Improvement of maternal vitamin D status with 25-hydroxycholecalciferol positively impacts porcine fetal skeletal muscle development and myoblast activity

A sustainable nutritional solution for fattening pigs based on 25-hydroxycholecalciferol and triterpenoids added to a low Ca diet containing phytase improves growth performance via the activation of muscle protein synthesis without compromising bone mineralization

In the current climate of sustainable animal agriculture, nutritional strategies that support fattening swine growth performance and bone mineralization whilst reducing environmental impacts are much sought after. This study evaluated the effect of supplementing 25(OH)D3 with triterpenoids to a Ca-reduced diet containing phytase during the grower-finisher phase. Growth performance, bone composition, plasma metabolites and muscle gene expression were evaluated. Sixty crossbreed boar pigs (initial body weight (BW) 42.0 ± 5.1 kg at 12 wk of age) were assigned to three treatments with 20 pigs/treatment in a completely randomized design. Treatments comprised: 1) a standard commercial grower-finisher diet (positive control (PC)) containing 1,500 IU/kg vitamin D3 [3,585 kcal/kg digestible energy, 16.19% CP, 0.70% Ca, 0.29% standardized total tract digestible P]; 2) a negative control (NC) based on the PC with reduction in Ca and P (minus 30% and 10%, respectively); 3) the NC with vitamin D3 replaced by a commercially available compounds combination containing 25(OH)D3 and triterpenoids, dosed at 500 mg per kg of feed (TRT). All diets were provided ad libitum for 7 wk, and feed intake was recorded individually via electronic feeder stations. For the overall period, average daily gain and average daily feed intake were increased (P < 0.05) in TRT vs. NC or PC (+ 13.0% and + 8.3%, respectively, vs. NC); final BW was 7.8% higher vs. NC (+ 5.2% vs. PC; P < 0.05). Whole-body DXA-scanning at 19 wk of age showed that bone mineral density, content and percentage were reduced in NC vs. PC and equivalent to PC in TRT. Plasma 25(OH)D3 and P levels were raised in TRT (+ 33 ng/ml or 2.6-fold and + 0.55 mg/dL or 5.9%, respectively, vs. NC). The combination of 25(OH)D3 with triterpenoids was found to activate several biological pathways involved in muscle growth, including pathways that activate mTOR, a key central regulator of cell metabolism, growth, proliferation and survival when the gene expression was measured in the muscle tissue at 19 wk of age. These results suggest that the dietary combination of 25(OH)D3 with triterpenoids has the potential for use, alongside phytase, in supporting a reduction in Ca and P in the diet to reduce nutrient waste and improve the sustainability of production by promoting muscle growth and maintaining bone composition.

Research Progress on the Regulating Factors of Muscle Fiber Heterogeneity in Livestock: A Review

The type of muscle fiber plays a crucial role in the growth, development, and dynamic plasticity of animals' skeletal muscle. Additionally, it is a primary determinant of the quality of both fresh and processed meat. Therefore, understanding the regulatory factors that contribute to muscle fibers' heterogeneity is of paramount importance. Recent advances in sequencing and omics technologies have enabled comprehensive cross-verification of research on the factors affecting the types of muscle fiber across multiple levels, including the genome, transcriptome, proteome, and metabolome. These advancements have facilitated deeper exploration into the related biological questions. This review focused on the impact of individual characteristics, feeding patterns, and genetic regulation on the proportion and interconversion of different muscle fibers. The findings indicated that individual characteristics and feeding patterns significantly influence the type of muscle fiber, which can effectively enhance the type and distribution of muscle fibers in livestock. Furthermore, non-coding RNA, genes and signaling pathways between complicated regulatory mechanisms and interactions have a certain degree of impact on muscle fibers' heterogeneity. This, in turn, changes muscle fiber profile in living animals through genetic selection or environmental factors, and has the potential to modulate the quality of fresh meat. Collectively, we briefly reviewed the structure of skeletal muscle tissue and then attempted to review the inevitable connection between the quality of fresh meat and the type of muscle fiber, with particular attention to potential events involved in regulating muscle fibers' heterogeneity.

Efficacy of dietary vitamin D3 and 25(OH)D3 on reproductive capacities, growth performance, immunity and bone development in pigs

Vitamin D3 (Vit D3) and 25(OH)D3 are used as dietary sources of active vitamin D (1,25(OH)2D3) in pig husbandry. Although acting primarily on intestine, kidney and bone, their use in pig nutrition has shown a wide range of effects also in peripheral tissues. However, there is an ambiguity in the existing literature about whether the effects of Vit D3 and 25(OH)D3 differ in attributing the molecular and phenotypic outcomes in pigs. We searched Web of Science and PubMed databases concerning the efficacy of Vit D3 in comparison with 25(OH)D3 on pig physiology, i.e. reproductive capacities, growth performance, immunity and bone development. Dietary intake of Vit D3 or 25(OH)D3 did not influence the reproductive capacity of sows. Unlike Vit D3, the maternal intake of 25(OH)D3 significantly improved the growth performance of piglets, which might be attributed to maternally induced micronutrient efficiency. Consequently, even in the absence of maternal vitamin D supplementation, 25(OH)D3-fed offspring also demonstrated better growth than the offspring received Vit D3. Moreover, a similar superior impact of 25(OH)D3 was seen with respect to serum markers of innate and humoral immunity. Last but not least, supplements containing 25(OH)D3 were found to be more effective than Vit D3 to improve bone mineralisation and formation, especially in pigs receiving basal diets low in Ca and phosphorus. The insights are of particular value in determining the principal dietary source of vitamin D to achieve its optimum utilisation efficiency, nutritional benefits and therapeutic potency and to further improve animal welfare across different management types.

