Effect of protein level and methionine supplementation on dairy cows during the transition period.

Cows experience a significant negative protein balance during the first 30 d of lactation. Given the functional effects of AA on health, especially in challenging periods such as calving, higher levels of protein and specific AA in the diet may act to improve health and feed intake. The response of dairy cows to 3 protein supplementation strategies during the transition period and through the first 45 d in milk was evaluated. The final data set had 39 Holstein cows blocked based on parity (primiparous vs. multiparous) and expected calving and randomly assigned within each block to one of 3 dietary treatments: low protein (LP), high protein (HP), or high protein plus rumen-protected methionine (HPM). Treatments were offered from d -18 ± 5 to 45 d relative to parturition. Pre- and postpartum diets were formulated for high metabolizable protein (MP) supply from soybean meal, and HP and HPM provided higher MP balance than LP. Preplanned contrasts were LP versus HP+HPM and HP versus HPM. Significance was declared at P ≤ 0.05 and trends at 0.05

Effects of propionate concentration on short-term metabolism in liver explants from dairy cows in the postpartum period.

Our objective was to determine the temporal effects of increasing supply of propionate on propionate metabolism in liver tissue of dairy cows in the postpartum (PP) period. A total of 6 dairy cows [primiparous: n = 3, 9.00 ± 1.00 d PP (mean ± SD) and multiparous: n = 3; 4.67 ± 1.15 d PP] were biopsied for liver explants in a block-design experiment. Explants were treated with 3 concentrations of [13C3]sodium propionate of 1, 2, or 4 mM. Explants were incubated in 2 mL of Medium 199 supplemented with 1% BSA, 0.6 mM oleic acid, 2 mM sodium l-lactate, 0.2 mM sodium pyruvate, and 0.5 mMl-glutamine at 38°C and sampled at 0.5, 15, and 60 min. Increasing the concentration of [13C3]propionate increased total 13C% enrichment of propionyl coenzyme A (CoA), succinate, fumarate, malate, and citrate with time. Concentration of propionate did not affect total 13C% enrichment of hepatic glucose or acetyl CoA, but total 13C% enrichment increased with time for hepatic glucose. The 13C labeling from propionate was incorporated into acetyl CoA, but increased concentrations of propionate did not result in greater labeling of acetyl CoA. However, increases in 13C% enrichment of [M+4]citrate and [M+5]citrate concentrations of [13C3]propionate indicate propionate conversion to acetyl CoA and subsequent entry of acetyl CoA into the tricarboxylic acid cycle in dairy cows in the PP period. This research presents evidence that despite an increase in hepatic acetyl CoA concentration and general consensus on the upregulation of gluconeogenesis of dairy cows during the PP period, carbon derived from propionate contributes to the pool of acetyl CoA, which increases as concentration of propionate increases, in addition to stimulating oxidation of acetyl CoA from other sources. Because of the hypophagic effects of propionate, but importance of propionate as a glucose precursor, a balance of propionate supply to dairy cows could lead to improvements in dry matter intake, and subsequently, health and production in dairy cows.

The effects of supplementation with a blend of cinnamaldehyde and eugenol on feed intake and milk production of dairy cows.

Plant extracts (PE) are naturally occurring chemicals in plants, and many of these molecules have been reported to influence production efficiency of dairy and beef animals. Two experiments were conducted to determine the effect of a PE additive (CE; an encapsulated blend of cinnamaldehyde and eugenol) on the milk production performance of lactating dairy cows across a range of doses. In experiment 1, 32 Holstein multi- and primiparous dairy cows in mid-lactation were assigned to no additive or supplementation with CE (350mg/d; n=16 cows/treatment) for 6 wk. In experiment 2, 48 Holstein multi- and primiparous dairy cows were assigned to no additive or supplementation with CE (200, 400, or 600mg/d; n=12 animals/treatment) for 8 wk. A 1-wk covariate period was included in both experiments. In both experiments, individual dry matter intake (DMI), milk production, milk composition, and somatic cell count were recorded daily. In experiment 1, CE was associated with an increase in DMI in both parity groups but an increase in milk production of multiparous cows only. In experiment 2, milk yield of multiparous cows was decreased at the 2 highest doses, whereas milk yield of primiparous cows was increased at the low and high doses of CE. These responses were accompanied by similar changes in DMI; therefore, CE did not affect feed efficiency. We observed no effect of CE on SCC or milk composition; however, treatment by parity interactions were detected for each of these variables that have not been described previously. Based on the results of these experiments, we conclude that a blend of cinnamaldehyde and eugenol can increase DMI and milk production in lactating dairy cows. In addition, environmental factors appear to influence the response to CE, including dose and parity, and these should be explored further.

