Food-specific sublingual immunotherapy is well tolerated and safe in healthy dogs: a blind, randomized, placebo-controlled study.

BACKGROUND: Food allergies are increasing in prevalence but no treatment strategies are currently available to cure dogs with food allergy. Over the past decade, experimental food allergen-specific sublingual immunotherapy (FA-SLIT) has emerged as a potential treatment for food allergies in human medicine. However, FA-SLIT has not been investigated in dogs. Therefore, the objective of this study was to prospectively evaluate the safety, tolerability and dispenser sterility of FA-SLIT in healthy dogs before testing it in food allergic dogs. Eight experimental healthy beagle dogs, never orally exposed to peanut, were randomized in two groups to receive SLIT with peanut or placebo for 4 months. Subjects were monitored daily for local and systemic adverse effects. Blood samples for complete blood count and serum biochemistry, and urine for urinalysis were collected and the dogs' body weight was recorded at day 0, 35 and 119 of the SLIT treatment. Sera for the determination of peanut-specific IgG and IgE were collected at day 0, 35, 49, 70, 91, 105 and 119. Intradermal tests were performed before (day 0) and after (day 119) the experiment. The content of each dispenser used to administer treatment or placebo was tested for sterility after usage. In order to assess the presence or absence of sensitization, dogs were challenged 6 months after the end of the study with 2000 µg of peanut extract daily for 7 to 14 days. RESULTS: All dogs completed the study. The treatment did not provoke either local or systemic side-effects. Peanut-specific IgG significantly increased in treatment group. Even though a significant increase in peanut-specific IgE was also seen, intradermal tests were negative in all dogs before and after the experiment, and the challenge test did not trigger any adverse reactions in the treated dogs, which shows the protocol did not cause sensitization to peanut, but nevertheless primed the immune system as indicated by the humoral immune response. All dispenser solutions were sterile. CONCLUSIONS: Our results demonstrate that the used peanut-SLIT protocol is well tolerated and safe in healthy dogs. Further studies should evaluate tolerability, safety and efficacy in dogs with food allergy.

Predictive equations of selenium accessibility of dry pet foods.

The trace element selenium is essential to both dogs and cats. Dry diets are formulated with a large range of ingredients, which may vary in selenium concentration and accessibility. This paper reports equations to predict the average in vitro selenium accessibility from dry pet foods based on essential dietary nutrient concentrations, including crude protein, amino acids and crude fat. Predictive equations were made using stepwise linear regression for extruded and pelleted diets. The equations can be used to aid diet formulation to optimize selenium accessibility within the diet and to prevent selenium deficiency or toxicity.

Secreted phospholipase A2 inhibitor modulates fatty acid composition and reduces obesity-induced inflammation in Beagle dogs.

Secreted phospholipase A2 inhibitor (sPLA2i) has been reported to have an anti-inflammatory function by blocking the production of inflammatory mediators. Obesity is characterized by low-grade inflammation and oxidative stress. The aim of this study was to investigate the effects of dietary supplementation of sPLA2i on inflammation, oxidative stress and serum fatty acid profile in dogs. Seven obese and seven lean Beagle dogs were used in a 28-day double blind cross-over design. Dogs were fed a control diet without supplemental sPLA2i or an sPLA2i supplemented diet. The sPLA2i diet decreased plasma fibrinogen levels and increased the protein:fibrinogen ratio in obese dogs to levels similar to those of lean dogs fed the same diet. Obese dogs had a higher plasma concentration of the lipophilic vitamin A with potential antioxidative capacity and a lower ratio of retinol binding protein 4:vitamin A compared to lean dogs, independent of the diets. A higher proportion of myristic acid (C14:0) and a lower proportion of linoleic acid (C18:2n-6) were observed in the dogs fed with the sPLA2i diet compared to dogs fed with the control diet. Furthermore, a higher ratio of n-6 to n-3, a lower proportion of n-3 polyunsaturated fatty acids and lower omega-3 index were observed in obese compared to lean dogs. The results indicate that obese dogs are characterized by a more 'proinflammatory' serum fatty acid profile and that diet inclusion of sPLA2i may reduce inflammation and alter fatty acid profile.

Biological effects of short-term salmon oil administration, using distinct salmon oil sources in healthy dogs.

