The NEW Eukanuba Best of Class in Nutrition programme kicks off at the Eukanuba Nutrition Forum in Lisbon

Veterinary Research Communications -     

Seasonal variations in the diet and food selection of the Algerian hedgehog Atelerix algirus

The Algerian hedgehog Atelerix algirus is an insectivorous species. However, the exact composition of its natural diet remains largely undetermined, especially in relation to seasonal variations in food availability. From March to November, we simultaneously analysed the composition of 180 hedgehog faecal samples and food availability in the Soumman Valley, Algeria to assess food selection in this species. The faeces contained 196 different prey species, of which 92% belonged to the class Insecta. The highest prey species diversity was found in the Coleoptera order (100 species recorded) and the highest species occurrence was found in Hymenoptera (65% of the prey items, mainly represented by the harvester ant Messor barbarus, a crop-ravaging species). This study shows that the Algerian hedgehog is mainly a generalist species with a diet that is strongly linked to food availability. However, seasonal variations were observed in prey selection, and a notable shift in food preference was observed during autumn. The exact nature of these changes in feeding behaviour remains to be investigated, notably in relation to changes in energy requirements of this species before hibernation, in terms of quantity and/or quality.     

Effects of food deprivation and particle size of ground wheat on digestibility of food components in broilers fed on a pelleted diet

The first aim of the experiment was to study the effect of wheat (Triticum aestivum) particle size on the digestibility of starch in a pelleted diet given to broilers. The second aim was to study the consequences of food deprivation before the excreta collection period (from 21 to 24 d). Wheat from a strong hardness cultivar was incorporated at 546.1 g/kg in diets. The other main ingredients were soybean meal (353.5 g/kg) and rapeseed oil (55.0 g/kg). Diets were given as pellets. The experimental design was a 2 x 2 factorial design testing two particle sizes of wheat flour and two procedures of a balance experiment (with or without food deprivation). Birds given diet C (wheat coarse grinding before pelleting) had significantly greater gizzard weight than birds fed on diet F (wheat fine grinding before pelleting). Starch digestibility value was significantly increased when birds were fed on diet F. This effect was halved by food deprivation. No significant effect of grain particle size was observed for protein and lipid digestibility values. However, food deprivation decreased apparent protein digestibility, with an effect which was more pronounced for fine than for coarse grinding. AMEN of the diet was significantly improved by fine grinding of wheat and decreased by food deprivation. However, no significant differences in growth performance were induced by differences in wheat grinding. No significant effect of grinding was observed on the water excretion:feed intake ratio. No significant difference was observed for vent score between treatments. There was over-excretion of starch in the first hours of refeeding following food deprivation.     

Effects of probiotic bacteria in dogs with food responsive diarrhoea treated with an elimination diet

We evaluated whether a probiotic supplementation in dogs with food responsive diarrhoea (FRD) has beneficial effects on intestinal cytokine patterns and on microbiota. Twenty-one client-owned dogs with FRD were presented for clinically needed duodeno- and colonoscopy and were enrolled in a prospective placebo (PL)-controlled probiotic trial. Intestinal tissue samples and faeces were collected during endoscopy. Intestinal mRNA abundance of interleukin (IL)-5, -10, -12p40 and -13, tumour necrosis factor-alpha, transforming growth factor-beta1 and interferon (IFN)-gamma were analysed and numbers of Lactobacillus spp., Bifidobacterium spp., Enterococcus spp. and Enterobacteriaceae and supplemented probiotic bacteria were determined in faeces. The Canine Inflammatory Bowel Disease Activity Index, a scoring system comprising general attitude, appetite, faecal consistency, defecation frequency, and vomitus, decreased in all dogs (p < 0.0001). Duodenal IL-10 mRNA levels decreased (p = 0.1) and colonic IFN-gamma mRNA levels increased (p = 0.08) after probiotic treatment. Numbers of Enterobacteriaceae decreased in FRD dogs receiving probiotic cocktail (FRD(PC)) and FRD dogs fed PL (FRD(PL)) during treatment (p < 0.05), numbers of Lactobacillus spp. increased in FRD(PC after) when compared with FRD(PC before) (p < 0.1). One strain of PC was detected in five of eight FRD(PC) dogs after probiotic supplementation. In conclusion, all dogs clinically improved after treatment, but cytokine patterns were not associated with the clinical features irrespective of the dietary supplementation.     

Voluntary food intake variation in chickens on lysine-free diet is attributed to the plasma lysine concentration

1. Growing chickens decrease their voluntary food intake when they receive a diet deficient in a single essential amino acid. Our previous studies suggest that the decreased food intake was associated with some metabolic changes.

2. In order to reveal the involvement of plasma lysine fluctuations in the reduction of food intake, we examined whether maintaining the plasma lysine concentration in chickens on a lysine-free diet (the purified diet contained no lysine) restored the food intake to that of the control (lysine hydrochloride 11.9 g/kg) group.