Impact of vitamin D supplementation during a resistance training intervention on body composition, muscle function, and glucose tolerance in overweight and obese adults.

BACKGROUND & AIMS: The impact of vitamin D supplementation in overweight and obese adults during resistance training on body composition, muscle function, and glucose tolerance was investigated. METHODS: Twenty-three overweight and obese (age: 26.1±4.7 y; BMI: 31.3±3.2 kg/m(2); 25-hydroxyvitamin D: 19.3±7.2 ng/mL) adults were recruited for participation in a double-blind, placebo-controlled trial. Participants were randomly divided into vitamin D (VitD, 4000 IU/d; 5 females, 5 males) and placebo (PL; 7 females, 6 males) groups. Both groups completed 12 weeks of resistance training. 25-hydroxyvitamin D, parathyroid hormone, body composition, and glucose tolerance were assessed at baseline and 12 weeks. Muscle function (strength and power) was assessed at baseline, 4, 8, and 12 weeks. RESULTS: During the intervention, 25-hydroxyvitamin D increased and parathyroid hormone decreased in the VitD group (P<0.05). Peak power was significantly increased at 4 weeks in the VitD group only (P<0.05). Regression analysis revealed an inverse association between the change in 25-hydroxyvitamin D with the change in waist-to-hip ratio (R(2)=0.205, P=0.02). No other improvements were observed with supplementation. CONCLUSIONS: Vitamin D supplementation in overweight and obese adults during resistance training induced an early improvement in peak power, and elevated vitamin D status was associated with reduced waist-to-hip ratio. CLINICAL TRIAL REGISTRATION NUMBER: NCT01199926.

Vitamin D supplementation during exercise training does not alter inflammatory biomarkers in overweight and obese subjects.

The purpose of this study was to examine the effects of vitamin D supplementation on inflammatory biomarkers in overweight and obese adults participating in a progressive resistance exercise training program. Twenty-three (26.1 ± 4.7 years) overweight and obese (BMI 31.3 ± 3.2 kg/m2) adults were randomized into a double-blind vitamin D supplementation (Vit D 4,000 IU/day; female 5, male 5) or placebo (PL, female 7; male 6) intervention trial. Both groups performed 12 weeks (3 days/week) of progressive resistance exercise training (three sets of eight exercises) at 70-80% of one repetition maximum. Whole-blood lipopolysaccharide (LPS)-stimulated tumor necrosis factor (TNF) α production as well as circulating C-reactive protein (CRP), TNFα, interleukin 6 (IL-6), and alanine aminotransferase (ALT) were assessed at baseline and after the 12-week intervention. No main effects of group or time were detected for circulating CRP, TNFα, IL-6, and ALT. As expected, when PL and Vit D groups were combined, there was a significant correlation between percent body fat and CRP at baseline (r = 0.45, P = 0.04), and between serum 25OHD and CRP at 12 weeks (r = 0.49, P = 0.03). The PL group had a significant increase in 25 µg/ml LPS + polymixin B-stimulated TNFα production (P = 0.04), and both groups had a significant reduction in unstimulated TNFα production (P < 0.05) after the 12-week intervention. Vitamin D supplementation in healthy, overweight, and obese adults participating in a resistance training intervention did not augment exercise-induced changes in inflammatory biomarkers.

