Healthy Ageing Is Associated with Preserved or Enhanced Nutrient and Mineral Apparent Digestibility in Dogs and Cats Fed Commercially Relevant Extruded Diets.

Age-related changes in gastrointestinal function have been reported in companion animals, but the impact on digestive efficiency remains uncertain. Healthy dogs (n = 37; 2.6-14.2 years) received four diets varying in total dietary fibre (TDF; 6-29%, as fed). Healthy cats (n = 28; 1-13 years) received four diets with two fat (10-12%; 17-18%) and TDF (9 and 12%) levels. In a crossover design, diets were provided over four consecutive 10-day cycles, including a 4-day faecal collection. Apparent crude protein (CP), ether extract (EE), TDF, calcium (Ca), and phosphorus (P) digestibilities were determined. The effect of age was analysed as a continuous variable in dogs and as differences between adult (1-5 years) and senior (7-13 years) cats. In dogs, EE digestibility was unaffected by age (p > 0.10). Dogs of 6-12 years had higher digestibility of CP (p = 0.032), TDF (p = 0.019), Ca (p = 0.019), and P (p = 0.024) when fed the 6% TDF diet. Senior cats had greater digestibility of TDF (p < 0.01) and Ca (p = 0.024) but had lower EE and CP digestibility with one diet (17% fat; 9%TDF) (age, p > 0.10; diet × age, p < 0.001). Healthy ageing was associated with preserved nutrient digestibility in dogs and cats within the age ranges studied. The effect of ingredient sources in senior cats warrants further investigation.

Astaxanthin stimulates cell-mediated and humoral immune responses in cats.

Astaxanthin is a potent antioxidant carotenoid and may play a role in modulating immune response in cats. Blood was taken from female domestic shorthair cats (8-9 mo old; 3.2 ± 0.04 kg body weight) fed 0, 1, 5 or 10mg astaxanthin daily for 12 wk to assess peripheral blood mononuclear cell (PBMC) proliferation response, leukocyte subpopulations, natural killer (NK) cell cytotoxic activity, and plasma IgG and IgM concentration. Cutaneous delayed-type hypersensitivity (DTH) response against concanavalin A and an attenuated polyvalent vaccine was assessed on wk 8 (prior to vaccination) and 12 (post-vaccination). There was a dose-related increase in plasma astaxanthin concentrations, with maximum concentrations observed on wk 12. Dietary astaxanthin enhanced DTH response to both the specific (vaccine) and nonspecific (concanavalin A) antigens. In addition, cats fed astaxanthin had heightened PBMC proliferation and NK cell cytotoxic activity. The population of CD3(+) total T and CD4(+) T helper cells were also higher in astaxanthin-fed cats; however, no treatment difference was found with the CD8(+) T cytotoxic and MHC II(+) activated lymphocyte cell populations. Dietary astaxanthin increased concentrations of plasma IgG and IgM. Therefore, dietary astaxanthin heightened cell-mediated and humoral immune responses in cats.

Dietary fish oil and flaxseed oil suppress inflammation and immunity in cats.

The modulatory activity of dietary n-3 fatty acids on inflammation and immune response in domestic cats is unknown. Mature female cats (n=14/treatment) were fed control, fish oil or flaxseed oil diets with n-6:n-3 fatty acid ratios of 20:1, 5:1 and 5:1, respectively, for 12 wk. Immune response was assessed on wk 0, 6 and 12, and skin hypersensitivity response on wk 6 and 12. Fish oil increased (P<0.01) eicosapentaenoic and docosahexaenoic acids in plasma and skin, whereas flaxseed oil increased α-linolenic acid. Fish and flaxseed oils decreased (P<0.01) skin inflammatory response to histamine. Cats fed fish but not flaxseed oil had higher (P<0.05) skin leukotriene LTB(5), but not LTB(4). Fish and flaxseed oils lowered B, total T and T(h) subset populations, and leukocyte proliferative response to PWM (P<0.05). In contrast, there was no change in ConA- or PHA-induced lymphocyte proliferation, Tc and MHC II cell populations, DTH response, NK cytotoxicity, IL-2 production, or plasma IgG concentrations. Therefore, fish and flaxseed oil can reduce skin inflammatory responses in cats, however, flaxseed oil appears less immunosuppressive than fish oil.

