Effects of nitrogen fertilizer and harvesting stage on photosynthetic pigments and phytol contents of Italian ryegrass silage

This study aimed to investigate the effects of nitrogen (N) fertilizer application and harvesting stage on the contents of chlorophyll, phytol and carotenoids (β‐carotene and lutein) in Italian ryegrass herbage before and after ensiling, and the extent of phytol preservation after ensiling. Three rates of N fertilizer (0, 60 and 120 kg N/ha) were applied by top‐dressing as an additional fertilizer. The herbage harvested at booting stage (27 weeks of age) or heading stage (29 weeks of age) were wilted for 1 day, then ensiled for 60 days using a small‐scale pouch system. In the pre‐ensiled herbages, increasing N fertilizer application increased the contents of crude protein and photosynthetic pigments, and these contents were also higher at the booting stage compared with the heading stage. In the silage, increasing N fertilizer application also increased the contents of crude protein, the photosynthetic pigments and their derivatives (pheophytin and pheophorbide), while harvesting stage did not affect the contents of β‐carotene, chlorophylls or pheophorbide. Nitrogen fertilizer application and early harvesting of herbage increased lutein and phytol contents in Italian ryegrass silage. Lutein and phytol in Italian ryegrass herbage are indicated to be well preserved during ensiling.     

Induction of proinflammatory cytokines and caspase-1 by leptin in monocyte/macrophages from holstein cows

The proliferation of peripheral blood mononuclear cells (PBMC) containing both monocyte/macrophages and T lymphocytes increased after treatment with T-cell mitogen (concanavalin A: Con A). PBMC treated with either leptin alone or combination of leptin and ConA showed enhanced proliferative activity by 10-40%, compared with those treated with ConA alone. In contrast, isolated T lymphocytes treated with leptin and ConA showed lowered proliferative activity than the ConA-treated alone, indicating that leptin induced production of some cytokines from monocyte/macrophages, that subsequently resulted in enhancement of T lymphocytes proliferation in PBMC. Among the cytokines examined, monocyte/monocytes constitutively expressed interleukin (IL)-1beta, IL-12p35, IL-18 mRNA, and faintly expressed tumor necrosis factor (TNF)-alpha and IL-12p40 mRNA. Leptin treatment augmented the monocyte/macrophages mRNA expression of only TNF-alpha and IL-12p40 to comparable levels of cells treated with lipopolysaccharide (LPS). However, leptin treatment increased monocyte/macrophages production of IL-1beta as well as TNF-alpha, and induced the mRNA expression of caspase-1, which is shown to mediate the conversion of latent pro-IL-1beta and pro-IL-18 to active forms. These results suggest that leptin directly acts on monocyte/macrophages to produce factors that induce T lymphocytes proliferation such as IL-12p35/p40 complex through IL-12p40 induction and IL-1beta/IL-18 production through caspase-1 induction.     

Effect of varying fermentation conditions with ensiling period and inoculum on photosynthetic pigments and phytol content in Italian ryegrass (Lolium multiflorum Lam.) silage

This study aimed to investigate the effect of an ensiling period (Experiment 1) and adding lactic acid bacteria (LAB, Experiment 2) on the changes in carotenoid, chlorophyll, and phytol in ensiled Italian ryegrass (IR, Lolium multiflorum Lam.). In Experiment 1, the IR herbage ensiled into plastic bags was analyzed for the contents of photosynthetic pigments and phytol over a 5‐week period. During the ensiling process, the β‐carotene content decreased (p < .05), whereas the lutein content did not change. Although the chlorophyll content decreased (p < .05) after ensiling, the phytol content barely changed until week 5. In Experiment 2, IR herbage was ensiled without additive, as a Control, or with LAB for 60 days. The pH was lower (p < .05) and lactic acid content was higher (p < .05) for the LAB silage than for the Control. The chlorophyll content in silage was not affected by the LAB; however, the β‐carotene content was higher (p < .05) for the LAB silage than for the Control. Phytol and lutein contents in the herbage did not change after ensiling. These results indicate that phytol and lutein in IR herbage can be preserved well in silage, irrespective of their fermentation condition.     

Inhibition of aflatoxin production in Aspergillus flavus by pyrazolines and pyrazoles

A new series of 1,3,5-triarylpyrazolines, obtained from 3, 4-dichloroacetophenone, were readily dehydrogenated by tetrachloro-o-benzoquinone at room temperature to the pyrazoles. The spectra and fluorescence of the compounds are discussed. The pyrazolines and pyrazoles did not significantly affect the mycelial growth of 19 fungal isolates, but at low concentrations, they inhibited aflatoxin production by Aspergillus flavus.     

Participatory rural appraisal in smallholder dairy systems in Tunisia

Participatory Rural Appraisal (PRA) was carried out by a multidisciplinary team on a total of 60 smallholder dairy farms in three different geographical areas of Tunisia. Farms with less than three cows were excluded. Those participating had between three and 10 cows. Average milk production ranged between 8 and 32 litres per cow per day. 70% or over of milk produced was sold off the farms. Average inter-calving intervals — measured from month of calving only — ranged from 12.9 months to 19. Age at first calving varied from two to nearly three years. Most work was done by the families. PRA revealed that the farmers in all three regions perceived unbalanced nutrition, which included availability of forages, to be the most important constraint, followed by poor reproductive efficiency. Reseeding with new species was instituted for grazing and hay. Farmers from the different regions were taken on exchange visits to see how these approaches worked. Training in reproductive management and milking hygiene was introduced. Seasonal ration formulation depending on local forage analysis was instituted. Two farms are participating in a programme of evaluation of olive oil extraction by-product as a ruminant feed. Partial budget analysis of these interventions will be carried out.     

Hopeaphenol: the first resveratrol tetramer in wines from North Africa

Grapes and wines are now known to constitute a rich source of phenolics such as stilbenes and flavonoids. These compounds have been shown to have cancer chemopreventive activity and potential beneficial effects on cardiovascular diseases thanks to their antioxidant and antiplatelet properties. However, because little is known about African wines and their phenolic compositions, we investigated wine samples from North Africa. A three-step method was used for the fractionation of the Merlot variety wine: column chromatography followed by centrifugal partition chromatography and reversed-phase semipreparative high-performance liquid chromatography (HPLC). Six polyphenolic compounds of the Merlot variety (from Algeria) were isolated and identified by NMR spectroscopy, five of which are known (trans-resveratrol, trans-piceid, trans-epsilon-viniferin, pallidol, and astilbin) and one that is reported for the first time in wine, (+)-hopeaphenol, a stilbene tetramer. Furthermore, these molecules were quantified in 10 commercial wines from North Africa by means of an analytical HPLC system coupled with diode array detection. Differences in concentrations were found ranging in mg/L from 4.6 to 45 (trans-piceid), 0.66 to 3.45 (trans-resveratrol), 0.2 to 1.2 (trans-epsilon-viniferin), 0.2 to 9.2 (pallidol), 0.3 to 3.8 (hopeaphenol), and 10.8 to 24.22 (astilbin). Such a high level of pallidol and astilbin has never been recorded in wine. North African wines may contribute to a significant proportion of dietary intake of stilbene and astilbin, which may have health benefits.