Gut microbes limit growth in house sparrow nestlings (Passer domesticus) but not through limitations in digestive capacity

Recent research often lauds the services and beneficial effects of host‐associated microbes on animals. However, hosting these microbes may come at a cost. For example, germ‐free and antibiotic‐treated birds generally grow faster than their conventional counterparts. In the wild, juvenile body size is correlated with survival, so hosting a microbiota may incur a fitness cost. Avian altricial nestlings represent an interesting study system in which to investigate these interactions, given that they exhibit the fastest growth rates among vertebrates, and growth is limited by their digestive capacity. We investigated whether reduction and restructuring of the microbiota by antibiotic treatment would: (i) increase growth and food conversion efficiency in nestling house sparrows (Passer domesticus); (ii) alter aspects of gut anatomy or function (particularly activities of digestive carbohydrases and their regulation in response to dietary change); and (iii) whether there were correlations between relative abundances of microbial taxa, digestive function and nestling growth. Antibiotic treatment significantly increased growth and food conversion efficiency in nestlings. Antibiotics did not alter aspects of gut anatomy that we considered but depressed intestinal maltase activity. There were no significant correlations between abundances of microbial taxa and aspects of host physiology. Overall, we conclude that microbial‐induced growth limitation in developing birds is not driven by interactions with digestive capacity. Rather, decreased energetic and material costs of immune function or beneficial effects from microbes enriched under antibiotic treatment may underlie these effects. Understanding the costs and tradeoffs of hosting gut microbial communities represents an avenue of future research.     

Serological evidence for the co‐circulation of two lineages of influenza D viruses in equine populations of the Midwest United States

Influenza D virus (IDV) is a newly described influenza type of the Orthomyxoviridae virus family that was first isolated from diseased swine in 2011 and has subsequently been detected in cattle around the world in 2014. In addition, serological evidence for IDV infection in humans has been recently established. Despite all the progress, the full range of susceptible hosts for this novel virus has yet to be determined, but includes swine, bovine, small ruminants and human. This study was designed to determine if equine is a possible host to this newly emerging influenza virus. Three hundred and sixty‐four equine serum samples were collected in 2015 from 141 farms within the Midwestern United States. Serum samples were examined using hemagglutination inhibition (HI) assay against two established IDV lineages (D/OK and D/660) and one IDV‐related human ICV lineage (C/JHB). Results of this study showed 44 (44 of 364, 12%) samples positive for antibodies against D/OK, 39 (39 of 364, 11%) samples positive for antibodies against D/660, and 41 (41 of 364, 11%) samples positive for antibodies against C/JHB. A subset of these samples was further confirmed via microtitre neutralization (MN) assay. Our data demonstrated that horses are susceptible to two lineages of IDV, and that these viruses were present in equine populations throughout multiple Midwestern states of the United States. These findings continue to support the need for further surveillance of IDV viruses in agricultural species to work towards a better understanding of the full host range and natural reservoirs of influenza D virus.     

NOTICE TO CONTRIBUTORS TO THE SOUTH AFRICAN FORESTRY JOURNAL

The role of root pruning practices in containerised forestry seedling propagation is often ignored or poorly understood. Root pruning is used to reduce the incidence of potential container-induced deformities.

Typical root deformities of container-grown seedlings and methods of correcting them are reviewed. Correct practices are largely being followed by South African forest seedling propagation nurseries.     

Influence of landscape structure on reef fish assemblages

Management of tropical marine environments calls for interdisciplinary studies and innovative methodologies that consider processes occurring over broad spatial scales. We investigated relationships between landscape structure and reef fish assemblage structure in the US Virgin Islands. Measures of landscape structure were transformed into a reduced set of composite indices using principal component analyses (PCA) to synthesize data on the spatial patterning of the landscape structure of the study reefs. However, composite indices (e.g., habitat diversity) were not particularly informative for predicting reef fish assemblage structure. Rather, relationships were interpreted more easily when functional groups of fishes were related to individual habitat features. In particular, multiple reef fish parameters were strongly associated with reef context. Fishes responded to benthic habitat structure at multiple spatial scales, with various groups of fishes each correlated to a unique suite of variables. Accordingly, future experiments should be designed to test functional relationships based on the ecology of the organisms of interest. Our study demonstrates that landscape-scale habitat features influence reef fish communities, illustrating promise in applying a landscape ecology approach to better understand factors that structure coral reef ecosystems. Furthermore, our findings may prove useful in design of spatially-based conservation approaches such as marine protected areas (MPAs), because landscape-scale metrics may serve as proxies for areas with high species diversity and abundance within the coral reef landscape.

