A revised model of energy transactions and body composition in sheep.

A mechanistic, dynamic model was developed to calculate body composition in growing lambs by calculating heat production (HP) internally from energy transactions within the body. The model has a fat pool (f) and three protein pools: visceral (v), nonvisceral (m), and wool (w). Heat production is calculated as the sum of fasting heat production, heat of product formation (HrE), and heat associated with feeding (HAF). Fasting heat production is represented as a function of visceral and nonvisceral protein mass. Heat associated with feeding (HAF) is calculated as ((1 - km) x MEI), where km is partial efficiency of ME use for maintenance, and MEI = metabolizable energy intake) applies at all levels above and below maintenance. The value of km derived from data where lambs were fed above maintenance was 0.7. Protein change (dp/dt) is the sum of change in the m, v, and w pools, and change in fat is equal to net energy available for gain minus dp/dt. Heat associated with a change in body composition (HrE) is calculated from the change in protein and fat with estimated partial efficiencies of energy use of 0.4 and 0.7 for protein and fat, respectively. The model allows for individuals to gain protein while losing fat or vice versa. When evaluated with independent data, the model performed better than the current Australian feeding standards (Freer et al., 2007) for predicting protein gain in the empty body but did not perform as well as for gain of fat and fleece-free empty body weight. Models performed similarly for predicting clean wool growth. By explicit representation of the major energy using processes in the body, and through simplification of the way body composition is computed in growing animals, the model is more transparent than current feeding systems while achieving similar performance. An advantage of this approach is that the model has the potential for wider applicability across different growth trajectories and can explicitly account for the effects of systematic changes on energy transactions, such as the effects of selective breeding, growth manipulation, or environmental changes.

Based on prior work by Oltjen et al. (2006), a revised dynamic, mechanistic model was developed to improve the prediction of the composition of protein and fat in the body of growing ruminants. The revised model calculates heat production (HP) internally as a function of fasting HP, heat associated with feeding, and HP from changes in fat and protein within the body. Heat associated with product formation is calculated from changes in body protein and fat, with separate efficiencies for each, while heat associated with feeding is a constant proportion of metabolizable energy intake and applies at all levels of feeding above and below maintenance. When evaluated against novel data, the revised model performed similarly to current Australian feeding standards (Freer et al., 2007) Unlike the Freer model, the revised model captures variation in HP arising from feed as well as gain of protein and fat. The revised model explicitly represents protein in the body as two pools with markedly different rates of energy expenditure, improving representation of the underlying biology compared to current feeding systems. This provides a more flexible way to predict energy requirements and body composition in growing animals while achieving similar performance to current feeding systems.

Internal endpoint temperature (level of cooking doneness) effects on the fatty acid and mineral profiles of grilled lamb m. longissimus lumborum.

This study compared the fatty acid and mineral concentrations of lamb meat that was prepared to different levels of cooking doneness. Ten m. longissimus lumborum were each sectioned into 4 slices that were randomly assigned to be uncooked or grilled to an internal end-point temperature of 60 °C (rare), 71 °C (medium), or 77 °C (well done). It was found that cooking loss increased as the level of cooking doneness increased. The proportion of most major fatty acids were not altered by cooking. However, when adjusted for cooking loss (i.e., mg/135 g serve of lamb as-is equivalent prepared to each level of cooking doneness), the concentration of most major fatty acids, including C16:0, C18:0, C18:1n-9, and many conjugated linoleic acids, were lowered after grilling to any level of cooking doneness and compared to the uncooked samples. The omega-6 to omega-3 ratio was lowest for the uncooked samples and highest for those prepared to a well done level of cooking doneness. Conversely, the concentration of health claimable omega-3 fatty acids in the uncooked meat was retained upon cooking and across all the different internal endpoint temperatures. Calcium, magnesium, phosphorous, potassium, and sodium were reduced with preparation of lamb meat to any level of cooking doneness, compared with uncooked meat. Zinc, iron, and selenium were retained within the cooked samples. These findings show that consumer preference for a level of cooking doneness will have only minor effects on the concentration of minerals and fatty acids in lamb meat.

The effect of perennial and annual wheat forages, fed with or without lucerne, on the fatty acid profile and oxidative status of lamb meat.

