Chemical composition of reindeer forage plants in Svalbard and Norway

Several of the most important reindeer forage plants in Svalbard were analysed for content of minerals (Na, K, P, Ca, Mg, S, Cl, Fe, Cu, Mn, Zn, Mo and Co) and for content of ash, crude protein, crude fiber, ether extracts and nitrogen free extracts. Some forage plants were also examined in in vitro digestibility trials. The results were compared with results from similar analyses of alpine mountain plants from southern Norway. Also freshly voided fecal samples were analysed for the same components as the forage plants.
The Svalbard vegetation had a higher content of Na, Ca, Mg, Cl, Fe and Co, than similar plants from Southern Norway. The content of other elements examined seemed to be more equal in Norway and on Svalbard. Within the Svalbard area plants growing in limestone areas had the highest content of calcium and magnesium. Also plants growing on manured soil below bird cliffs appeared to have high nutritional value. It is furthermore concluded that the closeness to the sea as well as the occurrence of several plants with high mineral content, gave the Svalbard reindeer the possibility to further improve their mineral balance compared with continental reindeer. Also the dietary shift from lichens as a major dietary component in Norway, to mosses on Svalbard, may increase mineral intake, but may also have an inferior effect on digestibility.
Although balance experiments and carcass analyses of minerals in Svalbard reindeer are missing, it is concluded that Svalbard reindeer apparently had adequate intake of most mineral elements. In spite of low standing biomass of reindeer forage plants, the quality of the vegetation seemed to compare favourably with continental reindeer pasture.     

Mortality in Svalbard reindeer

Mortality rates in Svalbard reindeer followed the "U"-shaped pattern, with higher mortality rate among calves and old animals than in middle aged individuals. Assuming a stable population size, the mortality data predict a 16.2% annual mortality and recruitment rate among 6 months and older animals, and a male:female sex ratio of 48.5:51.5 among 1-yr old and older. Both predictions are supported by field data. Female mortality rate increased and differed from the male rate in the age interval 2-4 yr, while the male rate increased sharply and differed permanently from the female rate in the age interval above 6 yr. First and last breeding are thought to cause the increased mortality among 2–4 and 11–13 yr-old females. Increased involvement in rutting activities with age associated with lower grazing activity and depletion of fat reserves probably cause the increasing mortality rate among the 6+ yr males. Maximum life span was 17 yr in females and 12 yr in males. Apart from the unknown but possibly high neonatal calf-mortality, only few animals died during summer or during the rut in autumn. Death among calves, yearlings and most of the females occurred before antler-shedding in May-June. Most of the 2-yr and older males died after antler shedding, which occurs from December among the oldest and during April-May among the younger males. Hence, the major part of the mortality takes place in spring. The lack of visible subcutaneous and femur fat in most carcasses indicated starvation as the major mortality cause.     

Size and composition of the wild reindeer Rangifer tarandus platyrhynchus population in the Southeast Svalbard Nature Reserve

Alendal, E., de Bie, S. and van Wieren, S. E. 1979. Size and composition of the wild reindeer Rangifer tarandus platyrhynchus population in the Southeast Svalbard Nature Reserve. Holarct. Ecol. 2: 101-107. In the summer of 1977 we studied the reindeer population on the islands Barentsøya and Edgeøya in the eastern part of the Svalbard archipelago. A total of 1374 reindeer were observed: 326 animals in the western parts of Barentsøya and 1048 animals on Edgeøya. Considering those parts of Edgeøya which were not visited, the total number of reindeer on Edgeøya was estimated at 1300 animals. The total number of reindeer was lower than in previous years. The decline probably was due to severe winter conditions in 1975/1976 and 1976/1977 confirmed by the fact that many carcasses and few yearlings were observed. Nearly all reindeer occurred on the coastal plains and in the valleys. These areas have the relatively richest vegetation. The average recruitment of the total population (counted) was 15.9%. The adult sex ratio was in favour of females: 59% females versus 41% males. There were differences both in the recruitment and in the adult sex ratio between three distinct areas on Edgeøya and between two on Barentsøya. These differences may be due to dissimilarities in food quality and feeding conditions caused by climate, and by small exchange of reindeer between the areas. The high frequency of shed male antlers on Frankenhalvøya and Talaveraflya, north and south coast of Barentsøya respectively, indicates that these areas belong to the wintering grounds of reindeer on this island. Concentrations of shed female antlers on Barentsøya were less pronounced. The highest frequency was in the areas Sjodalen and Kvistdalen-Talaveraflya in the northwest and south respectively. Females may use these areas as late wintering grounds and possibly as calving areas. The average group size was 2.2 and the aggregation index 3.1. Seventytwo per cent of all groups, containing 48% of all reindeer, fell into group size 1 and 2. Males mostly were observed alone or together with one other animal. Females with calves most frequently occurred in groups of 2 and 4 animals.     

