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Two experiments were undertaken to evaluate the effect on milk and cheese fatty acid composition of feeding different fresh forages to dairy sheep both in winter (experiment 1, growing stage of the forages, early lactating ewes) and in spring (experiment 2, reproduction stage of the forages, midlactating ewes). Four forage species were compared: annual ryegrass (RY, Lolium rigidum Gaudin), sulla (SU, Hedysarum coronarium L.), burr medic (BM, Medicago polymorpha L.), and a daisy forb (CH, Chrysanthemum coronarium L.). The forages were cut twice daily and offered ad libitum to 4 replicate groups of Sarda dairy sheep (groups RY, SU, BM, and CH). The CH forage was particularly rich in linoleic acid in both periods, whereas BM and SU forages were rich in linolenic acid in winter and spring, respectively. Milk fatty acid composition was affected by the forage in both experiments. Milk conjugated linoleic acid and vaccenic acid contents were higher in CH and BM groups (winter) and CH group (spring) than in the other groups. No differences were observed when comparing fatty acid profile between milk, 1-d-old cheeses, and 60-d-old cheeses within experimental groups, suggesting that the fatty acid recovery rates during cheese making and ripening were not affected by the feeding regimens. After stepwise discriminant analyses of the pooled data, the milks and cheeses sourced in the different feeding regimens differed among them. Based on these results, we conclude that it is possible to manipulate the fatty acid profile of sheep dairy produce to maximize the content of beneficial fatty acids by the use of appropriate fresh forage-based regimens.

The present study used a sheep model of intrauterine growth restriction, combining maternal undernutrition and twinning, to determine possible markers of early damage to the fetal kidney. The occurrence of early deviations in fetal hemodynamics which may be indicative of changes in blood perfusion was assessed by Doppler ultrasonography. A total of 24 sheep divided in two groups were fed with the same standard grain-based diet but fulfilling either their daily maintenance requirements for pregnancy (control group; n=12, six singleton and six twin pregnancies) or only the 50% of such quantity (food-restricted group; n=12; four singleton and eight twin pregnancies). All the fetuses were assessed by both B-mode and Doppler ultrasonography at Day 115 of pregnancy. Fetal blood supply was affected by maternal undernutrition, although there were still no evidences of brain-sparing excepting in fetuses at greatest challenge (twins in underfed pregnancies). However, there were early changes in the blood supply to the kidneys of underfed fetuses and underfed twins evidenced decreases in kidney size.

Abstract The majority of ruminants in the world are grazers. Thus, the proper supplementation of energy and nutrients to grazing ruminants is essential to ensure their level of production meets their genetic potential (i.e., precision feeding), leading to sustainable livestock production scenarios. However, an adequate provision of supplements depends on the accurate determination of the nutritive value of the forage, which is a function of how much nutrients can be extracted from the forage by the ruminant animal and an accurate assessment of energy and nutrient requirements by the grazing animal. Nutritive indices have been developed to provide nutritional information on forage quality and animal intake, but they are simplifications of a much more complicated system. Nutrition models have tackled these aspects from a more comprehensive viewpoint, but there still room for holistic concepts to fuse critical elements (soil, climate, forage, and animal) together in developing more mechanistic tools. For instance, the determination of forage consumption by grazing ruminants is substandard at least, though it has been evolving at a somewhat slower pace than anticipated. Additional areas that need improvements in the supply side are accounting for substitution rates of concentrate feeds (protein and energy) and forage fiber level, how grazing on grasses-legume mixtures impact forage consumption and long-term pasture maintenance, assessment of quantity and quality of forages, and animal selectivity. On the requirement side, needed improvements include an adequate assessment of energy expenditure for physical activity, the impact of global warming condition on energy and nutrient requirements and grazing activities, and nutrient requirements for efficient animals. Therefore, integrated agricultural models must represent ruminants as an additional trophic level, so the synchronization and flow of nutrients are used to predict forage availability, and animal feed requirement for drought-prone regions and different management strategies with and without ruminants can be evaluated.

