Changes in daily energy amounts of main milk components (lactose, protein and fat) during the lactation of high-yielding dairy cows.

The aim of this study was to examine the changes of the daily energy amount of lactose, protein and fat throughout the lactations, and compare them to each other. A total of 309 Israeli Holstein-Friesian cows from one kibbutz were investigated in three lactations, and information was given for a period of five years from 1996 to the end of 2000. The distribution of milk components and milk yield during lactation, and changes of the absolute and relative energy amount in the different milk components were calculated and evaluated. The results showed changes in the energy content of milk and its different components throughout the lactation. Each component (fat, lactose and protein) is dominant in different periods during the lactation. The energy amount from fat reaches a peak first, between days 40 and 50. Lactose has a peak at about day 66 of lactation, and protein reaches the peak last, approximately at day 104 of lactation. It seems that this peak sequence is constant and it is considered to be physiological. It might be suggested that there is a regulation governing the secretion of the different components at different times, and only one component is dominant in a given period. Each component exerts negative and positive influences on the secretion of the other components, which interact with each other and are not fully independent.

Disappearance of ethanol from isolated sheep rumen.

The absorption of ethanol from the rumen was studied in three British Milk sheep equipped with a rumen cannula. After removal of the rumen content and washing the forestomachs several times the reticulo-omasal orifice was closed and through the cannula 20 or 60 ml ethanol and 2 ml Cr-EDTA were infused in physiological saline. The entire fluid volume was 3000 ml. At the start of the experiment (0 min) and subsequently in the 5th, 15th, 30th, 45th, 60th and 75th minutes samples were taken from the fluid present in the forestomachs. During the 75-min experiment the amount of ethanol gradually decreased in the rumen. The rate of disappearance varied according to concentration. The graph depicting the change of ruminal ethanol concentration shows a curve typical of passive transport. The equation describing the disappearance of ethanol was y = -0.0474x2 + 5.6544x + 10.869 after the administration of 20 ml ethanol, and y = -0.1377x2 + 19.541x - 24.606 after the infusion of 60 ml ethanol. It was established that ethanol was absorbed through the rumen wall by a passive transport process.

Effect of different fat sources on in vitro degradation of nutrients and certain blood parameters in sheep.

This study was designed to determine the effects of calcium salt of palm oil fatty acids (CS), hydroxyethylsoyamide (HESA), butylsoyamide (BSA) and soybean oil (SO) on degradation of crude protein and fibre in vitro, and on the blood plasma lipid parameters in vivo. Five mature wethers (body weight 75 kg) were fed five diets in a 5 x 5 Latin square experiment. The control diet consisted of 50% meadow hay and 50% concentrate with no added fat. The control diet was supplemented with CS, HESA, BSA, or SO. Fat was added at 3.5% of dietary dry matter (DM). The final ether extract content of the ration was near 6%. Each period lasted 20 days. Fat supplements, except HESA, consistently decreased the in vitro DM disappearance of soybean meal as compared to control. In contrast to the effect of other treatments, crude protein degradation was greatest in the test tubes with inocula obtained from sheep fed diet with HESA. Fat supplements equally inhibited the DM and fibre breakdown of alfalfa pellet. CS and HESA seemed to be less detrimental to in vitro fermentation of neutral detergent fibre (NDF) than BSA and SO. All fat supplements increased blood plasma triglyceride, cholesterol and total lipid content. Plasma concentration of cholesterol and total lipid was highest with SO. The inclusion of CS in the diet increased 16:0, while all fat supplements increased plasma 18:0 and decreased 16:1 and 18:1 fatty acid content. Plasma 18:2n-6 was not changed by feeding CS and SO. However, compared to the control diet, 18:2n-6 increased with 12 and 41% in plasma fatty acids when sheep were fed HESA and BSA, respectively. The results showed that plasma concentration of linoleic acid was enhanced more when the amide was synthesised from butylamine than when from ethanolamine.

Absorption of leucine, alanine and lysine from the rumen.

The absorption of three amino acids (leucine, alanine and lysine) from the washed, closed rumen was studied in a short-term (75 min) experiment in situ. The concentration of leucine and alanine did not change in the rumen during the experiment, while that of lysine continuously decreased, and 40% of the total lysine placed in the rumen was absorbed during the experimental period. The rate of absorption decreased in proportion to the fall of amino acid concentration.

