Repletion Phase Research Articles

The lower content of mineral-complexing compounds favored the in vitro and in vivo iron bioavailability of biofortified cowpeas

This study aimed to evaluate in vitro and in vivo iron bioavailability of biofortified cowpeas (Vigna unguiculata (L) Walp) (Aracê, Xiquexique and Tumucumaque), compared to a conventional cultivar (Pajeú). In vitro bioavailability was evaluated in Caco-2 cells. For the in vivo study, 40 male Wistar rats were induced to anemia during 21 days (depletion phase), then, in repletion phase (14 days), the animals received as iron source (12 ppm): ferrous sulfate; Pajeú; Xiquexique, Aracê; or Tumucumaque. Pajeú had higher levels of complexing compounds than the biofortified cultivars. In Caco-2 cells, the cellular iron uptake index was higher for biofortified cowpeas, particularly Tumucumaque. Concerning the in vivo study, Tumucumaque group had the best hemoglobin regeneration efficiency and relative biological value, and improved colon crypt size. Then, the iron bioavailability was higher in the biofortified cowpeas, especially Tumucumaque, possibly due to the lower content of mineral-complexing compounds and improvement of absorptive area. This work provides important information to support strategies to combat iron deficiency.

Development of the mineralisation of individual bones and bone regions in replacement gilts according to dietary calcium and phosphorus

Skeleton bones, distinguished by trabecular and cortical bone tissue content, exhibit varied growth and composition, in response to modified dietary calcium and phosphorus levels. The study investigated how gilts adapt their individual bone and bone region mineralisation kinetics in response to changing intake of Ca and P. A total of 24 gilts were fed according to a two-phase (Depletion (D) 60–95 and Repletion (R) 95–140 kg BW, respectively). During the D phase, gilts were fed either 60% (D60) or 100% (D100) of the estimated P requirement. Subsequently, during the R phase, half of the gilts from each D diet were fed either 100% (R100) or 160% (R160) of the estimated P requirement according to a 2 × 2 factorial arrangement. Bone mineral content (BMC) was assessed in the whole body, individual bones (femur and lumbar spine L2–L4), and bone regions (head, front legs, trunk, pelvis, femur, and hind legs) every 2 weeks using dual-energy X-ray absorptiometry (DXA). At 95 kg BW, gilts fed D60 showed reduced BMC and BMC/BW ratio in all studied sites compared to those fed D100 (P < 0.001). During the depletion phase, the allometric BW-dependent regressions slopes for BMC of D100 gilts remained close to 1 for all sites and did not differ from each other. In contrast, the slopes were lower in D60 gilts (P < 0.05), with an 18% reduction in the whole body, except for the front and hind legs, femur, and pelvis, which exhibited higher reductions (P < 0.05). At 140 kg BW, BMC and BMC/BW ratio of all studied sites were similar in gilts previously fed D60 and D100, but higher in R160 than in R100 gilts (P < 0.05), except for front and hind legs. During the repletion phase, the allometric BW dependent regressions slopes for BMC were lower (P < 0.05) in R100 than in R160 gilts (for whole body −10%; P < 0.01) except for front and hind legs, femur, and pelvis. In conclusion, bone demineralisation and recovery followed similar trends for all measured body sites. However, the lumbar spine region was most sensitive whereas the hind legs were least sensitive. These data suggest that using bone regions such as the head and forelegs that can be collected easily at the slaughterhouse may be a viable alternative to whole body DXA measurement.

Dynamic responses of blood metabolites to nutrient depletion and repletion in broiler chicken nutrition

