Studies have attempted to demonstrate the benefits of silicon on bone health using a wide range of Si amounts—provided in the diet or through supplementation—and several different animal species. Previous studies in humans have also demonstrated a positive correlation between Si intake and bone health measures. The aim of the current review is to determine the effective levels of Si intake or supplementation that influence bone health to better inform future study designs and guidelines. Articles were identified using one of two search terms: “silicon AND bone” or “sodium zeolite A AND bone”. Articles were included if the article was a controlled research study on the effect of Si on bone health and/or mineral metabolism and was in English. Articles were excluded if the article included human subjects, was in vitro, or studied silica grafts for bone injuries. Silicon type, group name, Si intake from diet, Si supplementation amount, animal, and age at the start were extracted when available. Dietary Si intake, Si supplementation amount, and the amount of Si standardized on a kg BW basis were calculated and presented as overall mean ± standard deviations, medians, minimums, and maximums. Studies that left out animal weights, amount of food or water consumed, or nutrient profiles of the basal diet were excluded from these calculations. Standardized Si intakes ranged from 0.003 to 863 mg/kg BW, at times vastly exceeding current human Si intake recommendations (25 mg/d). The lack of data provided by the literature made definitively determining an effective threshold of supplementation for skeletal health difficult. However, it appears that Si consistently positively influences bone and mineral metabolism by around 139 mg Si/kg BW/d, which is likely unfeasible to attain in humans and large animal species. Future studies should examine this proposed threshold more directly and standardize supplemental or dietary Si intakes to kg BW for better study replication and translation.

Because leg injuries produce welfare concerns and impact production for broilers, numerous interventions have been suggested as potential solutions. One mineral which may affect bone quality is silicon. The objective of this study was to determine if supplementing bioavailable silicon could affect bone morphology, mineralization, and strength without negatively influencing welfare and meat quality. Male broilers were raised from d 1 after hatching until 42 d of age and randomly assigned to treatment groups for silicon supplementation in water: Control (no supplement, C; n = 125), Normal (0.011 ml supplement/kg bodyweight, N; n = 125) and High (0.063 ml supplement/kg bodyweight, H; n = 125). Toe damage, footpad dermatitis, hock burn, and keel blisters were assessed on d 42. Blood samples were collected from wing veins for serum osteocalcin, pyridinoline cross-links, and mineral analysis. Clinical QCT scans and analysis were conducted immediately before four-point bending tests of tibias. Texture analysis was performed on cooked fillets. Silicon supplementation tended to increase daily water consumption in N and H as compared to C (P = 0.07). Footpad dermatitis and hock burn scores were higher in H than in N or C (P < 0.05 for both comparisons). Supplementation altered serum minerals (P < 0.001), but bone density, morphology, and strength measures were similar among groups. The highest level of supplementation in the current study on a kg bodyweight basis was above recommended intakes but below previous amounts demonstrating silicon’s positive influence on bone, indicating that previously suggested minimum thresholds need to be reevaluated. Factors such as growth rate and mechanical loading likely play a greater role in developing bone quality than trying to supplement on top of good basic nutrition alone.

Owing to selection for rapid growth and heavy muscle, bone deformities and injuries in broiler chickens are common and present a welfare concern. Recently, clinical quantitative computed tomography scans (QCTs) have been used for laying hens with significant, strong correlations between QCT-generated bone mineral content (BMC), bone ash, and analytical calcium. The objectives of this study were to determine if QCT-generated bone mineral density of tibias and femurs correlated to fat-free ash and if analytical Ca could be correlated to bone ash and digitally calculated density in immature broilers. Male broilers (Ross 708, n = 125) were raised from day 1 after hatching, and at 42 D, right leg quarters were collected from 50 randomly selected birds and frozen at −20°C until analysis. Leg quarters were scanned with muscle and feathers intact and arranged in rows on plexiglass, and each QCT included a solid Ca hydroxyapatite phantom. Tibias and femurs were removed from leg quarters after autoclaving, ashed, and weighed. Pearson's correlation analysis was conducted to understand the association between analytical bone ash and QCT BMC while paired t tests determined the amount of difference between QCT BMC and ash. Ash weight was strongly correlated to QCT BMC in both the femur (R = 0.86, P < 0.001) and the tibia (R = 0.91, P < 0.001). The average difference between the amount of actual ash weighed and BMC calculated from the QCT was 0.03 ± 0.22 g (P = 0.3) for the femur and 0.04 ± 0.22 g (P = 0.2) for the tibia. This study confirms that this technique can supply invaluable skeletal health information without sacrificing birds.

