Vitamin D enhanced pork from pigs exposed to artificial UVB light in indoor facilities

Variation in nutritional quality in UK retail eggs

Fatty acid (FA), carotenoid and vitamin contents of UK eggs were assessed for four production systems (caged (CA), free-range (FR), organic (OR) and extensive organic (EO)) as well as season. The impact of enforced housing, due to avian influenza, was also investigated. Production system did not alter vitamin D3, B2 or B9 content, but significantly influenced nutritionally desirable FA, carotenoid and vitamins A and E - concentrations decreased as production intensity increased, although for most, CA and FR did not differ significantly. Vitamin E and FA profiles for OR and EO were also similar, although carotenoids were higher in EO eggs. In contrast, FA, carotenoids, vitamins E and B9 were consistent throughout the year, unlike vitamins A, D3 and B2, which fluctuated with season; D and B2 were higher in July than January and lower vitamin A was the only detected implication from enforced housing of FR and OR birds.

Exposure to artificial ultraviolet-B light mediates alterations on the hepatic transcriptome and vitamin D metabolism in pigs

In the currently prevailing pig husbandry systems, the vitamin D status is almost exclusively dependent on dietary supply. Additional endogenous vitamin D production after exposure to ultraviolet-B (UVB) light might allow the animals to utilize minerals in a more efficient manner, as well as enable the production of functional vitamin D-enriched meat for human consumption. In this study, growing pigs (n = 16) were subjected to a control group or to a daily narrowband UVB exposure of 1 standard erythema dose (SED) for a period of 9 weeks until slaughter at a body weight of 105 kg. Transcriptomic profiling of liver with emphasis on the associated effects on vitamin D metabolism due to UVB exposure were evaluated via RNA sequencing. Serum was analyzed for vitamin D status and health parameters such as minerals and biochemical markers. The serum concentration of calcidiol, but not calcitriol, was significantly elevated in response to UVB exposure after 17 days on trial. No effects of UVB exposure were observed on growth performance and blood test results. At slaughter, the RNA sequencing analyses following daily UVB exposure revealed 703 differentially expressed genes (DEGs) in liver tissue (adjusted p-value < 0.01). Results showed that molecular pathways for vitamin D synthesis (CYP2R1) rather than cholesterol synthesis (DHCR7) were preferentially initiated in liver. Gene enrichment (p < 0.05) was observed for reduced cholesterol/steroid biosynthesis, SNARE interactions in vesicular transport, and CDC42 signaling. Taken together, dietary vitamin D supply can be complemented via endogenous production after UVB exposure in pig husbandry, which could be considered in the development of functional foods.

Improving vitamin D content in pork meat by UVB biofortification

Vitamin D deficiency is prevalent worldwide and identification of alternative food-based strategies are urgently warranted. In two studies, 12-week old crossbred pigs (Duroc x (Large White x Landrace)) were exposed daily to narrowband UVB radiation for ∼10 weeks or control (no UVB exposure) until slaughter. In Study 1 (n = 48), pigs were exposed to UVB for 2 min and in Study 2 (n = 20), this duration was tripled to 6 min. All pigs were fed the maximum permitted 2000 IU vitamin D₃/kg feed. Loin meat was cooked prior to vitamin D LC-MS/MS analysis. In Study 1, pork loin vitamin D₃ did not differ between groups. Study 2 provided longer UVB exposure time and resulted in significantly higher loin vitamin D₃ (11.97 vs. 6.03 μg/kg), 25(OH)D₃ (2.09 vs. 1.65 μg/kg) and total vitamin D activity (22.88 vs. 14.50 μg/kg) concentrations, compared to control (P < 0.05). Pigs remained healthy during both studies and developed no signs of erythema. Biofortification by UVB radiation provides an effective strategy to further safely increase the naturally occurring vitamin D content of pork loin, alongside feed supplementation.

Bio-Fortified Pork Cracklings with UVB LED Tailored Content of Vitamin D3

Since few foods are naturally rich in vitamin D, novel food products with a high content of vitamin D are needed to decrease the prevalence of vitamin D deficiency. Pork cracklings are Danish snacks with high contents of protein and fat. They are consumed mostly during wintertime when sun exposure cannot fulfil human needs for vitamin D3. Pork cracklings were produced in an industrially friendly manner from UVB LED illuminated pork rind, using a combination of sous vide (85 °C, 60 min) and roasting in the oven (200 °C, 20 min). Thermal processing resulted in a significant loss of vitamin D3 (>90%). Thus, the process was optimized by the UVB exposure of pork cracklings, i.e., after thermal processing. The produced pork cracklings had a vitamin D3 level of ~10 µg/100 g, with a possibility of tailoring its final content. Furthermore, the fat content at 15−20% was a reduction of 50% compared to marketed products in 2021. No significant difference was found in the content of vitamin D3 during 31 days of storage in the air. A consumer preference test (n = 53) indicated that >80% of participants liked the product and saw its potential as a new food source of vitamin D3.