Fiber type composition and enzyme activities of muscles in two models of obese rats

• 1.1. In oxidative (soleus) and glycolytic (extensor digitorum longus) muscles of obese Zucker rats, a significant decrease in the percentage of relative area occupied by glycolytic fibers was observed.
• 2.2. The activity of citrate synthase and β-hydroxy-acyl-CoA-dehydrogenase was significantly higher in muscles of obese than of lean Zucker rats.
• 3.3. In rats, 6 weeks after lesion of the ventromedial hypothalamus, no changes were observed.
• 4.4. This indicates that neither the proportion of oxidative fibers, nor the oxidative capacities are decreased in skeletal muscles of obese rats suggesting that insulin resistance cannot be ascribed to a higher glycolytic-oxidative fiber ratio.

     

Effect of exercise on muscle fibre composition and enzyme activities of skeletal muscles in young rats

Young Wistar rats underwent dynamic (D) or static (S) exercise from the 5th to 35th day after birth. Histochemical and biochemical analysis were performed in the extensor digitorum longus (EDL) and the soleus muscle (SOL). Lactate dehydrogenase (LDH) (regulating anaerobic metabolism) and citrate synthase (CS) and hydroxyacyl-CoA dehydrogenase (HAD) (both regulating aerobic metabolism) activities were determined spectrophotometrically. An increase of the fast oxidative-glycolytic (FOG) muscle fibres was found in the slow SOL muscle in both trained groups, i.e. by 10% in group D and by 7% in group S in comparison with the C group. The EDL muscle fibre distribution did not differ from those of control animals in respect to the slow oxidative (SO) fibre type. A higher percentage of FOG fibres by 19% was found in group D contrary to a decreased number of the fast glycolytic (FG) muscle fibres in this trained group. The greatest increase of CS (EDL 185%, SOL 176%) and HAD (EDL 83%, SOL 178%) activities were found in group D as compared with control group (C). Only small differences were observed in LDH activity. The values of characteristic enzyme activity ratios show that dynamic training resulted in an elevation of oxidative capacity of skeletal muscle, while the static load led preferentially along the glycolytic pathway. It may be concluded that an adaptive response to the training load during early postnatal development is different due to the type of exercise (dynamic or static) and/or the type of skeletal muscle (fast or slow).     

Microsatellite DNA evidence for genetic drift and philopatry in Svalbard reindeer

Mainland populations of Arctic reindeer and caribou Rangifer tarandus often undergo extensive movements, whereas populations on islands tend to be isolated and sedentary. To characterize the genetic consequences of this difference, levels of genetic diversity and subdivision of Svalbard reindeer (R. t. platyrhynchus) from two adjacent areas on Nordenskjiöldland, Spitsbergen were estimated using data from up to 14 microsatellites. The mean number of alleles per locus in Svalbard reindeer was 2.4 and mean expected heterozygosity per locus was 0.36. The latter value was significantly lower than in Canadian caribou and Norwegian reindeer but higher than in some other cervid species. Large samples of females (n = 743) and small samples of males (n = 38) from two sites ≈ 45 km apart showed genetic subdivision, which could be due to local population fluctuations or limited gene flow. To our knowledge, this is the first study to report significant differentiation at microsatellite loci in Rangifer at such short geographical distances. Neither population showed genetic evidence for recent population bottlenecks when loci unbiased with respect to heterozygosity were analysed. In contrast, false signals of a recent bottleneck were detected when loci upwardly biased with respect to heterozygosity were analysed. Thus, Svalbard reindeer appeared to conform to the paradigm of island populations made genetically depauperate by genetic drift.     

Regulation of proteolytic enzyme activities in muscles practice and hypothesis.