3. Male egg-type chickens at 21 d of age were injected with lysine at doses of 0.1 g/ml one hour after presenting the lysine-free diet. This injection increased the plasma lysine concentration one hour later and kept it similar to that of the control group for the following 2 h. Chickens ate the lysine-free diet as much as the control diet when their plasma lysine concentration was kept at a similar level to the control group. Injection of saline or alanine (0.12 g, isonitrogenous to lysine 0.1 g) into the crop of chickens on the lysine-free diet did not bring about the variations of food intake and plasma lysine concentrations as observed in those with lysine.

4. These findings show that the food intake variation was attributed to the plasma lysine concentration in the chickens on the lysine-free diet.     

Effects of food intake,soaking time,enzyme and cornflour addition on the digestibility of the diet and performance of broilers given wet food

1. Four experiments were carried out to investigate the effects on growth, food conversion efficiency (FCE) and apparent diet digestibility, of wetting food before offering it to individually caged growing chickens.

2. Female broiler chicks (8/treatment) were given grower food ad libitum from 28–49 d of age either in the dry form or wetted with 2.0 kg water/kg air dry food, or wet food restricted to the same daily amount of dry matter as eaten by the dry‐fed birds. Ad libitum feeding of the wet food significantly increased food intake and body weight gain, compared to dry feeding, while weight gains of birds with restricted feeding of wet food were intermediate.

3. Experiments 2 and 3 studied the effects of the time interval between mixing the food with water and offering it to the birds. When pre‐soaking times of 0, 12 and 24 h were compared with dry food for male broilers (8/treatment) from 25 to 40 d all wet treatments increased body weight gains significantly, the best results coming from the zero soaking time, when DM digestibility was increased significantly from 677 to 714 g/kg. When restricted amounts of food were offered hourly for 8 h on each of 4 d, DM digestibility was significantly increased from 634 for dry food to 659 for that freshly mixed with water and 664 g/kg for that soaked for 1 h between mixing and offering.

4. In a factorial experiment with wet and dry food, either in the standard form or with added enzyme or 400 g/kg cornflour, there were significant positive effects on growth and FCE of broilers (7/treatment) attributable to enzyme and wetting, while cornflour significantly reduced growth. However, wet cornflour‐diluted food gave better growth than dry standard food. Wetting significantly increased the apparent digestibility of dry matter and protein while dilution with cornflour significantly reduced protein digestibility.

5. These results confirm those previously presented in terms of improved growth and FCE with wet feeding and demonstrate a large improvement in the proportion of the food absorbed from the digestive tract, of similar magnitude to the improvement in FCE. They also show that it is not necessary to pre‐soak food in order to attain the maximum effect.     

Oral administration of lysine restores food intake and ventromedial hypothalamic dopamine in chicken on a lysine-free diet

1. This study was conducted to examine whether oral administration of lysine solution affect food intake and the ventromedial hypothalamic (VMH) monoamines in chickens fed on a lysine-free diet.

2. Chickens were assigned to four treatment groups. Two groups of chickens were given two different doses of lysine solution (0·1?g and 0·07?g in 1?ml of saline) exogenously (orally) while being fed on a lysine-free diet, and these results were compared with a control diet plus saline group. Another group of chickens was fed on a lysine-free diet without lysine supplementation, and their results were compared with the lysine treated groups. The extracellular dopamine (DA), norepinephrine (NE) and serotonin (5-HT) in the VMH of freely moving chicken were measured by in vivo microdialysis.

3. There was no significant difference in food intake between the control diet and the lysine supplemented groups during the time-course of the experiments. Food intake significantly decreased at 4, 5 and 6?h in the lysine-free diet plus saline group compared with the lysine supplemented groups. Of the VMH monoamines, the DA concentration remained close to the baseline in the lysine supplemented groups. This DA concentration was significantly lower than the baseline in the lysine-free diet plus saline group at 3·5?h and thereafter.

4. No significant difference from the baseline was observed for NE in the lysine-free diet plus saline group. The 5-HT concentrations were close to the baseline for all groups throughout the experiments.

5. The findings suggest that oral administration of lysine solution to chickens fed on a lysine-free diet restored food intake which was associated with the variations of VMH DA concentration.     

