Diet change from a system combining total mixed ration and pasture to confinement system (total mixed ration) on milk production and composition,blood biochemistry and behavior of dairy cows

This study aimed to determine if a diet change from a mixed system to a confinement system affects the milk production and composition, behavior and blood biochemistry of dairy cows. Cows were assigned randomly to one of the two treatments: cows fed with TMR (total‐mixed‐ration) (confined) throughout the period group fed TMR (GTMR, n = 15) and cows that changed their diet from pasture plus TMR to exclusive TMR at 70 ± 14 DIM (GCHD, n = 15). GTMR cows produced more milk and greater lactose and protein yield before the change of diet than GCHD cows (p ≤ .01), but these differences disappeared after the change. GCHD cows decreased the frequency of rumination and lying from before to after the change (p ≤ .03), but in GTMR cows no changes were observed. After diet change, GCHD cows had lower frequency of rumination and lying than GTMR cows (p ≤ .02). Before the change, GCHD cows had greater NEFA (non esterified fatty acids) concentrations than GTMR cows (p = .002). Abrupt change from a mixed system to a confined system was favorable on blood biochemical and milk variables of dairy cows. However, in relation to behavior, the cows expressed difficulties to adapt quickly to the abrupt change of system.     

Glutenin and gliadin contents of flour derived from wheat infested with different aphid species

Aphid feeding in cereals results in both quantitative and qualitative yield losses; moreover aphid-transmitted viruses are responsible for other quantitative and qualitative damage so that direct or indirect effects of aphid infection are always of interest. At the beginning of stem elongation, wheat plants were caged regardless of the presence or absence of indigenous cereal aphids. Half of the caged plants were artificially infected with Diuraphis noxia. The number of D noxia and Rhopalosiphum padi individuals on plants destined for flour preparation was approximately 150 aphids per tiller at peak population. The number of Sitobion avenae individuals was ca 25 aphids per tiller. Bread-making quality of wheat flour is determined primarily by the protein content, the gluten proteins (gliadins, glutenins) being the prime factors. The absolute amounts and/or the relative proportion of gliadins and glutenins are very important in dough making and in determining baking quality. Flour from grains originating from plants infected naturally with cereal aphids indigenous to Hungary, and flour infected artificially with D noxia, were analysed for glutenin and gliadin content using size exclusion HPLC. It was found that aphid infection had a significant effect on the gliadin/glutenin ratio, which was significantly lower in wheat flour prepared from aphid-infected plants than in that from uninfected control. The most significant decrease in gliadin/glutenin ratio was caused by D noxia infection, followed by R padi and then S avenae. As the gliadin/glutenin ratio was significantly lower in flour made from aphid-infected wheat seeds, it can be supposed that aphid feeding results in decreased bread making quality of wheat flour.     

Control of spawning activity in female Nile tilapia (Oreochromis niloticus) (L.) by temperature manipulation

The aim of this study was to maximize the spawning of Oreochromis niloticus females in a specific time period. Females were divided randomly into control and treatment groups. In the treatment groups, females were kept for one week at 28±0.5 °C, after which they were exposed to a reduced water temperature of 22±0.5 °C for 7, 14 and 28 days. Thereafter, the temperature was restored to 28 °C. Females in the control groups were kept continuously at a water temperature of 28 °C. All females were checked daily for signs of spawning for the duration of the experiments and were manually stripped if ready to spawn. The following parameters were calculated for period of 3 and 7 days following a 28 °C temperature restoration: spawning rate, number of eggs per female, weight of female, relative fecundity (eggs g⁻¹ body weight) and the percentage of hatched and swim-up fry. The highest spawning rate of 39.5% was obtained in the 14-day trial over a period of 7 days, while the corresponding value in the control was 12.5%. The percentages of hatched and swim-up fry in the 14- and 28-day trials, however, were significantly higher in the controls than in the corresponding treatment groups.     

Groundwater Pollution in a Karstic Region (NE Yucatan): Baseline Nutrient Content and Flux to Coastal Ecosystems

The quality of groundwater is threatened in karstic regions with very high population growth, such as the eastern coast of Yucatan. As polluted groundwater flows towards the ocean, coastal ecosystems and coral reefs may also be affected. Pollution and the interaction between the coastal aquifer and the reef lagoon were assessed at a developing area (Puerto Morelos, NE Yucatan Peninsula) within the Mesoamerican Coral Reef System. Coastal environments along the land?Csea gradient (wells, mangroves, beaches, submarine springs, the reef lagoon, and the open sea) were sampled. Silicate and salinity were used as tracers of groundwater and seawater, respectively. Their patterns evidence water flow and mixing among these coastal environments. High nitrate concentrations (268.6 ??M) and coliform bacteria densities indicate groundwater pollution in most of the wells sampled and also in mangroves, beaches, and submarine springs. Phosphorous content peaks (14.2 ??M) in mangroves, where it is likely released due to reducing conditions in the sediments. Nitrogen flux toward the lagoon reef through groundwater discharge is estimated at 2.4 ton N km^?1 year^?1 and phosphorous at 75 to 217 kg P km^?1 year^?1. These results provide evidence of the need for more detailed groundwater studies and for the integrated management of aquifers and coastal ecosystems in karstic regions.     