Ovarian consequences of low dose peroral Fusarium (T-2) toxin in a ewe and heifer model.

The effect of low dose peroral Fusarium produced T-2 toxin intake upon the ovarian function was evaluated in ewes (n = 30; Trial 1) and heifers (n = 7; Trial 2). Half of the ewes and all of the heifers were fed rich, acidosis-inducing concentrate. The 30 ewes were divided into 6 groups of 5 animals each. They were given 0, 0.3 or 0.9 mg/day (0, 5 or 15 ug/kg) purified T-2 toxin per os for 21 days (3x2 factorial design). Four of the 7 heifers were fed 9 mg/day (25 ug/kg) of the same purified T-2 toxin for 20 days while 3 remained untreated. The estrus cycles in all animals were synchronized prior to the trials and the T-2 exposure was started in the mid-luteal phase. The acidic condition in the rumen was estimated by the determination of urinary net acid-base excretion. The ovarian activity was followed with blood sampling for progesterone on alternate days (Trial 1) or with ultrasonography and sampling for progesterone daily (Trial 2). All of the heifers and concentrate-fed ewes showed a compensated acidosis, during first two thirds of T-2 exposure. In Trial 1, ovarian malfunction manifested as lower P4 peak concentration in the midluteal phase, shortening of the CL lifespan and prolonged follicular phases. These malfunctions were detected in 3 and 3 ewes fed concentrate and 0.3 mg and 0.9 mg T-2 toxin. Lower P4 peak concentration was observed in 1 ewe fed regular diet and 0.9 mg T-2 toxin. None of the control and acidotic groups (0 mg T-2), or ewes fed regular diet with 0.3 mg T-2 showed any ovarian malfunction. In Trial 2, after PGF2, administration the ovulation occured later and the plasma progesterone level remained low (< 3 nmol/l) for a longer period in T-2 treated heifers, than their untreated control mates (5.0+/-0.7 vs 3.7+/-0.5 d, P<0.05 and 8.3+/-0.4 vs 6.3+/-0.9 d, P<0.01, respectively). These results show that the peroral T-2 intake can significantly retard the folliculus maturation and ovulation and perhaps the subsequent luteinisation also in ruminants kept on concentrate-rich diet.

Effect of methionine and its related compounds on rumen bacterial activity.

The effect of several methionine sources (L-methionine = L-MET; DL-methionine = DL-MET, DL-S-methyl-methionine-sulphonium-chloride = SMM; N-hydroxymethyl-DL-methionine-Ca = NHM; methionine-hydroxy-analog free acid = MHA; methionine-sulphoxide = MSO) on rumen bacterial growth was studied using a new methodical approach which utilises a methionine free assay medium (Bacto Methionine Assay Media, Difco) supplemented by increasing quantities of the methionine sources and inoculated with one drop of diluted rumen bacteria. The optical density was measured after 18 h incubation on 39 degrees C. L- and DL-MET promoted the highest growth response, while SMM and NHM exerted significantly (p < 0.05) lower optical densities. MHA and MSO showed no growth response. The methodical approach and the possible bacterial strains, which might have contributed to the growth response have been discussed.

Lectins as markers of rumen epithelial cell differentiation.

Lectins of different carbohydrate specificities (GNA (Galanthus nivalis), con A (Canavalia ensiformis), VFL (Vicia faba), PSL (Pisum sativum), LCA (Lens culinaris), PNA (Arachis hypogaea; with or without prior neuraminidase treatment), WGA (Triticum vulgare), SBA (Glycine max), UEA-I (Ulex europaeus), LPA (Limulus polyphemus), BS-I B4 (Bandeiraea simplicifolia, isolectin B4)) were explored for use as differentiation markers of rumen epithelial cells in vivo and in vitro. Lectins specific for mannose (GNA), mannose/glucose (con A, VFL, PSL and LCA), N-acetylglucosamine (WGA) or for N-acetylneuraminic acid (LPA) reacted generally with all types of rumen epithelial cell from both rumen tissue and cell culture. They were, therefore, not suitable markers of epithelial differentiation. SBA was unsuitable because, although it reacted with both tissue and cultured rumen epithelial cells, it was also bound to non-stratified areas of primary rumen epithelial cell cultures. Both BS-I B4 and PNA (after neuraminidase treatment) had to be ruled out because they did not react with differentiated rumen tissue epithelial cells, although they did bind to both stratified and non-stratified cultured cells. In contrast, UEA-I reacted strongly with differentiated rumen epithelial cells both from rumen tissue and cell cultures and therefore appears to be a good general marker for rumen epithelial cell differentiation.