Month-of-Birth Effect on Muscle Mass and Strength in Community-Dwelling Older Women: The French EPIDOS Cohort

Background. Vitamin D is involved in muscle health and function. This relationship may start from the earliest stages of life during pregnancy when fetal vitamin D relies on maternal vitamin D stores and sun exposure. Our objective was to determine whether there was an effect of the month of birth (MoB) on muscle mass and strength in older adults. Methods. Data from 7598 community-dwelling women aged ≥ 70 years from the French multicentric EPIDOS cohort were used in this analysis. The quadricipital strength was defined as the mean value of 3 consecutive tests of the maximal isometric voluntary contraction strength of the dominant lower limb. The muscle mass was defined as the total appendicular skeletal muscle mass measured using dual energy X-ray absorptiometry scanner. The MoB was used as a periodic function in regressions models adjusted for potential confounders including age, year of birth, latitude of recruitment center, season of testing, body mass index, number of comorbidities, IADL score, regular physical activity, sun exposure at midday, dietary protein intake, dietary vitamin D intake, use vitamin D supplements, history and current use of corticosteroids. Results. A total of 7133 older women had a measure of muscle strength (mean age, 80.5 ± 3.8 years; mean strength, 162.3 ± 52.1 N). Data on total ASM were available from 1321 women recruited in Toulouse, France (mean, 14.86 ± 2.04 kg). Both the sine and cosine functions of MoB were associated with the mean quadricipital strength (respectively β = -2.1, p = 0.045 and β = -0.5, p = 0.025). The sine function of MoB was associated with total ASM (β = -0.2, p = 0.013), but not the cosine function (β = 0.1, p = 0.092). Both the highest value of average quadricipital strength (mean, 163.4 ± 20.2 N) and the highest value of total ASM (15.24 ± 1.27 kg) were found among participants born in August. Conclusions. Summer-early fall months of birth were associated with higher muscle mass and strength in community-dwelling older women.

Dietary supplementation of 25-hydroxycholecalciferol as an alternative to cholecalciferol in swine diets: A review

25-hydroxycholecalciferol (25-OHD₃ ) formed via hepatic hydroxylation from vitamin D, cholecalciferol, represents the precursor of the biologically active vitamin D hormone, 1,25-dihydroxyvitamin D. Due to a higher absorption rate and the omission of one hydroxylation, dietary supplementation of 25-OHD₃ instead of vitamin D₃ is considered to be more efficient as plasma concentrations of 25-OHD₃ are increased more pronounced. The present review summarises studies investigating potential beneficial effects on mineral homeostasis, bone metabolism, health status and performance in sows, piglets and fattening pigs. Results are inconsistent. While most studies could not demonstrate any or only a slight impact of partial or total replacement of vitamin D₃ by 25-OHD₃ , some experiments indicated that 25-OHD₃ might alter physiological processes when animals are challenged, for example, by a restricted mineral supply.

Effect of combined maternal and post-hatch dietary 25-hydroxycholecalciferol supplementation on broiler chicken Pectoralis major muscle growth characteristics and satellite cell mitotic activity

Skeletal muscle growth is largely dependent on the proliferation and differentiation of muscle-specific stem cells known as satellite cells (SC). Previous work has shown that dietary inclusion of the vitamin D3 metabolite, 25-hydroxycholecalciferol (25OHD3), also called calcidiol, can promote skeletal muscle growth in post-hatch broiler chickens. Improving vitamin D status of broiler breeder hens by feeding 25OHD3 in addition to vitamin D3 has also been shown to positively impact progeny. Yet, whether combined pre- and post-hatch supplementation with 25OHD3 produces an additive or synergistic SC-mediated, skeletal muscle growth response remains unanswered. To evaluate the effect of combined maternal and post-hatch dietary 25OHD3 supplementation on the growth and SC mitotic activity of the Pectoralis major (PM) muscles in broiler chickens, a randomized complete block design experiment with the main effects of maternal diet (MDIET) and post-hatch diet (PDIET) arranged in a 2 × 2 factorial treatment structure was conducted. From 25 to 36 wk of age, broiler breeder hens were fed 1 of 2 MDIET formulated to provide 5,000 IU D3 (MCTL) or 2,240 IU of D3 + 2,760 IU of 25OHD3 per kg of feed (M25OHD3). Their male broiler chick offspring (n = 400) hatched from eggs collected from 35 to 36 wk of age were reared in raised floor pens. Broilers were fed 1 of 2 PDIET formulated to provide 5,000 IU of D3 per kg of feed (PCTL) or 2,240 IU of D3 + 2,760 IU of 25OHD3 per kg of feed (P25OHD3). Muscle was collected at days 4, 8, 15, 22, and 29 and stored until immunofluorescence analysis. Data were analyzed as a 2-way ANOVA with SAS GLIMMIX. Dietary 25OHD3 was effectively transferred from hen plasma to egg yolks (P = 0.002) and to broiler progeny plasma (days 4 to 22; P ≤ 0.044). Including 25OHD3 in either MDIET or PDIET altered PM hypertrophic growth prior to day 29 (P ≥ 0.001) and tended to reduce Wooden Breast severity (P ≤ 0.089). Mitotic SC populations were increased in PM of MCTL:P25OHD3 and M25OHD:PCTL-fed broilers at d 4 (P = 0.037). At d 8, the PM mitotic SC populations were increased 33% by P25OHD3 (P = 0.054). The results of this study reveal that combined maternal and post-hatch 25OHD3 supplementation does not produce additive or synergistic effects on SC-mediated broiler muscle growth. However, vitamin D status improvement through dietary 25OHD3 inclusion in either the maternal or post-hatch diet stimulated broiler breast muscle growth by increasing proliferating SC populations.