Predicting the invasion risk by the alien bee-hawking Yellow-legged hornet Vespa velutina nigrithorax across Europe and other continents with niche models

Vespa velutina nigrithorax, an Asian bee-hawking hornet, has been unintentionally introduced in south-western France before 2004 and is currently widely spreading across the country. Its arrival in northern Spain was reported in 2010. The potential invasion risk of the species is assessed using climatic suitability models. We used eight different modelling techniques within an ensemble forecast framework to show that the invasion success in south-western France could have been predicted using data from the native Asian range of the species, while we further used data from both the native and invaded ranges (including a recently established population in Korea) to better predict its potential invasion range across all continents. Results are discussed in terms of the interest of ecological niche modelling for invasion biology, realised niche of the invasive wasp, potential threats to native entomofauna and economic impacts of this new predator. A particular attention is paid to beekeeping activities that are nowadays already threatened by a wide panel of adversary factors.     

Fast virtual histology using X-ray in-line phase tomography: application to the 3D anatomy of maize developing seeds

Background

Despite increasing demand, imaging the internal structure of plant organs or tissues without the use of transgenic lines expressing fluorescent proteins remains a challenge. Techniques such as magnetic resonance imaging, optical projection tomography or X-ray absorption tomography have been used with various success, depending on the size and physical properties of the biological material.

Results

X-ray in-line phase tomography was applied for the imaging of internal structures of maize seeds at early stages of development, when the cells are metabolically fully active and water is the main cell content. This 3D imaging technique with histology-like spatial resolution is demonstrated to reveal the anatomy of seed compartments with unequalled contrast by comparison with X-ray absorption tomography. An associated image processing pipeline allowed to quantitatively segment in 3D the four compartments of the seed (embryo, endosperm, nucellus and pericarp) from 7 to 21 days after pollination.

Conclusion

This work constitutes an innovative quantitative use of X-ray in-line phase tomography as a non-destructive fast method to perform virtual histology and extends the developmental stages accessible by this technique which had previously been applied in seed biology to more mature samples.

     

Endometrial gene expression in primiparous dairy cows at the end of the voluntary waiting period is affected by nutrition: Total mixed ration vs increasing levels of herbage allowance

The study postulated that differential nutritional management during the early lactation period would be reflected in endometrial expression of genes related to embryo growth at the end of the voluntary waiting period. Thus, the effect of the combined use of total mixed ration (TMR) and grazing under different herbage allowances during the first 75 days post‐partum (DPP) on endometrial gene expression was evaluated in primiparous dairy cows. Cows were blocked by body weight, age and body condition score and randomly assigned to three grazing treatments: high (HA, 30 kg DM per cow per day), medium (MA, 15 kg DM per cow per day) and low (LA, 7.5 kg DM per cow per day) herbage allowance (mixed pasture, 2,600 kg DM per ha) plus 8 kg DM of supplement or TMR (55% forage, 45% concentrate) fed ad libitum (TMR) from calving to 75 DPP. At 57 DPP, cows were synchronized for oestrus (day 0, 68 DPP) and at day 7, endometrial biopsies were obtained. The nutritional treatment did not affect insulin, IGF‐1 and leptin concentrations on days 0, 4 or 7. Expression of IGF1, IGFBP3, IGFBP4, ADIPOR1 and ADIPOR2 mRNA was significantly affected by the nutritional treatment. Endometrial IGF1 and IGFBP4 mRNA were twofold greater in TMR and HA than MA and LA cows. Expression of IGFBP3 and ADIPOR1 mRNAs was greater in TMR and HA than MA cows, but did not differ from LA cows. All groups had greater expression of ADIPOR2 mRNA than MA cows. This study provided solid evidence of the importance of nutritional management during early lactation on uterine environment at the end of the voluntary waiting period. The greater expression of genes related to embryo growth and uterine function (IGF system, progesterone and adiponectin receptors) in cows fed diets maximizing energy intake suggests a favourable environment for embryonic growth, which may explain the improved reproductive performance of cows in good energy balance.     

Plant regulation of microbial enzyme production in situ

Soil extracellular enzymes regulate the rate at which complex organic forms of nitrogen (N) become bio-available. Much research has focused on the limitations to heterotrophic enzyme production via lab incubations, but little has been done to understand the limitations to enzyme production in situ. We created root and symbiotic mycelia exclusion treatments using mesh in-growth bags in the field to isolate the effect of roots and other portions of the microbial community on enzyme production. When fertilized with complex protein N we found increases in N-degrading enzyme concentrations only when root in-growth was allowed. No response was observed when complex N was added to root-free treatments. Expanding on economic rules of microbial element limitation theory developed from lab incubation data, we suggest this is due to active transport of labile carbon (C) from roots to associated microbial communities in root bags. Roots alleviate C limitation of microbial enzyme synthesis, representing a tradeoff between plants and microbes–plant C for microbially-derived N.