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Vitamin A, vitamin E and retinol-binding protein 4 (RBP4) are a focus of current obesity research in humans. The impact of body weight (BW) gain on fat-soluble vitamins and its associated parameters in equines has not been previously reported. Ten Shetland ponies and 9 Warmblood horses, all adult geldings, non-obese and healthy, were fed an excessive energy diet for 20 months to induce BW gain. Serum alpha-tocopherol (vitamin E), retinol (vitamin A), retinol-binding protein 4 (RBP4) and retinol/RBP4 ratio were analysed before BW gain induction and at six timepoints during the BW gaining period. The mean (+/- SD) % BW gain achieved during two years of excess energy intake was 29.9 +/- 19.4% for ponies and 17 +/- 6.74% for horses. Serum alpha-tocopherol increased significantly in ponies and horses during excess energy intake and circulating alpha-tocopherol levels correlated positively with alpha-tocopherol intake (r = .6; p < .001). Serum retinol concentrations showed variations during the study but without relation to intake. Serum RBP4 decreased at the end of the study. The retinol/RBP4 ratio increased with BW gain without differences between ponies and horses. In comparison with human research, the increase in the retinol/RBP4 ratio was unexpected and needs further elucidation.
Extra-cellular matrix (ECM) components are important and their stabilization is significant in maintaining normal healthy joint environment. In osteoarthritis (OA), ECM components are altered and indicate disease progression. The joint ECM is composed of proteoglycans (aggrecan, perlecan,inter α-trypsin inhibitor), glycoproteins (fibronectin, lubricin, COMP) and collagen types (most abundantly collagen type II) which represent structural and functional transformation during disease advancement. ECM investigation revealed significant biomarkers of OA that could be used as a diagnostic and therapeutic tool in different canine orthopedic diseases. This review deliberates our current findings of how the components of ECM change at the molecular level during disease progression in canine OA.
To study the role of the TTR-RBP4-ROH complex components (transthyretin, serum retinol binding protein, retinol) and of angiogenic factors PlGF (placental growth factor) and sFlt-1 (soluble fms-like tyrosine kinase-1) in pregnancies complicated by small for gestational age infants (SGA). Case control study conducted on maternal serum collected between 11 + 0 to 13 + 6 weeks of gestation. TTR, RBP4, ROH, PlGF and sFlt-1 were measured in SGA patients (birth weight < 10%) who delivered at term (n = 37) and before 37 weeks of gestation (n = 17) and in a matched control group with uneventful pregnancies (n = 37). We found decreased RBP4 in SGA patients that delivered fetuses < 3% and in fetuses delivered after the 37 weeks of gestation compared to controls [1.50 (95% CI 1.40-1.75) vs 1.62 (95% CI 1.47-1.98), p < 0.05]. Further, we found lower PlGF and sFlt-1 concentrations in SGA that delivered before 37 weeks of gestation compared to controls (respectively, PIGF and sFlt-1: 39.7 pg/ml (95% CI 32.3-66.3) vs 62.9 pg/ml (95% CI 45.2-78.4) and 906 pg/ml (95% CI 727-1626) vs 1610 pg/ml (95% CI 1088-212), p < 0.05). First trimester maternal serum RBP4 and angiogenic factors PlGF and sFlt-1 can differently predict the timing of delivery of pregnancies complicated by SGA fetuses.
Obesity is a key component of equine metabolic syndrome, which is highly associated with laminitis. Feed restriction and/or exercise are known to alleviate the detrimental effects of insulin resistance in obese ponies. However, little is known about changes in the serum lipid patterns due to weight reduction and its association with disease outcomes. Therefore, the lipid patterns in the serum of 14 mature ponies before and after a 14-week body weight reduction program (BWRP) were investigated by multi-one-dimensional thin-layer chromatography (MOD-TLC). Additionally, sensitivity to insulin (SI), body condition scores (BCS) and cresty neck scores (CNS) were measured. A BWRP resulted in a significant loss of body weight (P < 0.001), which was associated with beneficial decreases in BCS and CNS (both, P < 0.001). Serum lipid compositions revealed significantly increased free fatty acid (FFA), sphingomyelin (SM; both P < 0.001), total cholesterol (C) and cholesterol ester (CE) (both P < 0.01) and triacylglycerol (TG; P < 0.05) densities. Improvement of SI after the BWRP was associated with increases in neutral lipids (C, CE and TG, all P < 0.01), FFA and the phospholipid SM (both, P < 0.001). The results show that a BWRP in obese ponies was effective and associated with changes in the concentrations of neutral lipids and the phospholipid SM, indicating that SM may play a role in insulin signaling pathways and thus in the pathogenesis of insulin resistance and the progression of metabolic syndrome in obese ponies.
