Relationship between protein molecular structural makeup and metabolizable protein supply to dairy cattle from new cool-season forage corn cultivars.

Protein solubility, ruminal degradation and intestinal digestibility are strongly related to their inherent molecular makeup. This study was designed to quantitatively evaluate protein digestion in the rumen and intestine of dairy cattle, and estimate the content of truly metabolizable protein (MP) in newly developed cool-season forage corn cultivars. The second objective was to quantify protein inherent molecular structural characteristics using advance molecular spectroscopic technique (FT/IR-ATR) and correlate it to protein metabolic characteristics. Six new cool-season corn cultivars, including 3 Pioneer (PNR) and 3 Hyland (HL), coded as PNR-7443R, PNR-P7213R, PNR-7535R, HL-SR06, HL-SR22, HL-BAXXOS-RR, were evaluated in the present study. The metabolic characteristics, MP supply to dairy cattle, and energy synchronization properties were modeled by two protein evaluation models, namely, the Dutch DVE/OEB system and the NRC-2001 model. Both models estimated significant (P<0.05) differences in contents of microbial protein (MCP) synthesis and truly absorbable rumen undegraded protein (ARUP) among the cultivars. The NRC-2001 model estimated significant (P<0.05) differences in MP content and degraded protein balance (DPB) among the cultivars. The contents MCP, ARUP and MP were higher (P<0.05) for cultivar HL-SR06, resulting in the lowest (P<0.05) DPB. However, none of the cultivars reached the optimal target hourly effective degradability ratio [25gNg/kg organic matter (OM)], demonstrating N deficiency in the rumen. There were non-significant differences among the cultivars in molecular-spectral intensities of protein. The amide I/II ratio had a significant correlation with ARUP (r=-0.469; P<0.001) and absorbable endogenous protein (AECPNRC) (P<0.001; r=0.612). Similarly, amide-II area had a weak but significant correlation (r=0.299; P<0.001) with RUP and ARUP, and with AECPNRC (P<0.001; r=0.411). Except total digestible nutrients and AECPNRC, the amide-I area did not show significant correlations with DVE/OEB and NRC predicted protein fractions. This study shows that molecular spectroscopy can be potentially used as a rapid tool to quantify protein molecular makeup and screen the protein nutritive value of forage corn.

Characterizations of structural, biochemical, and nutritive profiles in silage among cool-season corn cultivars in relation to heat units (aCHU, dCHU) with curvilinear response and multivariate analyses.

Molecular spectroscopy is able to reveal structural features of biomaterials. Corn grown in Canadian prairies is known as cool-season corn, which is different from warm-season corn varieties. To our knowledge, to date, there has been no study on the magnitude difference in structure on a molecular basis among cultivars, no study on biochemical and nutritive profiles associated with heat unit, and no study on how heat unit affects the molecular structure and biochemical and nutritive profiles. This study investigates how corn varieties grown in cooler climates are affected by crop heat units (CHU) in relation to molecular spectral profiles, nutrient storage, biochemical composition, and nutritive value of silage among different cool-season corn cultivars. Corn cultivars (Pioneer and Dekalb) were from seven farm locations, and samples were analyzed for major nutrients (digestible and metabolic energy and protein). The Fourier transform infrared (FT/IR) spectroscopic technique was applied to understand and differentiate molecular structural spectral profiles in silage. A correlation (P < 0.05) of CHU with some nutrients (mean ± SD, %DM) (CP, 8.1 ± 1.3, r = 0.56; NDF, 56.3 ± 3.5, r = -0.54; ADF, 33.6 ± 2.3, r = -0.71; NDICP, 1.6 ± 0.4, r = -0.66; SCP, 4.2 ± 1.3, r = 0.61), protein and carbohydrate fractions (mean ± SD, %DM) (PB1 (= fast degradable protein fraction), 1.3 ± 0.4, r = 0.54; PB3 (= slowly degradable protein fraction), 1.5 ± 0.4, r = -0.74; CB2 (= medium degradable carbohydrate fraction), 45.1 ± 2.8, r = -0.65; CB3 (= slowly degradable carbohydrate fraction), 13.9 ± 0.9, r = -0.54) and intestinal availability of ruminally degraded fractions (mean ± SD, %DM) (rdPB1, 1.1 ± 0.3, r = 0.54; rdPB3, 1.0 ± 0.3, r = -0.74; RDP, 6.6 ± 1.2, r = 0.59; rdCB2, 40.0 ± 2.5, r = -0.65; rdCB3, 8.9 ± 0.6, r = 0.54; RDCHO, 50.1 ± 2.9, r = -0.65) was found contentious. Molecular spectral data indicated many similarities and few differences among the cultivars. However, CHU correlated (r = -0.4, P < 0.05) with molecular spectral intensity ratio of carbohydrate to amide I. This result indicates that molecular structural differences may be influenced by epiphytic bacterial compounds. Cool corn cultivars were grown acceptably well in cooler dry climates, and those silages had acceptable nutrient levels for cattle. Cultivars that reached target CHU were found to be optimal in nutrient and energy synchronization aspect.

