Fed Timothy Hay Research Articles

Effects of Olive (Olea europaea L.) Leaves with Antioxidant and Antimicrobial Activities on In Vitro Ruminal Fermentation and Methane Emission.

Simple SummaryOlives are cultivated mostly in the Mediterranean as well as in Asia Minor, Korea, Japan, and China. Olive oil is currently used as a food ingredient in human diet, and its consumption is gradually expanding in various countries. Therefore, olive cultivation and oil extraction produce a significant amount of byproducts; providing these byproducts as feed to livestock has been attempted for a long period. Economic, environmental, and nutritional considerations make the use of olive byproducts efficient and cost-effective as feed for ruminants. Among the olive byproducts, olive leaves (OLs) contain higher levels of polyphenols than olive fruits, and have a very high feed value. In this study, it was confirmed that methane production decreased during 12 h of in vitro fermentation, and the number of fat-utilizing microorganisms increased in the 5% OLs group. OLs were found to show antioxidant and antimicrobial activity. Moreover, the proportion of cellulose-degrading bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens increased in the 5% OLs group at 12 h and decreased at 24 h. Olive leaves are believed to be very useful as feed additives and supplements for ruminants.We evaluated whether olive leaves (OLs) are effective as feed additives and supplements for ruminants and the potential methane reduction effects during in vitro fermentation. Two Hanwoo cows (460 ± 20 kg) equipped with cannula were fed Timothy hay and corn-based feed 3% of the body weight at a ratio of 6:4 (8:30 a.m. and 5:00 p.m.). Ruminal fluid from the cows was collected and mixed before morning feeding. In vitro batch fermentation was monitored after 12 and 24 h of incubation at 39 °C, and OLs were used as supplements to achieve the concentration of 5% in the basal diet. At 12 h of fermentation, methane production decreased in the 5% OLs group compared to that in the control group, but not at 24 h. The proportion of cellulose-degrading bacteria, Fibrobacter succinogenes, Ruminococcus albus, and Ruminococcus flavefaciens, tended to increase in the 5% OLs group at 12 h. The amount of ammonia produced was the same as the polymerase chain reaction result for Prevotella ruminicola. At 12 h, the proportion of Prevotella ruminicola was significantly higher in the 5% OLs group. OLs may be used incorporated with protein byproducts or other methane-reducing agents in animal feed.

Nutritional requirements of Allisonella histaminiformans, a ruminal bacterium that decarboxylates histidine and produces histamine.

Histamine is an inflammatory agent that contributes to bovine laminitis. Cattle fed silage-containing rations often have large populations of Allisonella histaminiformans, but this obligate histidine-decarboxylating bacterium could not be isolated from cattle fed timothy hay. The growth of A. histaminiformans was stimulated by yeast extract, protein hydrolysates, and water-soluble extracts of alfalfa or corn silage. Extracts of alfalfa were more potent than corn silage. Because growth and histamine production were not stimulated by Casamino Acids or a mixture of purified amino acids, it appeared that A. histaminiformans requires peptides. The idea that A. histaminiformans requires peptides is consistent with the observation that alfalfa silages often have a large amount of peptide nitrogen.

Amino acid deamination by ruminal Megasphaera elsdenii strains.

When ruminal fluid from a cow fed timothy hay was serially diluted (10-fold increments into anaerobic broth containing 15 mg ml(-1) Trypticase), the low dilutions (< or =10(-6)) had optical densities greater than 2.0 and ammonia concentrations greater than 100 m M. The optical densities and ammonia concentrations of the 10(-8) and 10(-9) dilutions were very low, but large cocci were observed in the 10(-8) dilution. The large cocci were isolated and identified by 16S rDNA sequencing as Megasphaera elsdenii. The freshly isolated strain (JL1) grew well on Trypticase, but less than 4% of the amino acid nitrogen in Trypticase was converted to ammonia. Optical density and ammonia production were twice as great if Casamino acids were provided, and similar results were obtained with seven other strains (B159, AW106, YT91, LC1, T81, J1, and YZ70). Specific activities of deamination (based on Casamino acids) of the eight strains ranged from 100 (strain JL1) to 325 (strain B159) nmol mg protein(-1) min(-1). None of the strains could utilize branched-chain amino acids as an energy source for growth, but specific activities of branched-chain amino acid deamination ranged from 15 to 65 nmol mg protein(-1) min(-1). All eight of the M. elsdenii strains grew well in the presence of 5 micro M monensin, and only two of the strains were strongly inhibited by 20 micro M monensin. On the basis of these results, it appears that M. elsdenii is deficient in peptidase activity and can utilize only a few amino acids. Some M. elsdenii strains produced ammonia and branched-chain volatile fatty acids nearly as fast as obligate amino acid-fermenting ruminal bacteria, but the extent of this production was at least fourfold lower. Because all of the strains could tolerate 5 micro M monensin, it is unlikely that this feed additive would significantly inhibit M. elsdenii in vivo.