Influence of a high-protein diet on energy balance in obese cats allowed ad libitum access to food

The influence of a high-protein [HP, 47% of metabolizable energy (ME)] diet on energy balance was evaluated in obese cats allowed ad libitum access to food. Energy intake, body weight, body composition, energy expenditure, and concentrations of hormones and metabolites associated with carbohydrate and lipid metabolism (glucose, insulin, free fatty acids, triglycerides and leptin) were measured in cats after consuming either a moderate protein (MP, 27% of ME) or HP diet for 4 months. Indirect respiration calorimetry showed that resting and total energy expenditure (kJ/day) adjusted for either body weight or lean body mass was increased in cats consuming the HP in relation to MP diets. However, voluntary energy intake also was increased in the HP treatment and, thus, there was no difference in body weight between animals consuming the two diets. Body composition measurements using deuterium oxide dilution showed that dietary protein content did not alter amounts of either lean body mass or fat mass. No significant differences (p > 0.05) were observed between the two treatment groups for blood glucose, free fatty acid or leptin concentrations, although there was a trend (p = 0.054) towards an increase of serum insulin concentrations in the cats eating the HP diet. This study showed that short-term ad libitum feeding of an HP diet did not reduce food intake or promote weight loss in obese cats. However, energy expenditure was increased in the HP diet group and it is possible that this effect of HP might help promote weight loss when energy intake is restricted.     

Comparison of a commercial limited-antigen diet versus home-prepared diets in the diagnosis of canine adverse food reaction

The objective of the present study was to compare the efficacy of a commercial limited-antigen diet (Eukanuba Veterinary Diets Response Formula FP/Canine, The Iams Company) with home-prepared diets in the diagnosis of adverse food reaction in dogs. The study was conducted in two phases. The first phase utilized 28 dogs fed a home-prepared diet to enable a diagnosis of adverse food reaction. Dogs diagnosed from this phase were entered into the second phase in which these dogs were fed the commercial limited-antigen diet. Owners of 10 of the 28 dogs quit Phase 1 before it could be completed, and one case was eliminated because extended treatment with steroids was required. Eight of the remaining 17 (47 %) dogs were diagnosed with an adverse food reaction. A reaction occurred in four of eight dogs fed the test diet in Phase 2. These results demonstrated the difficulties encountered by owners and veterinarians attempting to feed dogs home-prepared diets. In addition, the results of the study suggest that the occurrence of adverse reactions to fish could make it a less desirable ingredient as a limited antigenin canine diets.     

The diet,food selectivity and niche of Rhabdosargus sarba (Teleostei: Sparidae) in Natal estuaries

The juveniles and subadults of Rhabdosargus sarba are one of the most common components of the benthic fish community of Natal estuaries. The diet consists mainly of aquatic macrophytes and filamentous algae although a significant proportion is made up of bivalves and the amphipod Grandidierella lignorum. The last two taxa are positively selected when little plant material is consumed. R. sarba feeds during daylight with a peak in the early afternoon. The relationship between R. sarba and the very similar sympatric R. holubi and R. auriventris are discussed in relation to their diet, divergence and distribution. Resource partitioning in Natal estuaries between R. sarba, the Gerreidae and Pomadasys commersonii is also discussed.     

Variation in food selection among lambs: effects of basal diet and foods offered in a meal.

In studies of behavior and nutrition, we typically determine nutritional needs and formulate diets for the average member of the herd, not for specific individuals within a herd. Nevertheless, variation among individuals could affect productivity of the group if the diet diverges too much from what individuals at the extremes prefer to eat. Thus, it is important to determine the degree to which individuals within a group vary in their food preferences when offered alternatives. Our first objective was to determine the degree to which lambs differed in preference for foods high in energy (barley) or protein (alfalfa) (Exp. 1). When we offered lambs barley and alfalfa for ad libitum consumption for 25 d, individuals varied in the amounts of barley (range: 221 to 991 g/d) and alfalfa (range: 51 to 558 g/d) they consumed (P < .0001). At one extreme, individuals preferred a diet of 6% alfalfa and 94% barley; at the other extreme, individuals preferred a diet of 70% alfalfa and 30% barley. Our second objective was to determine whether lambs from Exp. 1 compensated, when fed a basal diet that was lower in alfalfa than they preferred, by ingesting foods higher in alfalfa when offered a meal (Exp. 2). Lambs were ranked according to the percentage of alfalfa (range from 6 to 70%) and barley (range from 94 to 30%) they ate during Exp. 1 and then assigned alternately to two treatments: 1) basal diet with similar proportions of alfalfa and barley consumed ad libitum (preferred diet) or 2) basal diet with 10% less alfalfa than consumed ad libitum (low-alfalfa diet). We then conducted three trials in which lambs fed the different basal diets were offered a meal for 15 min/d for 2 d of two foods that differed in barley and alfalfa. During Trial 1, when we offered barley and alfalfa, lambs in both groups preferred barley (138 g) to alfalfa (46 g) (P < .05). During Trial 2, when the test foods (barley and alfalfa) were diluted with grape pomace (20%), lambs fed the preferred basal diet ate more barley (116 vs 64 g) and less alfalfa (48 vs 87 g) than lambs fed the low-alfalfa basal diet (P < .05). During Trial 3, when we offered a food high in barley (80% barley and 20% pomace) and a food high in alfalfa (70% alfalfa, 14% cornstarch, and 16% pomace), lambs fed the preferred basal diet ate more of the high-barley food (124 vs 73 g) and less of the high-alfalfa food (45 vs 98 g) than lambs fed the low-alfalfa basal diet (P < .05). Collectively, these results illustrate that lambs varied greatly in their preferences for foods that differ in energy (barley) and protein (alfalfa), and that when their preferred basal diet was altered, lambs compensated by ingesting food that complemented their basal diet during a daily meal. The addition of grape pomace in Trials 2 and 3 reduced the protein content of the high-barley and high-alfalfa foods such that the high-barley food was only marginally adequate to meet needs compared with the high-alfalfa food. Lambs fed the low-alfalfa basal diet compensated by eating more of the high-alfalfa food than lambs fed the preferred basal diet.     

