The effects of soy milk and isoflavone supplements on cognitive performance in healthy, postmenopausal women.

RATIONALE: The decline in estrogen concentrations in women after menopause can contribute to health related changes including impairments in cognition, especially memory. Because of the health concerns related to hormone replacement therapy (HRT), alternative approaches to treat menopausal symptoms, such as nutritional supplements and/or diet containing isoflavones, are of interest. OBJECTIVES: This study investigated whether soy isoflavones (soy milk and supplement) could improve cognitive functioning in healthy, postmenopausal women. PARTICIPANTS, INTERVENTION AND DESIGN: A total of 79 postmenopausal women, 48-65 years of age, completed a double-blind, placebo-controlled trial in which they were randomly assigned to one of three experimental groups: cow's milk and a placebo supplement (control); soy milk and placebo supplement (soy milk, 72 mg isoflavones/day); or cow's milk and isoflavone supplement (isoflavone supplement, 70 mg isoflavones/day). MEASUREMENTS: Cognitive functioning was assessed using various cognitive tasks before the intervention (baseline) and after the intervention (test). RESULTS: In contrast to predictions, soy isoflavones did not improve selective attention (Stroop task), visual long-term memory (pattern recognition), short-term visuospatial memory (Benton Visual Retention Test), or visuo-spatial working memory (color match task). Also, the soy milk group showed a decline in verbal working memory (Digit Ordering Task) compared to the soy supplement and control groups. CONCLUSION: Soy isoflavones consumed as a food or supplement over a 16-week period did not improve or appreciably affect cognitive functioning in healthy, postmenopausal women.

Uptake and immunomodulatory role of bixin in dogs.

Carotenoids are readily absorbed from the diet and distributed in blood leukocyte subcellular organelles. Bixin, a potent bioactive found in the seed of the Annatto plant, , possesses antioxidant and anti-inflammatory properties. The purpose of this study was to determine the uptake of bixin by plasma, lipoproteins, and leukocytes in domestic dogs and to examine immunoprotective properties. To determine uptake kinetics, female Beagle dogs (2 yr; 9.1 ± 0.1 kg BW) were first fed a single dose by oral gavage of 0, 5, 10, 20, or 40 mg bixin, with blood collected at 0 to 16 h after administration ( = 6/treatment), and then fed daily with 0, 5, 10, 20, or 40 mg bixin/d, with blood collected at 0, 1, 2, 4, 6, 10, and 14 d. In a consecutive experiment, cell-mediated and humoral responses as well as oxidative biomarkers were measured following 16 wk of dietary supplementation with 0, 5, 10, or 20 mg bixin/d. Maximal absorption in plasma occurred by 0.5 h with an elimination half-life of 2.6 to 3.3 h after a single dose of bixin. Steady-state plasma concentrations were 0.053 µ after 14 d of 40 mg bixin/d. The majority of subcellular bixin was found in the leukocyte mitochondria and was associated with the high-density lipoprotein and low-density lipoprotein fractions of lipoproteins. Specific (vaccine) response increased ( < 0.05) but nonspecific mitogen response was unchanged after 12 wk of dietary bixin, as assessed by a delayed-type hypersensitivity assay. Both B cell plasma leukocyte subpopulations at 6 and 16 wk and IgG plasma concentration at 12 wk in the 10-mg treatment group increased ( < 0.05), although IgM production and other cell populations were unaffected. In addition, 8-oxo-2'-deoxyguanosine (8-OHdG), a DNA damage biomarker, was substantially reduced ( < 0.05) in all treatment groups by wk 16, and C-reactive protein (CRP) was suppressed at wk 12 ( < 0.05). Dietary supplementation with bixin showed no changes in lymphoproliferation in response to in vitro mitogenic challenge and had no effect in enhancing natural killer cell activity. In conclusion, bixin was readily absorbed in a dose-dependent manner in blood following oral administration and was then taken up by leukocytes, where it was primarily distributed to mitochondria but in other subcellular organelles as well. Bixin also appeared to stimulate immune response, as seen with cell-mediated responses, and exerted anti-inflammatory (reduced CRP) as well as antioxidative (reduced 8-OHdG) effects in dogs.

Bixin uptake and antioxidative effect and role in immunoregulation in domestic cats.