OBJECTIVES: To assess the short-term effects of feeding distinct salmon oil sources in healthy dogs. METHODS: A diet containing chicken fat as major fat source was fed to 17 dogs for 14 days. For the next 14 days, dogs received one of two diets, both with 1% of chicken fat exchanged for 1% salmon oil; Norwegian or Scottish salmon oil, harvested using a distinct procedure. Finally, all dogs were fed chicken fat again for 14 days. RESULTS: Salmon oil increased serum phospholipid total n-3 polyunsaturated fatty acids, eicosapentaenoic and docosahexaenoic acid and decreased total n-6 polyunsaturated fatty acids and n-6:n-3. The phospholipid fatty acid profile returned to initial values within 2 weeks of discontinuing salmon oil administration. Blood coagulation, acute phase response and plasma immunoglobulin concentrations were not affected by salmon oil and no differences were detected for the measured indices between the two salmon oils. CLINICAL SIGNIFICANCE: Low-dose salmon oil administration alters serum phospholipid fatty acid profile within 2 weeks, but without affecting selected immunologic and coagulation indices. Salmon oil sources from different sources and harvested using a distinct procedure did not induce different effects, most probably because of their similar fatty acid profiles.

Blood values of adult captive cheetahs (Acinonyx jubatus) fed either supplemented beef or whole rabbit carcasses.

This study evaluated nutrient intake and relevant blood parameters of 14 captive cheetahs, randomly assigned to a meat-only diet (supplemented beef, SB) or a whole prey diet (whole rabbit, WR) for 4 weeks each. Despite a higher food intake, daily metabolizable energy intake was lower when fed WR (308 kJ BW(-1) ) compared with SB (347 kJ BW(-1) ) (P = 0.002). The ratio of protein to fat was markedly lower for WR (2.3:1) compared with SB (8.8:1), which was reflected in higher serum urea levels when fed SB (P = 0.033), and a tendency for elevated cholesterol levels when fed WR (P = 0.055). Taurine intake of cheetahs fed WR was low (0.06% on DM basis); however, analytical error during taurine analysis cannot be ruled out. Feeding WR resulted in a well-balanced mineral intake, in contrast to SB. The latter provided a low calcium:phosphorus ratio (1:2.3), thereby increasing the risk of metabolic bone disease. The high zinc content of SB (200 mg/kg DM), compared with WR (94 mg/kg DM), was reflected in higher serum zinc concentrations (P = 0.011). Feeding WR resulted in an increase in serum vitamin A (P = 0.011). Therefore, the risk of hypervitaminosis A in captive cheetahs when fed WR exclusively on a long-term basis should be evaluated. Our findings suggest that neither diet is likely to provide appropriate nutrition to captive cheetahs when fed exclusively.

The effect of vitamin C supplementation in healthy dogs on antioxidative capacity and immune parameters.

The aim of the study was to investigate the ability of vitamin C to increase the antioxidative and immunomodulating potential in healthy dogs. Fifteen dogs were tested for the effects of orally administered vitamin E (60 mg dl-alpha tocopheryl acetate) in combination with vitamin C (0, 30 or 60 mg ascorbic acid crystalline). Three treatments (0, 30, 60 mg vitamin C) were tested in a 3 x 3 cross-over study in three periods of 36 days. Pre-prandial blood samples were taken for analysis of vitamins C, E, A, retinyl palmitate and stearate, antioxidant status [Thiobarbituric acid reactive substances (TBARS) and uric acid], biochemical and haematological analysis. Subpopulations of lymphocytes, mitogen-induced peripheral blood mononuclear cell proliferation (PBMC) and serum IgA and IgG concentrations were determined. There was a trend (p = 0.056) for an increased plasma vitamin C concentration by vitamin C supplementation. There was no evidence that dietary treatment altered neither the other plasma vitamin concentrations nor TBARS and uric acid concentrations nor the subpopulations of the lymphocytes except for the number of CD4+ lymphocytes that increased with vitamin C supplementation. There was no effect of vitamin C on serum IgA and IgG concentration. A significant time x treatment interaction was demonstrated on PBMC's to pokeweed, with an increase observed by 30 mg vitamin C supplementation but a decrease by 60 mg vitamin C supplementation. There was no clear evidence for an effect of dietary vitamin C on antioxidative capacity in healthy dogs fed a diet with vitamin E concentrations well above the recommendations. Yet, a limited number of immunological parameters were slightly affected.

The effects of inulin supplementation of diets with or without hydrolysed protein sources on digestibility, faecal characteristics, haematology and immunoglobulins in dogs.