A total of 720 male Cobb 500 broiler chicks were used in a 5 treatment and 8 replicate experiment to explore dynamic changes in blood metabolites in response to short-term nutrient depletion and repletion. Day old chicks were offered a corn and soybean meal-based common starter diet from d1 to 14 that was formulated to meet all nutrient requirements of the birds. From d15 to 17, the experimental diets were offered, before returning all groups to a common diet from d18 to 20, at which point the experiment was terminated. A total of 5 experimental diets were designed. A standard grower diet served as a control and was offered to 1 of the 5 groups of chicks. The additional 4 experimental groups comprised diets that were low in digestible phosphorus (P), total calcium (Ca), crude protein and digestible amino acids (AA) or apparent metabolizable energy (AME). The common grower diet that was offered from d18-20 was designed to be nutritionally complete and was intended to explore dynamic response to nutrient repletion. Blood was drawn from 8 chicks per treatment at time 0 (immediately prior to introduction of the experimental diets) and then again 3, 6, 12, 24, and 48h after introduction of the nutrient depleted diets. Additionally, blood was drawn 3, 6, 12, 24, and 48h after the introduction of the nutritionally complete common grower diet. Chicks were not sampled more than once. Feed intake, body weight and feed conversion ratio (FCR) were assessed on d14, 17, and 20. Blood metabolites were analyzed using the iSTAT Alinity V handheld blood analyzer, the Vetscan VS2 Chemistry Analyzer and the iCheck Carotene Photometer. Live performance metrics were not affected by the short-term nutrient depletion and all chicks grew normally throughout the experiment. The diet with low digestible P generated a rapid temporary decrease in plasma P and an increase in plasma Ca, that were returned to baseline following the re-introduction of the common grower feed. Introduction of the diet with low total Ca resulted in a significant increase in plasma P, effects which were also mitigated during the nutrient repletion phase. Total plasma protein, albumin and uric acid (UA) were decreased, and plasma glucose increased, in the chicks that received the diet with low crude protein and digestible AA. There was a delayed increase in aspartate amino transaminase (AST) associated with the diets with low digestible P and low AME. These results demonstrate the capacity of blood biochemistry to adapt to quantitative and qualitative changes in nutrient intake. Point-of-care analysis of blood biomarkers offers nutritionists a valuable opportunity to calibrate nutritional matrices for common dietary ingredients, zootechnical feed additives and to optimize diet phase changes. It can be concluded that many blood biomarkers are plastic to changes in diet nutrient density and offer an objective index for optimization of nutritional programs for commercial broiler production.

Impact of deoxynivalenol in a calcium depletion and repletion nutritional strategy in piglets.

This study evaluated the effect of dietary calcium (Ca) levels and deoxynivalenol (DON) contamination on Ca and phosphorus (P) utilization and bone mineralization in piglets. During an initial 13-d depletion phase, 64 piglets (15.7 ± 0.7kg) received a control (DON-) or DON-contaminated treatment (DON+, 2.7mg DON/kg) with either a low Ca (Ca-, 0.39%) or normal Ca level (Ca+, 0.65%) with a constant digestible P level (0.40%). A second group of 16 piglets received DON- or DON+ treatments for 9 d for gene expression analysis. During the subsequent 14-d repletion phase, all piglets were fed a Ca+ DON- diet containing 0.65% Ca and 0.35% digestible P without DON. After 5 d of the depletion phase, the absorption of P (DON × Ca; P < 0.05) and Ca was increased by the Ca- (P < 0.01) and DON+ (P < 0.01) diet. After 13 d, feed conversion ratio (P < 0.01) and average daily feed intake (P = 0.06) tended to decrease with the Ca- diet. The bone mineral content (BMC) gain was decreased by Ca, especially with Ca- DON + (DON × Ca, P < 0.05). The P absorption was increased by Ca- DON + (DON × Ca, P < 0.01), although the P retention efficiency was only increased by Ca+ DON + (DON × Ca, P < 0.001). The absorption of Ca was increased by DON+ (P < 0.001), and the Ca efficiency was increased by Ca- DON- (DON × Ca, P < 0.01). After 9 d, the gene expression of intestinal claudin 12 (P < 0.01) and CYP24A1 (P < 0.05), femur cortical RANKL (P < 0.05) and OPG (P = 0.06), and renal calbindin D9K (P < 0.05) and Klotho (P = 0.07) were decreased by DON+. The Ca (P = 0.06) and magnesium (P < 0.01) concentrations were decreased by DON+, and the Ca (P = 0.06) and P digestibility (P < 0.01) were increased. After the repletion phase, Ca- piglets recovered their BMC deficit, but not those receiving DON+ (DON × Ca; P = 0.06). The Ca (P < 0.05) and P (P = 0.06) retention efficiency tended to increase with Ca-. The absorption of Ca and P was increased by Ca- and DON+ (DON × Ca, P < 0.05). The results show that piglets increased their Ca and P utilization efficiency, allowing them to recover the BMC deficit caused by Ca-, but not when the piglets were exposed to DON. Pigs previously receiving Ca-deficient diet with DON still have lower body Ca and P, leading to elevated calcitriol concentrations and enhanced Ca and P intestinal absorption. The fact that DON decreased the expression of genes implicated in Ca intestinal and renal transport and P excretion after 9 d can potentially explain the reduced plasma Ca concentration.