Bixin, a carotenoid found in the seed of the Annatto plant, , is a potent antioxidant. Carotenoids are readily absorbed from the diet; therefore, the purpose of this study was to examine uptake of bixin by plasma, lipoproteins, and leukocytes after dietary supplementation in domestic cats and to assess effects on immune response. Female domestic short hair cats (3 yr old; 4.79 ± 0.13 kg BW) were fed a single dose of 0, 1, 5, or 10 mg bixin, and blood was taken at 0, 1, 2, 4 and 8 h after administration ( = 6/treatment) to determine acute absorption rate. Then, bixin was fed daily for 14 d to examine steady-state plasma concentrations and subcellular distribution. Following these preliminary experiments, cats ( = 8/treatment) were fed diets containing 0, 1, 5, or 10 mg bixin/d for 16 wk and blood was collected on wk 0, 6, 12, and 16 for analysis of leukocyte subpopulations, cell-mediated responsiveness, and inflammatory and oxidative biomarkers. Maximal uptake in plasma occurred 1 h after a single oral dose of bixin, with a maximal concentration of 0.119 µ and elimination half-life of 1.8 to 2.2 h. Daily feeding of bixin showed a steady-state plasma concentration of 0.110 µ at the greatest doses. Bixin was primarily associated with the high-density lipoprotein fraction of blood lipoproteins and was primarily distributed in mitochondrial fractions (58-59%) of but also in microsomal and nuclear fractions (37-44%). Leukocyte subpopulations in blood were variably affected by dietary bixin, with an increase ( < 0.05) in total T cells but a concurrent decrease ( < 0.05) in CD18+ and B cell subpopulations. However, plasma IgG increased ( < 0.05) in the 10-mg treatment group by wk 6. Lymphoproliferation was stimulated ( < 0.05) in the 5-mg bixin treatment group by wk 16, and delayed-type hypersensitivity response increased after nonspecific antigenic challenge. Conversely, when a specific challenge of vaccine was assessed on wk 12 and 16, responsiveness decreased ( < 0.05) in the 10-mg bixin treatment group. Bixin supplementation surprisingly caused an increase ( < 0.05) in α-acid glycoprotein but had no effect on natural killer cell activity, other subpopulations of leukocytes, or 8-oxo-2>-deoxyguanosine, a DNA damage biomarker. This experiment demonstrated dose-dependent uptake of bixin in plasma and blood lipoproteins and distribution in leukocyte subcellular components and an impacted immune response through cell-mediated and humoral actions.

Inhibitory effect of conjugated dienoic derivatives of linoleic acid and beta-carotene on the in vitro growth of human cancer cells.

The effects of physiologic concentrations of conjugated linoleic acid (CLA) and beta-carotene were assessed on human (M21-HPB, malignant melanoma; HT-29, colorectal; MCF-7, breast) cancer cells. The incubation of cancer cells with CLA showed significant reductions in proliferation (18-100%) compared to control cultures. M21-HPB and MCF-7 cell mortality was dose- and time-dependent. beta-Carotene was inhibitory to breast cells only. MCF-7 cells supplemented with CLA incorporated significantly less [3H]leucine (45%), [3H]uridine (63%) and [3H]thymidine (46%) than control cultures. M21-HPB and HT-29 cells supplemented with CLA incorporated less [3H]leucine (25-30%). These in vitro results suggest that CLA and beta-carotene may be cytotoxic to human cancer cells in vivo.

Differential stimulatory and inhibitory responses of human MCF-7 breast cancer cells to linoleic acid and conjugated linoleic acid in culture.

Consumption of dietary fat has been linked to the high incidence of certain cancers. However, recent research has stimulated interest in conjugated linoleic acid (CLA), a newly recognized anticarcinogenic fatty acid. Human MCF-7 breast cancer cells were incubated for 12 d in culture medium supplemented with various concentrations (1.78-7.14 x 10(-5) M) of linoleic acid (LA) or CLA. Linoleic acid initially stimulated MCF-7 cell growth with an optimal effect at concentrations of 3.57-7.14 x 10(-5) M, but was inhibitory at similar concentrations after 8 and 12 d of incubation. In contrast, CLA was inhibitory to cancer cell growth at all concentrations and times tested. Cell growth inhibition by CLA was dose- and time-dependent. Growth retardation at the prescribed LA and CLA concentrations ranged, respectively, from 4 to 33% and 54 to 100% following 8 to 12 d of treatment. At similar LA and CLA concentrations, cytostatic and cytotoxic effects of CLA were more pronounced (8-81%) than LA. These in vitro results suggest that CLA is cytotoxic to MCF-7 cells.