Molecular structure, chemical and nutrient profiles, and metabolic characteristics of the proteins and energy in new cool-season corn varieties harvested as fresh forage for dairy cattle.

To our knowledge, no previous research exists concerning the molecular structure and metabolic characteristics of the proteins and energy that new cool-season corn varieties provide for dairy cattle. The objectives of this study were to identify the differences in the molecular structures of proteins among several new cool-season corn varieties [Pioneer P7443R, Pioneer P7213R, Pioneer P7535R (Pioneer Hi-Bred International Inc., Johnston, IA), Hyland Baxxos RR, Hyland SR22, and Hyland SR06 (Hyland Seeds, Blenheim, ON, Canada)] using Fourier transform infrared attenuated total reflectance (FT/IR-ATR) molecular spectroscopy, and to determine the nutrient profile and supply that each variety provided for dairy cattle. The protein molecular structure studies showed that the amide I to amide II ratio ranged from 1.09 to 1.66 and that the α-helix to ß-sheet ratio ranged from 0.95 to 1.01 among the new cool-season corn varieties. Energy content was significantly different among the new varieties. We found significant differences in the protein and carbohydrate subfractions and in the ruminal degradation kinetics of the organic matter, crude protein, starch, and neutral detergent fiber of the new varieties. The new varieties had similar estimated intestinal digestibilities for rumen undegraded crude protein. However, the new varieties had significant differences in predicted total truly absorbable protein, ranging from 39 to 57 g/kg of dry matter, indicating that these newly developed varieties are satisfactory sources of truly absorbed protein for dairy cattle. Further study on the molecular structure profiles of cool-season corn in relation to its nutrient utilization and availability in dairy cattle is necessary.

Evaluation of the feed value for ruminants of blends of corn and wheat distillers dried grains.

Recently, biofuel processing has produced a large amount of biofuel coproducts. However, to date, there is little information on the metabolic characteristics of proteins and energy in biofuel coproduct-based rations. The objective of this study was to study the metabolic characteristics of proteins and energy in biofuel coproduct-based rations in terms of (1) chemical and nutrient profiles, (2) protein and carbohydrate subfraction associated with various degradation rate, (3) rumen and intestinal degradation and digestion kinetics, and (4) metabolic characteristics of proteins. Two sources of grain corn were mixed with two sources of biofuel coproducts (wheat-based dried distillers grains with solubles, wDDGS) in ratios of 100:0, 75:25, 50:50, and 25:75%. The study revealed that increasing the biofuel coproduct inclusion level increased most of the nutritional components linearly (P < 0.05) except starch, which linearly decreased. With increasing biofuel coproduct inclusion level, the rumen degradation rate and the effective degradability of organic matter were not affected (P > 0.05), but the effective degradability of starch was decreased (P < 0.05). Effective degradation of crude protein and neutral detergent fiber as well as predicted truly absorbed protein supply in the small intestine and degraded protein balance were increased (P < 0.05). In conclusion, the inclusion of the biofuel coproduct up to 25-50% in rations improved potential nitrogen and energy synchronization for microbial growth and improved truly absorbable protein supply to the small intestine, without altering energy value.

Univariate and multivariate molecular spectral analyses of lipid related molecular structural components in relation to nutrient profile in feed and food mixtures.