Modified soybean affects cholesterol metabolism in rats similarly to a commercial cultivar.

The consumption of soy protein lowers blood cholesterol in humans and animals. Breeding may alter the physiological effects of soybeans, such as its cholesterol-lowering property. Our hypothesis is that breeding affects the hypocholesterolemic effect of soy by modulating the expression of key hepatic enzymes related to cholesterol and bile acid biosynthesis, as well as altering fecal neutral and acidic steroid excretion. Therefore the aim of this study was to evaluate the effect of a new Brazilian soybean cultivar (UFV-116), lacking lipoxygenases 2 and 3, compared with a commercial cultivar (OCEPAR-19), on 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) and cholesterol 7α-hydroxylase (CYP7A) mRNA expression and fecal steroid output in rats. Thirty-six male rats were fed UFV-116, OCEPAR-19, or casein as the protein source, with or without addition of dietary cholesterol (0.25%). Blood and liver cholesterol, HMGR and CYP7A mRNA abundance, and fecal excretion of steroids were measured. Blood and liver cholesterol levels were lowered by both soybean cultivars, with and without cholesterol, but UFV-116 was more effective when included in the cholesterol-free diet. Both soy diets promoted lower levels of HMGR mRNA, higher levels of CYP7A mRNA, and higher excretion of fecal secondary bile acids. There was higher fecal neutral steroid output when cholesterol was added to all diets. These data show that both soybean cultivars acted similarly in lowering serum and hepatic cholesterol; therefore, breeding did not affect the hypocholesterolemic effect of the new cultivar.

Vitamin D: emerging new roles in insulin sensitivity.

The growing incidence of prediabetes and clinical type 2 diabetes, in part characterised by insulin resistance, is a critical health problem with consequent devastating personal and health-care costs. Vitamin D status, assessed by serum 25-hydroxyvitamin D levels, is inversely associated with diabetes in epidemiological studies. Several clinical intervention studies also support that vitamin D, or its active metabolite 1,25-dihydroxyvitamin D (1,25(OH)2D), improves insulin sensitivity, even in subjects with glucose metabolism parameters classified within normal ranges. The mechanisms proposed which may underlie this effect include potential relationships with improvements in lean mass, regulation of insulin release, altered insulin receptor expression and specific effects on insulin action. These actions may be mediated by systemic or local production of 1,25(OH)2D or by suppression of parathyroid hormone, which may function to negatively affect insulin sensitivity. Thus, substantial evidence supports a relationship between vitamin D status and insulin sensitivity; however, the underlying mechanisms require further exploration.

Effects of atorvastatin on lipid metabolism in normolipidemic and hereditary hyperlipidemic, non-laying hens.

As a result of a hereditable point mutation in the oocyte very low density lipoprotein (VLDL) receptor, sexually mature restricted ovulator (RO) female chickens (Gallus gallus), first described as a non-laying strain, exhibit endogenous hyperlipidemia and develop atherosclerotic lesions. In a 20-day study, RO hens and their normolipidemic (NL) siblings were fed either a control diet, or the control diet supplemented with 0.06% atorvastatin (AT), a potent 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR) inhibitor. Compared to NL hens, RO birds exhibited greatly elevated baseline plasma total cholesterol (CHOL) and triglyceride (TG) concentrations (1.56 vs. 4.55 g/l and 30.7 vs. 138.4 g/l, respectively). AT attenuated plasma CHOL and TG concentrations by 60.3% and 70.1%, respectively, in NL hens and by 45.1% and 34.3%, respectively, in RO hens. Messenger RNA levels of several key genes involved in hepatic VLDL assembly were suppressed in RO vs. NL hens, but were unaffected by AT. In contrast, AT elevated liver HMGR mRNA levels in NL and RO birds, but only NL hens exhibited an AT-associated increase in hepatic HMGR immunoreactive protein levels. Down-regulation of HMGR gene expression due to higher baseline levels of circulating CHOL may explain why RO birds responded less robustly than NL hens to AT administration.