Vitamin D Levels in Sows from Five Danish Outdoor Herds

Simple Summary

A cross-sectional study on vitamin D₃ status was conducted in five Danish outdoor sow herds throughout August 2020. The aim was to determine the vitamin D status of outdoor sows during the peak sunshine season. The average 25-hydroxyvitamin D₃ concentration in serum was 67 ± 16 ng 25(OH)D₃/mL in outdoor sows, which is considerably higher than levels found in sows housed indoors and fed a standard diet supplemented with vitamin D.

Abstract

Vitamin D is essential for sow health and productivity. Standard sow feed is therefore supplemented with vitamin D₃ or 25-hydroxyvitamin D₃ (25(OH)D₃). However, it is uncertain whether the levels achieved are adequate for optimal performance. Currently, information on serum levels of vitamin D in pigs reared under both indoor and outdoor conditions is lacking. In August 2020, we obtained blood samples from 97 organic newly weaned sows housed outdoors during pregnancy and farrowing and used these to test for vitamin D in serum. The average concentration was 67 ± 16 ng 25(OH)D₃/mL with a range of 32 to 134 ng 25(OH)D₃/mL. The vitamin D₃ content was 21 ± 7 ng/mL, ranging from 9 to 48 ng/mL. The average number of hours of sun from June to August was 7.0 ± 0.5 h/day. Parity, farm and body condition score did not significantly affect serum levels of 25(OH)D₃.

The future is bright: Biofortification of common foods can improve vitamin D status

Vitamin D deficiency is a global concern, linked to suboptimal musculoskeletal health and immune function, with status inadequacies owing to variations in UV dependent cutaneous synthesis and limited natural dietary sources. Endogenous biofortification, alongside traditional fortification and supplement usage is urgently needed to address this deficit. Evidence reviewed in the current article clearly demonstrates that feed modification and UV radiation, either independently or used in combination, effectively increases vitamin D content of primary produce or ingredients, albeit in the limited range of food vehicles tested to date (beef/pork/chicken/eggs/fish/bread/mushrooms). Fewer human trials have confirmed that consumption of these biofortified foods can increase circulating 25-hydroxyvitamin D [25(OH)D] concentrations (n = 10), which is of particular importance to avoid vitamin D status declining to nadir during wintertime. Meat is an unexplored yet plausible food vehicle for vitamin D biofortification, owing, at least in part, to its ubiquitous consumption pattern. Consumption of PUFA-enriched meat in human trials demonstrates efficacy (n = 4), lighting the way for exploration of vitamin D-biofortified meats to enhance consumer vitamin D status. Response to vitamin D-biofortified foods varies by food matrix, with vitamin D₃-enriched animal-based foods observing the greatest effect in maintaining or elevating 25(OH)D concentrations. Generally, the efficacy of biofortification appears to vary dependent upon vitamer selected for animal feed supplementation (vitamin D₂ or D₃, or 25(OH)D), baseline participant status and the bioaccessibility from the food matrix. Further research in the form of robust human clinical trials are required to explore the contribution of biofortified foods to vitamin D status.

Vitamin D composition of Australian foods

Australia needs accurate vitamin D food composition data to support public health initiatives. Previously, limitations in analytical methodology have precluded development of a comprehensive database. We used liquid chromatography with triple quadrupole mass spectrometry (LC-QQQ) to analyse 149 composite samples representing 98 foods (primary samples n = 896) in duplicate for vitamin D₃, 25-hydroxyvitamin D₃ (25(OH)D₃), vitamin D₂, 25(OH)D₂. The greatest concentrations of vitamin D₃ were found in canned salmon and a malted chocolate drink powder (fortified); chicken eggs and chicken leg meat contained the most 25(OH)D₃. Margarine (fortified) and chocolate contained the greatest concentrations of vitamin D₂, with smaller amounts found in various meat products. 25(OH)D₂ was detected in various foods, including meats, and was quantitated in lamb liver. These data advance knowledge of dietary vitamin D in Australia and highlight the importance of analysis of these four forms of vitamin D to accurately represent the vitamin D content of food.

