John R. Ingram

High and low rigor temperature effects on sheep meat tenderness and ageing

Immediately after electrical stimulation, the paired m. longissimus thoracis et lumborum (LT) of 40 sheep were boned out and wrapped tightly with a polyethylene cling film. One of the paired LTs was chilled in 15°C air to reach a rigor mortis (rigor) temperature of 18°C and the other side was placed in a water bath at 35°C and achieved rigor at this temperature. Wrapping reduced rigor shortening and mimicked meat left on the carcass. After rigor, the meat was aged at 15°C for 0, 8, 26 and 72 h and then frozen. The frozen meat was cooked to 75°C in an 85°C water bath and shear force values obtained from a 1×1 cm cross-section. The shear force values of meat for 18 and 35°C rigor were similar at zero ageing, but as ageing progressed, the 18 rigor meat aged faster and became more tender than meat that went into rigor at 35°C (P<0.001). The mean sarcomere length values of meat samples for 18 and 35°C rigor at each ageing time were significantly different (P<0.001), the samples at 35°C being shorter. When the short sarcomere length values and corresponding shear force values were removed for further data analysis, the shear force values for the 35°C rigor were still significantly greater. Thus the toughness of 35°C meat was not a consequence of muscle shortening and appears to be due to both a faster rate of tenderisation and the meat tenderising to a greater extent at the lower temperature. The cook loss at 35°C rigor (30.5%) was greater than that at 18°C rigor (28.4%) (P<0.01) and the colour Hunter L values were higher at 35°C (P<0.01) compared with 18°C, but there were no significant differences in a or b values.

Impact of climate on thermal rhythm in pastoral sheep.

The effects of environmental conditions on temperature rhythms were investigated in ewe lambs at pasture. Two groups of 20 lambs had heart rate (HR), vaginal temperature (T(v)), ear-canal temperature (T(c)) and ear-pinna temperature (T(p)) monitored continuously for 3 days. Climatic conditions were recorded at the same time and Temperature Humidity Index (THI) calculated. One group experienced fine clear weather for the 3 days, the other group experienced 2 days of heavy rain. During periods of fine weather, the daily rhythm for T(v) and T(c) was monophasic. However, heavy rain and a constant THI reduced the amplitude of the recorded temperature rhythms. Daily T(v) and T(c) patterns correlated strongly with THI, with a phase lag of 2 h. Peak T(v) and T(c) were at approximately 17:00 h each day. Mean maximum daily amplitudes were approximately 1.3 degrees C for T(v) and T(c). Mean T(v) was 39.3+/-0.1 and 39.6+/-0.1 for weeks 1 and 2, respectively, while mean T(c) was 38.9+/-0.1 and 39.2+/-0.1. Changes in T(v) and T(c) were closely correlated. We conclude that climate has a major effect on body temperature rhythms.

Acute salivary hormone responses to complex exercise bouts.

Beaven, CM, Gill, ND, Ingram, JR, and Hopkins, WG. Acute salivary hormone responses to complex exercise bouts. J Strength Cond Res 25(4): 1072-1078, 2011-The combination of resistance and plyometric training, or complex training, may yield greater functional gains than either method alone. As steroid hormones respond to exercise stimuli and modulate the functional outcomes, it is possible that complex training creates an enhanced anabolic physiological milieu for adaptation. We investigated acute responses of salivary testosterone and cortisol to complex exercise bouts. After a standardized warm-up, 16 semiprofessional rugby players performed 1 of 4 exercise bouts in a cross-over manner: power-power; power-strength; strength-power; or strength-strength. Each player completed each of the 4 bouts twice over a 4-week period in a balanced random order such that each player performed a total of 8 bouts. The power block consisted of 3 sets of 3 repetitions of jump squat exercise at 50% of 1-repetition maximum load. The strength block consisted of three sets of three repetitions of box squat exercise at a 3-repetition maximum load. There were 3-minute rest periods between sets and 4-minute rest periods between exercise blocks. Saliva was sampled before, during, and immediately after the exercise bout. The greatest overall hormonal responses were a small increase in testosterone (13%; 90% confidence limits ±7%) and a trivial increase in cortisol (27%; ±30%) after the strength-power bout. A clear difference was observed between the strength-power and the power-power bouts immediately after exercise for testosterone (10%; ±8%) and cortisol (29%; ±17%). The preceding exercise block had little effect on subsequent strength and power performance. The hormonal response after the strength-power bout suggests that this exercise sequence provides an enhanced anabolic milieu for adaptation.