Lutein is an essential dietary carotenoid with health benefits and is inter alia responsible for the colouration of egg yolk. The relationship between lutein accumulation and egg yolk colouration was therefore studied in more detail. After feeding a low-luteine diet for 21 days, 14 birds (Lohmann brown hens aged 20 weeks) were fed a diet containing marigold (80 mg lutein/kg feed) and 14 other birds were fed a diet containing oleoresin (45 mg lutein/kg feed) for 21 days; for both groups of birds, this feeding period was followed by withdrawal for 21 days. The Roche Yolk Colour Fan (RYCF) score (0 to 15, where higher values denote greater colour intensity; R-2=0.87; P<0.01) and redness (R-2=0.89; P<0.01) increased with increasing lutein content of egg yolk. Total carotenoid content had a poor relationship with lightness (R-2=0.13; P>0.05) and yellowness (R-2=0.12; P>0.05) of the yolk. It may be concluded that increased lutein is potentially responsible for an increased RYCF score and redness (a*), but decreased yellowness (b*) and lightness (L*), of egg yolk.
Background. In horses and ponies numerous medical conditions are known to be linked with inflammation in different tissues, especially in the liver. Besides affecting other metabolic pathways such as the expression of certain interleukins (IL), inflammation is associated with stress of the endoplasmic reticulum (ER). In particular, ER stress leads to adaptive stress response and can be measured by several markers of inflammatory and stress signalling pathways, like nuclear factor kappa B (NF-kB). Objectives. To investigate lipopolysaccharide (LPS)-induced inflammatory reactions and their modulation in horses and ponies by feeding a polyphenol-rich supplement consisting of green tea and curcuma. Methods. In a cross-over study, 11 animals were allocated to either a placebo or a supplement group and supplemented with 10 g of a blend of green tea and curcuma extract (GCE) or a placebo (calcium carbonate) once daily. After 21 days of supplementation, all animals underwent a LPS challenge to induce moderate systemic inflammation. Blood samples and liver biopsies were taken at standardized time points: 24 hours before and 12 hours after LPS challenge. Inflammatory blood parameters such as serum amyloid A (SAA), haptoglobin and retinol binding protein 4 (RBP4) were measured in serum. Hepatic mRNA levels of selected markers of inflammation such as haptoglobin, tumor necrosis factor alpha (TNF-alpha), IL-1 beta, IL-6, cluster of differentiation 68 (CD68), fibroblast growth factor 21 (FGF-21), NF-kappa B, activating transcription factor 4 (ATF4) were quantified by RT-qPCR. In addition, liver biopsies were examined histologically for inflammatory alterations. Results. Blood markers of acute inflammatory response increased after LPS challenge. In the liver, the proinflammatory cytokine IL-1 beta showed significantly lower mRNA levels after LPS challenge in the supplemented group (P = 0.04) compared to the placebo group. Levels of the hepatic CD68 mRNA increased significantly in the placebo group (P = 0.04). There were no significant differences between supplemented and placebo groups concerning other markers of inflammation and markers of ER stress within the liver. The number of hepatic macrophages were not different after LPS challenge in both feeding groups. Conclusion. LPS was able to induce inflammation but seemed less suitable to induce ER stress in the horses and ponies. The polyphenol-rich supplement showed some potential to reduce inflammatory responses. Nevertheless, the supplementation did not exert an overall anti-inflammatory effect in horses and ponies.
Great apes are the closest living relatives of humans. Physiological similarities between great apes and humans provide clues to identify which biological features in humans are primitive or derived from great apes. Vitamin A (VA) and carotenoid metabolism have been only partially studied in great apes, and comparisons between great apes and humans are not available. We aimed to investigate VA and carotenoid intake and plasma concentrations in great apes living in captivity, and to compare them to healthy humans. Dietary intakes of humans (n = 20) and, among the great apes, chimpanzees (n = 15) and orangutans (n = 5) were calculated. Plasma retinol (ROH), retinol-binding protein (RBP), retinyl esters, and major carotenoids were analyzed. The great ape diet was higher in VA than in humans, due to high intake of provitamin A carotenoids. Plasma ROH concentrations in great apes were similar to those in humans, but retinyl esters were higher in great apes than in humans. Differences in plasma carotenoid concentrations were observed between great apes and humans. Lutein was the main carotenoid in great apes, while P-carotene was the main carotenoid for humans. RBP concentrations did not differ between great apes and humans. The molar ratio of ROH to RBP was close to 1.0 in both great apes and humans. In conclusion, great apes show homeostatic ROH regulation, with high but physiological retinyl esters circulating in plasma. Furthermore, great apes show great selectivity in their plasmatic carotenoid concentration, which is not explained by dietary intake.