The majority of ruminants in the world are grazers. Thus, the proper supplementation of energy and nutrients to grazing ruminants is essential to ensure their level of production meets their genetic potential (i.e., precision feeding), leading to sustainable livestock production scenarios. However, an adequate provision of supplements depends on the accurate determination of the nutritive value of the forage, which is a function of how much nutrients can be extracted from the forage by the ruminant animal and an accurate assessment of energy and nutrient requirements by the grazing animal. Nutritive indices have been developed to provide nutritional information on forage quality and animal intake, but they are simplifications of a much more complicated system. Nutrition models have tackled these aspects from a more comprehensive viewpoint, but there still room for holistic concepts to fuse critical elements (soil, climate, forage, and animal) together in developing more mechanistic tools. For instance, the determination of forage consumption by grazing ruminants is substandard at least, though it has been evolving at a somewhat slower pace than anticipated. Additional areas that need improvements in the supply side are accounting for substitution rates of concentrate feeds (protein and energy) and forage fiber level, how grazing on grasses-legume mixtures impact forage consumption and long-term pasture maintenance, assessment of quantity and quality of forages, and animal selectivity. On the requirement side, needed improvements include an adequate assessment of energy expenditure for physical activity, the impact of global warming condition on energy and nutrient requirements and grazing activities, and nutrient requirements for efficient animals. Therefore, integrated agricultural models must represent ruminants as an additional trophic level, so the synchronization and flow of nutrients are used to predict forage availability, and animal feed requirement for drought-prone regions and different management strategies with and without ruminants can be evaluated.

A study was undertaken to assess the impact of the timing of grazing on rumen and plasma metabolites and some metabolic hormones in lactating dairy sheep allocated to an Italian ryegrass (Lolium multiflorum Lam) pasture in spring for 4 h/d. Twenty-four mid lactation Sarda ewes stratified for milk yield, body weight, and body condition score, were divided into four homogeneous groups randomly allocated to the treatments (2 replicate groups per treatment). Treatments were morning (AM, from 08:00 to 12:00) and afternoon pasture allocation (PM, from 15:30 to 19:30). Samples of rumen liquor (day 39) and blood plasma (days 17 and 34 of the experimental period) were collected before and after the grazing sessions. Moreover, on days 11 and 35, grazing time was assessed by direct observation and herbage intake measured by the double weighing procedure. Grazing time was longer in PM than AM ewes (P < 0.001) but herbage intake was undifferentiated between groups. The intake of water-soluble carbohydrates at pasture was higher in PM than AM ewes (P < 0.05). The post-grazing propionic and butyric acid concentration, as measured on day 39, were higher in PM than AM ewes (P < 0.05). The basal level of glucose on day 34 and insulin (on both sampling days) were higher in PM than AM (P < 0.05). The opposite trend was detected for non-esterified fatty acids (P < 0.05, day 34) and urea (both days). Pasture allocation in the afternoon rather than in the morning decreased plasma concentration of ghrelin (P < 0.001) and cortisol (P < 0.001), with a smoothed trend on day 34 in the latter variable. To conclude, postponing the pasture allocation to afternoon increased the intake of WSC, favoring a glucogenic pattern of rumen fermentation and a rise of glucose and insulin levels in blood, although these effects were not consistent across the whole experimental period. Moreover, the afternoon grazing decreased the level of cortisol and ghrelin, suggesting a higher satiation-relaxing effect.