Dietary astaxanthin enhances immune response in dogs.

No information is available on the possible role of astaxanthin on immune response in domestic canine. Female Beagle dogs (9-10 mo old; 8.2 ± 0.2 kg body weight) were fed 0, 10, 20 or 40 mg astaxanthin daily and blood sampled on wk 0, 6, 12, and 16 for assessing the following: lymphoproliferation, leukocyte subpopulations, natural killer (NK) cell cytotoxicity, and concentrations of blood astaxanthin, IgG, IgM and acute phase proteins. Delayed-type hypersensitivity (DTH) response was assessed on wk 0, 12 and 16. Plasma astaxanthin increased dose-dependently and reached maximum concentrations on wk 6. Dietary astaxanthin enhanced DTH response to vaccine, concanavalin A-induced lymphocyte proliferation (with the 20mg dose at wk 12) and NK cell cytotoxic activity. In addition, dietary astaxanthin increased concentrations of IgG and IgM, and B cell population. Plasma concentrations of C reactive protein were lower in astaxanthin-fed dogs. Therefore, dietary astaxanthin heightened cell-mediated and humoral immune response and reduced DNA damage and inflammation in dogs.

Pigmented potato consumption alters oxidative stress and inflammatory damage in men.

Pigmented potatoes contain high concentrations of antioxidants, including phenolic acids, anthocyanins, and carotenoids. These bioactive compounds have been implicated in the inhibition or prevention of cellular oxidative damage and chronic disease susceptibility. We assessed the effects of pigmented potato consumption on oxidative stress and inflammation biomarkers in adult males. Free-living healthy men (18-40 y; n = 12/group) consumed 150 g of cooked white- (WP), yellow- (YP), or purple-flesh potatoes (PP) once per day for 6 wk in a randomized study. Blood was collected at baseline and wk 6 to analyze total antioxidant capacity (TAC), DNA damage as assessed by plasma 8-hydroxydeoxyguanosine (8-OHdG), protein oxidation, lipid peroxidation, C-reactive protein (CRP), inflammatory cytokines, lymphoproliferation, NK cytotoxicity, and phenotypes. Potatoes were analyzed for TAC, phenolic acids, anthocyanins, and carotenoids. Compared with the WP group, the YP group had higher concentrations of phenolic acids (P < 0.002) and carotenoids (P < 0.001), whereas the PP group had higher concentrations of phenolic acids (P < 0.002) and anthocyanins (P < 0.001). Men who consumed YP and PP tended to have lower (P < 0.08) plasma IL-6 compared with those consuming WP. The PP group tended to have a lower plasma CRP concentration than the WP group (P = 0.07). The 8-OHdG concentration was lower in men who consumed either YP or PP compared with WP. Pigmented potato consumption reduced inflammation and DNA damage in healthy adult males. This offers consumers an improved nutritional choice in potato consumption.

Safety and tolerance of dietary supplementation with a canine-derived probiotic (Bifidobacterium animalis strain AHC7) fed to growing dogs.

Although probiotics are generally considered to be safe, their increasingly widespread use warrants better understanding of their risks in companion animals. This study evaluated the safety and tolerance of dietary supplementation with a canine-derived probiotic, Bifidobacterium animalis strain AHC7 (Prostora, Procter & Gamble Pet Care), fed to growing beagles beginning at approximately 6 months of age (11 males; 9 females). Probiotic B. animalis AHC7 administered orally once per day at a dose of up to 5 x 1010 colony-forming units for at least 12 consecutive weeks was well tolerated with no safety concerns.

Effect of astaxanthin supplementation on inflammation and cardiac function in BALB/c mice.

Astaxanthin is an antioxidant with immunomodulatory, anti-inflammatory and anticancer properties. This study evaluated the use of dietary astaxanthin to decrease oxidative stress and improve cardiac function, thereby providing a potential cardioprotective supplement. Female BALB/c mice (8 weeks of age) were fed a semi-synthetic diet containing 0, 0.02 or 0.08% astaxanthin for 8 weeks. Cardiac function was assessed by echocardiography bi-weekly, and blood and tissue samples were collected at 8 weeks. Plasma astaxanthin concentrations increased (p<0.05) dose-dependently to 0.5 and 4 mumol/l in the astaxanthin-supplemented mice. Blood glutathione concentrations and lymphocyte mitochondrial membrane potential were not significantly affected by astaxanthin treatment. However, mice fed 0.08% astaxanthin had higher (p<0.05) heart mitochondrial membrane potential and contractility index compared to the control group. These results support the possible use of dietary astaxanthin for cardiac protection.