Effects of lutein from marigold extract on immunity and growth of mammary tumors in mice.

The effects of dietary lutein from marigold extract on the development and growth of a transplantable murine mammary tumor and on lymphocyte function were investigated. Mice were fed a diet containing 0.1% or 0.4% of lutein. In experiment 1, mice were fed the diets for 3 weeks and infused with mammary tumor cells into the mammary gland. Dietary lutein increased tumor latency and inhibited mammary tumor growth in a dose-dependent manner. The incidence of palpable tumors on day 28 post-infusion and final tumor weight were lower in mice fed lutein. In experiment 2, dietary lutein enhanced phytohemagglutinin-induced lymphocyte proliferation but had no effect on interleukin-2 production or lymphocyte cytotoxicity. Therefore dietary lutein increased tumor latency, suppressed mammary tumor growth and enhanced lymphocyte proliferation.

A comparison of the anticancer activities of dietary beta-carotene, canthaxanthin and astaxanthin in mice in vivo.

The anticancer activities of beta-carotene, astaxanthin and canthaxanthin against the growth of mammary tumors were studied in female eight-wk-old BALB/c mice. The mice were fed a synthetic diet containing 0, 0.1 or 0.4% beta-carotene, astaxanthin or canthaxanthin. After 3 weeks, all mice were inoculated with 1 x 10(6) WAZ-2T tumor cells into the mammary fat pad. All animals were killed on 45 d after inoculation with the tumor cells. No carotenoids were detectable in the plasma or tumor tissues of unsupplemented mice. Concentrations of plasma astaxanthin (20 to 28 mumol/L) were greater (P < 0.05) than that of beta-carotene (0.1 to 0.2 mumol/L) and canthaxanthin (3 to 6 mmol/L). However, in tumor tissues, the concentration of canthaxanthin (4.9 to 6.0 nmol/g) was higher than that of beta-carotene (0.2 to 0.5 nmol/g) and astaxanthin (1.2 to 2.7 nmol/g). In general, all three carotenoids decreased mammary tumor volume. Mammary tumor growth inhibition by astaxanthin was dose-dependent and was higher than that of canthaxanthin and beta-carotene. Mice fed 0.4% beta-carotene or canthaxanthin did not show further increases in tumor growth inhibition compared to those fed 0.1% of each carotenoid. Lipid peroxidation activity in tumors was lower (P < 0.05) in mice fed 0.4% astaxanthin, but not in those fed beta-carotene and canthaxanthin. Therefore, beta-carotene, canthaxanthin and especially astaxanthin inhibit the growth of mammary tumors in mice; their anti-tumor activity is also influenced by the supplemental dose.

Effects of conjugated dienoic derivatives of linoleic acid and beta-carotene in modulating lymphocyte and macrophage function.

The in vitro effects of conjugated dienoic derivatives of linoleic acid (CLA) in combination with beta-carotene on lymphocyte and macrophage function was studied. Porcine blood lymphocytes and murine peritoneal macrophages were incubated with 0 (control), 1.78 x 10(-5), 3.57 x 10(-5) and 7.14 x 10(-5) M CLA and 0 (control), 10(-9), 10(-8) and 10(-7) M beta-carotene. CLA alone stimulated mitogen-induced lymphocyte proliferation, lymphocyte cytotoxic activity and macrophage bactericidal activity. In contrast, CLA inhibited interleukin-2 production by lymphocytes and suppressed the phagocytic activity of macrophages. beta-Carotene alone stimulated the cytotoxicity of lymphocytes and increased superoxide production by peritoneal macrophages. When present together, CLA and beta-carotene interacted in an additive manner to further enhance lymphocyte cytotoxicity and spontaneous lymphocyte proliferation. In addition, beta-carotene was able to negate the inhibitory action of CLA on the phagocytic activity of macrophages. Also, CLA and beta-carotene together seemed to suppress mitogen-induced lymphocyte proliferation. Therefore, CLA and beta-carotene; alone and in concert, act to modulate different aspects of cellular host defense.