The objectives of this study were (i) to determine lipid related molecular structures components (functional groups) in feed combination of cereal grain (barley, Hordeum vulgare) and wheat (Triticum aestivum) based dried distillers grain solubles (wheat DDGSs) from bioethanol processing at five different combination ratios using univariate and multivariate molecular spectral analyses with infrared Fourier transform molecular spectroscopy, and (ii) to correlate lipid-related molecular-functional structure spectral profile to nutrient profiles. The spectral intensity of (i) CH(3) asymmetric, CH(2) asymmetric, CH(3) symmetric and CH(2) symmetric groups, (ii) unsaturation (CC) group, and (iii) carbonyl ester (CO) group were determined. Spectral differences of functional groups were detected by hierarchical cluster analysis (HCA) and principal components analysis (PCA). The results showed that the combination treatments significantly inflicted modifications (P<0.05) in nutrient profile and lipid related molecular spectral intensity (CH(2) asymmetric stretching peak height, CH(2) symmetric stretching peak height, ratio of CH(2) to CH(3) symmetric stretching peak intensity, and carbonyl peak area). Ratio of CH(2) to CH(3) symmetric stretching peak intensity, and carbonyl peak significantly correlated with nutrient profiles. Both PCA and HCA differentiated lipid-related spectrum. In conclusion, the changes of lipid molecular structure spectral profiles through feed combination could be detected using molecular spectroscopy. These changes were associated with nutrient profiles and functionality.

A pulse-based diet is effective for reducing total and LDL-cholesterol in older adults.

Our purpose was to determine the effects of a pulse-based diet in individuals 50 years or older for reducing CVD risk factors. A total of 108 participants were randomised to receive pulse-based foods (two servings daily of beans, chickpeas, peas or lentils; about 150 g/d dry weight) or their regular diet for 2 months, followed by a washout of 1 month and a cross-over to the other diet for 2 months. Anthropometric measures, body composition and biochemical markers (i.e. serum LDL-cholesterol (LDL-C), as the primary outcome, and other lipids, glucose, insulin and C-reactive protein) were assessed before and after each diet phase. A total of eighty-seven participants (thirty males and fifty-seven females; 59·7 (sd 6·3) years, body mass 76 (sd 16) kg) completed the study. Compared with the regular diet, the pulse-based diet decreased total cholesterol by 8·3 % (pulse, 4·57 (sd 0·93) to 4·11 (sd 0·91) mmol/l; regular, 4·47 (sd 0·94) to 4·39 (sd 0·97) mmol/l; P < 0·001) and LDL-C by 7·9 % (pulse, 2·93 (sd 0·84) to 2·55 (sd 0·75) mmol/l; regular, 2·96 (sd 0·86) to 2·81 (sd 0·83) mmol/l; P = 0·01). In a sub-analysis of individuals with high lipid levels at baseline (twenty individuals with high cholesterol), the pulse-based diet reduced cholesterol by 6 % compared with the regular diet (pulse, 5·62 (sd 0·78) to 5·26 (sd 0·68) mmol/l; regular, 5·60 (sd 0·91) to 5·57 (sd 0·85) mmol/l; P = 0·05). A pulse-based diet is effective for reducing total cholesterol and LDL-C in older adults and therefore reduces the risk of CVD.

Infusion of sodium bicarbonate in experimentally induced metabolic acidosis does not provoke cerebrospinal fluid (CSF) acidosis in calves.

In a crossover study, 5 calves were made acidotic by intermittent intravenous infusion of isotonic hydrochloric acid (HCl) over approximately 24 h. This was followed by rapid (4 h) or slow (24 h) correction of blood pH with isotonic sodium bicarbonate (NaHCO(3)) to determine if rapid correction of acidemia produced paradoxical cerebrospinal fluid (CSF) acidosis. Infusion of HCl produced a marked metabolic acidosis with respiratory compensation. Venous blood pH (mean ± S(x)) was 7.362 ± 0.021 and 7.116 ± 0.032, partial pressure of carbon dioxide (Pco(2), torr) 48.8 ± 1.3 and 34.8 ± 1.4, and bicarbonate (mmol/L), 27.2 ± 1.27 and 11 ± 0.96; CSF pH was 7.344 ± 0.031 and 7.240 ± 0.039, Pco(2) 42.8 ± 2.9 and 34.5 ± 1.4, and bicarbonate 23.5 ± 0.91 and 14.2 ± 1.09 for the period before the infusion of hydrochloric acid and immediately before the start of sodium bicarbonate correction, respectively. In calves treated with rapid infusion of sodium bicarbonate, correction of venous acidemia was significantly more rapid and increases in Pco(2) and bicarbonate in CSF were also more rapid. However, there was no significant difference in CSF pH. After 4 h of correction, CSF pH was 7.238 ± 0.040 and 7.256 ± 0.050, Pco(2) 44.4 ± 2.2 and 34.2 ± 2.1, and bicarbonate 17.8 ± 1.02 and 14.6 ± 1.4 for rapid and slow correction, respectively. Under the conditions of this experiment, rapid correction of acidemia did not provoke paradoxical CSF acidosis.