Carotenoids are lipid-soluble pigments and important for a variety of physiological functions. They are major dietary vitamin A precursors and act as lipophilic antioxidants in a variety of tissues and are associated with important health benefits in humans and animals. All animals must acquire carotenoids from their diet, but to our knowledge, there are no studies investigating the intestinal carotenoid absorption and their blood concentrations in New World camelids. The present study aimed to assess the serum concentrations of selected carotenoids in llamas (n=13) and alpacas (n=27). Serum carotenoids as well as retinol (vitamin A) and -tocopherol (vitamin E) were determined by high-performance liquid chromatography coupled with mass spectrometry and these were unable to detect any carotenoids (- and -carotene, - and -cryptoxanthin, lutein, zeaxanthin, lycopene) in the samples. The concentrations of retinol in alpacas (2.89 +/- 1.13mol/l; mean +/- SD) were higher (p=0.024) than those found in llamas (2.05 +/- 0.87mol/l); however, the concentrations of -tocopherol were not significantly (p=0.166) different (llamas: 3.98 +/- 1.83mol/l; alpacas: 4.95 +/- 2.14mol/l). The results show that both llamas and alpacas are not able to absorb intact carotenoids, but efficiently convert provitamin A carotenoids to retinol.
Background Dietary calcium (Ca) concentrations might affect regulatory pathways within the Ca and vitamin D metabolism and consequently excretory mechanisms. Considering large variations in Ca concentrations of feline diets, the physiological impact on Ca homeostasis has not been evaluated to date. In the present study, diets with increasing concentrations of dicalcium phosphate were offered to ten healthy adult cats (Ca/phosphorus (P): 6.23/6.02, 7.77/7.56, 15.0/12.7, 19.0/17.3, 22.2/19.9, 24.3/21.6 g/kg dry matter). Each feeding period was divided into a 10-day adaptation and an 8-day sampling period in order to collect urine and faeces. On the last day of each feeding period, blood samples were taken. Results Urinary Ca concentrations remained unaffected, but faecal Ca concentrations increased (P < 0.001) with increasing dietary Ca levels. No effect on whole and intact parathyroid hormone levels, fibroblast growth factor 23 and calcitriol concentrations in the blood of the cats were observed. However, the calcitriol precursors 25(OH)D-2 and 25(OH)D-3, which are considered the most useful indicators for the vitamin D status, decreased with higher dietary Ca levels (P = 0.013 and P = 0.033). Increasing dietary levels of dicalcium phosphate revealed an acidifying effect on urinary fasting pH (6.02) and postprandial pH (6.01) (P < 0.001), possibly mediated by an increase of urinary phosphorus (P) concentrations (P < 0.001). Conclusions In conclusion, calcitriol precursors were linearly affected by increasing dietary Ca concentrations. The increase in faecal Ca excretion indicates that Ca homeostasis of cats is mainly regulated in the intestine and not by the kidneys. Long-term studies should investigate the physiological relevance of the acidifying effect observed when feeding diets high in Ca and P.
Despite high-dose vitamin A supplementation of very low birth weight infants (VLBW, <1500 g), their vitamin A status does not improve substantially. Unknown is the impact of urinary retinol excretion on the serum retinol concentration in these infants. Therefore, the effect of high-dose vitamin A supplementation on the urinary vitamin A excretion in VLBW infants was investigated. Sixty-three VLBW infants were treated with vitamin A (5000 IU intramuscular, 3 times/week for 4 weeks); 38 untreated infants were classified as control group. On days 3 and 28 of life, retinol, retinol-binding protein 4 (RBP4), glomerular filtration rate, proteinuria, and Tamm-Horsfall protein were quantified in urine. On day 3 of life, substantial retinol and RBP4 losses were found in both groups, which significantly decreased until day 28. Notwithstanding, the retinol excretion was higher (P<0.01) under vitamin A supplementation as compared to infants of the control group. On day 28 of life, the urinary retinol concentrations were predictive for serum retinol concentrations in the vitamin A treated (P<0.01), but not in the control group (P=0.570). Conclusion: High urinary retinol excretion may limit the vitamin A supplementation efficacy in VLBW infants. Advanced age and thus postnatal kidney maturation seems to be an important contributor in the prevention of urinary retinol losses.