Effects of supplemental rumen-protected conjugated linoleic acid or corn oil on fatty acid composition of adipose tissues in beef cattle

Thirty-six Angus x Hereford heifers (365 +/- 60 kg) were used to determine the effects of supplemental dietary lipid sources on fatty acid composition of i.m., perianal (p.a.), and s.c. lipid depots. Lipid was supplied to diets as either corn oil or a rumen-protected conjugated linoleic acid (CLA) salt for two specific treatment periods of either the final 32 or 60 d on feed. Following an initial 56-d feeding period, heifers were fed one of three dietary treatments (DM basis): 1) basal diet containing 88% concentrate and 12% grass hay (CON), 2) basal diet plus 4% corn oil (OIL), or 3) basal diet plus 2% rumen-protected CLA salt (RPCLA) containing 31% CLA. The trans-10, cis-12 CLA concentration was greatest (P < 0.05) for heifers fed RPCLA and OIL diets and least (P < 0.05) for CON, regardless of time on dietary treatment. Heifers fed supplemental RPCLA had greater (P < 0.05) total CLA content than either CON- or OIL-fed heifers. Adipose tissue concentration of trans-11 vaccenic acid (TVA) was less (P < 0.05) for CON than OIL or RPCLA, which did not differ (P > 0.05). Percentages of C18:1 trans-10 were least (P < 0.05) in i.m. lipid compared with p.a. and s.c., which did not differ (P > 0.05). Following 60 d of lipid supplementation, heifers fed OIL and RPCLA had lower (P < 0.05) concentrations of oleic acid and total monounsaturated fatty acids (MUFA) compared with CON. The ratio of cis-9, trans-11 CLA:TVA was higher (P < 0.05) for heifers fed 60 vs. 32 d, but did not differ (P > 0.05) between adipose depots. Feeding OIL increased (P < 0.05) adipose concentration of C18:2 fatty acid, whereas feeding RPCLA increased (P < 0.05) total CLA isomers by 22%. Intramuscular lipid contained the lowest (P < 0.05) percentage of cis-9, trans-11 CLA, total CLA, C18:1 cis-9, C18:1 trans-10, and TVA. Total CLA and cis-9, trans-11 CLA isomers were increased (P < 0.05) in p.a. and s.c. adipose depots, whereas i.m. adipose tissue contained increased (P < 0.05) amounts of total PUFA. Results from this study indicate that short-term lipid supplementation to feedlot cattle can increase adipose tissue CLA concentrations, but only marginally (8.3 to 17.5%). Moreover, observed decreases in oleic acid and total MUFA concentrations of adipose tissues from heifers fed rumen-protected CLA or corn oil suggest that lipid supplementation may decrease delta9 desaturase activity in adipose tissues, which in turn would lower the conversion of TVA to cis-9, trans-11 CLA isomer.     

Influence of threonine intake on whole-body protein deposition and threonine utilization in growing pigs fed purified diets.