Efficacy of a commercial hydrolysate diet in eight cats suffering from inflammatory bowel disease or adverse reaction to food

Eight of 28 cats presenting with chronic vomiting and/or diarrhoea were diagnosed as suffering from chronic enteropathy. All cats had undergone a complete diagnostic work-up, including endoscopy. Histopathology findings varied from normal, eosinophilic, to lymphoplasmacytic gastroenteritis. On the basis of findings, the cats were diagnosed with inflammatory bowel disease (IBD) or an adverse reaction to food. A hydrolysed protein diet was used as sole therapy, and clinical signs resolved within 4-8 days in all eight cats. After 2 months the cats had gained weight. A challenge trial with their previous diet resulted in recurrence of the clinical signs, which resolved in seven cats when the test diet was reintroduced. We conclude that the hydrolysed protein diet used in the current study was effective in managing these cases.     

A blinded randomized controlled trial evaluating the usefulness of a novel diet (aminoprotect care) in dogs with spontaneous food allergy

Aminoprotect Care (APC) is a novel diet composed of aminoacids, potato proteins and corn starch. The objectives of this study were to determine whether Maltese-Beagle atopic (MBA) dogs hypersensitive to corn exhibited clinical signs and changes in immunological markers after being fed APC. The study was designed as a blinded randomized controlled crossover experiment. Ten MBA dogs with signs of allergy within five days of ingesting corn were selected. Dogs were randomized to be fed either their maintenance diet with corn or APC for five days. After a washout of two weeks, diets were switched. Before and daily during each intervention, skin lesions were graded by an investigator while pruritus was assessed by another. Before and at the end of each intervention, the percentage of circulating CD4+CCR4+, corn-activated CD4+ T-lymphocytes and serum corn-specific IgE levels were measured and ratios of post:pre values calculated. During this trial, pruritus and skin lesions increased significantly in MBA dogs when ingesting corn while no such increase occurred when fed APC. Total, median and maximal pruritus values were significantly higher in MBA dogs ingesting corn compared to APC. There were no significant differences between interventions in the immunological parameters assessed. In summary, even though APC contains corn starch to which corn-sensitive MBA dogs often react, the ingestion of APC did not lead to significant increases in skin lesions or pruritus. Aminoprotect Care might prove valuable for management of food allergies. These experimental observations must be validated in large field studies.     

Influence of food input and procedure of determination on metabolisable energy and digestibility of a diet measured with young and adult birds

Two series of balance trials were performed with adult cockerels and with broiler chickens during their 5th week of life, and one with adult colostomised hens. The latter served to determine the digestibility of protein of the diet under test. All birds were fed the same diet with one exception: in the case of colostomised hens limestone (100 g/kg) was added before feeding. The main purpose of the experiments was to compare the Sibbald procedure for determining the so-called true metabolisable energy (TME) with apparent metabolisable energy (AME) or TME values obtained by applying a conventional addition method (CAM). The results showed that the Sibbald procedure was less precise than CAM. The Sibbald procedure delivered incorrect TME and AME values, the reason for this being the use of starved birds. This led not only to wrong intercepts but also to misleading regression coefficients in the regression equations used to calculate energy excretion on food intake. In CAM there existed no differences between AME and TME. This was not true for the Sibbald procedure, in which AME values differed considerably from TME values. Because of the errors inherent in the Sibbald procedure it is suggested that it should be replaced by CAM, in which several feeding inputs should be used.     

慎对餐桌上的革命"克隆食品"再起争论

就在转基因食品的安全性还在越来越受到人们的广泛关注之际,2008年年初,欧盟和美国的食品安全部门分别宣布,食用克隆食品是安全的,相继为克隆食品开了绿灯,也许不久后克隆食品就会象转基因食品一样被摆上普通百姓的餐桌。克隆食品上餐粜,这在人类历史上尚属首次。或许,继转基因技术之后,克隆技术又将带来一次餐桌上的“革命”。