Effects of corn grain endosperm type and fineness of grind on site of digestion, ruminal digestion kinetics, and flow of nitrogen fractions to the duodenum in lactating dairy cows.

Our objective was to evaluate effects of corn grain endosperm type and fineness of grind on feed intake, feeding behavior, and productive performance of lactating cows. Eight ruminally and duodenally cannulated Holstein cows in mid lactation (130 ± 42 d in milk; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design with 21-d periods. A 2 × 2 factorial arrangement of treatments was used with main effects of corn grain endosperm type (floury or vitreous) and fineness of grind (fine or medium). Rations included alfalfa silage, corn treatments, protein supplement, minerals, and vitamins and were formulated to contain 29% starch, 27% neutral detergent fiber, 18.2% forage neutral detergent fiber, and 18% crude protein. Corn grain treatments supplied 86.2% of dietary starch. Endosperm was 25% vitreous for the floury treatment and 66% vitreous for the vitreous treatment. The floury treatment increased rate of starch degradation by 94% (19.2 vs. 9.9%/h) and decreased rate of starch passage by 38% (16.1 vs. 25.8%/h), increasing apparent ruminal starch digestibility by 117% (53.7 vs. 24.7%). The floury treatment increased total-tract starch digestibility by 8% (92.2 vs. 85.1%) despite 37% lower postruminal starch digestion for the floury treatment compared with vitreous corn (38.4 vs. 60.7% of starch intake). Fine grind size increased apparent ruminal starch digestibility by 52% (47.2 vs. 31.1%) compared with medium grind size by increasing the rate of starch degradation by 105% (19.5 vs. 9.5%/h) with no effect on rate of starch passage. However, total-tract starch digestibility was not affected by fineness of grind because postruminal starch digestibility was 37% greater for medium compared with fine grind size (57.2 vs. 41.9% of starch intake). Endosperm type did not affect flow of nitrogen (N) fractions to the duodenum or microbial N efficiency, whereas fine grind size increased duodenal flow of nonammonia N by increasing duodenal flow of microbial N by 22% compared with medium grind size (438 vs. 359 g/d) but did not affect apparent total-tract N digestibility. No interactions were detected for any measure of starch digestion, ruminal N metabolism, or flow of N fractions to the duodenum. Endosperm type greatly affected ruminal and total-tract starch digestibility independent of the fineness of grind of corn grain with no effects on flow of N fractions.

Effects of propionate concentration on short-term metabolism in liver explants from dairy cows in the postpartum period.

Our objective was to determine the temporal effects of increasing supply of propionate on propionate metabolism in liver tissue of dairy cows in the postpartum (PP) period. A total of 6 dairy cows [primiparous: n = 3, 9.00 ± 1.00 d PP (mean ± SD) and multiparous: n = 3; 4.67 ± 1.15 d PP] were biopsied for liver explants in a block-design experiment. Explants were treated with 3 concentrations of [13C3]sodium propionate of 1, 2, or 4 mM. Explants were incubated in 2 mL of Medium 199 supplemented with 1% BSA, 0.6 mM oleic acid, 2 mM sodium l-lactate, 0.2 mM sodium pyruvate, and 0.5 mMl-glutamine at 38°C and sampled at 0.5, 15, and 60 min. Increasing the concentration of [13C3]propionate increased total 13C% enrichment of propionyl coenzyme A (CoA), succinate, fumarate, malate, and citrate with time. Concentration of propionate did not affect total 13C% enrichment of hepatic glucose or acetyl CoA, but total 13C% enrichment increased with time for hepatic glucose. The 13C labeling from propionate was incorporated into acetyl CoA, but increased concentrations of propionate did not result in greater labeling of acetyl CoA. However, increases in 13C% enrichment of [M+4]citrate and [M+5]citrate concentrations of [13C3]propionate indicate propionate conversion to acetyl CoA and subsequent entry of acetyl CoA into the tricarboxylic acid cycle in dairy cows in the PP period. This research presents evidence that despite an increase in hepatic acetyl CoA concentration and general consensus on the upregulation of gluconeogenesis of dairy cows during the PP period, carbon derived from propionate contributes to the pool of acetyl CoA, which increases as concentration of propionate increases, in addition to stimulating oxidation of acetyl CoA from other sources. Because of the hypophagic effects of propionate, but importance of propionate as a glucose precursor, a balance of propionate supply to dairy cows could lead to improvements in dry matter intake, and subsequently, health and production in dairy cows.