Two weeks of immobilization in shortened state caused 50% decrease in muscle mass and an increase in lysosomal proteinase activities. In this study causes of elevated protease activities in muscle are studied. Many factors could play a role in these elevated proteinase activities. We have found that redox state, ATP content, fuel supply and glucocorticoid receptor number were important in this period. Testosterone, insulin or proteinase inhibitors were not proved to play role in elevated proteinase activities. These practical results are explained by the results achieved in other types of cells. We conclude that changes in redox potential and/or oxygen free radical content of muscle elements can cause a post-translational covalent modification of cysteine proteinases and -SH dependent metalloproteinases, leading thereby to their activation. Lysosomal cysteine proteinases can activate procathepsin D that can damage lysosomal cysteine proteinase inhibitors and in another path it activates procathepsin B, L and H reversely. This feed-back regulation and the activation of cysteine proteinases by metalloproteinases might accelerate the proteinase activities in skeletal muscles.     

Sexual dimorphism in the pelvic bones of Svalbard reindeer, Rangifer tarandus platyrhynchus

The determination of sex of carcasses of reindeer and caribou (Rangifer tarandus) is complicated because both sexes normally carry antlers. Growth curves of males and females diverge sufficiently so that the length of long bones can often indicate the sex of a carcass if its age at death is known; results, however, are not always conclusive. Pronounced sexual dimorphism was found in the breadth of the ventro-medial border (rim) of the acetabulum of adult Svalbard reindeer. Measurement of the rim of the acetabulum thus provides a quick and conclusive means for determining the sex of carcasses of these animals. Similar results have been found in several other species of ungulates. Reasons for the dimorphism and for the non-normal distribution of the data for both sexes in reindeer are discussed.     

Effects of density-dependence and climate on the dynamics of a Svalbard reindeer population

To determine the main factors affecting the population dynamics of Svalbard reindeer, we analysed 21 yr of annual censuses, including data on population size, recruitment rate (calves per female) and mortality (number of deaths), from the Reindalen reindeer population. In accordance with previous studies on population dynamics of Svalbard reindeer, we found large inter-annual variation in population size, mortality and recruitment rates within the study area. Population size decreased in years with low recruitment rate as well as high winter mortality and vice versa. Apparently. the fluctuations were due to both direct density-dependent food limitation and variation in winter climate associated with high precipitation and icing of the feeding range. We found no delayed density-dependence or effect of climatic conditions during summer on the population dynamics. The mortality during die-off years was mainly of calves and very old individuals, indicating that the population was more vulnerable to high die oft in years following high recruitment rate. These results suggest an unstable interaction between the reindeer population and its food supply in these predator-free environments.     

Increased mass of reticulo-rumen tissue and contents with advancing age in Svalbard reindeer

Little is known about the effect of age on digestive processes in wild cervids. One potentially important mechanism is that tooth wear alters the occlusal surface topography, causing gradual loss of functionality. Mastication efficiency is crucial to digestion processes among ruminants, as a larger particle size is associated with longer retention times and potentially reduced digestion efficiency. Using data from 49 adult Svalbard reindeer Rangifer tarandus platyrhynchus females, we investigated whether the mass of reticulo-rumen (RR) contents and tissue and the amount of back fat showed age-related changes. Older animals had higher RR content mass than younger individuals. This is consistent with the prediction that altered particle size due to decreased mastication efficiency led to increased rumen retention time either through increased RR capacity or filling. Additional data on RR particle size distribution were available for a subset ( n =30). The correlation between the proportion of small particles (<1.0 mm) and RR contents was much weaker than the correlation between age and RR contents. This suggests that additional factors apart from particle size contribute to the age-related pattern in RR content mass. The mass of RR tissue in older animals was higher than that in younger animals. This possibly reflects an adaptation to the higher organ fill. The amount of back fat decreased with age, suggesting that alterations in digestion-related processes are not sufficient to compensate for reduced mastication efficiency in Svalbard reindeer. Our results present one possible link between foraging, digestive processes and life-history patterns.     

Evidence for a trade-off between early growth and tooth wear in Svalbard reindeer