Nanoplanktonic diatom rapidly alters sinking velocity via regulating lipid content and composition in response to changing nutrient concentrations

Diatom sinking plays a crucial role in the global carbon cycle, accounting for approximately 40% of marine particulate organic carbon export. While oceanic models typically represent diatoms as microphytoplankton (&amp;gt; 20 μm), it is important to recognize that many diatoms fall into the categories of nanophytoplankton (2-20 μm) and picophytoplankton (&amp;lt; 2 μm). These smaller diatoms have also been found to significantly contribute to carbon export. However, our understanding of their sinking behavior and buoyancy regulation mechanisms remains limited. In this study, we investigate the sinking behavior of a nanoplanktonic diatom, Phaeodactylum tricornutum (P. tricornutum), which exhibits rapid changes in sinking behavior in response to varying nutrient concentrations. Our results demonstrate that a higher sinking rate is observed under phosphate limitation and depletion. Notably, in phosphate depletion, the sinking rate of P. tricornutum was 0.79 ± 0.03 m d-1, nearly three times that of the previously reported sinking rates for Skeletonema costatum, Ditylum brightwellii, and Chaetoceros gracile. Furthermore, during the first 6 h of phosphate spike, the sinking rate of P. tricornutum remained consistently high. After 12 h of phosphate spike, the sinking rate decreased to match that of the phosphate repletion phase, only to increase again over the next 12 hours due to phosphate depletion. This rapid sinking behavior contributes to carbon export and potentially allows diatoms to exploit nutrient-rich patches when encountering increased nutrient concentrations. We also observed a significant positive correlation (P&amp;lt; 0.001) between sinking rate and lipid content (R = 0.91) during the phosphate depletion and spike experiment. It appears that P. tricornutum regulates its sinking rate by increasing intracellular lipid content, particularly digalactosyldiacylglycerol, hexosyl ceramide, monogalactosyldiacylglycerol, and triglycerides. Additionally, P. tricornutum replaces phospholipids with more dense membrane sulfolipids, such as sulfoquinovosyldiacylglycerol under phosphate shortage. These findings shed light on the intricate relationship between nutrient availability, sinking behavior, and lipid composition in diatoms, providing insights into their adaptive strategies for carbon export and nutrient utilization.

Maternal Energy Depletion Is Buffered among Malnourished Women in Punjab, Pakistan ,

Women's nutritional status is believed to deteriorate with increasing reproductive stress (so-called maternal depletion). To evaluate this phenomenon, a new theoretical framework has been suggested that incorporates the concepts of a full reproductive cycle, relative lengths of potential depletion and repletion phases, and initial plane of nutrition. We developed the corresponding statistical model and tested predictions provided by the framework about the effect of reproductive pattern on maternal overall weight change (deltaW) during one reproductive cycle. Seventy-six Pakistani women were classified as well-nourished, marginally nourished or malnourished. The relationship between deltaW and length of all phases of the reproductive cycle, each of which is characterized by varying degrees of reproductive stress, was evaluated with multiple regression analysis. Across the reproductive cycle, well-nourished women had a slight weight increase. Surprisingly, malnourished women gained weight in contrast to marginally nourished women. Also surprisingly, for the latter two groups, periods of moderate reproductive stress were associated with weight loss but periods of high reproductive stress were associated with weight gain. Mechanisms such as efficiency and nutrient partitioning are discussed.

Iron-induced NCOA4 condensation regulates ferritin fate and iron homeostasis.

