Effect of feed restriction on dairy cow milk production: a review

In the dairy cow, negative energy balance affects milk yield and composition as well as animal health. Studying the effects of negative energy balance on dairy cow milk production is thus essential. Feed restriction (FR) experiments attempting to reproduce negative energy balance by reducing the quantity or quality of the diet were conducted in order to better describe the animal physiology changes. The study of FR is also of interest since with climate change issues, cows may be increasingly faced with periods of drought leading to a shortage of forages. The aim of this article is to review the effects of FR during lactation in dairy cows to obtain a better understanding of metabolism changes and how it affects mammary gland activity and milk production and composition. A total of 41 papers studying FR in lactating cows were used to investigate physiological changes induced by these protocols. FR protocols affect the entire animal metabolism as indicated by changes in blood metabolites such as a decrease in glucose concentration and an increase in non-esterified fatty acid or β-hydroxybutyrate concentrations; hormonal regulations such as a decrease in insulin and insulin-like growth factor I or an increase in growth hormone concentrations. These variations indicated a mobilization of body reserve in most studies. FR also affects mammary gland activity through changes in gene expression and could affect mammary cell turnover through cell apoptosis, cell proliferation, and exfoliation of mammary epithelial cells into milk. Because of modifications of the mammary gland and general metabolism, FR decreases milk production and can affect milk composition with decreased lactose and protein concentrations and increased fat concentration. These effects, however, can vary widely depending on the type of restriction, its duration and intensity, or the stage of lactation in which it takes place. Finally, to avoid yield loss and metabolic disorders, it is important to identify reliable biomarkers to monitor energy balance.     

Gene discovery in Eimeria tenella by immunoscreening cDNA expression libraries of sporozoites and schizonts with chicken intestinal antibodies

Specific antibodies were produced ex vivo from intestinal culture of Eimeria tenella infected chickens. The specificity of these intestinal antibodies was tested against different parasite stages. These antibodies were used to immunoscreen first generation schizont and sporozoite cDNA libraries permitting the identification of new E. tenella antigens. We obtained a total of 119 cDNA clones which were subjected to sequence analysis. The sequences coding for the proteins inducing local immune responses were compared with nucleotide or protein databases and with expressed sequence tags (ESTs) databases. We identified new Eimeria genes coding for heat shock proteins, a ribosomal protein, a pyruvate kinase and a pyridoxine kinase. Specific features of other sequences are discussed.     

Monitoring Particulate Matter Concentrations with Passive Samplers: Application to the Greater Thessaloniki Area

Modern European cities are characterized by high particulate matter (PM) concentrations. Unfortunately, the number of stations monitoring air pollution, especially PM, is never sufficient for the overall representation of the problem. In the present work, an inexpensive outdoor passive sampler (based on an indoor passive sampler) was developed and assembled in an effort to provide the means to extend current PM monitoring networks. The uncertainty of the sampler was tested in vitro and in vivo. Twenty such outdoor passive samplers were assembled and installed at specific locations in the Greater Thessaloniki Area and measurements of PM were carried out. The results were in good agreement with the official monitoring stations. In addition, they revealed the aggravated air quality in the center of the city and in the west suburbs.     

Authentication of natural vanilla flavorings: isotopic characterization using degradation of vanillin into guaiacol

The isotopic investigation of vanillin has been extended to the new sources of natural precursors of vanillin recently introduced with a view of obtaining natural vanillin by biotechnological processes. To check the consistency of the isotopic composition of vanillin with that of the corresponding aromatic fragment, a selective degradation reaction into guaiacol was carried out. The reaction was shown to proceed without significant isotopic fractionation at the sites of interest, and an optimized procedure was defined from the results of an experimental design involving the quantity of reagent and the temperature and duration of the experiment. Guaiacol, which can be easily obtained in a reasonable time, is an interesting isotopic probe for carbon- and oxygen-isotope ratio mass spectrometry (IRMS) determinations. It provides (13)C information specific to the aromatic fragment and, combined with delta(13)C values measured on vanillin itself, it improves the authentication potential of carbon-IRMS. Thus, the natural status of ferulic acid may be characterized by significant (13)C depletion at the formyl site. Similarly, the oxygen-18 content of guaiacol is a better authentication tool than delta(18)O of vanillin because it does not suffer the drawback of being altered by chemical exchange of the sp(2) oxygen atom with water in industrial or laboratory procedures. Although collaborative studies are still necessary to improve the interlaboratory reproducibility of the delta(18)O parameters, consistent results can be obtained in an intralaboratory context. It is shown in particular that chemical oxidation of ferulic acid is characterized by a relative enrichment of the aromatic moiety of vanillin.     

Antifungal effects of iron sulfate on grapevine fungal pathogens

The present study aimed to determine the most efficient experimental conditions of iron sulfate use leading to optimal inhibition in the development of fungal pathogens. Assays have been focused on fungal species inducing severe grapevine diseases. FeSO₄ directly inhibited the in vitro mycelial growth of Botrytis cinerea, Eutypa lata, Phaeomoniella chlamydospora, Phaeoacremonium aleophilum, Diplodia seriata, and Neofusicoccum parvum with variable efficiency in the range of 0.5–10 mM. The development was always completely inhibited at 20 mM. This inhibitory effect was greatly increased at acidic pH values. The anionic moiety of the molecule was of importance since bromide, chloride and sulfate were highly active, whereas acetate and oxalate showed a small effect. Electron microscope observations on E. lata and B. cinerea showed that a treatment with FeSO₄ induced dramatic changes in the hyphal organization leading to cell death. No toxicity was observed on grapevine leaves following repeated FeSO₄ sprays in the antifungal concentration range. Therefore, FeSO₄ may be proposed to effectively replace the long-term pollutant use of CuSO₄ as an antifungal agent, with the additional advantage of iron being an important plant micronutrient.     