The relationship between available threonine (Thr) intake and whole-body protein deposition (PD) was established using the serial slaughter method in 36 individually housed growing gilts between 39 and 77 kg live BW. Pigs were prescreened for their maximum PD (PDmax), based on a N balance starting at 25 kg BW while they consumed semi-ad libitum a nonlimiting diet. Pigs were fed combinations of a casein and cornstarch-based diet that was confirmed to be first-limiting in Thr and a protein-free diet starting at approximately 30 kg BW. Casein-bound Thr was provided at 60, 70, 80, 90, 100, or 120% of estimated Thr requirements for PDmax. Energy intake was kept constant across treatments and exceeded requirements for PDmax. Pigs were fed three equal meals per day; feeding levels were adjusted weekly based on BW. Pigs were killed at either 39 kg BW (n = 2 per treatment) or 77 kg BW (n = 4 per treatment) for determining chemical body composition. Composition of 39-kg BW pigs was not different across treatments (P > 0.10); therefore, an overall mean initial body composition was used to estimate body protein content at the initial BW. Across treatments, mean daily ME intake was 25.3 (SE 0.08) MJ/d and did not differ (P > 0.10) among treatments. Average daily true ileal digestible Thr intake varied between 5.33 and 9.66 g/d, representing means for pigs on the lowest and the highest Thr intakes, respectively. Mean PD was 93, 102, 118, 124, 139, and 133 (SE 4.2) g/d for pigs on the six respective treatments. Dietary Thr intake did not influence (P > 0.10) Thr content of body protein at the final BW or the partitioning of body protein between carcass, viscera, and blood. The efficiency of Thr utilization for PD was lowest (P < 0.05) at the highest Thr intake level and highest (P < 0.05) at the lowest Thr intake level. It was similar (P > 0.10) at the four intermediate Thr intake levels, in which the relationship between true ileal digestible Thr intake and PD was linear. Based on these four treatments, calculated Thr disappearance, which is closely associated with inevitable Thr catabolism, was 23.5 (SE 0.55)% of available Thr intake. This value is consistent with an efficiency of using available Thr intake above maintenance Thr requirements (54 mg/kg BW0.75) for Thr retention with PD of 73.4 (SE 1.11)%. Based on N balances conducted at approximately 40 and 75 kg BW, the marginal efficiency of Thr utilization was not influenced by BW.     

Crown plasticity in mixed forests—Quantifying asymmetry as a measure of competition using terrestrial laser scanning

Interspecific competition is a key process determining the dynamics of mixed forest stands and influencing the yield of multispecies tree plantations. Trees can respond to competitive pressure from neighbors by crown plasticity, thereby avoiding competition. We employed a high-resolution ground-based laser scanner to analyze the 3-dimensional extensions and shape of the tree crowns in a near-natural broad-leaved mixed forest in order to quantify the direction and degree of crown asymmetry of 15 trees (Fagus sylvatica, Fraxinus excelsior, Carpinus betulus) in detail. We also scanned the direct neighbors and analyzed the distance of their crown centres and the crown shape with the aim to predict the crown asymmetry of the focal tree from competition-relevant attributes of its neighbors. It was found that the combination of two parameters, one summarizing the size of the neighbor (DBH) and one describing the distance to the neighbor tree (HD), was most suitable for characterizing the strength of the competitive interaction exerted on a target tree by a given neighbor. By summing up the virtual competitive pressure of all neighbors in a single competitive pressure vector, we were able to predict the direction of crown asymmetry of the focal tree with an accuracy of 96° on the full circle (360°).The competitive pressure model was equally applicable to beech, ash and hornbeam trees and may generate valuable insight into competitive interactions among tree crowns in mixed stands, provided that sufficiently precise data on the shape and position of the tree crowns is available. Multiple-aspect laser-scanning proved to be an accurate and practicable approach for analyzing the complex 3-dimensional shape of the tree crowns, needed to quantify the plasticity of growth processes in the canopy. We conclude that the laser-based analysis of crown plasticity offers the opportunity to achieve a better understanding of the dynamics of canopy space exploration and also may produce valuable advice for the silvicultural management of mixed stands.     

Serological visualization of interleukin 2

Interleukin 2, a lymphokine that acts as a second signal of cellular immune response by way of its action as a T-cell growth factor, was morphologically identified by immunoperoxidase staining. With the use of a monoclonal antibody to interleukin 2 and several complex-forming antisera, the lymphokine was readily distinguished in cytocentrifuge preparations of peripheral blood leukocytes stimulated with a T-cell mitogen. When preparations of cloned interleukin 2 producer and responder cells were stained by the same procedures, discrete patterns of both responder and producer cell phenotypes were revealed. Interleukin 2 producer T cells exhibited a characteristic intense, ringlike cytoplasmic staining, whereas the responder cells (as exemplified by interleukin 2-dependent cell lines) exhibited a less intensive, spotlike membrane staining. In addition, intense membrane localization of interleukin 2, reminiscent of potential capping phenomena, could be observed in stained preparations of cloned responder cells.     