Undernutrition induced growth restriction in early life increases the risk of chronic disease in adulthood. While metabolic impairments have been observed, few studies have characterized the gut microbiome and gut-liver metabolome profiles of growth restricted animals during early-to-mid-life development. To induce growth restriction, mouse offspring were either born to gestational undernutrition (GUN) or suckled from postnatal undernutrition (PUN) dams fed a protein-restricted diet (8% protein) or control diet (CON; 20% protein) until weaning at postnatal age of 21 days (PN21). At PN21, all mice were fed the CON diet until adulthood (PN80). Livers were collected at PN21 and PN80, and fecal samples were collected weekly for gut microbiome and metabolome analyses. PUN mice exhibited the most alterations in gut microbiome and gut and liver metabolome compared to CON. These mice had altered fecal microbial Beta-Diversity (p=0.001) and exhibited higher proportions of Bifidobacteriales (Linear Mixed Model (LMM) p=7.158x10^-6), Clostridiales (p=1.459x10^-5), Erysipelotrichales (p=0.0003) and lower Bacteroidales (p=4.121x10^-5). PUN liver and fecal metabolome had a reduced total bile acid pool (p<0.01), as well as lower Riboflavin (p=0.003), amino acids (i.e., methionine (p=0.0018), phenylalanine (p=0.0015), and tyrosine (p=0.0041)), and higher excreted total peptides (LMM p=0.0064), dipeptides (p=0.001), and tripeptides (p=0.0123) compared to CON. PUN also had abnormally reduced Epiandrosterone (p=0.02) at PN80. PUN liver and fecal metabolome varied in specific acylcarnitines: higher liver oleoyl-L-carnitine (p=0.0038) and palmitoylcarnitine (p=0.0096) vs. CON at PN21, which recovered at PN80. However, PUN also had higher fecal R-ButyrylCarnitine (p=0.0125) through adulthood, despite refeeding. Overall, protein restriction during lactation permanently alters the gut microbiome into adulthood. While the liver bile acids, amino acids, and acylcarnitines recovered, the fecal peptides and microbiome remained permanently altered into adulthood, indicating that inadequate protein intake in a specific time frame in early life can have an irreversible impact on the microbiome and fecal metabolome.

Arena polo is surging in popularity, but limited information exists on the physiological demands of polo. The goal of this study was to document the oxygen consumption (VO₂), ventilation (VE), and respiratory exchange ratio (RER) in conjunction with heart rate (HR) involved in arena polo to better inform players of the physical requirements of participation. Cardiorespiratory responses were measured using a portable telemetric oxygen analyzer coupled with a heart rate monitor on five female arena polo players. Peak aerobic capacity of each player was determined on a treadmill in a laboratory setting. Data were recorded on each player during designated sessions which included a prescribed and free choice warmup, mock gameplay (Chukker), and five‐minute recovery. Descriptive statistics for each variable (Mean ± SE) were calculated for each period. A one‐way ANOVA with repeated measures was performed to determine differences among periods. Chukker produced the highest cardiorespiratory responses out of all the periods (P < 0.001) with 89 ± 1% HR_peak and 62 ± 2% VO_2peak, except for RER which was highest during recovery (0.88 ± 0.01, P < 0.001). As evidenced by this study, arena polo constitutes intense exercise comparable to traditional sports above warmup and recovery.