Dogs with food allergy are often treated by giving a diet with hydrolysed protein sources. Prebiotics might also be successful in prevention and treatment of allergic disease through their effect on the colonic microflora, analogous to studies on probiotics in allergic children. The present study was set up to investigate the effect of supplementing inulin (IN) to commercial hypoallergenic dog diets on apparent nutrient digestibility, faecal characteristics, haematology and Ig in dogs. Supplementation of 3 % IN did not affect faecal pH, food and water intake and urine production. Compared with the intact protein diet with a limited number of ingredients (L), the diet with a hydrolysed protein source (H) resulted in an increased water intake (P<0.001), which could be due to the osmotic effect of free amino acids. Faeces production was increased by IN due to increased faecal moisture content. Increased faeces production on the H diet was mainly due to a higher DM excretion. Subsequently, the apparent digestibility coefficient (ADC) of DM was lower in the H diet group. A similar result was noted for ADC of diethyl ether extract and crude ash. The ADC of crude protein was higher in the H diet group, whereas IN decreased the ADC of crude protein. Differences in the ADC of crude protein among the different diets disappeared after correction for a higher faecal biomass, except for the dogs fed the L+IN diet. Total faecal IgA concentrations were lower in the H group (P<0.05) because of lower antigenic stimulation of hydrolysed protein, which implies that hydrolysed protein is really hypoallergenic. The present study indicates that the use of hydrolysed protein diets for canine food allergy treatment can affect digestibility and that combination with IN affected apparent protein digestibility but not IgA response.

The effect of oligofructose on urea metabolism and faecal odour components in cats.

The effect on urea metabolism by the supplementation of oligofructose to a reduced protein diet was evaluated in cats by the use of labelled urea. The effect on faecal odour was also evaluated. Four cats were tested in a crossover study with two treatments: control and fructo-oligosaccharide (FOS). The FOS was supplemented at 3.11% on dry matter (DM) basis to a reduced protein diet (28.9% DM). After an adaptation period of 3 weeks, faeces and urine were collected during a 5-day collection period. Fresh faecal samples were collected for determination of odour components. On the first day of the collection period, labelled urea was injected subcutaneously. Urine production was estimated by potassium excretion. The fresh faecal samples were incubated in an air-closed recipient with two solid-phase micro extraction (SPME) fibres to bind the produced sulphur (S)-containing components. The reduced protein diet decreased plasma urea concentration but FOS supplementation had no effect. The tendency for a higher faecal output by FOS supplementation was the consequence of both an increased moisture content and faecal DM production. Supplementation of FOS showed tendencies to increase total faecal nitrogen (N) excretion and faecal (15)N excretion and tended to decrease urinary (15)N excretion. Twenty-seven different odour components were detected but were not affected by FOS supplementation.

The impact of prebiotics and salmonellosis on apparent nutrient digestibility and Salmonella typhimurium var. Copenhagen excretion in adult pigeons (Columba livia domestica).

The effects of lactose or fructo-oligosaccharide (FOS) supplementation on the excretion of salmonellae, apparent digestibilities and excreta consistency were studied. Thirty-two male pigeons (Columba livia domestica) were randomly divided into 4 equal groups: 3 of 4 groups were orally infected with 10(9) Salmonella Typhimurium var. Copenhagen, after being offered a drinking water supplement of 2% FOS, 2% lactose, or no supplement, respectively, for 2 wk. Pigeons in the fourth group were not challenged with S. Typhimurium and remained unsupplemented. Initially, FOS increased water intake, resulting in more watery excreta. After infection, supplementation showed no major effects on S. Typhimurium excretion, nitrogen retention, or apparent nutrient digestibilities, although lactose--and to a lesser extent FOS--improved apparent fiber digestibility during recovery from the S. Typhimurium infection. The excreta consistency of all pigeons returned to normal when recovering from the Salmonella infection. In this trial, neither FOS nor lactose was successful in tempering the negative aspects of Salmonella infection in pigeons. Nevertheless, it should be stated that future investigations should clarify the importance of duration and level of prebiotic supplementation and infection level.

Prebiotics affect nutrient digestibility but not faecal ammonia in dogs fed increased dietary protein levels.