Failure of beta-adrenergic receptor blockade to prevent arrhythmias induced by sympathetic nerve stimulation

Cardiac arrhythmias produced by electrical stimulation of the ventrolateral cardiac sympathetic nerve in dogs were not blocked by the combined administration of propranolol and practolol in amounts that completely blocked cardiac beta-adrenergic receptors. Blockade of cardiac alpha-adrenergic receptors, as well as cardiac cholinergic receptors, also had no influence on the arrhythmias. These results suggest that the adrenergic neuroeffector junction is fundamentally different from any hitherto described, differing perhaps in the neurotransmitter involved or in the nature of the receptor.     

Estimation of the Body Weight of Icelandic Horses

The body weight of horses is an interesting variable for horse owners, as well as for veterinarians. It is useful to have methods of estimation like weight tape or formula, rather than visual estimation, when a weight scale is not available. Different methods of weight estimation exist for adult horses, but to date, there has been no validation of these methods in Icelandic horses. Therefore, three different methods of weight determination (weight scale, weight tape, and weight formula) were compared in this study to investigate whether it is possible to obtain reliable weight measurements of Icelandic horses by using an estimation method. Both the weight pursuant to weight tape and pursuant to weight formula showed no significant differences (P = 1.00 and P = 0.37, respectively) from the actual weight. The correlation between estimated and actual weights was r = 0.94 for weight tape and r = 0.93 for weight formula. However, the differences between the estimated and actual weights were smallest when estimated using an adjusted weight formula: weight (kg) = girth² × length (both in cm)/11,400. In conclusion, the body weight of Icelandic horses can be estimated from the measurements of body girth and length, and weight tape also seems to be a suitable method.     

Compositional changes of forest-floor vegetation in young stands of Norway spruce as an effect of repeated fertilisation

Forestry practices that aim to increase biomass production may mitigate climate change through increased carbon sequestration and the potential of substituting fossil fuels with renewable biofuels. Fertilising young stands of Norway spruce in Sweden have shown to increase tree growth by more than 200%. Fertilisation, however, also has other effects on forest ecosystems. Here, we studied the response of the species composition of forest-floor vegetation to three different frequencies of fertilisation in young stands of Norway spruce. Fertiliser was applied every year, every second year or every third year. The total amount of N ranged from 425 kg ha⁻¹ to 625 kg ha⁻¹, in combination with P, K, Ca, Mg, S, Mn, Zi, B and Cu. The largest effects of the fertilisation were found among bryophytes and lichens, which lost substantial cover. Unexpectedly, Deschampsia flexuosa, commonly known to be favoured by fertilisation, was negatively affected. Species that increased in frequency were Oxalis acetosella, Brachythecium sp. and Plagiothecium sp. Decreased availability of light, as an indirect effect of fertilisation through increased tree canopy cover, was found to be the most important factor behind the change in species composition of vascular plants. The total cover of bryophytes, however, did not show any significant response to the changes in canopy cover, indicating that the effects seen in this group may be a result of more direct effects of the fertiliser. Few significant differences were found between the two most intensive fertilisation frequencies, although fertilisation every third year was often distinguished from both the control and the other fertilised treatments. Even though the effects at the stand level were substantial, the effects on biodiversity and function of ecosystems on a landscape or regional level need further investigation.     

Value of forest information

Traditionally, the quality of forest inventory data has been measured with root mean square error of interesting variables. In many occasions, however, even this information has not been available for all variables of interest, as the main focus has always been on the accuracy of timber volume estimates. In recent years, the quality of data as a basis for decision-making has also been considered, using so-called cost-plus-loss analysis. In such analysis, the optimal data acquisition method is defined to be the one which minimizes the total costs of inventory, i.e., the direct inventory costs and the losses due to suboptimal decisions based on incorrect data. It would, however, be possible to go even further, and estimate the value of certain information, or even information concerning a certain forest variable/parameter in decision-making. This is possible when utilizing Bayesian decision theory. It would enable inventory researchers to concentrate on important issues, and managers to invest optimally on data acquisition process. This review presents the research carried out in valuation of information in different fields and discusses the possibilities to use it in forestry applications.