Maternal vitamin D deficiency affects the morphology and function of glycolytic muscle in adult offspring rats

BACKGROUND

Fetal stage is a critical developmental window for the skeletal muscle, but little information is available about the impact of maternal vitamin D (Vit. D) deficiency (VDD) on offspring lean mass development in the adult life of male and female animals.

METHODS

Female rats (Wistar Hannover) were fed either a control (1000 IU Vit. D3/kg) or a VDD diet (0 IU Vit. D3/kg) for 6 weeks and during gestation and lactation. At weaning, male and female offspring were randomly separated and received a standard diet up to 180 days old.

RESULTS

Vitamin D deficiency induced muscle atrophy in the male (M-VDD) offspring at the end of weaning, an effect that was reverted along the time. Following 180 days, fast-twitch skeletal muscles [extensor digitorum longus (EDL)] from the M-VDD showed a decrease (20%; P < 0.05) in the number of total fibres but an increase in the cross-sectional area of IIB (17%; P < 0.05), IIA (19%; P < 0.05) and IIAX (21%; P < 0.05) fibres. The fibre hypertrophy was associated with the higher protein levels of MyoD (73%; P < 0.05) and myogenin (55% %; P < 0.05) and in the number of satellite cells (128.8 ± 14 vs. 91 ± 7.6 nuclei Pax7 + in the M-CTRL; P < 0.05). M-VDD increased time to fatigue during ex vivo contractions of EDL muscles and showed an increase in the phosphorylation levels of IGF-1/insulin receptor and their downstream targets related to anabolic processes and myogenic activation, including Ser ⁴⁷³ Akt and Ser ^21/9 GSK-3β. In such muscles, maternal VDD induced a compensatory increase in the content of calcitriol (two-fold; P < 0.05) and CYP27B1 (58%; P < 0.05), a metabolizing enzyme that converts calcidiol to calcitriol. Interestingly, most morphological and biochemical changes found in EDL were not observed in slow-twitch skeletal muscles (soleus) from the M-VDD group as well as in both EDL and soleus muscles from the female offspring.

CONCLUSIONS

These data show that maternal VDD selectively affects the development of type-II muscle fibres in male offspring rats but not in female offspring rats and suggest that the enhancement of their size and fatigue resistance in fast-twitch skeletal muscle (EDL) is probably due to a compensatory increase in the muscle content of Vit. D in the adult age.

Effect of Different Basal Culture Media and Sera Type Combinations on Primary Broiler Chicken Muscle Satellite Cell Heterogeneity during Proliferation and Differentiation

Simple Summary

Little consistency in the literature exists for optimal culture conditions for proliferating and differentiating primary broiler chicken muscle satellite cells regarding basal culture media, proliferation sera, and differentiation sera. This experiment assessed primary satellite cell proliferation and differentiation when cultured in different combinations of basal media and sera. Cells were cultured in different basal media: low glucose Dulbecco’s Modified Eagle’s medium, McCoy’s 5A, and high glucose Dulbecco’s Modified Eagle’s medium. Each media was supplemented with 15% chicken serum, or a combination of 5% horse serum + 10% chicken serum during proliferation while 3% horse serum or 3% chicken serum were supplemented during differentiation. Cultures were immunofluorescence stained for myogenic regulatory factors at different time points during proliferation and differentiation. During proliferation and differentiation, cells cultured in Dulbecco’s Modified Eagle’s medium tended to have higher proportions of myogenic cells expressing myogenic regulatory factors and promoted satellite cell fusion into myotubes compared with McCoy’s 5A. Low glucose media, glucose concentration similar to circulating glucose concentrations in broilers, combined with sera published in the literature may be the optimal culture media to promote satellite cell proliferation and differentiation.

Abstract

The objective of this experiment was to access primary satellite cell (SC) proliferation and differentiation when cultured in different combinations of basal media and sera due to little consistency being published on the optimal culture media for primary broiler chicken satellite cells. Cells were cultured in one of three different basal media: McCoy’s 5A, high glucose Dulbecco’s Modified Eagle’s medium (DMEM), and low glucose DMEM. Media were supplemented with 15% chicken serum (CS) or a combination of 5% horse serum (HS) + 10% CS during proliferation while 3% HS or 3% CS were added to the media during differentiation. Cultures were immunofluorescence stained for myogenic regulatory factors (MRF) at 48, 72, and 96 h post-plating for proliferation (Pax7, MyoD, and Myf-5) and 96 h post-proliferation during differentiation (Pax7 and MyoD), including MF20 to assess fusion. Cells cultured in Dulbecco’s Modified Eagle’s medium tended to have higher proportions of myogenic cells expressing MRF during proliferation and promoted fusion into myotubes compared with McCoy’s 5A during differentiation. Culturing primary SC in low glucose media, glucose concentrations similar to circulating glucose concentrations in broilers, HSCS during proliferation and CS during differentiation, appears to be optimal for promoting broiler chicken satellite cell proliferation and differentiation.

