for malnourished children at Hôpital Albert Schweitzer has evolved over several years and now consists of daily interventions including music on the unit, cooking and feeding instruction, exercise sessions, supervised play sessions, daily massage of children by their parents, toy making, and singing and dancing. The interventions are supervised by Haitian personnel and have been developed according to what is interesting and stimulating for Haitian parents and their children. These interventions appear to have greatly improved the moods of the parents and their children. They seem happier. There is more interaction between the parents and the children throughout the day, including touching, playing, and talking. The feeding situation has improved. Parents feed their children; there is more socializing and eye contact during meals. Our experience supports the concept that the rehabilitation of the malnourished child is facilitated by interventions that restore a positive parent-child relationship. These interventions should be tailored to the local culture. Future studies could evaluate the effect of such interventions on the parent-child interaction at the beginning and end of the hospitalization, as well as on parameters such as mortality, rate of weight gain, length of stay, and readmission rates.

THE EFFECT OF FLUID DENSITY AND VOLUME ON THE ACCURACY OF TEST WEIGHING IN A SIMULATED ORAL FEEDING SITUATION

For preterm infants and infants who have difficulty with oral feeding, excessive drooling during oral feedings can result in inaccurate assessment of intake. The drooled volume is typically estimated by visual and tactile assessment of the bib. Research, however, has demonstrated that visual assessment is inaccurate. The purpose of this study was to determine the accuracy of a scale that was used for the test weighing of milk that was drooled during a study of oral feeding for preterm infants. Additionally, the effect of weighing solutions with different densities on the accuracy of test weights was examined. Descriptive, comparative design. A simulated feeding situation was performed using 3 fluids (water, Enfamil(20), and Enfamil(24)) and 3 volume ranges (1 mL to 10 mL, 11 mL to 20 mL, and 21 mL to 30 mL). Data collection sessions were conducted for each of the 3 fluids using each range of volumes, for a total of 180 test weights. The research assistant performing the test weights was blinded to the preweight of the bib and the amount of fluid being applied to the bib. Differences between the actual volume applied to the bib and the volume estimated by the scale were very small, with 51% of the differences equaling 0 mL and 48% of the differences between -1 mL and 1 mL. There were significant differences in errors related to both the type of fluid (F = 25.7; df = 2; P < 0.001) and volume range (F = 12.7; df = 2; P < 0.001), as well as for the interaction between the 2 factors (F = 7.02; df = 4; P < 0.001). Water had significantly less mean error than either formula, and large volumes had significantly greater mean error than either small or medium volumes. Test weighing is an accurate method for measuring fluids of different densities and volumes in a simulation of drooling during oral feeding. The increased error with larger volumes of higher density solutions was not clinically significant. The study supports the need to consider both the accuracy of the scale and characteristics of the fluid when test weighing is used to measure volumes of fluids.

Two Solitudes: The Behaviour of Pigeons in Competitive Feeding

AbstractPrevious research showed that pigeons foraging for preferred grains of maize and less preferred grains of wheat respond to the presence of a competitor by becoming less choosy ( i.e. they more readily choose wheat). We extended this work by disentangling the presence of the competitor from the resource depletion associated with it. In Experiment 1, eight birds foraged for maize and wheat in a flight cage. They were tested both alone and with another bird in different foraging sessions. Two groups were formed and differed in how they were treated when the birds foraged in pairs: both birds had access to food (Both Eat) versus only one bird had access to food (Only One Eats) while the other was placed behind a transparent curtain. For the latter treatment, no effect of the mere presence of the other bird on choice was found. Pigeons were, however, less choosy in the presence of a real competitor that exploited the food. At the end of the experiment, the pigeons that had been tested in the 'Both Eat' treatment, were tested in the 'Only One Eats' treatment. They behaved as if foraging alone. Experiment 2 introduced a new condition in which one bird ate and the other was placed behind the curtain where it pecked at grain but could not eat it. Even though this other bird behaved as if it were a potential competitor, it had no effect on the forager in the pair. The only significant difference in choice proportions was between birds foraging in real competition ( i.e. where the other bird caused resource depletion) or not. In competitive feeding situations, pigeons react to what is most directly associated with the dwindling food conditions but are insensitive to the presence and to the pecking behaviour of the animal that creates them.

Comparative evaluation of the Molly, CNCPS, and LES rumen models

This study was conducted to evaluate and compare three rumen models with observed experimental data covering a wide range of feeding situations. Molly (MOL), developed by Baldwin in 1987, the Cornell Net Carbohydrate and Protein System (CNCPS), developed in 1992, and the model developed by Lescoat and Sauvant (LES) in 1995 were evaluated. These mechanistic models were compared on their ability to predict various rumen parameters and digestive characteristics. A database of 47 references (194 treatments) was built with animal characteristics, detailed rations and in vivo measurements on dairy cattle. A feedstuff library with all input parameters needed to evaluate the models was created for 73 feedstuff. Thus, the comparative simulations were based on identical and consistent feed inputs. Global regressions and general linear models within experiments were used to determine the ability of the models to predict global and within experiment variation. Evaluations involved four parameters: coefficient of determination, residual standard deviation, slope of the regression and mean deviation to the bisector ( Y= X). Results underlined the fairly good capacity of the model of Lescoat and Sauvant to predict starch digestion in the rumen, with a residual standard deviation of 0.06 kg/kg starch and slope of 0.70. The duodenal flow of microbial N was best predicted by the CNCPS with a residual standard deviation of 28.6 g/day and slope of 0.91. Rumen pH was best predicted by LES with a residual standard deviation of 0.10 and slope of 0.90. Alternatively, the models did not accurately predict fiber digestion in the rumen or volatile fatty acids concentrations. The study demonstrates the strengths and weaknesses of the models. Future improvements of rumen modeling can be considered by pooling the advantages of each model.

