Endocrine effects of GnRH agonist application to early pregnant gilts

The hypothesis of the present study was that a GnRH agonist application at early pregnancy would alter the pattern of the key reproductive hormones LH and FSH, and subsequently that of estradiol (E2) and especially progesterone (P4), and improve the conditions for embryo survival in early pregnant gilts. Therefore, the endocrine effects of a GnRH agonist (GnRHa) application to gilts (n=11 GnRHa treated, n=9 saline Controls) were studied in blood samples from the Vena cava caudalis. GnRHa injected on Day 12 after insemination induced elevated (P<0.01) LH and FSH levels for at least 180 min. However, subsequent LH concentrations were not altered up to Day 21 of pregnancy. LH pulse number, estimated in 6-h period samples on Days 13, 15 and 17, was not influenced by treatment and pregnancy. LH pulse amplitude was decreased (P<0.05) on Days 13 to 17 in pregnant gilts of both groups, but not in nonpregnant animals. In pregnant GnRHa-treated gilts, the basal LH level was elevated compared with the Controls (P<0.01). Additionally, differences (P<0.05) in basal LH were present between the pregnant and nonpregnant animals. The P4 and E2 secretion pattern was not affected by GnRHa. P4 concentrations increased (P<0.01) from Day 10 to Day 14 regardless of the treatment. P4 revealed a pulse-like pattern, but without a definite relation to the LH pulse characteristics. Also, pregnancy rate (73 vs. 67%) and the number of fetuses (12.8 ± 2.3 vs. 11.6 ± 2.3) were unaffected in the treated and Control gilts, respectively. The present study did not confirm the initial hypothesis that a GnRHa-mediated LH effect could alter ovarian steroid secretion and favorably support early embryo development and pregnancy outcome.     

A comparative study of clinical manifestations,haematological and serological responses after experimental infection with Anaplasma phagocytophilum in two Norwegian sheep breeds

Background

It has been questioned if the old native Norwegian sheep breed, Old Norse Sheep (also called Norwegian Feral Sheep), normally distributed on coastal areas where ticks are abundant, is more protected against tick-borne infections than other Norwegian breeds due to a continuously high selection pressure on pasture. The aim of the present study was to test this hypothesis in an experimental infection study.

Methods

Five-months-old lambs of two Norwegian sheep breeds, Norwegian White (NW) sheep and Old Norse (ON) sheep, were experimentally infected with a 16S rRNA genetic variant of Anaplasma phagocytophilum (similar to GenBank accession number {"type":"entrez-nucleotide","attrs":{"text":"M73220","term_id":"148293"}}M73220). The experiment was repeated for two subsequent years, 2008 and 2009, with the use of 16 lambs of each breed annually. Ten lambs of each breed were inoculated intravenously each year with 0.4 ml A. phagocytophilum-infected blood containing approximately 0.5 × 10⁶ infected neutrophils/ml. Six lambs of each breed were used as uninfected controls. Half of the primary inoculated lambs in each breed were re-challenged with the same infectious dose at nine (2008) and twelve (2009) weeks after the first challenge. The clinical, haematological and serological responses to A. phagocytophilum infection were compared in the two sheep breeds.

Results

The present study indicates a difference in fever response and infection rate between breeds of Norwegian sheep after experimental infection with A. phagocytophilum.

Conclusion

Although clinical response seems to be less in ON-lambs compared to NW-lambs, further studies including more animals are needed to evaluate if the ON-breed is more protected against tick-borne infections than other Norwegian breeds.     

Animal health in the 21st century-a global challenge

On the occasion of the centenary of the Friedrich-Loeffler-Institut, a conference entitled 'Animal Health in the 21st Century' was held in Greifswald, Germany, on 11-13 October 2010 to discuss current and future challenges regarding the global situation regarding infectious animal diseases and zoonoses, animal breeding, animal nutrition and animal welfare. Particular attention was paid to the impact of recent developments and anticipated future trends on livestock production.     

Biochemical characteristics of solid fractions from animal slurry separation and their effects on C and N mineralisation in soil

Solid fractions from separated animal slurry can be used as organic fertilisers on agricultural land. Solid fractions contain variable amounts of inorganic and organic N, so it is important to synchronise their application in the field with crop demand to ensure N availability in the growing season. This study quantified C and N mineralisation for a wide range of solid fractions from slurry separation applied to soil and examined potential correlations between chemical and biochemical characteristics of solid fractions and their C and N turnover. The solid fractions were mixed with soil and incubated at 14°C for 120 days, during which CO₂ evolution and inorganic N content of the solid fractions were determined. A two-parameter exponential function fitted to the individual solid fraction C mineralisation patterns explained 98% of the data variation, while a three-parameter Monod-type equation fitted to the net N mineralisation patterns explained 89% of the variation. Between 5% and 45% of initially added C was mineralised within the incubation period, with the largest proportion tending to be mineralised from simple mechanically separated solid fractions (MEC). Nitrogen was initially immobilised by the majority of solid fractions. Solid fractions from decanter centrifuged, anaerobically digested slurry (DEC) and chemically pre-treated and separated slurry (KEM) began to re-mineralise N after 20?C40 days, whereas N was continuously immobilised from MEC solid fractions. The carbon mineralisation rate constant was correlated with the C content in the neutral detergent soluble (NDS), hemicellulose and cellulose fractions and the N content in NDS. Net nitrogen mineralisation was correlated with the C/Norg ratio of solid fractions, the N content of NDS and the C content of hemicellulose and cellulose.     