Effect of dietary astaxanthin at different stages of mammary tumor initiation in BALB/c mice.

The effects of astaxanthin on tumor growth, cardiac function and immune response in mice were studied. Female BALB/c mice were fed a control diet (diet C) for 8 weeks, 0.005% astaxathin for 8 weeks (diet A), or diet C for weeks 1-5 followed by diet A thereafter (diet CA). Mice were injected with a mammary tumor cell line on day 7 and tumor growth was measured daily. Mice fed diet A had extended tumor latency and lower tumor volume (p<0.05). Interestingly, those fed diet CA showed the fastest tumor growth. Astaxanthin feeding elevated plasma astaxanthin concentrations; there was no difference in plasma astaxanthin between mice fed CA and those fed A. Mice fed diet A, but not CA, had a higher (p<0.05) natural killer cell subpopulation and plasma interferon-gamma concentration compared to those fed diet C. Astaxanthin delayed tumor growth and modulated immune response, but only when astaxanthin was given before tumor initiation. This suggests that an adequate blood astaxanthin status is needed to protect against tumor initiation; conversely, astaxanthin supplementation after tumor initiation may be contraindicated.

Astaxanthin uptake in domestic dogs and cats.

BACKGROUND: Research on the uptake and transport of astaxanthin is lacking in most species. We studied the uptake of astaxanthin by plasma, lipoproteins and leukocytes in domestic dogs and cats. METHODS: Mature female Beagle dogs (18 to 19 mo old; 11 to 14 kg BW) were dosed orally with 0, 0.1, 0.5, 2.5, 10 or 40 mg astaxanthin and blood taken at 0, 3, 6, 9, 12, 18 and 24 h post-administration (n = 8/treatment). Similarly, mature domestic short hair cats (12 mo old; 3 to 3.5 kg body weight) were fed a single dose of 0, 0.02, 0.08, 0.4, 2, 5, or 10 mg astaxanthin and blood taken (n = 8/treatment) at the same interval. RESULTS: Both dogs and cats showed similar biokinetic profiles. Maximal astaxanthin concentration in plasma was approximately 0.14 mumol/L in both species, and was observed at 6 h post-dosing. The plasma astaxanthin elimination half-life was 9 to 18 h. Astaxanthin was still detectable by 24 h in both species. In a subsequent study, dogs and cats were fed similar doses of astaxanthin daily for 15 to 16 d and astaxanthin uptake by plasma, lipoproteins, and leukocytes studied. In both species, plasma astaxanthin concentrations generally continued to increase through d 15 or 16 of supplementation. The astaxanthin was mainly associated with high density lipoprotein (HDL). In blood leukocytes, approximately half of the total astaxanthin was found in the mitochondria, with significant amounts also associated with the microsomes and nuclei. CONCLUSION: Dogs and cats absorb astaxanthin from the diet. In the blood, the astaxanthin is mainly associated with HDL, and is taken up by blood leukocytes, where it is distributed to all subcellular organelles. Certain aspects of the biokinetic uptake of astaxanthin in dogs and cats are similar to that in humans.

Astaxanthin decreased oxidative stress and inflammation and enhanced immune response in humans.