An increased protein content and less digestible protein sources in the diet can induce bad faecal odour. The present study investigated the effect of adding prebiotics to dog diets enriched with animal-derived protein sources on apparent digestibilities and faecal ammonia concentration. In three subsequent periods eight healthy beagle dogs were fed a commercial dog diet that was gradually supplemented by up to 50 % with meat and bone meal (MBM), greaves meal (GM) or poultry meal (PM) respectively. Afterwards, 3 % fructo-oligosaccharides or 3 % isomalto-oligosaccharides were substituted for 3 % of the total diet. Supplementation with animal-derived protein sources did not decrease the apparent N digestibility significantly but oligosaccharides did. On the other hand the bacterial N content (% DM) in the faeces was highest in the oligosaccharide groups followed by the protein-supplemented groups and lowest in the control groups. When the apparent N digestibility was corrected for bacterial N no significant differences were noted anymore except for the GM group where the corrected N digestibility was still lower after oligosaccharide supplementation. The amount of faecal ammonia was significantly increased by supplementing with protein or oligosaccharides in the MBM and GM groups but not in the PM group. When apparent N digestibility is interpreted, a correction for bacterial N should be taken into account, especially when prebiotics are added to the diet. Oligosaccharides did not reduce the faecal ammonia concentrations as expected.

The effect of a commercial high-fibre diet and an iso-malto-oligosaccharide-supplemented diet on post-prandial glucose concentrations in dogs.

In order to evaluate the effect of insoluble and soluble fibre on the levels of post-prandial glycaemia, six healthy dogs were fed three different diets: a low-fibre control diet, a high-fibre diet (HF; mainly insoluble fibre) and the control diet with 10% iso-malto-oligosaccharides (IMO) added. The diets were fed for 2 days before the blood collections were started on the third day. Serial blood samples were taken 20, 60, 90, 150, 180, 240 and 360 min after feeding and one sample was taken just before the feeding after a fasting period of at least 20 h. There were no problems concerning the faecal consistency. The post-prandial glycaemia curve was significantly lower in the HF and IMO group in comparison with the control group. At 20 and 60 min the glucose concentration was significantly lower in the HF and IMO groups. At 90 and 150 min only the IMO group had a significantly lower glucose concentration. At 360 min there was a trend for a lower glucose concentration in the IMO group. The results show that both the HF and the IMO diets had a beneficial effect on post-prandial hyperglycaemia. Substitution of IMO may have the same or a slightly better effect, but this has to be confirmed in diabetic dogs and the effect may depend on the composition of the basal diet.

Enhanced specific antibody response to bovine serum albumin in pigeons due to L-carnitine supplementation.

1. Thirty adult female pigeons (Columba livia domestica) were randomly divided into 3 equal groups; the 1st and 2nd groups were immunised with bovine serum albumin (BSA) at 0 and 20 d, the 2nd group also received 1 g L-carnitine per litre of drinking water from -5 to 25 d post-immunisation (dpi) and the 3rd group, a control group, received neither treatment. 2. Body weights and serum samples were taken at 0, 5, 10, 15, 20, 25, 30 and 35 dpi. 3. Both BSA-specific IgG and IgM responses were enhanced by about 10% by L-carnitine supplementation. 4. L-carnitine supplemented pigeons showed a higher water consumption. Body weight loss during the onset of the immune response showed a slight tendency to be counteracted by L-carnitine supplementation. 5. The impact of L-carnitine on resistance and resilience to an immunological challenge is discussed.

L-carnitine supplementation in breeding pigeons: impact on zootechnical performance and carnitine metabolism.

In the first experiment (Exp1), three consecutive breeding rounds were performed by two groups of six pigeon couples in order to study the impact of L-carnitine supplementation (80 mg x d(-1)) of parent pigeons on zootechnical performance. Both in the second and third experiments (Exp2, Exp3), one breeding round was performed by two groups of six pigeon couples to reveal the biochemical background of the increase in squab growth, the limitation of body weight decrease in male parent birds and the tendency for an improved cumulative feed efficiency due to L-carnitine supplementation in Exp1. Growth improvement of the squabs with L-carnitine was only seen when the parent pigeons were supplemented, together with a marked rise in the body weight of the parent birds around hatching. Based on the results of the crop milk analysis, growth improvement was probably due to a quantitative impact on crop milk production. The crop milk from the supplemented groups in both Exp2 and Exp3 had increased levels of carnitine. Carnitine, gamma-butyrobetaine and acetylcarnitine were increased in plasma samples of the supplemented parent pigeons. No differences were present in the squabs' plasma for these parameters. In the squabs of Exp3, no changes were seen in the proportional growth or the protein content of the heart, breast muscle and liver, but the breast muscle of the squabs from the supplemented group in Exp3 showed a considerable rise in carnitine and a marked decrease in gamma-butyrobetaine.