The effect of bovicin HC5, a bacteriocin from Streptococcus bovis HC5, on ruminal methane production in vitro.

Methane represents a loss of feed energy to ruminant animals, and nutritionists have sought methods of inhibiting ruminal methane production. When mixed ruminal bacteria (approximately 400 mg protein ml(-1)) from a cow fed timothy hay were incubated in vitro with carbon dioxide and hydrogen (0.5 atm) for less than 8 h, the first-order rate of methane production was 17 micromol ml(-1). Semi-purified bacteriocin from Streptococcus bovis HC5 (bovicin HC5) inhibited methane production, by as much as 50%, and even a low concentration of bovicin HC5 (128 activity units (AU) ml(-1)) caused a significant decrease. Mixed ruminal bacteria that were transferred successively retained their ability to produce methane from carbon dioxide and hydrogen, and the first-order rate of methane production did not decrease. Cultures that were treated with bovicin HC5 (128 AU ml(-1)) gradually lost their ability to produce methane, and methane was not detected after four transfers. These latter results indicated that ruminal methanogens could not adapt and become resistant to bovicin HC5. When the chromosomal DNA was amplified with 16S rDNA primers specific to archaea, digested with restriction enzymes (HhaI and HaeIII) and separated on agarose gels, approximately 12 fragments were observed. DNA from control and treated cultures (third transfer) had the same fragment pattern indicating bovicin HC5 was not selective. Given the perception that the routine use of antibiotics in animal feeds should be avoided, bacteriocins may provide an alternative strategy for decreasing ruminal methane production.

The effect of bovicin HC5, a bacteriocin from Streptococcus bovis HC5, on ruminal methane production in vitro

Methane represents a loss of feed energy to ruminant animals, and nutritionists have sought methods of inhibiting ruminal methane production. When mixed ruminal bacteria (approximately 400 mg protein ml −1) from a cow fed timothy hay were incubated in vitro with carbon dioxide and hydrogen (0.5 atm) for less than 8 h, the first-order rate of methane production was 17 μmol ml −1. Semi-purified bacteriocin from Streptococcus bovis HC5 (bovicin HC5) inhibited methane production, by as much as 50%, and even a low concentration of bovicin HC5 (128 activity units (AU) ml −1) caused a significant decrease. Mixed ruminal bacteria that were transferred successively retained their ability to produce methane from carbon dioxide and hydrogen, and the first-order rate of methane production did not decrease. Cultures that were treated with bovicin HC5 (128 AU ml −1) gradually lost their ability to produce methane, and methane was not detected after four transfers. These latter results indicated that ruminal methanogens could not adapt and become resistant to bovicin HC5. When the chromosomal DNA was amplified with 16S rDNA primers specific to archaea, digested with restriction enzymes ( HhaI and HaeIII) and separated on agarose gels, approximately 12 fragments were observed. DNA from control and treated cultures (third transfer) had the same fragment pattern indicating bovicin HC5 was not selective. Given the perception that the routine use of antibiotics in animal feeds should be avoided, bacteriocins may provide an alternative strategy for decreasing ruminal methane production.

Effect of feeding thoroughbred horses a high unsaturated or saturated vegetable oil supplemented diet for 6 months following a 10 month fat acclimation.