Ruminants depend on efficient physical degradation of forage through chewing to increase the surface area of the food particles presented to the microflora. Fossil evidence suggests that increased molar height is an adaptation for wear tolerance in dry ecosystems with sparse vegetation, but no study has shown selection pressure for hypsodonty in contemporary ruminants. We explored the relationships between particle size in rumen, tooth wear (scanned molar occlusal topography), age and body mass of female Svalbard reindeer living in an arctic desert at 78 degrees latitude on Svalbard. We predicted that (H1) if the rumen particle size is determined mainly by constraints due to tooth wear, and if tooth wear is mainly a function of age, average particle size in rumen should increase with age. From allometric relations it is known that larger individuals can survive on a lower-quality diet, we therefore predicted (H2) larger particle sizes with increases in (ln) body mass, irrespective of age and wear. Lastly, if there is a trade-off between growth and tooth wear in dry ecosystems (a selection pressure for hypsodonty), we predicted (H3) that teeth of heavier animals should be more worn than those of lighter animals of the same age. The proportion of small particles (<1.0 mm) decreased rapidly with increasing age (consistent with H1). Heavier females within an age class had more worn teeth (consistent with H3) than lighter ones. A close-to-isometric relationship between particle size and body mass suggested that heavier animals partly compensated for reduced tooth efficiency by chewing more. We provide the first evidence of a trade-off between fast early growth and wear (a somatic cost) of a senescence-related trait--the structure and height of the molar--in a wild ruminant inhabiting an arctic desert where selection pressure for increased tooth height is expected. This suggests that foraging conditions are more extreme than the environment in which the species originally evolved.     

Glucose-dependent enzyme activities in different yeast species

Summary The activities of several enzymes involved in the oxidation of ethanol and in the formation of oxaloacetate from acetate were compared in the yeasts Saccharomyces cerevisiae, Hansenula anomala and Rhodotorula glutinis grown on glucose and acetate, respectively. The most striking differences in the regulation of enzyme activities were found for alcohol dehydrogenase, acetaldehyde dehydrogenase, and malate dehydrogenase. The activities of the other enzymes tested behaved rather similar; in all three yeast species the enzymes of the glyoxylic acid by-pass showed the most extensive increase of activity in cells grown on acetate.     

Metagenomics of the Svalbard reindeer rumen microbiome reveals abundance of polysaccharide utilization loci

Lignocellulosic biomass remains a largely untapped source of renewable energy predominantly due to its recalcitrance and an incomplete understanding of how this is overcome in nature. We present here a compositional and comparative analysis of metagenomic data pertaining to a natural biomass-converting ecosystem adapted to austere arctic nutritional conditions, namely the rumen microbiome of Svalbard reindeer (Rangifer tarandus platyrhynchus). Community analysis showed that deeply-branched cellulolytic lineages affiliated to the Bacteroidetes and Firmicutes are dominant, whilst sequence binning methods facilitated the assemblage of metagenomic sequence for a dominant and novel Bacteroidales clade (SRM-1). Analysis of unassembled metagenomic sequence as well as metabolic reconstruction of SRM-1 revealed the presence of multiple polysaccharide utilization loci-like systems (PULs) as well as members of more than 20 glycoside hydrolase and other carbohydrate-active enzyme families targeting various polysaccharides including cellulose, xylan and pectin. Functional screening of cloned metagenome fragments revealed high cellulolytic activity and an abundance of PULs that are rich in endoglucanases (GH5) but devoid of other common enzymes thought to be involved in cellulose degradation. Combining these results with known and partly re-evaluated metagenomic data strongly indicates that much like the human distal gut, the digestive system of herbivores harbours high numbers of deeply branched and as-yet uncultured members of the Bacteroidetes that depend on PUL-like systems for plant biomass degradation.     

The activities of fructose diphosphatase in flight muscles from the bumble-bee and role of this enzyme in heat generation

1. The maximum catalytic activities of fructose diphosphatase from flight muscles of bumble-bees (Bombus spp.) are at least 30-fold those reported for the enzyme from other tissues. The maximum activity of fructose diphosphatase in the flight muscle of any particular bee is similar to that of phosphofructokinase in the same muscle, and the activity of hexokinase is similar to or greater than the activity of phosphofructokinase. There is no detectable activity of glucose 6-phosphatase and only a very low activity of glucose 6-phosphate dehydrogenase in these muscles. The activities of both fructose diphosphatase and phosphofructokinase vary inversely with the body weight of the bee, whereas that of hexokinase is relatively constant. 2. There is no significant hydrolysis of fructose 1-phosphate, fructose 6-phosphate, glucose 1,6-diphosphate and glycerol 3-phosphate by extracts of bumble-bee flight muscle. 3. Fructose 1,6-diphosphatase from bumble-bee flight muscle and from other muscles is inhibited by Mn(2+) and univalent cations; the potency of inhibition by the latter varies in the order Li(+)>Na(+)>K(+). However, the fructose diphosphatase from bumble-bee flight muscle is different from the enzyme from other tissues in that it is not inhibited by AMP. 4. The contents of ATP, hexose monophosphates, fructose diphosphate and triose phosphates in bumble-bee flight muscle showed no significant changes between rest and flight. 5. It is proposed that both fructose diphosphatase and phosphofructokinase are simultaneously active and catalyse a cycle between fructose 6-phosphate and fructose diphosphate in resting bumble-bee flight muscle. Such a cycle would produce continuous hydrolysis of ATP, with the release of energy as heat, which would help to maintain the thoracic temperature during rest periods at a level adequate for flight.     