Dietary 25(OH)D3 supplementation to gestating and lactating sows and their progeny affects growth performance, carcass characteristics, blood profiles and myogenic regulatory factor- related gene expression in wean-finish pigs

Objective

This experiment investigated the effects of supplementing vitamin D₃-fortified sow and progeny diets with 25(OH)D₃ on growth performance, carcass characteristics, immunity, and pork meat quality.

Methods

The present study involved the assessment of supplementing the diet of sows and their progeny with or without 25 (OH)D₃ in a 2×2 factorial arrangement on the performance and production characteristics of wean-finish pigs. Forty-eight multiparous sows were assigned to a basal diet containing 2000 IU/kg vitamin D₃ and supplemented without (CON) or with (TRT) 50 μg/kg 25 (OH)D₃. At weaning, a total of 80 pigs each from CON and TRT sows were allocated to weaning and growing-finishing basal diets fortified with 2,500 and 1,750 IU/kg vitamin D₃ respectively and supplemented without or with 50 μg/kg 25(OH)D₃.

Results

Sows fed 25(OH)D₃-supplemented diets improved pre-weaning growth rate of nursing piglets. A significant sow and pig weaning diet effect was observed for growth rate and feed efficiency (p<0.05) during days 1 to 42 post-weaning. Pigs consuming 25(OH)D₃-supplemented diets gained weight faster (p = 0.016), ate more (p = 0.044) and tended to convert feed to gain more efficiently (p = 0.088) than those fed CON diet between days 98 and 140 post-weaning. Supplemental 25(OH)D₃ improved water holding capacity and reduced drip loss of pork meat, increased serum 25(OH)D₃ level, produced higher interleukin-1 and lower interleukin-6 concentrations in blood circulation, downregulated myostatin (MSTN) and upregulated myogenic differentiation (MYOD) and myogenic factor 5 (MYF5) gene expressions (p<0.05).

Conclusion

Supplementing vitamin D₃-fortified sow and wean-finish pig diets with 50 μg/kg 25(OH)D₃ significantly improved production performance suggesting their current dietary vitamin D₃ levels are insufficient. In fulfilling the total need for vitamin D, it is strongly recommended to add 50 μg/kg 25(OH)D₃ “on top” to practical vitamin D₃-fortified sow and wean-finish pig diets deployed under commercial conditions.

Dietary Betaine Addition Alters Carcass Traits, Meat Quality, and Nitrogen Metabolism of Bama Mini-Pigs

Betaine is widely used as feed additives in animal husbandry as it can cause many benefits such as improving antioxidant ability, growth performance, and carcass traits. However, there are limited studies about the effects of betaine on the Bama mini-pigs. The present study was conducted to evaluate the effects of dietary betaine on carcass traits, meat quality, and nitrogen metabolism of pigs. Twenty-six pregnant Bama mini-pigs and then 104 weaned piglets were assigned for experimental treatments. The plasma and muscle samples were collected at 65-, 95-, and 125-d-old pigs, respectively. The results showed that betaine addition in the sow-offspring diets increased the lean meat rate in the 65-d-old pigs, whereas carcass weight, carcass yield, and loin-eye area were increased in the 95-d-old pigs, and carcass weight and backfat thickness in the 125-d-old pigs. Dietary betaine addition in the sow-offspring diets increased the contents of plasma Asp of 65-d-old, Met of 95- and 125-d-old, and Sar of 125-d-old pigs. Moreover, betaine addition increased the contents of Met, His, Ile, and Phe in Longissimus thoracis et lumborum, whereas those contents were decreased in biceps femoris and psoas major muscles at different stages. Betaine addition in the sow and piglets' diets regulated the muscle fiber-type and myogenic regulatory gene expressions. In summary, betaine addition in the sow and sow-offspring diets could improve the carcass traits and meat quality by altering the plasma biochemical parameters, amino acid composition, and gene expressions of skeletal muscle.

Use of 25-hydroxyvitamin D3 in diets for sows: A review

Dietary supplementation with 25-hydroxyvitamin D₃ (25OHD₃), as an alternative source of vitamin D, is becoming increasingly popular due to its commercialization and more efficient absorbability. The addition of 25OHD₃ rather than its precursor vitamin D₃ can circumvent the 25-hydroxylation reaction in the liver, indicating that supplementation of 25OHD₃ can rapidly improve the circulating vitamin D status of animals. Emerging experiments have reported that maternal 25OHD₃ supplementation could increase sow performances and birth outcomes and promote circulating vitamin D status of sows and their offspring. Increased milk fat content was observed in many experiments; however, others demonstrated that adding 25OHD₃ to lactating sow diets increased the contents of milk protein and lactose. Although an inconsistency between the results of different experiments exists, these studies suggested that maternal 25OHD₃ supplementation could alter milk composition via its effects on the mammary gland. Previous studies have demonstrated that adding 25OHD₃ to sow diets could improve the mRNA expressions of insulin-induced gene 1 (INSIG1) and sterol regulatory element-binding protein 1 (SREBP1) in the mammary gland cells from milk and increase the mRNA expressions of acetyl-CoA carboxylase α (ACCα) and fatty acid synthase (FAS) in the mammary gland tissue. Maternal 25OHD₃ supplementation promotes skeletal muscle development of piglets before and after parturition, and improves bone properties including bone density and bone breaking force in lactating sows and their piglets. Interestingly, 25OHD₃ supplementation in sow diets could improve neonatal bone development via regulation of milk fatty acid composition related to bone metabolism and mineralization. In this review, we also discuss the effects of adding 25OHD₃ to sow diets on the gut bacterial metabolites of suckling piglets, and propose that butyrate production may be associated with bone health. Therefore, to better understand the nutritional functions of maternal 25OHD₃ supplementation, this paper reviews advances in the studies of 25OHD₃ for sow nutrition and provides references for practical application.

