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Organismal metabolic rates reflect the interaction of environmental and physiological factors. Thus, calcifying organisms that record growth history can provide insight into both the ancient environments in which they lived and their own physiology and life history. However, interpreting them requires understanding which environmental factors have the greatest influence on growth rate and the extent to which evolutionary history constrains growth rates across lineages. We integrated satellite measurements of sea-surface temperature and chlorophyll-a concentration with a database of growth coefficients, body sizes, and life spans for 692 populations of living marine bivalves in 195 species, set within the context of a new maximum-likelihood phylogeny of bivalves. We find that environmental predictors overall explain only a small proportion of variation in growth coefficient across all species; temperature is a better predictor of growth coefficient than food supply, and growth coefficient is somewhat more variable at higher summer temperatures. Growth coefficients exhibit moderate phylogenetic signal, and taxonomic membership is a stronger predictor of growth coefficient than any environmental predictor, but phylogenetic inertia cannot fully explain the disjunction between our findings and the extensive body of work demonstrating strong environmental control on growth rates within taxa. Accounting for evolutionary history is critical when considering shells as historical archives. The weak relationship between variation in food supply and variation in growth coefficient in our data set is inconsistent with the hypothesis that the increase in mean body size through the Phanerozoic was driven by increasing productivity enabling faster growth rates.
In early Christian literature the death of Judas is broadly understood as a fitting end to the life of the betrayer of Jesus. Papias’ description of Judas’ death can be illuminated by comparison with ancient biographical and medical literature, in which oedema and parasitic infections are a consequence of greed, and also apocalyptic texts, in which worms become an emblematic form of divine punishment after death. Viewed in this context the death of Judas serves a pedagogical function as a warning about the dangers of greed.
Surface sediments (n=85) from a 160-km river-estuarine transect of the Clyde, UK, were analysed for total mercury (Hg), saturated hydrocarbons and unresolved complex mixtures (UCMs) of hydrocarbons. Results show that sediment-Hg concentration ranges from 0.01 to 1.38mgkg–1 (mean 0.20mgkg–1) and a spatial trend in Hg-content low–high–low–high, from freshwater source, to Glasgow, to estuary, is evident. In summary, sediment-Hg content is low in the upper Clyde (mean of 0.05Hg mgkg–1), whereas sediments from the Clyde in urbanised Glasgow have higher Hg concentrations (0.04 to 1.26mgkg–1; mean 0.45mgkg–1), and the inner estuary sediments contain less Hg (mean 0.06mgkg–1). The highest mean sediment Hg (0.65mgkg–1) found in the outer estuary is attributed to historical anthropogenic activities. A significant positive Spearman correlation between Hg and total organic carbon is observed throughout the river estuary (0.86; P<0.001). Comparison with Marine Scotland guidelines suggests that no sites exceed the 1.5mgkg–1 criterion (Action Level 2); 22 fall between 0.25 and 1.5mgkg–1 dry wt. (Action Level 1) and 63 are of no immediate concern (<0.25mgkg–1 dry wt.). Saturated (n-alkane) hydrocarbons in the upper Clyde are of natural terrestrial origin. By contrast, the urbanised Glasgow reaches and outer estuary are characterised by pronounced and potentially toxic UCM concentrations in sediments (380–914mg/kg and 103–247mgkg–1, respectively), suggesting anthropogenic inputs such as biodegraded crude oil, sewage discharge and/or urban run-off.