Iron is not only essential but also a toxic trace element. Under iron repletion, ferritin maintains cellular iron homeostasis by storing iron to avoid iron toxicity. Under iron depletion, the ferritin-specific autophagy adaptor NCOA4 delivers ferritin to lysosomes via macroautophagy to enable cells to use stored iron. Here, we show that NCOA4 also plays crucial roles in the regulation of ferritin fate under iron repletion. NCOA4 forms insoluble condensates via multivalent interactions generated by the binding of iron to its intrinsically disordered region. This sequesters NCOA4 away from ferritin and allows ferritin accumulation in the early phase of iron repletion. Under prolonged iron repletion, NCOA4 condensates can deliver ferritin to lysosomes via a TAX1BP1-dependent non-canonical autophagy pathway, thereby preventing relative iron deficiency due to excessive iron storage and reduced iron uptake. Together, these observations suggest that the NCOA4-ferritin axis modulates intracellular iron homeostasis in accordance with cellular iron availability.

Immune Regulatory Cell Bias Following Alemtuzumab Treatment in Relapsing-Remitting Multiple Sclerosis.

Alemtuzumab is a highly effective treatment for relapsing-remitting multiple sclerosis. It selectively targets the CD52 antigen to induce profound lymphocyte depletion, followed by recovery of T and B cells with regulatory phenotypes. We previously showed that regulatory T cell function is restored with cellular repletion, but little is known about the functional capacity of regulatory B-cells and peripheral blood monocytes during the repletion phase. In this study (ClinicalTrials.gov ID# NCT03647722) we simultaneously analyzed the change in composition and function of both regulatory lymphocyte populations and distinct monocyte subsets in cross-sectional cohorts of MS patients prior to or 6, 12, 18, 24 or 36 months after their first course of alemtuzumab treatment. We found that the absolute number and percentage of cells with a regulatory B cell phenotype were significantly higher after treatment and were positivity correlated with regulatory T cells. In addition, B cells from treated patients secreted higher levels of IL-10 and BDNF, and inhibited the proliferation of autologous CD4+CD25- T cell targets. Though there was little change in monocytes populations overall, following the second annual course of treatment, CD14+ monocytes had a significantly increased anti-inflammatory bias in cytokine secretion patterns. These results confirmed that the immune system in alemtuzumab-treated patients is altered in favor of a regulatory milieu that involves expansion and increased functionality of multiple regulatory populations including B cells, T cells and monocytes. Here, we showed for the first time that functionally competent regulatory B cells re-appear with similar kinetics to that of regulatory T-cells, whereas the change in anti-inflammatory bias of monocytes does not occur until after the second treatment course. These findings justify future studies of all regulatory cell types following alemtuzumab treatment to reveal further insights into mechanisms of drug action, and to identify key immunological predictors of durable clinical efficacy in alemtuzumab-treated patients.

193 Evaluation of copper and selenium metabolism in Bos indicus and Bos taurus cows

Abstract A two-year study was conducted to evaluate the differences in metabolism of Cu and Se among Bos indicus and Bos taurus cows. Thirty-two pregnant cows were enrolled in the study (n = 16/ year; 8 Brahman and 8 Black Angus). Cows were randomly assigned to individual pens at the beginning of the study, which was divided in 3 phases: depletion, repletion and calving. Throughout the study cows were fed grain supplement and had access to hay. During the depletion phase grain supplement was enriched with S (50g/head daily) to promote a decline in Cu and Se status. During the repletion phase, the extra S was removed from the grain supplement and Cu (100 mg/head daily) and Se were added (3 mg/head daily). To evaluate the mineral status, liver samples were collected from cows every 30 days and from calves at birth. Initial data was evaluated using the PROC MIXED procedure of SAS. No treatment effects (P = 0.14) were observed for liver Cu concentration, excepted for a day effect (P ≤ 0.01) as expected by the study design. Although there was a treatment x year interaction (P ≤ 0.01) for liver Se concentration a tendency for treatment (P = 0.10) was observed, where Angus cows tended to have greater liver Se concentration than Brahman cows (0.81 and 0.71 mg/kg; SEM = 0.048). No differences (P = 0.71) were observed for calf liver Cu (265 and 345 mg/kg; SEM = 94; respectively for Angus and Brahman) and Se (1.13 and 1.07 mg/kg; SEM = 0.11; respectively for Angus and Brahman) concentrations at birth. Similarly, no differences (P = 0.39) were observed for cotyledon Cu (7.7 and 6.0 mg/kg; SEM = 1.02; respectively for Angus and Brahman) and Se (0.74 and 0.77 mg/kg; SEM = 0.06; respectively for Angus and Brahman) concentrations.