Free-range system and supplementation of 25-hydroxicholecalciferol increases the performance and serum vitamin levels in mixed-parity sows

Improvements in sow productivity have raised questions regarding dietary vitamin D recommendations. The present study aimed to evaluate the effects of the housing system with access to sunlight exposure and supplementation of 25-hydroxicholecalciferol on performance and serum levels of 25(OH)D₃ in sows during gestation and lactation. Sows were distributed in an experimental design with two housing systems: gestation crates or gestation free-range system with external area for sunlight exposure; and two diets: 0 or 50 μg of 25-hydroxicholecalciferol kg^-1 . The use of 25-hydroxicholecalciferol tended (P = 0.052) to improve total born and influenced (P = 0.046) on number of born alive. Litter weight at birth was also increased (P = 0.01) by 25-hydroxicholecalciferol supplementation; 25-hydroxicholecalciferol supplementation and housing system (free-range with sunlight exposure) tended to increase weaning weight (P = 0.07) and litter daily gain (P = 0.051) during lactation. Exposure to sunlight and 25-hydroxicholecalciferol supplementation increased 25(OH)D₃ serum levels when compared with control treatment during gestation (136.95 vs. 113.92 ng mL^-1 ; P = 0.035) and lactation (120.29 vs. 88.93 ng mL^-1 ; P = 0.026). In conclusion, the association of 25-hydroxicholecalciferol supplementation with exposure to sunlight during gestation improved significantly 25(OH)D₃ serum levels and consequently performance traits in gestation and lactation.

The impact of dietary supplementation of arginine during gestation in a commercial swine herd: II. Offspring performance

Arginine (Arg) is an important amino acid of pig fetal development; however, whether Arg improves postnatal performance is ill-defined. Therefore, the influence of Arg supplementation at different gestational stages on offspring performance was evaluated in a commercial swine herd. Sows (n = 548) were allocated into 4, diet by stage of gestation treatments: Control (n = 143; 0% suppl. Arg), or dietary treatments supplemented with 1% L-Arg (free-base; Ajinomoto Animal Nutrition North America, Inc., Chicago, IL): from 15 to 45 d of gestation (n = 138; Early-Arg); 15 d of gestation to farrowing (n = 139; Full-Arg); and from day 85 of gestation to farrowing (n = 128; Late-Arg). All offspring were individually identified and weighed at birth; at weaning, a subset was selected for evaluation of carcass performance at market. All data were analyzed using birth weight (BiWt) and age as covariates. Wean weights (WW) and prewean (PW) ADG tended to increase (P = 0.06) in progeny from sows supplemented with Arg, as compared to progeny from Control sows. Preplanned contrast comparisons revealed an increased (P = 0.03) BiWt for pigs from sows receiving 1% L-Arg prior to day 45 of gestation (Early-Arg and Full-Arg; 1.38 kg/pig), as compared to pigs from sows not supplemented prior to day 45 of gestation (Control and Late-Arg; 1.34 kg/pig). No difference in BiWt was observed (1.36 kg/pig; P = 0.68) for Arg supplementation after day 85 of gestation (Full-Arg and Late-Arg), as compared to those not receiving Arg supplementation after day 85 (Control and Early-Arg); although WW and PW ADG were greater (P = 0.02), respectively. A 3.6% decrease (P = 0.05) in peak lean accretion ADG occurred when dams received 1% L-Arg prior to day 45 of gestation (Early-Arg and Full-Arg), however, no other significant differences were detected in finishing growth parameters or carcass characteristics (P ≥ 0.1). Pig mortality rates tended (P = 0.07) to decrease in progeny of dams supplemented Arg after day 85 (3.6%) compared to dams not provided additional Arg during late gestation (4.9%). Collectively, these data suggest that Arg provided during late gestation may improve WW and PW ADG, however, finishing performance was not affected. While Arg supplementation provided some moderate production benefits, further investigation is warranted to comprehensively understand the gestational timing and biological role of Arg supplementation during fetal and postnatal development in commercial production systems.

TRIENNIAL GROWTH SYMPOSIUM: THE NUTRITION OF MUSCLE GROWTH: Impacts of nutrition on the proliferation and differentiation of satellite cells in livestock species1,2

Nutrition and other external factors are known to have a marked effect on growth of skeletal muscle, modulated, at least in part, through effects on satellite cells. Satellite cells and their embryonic precursors play an integral role in both prenatal and postnatal skeletal muscle growth of mammals. Changes in maternal nutrition can impact embryonic muscle progenitor cells which ultimately impacts both prenatal and postnatal skeletal muscle development. Satellite cells are important in postnatal skeletal muscle growth as they support the hypertrophy of existing myofibers. Hypertrophy of existing fibers is the only mechanism of postnatal muscle growth because muscle fiber number is fixed at birth and fiber nuclei have exited the cell cycle. Because fiber nuclei do not divide, additional nuclei required for hypertrophy must be acquired from satellite cells. To date, little research has aimed at determining whether nutrition directly impacts satellite cell populations within skeletal muscle of livestock species. However, it is well established that nutrition alters circulating concentrations of various growth factors such as insulin-like growth factor 1, epidermal growth factor, hepatocyte growth factor, and fibroblast growth factor. Each of these different growth factors impacts satellite cell proliferation and/or activation, indicating that nutrition likely plays a large role in skeletal muscle growth through impacting the satellite cell pool in both prenatal and postnatal growth. The relationship among nutrition, growth factors, and satellite cells relative to skeletal muscle growth is an important area of research that warrants further consideration.