Poverty brome (Bromus sterilis L.) [sterile or barren brome, syn. Anisantha sterilis (L.) Nevski] is a problematic UK arable weed. There are currently no confirmed cases of glyphosate resistance in any weed species in the United Kingdom or in B. sterilis worldwide. However, there are reports of poor control by glyphosate in this species. Here, we report experiments to confirm the suspected on-farm resistance of B. sterilis populations to glyphosate. Glyphosate screening and dose–response experiments established that glyphosate sensitivity of three UK B. sterilis populations exhibiting poor field control is outside the normal range of sensitivity of 30 sensitive populations and adjacent unexposed populations. Control of sensitive populations ranged from 49% to 82% and for suspected resistant populations from 21% to 30%. Dose–response ED50 values of sensitive populations ranged between 241 and 313 g ai ha−1; corresponding values of suspected resistant populations ranged between 420 and 810 g ha−1, and resistance indices ranged from 1.55 to 4.5. Suspected resistant populations were incompletely controlled at the recommended field rate of glyphosate (540 g ha−1), while adjacent unexposed populations were completely controlled. We conclude that some UK populations of B. sterilis have reduced glyphosate sensitivity and are in the process of evolving resistance. This is the first reported case of reduced glyphosate sensitivity in any UK weed species and in B. sterilis worldwide. This, coupled with increasing glyphosate use, highlights the need for increased vigilance and monitoring for glyphosate resistance in the United Kingdom.
An experiment was carried out to examine the effects of offering beef cattle five silage diets. These were perennial ryegrass silage (PRGS) as the sole forage, tall fescue/perennial ryegrass silage (FGS) as the sole forage, PRGS in a 50:50 ratio on a dry matter (DM) basis with lupin/triticale silage (LTS), lupin/wheat silage (LWS) and pea/oat silage (POS). Each of the five silage diets was supplemented with 4 and 7 kg of concentrates/head/day in a five silages × two concentrate intakes factorial design. A total of 90 cattle were used in the 121-day experiment. The grass silages were of medium digestibility and were well preserved. The legume/cereal silages had high ammonia N, high acetic acid, low lactic acid, low butyric acid and low digestible organic matter concentrations (542, 562 and 502 g/kg DM for LTS, LWS and POS, respectively). Silage treatment did not significantly affect liveweight gain, carcass gain, carcass characteristics, the instrumental assessment of meat quality or fatty acid composition of the M. longissimus dorsi muscle. In view of the low yields of the legume/cereal crops, it is concluded that the inclusion of spring-sown legume/cereal silages in the diets of beef cattle is unlikely to be advantageous.
An experiment was carried out to examine the effects of offering beef steers grass silage (GS) as the sole forage, lupins/triticale silage (LTS) as the sole forage, a mixture of LTS and GS at a ratio of 70:30 on a dry matter (DM) basis, vetch/barley silage (VBS) as the sole forage, a mixture of VBS and GS at a ratio of 70:30 on a DM basis, giving a total of five silage diets. Each of the five silage diets was supplemented with 2 and 5 kg of concentrates/head/day in a 5 × 2 factorial design to evaluate the five silages at two levels of concentrate intake and to examine possible interactions between silage type and concentrate intake. A total of 80 beef steers were used in the 122-day experiment. The GS was well preserved while the whole crop cereal/legume silages had high ammonia-nitrogen (N) concentrations, low lactic acid concentrations and low butyric acid concentrations For GS, LTS, LTS/GS, VBS and VBS/GS, respectively, silage DM intakes were 6.5, 7.0, 7.2, 6.1 and 6.6 (s.e.d. 0.55) kg/day and live weight gains were 0.94, 0.72, 0.63, 0.65 and 0.73 (s.e.d. 0.076) kg/day. Silage type did not affect carcass fatness, the colour or tenderness of meat or the fatty acid composition of the intramuscular fat in the longissimus dorsi muscle.
Agriculture is one of the major sources of methane in the UK and the major contribution is that from the ruminant animal. Most current inventories include emissions from growing and adult cattle and it has been assumed that the young calf contributes little to the methane flux. There is a dearth of information for young cattle (65-110 kg liveweight) and the objective here was to provide methane data for this group of ruminants to assist in improving the UK inventories for methane.