The decomposition of turfgrass clippings is fast at high air humidity and moderate temperature

Abstract

In grassland areas where herbage production has no economic value, the cut grass is often left on the sward surface where its decomposition is influenced by weather conditions. Although the influence of temperature and humidity on decomposition has been investigated under controlled lab conditions, experimentation has generally been under ideal moisture conditions that have not tested the combinations of climatic limitations that might occur in the field. The decomposition of mown turfgrass clippings deposited at different times of vegetation period was studied in situ using nylon bags during the first 8 weeks after deposition to investigate the effect of weather conditions (the air temperature, relative humidity, precipitation) on decomposition. Decomposition is the highest in the case of high air humidity and temperature of 10°C. Limiting factors for decomposition at temperatures above 10°C is the air humidity and below 10°C the air temperature. The general tendency was that the rate of decomposition increased with increasing air temperature up to 10°C, but with further increases of air temperature the decomposition rate slowed down. Relative air humidity had a variable impact (at the beginning of the decomposition process (weeks 1–2) the influence was negative, during weeks 3–8 of the decomposition process the effect was positive), and hence had no generalized relationship with decomposition over the studied decomposition period (weeks 1–8). The most significant influence of weather conditions on the decomposition rate was recorded directly after cutting. If the cutting was done during hot weather conditions, the material was drying fast and therefore decomposed slowly. Our results indicate that for fast decomposition of clippings it is important to maintain the freshness of material. Lower decomposition rates occurred during conditions of hot and dry weather, and also cooler (temperature near to 0°C) weather, and can be compensated as soon as favourable weather arrives.     

Effects of drought and canopy ozone exposure on antioxidants in fine roots of mature European beech (Fagus sylvatica)

We quantified ascorbate, glutathione and alpha-tocopherol in fine roots of mature Fagus sylvatica L. under free-air canopy ozone (O(3)) exposure (twice ambient O(3) concentration, 2x[O(3)]) during two growing seasons that differed in the extent of summer drought (exceptional drought year 2003, average year 2004). This design allowed us to test whether O(3) exposure or drought, or both, affected root antioxidants during the growing season. In both years, root ascorbate and alpha-tocopherol showed a similar relationship with volumetric soil water content (SWC): ascorbate concentrations on a root dry mass basis increased from about 6 to 12 micromol g(-1) when SWC dropped from 25 to 20%, and a-tocopherol increased from 100 to 150 nmol g(-1) at SWC values below 20%. Root glutathione showed no relationship with SWC or differences between the dry and the average year, but it was significantly and consistently diminished by 2x[O(3)]. Our results were inconclusive as to whether shoot-root translocation of glutathione or glutathione production in the roots was diminished. Phloem glutathione concentrations in the canopy remained constant, but reduced transport velocity in the phloem and, as a consequence, reduced mass flow of glutathione cannot be ruled out.     

Prospects for a novel vaccine against tuberculosis

The development of a new and improved vaccine against tuberculosis has in the last 10 years been accelerated tremendously from the completed Mycobacterium tuberculosis genome and the progress in molecular biology. This has resulted in the identification of a large number of antigens with potential in tuberculosis vaccines. The next phase of this work has now started--putting the most relevant molecules back together as fusion molecules and cocktails. This requires carefully monitoring of aspects as immunodominance, recognition in different populations as well as the influence of different adjuvants and delivery systems. The most advanced of these vaccines such as the fusion between ESAT6 and Ag85B have been evaluated in a range of animal models including non-human primates and are now entering into clinical trials. For these vaccines to be successfully implemented in future vaccination programmes it is necessary to understand the immunological background for the failure of BCG and optimize the vaccines for their ability to boost the immuno-response primed by BCG.     

IGF-I- and EGF-dependent DNA synthesis of porcine myoblasts is influenced by the dietary isoflavones genistein and daidzein

Soy-derived isoflavones have been reported to be specific inhibitors of protein tyrosine kinases like the type 1 insulin-like growth factor receptor (IGF-1R) and the epidermal growth factor receptor (EGFR). This study was conducted to investigate, whether IGF-I and EGF stimulate porcine myoblast growth and whether the responses are influenced by isoflavones. Satellite cell-born myoblasts derived from the semimembranosus muscle of newborn piglets were treated for 26h with IGF-I or EGF alone and in combination with genistein or daidzein. The DNA amount was measured and DNA synthesis was recorded as 6 h-[(3)H]thymidine incorporation during exponential growth in serum-free basal medium. IGF-I and EGF synergistically stimulated DNA synthesis of porcine myoblast with EGF causing a greater response. Genistein (100mumol/l) effectively reduced the growth factor-mediated DNA synthesis, which was associated with an inhibition of growth factor receptor protein expression. In response to daidzein no reduction in growth factor-mediated DNA synthesis was found. Daidzein (1; 10mumol/l) combined with IGF-I caused even a slight increase in DNA amount compared with the untreated control. The expression of the IGF-1R precursor protein was reduced with 10 and 100mumol/l daidzein, whereas the EGFR expression remained unchanged with daidzein. The results suggest that dietary isoflavones may interact with growth factor-induced stimulation of pig skeletal muscle growth.