     

A new lupane caffeoyl ester from Hippocratea volubilis

The extract of the rootbark of Hippocratea volubilis afforded a new triterpene caffeoyl ester, lupeol caffeate (1). Its structure was determined by means of spectroscopic evidence.     

Individual tree diameter increment model for managed even-aged stands of ponderosa pine throughout the western United States using a multilevel linear mixed effects model

A diameter increment model is developed and evaluated for individual trees of ponderosa pine throughout the species range in the United States using a multilevel linear mixed model. Stochastic variability is broken down among period, locale, plot, tree and within-tree components. Covariates acting at tree and stand level, as breast height diameter, density, site index, and competition indices are included in the model as fixed effects in order to explain residual variability. The data set used in this study came from long-term permanent research plots in even-aged, pure stands both planted and of natural origin. The data base consists of six levels-of-growing stock studies supplemented by initial spacing and other permanent-plot thinning studies for a total of 310 plots, 34,263 trees and 153,854 observations. Regression analysis is the preferred technique used in growth and yield modeling in forestry. We choose the mixed effects models instead of the regression analysis approach because it allows for proper treatment of error terms in a repeated measures analysis framework. Regional growth and yield models exist for ponderosa pine. However, data collection and analysis procedures differ. As a result, comparisons of growth responses that may be due to geographic variation of the species are not possible. Our goal is to present a single distance-independent diameter increment model applicable throughout the geographic range of ponderosa pine in the United States and by using only data from long-term permanent plots on sites capable of the productivity estimated by Meyer [Meyer, W.H., 1938. Yield of Even-Aged Stands of Ponderosa Pine. US Department of Agriculture Technical Bulletin 630].     

Future of the animal health industry at a time of food crisis

It is popular in some quarters to say that there is no food crisis; that there is food aplenty; and that the problem is one of distribution or other over-arching technical difficulty. To the starving, however, there is a food crisis; and it neither speaks well nor bodes well for humanity if we dismiss their plight so glibly. The United Nations has called for a large and rapid increase in food production. Veterinary parasitologists and industry leaders can contribute to the production of healthier livestock and the expansion of aquaculture, but enhanced production and better delivery of plant foods may provide faster relief. Although livestock farming is not the most energy-efficient way of producing food, meat will remain a significant component of the global diet for the foreseeable future. New measures for parasite control will be needed, and we must improve our methods of inventing them. They need not act directly against the parasite. In the distant future lie other threats to the inhabitants of planet Earth, and here we must acknowledge the cogency of the no-food-crisis argument. In the long term, the production of animal foods and animal feeds will be revamped in ways that depend on how (or whether) we solve the energy crisis, the environmental crisis, the increasingly dire regional population crises, and the current world financial crisis. Throughout the 20th century, the animal health industry had to adapt to industrialization and expansive agribusiness. It will have to adapt to even greater changes in the 21st century and beyond.     

Soil invertebrates and the degradation of vanillin,cinnamic acid,and lignins

A range of 8–25% of fed cinnamic 2-[¹⁴C] acid and 9–14% of injected vanillin 5-[¹⁴C] were oxidised to ¹⁴CO₂ at 15 C over 7 and 6 days respectively in an isopod, Oiuscus asellus; a millipede, Pseudopolydesmus serratus; a slug, Deroceras reticulatum; a snail, Oxychilus draparnaldi; and an earthworm, Eisenia foetida. Approximately 2–10% of nonmetabolised and 13–48%, of metabolised vanillin were present in the animal tissues after 6 days. Correspondingly. 1–4% and 22–66% of these materials were found in egesta.A millipede (Oxidus gracilis), O. asellus. D. reticuluttum. O. draparnaldi, and E. foetida were found unable to degrade ring [¹⁴C]-, methoxy [¹⁴C]- and side chain [¹⁴C]-lignin to ¹⁴CO₂ over 10 days, thus providing very strong evidence that these invertebrates are incapable of degrading liginin.