The effect of tannin treatment and subsequent urea supplementation of sunflower meal on the in vitro digestibility of its crude protein for ruminants.

The effect of tannin treatment (TSFM) and subsequent urea supplementation (TSFM + U) on the digestibility of sunflower meal (SFM) protein was studied by means of a three-phase laboratory method simulating the ruminant's digestion. Under the influence of the ruminal fluid 67% of SFM protein, 62% of TSFM protein and 58% of TSFM + U protein was degraded. The pepsin and pancreatin digestibilities of rumen undegraded protein (UDP) were as follow: 58.2% (SFM), 56.6% (TSFM), 43.3% (TSFM + U), and 22.0% (SFM), 28.8% (TSFM), 17.5% (TSFM + U), respectively. The four fractions (dissolved protein, oligopeptides, amino acids, and ammonia) of rumen degradable protein (DP) were also determined: 85 to 92% of rumen degradable protein was recovered in these four fractions. Owing to tannic acid treatment the quantity of dissolved protein decreased and that of oligopeptides increased.

In vitro evaluation of protein degradability in the rumen and digestibility of undegraded protein.

A three-phase laboratory procedure suitable for predicting protein degradability in the rumen and digestibility of undegraded protein is reported. In the first phase the feed was incubated with starch and buffered rumen fluid. In the incubation mixture the viability of protease-active bacteria was checked by anaerobic culturing, whereas changes in protease activity were monitored by azocasein degradation. In the second and third phase rumen undegradable protein (UDP) was digested with pepsin and pancreatin, respectively. The measurements showed that 63.2, 5.2 and 4.7% of the crude protein of green lucerne was decomposed by rumen fluid, pepsin and pancreatin, respectively. Degradability of the crude protein of extracted sunflower meal was 68.3, 17.7 and 5.5% in the three phases, respectively. Repeated determination yielded crude protein degradabilities of 66.7, 27.1 and 5.1% for the three phases, respectively.

Effect of heat treatment and subsequent urea supplementation of sunflower meal on the in vitro ruminal degradability of crude protein content and its postruminal digestibility.

A three-phase laboratory procedure was used for predicting the degradability of the protein of extracted sunflower meal before (SFM) and after heat treatment (HSFM). The rumen fluid degraded 69.1% and 67.1% of the SFM and HSFM protein, respectively. The digestibility values of rumen undegraded protein (UDP) were 57.3% (SFM) and 57.0% (HSFM) with pepsin and 17.6% (SFM) and 15.9% (HSFM) with pancreatin. Urea supplementation practically did not alter the rumen degradability of HSFM protein, while the pepsin digestibility of UDP decreased to 47.2%. Four fractions (NH3, dissolved amino acids, oligopeptides and proteins) of rumen degradable crude protein (RDP) were also determined in vitro: 81 to 92% of the degraded crude protein was found in the fractions tested. Heat treatment reduced free NH3 content but did not alter the other three fractions. Urea supplementation decreased the quantity of NH3, peptides and proteins as well.

Influence of sodium butyrate on HeLa cell morphology and proliferation.

The effect of one-week exposure to sodium butyrate on HeLa S3 cell cultures was studied with special regard to influence on prekeratin synthesis, by comparison to cultures similarly treated with the known proliferation inhibitor hydroxyurea, and not treated. Like hydroxyurea, sodium butyrate inhibited cell proliferation to a considerable degree, but accounted additionally for an increase in membrane-bound alkaline phosphatase activity, cellular prekeratin synthesis, tonofilament number, and filament bundle formation. These phenomena unequivocally indicate that sodium butyrate acted as a specific stimulator of Hela (epithelial) cell differentiation. Similar differentiation phenomena can be observed during early spontaneous keratinization of the stratified horny epithelium.