Fortifying pork liver mixture: Evaluation of protein quality and iron bioavailability – Part 2

ABSTRACT Objective To evaluate the protein quality and iron bioavailability of a fortifying mixture based on pork liver. Methods Determinations of protein efficiency ratio, net protein utilization, true digestibility and hemoglobin regeneration efficiency by depletion and repletion were performed. In the depletion phase, the animals (male Wistar rats) received an iron-free AIN–93G diet and in the repletion phase they received the following diets: standard AIN–93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate for comparison. Results For standard AIN–93G diet and fortifying mixture the results were 3.75 and 4.04 for protein efficiency ratio and 3.53 and 3.63 for net protein retention, showing that the presence of pork liver in the diet promoted an increase in protein efficiency ratio and net protein retention (not statistically significant). True digestibility results obtained with the fortifying mixture (97.16%) were higher than those obtained with the standard AIN–93G diet (casein), but without significant difference. The hemoglobin regeneration efficiency values obtained for standard AIN–93G diet, fortifying mixture and standard diet containing heptahydrated ferrous sulfate were 50.69, 31.96 and 29.96%, respectively, showing a statistically significant difference between the control (standard AIN–93G diet) and test (fortifying mixture and standard diet containing heptahydrated ferrous sulfate) samples, but not between the test samples. Conclusion The fortifying mixture showed a high protein efficiency ratio value of 4.04 and a high relative biological value (108%) and it can be added to soups, creams and meats in day-care centers for the prevention of iron-deficiency in children of school age.

Vitamin A deficiency in Bos indicus heifers fed a wheat straw diet cannot be corrected with algae lick blocks or intramuscular injectable retinyl palmitate treatments

Serum and liver retinol concentrations and blood β-carotene concentrations were studied in 30 Bos indicus heifers rendered deficient of vitamin A over 180 days and then given treatments of access to algae-based lick blocks (n = 10), injectable retinyl palmitate and molasses-based lick blocks (n = 10), or a negative control given access to molasses-based lick blocks only (n = 10). All heifers became deficient in blood and liver vitamin A, as well as blood β-carotene by 180 days. There was no treatment effect on bodyweight (P = 0.347). However, a highly significant effect of time (P = 0.001) was detected where all heifers achieved an average daily gain of 0.74 kg/day throughout the depletion phase of the study but lost 0.150 kg/day during the repletion phase. The concentrations of serum and liver retinol and blood β-carotene were not different between treatment groups (P = 0.362, P = 0.535 and P = 0.839) during the depletion or repletion phases of the study. All heifers continued to be rendered deficient in the concentrations of serum and liver retinol and blood β-carotene throughout the experiment demonstrating a highly significant effect of time (P = 0.001). Injectable retinyl palmitate (818 100 IU retinol) or access to algal lick blocks (4180 IU retinol) did not elevate blood or liver retinol concentrations in heifers rendered deficient of vitamin A. It is speculated that the protein-deficient diet fed to the heifers had an adverse effect on the blood retinol transport proteins.

Influence of feeding a low-phosphorus diet on leucocyte function in dairy cows

Phosphorus depletion and hypophosphatemia have been described to interfere with immune function in rats and humans. In dairy cows, hypophosphatemia has been associated with muscle weakness and recumbency as well as with intravascular hemolysis resulting from increased osmotic fragility of erythrocytes, but so far, the influence of P depletion and hypophosphatemia on immune function has not been studied. Therefore, the aim of this study was to investigate whether P depletion and ensuing hypophosphatemia are associated with impaired granulocyte and lymphocyte function. Eight mid-lactation dairy cows were fed a P-deficient ration (0.2% P/kg of DM) for a period of 4wk. The depletion phase was preceded by a 2-wk acclimatization period and followed by a 2-wk repletion phase, during which the same ration was supplemented with P to meet or exceed daily requirements. Blood samples were collected at the end of the acclimatization period, after 2 and 4wk of P depletion, and at the end of the repletion phase. Plasma phosphate concentrations ([Pi]) were determined and white blood cells were counted and isolated. General immune function was investigated by performing a phagocytosis assay with Staphylococcus aureus and a lymphocyte stimulation test (LST) with concanavalin A and pokeweed mitogen. The plasma [Pi] decreased significantly, with the lowest values (mean 0.7±0.2mmol/L) occurring after 2wk of depletion, although depletion was continued for another 2wk. During repletion, plasma [Pi] increased above baseline concentrations. Granulocyte counts changed in parallel with plasma [Pi] over time, decreasing significantly at 2wk after P depletion and increasing again thereafter. Granulocyte survival after phagocytosis was lowest after 4wk of P depletion. Phagocytosis activity of surviving granulocytes determined by mean fluorescence intensity was higher, indicating that phagocytosis was not negatively influenced by P depletion. Lymphocyte stimulation showed a similar trend, with a decreasing stimulation index at the end of P depletion, but differences were not statistically significant. Data presented in this study indicate that hypophosphatemia leads to a decrease in granulocyte counts. Chronic P depletion impairs granulocyte survival during phagocytosis but not phagocytosis activity. Lymphocyte function is not influenced by P depletion.