Quantification of vitamin D3 and 25-hydroxyvitamin D3 in food - The impact of eluent additives and labelled internal standards on matrix effects in LC-MS/MS analysis

Deuterated vitamin D standards are used commonly as internal standards in LC-MS/MS analysis of vitamin D3 and 25-hydroxyvitamin D3 in food. However, the use of various eluent additives, such as methylamine, formic acid and ammonium formate, also contributes to matrix effects and the performance of analysis by affecting accuracy and robustness. For the first time, continuous post-column infusion experiments of isotopically labelled vitamin D3-[d6] were performed to evaluate ion-suppression in a wide variety of food (salmon, cheese, pork fat, pork meat, and egg yolk). Furthermore, results collected using five analytical methods, employing DAD/UV and MS/MS-detectors, were evaluated with in-house and standardised reference materials. The matrix effect was significant when analysing vitamin D3 in most food matrices using the deuterium labelled internal standard. Even though the use of the 13C5-labelled internal standard reduced matrix effects, a standardised method is needed to agree on the true value of vitamin D in food.

Natural Vitamin D in Food: To What Degree Does 25-Hydroxyvitamin D Contribute to the Vitamin D Activity in Food?

Vitamin D3, vitamin D2, 25-hydroxyvitamin D3 [25(OH)D₃], and 25-hydroxyvitamin D2 [25(OH)D₂]constitute the vitamin D activity in food. In general, vitamin D activity in food depends on the food's fat content, the feed the animals have been fed, and the animal's exposure to ultraviolet B (UVB) light. There are many gaps in our knowledge of 25-hydroxyvitamin D in food, including the amount present in different types of food, and the amount we process in our daily dietary intake. We aimed to assess the vitamin D vitamers in food (eggs, milk, dairy products, chicken, veal, beef, and pork) on the Danish market using accredited analytical methods. We then combined these data with existing Danish data, as well as with the information from the Danish Dietary Survey to estimate the dietary intake of vitamin D3 and of 25(OH)D₃ by Danes. We report the level of vitamin D in 10% minced pork from free-range pigs slaughtered in summer as 1.39 μg vitamin D3/100 g and 0.40 μg 25(OH)D₃/100 g, which are significantly higher amounts (p < 0.001) than in early spring. The levels of vitamin D2 and 25(OH)D₂ are usually <0.05 μg/100 g, though in beef they are up to 0.14 μg/100 g. 25(OH)D₃ accounts for up to 100% in veal and 8% in fat from free-range pigs. In the Danish diet, the share of 25(OH)D₃ is 24% for children (4-17 years) and 18% for adults (18-75 years). Changes in animal-feeding strategy in the agriculture sector could change the share of 25(OH)D₃ to 11% and 12% if extra vitamin D3 is added to the feed, and the animals are exposed to sunlight or UVB lightlight. Replacing vitamin D3 by 25(OH)D₃ in the feed may result in a share of 25(OH)D₃ of 52% and 40%, respectively, in children and adults. These estimates are based on the assumption that vitamin D3 and 25(OH)D₃ contribute equally to the vitamin D activity. © 2020 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Vitamin D-enhanced pork meat consumers’ purchase intention: an exploratory case study in Spain

Abstract: This paper investigated if Spanish consumers would be willing to consume vitamin D-enhanced pork meat from animals fed on mushrooms treated with ultraviolet (UV) light. The questionnaire briefly explained the context of the study (vitamin D deficiency) and asked the consumers to choose answers with which they were most in agreement (non-enriched meat, enriched meat with synthetic vitamin D or enriched meat with vitamin D from UV-irradiated mushrooms). A survey was conducted to 400 non-vegan nor vegetarian consumers in Aragón (Spain) by direct invitation. Sampling was carried out in a random and stratified manner, by province, gender and age group using the Aragón population data for 2017 (INE). Some sociodemographic, health and consumption habit data were requested. Most consumers preferred non-enriched meat. Treatment with UV-irradiated mushrooms was rejected by most consumers, and the consumers who presented any willingness to buy meat enriched with UV-irradiated mushrooms were in the youngest age group.

Collaborative study: Quantification of total folate in food using an efficient single-enzyme extraction combined with LC-MS/MS

Quantification of the specific folate vitamers to estimate total folate in foods is not standardized. A collaborative study, including eight European laboratories, was conducted in order to determine the repeatability and reproducibility of the method for folate quantification in foods using the plant-origin γ-glutamyl hydrolase as part of the extraction procedure. The seven food samples analyzed represent the food groups; fruits, vegetables, dairy products, legumes, offal, fish, and fortified infant formula. The homogenization step was included, and six folate vitamers were analyzed using LC-MS/MS. Total folate content, expressed as folic acid equivalent, was 17-490 μg/100 g in all samples. Horwitz ratio values were within the acceptable range (0.60-1.94), except for fish. The results for fortified infant formula, a certified reference material (NIST 1869), confirmed the trueness of the method. The collaborative study is part of a standardization project within the Nordic Committee on Food Analysis (NMKL).