The effects of maternal dietary supplementation of cholecalciferol (vitamin D3) and 25(OH)D3 on sow and progeny performance

A total of 69 sows (DNA Line 200 × 400) and their progeny were used to determine if feeding a combination of vitamin D₃ and 25(OH)D₃ influences neonatal and sow vitamin D status, muscle fiber morphometrics at birth and weaning, and subsequent growth performance. Within 3 d of breeding, sows were allotted to one of three dietary treatments fortified with 1,500 IU/kg vitamin D₃ (CON), 500 IU/kg vitamin D₃ + 25 μg/kg 25(OH)D₃ (DL), or 1,500 IU/kg vitamin D₃ + 50 μg/kg 25(OH)D₃ (DH). When pigs were sacrificed at birth, there were no treatment effects for all fiber morphometric measures (P > 0.170), except primary fiber number and the ratio of secondary to primary muscle fibers (P < 0.016). Pigs from CON fed sows had fewer primary fibers than pigs from sows fed the DH treatment (P = 0.014), with pigs from sows fed DL treatment not differing from either (P > 0.104). Pigs from CON and DL fed sows had a greater secondary to primary muscle fiber ratio compared to pigs from DH sows (P < 0.022) but did not differ from each other (P = 0.994). There were treatment × time interactions for all sow and pig serum metabolites (P < 0.001). Therefore, treatment means were compared within the time period. At all time periods, sow serum 25(OH)D₃ concentrations differed for all treatments with the magnitude of difference largest at weaning (P < 0.011), where serum 25(OH)D₃ concentration was always the greatest when sows were fed the DH diet. At birth, piglets from DH fed sows had greater serum 25(OH)D₃ concentrations than piglets from sows fed the DL treatment (P = 0.003), with piglets from sows fed CON treatment not differing from either (P > 0.061). At weaning, serum concentrations of 25(OH)D₃ in piglets from all sow treatments were different (P < 0.001), with the greatest concentration in piglets from DH sows, followed by CON, and followed by DL. There were no treatment × time interactions for any of the metabolites measured in milk and no treatment or time main effects for 24,25(OH)₂D₃ concentration (P > 0.068). Colostrum collected within 12 h of parturition contained less (P = 0.001) 25(OH)D₃ than milk collected on day 21 of lactation. Regardless of time, concentrations of 25(OH)D₃ in milk were different (P < 0.030), with the largest 25(OH)D₃ concentration from DH fed sows, followed by DL, and then CON. In conclusion, combining vitamin D₃ and 25(OH)D₃ in the maternal diet improves the vitamin D status of the dam and progeny and it increases primary muscle fiber number at birth.

Vitamin D during pregnancy and offspring body composition: a prospective cohort study

BACKGROUND

Evidence regarding the association between gestational vitamin D status and offspring body composition during childhood is inconsistent. Therefore, we aimed to determine the association between maternal vitamin D and offspring lean and fat mass in the Vitamin D in Pregnancy birth cohort.

METHODS

Subjects were mother-child pairs recruited from the Australian-based Vitamin D in Pregnancy cohort study. Mothers were recruited before 16 weeks' gestation and provided a blood sample at both recruitment and at 28-32 weeks' gestation. Serum vitamin D [25(OH)D] was measured by radioimmunoassay (Tyne and Wear, UK). Offspring lean and fat mass were quantified by using dual-energy X-ray absorptiometry (GE Lunar Prodigy, Madison, WI, USA) at 11 years of age.

RESULTS

Median maternal 25(OH)D levels were 55.9 (42.2-73.3) and 56.1 (43.6-73.9) at recruitment and 28-32 weeks' gestation, respectively. Maternal smoking was identified as an effect modifier in the association between maternal vitamin D status at recruitment and offspring body composition. In smokers, but not non-smokers, serum 25(OH)D status at recruitment was negatively associated with offspring fat mass percentage and positively associated with lean mass (both p < 0.05). There was no association with 25(OH)D status at 28-32 weeks' gestation.

CONCLUSIONS

Maternal vitamin D status in early pregnancy, in smokers, is associated with offspring body composition. These important findings warrant confirmation in larger studies and trials.

Association Between Vitamin D Supplementation During Pregnancy and Offspring Growth, Morbidity, and Mortality: A Systematic Review and Meta-analysis

IMPORTANCE

Whether vitamin D supplementation during pregnancy is beneficial and safe for offspring is unclear.

OBJECTIVE

To systematically review studies of the effects of vitamin D supplementation during pregnancy on offspring growth, morbidity, and mortality.

DATA SOURCES

Searches of Medline, Embase, and the Cochrane Database of Systematic Reviews were conducted up to October 31, 2017. Key search terms were vitamin D, pregnancy, randomized controlled trials, and offspring outcomes.