The current study investigated the fatty acid profile and oxidative status of the meat from lambs that were fed a novel perennial wheat or a conventional annual wheat, either as a cereal monoculture or lucerne biculture. Twelve lambs were assigned to each of the four dietary treatments (48 lambs in total) and held within individual pens for the duration of the 28 day feeding study. Lambs were slaughtered and the longissimus lumborum (LL) and semimembranosus (SM) muscles analysed. The independent effect of wheat type on fatty acid concentrations was negligible. The concentration of long-chain saturated and omega-6 polyunsaturated fatty acids was higher when lucerne was included in the diet. Only monounsaturated fatty acids were affected by the interaction between wheat type and lucerne. The three-way interaction between wheat type, lucerne and muscle was only significant for the concentration of C12:0 and anteiso-C15:0. The concentration of thiobarbituric reactive substances and vitamin E was higher in meat from lambs fed a lucerne biculture, compared with those fed a cereal monoculture. Furthermore, and independent to dietary treatment, higher concentration of omega-3, omega-6 and other health claimable fatty acids were found in the SM, compared with the LL. This information will support industry adoption of novel perennial wheat polycultures and help producers to utilise it as a dual-purpose crop for the production of grain and/or sheep meat.

The influence of peri-conception and first trimester dietary restriction of protein in cattle on meat quality traits of entire male progeny.

Primiparous Santa Gertrudis heifers were used to evaluate the effects of gestational dietary protein content on meat quality traits of 20month old bull progeny (n=40). At -60d before AI, heifers were randomly allocated to HIGH or LOW protein diet (HPERI and LPERI). From 24dpc, half of each treatment group changed to an alternative post-conception HIGH or LOW protein diet (HPOST and LPOST). LPERI and LPOST diets resulted in higher shear force of the semitendinosus muscle than HPERI (P=0.053) and HPOST (P=0.003), respectively. Heat-soluble collagen in the semitendinosus muscle was lower (P=0.019) for LPERI than HPERI. Collagen and tenderness of the longissimus muscle were not affected by dam nutrition (P>0.05). Color, pH, sarcomere length, cooking loss, compression values, desmin and troponin-T degradation, fiber type, intramuscular fat and polyunsaturated fatty acid content were not affected by dam nutrition during the peri-conception and first trimester gestational period (P>0.05).

Differential response to an algae supplement high in DHA mediated by maternal periconceptional diet: intergenerational effects of n-6 fatty acids.

Algae high in docosahexaenoic acid (DHA) may provide a source of long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) for inclusion in the diet of lambs to improve the LCn-3PUFA status of meat. The effect of background LCn-3PUFA status on the metabolism of high DHA algae is, however, unknown. The aim of the current study was to determine whether the response to a high in DHA algae supplement fed to lambs for six weeks prior to slaughter was mediated by a maternal periconceptional diet. Forty Poll Dorset × Border Leicester × Merino weaner lambs were allocated to receive either a ration based on oat grain, lupin grain, and chopped lucerne (control) or the control ration with DHA-Gold™ algae included at 1.92 % DM (Algae) based on whether the dams of lambs had previously been fed a diet high in n-3 or n-6 around conception. LCn-3PUFA concentration was determined in plasma and red blood cells (RBC) prior to and following feeding. The concentrations of EPA and DHA in the plasma and RBC of lambs receiving the control ration were significantly (p < 0.001) lower when lambs received the ration for 14 days compared with pre-feeding concentrations. The concentrations of EPA and DHA were also significantly (p < 0.001) higher when lambs consumed the Algae ration compared with the control ration for 42 days. The increase in EPA and DHA was, however, significantly (p < 0.05) lower if lamb dams had previously been fed a diet high in n-6 at conception. Assessing the previous nutrition and n-3 status of lambs may allow producers to more accurately predict the likely response to supplements high in LCn-3PUFA, particularly, DHA.

Increased prostaglandin response to oxytocin in ewes fed a diet high in omega-6 polyunsaturated fatty acids.