BACKGROUND: Astaxanthin modulates immune response, inhibits cancer cell growth, reduces bacterial load and gastric inflammation, and protects against UVA-induced oxidative stress in in vitro and rodent models. Similar clinical studies in humans are unavailable. Our objective is to study the action of dietary astaxanthin in modulating immune response, oxidative status and inflammation in young healthy adult female human subjects. METHODS: Participants (averaged 21.5 yr) received 0, 2, or 8 mg astaxanthin (n = 14/diet) daily for 8 wk in a randomized double-blind, placebo-controlled study. Immune response was assessed on wk 0, 4 and 8, and tuberculin test performed on wk 8. RESULTS: Plasma astaxanthin increased (P < 0.01) dose-dependently after 4 or 8 wk of supplementation. Astaxanthin decreased a DNA damage biomarker after 4 wk but did not affect lipid peroxidation. Plasma C-reactive protein concentration was lower (P < 0.05) on wk 8 in subjects given 2 mg astaxanthin. Dietary astaxanthin stimulated mitogen-induced lymphoproliferation, increased natural killer cell cytotoxic activity, and increased total T and B cell subpopulations, but did not influence populations of Thelper, Tcytotoxic or natural killer cells. A higher percentage of leukocytes expressed the LFA-1 marker in subjects given 2 mg astaxanthin on wk 8. Subjects fed 2 mg astaxanthin had a higher tuberculin response than unsupplemented subjects. There was no difference in TNF and IL-2 concentrations, but plasma IFN-gamma and IL-6 increased on wk 8 in subjects given 8 mg astaxanthin. CONCLUSION: Therefore, dietary astaxanthin decreases a DNA damage biomarker and acute phase protein, and enhances immune response in young healthy females.

Clinical benefits of probiotic canine-derived Bifidobacterium animalis strain AHC7 in dogs with acute idiopathic diarrhea.

This study evaluated the effect of supplementation with canine-derived probiotic Bifidobacterium animalis strain AHC7 (lams Prostora, Procter & Gamble Pet Care) on the resolution rate of acute idiopathic diarrhea in dogs randomly assigned to receive a placebo (n=18) or the probiotic (n=13). Nutritional management with the probiotic fed at 2 x 10(10) CFU/day significantly reduced the time to resolution (3.9 +/- 2.3 versus 6.6 +/- 2.7 days; P < .01) and reduced the percentage of dogs that were administered metronidazole (38.5% versus 50.0%) compared with placebo. Probiotic B. animalis AHC7 may provide veterinarians another tool for management of acute diarrhea in dogs.

Soy isoflavones modulate immune function in healthy postmenopausal women.

BACKGROUND: The immune system may be compromised after menopause because of the effects of aging and diminishing concentrations of estrogen, an immune-modulating hormone. Isoflavones, plant-derived compounds with estrogenic and antioxidant properties, may offer immunologic benefits to women during this stage of life. OBJECTIVE: The objective of this study was to evaluate the effects of soy isoflavones, both in soymilk and in supplement form, on markers of immunity and oxidative stress in postmenopausal women. DESIGN: Postmenopausal women aged 50-65 y (n = 52) enrolled in this 16-wk double-blind, placebo-controlled trial were randomly assigned to 1 of 3 experimental groups: 1) control, 706 mL cow milk/d plus a placebo supplement; 2) soymilk, 71.6 mg isoflavones derived from 706 mL soymilk/d plus a placebo supplement; and 3) supplement, 70 mg isoflavones in a supplement plus 706 mL cow milk/d. Plasma and 24-h urine samples were obtained at baseline and at 16 wk. Immune variables included lymphocyte subsets, cytokine production, and markers of inflammation and oxidative damage. RESULTS: Isoflavone intervention in postmenopausal women resulted in higher (P < 0.05) B cell populations and lower (P < 0.05) plasma concentrations of 8-hydroxy-2-deoxy-guanosine, an oxidative marker of DNA damage. Isoflavone treatment did not significantly influence concentrations of interferon gamma, interleukin 2, tumor necrosis factor alpha, or C-reactive protein in plasma or of 8-isoprostane in urine. CONCLUSIONS: Soymilk and supplemental isoflavones modulate B cell populations and appear to be protective against DNA damage in postmenopausal women.

Carotenoid action on the immune response.

Early studies demonstrating the ability of dietary carotenes to prevent infections have left open the possibility that the action of these carotenoids may be through their prior conversion to vitamin A. Subsequent studies to demonstrate the specific action of dietary carotenoids have used carotenoids without provitamin A activity such as lutein, canthaxanthin, lycopene and astaxanthin. In fact, these nonprovitamin A carotenoids were as active, and at times more active, than beta-carotene in enhancing cell-mediated and humoral immune response in animals and humans. Another approach to study the possible specific role of dietary carotenoids has used animals that are inefficient converters of carotenoids to vitamin A, for example the domestic cat. Results have similarly shown immuno-enhancement by nonprovitamin A carotenoids, based either on the relative activity or on the type of immune response affected compared to beta-carotene. Certain carotenoids, acting as antioxidants, can potentially reduce the toxic effects of reactive oxygen species (ROS). These ROS, and therefore carotenoids, have been implicated in the etiology of diseases such as cancer, cardiovascular and neurodegenerative diseases and aging. Recent studies on the role of carotenoids in gene regulation, apoptosis and angiogenesis have advanced our knowledge on the possible mechanism by which carotenoids regulate immune function and cancer.