STUDY SELECTION

Randomized clinical trials of vitamin D supplementation during pregnancy and offspring outcomes.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data, and the quality of the studies was assessed. Summary risk ratio (RR), risk difference (RD) or mean difference (MD), and 95% CI were calculated using fixed-effects or random-effects meta-analysis.

MAIN OUTCOMES AND MEASURES

Main outcomes were fetal or neonatal mortality, small for gestational age (SGA), congenital malformation, admission to a neonatal intensive care unit, birth weight, Apgar scores, neonatal 25-hydroxyvitamin D (25[OH]D) and calcium concentrations, gestational age, preterm birth, infant anthropometry, and respiratory morbidity during childhood.

RESULTS

Twenty-four clinical trials involving 5405 participants met inclusion criteria. Vitamin D supplementation during pregnancy was associated with a lower risk of SGA (RR, 0.72; 95% CI, 0.52 to 0.99; RD, -5.60%; 95% CI, -0.86% to -10.34%) without risk of fetal or neonatal mortality (RR, 0.72; 95% CI, 0.47 to 1.11) or congenital abnormality (RR, 0.94; 95% CI, 0.61 to 1.43). Neonates with prenatal vitamin D supplementation had higher 25(OH)D levels (MD, 13.50 ng/mL; 95% CI, 10.12 to 16.87 ng/mL), calcium levels (MD, 0.19 mg/dL; 95% CI, 0.003 to 0.38 mg/dL), and weight at birth (MD, 75.38 g; 95% CI, 22.88 to 127.88 g), 3 months (MD, 0.21 kg; 95% CI, 0.13 to 0.28 kg), 6 months (MD, 0.46 kg; 95% CI, 0.33 to 0.58 kg), 9 months (MD, 0.50 kg; 95% CI, 0.01 to 0.99 kg), and 12 months (MD, 0.32 kg; 95% CI, 0.12 to 0.52 kg). Subgroup analysis by doses showed that low-dose vitamin D supplementation (≤2000 IU/d) was associated with a reduced risk of fetal or neonatal mortality (RR, 0.35; 95% CI, 0.15 to 0.80), but higher doses (>2000 IU/d) did not reduce this risk (RR, 0.95; 95% CI, 0.59 to 1.54).

CONCLUSIONS AND RELEVANCE

Vitamin D supplementation during pregnancy is associated with a reduced risk of SGA and improved infant growth without risk of fetal or neonatal mortality or congenital abnormality. Vitamin D supplementation with doses of 2000 IU/d or lower during pregnancy may reduce the risk of fetal or neonatal mortality.

Prenatal vitamin D status and offspring's growth, adiposity and metabolic health: a systematic review and meta-analysis

In this systematic review and meta-analysis of observational studies, we aimed to estimate the associations between prenatal vitamin D status and offspring growth, adiposity and metabolic health. We searched the literature in human studies on prenatal vitamin D status and offspring growth in PubMed, up to July 2017. Studies were selected according to their methodological quality and outcomes of interest (anthropometry, fat mass and diabetes in offspring). The inverse variance method was used to calculate the pooled mean difference (MD) with 95 % CI for continuous outcomes, and the Mantel-Haenszel method was used to calculate the pooled OR with 95 % CI for dichotomous outcomes. In all, thirty observational studies involving 35 032 mother-offspring pairs were included. Vitamin D status was evaluated by circulating 25-hydroxyvitamin D (25(OH)D) level. Low vitamin D status was based on each study's cut-off for low 25(OH)D levels. Low prenatal vitamin D levels were associated with lower birth weight (g) (MD -100·69; 95 % CI -162·25, -39·13), increased risk of small-for-gestational-age (OR 1·55; 95 % CI 1·16, 2·07) and an elevated weight (g) in infant at the age of 9 months (g) (MD 119·75; 95 % CI 32·97, 206·52). No associations were observed between prenatal vitamin D status and other growth parameters at birth, age 1 year, 4-6 years or 9 years, nor with diabetes type 1. Prenatal vitamin D may play a role in infant adiposity and accelerated postnatal growth. The effects of prenatal vitamin D on long-term metabolic health outcomes in children warrant future studies.

The clinical use of vitamin D metabolites and their potential developments: a position statement from the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis (ESCEO) and the International Osteoporosis Foundation (IOF)

Several compounds are produced along the complex pathways of vitamin D3 metabolism, and synthetic analogs have been generated to improve kinetics and/or vitamin D receptor activation. These metabolites display different chemical properties with respect to the parental or native vitamin D3, i.e., cholecalciferol, which has been, so far, the supplement most employed in the treatment of vitamin D inadequacy. Hydrophilic properties of vitamin D3 derivatives facilitate their intestinal absorption and their manageability in the case of intoxication because of the shorter half-life. Calcidiol is a more hydrophilic compound than parental vitamin D3. Active vitamin D analogs, capable of binding the vitamin D receptor evoking vitamin D-related biological effects, are mandatorily employed in hypoparathyroidism and kidney failure with impaired 1α-hydroxylation. They have been shown to increase BMD, supposedly ameliorating calcium absorption and/or directly affecting bone cells, although their use in these conditions is jeopardized by the development of hypercalciuria and mild hypercalcemia. Further studies are needed to assess their overall safety and effectiveness in the long-term and new intermittent regimens, especially when combined with the most effective antifracture agents.