Intake of butter naturally enriched with cis9,trans11 conjugated linoleic acid reduces systemic inflammatory mediators in healthy young adults

A conjugated linoleic acid (CLA) depletion–repletion study was carried out to investigate the effects of dietary c9,t11 CLA on C-reactive protein, transcription factor NFκB, metalloproteinases 2 and 9, inflammatory mediators (adiponectin, TNFα, IL-2, IL-4, IL-8, IL-10), body composition, and erythrocyte membrane composition in healthy normal-weight human adults. CLA depletion was achieved through an 8-week period of restricted dairy fat intake (depletion phase; CLA intake was 5.2±5.8 mg/day), followed by an 8-week period in which individuals consumed 20 g/day of butter naturally enriched with c9,t11 CLA (repletion phase; CLA intake of 1020±167 mg/day). The participants were 29 healthy adult volunteers (19 women and 10 men, aged 22 to 36 years), with body mass index between 18.0 and 29.9 kg m−2. Blood samples were collected at baseline and at the end of both depletion and repletion phases. The content of CLA in erythrocytes decreased during CLA-depletion and increased during CLA-repletion. Intake of CLA-enriched butter increased the serum levels of anti-inflammatory IL-10 but reduced transcription factor NFκB in blood and serum levels of TNFα, IL-2, IL-8 and inactive metalloproteinase-9. Moreover, reduced activity of metalloproteinases 2 and 9 in serum was observed during the CLA-repletion period. In contrast, intake of CLA-enriched butter had no effects on body composition (DXA analysis) as well as on serum levels of adiponectin, C-reactive protein, and IL-4. Taken together, our results indicate that the intake of a c9,t11 CLA-enriched butter by normal-weight subjects induces beneficial changes in immune modulators associated with sub-clinical inflammation in overweight individuals.

The effect of selenium supplementation on vaccination response and immune function in adult horses1

Selenium status has been reported to affect immune function across many different species. Yet few studies have focused on the effect of Se status on the equine immune system. This study examined the effect of Se supplementation on vaccination response and immune function in mature horses. Twenty-eight horses were blocked by age and sex and were randomly allocated to 1 of 4 dietary treatment groups: low Se (LS), adequate Se (AS), Se-yeast (SP), and sodium selenite (SS). For 35 wk, horses allocated to LS, SP, and SS received a low-Se diet (0.06 mg/kg DM) with the intention to lower Se stores, whereas AS received an adequate Se diet (0.12 mg/kg DM). A 29-wk repletion phase was as follows: LS and AS were kept on the diets fed during the depletion period, whereas SP and SS received the depletion diet plus their respective Se supplements to achieve a dietary Se concentration of 0.3 mg/kg DM. The Se status of the horses was monitored using whole blood Se and glutathione peroxidase (GSH-Px) activity as indicators. At wk 22 and 25 of the repletion phase, horses were vaccinated intramuscularly with 10 mg ovalbumin (OVA). Horses were also vaccinated against equine influenza at wk 25. Blood samples were collected for 7 wk after initial vaccination for serum separation and at 0, 3, and 5 wk postvaccination for peripheral blood mononuclear cell (PBMC) isolation and whole blood cytokine mRNA evaluation. At wk 22 of the repletion phase, both Se and GSH-Px were greater for SP and SS compared with AS and LS (P < 0.001). Serum vitamin E was similar between treatments. Response to OVA vaccination, evaluated as OVA-specific IgG production, cytokine mRNA expression of PBMC stimulated with OVA in vitro, and lymphocyte proliferation, was unaffected by Se status. Similarly, memory response to the influenza vaccine was not affected by Se status. However, decreased mRNA expression of selected cytokines was observed in PBMC stimulated with phorbol 12-myristate 13-acetate for LS compared with AS, SP, and SS (P < 0.05). Whole blood mRNA expression of IL-10 was greater for SS compared with LS, AS, and SP (P = 0.043). Although the OVA and influenza vaccination responses were unaffected by Se status, other measures of immune function did indicate that low Se status could adversely affect cell-mediated immunity.