Dietary beta-carotene and astaxanthin but not canthaxanthin stimulate splenocyte function in mice.

The in vivo modulatory effect of beta-carotene, astaxanthin and canthaxanthin on lymphocyte function was investigated. Female BALB/c mice (8 wk old) were fed a basal diet containing 0, 0.1% or 0.4% beta-carotene, astaxanthin or canthaxanthin for 0, 2 or 4 wk (n = 8/diet/period). Splenic lymphocytes were isolated and mitogen-stimulated proliferation, IL-2 production and lymphocyte cytotoxicity were assessed. Body weight and feed intake were not different among dietary treatments. Plasma carotenoids were undetectable in unsupplemented mice but concentrations of the respective carotenoids were elevated in mice fed 0.1 or 0.4% beta-carotene (0.22 and 0.39 mumol/L), astaxanthin (16.4 and 50.2 mumol/L) and canthaxanthin (5.00 and 7.02 mumol/L) respectively. Mice fed both dietary levels of beta-carotene and astaxanthin had enhanced phytohemagglutinin-induced lymphoblastogenesis compared to unsupplemented mice (P < 0.03). No treatment difference was detected with concanavalin A- or lipopolysaccharide-induced lympho-proliferation nor with IL-2 production (P < 0.05). Astaxanthin (0.1%) also enhanced lymphocyte cytotoxic activity (P < 0.08). In contrast, canthaxanthin did not significantly influence any of the lymphocyte functions measured. Results indicate that beta-carotene and astaxanthin but not canthaxanthin exert enhanced splenic lymphocyte function in mice.

Effects of dietary conjugated linoleic acid on lymphocyte function and growth of mammary tumors in mice.

We studied the effects of conjugated linoleic acid (CLA) on lymphocyte function and growth of a transplantable murine mammary tumor. In experiment 1, eight-wk-old female Balb/c mice (n = 8/group) were fed 0.1%, 0.3% or 0.9% CLA for 3 or 6 wk. Lymphocyte proliferation, interleukin-2 production and lymphocyte cytotoxicity were assessed using splenic lymphocytes. Plasma CLA concentrations increased in a dose-dependent manner with CLA feeding. Lymphocyte proliferation in mice fed 0.3% and 0.9% CLA was enhanced in phytohemagglutinin-induced but not in concanavalin A- or lipopolysaccharide-stimulated cultures. Production of IL-2 also was stimulated by CLA. In contrast, CLA had no effect on lymphocyte cytotoxicity. In experiment 2, mice (n = 20/treatment) were fed the same diets for 2 wk before being infused with 1 x 10(6) WAZ-2T metastatic mammary tumor cells into the right inguinal mammary gland. Tumor volume and latency were recorded for 45 d. Dietary CLA did not affect mammary tumor growth. Tumor latency, tumor incidence and tumor lipid peroxidation activity also were unaffected by CLA. Body weight and feed intake were similar among treatments. Therefore, dietary CLA modulated certain aspects of the immune defense but had no obvious effect on the growth of an established, aggressive mammary tumor.

A standardized gating technique for the generation of flow cytometry data for normal canine and normal feline blood lymphocytes.

Flow cytometry is becoming a commonly used technique to characterize a variety of cells. It provides a powerful application to rapidly determine the relative percentages of T-lymphocyte subsets and B-lymphocytes. The effectiveness of its application, however, is dependent on standardization, especially in a clinical setting. Application of flow cytometry to veterinary diagnostics has been limited by the unavailability of reagents and by the unstandardized characterization of normal values using antibodies not commercially available, but typically provided through the generosity of other researchers. This paper presents a standardized gating protocol, and average values and ranges observed for normal canine and feline blood lymphocytes using commercially available antibodies to cell surface markers for CD5, CD3, CD4, CD8, MHC II, and B lymphocytes. The averages for these markers on gated lymphocytes were as follows: Canine CD5 83.3%, Canine CD4 45.0%, Canine CD8 28.8%, Canine MHC II 98.0%, Canine B Cell 12.9%, Canine CD4/CD8 ratio 1.87, Feline T lymphocytes 77.3%, Feline CD4 44.5%, Feline CD8 25.7%, Feline B Cell 24.1%, Feline CD4/CD8 Ratio 1.75. Normal values were also established for a mixed breed group of dogs, and old versus young dogs. This information will provide researchers and clinicians with a standardized protocol for gating, which establishes a basis for comparison between techniques, and a measure of phenotypic percentages for flow cytometry in normal dogs and cats based on this standardization and commercially available antibodies.