Vitamin K (phylloquinone and menaquinones) in foods - Optimisation of extraction, clean-up and LC-ESI-MS/MS method for quantification

Growing evidence of vitamin K's importance in human health beyond blood coagulation and bone health necessitates its further research. A method involving extraction, lipase treatment, clean-up, and detection and quantification by LC-ESI-MS/MS of phylloquinone (PK), menaquinone-4 (MK-4), menaquinone-7 (MK-7) and menaquinone-9 (MK-9) was developed, and single-laboratory validated. The matrices included in the validation were hazelnut, cheese, broccoli, and pork. The LC-method runtime was 9 min. The LOQ for PK, MK-4 and MK-7 was 0.5 µg/100 g food, while for MK-9 it was 2.5 µg/100 g food. The intra- and inter-day precision was <15% for endogenous and spiked levels, except for low content at 4 times the LOQ. Trueness was assessed to be in the range 94-125% for spiking at levels approximately 4 and 10 times LOQ. It is further shown that deuterium labelled MK-7 can be used as an internal standard for MK-9.

Effect of UVB light on vitamin D status in piglets and sows

Piglets are born with very low levels of vitamin D. Feed is the only source of vitamin D for pigs kept indoors, and the levels in feed are restricted by European legislation. We aimed to study the effect of lamps releasing ultraviolet type B (UVB) light on the vitamin D status (serum 25-hydroxyvitamin D) in sows and piglets in a Danish indoor herd. A randomized trial with a parallel group design was initiated with two groups receiving a daily UVB-dose of maximum 0.7 standard erythema dose (SED) or 1 SED, in addition to a control group. The three groups included in the study consisted of 15 sows and their 195 offspring. Blood samples were taken from the piglets and sows on day 1, 12, and 24. Results showed no difference between the groups in serum levels of 25(OH)D₃ or vitamin D₃ on day 1, with the mean (±SD) for piglets being 0.96 ± 0.26 ng/mL and 0.06 ± 0.04 ng/mL, respectively. For sows, the values were 16 ± 3 ng/mL 25(OH)D₃ and 3 ± 0.8 ng/mL vitamin D₃ on day 1. A significant difference (p < 0.001) in serum 25(OH)D₃ between the groups receiving UVB light and the control group was observed on both day 12 and day 24. On day 24, the piglet control group had 5.5 ± 2 ng/mL 25(OH)D₃ and 0.4 ± 0.2 ng/mL vitamin D₃. For the UVB groups, the values were 21.6 ± 10. ng/mL 25(OH)D₃ and 8.3 ± 2.5 ng/mL vitamin D₃ for the 0.7 SED group and 19.5 ± 6.0 ng/mL 25(OH)D₃ and 7.6 ± 3.4 ng/mL vitamin D₃ for the 1 SED group. For the sows, the values were 25.6 ± 5.5 ng/mL 25(OH)D₃ and 6.6 ± 1.2 ng/mL vitamin D₃ for the control group, 66.7 ± 13.5 ng/mL 25(OH)D₃ and 21.3 ± 2.9 ng/mL vitamin D₃ for 0.7 SED group and 67 ± 15 ng/mL 25(OH)D₃ and 25 ± 5 ng/mL vitamin D₃ for the 1 SED. No significant difference was found between the two UVB groups for either piglets or sows. The use of lamps releasing UVB light is therefore suggested to be an efficient way to improve the vitamin D status of both sows and piglets.

Microalgae Nannochloropsis oceanica as a future new natural source of vitamin D3

For the last two decades there has been a rise in awareness about the general low dietary intake of vitamin D₃. Fish have the highest natural content of vitamin D₃, which is suggested to originate from zooplankton and microalgae. However there are no studies reporting which microalgal species may be the source of vitamin D₃. In this study, four selected microalgal species were cultivated during exposure of artificial UVB. The effect of UVB dose on the growth and biochemical composition of the cells (vitamin D₃, PUFAs and carotenoids) was evaluated. Of the four species, exclusively Nannochloropsis oceanica was able to produce vitamin D₃ (up to 1 ± 0.3 µg/g DM), and production was significantly enhanced by increasing the dose of the UVB. These findings suggest that N.oceanica exposed to artificial UVB could be used as a new natural source of vitamin D_3, either as direct source or through animal feed.

Challenges to Quantify Total Vitamin Activity: How to Combine the Contribution of Diverse Vitamers?