Social behaviour of dogs encountering AIBO, an animal-like robot in a neutral and in a feeding situation.

The use of animal-like autonomous robots might offer new possibilities in the study of animal interactions, if the subject recognises it as a social partner. In this paper we investigate whether AIBO, a dog-like robot of the Sony Corp. can be used for this purpose. Twenty-four adult and sixteen 4-5 months old pet dogs were tested in two situations where subjects encountered one of four different test-partners: (1) a remote controlled car; (2) an AIBO robot; (3) AIBO with a puppy-scented furry cover; and (4) a 2-month-old puppy. In the neutral situation the dog could interact freely with one of the partners for 1 min in a closed arena in the presence of its owner. In the feeding situation the encounters were started while the dog was eating food. Our results show that age and context influence the social behaviour of dogs. Further, we have found that although both age groups differentiated the living and non-living test-partners for some extent, the furry AIBO evoked significantly increased responses in comparison to the car. These experiments show the first steps towards the application of robots in behavioural studies, notwithstanding that at present AIBO's limited ability to move constrains its effectiveness as social partner for dogs.

Some Evolutionary Aspects of the Food-Procuring Group Behavior in Phylogenesis of Primates

The peculiarities were studied of the intragroup competitive and cooperative behavior of primates differing by the level of phylogenetic development, beginning from low-organized species of the higher primates to high-organized anthropoid monkeys (Callithrix jacchus, Cebus apella, Macaca mulatta, Papio hamaofrijas, Pan troglodytes). It has been shown that in all monkeys, under conditions of competitive feeding situation, there were changes of the complex behavioral forms observed at individual learning. Under conditions of the activity in pairs, the females of platyrrhine (New World) and lower narrow-nose (Old World) monkeys lost the possibility to realize the skill and food needs, so the programmed tasks were solved predominantly by the males. In chimpanzees, the change of indices of instrumental activity involved to the equal degree the male and female, and solution of the alternation task was higher in individual experiments. The age differences were revealed in the competitive behavior of chimpanzees in group. The realization of formed skills depended on the complex of factors including the requirements dominating in the given situation and the age and typological peculiarities, as well as the social rank of each monkey in the community. In rhesus macaques the capability for cooperative interaction was revealed under conditions of complex operant activity.

Do Chimpanzees Know What Each Other See? A Closer Look

Hare et al. (2000) reported that when placed into competitive feeding situations chimpanzees exhibit evidence of reasoning about what each other can see. Subjects were reported to select food items that were hidden behind barriers and therefore were not visible to a rival chimpanzee. We report eight experiments that attempted to replicate these findings and test alternative interpretations of them. Although we robustly replicated the finding that subjects obtained more hidden than visible food items, we consistently did not replicate the more relevant result of subjects' food choice. Further studies revealed that even those subjects who showed a tendency to approach the hidden food first did not differentiate between barriers which did and did not obscure the rival’s view. Overall, the results support the idea that although chimpanzees may use a variety of competitive strategies in such tests, no predictive power is added by postulating that they are reasoning about what each other can or cannot see.

Neophobia affects choice of food-item size in group-foraging common ravens ( Corvus corax )

Individuals foraging in groups should develop behavioural tactics to optimise their gain. In novel feeding situations, predation risk and pressure of kleptoparasites may be particularly high and hence may constrain optimal foraging. To create a novel feeding situation, we offered common ravens (Corvus corax) equal numbers of either small (40 g) or large (160 g) pieces of meat on successive days, always in combination with the same novel object. During the first weeks, when ravens were still neophobic, small pieces were taken in larger numbers than large pieces. Intraspecific kleptoparasitism was more likely to occur when ravens carried large food items. It seems that initiating foragers were mainly innovative subdominants. Preference for small items might have decreased with increasing habituation because more dominants were then feeding directly at the source and hence were less likely to resort to kleptoparasitism as an alternative foraging tactic.

Family-based interventions for the treatment of childhood obesity

Family-based interventions for the treatment of childhood obesity

Ghrelin, Macronutrient Intake and Dietary Preferences in Long–Evans Rats

Ghrelin is a recently discovered peptide that is primarily produced by the stomach. As a ligand of the growth hormone (GH) secretagogue (GHS) receptor, it stimulates GH secretion but it also stimulates feeding and has adipogenic effects in rodents. Although its circulating levels are modulated by fasting and refeeding, its relationship with diet composition is not known. In the present paper, we measured plasma ghrelin as well as two important hormones (leptin and insulin) in Long–Evans rats placed in two different feeding situations, e.g., either with imposed diets or with food choice. In the first case, the rats were fed unbalanced diets (either high-carbohydrate (HC) or high-fat (HF) diets) for 14 weeks, whereas in the second situation, they had the choice between these 2 diets for 2 weeks and were selected for their fat or carbohydrate preference. The intake of the HF diet for 14 weeks was associated with lower levels of ghrelin (−30% vs control diet; P < 0.01). These levels increased when the percentage of carbohydrate in the diet increased (+26 to +42% vs control diet; P < 0.01 or less). Ghrelin was inversely correlated with plasma leptin (r = −0.55; P < 0.003) and blood glucose (r = −0.58; P < 0.001) as well as with body weight (r = −0.63; P < 0.0001) and body fat content estimated by the sampling of specific fat pads (r = −0.62; P < 0.0001). In the food choice experiment, fat-preferring rats had plasma ghrelin levels lower than the carbohydrate-preferring rats (−33%; P < 0.0002). Ghrelin secretion was therefore very sensitive to the diet composition. Its down-regulation by fat ingestion might serve as a counterregulatory mechanism to limit the development of dietary-induced adiposity. Ghrelin may signal when a high calorie diet is ingested.