This study looked at the effect of feeding diets supplemented with either a predominantly saturated or unsaturated vegetable oil over a prolonged period to exercising horses. Eight Thoroughbred horses were assigned to 2 diet treatments and for 10 months were fed Timothy hay and oats, together with a fortified sweet feed supplemented with either a predominantly unsaturated (Un) or a saturated (S) vegetable oil so that approximately 19% DE (Digestible Energy) came from dietary fat and approximately 12% from either the Un or S source (AC). An increased amount of Un or S fortified sweet feed, replacing the oats, was then fed for a further 6 months (HF) so that approximately 27% DE came from fat and approximately 20% from the Un or S vegetable oil. Standardised incremental treadmill exercise (8-12 m/s) tests (STEP) and duplicate oral glucose tolerance tests (TOL) were carried out after 3, 6 and 9 months of the AC diet and after 3 and 6 months on the HF diet. There was no significant effect of dietary treatment or when the tests were undertaken (time) on the insulin or lactate responses to the STEP tests. Overall there was a significant (P < 0.05) effect of time and treatment on the glucose response, but there was no difference between treatments at the first and last tests or between the results for these tests or between the endAC and endHF tests. No significant effect of treatment or time was seen on the TOL glucose response (% change from Time '0') although there was a trend for the glucose concentrations to be lower and the insulin responses higher (nonsignificant) in the S treatment group. No significant effect of treatment on haematological parameters, monitored monthly, was found. Total protein and gamma glutamyl transferase remained within the normal range throughout. There was a significant effect of treatment (P < 0.05) on cholesterol and triglycerides with higher concentrations in the S group from the first (1 month) sample. Linoleic acid was the main fatty acid in all the 4 plasma lipid classes with slightly, but significant (P < 0.05), higher concentrations in Un for the cholesterol ester and phospholipid classes. There was no effect of time. Overall, the total resting plasma fatty acid content was significantly higher (P < 0.05) with S at the sample points (endAC and endHF). No adverse effects of feeding either diet on apparent coat condition or hoof appearance were seen apart from an apparent increase in the grease score. Many of the parameters assessed showed significant improvements with time (P < 0.05). In conclusion, no apparent adverse effects of feeding a diet supplemented with either an unsaturated or saturated vegetable oil for 6 months at approximately 20% DE after 10 months at approximately 12% DE were identified and there were no apparent disadvantages of feeding a saturated vegetable oil supplemented diet compared with an unsaturated one.

Use of potassium depletion to assess adaptation of ruminal bacteria to ionophores.

When mixed ruminal bacteria from cattle fed timothy hay were suspended in a medium containing a low concentration of potassium, monensin and lasalocid catalyzed a rapid depletion of potassium from cells. The ionophore-mediated potassium depletion was concentration dependent, and it was possible to describe the relationship with saturation constants. Mixed ruminal bacteria never lost more than 50% of their potassium (Kmax = 46%), and the concentrations of monensin and lasalocid needed to cause half-maximal potassium depletion (Kd) were 178 and 141 nM, respectively. When cattle were fed 350 mg of monensin per day, the ratio of ruminal acetate to propionate decreased from 4.2 to 2.9, and the Kd of monensin was eightfold greater than the value for mixed ruminal bacteria from control animals. Monensin supplementation also caused a twofold increase in the Kd of lasalocid. Lasalocid supplementation (350 mg per day) had no effect on the ruminal acetate-to-propionate ratio, but it caused a twofold increase in the Kd values of monensin and lasalocid. Increases in Kd occurred almost immediately after ionophore was added to the ration, and the Kd values returned to their prefeeding values within 14 days of withdrawal. Ionophore supplementation had no effect on the Kmax values, and approximately 50% of the population was always highly ionophore resistant. Because the Kd values of even adapted ruminal bacteria were low (< 1.5 microM), it appears that a large proportion of the ruminal ionophore is bound nonselectively to feed particles or ionophore-resistant bacteria.