Diets high in omega-6 polyunsaturated fatty acids (n-6) are associated with increased prostaglandin F(2α) (PGF(2α)) synthesis in cattle, however, the specific effects on the potential prostaglandin response to an oxytocin challenge in sheep have not been reported. The aim of the current study was to determine whether oxytocin-stimulated PGF(2α) was significantly increased when ewes were fed a diet high in n-6 compared with a control diet low in n-6. Merino x Border Leicester ewes (n = 30) received one of two dietary treatments, either high in n-6 (70 % oat grain) or low in n-6 (control diet, 100 % cereal/legume silage). Ewes consumed the diets for 44 days prior to two consecutive oxytocin challenges. Plasma n-6 and PGF(2α) metabolite (PGFM) concentrations following oxytocin challenge were greater (P < 0.05) when ewes were fed a diet high in n-6 compared with the control diet. A higher availability of n-6 may have lead to an increased in vivo synthesis of PGF(2α), however, further research is required to determine the exact mechanisms involved.

Improved extraction of saturated fatty acids but not omega-3 fatty acids from sheep red blood cells using a one-step extraction procedure.

Several methods are available to extract total lipid and methylate fatty acids from a range of samples including red blood cells (RBC). Fatty acid analysis of human RBC can be undertaken using a two-step extraction and methylation or a combined one-step extraction and methylation procedure. The lipid composition of sheep RBC differs significantly from that of humans and may affect their extraction. The purpose of the current study was to examine the efficiency of extraction of lipid and detection of fatty acids from sheep RBC using a one-step procedure. Fatty acids were analysed using a one-step extraction and methylation procedure using methanol:toluene and acetyl chloride in comparison with a two-step procedure involving extraction of lipid using chloroform:methanol and separate methylation. Concentrations of saturated fatty acids including C16:0 and C18:0 were significantly higher (42.6 and 33.9 % respectively) following extraction using the one-step procedure compared with the two-step procedure. However, concentrations of some polyunsaturated fatty acids, including C20:5n-3 and C22:6n-3 were not significantly different between either procedure. The improved detection of fatty acids may be related to the ability of different solvents to extract different lipid fractions. The differential extraction of lipids and detection of fatty acids from sheep RBC may have important implications in studies examining the effect of dietary treatment on the possible health benefits of fatty acids.

Wounding words: swearing and verbal aggression in an inpatient setting.

PURPOSE: The aim of the research was to investigate swearing and verbal aggression in Australian inpatient settings, including incidence, gender, patient motivation, and nursing interventions. DESIGN AND METHODS: A mixed methods approach utilizing the Overt Aggression Scale and a survey of 107 nurses' perceptions of their experience of swearing was used. FINDINGS: High levels of swearing and verbal aggression were found, with differing patterns for male and female patients. Nurses subjected to swearing experienced high levels of distress, especially females. All nurses appeared to use a limited range of interventions to deal with patient aggression. PRACTICAL IMPLICATIONS: In order to provide optimal care for patients, there is a clear need to improve nurses' ability to predict and prevent aggression.

Estimated intakes of meat and fish by children and adolescents in Australia and comparison with recommendations.

Long-chain n-3 PUFA are considered important for cardiovascular health and brain development. Meat other than fish contributes significantly to total intakes of long-chain n-3 PUFA in adults; however, there are limited published data examining the intake of individual meat sources in children and adolescents in the Australian population. A review of literature was conducted using PubMed, Agricola and CAB Abstracts using the terms 'intake', 'beef', 'lamb', 'pork', 'poultry', 'fish', 'children' and 'adolescents' and using reference lists in published articles. Studies and surveys were identified that contained published values for intakes of meat or fish. Two national dietary surveys of children and adolescents were conducted in Australia in 1985 and 1995 and two regional surveys were conducted in Western Sydney and Western Australia in 1994 and 2003, respectively. Comprehensive data for the intake of individual meat sources were not reported from the 1995 survey, but estimations of intake were calculated from published values. Reported intakes of meat and fish are generally lower in females than males and tend to increase with age. Weighted mean intakes of red meat (beef plus lamb) across the three most recent studies were 67.3 and 52.2 g/d, respectively, for males and females aged between 7 and 12 years and 87.7 and 54.2 g/d, respectively, for males and females aged 12-18 years. These weighted intakes are within Australian guidelines and are likely to contribute significantly to total long-chain n-3 PUFA intake in children and adolescents in the Australian population.

Long-chain omega-3 polyunsaturated fatty acids in the blood of children and adolescents with juvenile bipolar disorder.