Response and sensitivity of lipid related molecular structure to wet and dry heating in canola tissue.

Heat treatments are used to manipulate nutrient utilization, availability and functional properties. The objective of this study was to characterize any molecular level changes of the functional groups associated with lipid structure in canola (Brassica) seed, as affected during the wet and dry heat treatment processes using molecular spectroscopy. The parameters included lipid CH(3) asymmetric (ca. 2970-2946 cm(-1)), CH(2) asymmetric (ca. 2945-2880 cm(-1)), CH(3) symmetric (ca. 2881-2864 cm(-1)) and CH(2) symmetric (ca. 2864-2770 cm(-1)) functional groups, lipid carbonyl CO ester group (ca. 1774-1711 cm(-1)), lipid unsaturation group (CH attached to C-C) (ca. 3007 cm(-1)) as well as their ratios. Hierarchical cluster analysis (CLA) and principal components analysis (PCA) were conducted to identify molecular spectral differences. Raw canola seeds were used for the control or autoclaved at 120°C for 1h (HT-1: wet heating) or dry roasted at 120°C for 1h (HT-2: dry heating). Molecular spectral analysis of lipid functional group ratios were not significantly changed (P>0.05) in the CH(2) asymmetric to CH(3) asymmetric stretching band peak intensity ratios for canola seed. Both wet (HT-1) and dry heating method (HT-2) had no significant effect (P>0.05) on lipid carbonyl CO ester group and lipid unsaturation group (CH attached to CC). Multivariate molecular spectral analyses, CLA and PCA, were unable to make distinctions between the different treatment original spectra at the CH(3) and CH(2) asymmetric and symmetric region (ca. 2992-2770 cm(-1)), unsaturated lipids band region (ca. 3025-2993 cm(-1)) and lipid carbonyl CO ester band region (ca. 1774-1711 cm(-1)). The results indicated that both dry and wet heating of given intense had no impact to the molecular spectrum in lipid related functional groups of canola seed, and was not strong enough to elicit heat-induced changes in lipid conformation.

Evidence-based risk assessment and recommendations for physical activity: arthritis, osteoporosis, and low back pain.

We systematically reviewed the safety of physical activity (PA) for people with arthritis, osteoporosis, and low back pain. We searched PubMed, MEDLINE, Sport Discus, and the Cochrane Central Register of Controlled Trials (1966 through March 2008) for relevant articles on PA and adverse events. A total of 111 articles met our inclusion criteria. The incidence for adverse events during PA was 3.4%-11% (0.06%-2.4% serious adverse events) and included increased joint pain, fracture, and back pain for those with arthritis, osteoporosis, and low back pain, respectively. Recommendations were based on the Appraisal of Guidelines for Research and Evaluation, which applies Levels of Evidence based on type of study ranging from high-quality randomized controlled trials (Level 1) to anecdotal evidence (Level 4) and Grades from A (strong) to C (weak). Our main recommendations are that (i) arthritic patients with highly progressed forms of disease should avoid heavy load-bearing activities, but should participate in non-weight-bearing activities (Level 2, Grade A); and (ii) patients with osteoporosis should avoid trunk flexion (Level 2, Grade A) and powerful twisting of the trunk (Level 3, Grade C); (iii) patients with acute low back pain can safely do preference-based PA (i.e., PA that does not induce pain), including low back extension and flexion (Level 2, Grade B); (iv) arthritic patients with stable disease without progressive joint damage and patients with stable osteoporosis or low back pain can safely perform a variety of progressive aerobic or resistance-training PAs (Level 2, Grades A and B). Overall, the adverse event incidence from reviewed studies was low. PA can safely be done by most individuals with musculoskeletal conditions.

