Effects of chromium propionate on growth, carcass traits, and pork quality of growing-finishing pigs

An experiment was conducted to determine the effect of dietary Cr propionate (CrProp) on growth, carcass traits, and pork quality of crossbred finishing gilts. Dietary treatments were 0 or 200 ppb Cr (as CrProp; as-fed basis), and each treatment was replicated four times with five gilts per replicate pen. Gilts were fed diets containing 0.82% lysine from 73 to 80 kg BW and 0.64% lysine from 80 to 115 kg BW. At the end of the trial, carcass and pork quality data were collected from four gilts per replicate. Average daily gain, ADFI, and G:F were not affected (P = 0.76 to 0.96) by CrProp. Before delivery at the abattoir, shrink loss was determined after an 18-h fast (fasting shrink) and after hauling (shipping shrink) pigs for 2.66 h (209.2 km). Fasting, shipping, and overall shrink were not affected (P = 0.14 to 0.39) by CrProp. Carcass length was increased (P = 0.03) in pigs fed CrProp. Loin muscle area, 10th-rib backfat thickness, average backfat thickness, dressing percent, muscle score, fat-free lean, and percent lean were not affected (P = 0.18 to 0.95) by CrProp. Twenty-four-hour loin pH was increased (P = 0.10) in pigs fed CrProp, but 45-min loin and ham pH and 24-h ham pH were not affected (P = 0.39 to 0.83) by CrProp. Subjective (color, marbling, firmness, and wetness) and objective (Commission Internationale de l'Eclairage L*, a*, b*) assessments of the loin muscle (at the 10th-rib interface) were not affected (P = 0.62 to 0.99) by CrProp. Forty-eight-hour drip (P = 0.10) and 21-d purge loss (P = 0.01) were decreased in pigs fed CrProp, but cook and total loss (drip + cook loss) and shear force were not affected (P = 0.35 to 0.53) by CrProp. Plasma cortisol, glucose, and lactate concentrations were not affected (P = 0.28 to 0.97) by CrProp after transportation or during exsanguination. These data indicate that CrProp may improve some aspects of pork quality (loin pH, drip and purge loss) but not growth performance or carcass traits.     

Antioxidant capacity of black currant varies with organ, season, and cultivar

Small berries such as black currant constitute one of the important sources of potential health-promoting phytochemicals because these fruits are rich sources of compounds with high antioxidant properties. In this work, antioxidant capacities of different parts (buds, leaves, fruits) of various black currant cultivars were compared throughout the growing season with the aim to prepare extracts with high antioxidant capacity. Buds (opened, at the end of March) and leaves (in June) had a higher content in phenolics and antioxidants than fully ripened berries (in July) and the best yield (per branch) was obtained with the leaves collected in June due to their higher biomass. The differences observed among the eight cultivars tested were small. Concerning flavonols, quercetin was dominant in all organs and cultivars, myricetin varied widely among the cultivars, and kampferol was very low.     

Immune response to Rhodococcus equi ATCC 33701-secreted proteins in mice and identification of immunogenic recombinant proteins by dot-blotting

Rhodococcus equi remains a significant pathogen, causing severe pneumonia in foals. The development of vaccines and serologic diagnosis could be greatly facilitated by studying the humoral immune response to this equine pathogen. In this study, a crude extract of R. equi ATCC 33701-secreted proteins combined with the Montanide® ISA70 adjuvant was found to be highly immunogenic in mice with the highest titer of 99,000 on day 42 after the first subcutaneous immunization. This immune response was dependent on the quantity of proteins injected and the presence of adjuvant. By dot-blotting, eight recombinant secreted proteins were identified to react strongly with sera from immunized mice. Of these eight proteins, four were detected as immunogenic only when administered in conjunction with adjuvant. This screening strategy led to the identification of promising new candidates for vaccine development.     

The in vitro diagnosis of anthelmintic resistance in cyathostomins

Cyathostomins are the primary parasitic pathogens of equids. For over 40 years, these nematodes have been controlled using broad spectrum anthelmintics. Three classes of anthelmintic are currently available for this use but, unfortunately, resistance to each of these has now been recorded in cyathostomin populations. As part of an optimal strategy to control cyathostomin infections in the field, it will be important to identify drug-resistant worms at as early a stage as possible. This objective needs to be supported by methodologies that will allow the accurate comparison of anthelmintic resistance in different nematode populations. At present, the faecal egg count reduction test is considered the most suitable method for initial screening for anthelmintic resistance in equine nematode populations. However, in its current state, this test lacks sensitivity. It is also costly and time-consuming to perform. Laboratory-based techniques, such as the egg hatch assay, larval development assay, larval migration inhibition assay and the larval feeding inhibition assay offer alternative options for assessing anthelmintic resistance in nematode populations. All of these tests have been investigated for their utility in measuring drug resistance in sheep nematode populations and some have proven useful. The egg hatch assay, larval development assay and larval migration inhibition assay have been investigated for use in measuring levels of drug resistance in equine nematode populations. However, at best, the results obtained thus far indicate that these tests require further refinement.     

Comparing the intra-annual wood formation of three European species (Fagus sylvatica, Quercus petraea and Pinus sylvestris) as related to leaf phenology and non-structural carbohydrate dynamics

Monitoring cambial phenology and intra-annual growth dynamics is a useful approach for characterizing the tree growth response to climate change. However, there have been few reports concerning intra-annual wood formation in lowland temperate forests with high time resolution, especially for the comparison between deciduous and coniferous species. The main objective of this study was to determine how the timing, duration and rate of radial growth change between species as related to leaf phenology and the dynamics of non-structural carbohydrates (NSC) under the same climatic conditions. We studied two deciduous species, Fagus sylvatica L. and Quercus petraea (Matt.) Liebl., and an evergreen conifer, Pinus sylvestris L. During the 2009 growing season, we weekly monitored (i) the stem radial increment using dendrometers, (ii) the xylem growth using microcoring and (iii) the leaf phenology from direct observations of the tree crowns. The NSC content was also measured in the eight last rings of the stem cores in April, June and August 2009. The leaf phenology, NSC storage and intra-annual growth were clearly different between species, highlighting their contrasting carbon allocation. Beech growth began just after budburst, with a maximal growth rate when the leaves were mature and variations in the NSC content were low. Thus, beech radial growth seemed highly dependent on leaf photosynthesis. For oak, earlywood quickly developed before budburst, which probably led to the starch decrease quantified in the stem from April to June. For pine, growth began before the needles unfolding and the lack of NSC decrease during the growing season suggested that the substrates for radial growth were new assimilates of the needles from the previous year. Only for oak, the pattern determined from the intra-annual growth measured using microcoring differed from the pattern determined from dendrometer data. For all species, the ring width was significantly influenced by growth duration and not by growth rate, which differs from previous studies. The observed between-species difference at the intra-annual scale is key information for anticipating suitability of future species in temperate forests.