The gas production (GP) technique has previously been used to estimate the gas volume (fermentable energy (FE)) of compound feed ingredients for ruminants (Newbold et al., 1996). It was shown that the FE content of feed mixtures was represented by the combination of the total gas from the incubation of the individual feeds. However this additivity might not be consistent throughout the incubation period. The objectives were to test whether 1. other GP parameters give better estimates of FE for simple mixtures and are they additive; 2. whether organic matter apparently degraded in the rumen (OMADR) explain differences in GP; and 3. to find out if there are any other better measures than OMADR for estimating FE.
Agriculture is one of the major sources of methane in the UK and the major contribution is that from the ruminant animal. Most current inventories include evaluations of emission rates determined from ammals in respiration chambers. Methodolgy has been developed at IGER, North Wyke which enables measurements to be made with grazing animals (tunnel system). Preliminary measurements have indicated that methane emissions from grazing sheep in the tunnel system were lower than reported values for zero-grazed grass determined in chambers. The objective was to determine if these observed differences were a result of methodological differences.
Nitrogen-deficient fibrous crop residues are widely used as basal diets in less developed countries, particularly in dry seasons when alternative foods are often in short supply. One approach to improving animal performance on crop residue based diets is to include a supplement of improved quality food to provide fermentable protein and energy. There are no established in vitro methods for investigating interactions between foods but the in vitro gas production method shows promise in this regard (Prasad et al., 1994). This paper describes the interactions observed in vitro; an accompanying paper (Murray et al., 1998) describes in vivo responses to supplementation and relationships between in vitro and in vivo data.
The in situ and in vitro techniques have been adopted to estimate the degradability of organic matter (OM) in the rumen on the basis that this provides an estimate of ATP for microbial protein synthesis. However this assumption may be incorrect since ATP production requires the fermentation of degraded carbohydrate and Beever (1993) has shown that some degraded hexose can be used synthetically without ATP production. In addition, degraded OM from protein is likely to produce less ATP than the same amount of degraded carbohydrate. The gas production (GP) technique measures end products of fermentation and may be a better guide to ATP production. On the assumption that the in situ and in vitro techniques provide satisfactory estimation of OM degradability, the work discussed here used the GP technique to estimate the effective unfermentable OM fraction of the degraded OM (EUFDOM) for a range of concentrate foods.
When a food is ingested by a ruminant animal, the carbohydrate fraction of the food is fermented by the rumen micro-organisms to produce gas (predominantly carbon dioxide and methane) as well as volatile fatty acids (VFA). The gas production technique simulates this fermentation process and provides an estimate of both the rate and extent of fermentation. Comparing the gas production (GP) profiles of foods enables a comparison to be made of the fermentative characteristics of different foods. However, the technique uses a bicarbonate-based medium system with the rumen liquor. This complicates the GP profile because of the production of ‘indirect’ gas resulting from the reaction between the VFA and the bicarbonate ions.
Beuvink and Spoelstra (1992) measured the volume of gas produced from buffered rumen fluid when known amounts of VFA were added and observed that 20·8 ml gas were released per mmol VFA. However, there is variation between laboratories in terms of the composition of the medium that is used. Even when the same medium is used, significant differences have been observed in the GP profile when different types of apparatus were employed (Rymer and Givens, 1997). Media are gassed with carbon dioxide before they are added to the gas production system and it is possible that the concentration of carbon dioxide dissolved in the medium varies between experiments. The objective of this experiment, therefore, was to determine whether the volume of indirect gas produced was affected by the composition of the medium, the addition of carbon dioxide, and the technique employed to measure gas production.
Pell and Schofield (1993) described a gas production technique where cumulative pressure is related to gas production and hence organic matter (OM) fermentation. This technique has been used to describe rates of carbohydrate degradation for use in the Cornell net carbohydrate and protein system (CNCPS, Barry et al., 1994). Increasingly the CNCPS model is being utilized in the United Kingdom (UK) to ration dairy cows and, as a result, a UK foodstuff database has been developed containing the chemical description of the protein and carbohydrate pools. It was necessary to establish whether the gas production technique could be reproduced in a UK laboratory in order to provide rates of fermentation of the carbohydrate pools. Gas production techniques commonly used in the UK do not allow the vessel gas pressure to accumulate so a comparison of methodology was required.