Reduced long-chain omega-3 polyunsaturated fatty acids (LCn-3PUFA), including eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), have been reported in adult patients suffering from depression and bipolar disorder (BD). LCn-3PUFA status has not previously been examined in children and adolescents with BD compared with healthy controls. Fifteen children and adolescents (9-18 years, M +/- SD = 14.4 +/- 3.48) diagnosed with juvenile bipolar disorder (JBD) and fifteen healthy age and sex-matched controls were assessed for dietary intake and fasting red blood cell (RBC) membrane concentrations of LCn-3PUFA. Fatty acid concentrations were compared between participants diagnosed with JBD and controls after controlling for dietary intake. RBC membrane concentrations of EPA and DHA were not significantly lower in participants diagnosed with JBD compared with healthy controls (M +/- sem EPA = 3.37 +/- 0.26 vs. 3.69 +/- 0.27 microg/mL, P = 0.458; M +/- sem DHA = 22.08 +/- 2.23 vs. 24.61 +/- 2.38 microg/mL, P = 0.528) after controlling for intake. Red blood cell DHA was negatively (r = -0.55; P = 0.044) related to clinician ratings of depression. Although lower RBC concentrations of LCn-3PUFA were explained by lower intakes in the current study, previous evidence has linked reduced LCn-3PUFA to the aetiology of BD. As RBC DHA was also negatively related to symptoms of depression, a randomised placebo-controlled study examining supplementation with LCn-3PUFA as an adjunct to standard pharmacotherapy appears warranted in this patient population.

Macadamia nut consumption modulates favourably risk factors for coronary artery disease in hypercholesterolemic subjects.

Macadamia nuts are rich source of monounsaturated fats (oleic and palmitoleic acids) and contain polyphenol compounds, therefore, their consumption can be expected to impart health benefits to humans. This study was conducted to examine the effects of consuming macadamia nuts in hypercholesterolemic male individuals on plasma biomarkers of oxidative stress, coagulation and inflammation. Seventeen hypercholesterolemic male subjects were given macadamia nuts (40-90 g/day), equivalent to 15% energy intake, for a period of 4 weeks. As expected, monounsaturated fatty acids (16:1n-7, 18:1n-9 and 20:1n-9) were elevated in the plasma lipids of all volunteers following intervention with macadamia nuts. Plasma markers of inflammation (leukotriene, LTB(4)) and oxidative stress (8-isoprostane) were significantly lower (1,353 +/- 225 vs. 1,030 +/- 129 pg/mL and 876 +/- 97 vs. 679 +/- 116 pg/mL, respectively) within 4 weeks following macadamia nut intervention. There was a non-significant (23.6%) reduction in the plasma TXB(2)/PGI(2) ratio following macadamia nut consumption. This study demonstrates, for the first time, that short-term macadamia nut consumption modifies favourably the biomarkers of oxidative stress, thrombosis and inflammation, the risk factors for coronary artery disease, despite an increase in dietary fat intake. These data, combined with our previous results on cholesterol-lowering effects of macadamia nuts, suggest that regular consumption of macadamia nuts may play a role in the prevention of coronary artery disease.

Long chain omega-3 polyunsaturated fatty acids in the treatment of psychiatric illnesses in children and adolescents.

OBJECTIVE: Long chain omega-3 polyunsaturated fatty acids (LCn-3PUFA) are in increasing use in the general population to treat health problems. The objective of the current article is to review the evidence for the rationale and benefit of LCn-3PUFA in the treatment of common psychiatric disorders in children and adolescents. METHODS: A search of Psychlit, PubMed and Cochrane Databases was conducted using the terms child, adolescent, bipolar, depression, psychosis, first-episode psychosis, schizophrenia, attention deficit hyperactivity disorder (ADHD), autism, psychiatric, omega-3, n-3, docosahexaenoic acid and eicosapentaenoic acid. Further studies were identified from the bibliographies of published reviews. RESULTS: One small randomized controlled trial with LCn-3PUFA supplementation in depression in children found a small beneficial effect over placebo. Four placebo-controlled trials showed uncertain benefit of LCn-3PUFA for ADHD. Single placebo-controlled trials showed no benefit in autism or bipolar disorder. There is an absence of studies examining benefit for first-episode psychosis or schizophrenia in children and adolescents. CONCLUSIONS: While children and adolescents are receiving LCn-3PUFA for a range of psychiatric indications, there is only evidence of likely benefit for unipolar depression.