Volatile constituents of Semnostachya menglaensis Tsui

Semnostachya menglaensis Tsui (Acanthaceae) is a rare plant indigenous to Mengla in the tropical rainforest of the Xishuangbanna prefecture in the south of Yunnan province, People's Republic of China. When the leaves are crushed, a characteristic smell of basmati rice or pandan leaves develops. Their hexane extract, prepared from a specimen growing in a greenhouse of the botanical garden of the Kunming Institute of Botany, contains 1-(3,4,5,6-tetrahydro-2-pyridyl)-1-propanone (41.2%) and 1-(1,4,5,6-tetrahydro-2-pyridyl)-1-propanone (37.5%) which constitute the main part of the volatile compounds. Minor components are 1-(3,4,5,6-tetrahydro-2-pyridyl)-1-ethanone (4.9%), 1-(1,4,5,6-tetrahydro-2-pyridyl)-1-ethanone (4.8%), 1-(2-piperidyl)-1-propanone (5.2%), 1-octen-3-ol (3.2%), 1-octen-3-one (1.9%), and 3-octanol and 1-(2-pyridyl)-1-propanone in trace amounts.     

Characterization using Raman microspectroscopy of arabinoxylans in the walls of different cell types during the development of wheat endosperm

The time course and pattern of arabinoxylan deposition in the wheat (Triticum aestivum) endosperm during grain development were studied using Raman spectroscopy. The presence of arabinoxylans (AX) is detected at the beginning of grain filling. At this stage, AX appear more substituted than at the later stages. Feruloylation of AX increases during the grain-filling stage, especially in the case of the aleurone layer. Whatever the stage of grain development, four populations of cells could be defined according to Raman arabinoxylan signatures. In the walls of the aleurone cells, AX appeared to be little substituted and highly esterified with phenolic acids. In the walls of prismatic cells, AX were found to be highly substituted and poorly esterified. Apart from aleurone and prismatic cells, the substitution degree of AX in endosperm was in the same range. Cells in the crease region were distinguished from cells in the starchy endosperm by their lower amount of esterified phenolic compounds.     

Comparison of flow cytometry and immunofluorescence microscopy for the detection of Giardia duodenalis in bovine fecal samples.

The performance of flow cytometry (FC) was compared with immunofluorescence microscopy (IM) for detection of Giardia duodenalis in bovine feces. Samples from 36 adult dairy cows and 208 dairy calves were collected. Flow cytometry test characteristics were calculated using continuous, ordinal, and dichotomized results. Spearman correlation coefficients comparing the results of the 2 tests were 0.47 and 0.68 for cows and calves, respectively. Using IM as indicative of presence or absence of G. duodenalis cysts in each sample, likelihood ratios of FC results with 0, 1, and > or = 2 gated events indicated that samples with 1 gated event were likely to be positive in the cows but not in the calves. Immunofluorescence microscopy detected G. duodenalis in 69.7% and 48.1% of cows and calves, respectively. When dichotomizing the FC results at a cut-off point of 1 or 2 gated events, 46.3% and 19.9% of the cow and 51.9% and 35.1% of the calf samples, respectively, were classified as G. duodenalis-positive. Relative to IM, the sensitivity in the cows was 0.59 and 0.28, respectively, and 0.76 and 0.64, respectively, in the calves. At a cut-off point of 1, 65.7% and 73.1% of the cow and calf samples, respectively, were correctly classified in FC, and at a cut-off point of 2, 49.3% and 78.4% were correctly classified in the cows and calves, respectively. Flow cytometry was less sensitive than IM. Possible reasons and research needed to improve FC for G. duodenalis detection are discussed.     

Production and isolation of azaspiracid-1 and -2 from Azadinium spinosum culture in pilot scale photobioreactors

Azaspiracid (AZA) poisoning has been reported following consumption of contaminated shellfish, and is of human health concern. Hence, it is important to have sustainable amounts of the causative toxins available for toxicological studies and for instrument calibration in monitoring programs, without having to rely on natural toxin events. Continuous pilot scale culturing was carried out to evaluate the feasibility of AZA production using Azadinium spinosum cultures. Algae were harvested using tangential flow filtration or continuous centrifugation. AZAs were extracted using solid phase extraction (SPE) procedures, and subsequently purified. When coupling two stirred photobioreactors in series, cell concentrations reached 190,000 and 210,000 cell · mL(-1) at steady state in bioreactors 1 and 2, respectively. The AZA cell quota decreased as the dilution rate increased from 0.15 to 0.3 day(-1), with optimum toxin production at 0.25 day(-1). After optimization, SPE procedures allowed for the recovery of 79 ± 9% of AZAs. The preparative isolation procedure previously developed for shellfish was optimized for algal extracts, such that only four steps were necessary to obtain purified AZA1 and -2. A purification efficiency of more than 70% was achieved, and isolation from 1200 L of culture yielded 9.3 mg of AZA1 and 2.2 mg of AZA2 of >95% purity. This work demonstrated the feasibility of sustainably producing AZA1 and -2 from A. spinosum cultures.