Short-term heavy resistance training eliminates age-related deficits in muscle mass and strength in healthy older males.

The objective of this investigation was to determine whether short-term heavy resistance training (RT) in healthy older men could eliminate deficits in muscle mass and strength (ST) compared with healthy younger men. Seventeen older men (60-71 yr) performed supervised RT for 22 weeks. Before and after RT, measurements were made for lean tissue mass (LTM), muscle thickness (MT), and ST (leg and bench press 1 repetition maximum) and were compared with values of younger men (n = 22-60 for the different measures, 18-31 yr). Before training, older men had significantly lower (p < 0.05) LTM (58.4 ± 7.0 kg), MT (3.4 ± 0.7 cm), and ST (leg press = 168 ± 33 kg; bench press = 75 ± 18 kg) compared with younger men (LTM 64.3 ± 7.1 kg; MT 4.0 ± 0.8 cm; leg press = 231 ± 54 kg; bench press = 121 ± 31 kg). All deficits were eliminated after 22 weeks of RT (LTM = 60.5 ± 7.6 kg; MT = 4.0 ± 0.7 cm; leg press = 222 ± 48 kg; bench press = 107 ± 19 kg). Short-term, heavy RT in healthy older men is sufficient to overcome deficits in muscle mass and ST when compared with healthy younger men. The practical application from this research is that healthy older men can be prescribed a whole-body heavy RT program to substantially increase muscle mass and ST to levels similar to young, active individuals.

Conjugated linoleic acid combined with creatine monohydrate and whey protein supplementation during strength training.

PURPOSE: The authors examined the combined effects of conjugated linoleic acid (CLA), creatine (C), and whey protein (P) supplementation during strength training. METHODS: Sixty-nine participants (52 men, 17 women; M +/- SD age 22.5 +/-2.5 yr) were randomly assigned (double-blind) to 1 of 3 groups: CCP (6 g/d CLA + 9 g/d C + 36 g/d P; n = 22), CP (C + P + placebo oil; n = 25), or P (P + placebo oil; n = 22) during 5 wk of strength training (4-5 sets, 6-12 repetitions, 6 d/wk). Measurements were taken for body composition (air-displacement plethysmography), muscle thickness (ultrasound) of the flexors and extensors of the elbow and knee, 1-repetition-maximum (1-RM) strength (leg press and bench press), urinary markers of bone resorption (N-telopeptides, NTx), myofibrillar protein catabolism (3-methylhistidine; 3-MH), oxidative stress (8-isoprostanes), and kidney function (microalbumin) before and after training. RESULTS: Contrast analyses indicated that the CCP group had a greater increase in bench-press (16.2% +/- 11.3% vs. 9.7% +/- 17.0%; p < .05) and leg-press (13.1% +/- 9.9% vs. 7.7% +/-14.2%; p < .05) strength and lean-tissue mass (2.4% +/- 2.8% vs. 1.3% +/-4.1%; p < .05) than the other groups combined. All groups increased muscle thickness over time (p < .05). The relative change in 3-MH (CCP -4.7% +/- 70.2%, CP -0.4% +/- 81.4%, P 20.3% +/- 75.2%) was less in the groups receiving creatine (p < .05), with the difference for NTx also close to significance (p = .055; CCP -3.4% +/- 66.6%, CP -3.9% +/- 64.9%, P 26.0% +/- 63.8%). There were no changes in oxidative stress or kidney function. CONCLUSION: Combining C, CLA, and P was beneficial for increasing strength and lean-tissue mass during heavy resistance training.

Low-dose creatine combined with protein during resistance training in older men.

