Melatonin in edible plants identified by radioimmunoassay and by high performance liquid chromatography-mass spectrometry.

Melatonin, the chief hormone of the pineal gland in vertebrates, is widely distributed in the animal kingdom. Among many functions, melatonin synchronizes circadian and circannual rhythms, stimulates immune function, may increase life span, inhibits growth of cancer cells in vitro and cancer progression and promotion in vivo, and was recently shown to be a potent hydroxyl radical scavenger and antioxidant. Hydroxyl radicals are highly toxic by-products of oxygen metabolism that damage cellular DNA and other macromolecules. Herein we report that melatonin, in varying concentrations, is also found in a variety of plants. Melatonin concentrations, measured in nine different plants by radioimmunoassay, ranged from 0 to 862 pg melatonin/mg protein. The presence of melatonin was verified by gas chromatography/mass spectrometry. Our findings suggest that the consumption of plant materials that contain high levels of melatonin could alter blood melatonin levels of the indole as well as provide protection of macromolecules against oxidative damage.

[Mean retention time of 51Cr-EDTA and 103Ru-phenanthroline in the digestive tract of sheep and bulls fed straw pellets]. / Mittlere Verweildauer (mean retention time) von 51Cr-EDTA und 103Ru-Phenantrolin im Verdauungstrakt von Schafen und Bullen bei Fütterung von Strohpellets.

Two lots of straw pellets (supplemented with 10% molasses), produced either with a 5 mm sieve in a hammer mill (lot A) or with a 12 mm sieve (lot B) from wheat straw, were tested with 4 sheep (wethers, average live weight 43 kg) and 4 bulls (average 170 kg). After carrying out a digestibility experiment, the mean retention time (mrt), the 80%-excretion of the markers and the transit time were ascertained with the help of 51Cr-EDTA and 103Ru-phenanthroline. The digestibility of carbohydrates (both crude fibre and N-free extracts) was significantly higher for the bulls than for the sheep. Mrt, transit time and 80%-marker excretion were ascertained as follows: (Table: see text) The better digestion performance of carbohydrates from pelleted wheat straw in bulls in contrast to the sheep is due to the longer retention time of the digesta in the digestive tract of bulls. In connection with the considerably higher ruminating capacity of cattle in comparison to sheep, a longer retention time of the straw particles (Welch, 1982) in the reticulo-rumen must be considered.

[Comparative studies of the digestibility of wheat straw pellets with different proportions of concentrated feed in sheep and bulls. 2. Rumen fermentation studies]. / Vergleichende Untersuchungen an Schafen und Bullen zur Verdauung von Weizenstrohpellets mit unterschiedlichem Konzentratanteil. 2. Mitteilung. Untersuchungen zur Pansenfermentation.

4 sheep (wethers) and 4 bulls (130-140 kg live weight) received pellets of straw and concentrated feed of the charges 1-5 produced from the same wheat straw. The quota of wheat coarse meal in the pellets was, in the sequence 1 to 5:31.4; 29.7; 15.3; 11.5 and 7.8% (charge 5 contained in addition to this 7.4% dried sugar beet). The crude fibre content in the DM, in the same sequence, was as follows: 25.9; 28.1; 28.7; 31.7 and 34.4%. The total content of volatile fatty acids (VFA) in the rumen fluid of the sheep was between 96.6 and 97.8 mmol/l (all 5 charges) and in the rumen fluid of the bulls between 83.4 and 90.5 m mol/l. There were no significant differences between the groups. The molar acetic acid content after the feeding of charge 1 (poorer in crude fibre) was 67.4% (sheep) and 68.0% (bulls) and rose with the increasing crude fibre content in the case of charge 5 to 70.5% and 72.2% resp. The content of propionic acid did not rise in the pelleted rations with the growing cereal quota and, identically for sheep and bulls, amounted to 17.7 mol% and 17.8 mol% on an average of the 5 rations. The molar butyric acid content decreased significantly with both species with the growing crude fibre content of the pelleted charges. The sum of the VFA with branched chains (isobutyric acid, valeric acid and isovaleric acid) increased significantly in both species with the growing quota of cereal coarse meal in the pellet charges. In the bulls, however, the increase was distinctly steeper, which is probably connected with the significantly higher pH-value and a higher proteolysis rate in the rumen fluid of the bulls (charges 1 to 2) in comparison with the sheep.