Interrelationships among selenium status, antioxidant capacity and oxidative stress in the horse

Interrelationships among selenium status, antioxidant capacity and oxidative stress in the horse

Fatty acid composition of erythrocytes reflects CLA intake in a depletion‐repletion study with healthy subjects

We studied fatty acid (FA) composition of erythrocytes in response to CLA depletion (8 w) and CLA repletion (8 w), in 27 men and women, aged 23 to 36 years. During the depletion phase all participants excluded sources of dairy fat from their diets and in the repletion phase they returned to their habitual diets and received 20 g of CLA‐biofortified butter, resulting in the intake of 1 g CLA/d. The FA composition of erythrocytes was determined by GC after lipid extraction and FA transesterification. Twenty‐seven FA were detected in the erythrocytes. The CLA contents (g/100g FA) in erythrocytes decreased significantly (p&lt;0.01) in the depletion phase (0.18±0.03) when compared to baseline (0.31±0.05) and increased in the repletion phase (0.34±0.06). In addition, the CLA contents in erythrocytes were positively correlated with the habitual intake of CLA food sources obtained from a food‐frequency questionnaire. The ratio between 20:4n‐6 and 20:3 n‐6 was used as indicator of Δ5‐desaturase activity and reduced (p&lt;0.05) in the CLA repletion phase. In addition, arachidonic acid was negatively correlated (r= 0.49; p&lt;0.05) with CLA in erythrocytes. Our results are suggestive of erythrocyte composition as marker of CLA intake and of effects of CLA on Δ5‐desaturase activity, which could mediate some of the observed biological effects of CLA.Grant Funding Source: FAPERJ, CAPES, CNPq (Brazil).

Dermal Carotenoids as Measured by Resonance Raman Spectroscopy as a Biomarker of Response to a Fruit/Vegetable Intervention Study

Dermal carotenoid status may have utility as a biomarker for vegetable and fruit consumption. Resonance Raman spectroscopy (RRS) is a valid, non‐invasive method to assess dermal carotenoids as a biomarker of usual vegetable and fruit intake, but has not been evaluated in response to a whole‐diet intervention. Thirteen outpatient subjects who reported a mean intake of 16 mg total carotenoids/day followed a depletion diet (0.76 mg/d) for 6 weeks, and then consumed a controlled repletion diet based upon the Dietary Guidelines for Americans that contained an average of 62 mg carotenoid/d for 8 weeks. RRS measures of the palm were taken at least 2x week during depletion and 5x week during the repletion phase. To model depletion and repletion, the Glimmix procedure in SAS was used and included a linear term for the depletion phase, linear and quadratic terms for the repletion phase, and subject as a random effect. Subjects’ RRS scores decreased by 35 ±12.5% (p&lt;0.001) during depletion and increased by 380 ±180.0% (p&lt;0.001) during repletion. Depletion and repletion slopes did not differ between subjects (p&gt;0.55), despite there being a broad range of baseline values (49% CV). No subject achieved a maximal value during the 8‐week repletion period. RRS is a non‐invasive method that shows great promise as an objective biomarker of response to changes in consumption of carotenoid‐rich foods by individuals.