PURPOSE: To determine whether low-dose creatine and protein supplementation during resistance training (RT; 3 d x wk(-1); 10 wk) in older men (59-77 yr) is effective for improving strength and muscle mass without producing potentially cytotoxic metabolites (formaldehyde). METHODS: Older men were randomized (double-blind) to receive 0.1 g x kg(-1) creatine + 0.3 g x kg(-1) protein (CP; n = 10), creatine (C; n = 13), or placebo (PLA; n = 12) on training days. Measurements before and after RT included lean tissue mass (air-displacement plethysmography), muscle thickness (ultrasound) of elbow, knee, and ankle flexors and extensors, leg and bench press strength, and urinary indicators of cytotoxicity (formaldehyde), myofibrillar protein degradation [3-methylhistidine (3-MH)],and bone resorption [cross-linked N-telopeptides of type I collagen (NTx)]. RESULTS: Subjects in C and CP groups combined experienced greater increases in body mass and total muscle thickness than PLA (P < 0.05). Subjects who received CP increased lean tissue mass (+5.6%) more than C (+2.2%) or PLA (+1.0%; P < 0.05) and increased bench press strength (+25%) to a greater extent than C and PLA combined (+12.5%; P < 0.05). CP and C did not differ from PLA for changes in formaldehyde production (+24% each). Subjects receiving creatine (C and CP) experienced a decrease in 3-MH by 40% compared with an increase of 29% for PLA (P < 0.05) and a reduction in NTx (-27%) versus PLA (+13%; P = 0.05). CONCLUSIONS: Low-dose creatine combined with protein supplementation increases lean tissue mass and results in a greater relative increase in bench press but not leg press strength. Low-dose creatine reduces muscle protein degradation and bone resorption without increasing formaldehyde production.

D-Lactic acid-induced neurotoxicity in a calf model.

Lactic acidosis (DAC) occurs as a complication of short-bowel syndrome in humans and in a variety of other gastrointestinal disorders in monogastrics and ruminants. DAC is associated with signs of impaired central nervous system (CNS) function including ataxia and coma. The objective of this experiment was to determine whether either acidification of nervous tissue or d-lactic acid is responsible for decreased neurological function. Eight Holstein calves (32 +/- 11 days, 70 +/- 10 kg) were surgically catheterized with indwelling intravenous jugular and atlanto-occipital space cerebrospinal fluid (CSF) catheters and infused for 6 h in random order with isomolar dl-lactic acid (dl-LA), l-lactic acid (l-LA), hydrochloric acid (HCl), or saline. dl-LA induced ataxia after 4 h of infusion and produced the greatest obtunding of CNS function (at 7 h, score 8.0 +/- 0.4), whereas the other infusions caused neither ataxia nor scores over 1.5 (P < 0.01 from dl-LA). dl-LA induced significantly less acidemia than HCl (at 6 h pH 7.13 +/- 0.06 and 7.00 +/- 0.04, base excess -16 +/- 1 and -23 +/- 3 mmol/l, bicarbonate 11 +/- 1 and 8 +/- 1 mmol/l respectively, all P < 0.01) but greater than l-LA and saline (P < 0.01). CSF changes followed a similar but less pronounced pattern. Although HCl infusion produced a severe acidemia and CSF acidosis, only minor effects on neurological function were evident suggesting that d-lactate has a direct neurotoxic effect that is independent of acidosis. Conversely, l-LA produced only minor neurological changes.

Protein supplementation before and after resistance training in older men.

We determined the effects of protein supplementation immediately before (PRO-B) and after (PRO-A) resistance training (RT; 12 weeks) in older men (59-76 years), and whether this reduces deficits in muscle mass and strength compared to younger men (18-40 years). Older men were randomized to PRO-B (0.3 g/kg protein before RT + placebo after RT, n=9), PRO-A (placebo before + protein after RT, n=10), or PLA (placebo before and after RT, n=10). Lean tissue mass, muscle thickness of the elbow, knee, and ankle flexors and extensors, and leg and bench press strength were measured before and after RT and compared to databases of younger subjects (n=22-60). Myofibrillar protein degradation (3-methylhistidine) and bone resorption (cross-linked N-telopeptides) were also measured before and after RT. Lean tissue mass, muscle thickness (except ankle dorsi flexors), and strength increased with training (P<0.05), with little difference between groups. There were no changes in 3-methylhistidine or cross-linked N-telopeptides. Before RT, all measures were lower in the older compared to younger groups (P<0.05), except for elbow extensor muscle thickness. Following training, muscle thickness of the elbow flexors and ankle dorsi flexors and leg press strength were no longer different than the young, and elbow extensor muscle thickness was greater in the old men (P<0.05). Supplementation with protein before or after training has no effect on muscle mass and strength in older men. RT was sufficient to overcome deficits in muscle size of the elbow flexors and ankle dorsi flexors and leg press strength in older compared to younger men.