This study evaluated if dietary carbohydrate type (starch vs. fiber) can modulate glucose metabolism in ewes and goats in mid-lactation. At c.a. 95 d in milk (DIM), 20 ewes and 20 goats were subdivided into two groups. The first one (10 sheep and 10 goats) received a high-starch diet (HS; 24.1% starch, 36.4% NDF, 15.4% CP, DM basis) and the other (10 sheep and 10 goats) a highly-digestible fiber diet (HF; 10.5% starch, 46.8% NDF, 15.4% CP, DM basis), obtained by replacing corn and barley meal with soybean hulls. At 153 DIM, glucose tolerance tests (GTT) were performed on 10 sheep and 10 goats selected from each group. Diet was withdrawn in the afternoon of the day before the test. One mL of a 50% glucose solution per kg of BW was injected into the jugular vein of each animal. Blood samples were collected 15 min before and at 5, 10, 15, 30, 45, and 90 min after glucose injection. At 165 DIM, all the animals were subjected to blood postprandial sampling at 30, 60, 120, 180, and 240 min post feeding. Blood glucose was assayed by an enzymatic-colorimetric method. Blood glucose concentration data were analyzed by the PROC MIXED of SAS with repeated measurements. For GTT the incremental area under the curve (AUC), the fractional turnover rate (k), and the half-life were calculated and data were analyzed with a two-factor (diet within species and species) ANOVA. The -15-min glucose concentration was higher in sheep than goats (73.5 vs. 53.6 mg/dl; P < 0.005) but was not affected by diet. During the GTT, the mean blood glucose concentration was greater in sheep than goats (228.1 vs. 209.2 mg/dl; P < 0.05) and in HS goats than HF goats (217.9 vs. 198.6 mg/dl P < 0.01), whereas it did not differ between HS sheep and HF sheep. The values of AUC, k and half-life were not affected by species or diet. Regarding the postprandial sampling, mean blood glucose concentration was higher in sheep than goats (60.3 vs. 50.3 mg/dl; P < 0.001) and in HS goats than HF goats (52.2 vs. 48.1 mg/dl; P < 0.001), whereas it did not differ between HS sheep and HF sheep. In conclusion, it seems that the source of carbohydrates modulated blood glucose metabolism in goats but not in sheep.

Similar to most if not all pro-apoptotic members of the Bcl-2 family, Bid (and its truncated product t-Bid) triggers cell death via mitochondrial membrane permeabilization (MMP). This effect can be monitored in intact cells, upon microinjection of recombinant Bid protein into the cytoplasm, as well as in purified mitochondria, upon addition of Bid protein. Here we show that Bid-induced MMP can be inhibited, both in cells and in the cell-free system, by three pharmacological inhibitors of the permeability transition pore complex (PTPC), namely cyclosporin A, N-methyl-4-Val-cyclosporin A, and bongkrekic acid (a ligand of the adenine nucleotide translocase, ANT, one of the PTPC components). Bid effects on synthetic membranes were studied either in proteoliposomes or in synthetic bilayers subjected to electrophysiological measurements. Full length Bid preferentially permeabilizes membranes and induces the formation of large conductance channels at neutral pH, when added to liposomes or bilayers containing both purified ANT and Bax, yet has no or little effect combined with ANT or Bax alone. t-Bid acts on membranes containing ANT alone with the same efficiency as on those containing both ANT and Bax. These results suggest that the proapoptotic effects of Bid are mediated, at least in part, by its functional interaction with ANT, one of the major components of PTPC.

Abstract The proteolytic fragments of OprFs of Pseudomonas aeruginosa and Pseudomonas fluorescens were identified, respectively, as the first 175 and 177 amino acids from the N-terminal domain. They induced ion channels after reincorporation into planar lipid bilayers (85 and 75 pS, respectively, in 1 M NaCl). A similar conductance value (72 pS) was found for the eight β-strand OmpA N-terminal domain (OmpA171) of Escherichia coli. We conclude that the N-terminal domain of OprFs is sufficient to induce ion channels and the comparison with OmpA171, provides strong evidence of the existence of an eight-stranded β-barrel in the N-terminal domain of OprFs.

Many bioactive peptides, presenting an unstructured conformation in aqueous solution, are made resistant to degradation by posttranslational modifications. Here, we describe how molecular oligomerization in aqueous solution can generate a still unknown transport form for amphipathic peptides, which is more compact and resistant to proteases than forms related to any possible monomer. This phenomenon emerged from 3D structure, function, and degradation properties of distinctin, a heterodimeric antimicrobial compound consisting of two peptide chains linked by a disulfide bond. After homodimerization in water, this peptide exhibited a fold consisting of a symmetrical full-parallel four-helix bundle, with a well secluded hydrophobic core and exposed basic residues. This fold significantly stabilizes distinctin against proteases compared with other linear amphipathic peptides, without affecting its antimicrobial, hemolytic, and ion-channel formation properties after membrane interaction. This full-parallel helical orientation represents a perfect compromise between formation of a stable structure in water and requirement of a drastic structural rearrangement in membranes to elicit antimicrobial potential. Thus, distinctin can be claimed as a prototype of a previously unrecognized class of antimicrobial derivatives. These results suggest a critical revision of the role of peptide oligomerization whenever solubility or resistance to proteases is known to affect biological properties.