Dietary lutein stimulates immune response in the canine.

The possible immuno-modulatory action of dietary lutein in dogs is not known. Female Beagle dogs (17-18-month old; 11.4+/-0.4kg body weight) were supplemented daily with 0, 5, 10 or 20mg lutein for 12 weeks. Delayed-type hypersensitivity (DTH) response to saline, phytohemagglutinin (PHA) and a polyvalent vaccine was assessed on Weeks 0, 6 and 12. Blood was sampled on Weeks 0, 2, 4, 8 and 12 to assess (1) lymphocyte proliferative response to PHA, concanavalin A (Con A), and pokeweed mitogen (PWM), (2) changes in peripheral blood mononuclear cell (PBMC) populations, (3) interleukin-2 (IL-2) production and (4) IgG and IgM production. After the completion of 12-week study, we continued to collect the blood weekly up to 17 weeks to evaluate the changes in immunoglobulin production upon first and second antigenic challenges on Weeks 13 and 15. Plasma lutein+zeaxanthin was undetectable in unsupplemented dogs but concentrations increased (P<0.05) rapidly on Week 2 in lutein-supplemented dogs. Thereafter, concentrations generally continued to increase in dose-dependent manner, albeit at a much slower rate. Dogs fed lutein had heightened DTH response to PHA and vaccine by Week 6. Dietary lutein increased (P<0.05) lymphocyte proliferative response to all three mitogens and increased the percentages of cells expressing CD5, CD4, CD8 and major histocompatibility complex class II (MHC II) molecules. The production of IgG increased (P<0.05) in lutein-fed dogs after the second antigenic challenge. Lutein did not influence the expression of CD21 lymphocyte marker, plasma IgM or IL-2 production. Therefore, dietary lutein stimulated both cell-mediated and humoral immune responses in the domestic canine.

Modulation of humoral and cell-mediated immune responses by dietary lutein in cats.

The immuno-modulatory role of dietary lutein in domestic cats is unknown. Female Tabby cats (10-month old; n=56) were supplemented daily for 12 weeks with 0, 1, 5 or 10mg lutein. Blood was collected on Weeks 0, 2, 4, 8 and 12 to assess the following: (1) mitogen-induced peripheral blood mononuclear cells (PBMCs) proliferation, (2) changes in PBMC subpopulations, (3) interleukin-2 (IL-2) production and (4) plasma immunoglobulin (Ig)G production. In addition, delayed-type hypersensitivity (DTH) response to concanavalin A (Con A) or a polyvalent vaccine was performed on Weeks 0, 6 and 12. Dietary lutein increased plasma lutein concentrations in a dose-dependent manner (p<0.001) and concentrations had not reached steady state after 12 weeks of feeding in cats given 5 or 10mg lutein. Concentrations of plasma retinol and alpha-tocopherol were not influenced by diet. The DTH response to vaccine but not to Con A increased (p<0.05) in a dose-dependent manner on Week 6. Compared to control, cats fed lutein also showed enhanced Con A- and pokeweed mitogen-stimulated PBMCs proliferation. Dietary lutein also increased the percentages of CD4+ and CD21+ lymphocytes on Week 12 but had no significant effect on pan T, CD8 and MHC class II markers. Plasma IgG was higher (p<0.05) in cats fed 10mg lutein on Weeks 8 and 12. These results support the immuno-modulatory action of lutein in domestic cats.

Effects of blood monocytes and lymphocytes on progesterone secretion by granulosa cells in the pig.