Rapid Saliva Processing Techniques for Near Real-Time Analysis of Salivary Steroids and Protein

Introduction: Point‐of‐care (POC) measurements using saliva samples have immense potential to assess systemic health and wellbeing, but sample viscosity and contaminants can affect analyses. We sought a portable clean‐up method for whole saliva appropriate for use with POC measurement techniques such as biosensors.

A modified method using the SonoPrep® ultrasonic skin permeation system for sampling human interstitial fluid is compatible with proteomic techniques

The use of biomarkers in skin is a novel diagnostic tool. Interstitial fluid (ISF) from skin provides a snapshot of proteins secreted at the time of sampling giving insights into the patients health status.

Development and validation of a sensitive immunoassay for the skeletal muscle isoform of creatine kinase.

Creatine kinase (CK) is a marker of muscle damage and pathology present as multiple tissue-specific circulating isoforms. CK is often measured using enzyme activity assays that are unable to distinguish these isoforms. We have developed an immunoassay specific for the MM isoform of CK, found predominantly in skeletal muscle, which uses very small volumes of plasma (1-2 microL). A sandwich enzyme-linked immunosorbent assay (ELISA) for CK-MM was developed using isoform-specific antibodies. Cross-reactivity with CK-BB and MB isoforms was also assessed. The ELISA was validated using plasma samples from a group of athletes, and the measured CK-MM concentrations were correlated with CK enzyme activity assays measured by a contractor using the same samples. The CK-MM ELISA has a limit of detection of 0.02 ng/mL, an IC(50) of 2.3 ng/mL, and 5.8% cross-reactivity with CK-MB. CK-MM concentrations measured using this assay correlate well (p<0.0001, Spearman r=0.89) with enzyme activity assays. The CK-MM-specific ELISA can be used to help assess skeletal muscle damage independent of enzyme activity or interference from other CK isoforms, leading to more precise studies of muscle biology.

Physical Interactions and Expression Quantitative Traits Loci Identify Regulatory Connections for Obesity and Type 2 Diabetes Associated SNPs

The mechanisms that underlie the association between obesity and type 2 diabetes are not fully understood. Here, we investigated the role of the 3D genome organization in the pathogeneses of obesity and type-2 diabetes. We interpreted the combined and differential impacts of 196 diabetes and 390 obesity associated single nucleotide polymorphisms (SNPs) by integrating data on the genes with which they physically interact (as captured by Hi-C) and the functional [i.e., expression quantitative trait loci (eQTL)] outcomes associated with these interactions. We identified 861 spatially regulated genes (e.g., AP3S2, ELP5, SVIP, IRS1, FADS2, WFS1, RBM6, HORMAD1, PYROXD2), which are enriched in tissues (e.g., adipose, skeletal muscle, pancreas) and biological processes and canonical pathways (e.g., lipid metabolism, leptin, and glucose-insulin signaling pathways) that are important for the pathogenesis of type 2 diabetes and obesity. Our discovery-based approach also identifies enrichment for eQTL SNP-gene interactions in tissues that are not classically associated with diabetes or obesity. We propose that the combinatorial action of active obesity and diabetes spatial eQTL SNPs on their gene pairs within different tissues reduces the ability of these tissues to contribute to the maintenance of a healthy energy metabolism.