Identification by polymerase chain reaction (PCR) of Marshallagia marshalli and Ostertagia gruehneri from Svalbard reindeer

A polymerase chain reaction (PCR) assay to identify two common abomasal nematodes Marshallagia marshalli and Ostertagia gruehneri of Svalbard reindeer was developed. Species-specific PCR primers were designed from internal transcribed spacer (ITS)-2 sequences of rDNA and validated using morphologically identified adult male and female nematodes. Using the species-specific primers, a 110 bp fragment was amplified from M. marshalli and its minor morph Marshallagia occidentalis and a 149 bp fragment was amplified from Ostertagia gruehneri and its minor morph Ostertagia arctica. No PCR products were amplified from the third rare species, Teladorsagia circumcincta, or DNA from the reindeer host. The assay provides a useful tool to estimate species composition for both sexes in this nematode community.     

Rumen microbial diversity in Svalbard reindeer, with particular emphasis on methanogenic archaea

Ruminal methanogens, bacteria and ciliate protozoa of Svalbard reindeer grazing natural pastures in October (late fall) and April (late winter) were investigated using molecular-based approaches. The appetite of the Svalbard reindeer peaks in August (summer) and is at its lowest in March (winter). Microbial numbers, quantified by real-time PCR, did not change significantly between October and April, when food intakes are at similar levels, although the numbers of methanogens tended to be higher in October ( P =0.074), and ciliate numbers tended to be higher in April ( P= 0.055). Similarly, no change was detected in the bacterial and protozoal population composition by rRNA gene-based denaturing gradient gel electrophoresis analysis. Dominant methanogens were identified using a 16S rRNA gene library (97 clones) prepared from pooled PCR products from reindeer on October pasture ( n =5). Eleven of the 22 distinct operational taxonomic units (OTUs) generated exhibited a high degree of sequence similarity to methanogens affiliated with Methanobacteriales (eight OTUs), Methanomicrobiales (one OTU) and Methanosarcinales (two OTUs). The remaining 11 OTUs (53% of the clones) were associated with a cluster of uncultivated ruminal archaea. This study has provided important insights into the rumen microbiome of a high-arctic herbivorous animal living under harsh nutritional conditions, and evidence suggesting that host type affects the population size of ruminal methanogens.     

Soil enzyme activities and organic matter composition in a turfgrass chronosequence

Highly managed turfgrass systems accumulate considerable soil organic C, which supports a diverse and robust soil microbial community. Degradation of this soil organic C is mediated by a suite of soil enzymes. The relationship between these enzyme activities and the quality of soil organic C is central to understanding the dynamics of soil organic matter. We examined the activities of several soil enzymes involved in microbial C acquisition, including β-glucosidase, N-acetyl-β-glucosaminidase, cellulase, chitinase, and phenol oxidase, and characterized the chemical composition of soil organic matter using Fourier transform infrared spectroscopy (FTIR) in a turfgrass chronosequence (1–95 years old) and adjacent native pines. Non-metric multidimensional scaling analysis showed that the chemical composition of soil organic matter varied with turf age and land use (turf versus pines). Using the polysaccharide peak (1,060 cm⁻¹) as a reference, both aliphatic (2,930 cm⁻¹) and carboxylic (1,650 and 1,380 cm⁻¹) compounds increased with turf age, indicating that soil organic matter became more recalcitrant. Soil enzyme activities per unit soil mass increased with turf age and were correlated to soil C content. Most soil enzyme activities in native pines were similar to those in young turf, but the cellulase activity was similar to or greater than the activity in old turfgrass systems. On a soil C basis, however, the activities of N-acetyl-β-glucosaminidase and cellulase decreased with turf age; this reduction was correlated to the relative changes in the chemical composition of soil organic matter. We observed that the chemical composition of soil organic matter was significantly correlated with the enzyme activity profile when expressed per unit microbial biomass C, but not per unit soil organic C. Our results suggest that chemical composition of soil organic matter changes with turf age and this change partially determines the relative abundance of C-degrading soil enzymes, likely through the influence on microbial community composition.