We studied the effects of autologous and nonautologous co-cultures of porcine blood monocytes and lymphocytes with granulosa cells on progesterone secretion. Eight prepubertal crossbred gilts were ovariectomized, and the granulosa cells were collected, plated at 2.5 x 10(5) cells/ml and allowed to attach. Blood was obtained from the same eight gilts, and the mononuclear cells were separated by density gradient centrifugation. Monocytes were separated from lymphocytes by adherence to plastic. Adherent monocytes, lymphocytes and a 1:1 mixture of monocytes + lymphocytes were added to granulosa cell cultures and incubated for 48 h. Progesterone secretion into the media was measured. In addition, blood cell alloreactivity was studied in these co-cultures by measuring uptake of (3)H-thymidine. The co-culture of adherent monocytes or monocytes + lymphocytes with granulosa cells increased (P <.05) progesterone secretion as compared with granulosa cells cultured alone. However, co-culture of lymphocytes with granulosa cells did not have a significant effect. No difference was observed between autologous and nonautologous cell cultures in blood cell proliferation or granulosa cell progesterone secretion. In conclusion, blood monocytes influence progesterone secretion by granulosa cells. In addition, there was no difference in the ability of autologous and nonautologous blood cells to stimulate progesterone secretion by granulosa cells. No alloreactivity was observed using nonautologous immune cells with granulosa cells.

Comparative role of vitamin A and beta-carotene on reproduction and neonate survival in rats.

Female rats were used to investigate the comparative role of vitamin A and beta-carotene (dietary or injected) on growth, feed intake and reproduction. After 3 wk of vitamin A and beta-carotene depletion, rats were assigned to one of six groups: 1) CON = fed 5% NRC recommended level of vitamin A (= 60 mug retinol equivalent (RE)/kg diet); 2) VA = fed 100% of vitamin A (= 1200 mug RE/kg diet); 3) HVA = fed 150% of vitamin A; 4) VA+C = fed 100% of vitamin A + 1.2mg beta-carotene; 5) VA+IC = fed 100% of vitamin A + injected weekly with 8.37 mg of beta-carotene; and 6) VA+IVA = fed 100% of vitamin A + injected weekly with 1400 IU of vitamin A. The level of vitamin A and beta-carotene in dam blood and liver reflected the level of supplementation. No difference in feed intake or body weight was observed. Although mean litter size was similar for all groups, mean pup weight at birth was lowest for deficient rats. Pup mortality through 2 wk postpartum was lower for groups receiving higher levels of either vitamin A or beta-carotene. However, supplemental beta-carotene did not influence growth or reproductive performance. Therefore, low intakes in vitamin A or beta-carotene had no effect on feed intake, growth or reproduction in female rats but decreased fetal growth and increased mortality among pups.

Variables associated with peripartum traits in dairy cows. I. Effect of dietary forages and disorders on voluntary intake of feed, body weight and milk yield.

Daily voluntary intakes of feed by each of 89 Holstein cows were compared between day 220 of gestation and day 30 postpartum over a 21-month period. Diets designed to meet NRC requirements and which contained either chopped hay (29 cows), hay crop silage (HCS; 30 cows) or corn silage (CS; 30 cows) were compared prepartum (27 to 0 days), peripartum (1 day before to 3 days after calving) and postpartum (days 4 to 30 postpartum). Mixed rations, fed during lactation, were 60% forage and 40% concentrate dry matter (DM). Cow management was similar to commercial operations. The experimental hypothesis was that pre-disposition for partum and postpartum disorders (abnormal) could be related either to voluntary intake of different diets or to physical traits. Intakes (DM or estimated net energy) across diets decreased 30% between days 7 and 1 prepartum and averaged 18% and 20% lower peripartum and postpartum, respectively, in abnormal cows than in control cows. Seasonal effects on intakes were significant. In general, changes in body weight and condition and differences in udder edema and milk yield reflected intakes. The results support the original hypothesis.

Variables associated with peripartum traits in dairy cows. II. Interrelationships among disorders and their effects on intake of feed and on reproductive efficiency.

Daily individual voluntary intakes of dry matter (DM % of body weight) and estimated net energy (ENE, Mcal/100 kg) by 89 Holstein cows were compared between day 220 of gestation and day 30 postpartum over a 21-month period. The purpose was to compare effects of diet and health status (control vs. abnormal) on intakes of DM and ENE. The cows were fed either chopped hay, hay crop silage (HCS) or corn silage (CS). Compared to controls, voluntary intakes of DM and ENE were decreased (most to least) in cows with fat cow syndrome (FCS), parturient paresis (PP), mastitis (MST), retained fetal membranes-metritis (RFM-M), and displaced abomasum (DA) prepartum and FCS, DA, PP, RFM-M and MST peripartum. Cows fed hay had a lower incidence of RFM-M (28%) than cows fed HCS (57%) and CS (47%) as well as superior reproductive efficiency subsequently (89% conceived vs. 72% and 78%, respectively).