Duodenal and ileal glucose infusions differentially alter gastrointestinal peptides, appetite response, and food intake: a tube feeding study

Background: Activation of the ileal brake through the delivery of nutrients into the distal small intestine to promote satiety and suppress food intake provides a new target for weight loss. Evidence is limited, with support from naso-ileal lipid infusion studies.Objective: The objective of the study was to investigate whether glucose infused into the duodenum and ileum differentially alters appetite response, food intake, and secretion of satiety-related gastrointestinal peptides.Design: Fourteen healthy male participants were randomly assigned to a blinded 4-treatment crossover, with each treatment of single-day duration. On the day before the intervention (day 0), a 380-cm multilumen tube (1.75-mm diameter) with independent port access to the duodenum and ileum was inserted, and position was confirmed by X-ray. Subsequently (days 1-4), a standardized breakfast meal was followed midmorning by a 90-min infusion of isotonic glucose (15 g, 235 kJ) or saline to the duodenum or ileum. Appetite ratings were assessed with the use of visual analog scales (VASs), blood samples collected, and ad libitum energy intake (EI) measured at lunch, afternoon snack, and dinner.Results: Thirteen participants completed the 4 infusion days. There was a significant effect of nutrient infused and site (treatment × time, P < 0.05) such that glucose-to-ileum altered VAS-rated fullness, satisfaction, and thoughts of food compared with saline-to-ileum (Tukeys post hoc, P < 0.05); decreased ad libitum EI at lunch compared with glucose-to-duodenum [-22%, -988 ± 379 kJ (mean ± SEM), Tukeys post hoc, P < 0.05]; and increased glucagon-like peptide-1 (GLP-1) and peptide YY (PYY) compared with all other treatments (Tukeys post hoc, P < 0.05).Conclusions: Macronutrient delivery to the proximal and distal small intestine elicits different outcomes. Glucose infusion to the ileum increased GLP-1 and PYY secretion, suppressed aspects of VAS-rated appetite, and decreased ad libitum EI at a subsequent meal. Although glucose to the duodenum also suppressed appetite ratings, eating behavior was not altered. This trial was registered at www.anzctr.org.au as ACTRN12612000429853.

A proprietary plant-based, functional ingredient, Amarasate™ extract, suppresses food intake and stimulates gastrointestinal peptide hormones in healthy men.

Track 2: From cells to integrative biology Session 9: Brain circuits and energy balance T2:S9:01 Diet-induced neuroplasticity in fronto-cortical and mesolimbic circuits Borgland, S.* University of Calgary In an environment rich in easily accessible palatable foods, the ability to withhold food consumption is of key importance for maintaining a healthy body weight. We know the brain’s ‘reward system’ responds to the sight, smell and taste of food and can override the homeostatic system, which matches food intake with energy balance. Indeed, dopamine (DA) from the ventral tegmental area (VTA) promotes ingestive behaviors by increasing motivation or saliency of food cues. Further, the orbitofrontal cortex (OFC) receives input from DA neurons and is important for monitoring the current value of rewards and thus plays a critical role in satiety to food of the same sensory properties. Here, we show data demonstrating that synapses in the VTA or OFC are modified by diet experience. In addition, diet or obesity can alter food approach behaviours as well as reward devaluation. Taken together, these studies demonstrate how the type of food or obesity itself can rewire circuits in the brain important for non-homeostatic food seeking. T2:S9:02 Treat obesity using inflammation-resistant hypothalamic stem cells Cai, D. and Rice, M.* Albert Einstein College of Medicine Hypothalamic microinflammation has been shown to participate in the chronic development and progression of obesity and related metabolic syndrome, and is known to increase with age after young adulthood. Contributing factors of hypothalamic microinflammation include system (e.g., chronic overnutrition, aging), subcellular (e.g., ER stress, autophagic defect, RNA stress granules), and molecular (e.g., IKKβ/NF-ĸB activation) components, with this microinflammatory process occurring in and being mediated by both neurons and glia. Microinflammation also impacts the functioning of hypothalamic neural stem cells (htNSCs). Only recently have htNSCs been identified in the adult mouse hypothalamus, and their relevance in physiology and disease still remain unclear. Research from our laboratory revealed that adult htNSCs are multipotent and mostly reside within the mediobasal hypothalamus, but are vulnerable under inflammatory hypothalamic microenvironment, resulting in depletion and impaired hypothalamic neurogenesis and thus potentially a neurodegenerative mechanism of metabolic syndromeand aging-associated diseases. More recently, our laboratory research has further addressed the disease relevance of htNSCs, showing that loss of htNSCs can cause perturbations in metabolic homeostasis, including the development of eating disorder and glucose intolerance. To counter this, our