Protein deficiency, but not zinc deficiency, reduces recovery of type 1 and type 2 muscle fibre diameters in the gastrocnemius muscle of growing rats

The present study examines the effects of protein- and energy-type malnutrition in combination with Zn deficiency on the growth, serum insulin-like growth factor-1 (IGF-1), gastrocnemius muscle mass and fibre diameter of growing rats during a deficiency phase followed by nutritional rehabilitation. Rats (3-weeks old) were randomly assigned to baseline, or Zn-deficient (Z, < 1 mg Zn/kg), protein-deficient (P, 20 g protein/kg), combined Zn- and protein-deficient (ZP), energy-deficient (E, feed intake pair-fed to Z) or control (C, 30 mg Zn/kg and 170 g protein/kg) groups for a 3-week deficiency phase, followed by a 3-week repletion phase with the control diet. ATPase histochemical staining at pH 9·4 was used to differentiate type 1 and type 2 muscle fibres. After the deficiency phase, the ZP and P groups had lower body weight and smaller gastrocnemius muscle mass than the Z and E groups. Type 1 and 2 muscle fibre diameters (T1- and T2-MFD, respectively) were reduced in the ZP, P and Z groups compared with the E and C groups. Serum Zn was reduced in the ZP, P and Z groups, but serum IGF-1 was lowest in the Z and E groups. After the repletion phase, T1-MFD did not recover in the P and E groups nor T2-MFD in the P group, despite the P and E groups having a better recovery of body weight. In summary, previous protein deficiency, but not Zn deficiency, limited the recovery of both T1- and T2-MFD during nutritional repletion. The quality of skeletal muscle recovery in the malnourished groups was not associated with body weight, muscle mass, serum Zn or IGF-1 concentrations.

Long-Term Marginal Zinc Supply Is Not Detrimental to the Skeleton of Aged Female Rats

In this experiment, we investigated the long-term effects of a marginal zinc (Zn) supply on bone metabolism in aged rats. Nine-mo-old female Fischer-344 rats were divided into 8 weight-matched groups of 8 rats each. All rats were adapted for 1 mo to restrictive feeding (7.5 g/d) of a purified diet containing 8 g/kg sodium phytate and 64 mg/kg Zn. Control rats were pair-fed throughout the experiment. During the 1-mo depletion phase, controls received the Zn-replete diet with 64 mg/kg Zn, whereas Zn-deficient rats were fed the same diet with 2.2 mg/kg Zn. The depletion phase was followed by a 3-mo marginal phase in which the rats fed the diet with 2.2 mg/kg Zn received an additional daily Zn supplement of 75 μg Zn/rat by gavage. In the following 2-mo repletion phase, a marginal group was switched to the Zn-replete diet, while the other groups were maintained on marginal Zn supply or on the Zn-replete diet. Zn depletion and marginal Zn reduced serum and bone Zn and serum alkaline phosphatase activity. Zn repletion normalized serum Zn. However, apart from subtle changes in bone mineralization density distribution, Zn deficiency was not associated with detrimental effects on bone mineral density, turnover, architecture, or biomechanics relative to control rats at any time point. Our data suggest that Zn does not play an essential role in bone metabolism in aged rats and cast doubt on the hypthosis that Zn deficiency is a risk factor for osteoporosis.

Repletion of glycogen in muscle is preceded by repletion of glycogen in the liver of Merino hoggets

An experiment was conducted using 105 Merino hoggets to measure the change in tissue glycogen concentration over a 48-h period following an exercise regime. The exercise regime consisted of a 2-km run repeated four times with a 15-min break between each run. After exercise the hoggets were split into treatment groups and fed three different levels (fasting, maintenance and three times maintenance) of the same ration. A subset of each group of hoggets was killed at –24, 0, 12, 24 and 48 h from the time of exercise and samples taken from the liver, skin, rumen, duodenum, colon, kidney, M. semimembranosus, M. semitendinosus, M. longissimus thoracis et lumborum, M. psoas major, M. triceps brachii and M. subscapularis. Exercise caused a reduction in glycogen concentration in the liver and all muscles but not in the kidney, skin, duodenum, or colon tissues. After exercise the most significant changes in glycogen concentration were in the liver, muscle and skin. Metabolisable energy intake influenced the change in the liver and muscle tissue but not in the skin. It was concluded that glycogen concentration increased in liver before muscle and that this effect may contribute to the slower rate of glycogen concentration in muscle for ruminants compared with monogastric animals. Skin may also compete with muscle for glucose during the repletion phase in Merino sheep but the exact nature of this effect remains uncertain.