Fermentable energy (FE) was defined in the latest United Kingdom metabolizable protein system as energy available for microbial protein growth and multiplication in the rumen (Agricultural and Food Research Council, 1992). In this system the FE value was calculated by subtracting the metabolizable energy (ME) of fat and ME of any fermentation products from the ME of the food. This estimation is indirect and largely based on whole tract digestion data, thus it can not take into account the influence of rumen outflow, fermentation and degradation rate and digesta retention time in the rumen. In addition, this approach does not take into account undegradable protein and /or starch. As a result, the precision of the FE values are questionable. Therefore a precise, accurate, rapid, cheap and direct technique to measure FE from food ingredients should be developed. Such a technique should consider the factors mentioned above. This work evaluated the ability of four techniques to estimate the FE value of concentrate foods for ruminants.
Fat content is one of the main factors affecting the degradability and fermentability characteristics of oil-rich foods estimated by means of the in situ, in vitro and gas production techniques. Filtered fat, considered degraded/fermented, is of limited value to the rumen microbes and may inhibit fermentation. Pre-extraction of oil may be one way to solve this problem. The rumen organic matter degradability (OMD) and fermentability (FOM) of concentrate foods were evaluated in this study with and without oil extraction.
Whilst it is recognized that most foods contain a number of different carbohydrate pools most applications of the gas production technique do not allow them to be differentiated despite their likely different nutritional attributes. Schofield and Pell (1995) reported that improved fermentation kinetics of the carbohydrate pools could be obtained by making gas production measurements on the whole food and on its neutral-detergent fibre (NDF) fraction, the data on the neutral-detergent solubles (NDS) being calculated by difference. More recently Doane et al. (1996) proposed an expansion of this to include incubation of the ethanol insoluble residue, to enable the NDS fraction of the food to be separated into a soluble carbohydrate and organic acids fraction and a starch and pectin fraction. Another approach is that of Groot et al. (1996) who used a multiphasic model of whole food gas production to show that the gas is produced from more than one food fraction. The objective of the present work was to combine these two approaches to examine the value of the multiphasic model applied to gas production from the isolated NDF and NDS fractions.
Tenderness can be considered as a function of three components: connective tissue content/composition, sarcomere length and proteolysis of the myofibrillar proteins (ageing) (Koohmaraie, 2002). Improvement of sarcomere length and proteolysis can be achieved through optimal processing (e.g. hanging and aging; Thompson, 2006). The main technique that improves the sarcomere length is tenderstretch hanging. This technique increases the tension of the hindlimb and loin muscles avoiding the contraction of the fibers at rigor (Bouton, 1973). In this experiment the aim was, under commercial conditions, to compare two methods of tenderstretch hanging and to examine the potential to improve the tenderness of lamb muscles.
Meat from Holstein-Friesian bulls, which are bred for dairy traits, is generally regarded as low quality and is usually destined for the commodity (mince) market. However, given their ready availability as a by-product from the dairy herd, it is important to determine if meat from these animals would be suited to higher-priced markets. Furthermore, meat from bulls is generally considered to be lower quality than that from steers, though there is a paucity of data comparing meat from both sources. Hence, the objective of this study was to evaluate the effect of slaughter weight on meat quality characteristics of Holstein-Friesian bulls and steers offered a cereal-based ration.
A considerable proportion of beef produced in the UK is a byproduct of the dairy industry. Young animals from this source are generally regarded as low in quality and meat from animals of this type is usually destined for the commodity minced beef market. The objective of the present study was to evaluate the effect of slaughter weight on sensory characteristics of meat from Holstein-Friesian bulls and steers offered a cereal-based ration.