Effects of supplemental beta-carotene and vitamin A on reproduction in swine.

Since its discovery some 80 yr ago, many advances have been made in understanding the many diverse roles of vitamin A (retinoids). Among these are the critical roles that vitamin A plays in regulating reproduction in both the male and female. The identification of retinol-binding proteins produced by the pig uterus and conceptus marks an exciting event. It will be pivotal to future efforts in elucidating the mechanism by which retinoids regulate conceptus development and steroidogenesis. However, relatively little is known of the possible direct role played by its provitamin, beta-carotene, in controlling reproduction in the pig. However, future research likely will address this aspect of carotenoid function.

Effects of vitamin A and beta-carotene on reproductive performance in gilts.

The effects of vitamin A and beta-carotene on various reproductive parameters were examined in 108 crossbred gilts. Gilts were fed a diet free of vitamin A and beta-carotene for 5 wk, then assigned to one of eight treatments. Statistical comparisons were performed on three sub-groupings of these treatments as follows: (1) DEFICIENT (received 2,100 IU of vitamin A X head-1 X d-1, (2) FED (received dietary supplementation of 0, 2,100 or 12,300 IU vitamin A and (or) 0, 32.6 or 65.2 mg beta-carotene X head-1 X d-1) or (3) INJECTED (received injection supplementation of 0 or 12,300 IU vitamin A and 32.6 mg beta-carotene X head-1 X d-1, administered once weekly). Gilts remained on treatment through weaning of litters at 21 d postpartum. Plasma vitamin A and beta-carotene levels were greatly elevated in INJECTED gilts. Concentrations of these compounds in plasma were similar between DEFICIENT and FED gilts. There was no treatment difference in number of corpora lutea/gilt. Embryonic mortality was lowest (P less than .01 to .02) in INJECTED gilts (14 +/- 3%) compared with DEFICIENT (29 +/- 5%) or FED (25 +/- 3%) gilts. Baby pig mortality averaged 6 +/- 1% and was not different among treatments. INJECTED gilts had more (P less than .05 to .01) piglets/litter at birth and at weaning (9.5 +/- .3 and 9.0 +/- .3 piglets/litter, respectively) than DEFICIENT (7.9 +/- .5 and 7.6 +/- .5 piglets/litter) or FED gilts (8.7 +/- .3 and 8.1 +/- .3 piglets/litter).(ABSTRACT TRUNCATED AT 250 WORDS)

Uptake of orally administered beta-carotene by blood plasma, leukocytes, and lipoproteins in calves.

The uptake of beta-carotene by blood cells, plasma, and lipoproteins was studied in bull calves that were orally administered a single (Exp. 1; n = 18 Angus calves) or multiple (Exp. 2; n = 16 Holstein calves) doses of beta-carotene. Administration of beta-carotene increased plasma beta-carotene and the amount of beta-carotene associated with each lipoprotein fraction. Before beta-carotene treatment, the total amount of beta-carotene associated with the high-density lipoprotein (HDL) was three- to fourfold higher than the amount associated with low-density lipoprotein (LDL) and fivefold higher than the amount associated with very-low-density lipoprotein (VLDL). The relative increase in total beta-carotene associated with the lipoproteins was greater for LDL than for HDL or VLDL. Orally administered beta-carotene increased the uptake of beta-carotene by lymphocytes. Subcellular fractions of blood lymphocytes isolated from animals fed beta-carotene revealed that beta-carotene was taken up in significant amounts by the mitochondrial, nuclear, and microsomal fractions. The profile of beta-carotene uptake by these subcellular fractions did not mirror that observed in plasma. In contrast, beta-carotene was not detectable in blood neutrophils and erythrocytes in either beta-carotene-supplemented or unsupplemented calves. Treatment did not influence the concentrations of retinol or alpha-tocopherol in plasma, lipoproteins, lymphocytes, neutrophils, or erythrocytes. These data revealed the presence of beta-carotene in bovine lymphocyte subcellular fractions and suggest a possible physiological role of beta-carotene in these cells.