Biological value of crude protein for sheep fed timothy hay

Protein balance trials with four sheep were conducted with mixtures of a single variety of grass hay containing 4.36–14.46% CP (N × 6.25). The data were used to calculate the minimum urinary CP excretion and the biological value of the ingested CP. Minimum daily urinary CP excretion was 1.08 g BW−0.75. Biological value was calculated to be 0.70 at a dietary CP content of 6.79%. Key words: Biological value, protein, sheep, timothy, hay

A Procedure for Measuring Peptides in Rumen Fluid and Evidence that Peptide Uptake Can Be a Rate-Limiting Step in Ruminal Protein Degradation

A relatively simple and sensitive procedure was developed to measure the concentration of peptides in rumen fluid. Feed particles and microorganisms were removed by centrifugation, and the supernatant was treated with perchloric acid (5% final concentration). Perchloric acid precipitated macromolecules that included protein, RNA, and DNA. Perchlorate was subsequently removed by precipitation with an excess of potassium carbonate. Ammonia was removed by boiling the alkaline sample. Supernatant samples were then analyzed for ninhydrin reactive material before and after HCl hydrolysis. Because ninhydrin reaction was 3 to 7.5 times greater after HCl hydrolysis, peptides rather than amino acids were the primary source of nonprotein, nonammonia nitrogen. Rumen fluid from a cow fed timothy hay and concentrate supplement (16% crude protein) contained more than 1200mg peptides/L (192mg N/L), 1h after feeding, and this value declined the prefeeding value of 400 mg/L (64mg N/L) by 8h after feeding. Comparison of ninhydrin reactivity with and without HCl hydrolysis indicated that peptides present before feeding contained more peptide bonds than the peptides soon after feeding. High pressure liquid chromatography revealed a variety of peaks soon after feeding and fewer dominant peaks 8h later. The data suggest that peptide uptake into rumen microorganisms can be a rate-limiting step in ruminal protein degradation.

Relative contributions of ruminal bacteria and protozoa to the degradation of protein in vitro.

Mixed ruminal microorganisms from a cow fed timothy hay and concentrate supplement (50:50) were incubated with various protein sources for 15 h (no carbohydrates or growth), and deamination was studied under enzyme-limiting substrate-excess conditions (n = 3). Addition of amphotericin (10 micrograms/ml) killed protozoa and decreased (P less than .05) ammonia production from killed bacteria but it had no effect (P greater than .05) on casein deamination. Monensin (5 micrograms/ml) also killed protozoa; however, it decreased (P less than .05) casein deamination to a much greater extent than amphotericin. Antibacterial antibiotics (penicillin G, polymixin B, cephalosporin C and streptomycin) greatly reduced (P less than .05) ammonia formation from casein. Isolated bacteria always produced more ammonia than isolated protozoa, but the difference was less with heat-treated, particulate proteins. Heated soybean protein was as soluble as heated casein but it was deaminated (P less than .05) at a faster rate by bacteria. Nonammonia-nonprotein N accumulation was greater (P less than .05) with the protozoa than bacteria. When incubations containing bacteria or protozoa were compared with combinations of protozoa and bacteria, the combinations always caused a synergistic increase in ammonia and decrease (P less than .05) in nonammonia-nonprotein N. These results suggest: soluble proteins were primarily degraded by bacteria; protozoa could contribute to the degradation of insoluble, particulate proteins; protozoa were limited in their ability to assimilate peptides (or amino acids); low molecular weight products could be fermented more readily by bacteria and monensin was toxic to protozoa, but decreases in ammonia were primarily due to action of monensin on bacteria.

Growth Studies with Calves and Rabbits Fed Timothy Hay Grown on Heavily Fertilized Soils ,

Summary This experiment was conducted to identify nutritional deficiencies in timothy hay grown on a heavily fertilized soil. When this hay was fed to calves with a concentrate mixture of degermed corn meal, nonfat dry milk solids or urea, vitamins A and D, cobalt, calcium, phosphorus, and common salt, the ration was deficient in iron, copper, and iodine, resulting in poor growth, poor appetite, anemia, and enlarged thyroids. Feeding iron and copper, either individually or in combination, did not correct these symptoms. Iodine supplementation corrected the thyroid condition but did not stimulate growth. When similar hay was fed to rabbits in a ration supplemented with wheat gluten, hydrogenated vegetable oil, dextrose, sodium chloride, and vitamins A and D, it also resulted in poor growth, anemia, and increased thyroid weight. Feeding of a ration containing 5% alfalfa prevented all these symptoms, but an equivalent amount of alfalfa ash or iodine prevented only the enlarged thyroid. The timothy hay apparently was deficient in iodine and some organic factor(s) which may be found in alfalfa hay.