This state-of-the-art review aims to highlight the challenges in quantifying vitamin activity in foods that contain several vitamers of a group, using as examples the fat-soluble vitamins A and D as well as the water-soluble folate. The absorption, metabolism, and physiology of these examples are described along with the current analytical methodology, with an emphasis on approaches to standardization. Moreover, the major food sources for the vitamins are numerated. The article focuses particularly on outlining the so-called SLAMENGHI factors influencing a vitamer's' ability to act as a vitamin, that is, molecular species, linkage, amount, matrix, effectors of absorption, nutrition status, genetics, host-related factors, and the interaction of these. After summarizing the current approaches to estimating the total content of each vitamin group, the review concludes by outlining the research gaps and future perspectives in vitamin analysis. There are no standardized methods for the quantification of the vitamers of vitamin A, vitamin D, and folate in foods. For folate and β-carotene, a difference in vitamer activity between foods and supplements has been confirmed, whereas no difference has been observed for vitamin D. For differences in vitamer activity between provitamin A carotenoids and retinol, and between 25-hydroxyvitamin D and vitamin D, international consensus is lacking. The challenges facing each of the specific vitamin communities are the gaps in knowledge about bioaccessibility and bioavailability for each of the various vitamers. The differences between the vitamins make it difficult to formulate a common strategy for assessing the quantitative differences between the vitamers. In the future, optimized stationary digestive models and the more advanced dynamic digestive models combined with in vitro models for bioavailability could more closely resemble in vivo results. New knowledge will enable us to transfer nutrient recommendations into improved dietary advice to increase public health throughout the human life cycle.

Is high oily fish intake achievable and how does it affect nutrient status in 8-9-year-old children?: the FiSK Junior trial

PURPOSE

Most children do not meet dietary guidelines for fish intake. Fish is the main source of EPA (20:5n-3), DHA (22:6n-3) and vitamin D, but may replace better iron sources such as meat. We investigated if intake of 300 g/week oily fish was achievable in children and how it affected their nutrient status. Additionally, we validated a fish food frequency questionnaire (FFQ) by correlations against EPA + DHA in red blood cells (RBC).

METHODS

In a randomised 12-week trial, 199 children (8-9 years) received oily fish or poultry (control) to be eaten five times/week. We measured dietary intake and analysed fasting RBC EPA + DHA, serum 25-hydroxyvitamin D (25(OH)D), blood haemoglobin and plasma ferritin.

RESULTS

197 (99%) children completed the study. The median (25th-75th percentile) intake was 375 (325-426) and 400 (359-452) g/week oily fish and poultry, respectively. The fish group increased their intake of EPA + DHA by 749 (593-891) mg/day and vitamin D by 3.1 (1.6-3.8) µg/day. Endpoint RBC EPA + DHA was 2.3 (95% CI 1.9; 2.6) fatty acid %-point higher than the poultry group (P < 0.001). The fish group avoided the expected 25(OH)D winter decline (P < 0.001) and had 23%-point less vitamin D insufficiency (winter subgroup, n = 82). Haemoglobin and ferritin decreased slightly in both groups (P < 0.05), but the number of children with low values did not change (P > 0.14). FFQ estimates moderately reflected habitual intake (r = 0.28-0.35) and sufficiently captured intervention-introduced changes in intake (r > 0.65).

CONCLUSION

Oily fish intake of 300 g/week was achievable and improved children's EPA + DHA and 25(OH)D status, without markedly compromising iron status. These results justify public health initiatives focusing on children's fish intake.

Vitamin D in Wild and Farmed Atlantic Salmon (Salmo Salar)-What Do We Know?

Salmon have been widely publicized as a good dietary source of vitamin D, but recent data points to large variation in vitamin D content and differences between wild and farmed salmon. We aimed to: (1) investigate the content of vitamin D in Atlantic salmon (Salmo salar) in wild species caught in two different waters, (2) perform a 12-week feeding trial in farmed Salmo salar with 270-1440 µg vitamin D3/kg feed (4-20 times maximum level in the EU) and (3) conduct a review for the published data on the content of vitamin D in salmonids. Content of vitamin D3 in the fillet from wild salmon caught in the Baltic Sea and the North Sea was significantly different (p < 0.05), being 18.5 ± 4.6 µg/100 g and 9.4 ± 1.9 µg/100 g, respectively. In the farmed salmon the content ranged from 2.9 ± 0.7 µg vitamin D3/100 g to 9.5 ± 0.7 µg vitamin D3/100 g. Data from 2018 shows that farmed salmon contained 2.3-7.3 µg vitamin D3/100 g. Information on the content of vitamin D in wild and farmed salmonids is very limited, which calls for further research to ensure a sustainable production of salmon with adequate vitamin D.