Effects of age and dietary beta-carotene on immunological variables in dogs.

beta-Carotene is a naturally occurring carotenoid reported to have health-promoting effects in several species. Advancing age is known to have a negative impact on various immune variables in several species. This study was conducted in order to assess the effect of age on immune response in dogs and to determine whether beta-carotene is able to reverse this age-associated decline. To test this hypothesis, young and old dogs (n = 36) were fed either a control diet or experimental diets containing supplemental beta-carotene for 2-month periods. Age significantly (P < .05) lowered CD4+ T cell populations (47.2% versus 33.7%; young-control versus old-control, respectively) and beta-carotene restored percent distributions in old dogs to nonsignificance versus younger controls (41.0%). T cell proliferation was lower in old dogs (30,254 +/- 2,248 versus 14,811 +/- 2,497 cCPM; young-control versus old-control, respectively; P < .05), and beta-carotene supplementation significantly improved responses in this age group (21,329 +/- 2,275 cCPM). Although B cell proliferation was depressed with age (17,967 +/- 1,384 versus 7,535 +/- 1,469 cCPM; young-control versus old-control, respectively; P < .05), beta-carotene supplementation improved B cell proliferation in young dogs (23,500 +/- 1,339 cCPM). Old dogs displayed lower delayed-type hypersensitivity test (DTH) responses versus younger controls to both phytohemagglutinin-P (PHA; 11.1 +/- 0.95 versus 7.57 +/- 1.15 mm; young-control versus old-control, respectively; P < .05) and sheep red blood cell (RBC; 9.12 +/- 0.62 versus 8.08 +/- 0.75 mm; young-control versus old-control, respectively; P < .10). beta-Carotene improved these responses, mostly within the first 24-48 hours after injection. In summary, older dogs have lower immunological responses compared with younger controls. beta-Carotene supplementation significantly restored immune responses in older dogs when compared with their age-matched controls and younger counterparts.

Dietary lutein inhibits mouse mammary tumor growth by regulating angiogenesis and apoptosis.

Even though we previously reported that dietary lutein can inhibit mammary tumor growth, the mechanism of this action was unknown. Here, we studied the action of dietary lutein through its possible regulation of apoptosis and angiogenesis. Female BALB/c mice were fed a semi-purified diet containing 0 (control), 0.002 or 0.02% lutein (n = 20/treatment) for 2 weeks prior to inoculation with 100,000 -SA mouse mammary tumor cells into the right mammary fat pad. Tumor volume was measured daily until day 50 postinoculation when all mice were killed. Angiogenesis and apoptosis activities in the tumors were measured by immunohistochemistry. Apoptosis and necrosis of blood lymphocytes were quantitated by flow cytometry using Annexin V-FITC and propidium iodide staining. The expression of the p53, Bax and Bcl-2 mRNA was measured by RT-PCR amplification. Lutein was not detectable in the plasma, liver or tumor of unsupplemented mice, but increased in a dose-dependent manner in lutein-supplemented mice. Mice fed lutein had tumors that were 30 to 40% smaller (p < 0.05) on day 50 post-inoculation compared to unsupplemented mice. Final tumor volume was lowest in mice fed 0.002% lutein. Mice fed lutein had higher apoptotic activity in the tumors but lower apoptotic activity in blood lymphocytes as compared to unsupplemented animals. These observations were supported by the observed increase in the expression of the proapoptotic genes, p53 and Bax, together with a decrease in the expression of the antiapoptotic gene, Bcl-2, and consequently an increase in the Bax:Bcl-2 ratio in tumors from lutein-fed mice. Furthermore, lutein-fed mice also had lower (p < 0.05) angiogenic activity in the tumors as compared to unsupplemented mice. The greatest beneficial effect on apoptosis and angiogenesis was observed with mice fed 0.002% lutein. Therefore, dietary lutein, especially at 0.002%, inhibited tumor growth by selectively modulating apoptosis, and by inhibiting angiogenesis.