Moderately increased maternal dietary energy intake delays foetal skeletal muscle differentiation and maturity in pigs

OBJECTIVES

This study aimed to evaluate the effects of moderately increased maternal dietary energy intake during gestation on foetal skeletal muscle development and metabolism with pig as a model.

METHODS

Twelve primiparous purebred Large White sows (initial body weight 135.5 ± 1.6 kg) were allocated to one of two energy intake treatments: normal-energy-intake group (Con, 30.96 MJ DE/day) as recommended by the National Research Council (NRC; 2012) and high-energy-intake group (HE, 34.15 MJ DE/day). The nutritional treatments were introduced from mating to day 90 of gestation. On day 90 of gestation, foetuses were examined by morphological, biochemical and molecular analysis of the longissimus muscle. Umbilical vein serum hormones were measured.

RESULTS

Sow body weight was increased in HE group compared with Con group (P < 0.05), whereas foetal myofibre density was decreased (P < 0.05). Meanwhile, protein concentration, creatine kinase and lactate dehydrogenase activities and umbilical vein serum triiodothyronine (T3) concentration were decreased in HE foetuses (P < 0.05). Maternal HE diets decreased the mRNA abundance of muscle growth-related genes, myosin heavy-chain (MYH/MyHC) genes (MYH2 and MYH1) and insulin-like growth factor 1 and insulin growth factor-binding protein 5 (P < 0.05). Furthermore, the protein expressions of myogenic differentiation factor 1, myogenin and fast-MyHC isoforms were reduced in HE foetuses (P < 0.05).

CONCLUSION

Our results suggest that moderately increased maternal dietary energy intake delays the differentiation and maturation in skeletal muscle of the foetus on day 90 of gestation.

Effect of vitamin D status improvement with 25-hydroxycholecalciferol on skeletal muscle growth characteristics and satellite cell activity in broiler chickens

Skeletal muscle satellite cells (SC) play a critical role in the hypertrophic growth of postnatal muscle. Increases in breast meat yield have been consistently observed in broiler chickens fed 25-hydroxycholecalciferol (25OHD3), but it is unclear whether this effect is mediated by SC. Thus, our objective was to determine the effect of vitamin D status improvement by replacing the majority of dietary vitamin D3 (D3) with 25OHD3 on SC activity and muscle growth characteristics in the pectoralis major (PM) and the biceps femoris (BF) muscles. Day-old, male Ross 708 broiler chickens (n = 150) were fed 1 of 2 corn and soybean meal-based diets for 49 d. The control diet (CTL) contained 5,000 IU D3 per kg of diet and the experimental diet (25OHD3) contained 2,240 IU D3 per kg of diet + 2,760 IU 25OHD3 per kg of diet. Ten birds per treatment were harvested every 7 d. Two hours before harvest, birds were injected intraperitoneally with 5'-bromo-2'deoxyuridine (BrdU) to label mitotically active cells. Blood was collected from each bird at harvest to measure circulating concentrations of 25OHD3, a marker of vitamin D status. The PM and BF muscles were weighed and processed for cryohistological determination of skeletal muscle fiber cross-sectional area, enumeration of Myf-5+ and Pax7+ SC, and mitotically active (BrdU+) SC using immunofluorescence microscopy. Circulating 25OHD3 concentrations were greater in 25OHD3-fed birds on d 7, 14, 21, 28, 35, 42, and 49 when compared with CTL (P < 0.001). Growth performance and feed efficiency did not differ among dietary treatments (P > 0.10). Improved vitamin D status as a result of feeding 25OHD3 increased the number of mitotically active (Pax7+;BrdU+) SC (P = 0.01) and tended to increase the density of Pax7+ SC (P = 0.07) in the PM muscles of broilers on d 21 and 35, respectively. Broiler chickens fed 25OHD3 also tended to have greater Myf-5+ SC density (P = 0.09) on d 14, greater total nuclear density (P = 0.05) on d 28, and a greater muscle fiber cross-sectional area (P = 0.09) on d 49 in their PM muscles compared with CTL birds. Collectively, these results suggest that improvement of vitamin D status by replacing the majority of D3 in the diet with 25OHD3 can stimulate SC activity in the predominantly fast-twitch PM muscle and provide evidence toward understanding the mechanism behind previously observed increases in breast meat yield in 25OHD3-fed commercial broiler chickens.

Triennial Growth Symposium--A role for vitamin D in skeletal muscle development and growth

Although well known for its role in bone development and mineral homeostasis, there is emerging evidence that vitamin D is capable of functioning as a regulator of skeletal muscle development and hypertrophic growth. This review will focus on the relatively limited body of evidence regarding the impact of vitamin D on prenatal development and postnatal growth of skeletal muscle in meat animal species. Recent evidence indicating that improvement of maternal vitamin D status through dietary 25-hydroxycholecalciferol supplementation can positively affect fetal skeletal muscle fiber number and myoblast activity in swine as well as work demonstrating that posthatch vitamin D status enhancement stimulates a satellite cell-mediated skeletal muscle hypertrophy response in broiler chickens is discussed. The relative lack of information regarding how and when to best supply dietary vitamin D to promote optimal prenatal development and postnatal growth of skeletal muscle provides an exciting field of research. Expansion of knowledge in this area will ultimately improve our ability to efficiently and effectively produce the livestock required to meet the increasing worldwide demand for meat products.