Investigation of the bacterial retting community of kenaf (Hibiscus cannabinus) under different conditions using next-generation semiconductor sequencing.

The microbial communities associated with kenaf (Hibiscus cannabinus) plant fibers during retting were determined in an effort to identify possible means of accelerating this process for industrial scale-up. Microbial communities were identified by semiconductor sequencing of 16S rRNA gene amplicons from DNA harvested from plant-surface associated samples and analyzed using an Ion Torrent PGM. The communities were sampled after 96 h from each of three different conditions, including amendments with pond water, sterilized pond water, or with a mixture of pectinolytic bacterial isolates. Additionally, plants from two different sources and having different pretreatment conditions were compared. We report that the best retting communities are dominated by members of the order Clostridiales. These bacteria appear to be naturally associated with the plant material, although slight variations between source materials were found. Additionally, heavy inoculations of pectinolytic bacteria established themselves and in addition their presence facilitated the rapid dominance of the original plant-associated Clostridiales. These data suggest that members of the order Clostridiales dominate the community and are most closely associated with efficient and effective retting. The results further suggest that establishment of the community structure is first driven by the switch to anaerobic conditions, and subsequently by possible competition for nitrogen. These findings reveal important bacterial groups involved in fiber retting, and suggest mechanisms for the manipulation of the community and retting efficiency by modifying nutrient availability.

Controlled evaluation of the effects of hyperbaric oxygen therapy on the behavior of 16 children with autism spectrum disorders.

Hyperbaric oxygen therapy (HBOT) has been used to treat individuals with autism. However, few studies of its effectiveness have been completed. The current study examined the effects of 40 HBOT sessions at 24% oxygen at 1.3 ATA on 11 topographies of directly observed behavior. Five replications of multiple baselines were completed across a total of 16 participants with autism spectrum disorders. No consistent effects were observed across any group or within any individual participant, demonstrating that HBOT was not an effective treatment for the participants in this study. This study represents the first relatively large-scale controlled study evaluating the effects of HBOT at the level of the individual participant, on a wide array of behaviors.

Fat supplements affect fractional rates of ruminal fatty acid biohydrogenation and passage in dairy cows.

Rates of fatty acid biohydrogenation and passage were determined for fat supplements varying in saturation using lactating dairy cows. First-order fractional passage rates were determined by dividing the duodenal flux of fatty acids by their respective ruminal pool sizes. The determination of rates of biohydrogenation required the development of a model to account for the transfer of fatty acids among pools. Ruminally and duodenally cannulated multiparous Holstein cows (n = 8) were used in a replicated 4 x 4 Latin square design with 21-d periods. Treatments were control and a linear substitution of 25 g/kg supplemented fatty acids varying in saturation as follows: saturated (prilled hydrogenated free fatty acids), intermediate mix of saturated and unsaturated (calcium soaps of long-chain fatty acids), and partially unsaturated fatty acids. Passage rates of 16:0, 18:0, and total 18-carbon fatty acids were linearly decreased with increasing unsaturated fatty acids and the trans-18:1 fractional passage rate was quadratically affected with a maximum for the intermediate treatment. Increasing unsaturated fatty acids increased the extent of 18:2 and 18:3 biohydrogenation and decreased the extent of 18:1 and trans-18:1 biohydrogenation. Calcium salts did not protect PUFA from ruminal biohydrogenation despite a mean ruminal pH of 6.0, and unsaturated fatty acids decreased ruminal biohydrogenation of trans-18:1, resulting in increased duodenal flow of these fatty acids. The model allows a mechanistic description of ruminal biohydrogenation and determination of the extent of 18:1 biohydrogenation.

Adenosine kinase deficiency is associated with developmental abnormalities and reduced transmethylation.

Adenosine (Ado) kinase (ADK; ATP:Ado 5' phosphotransferase, EC 2.7.1.20) catalyzes the salvage synthesis of adenine monophosphate from Ado and ATP. In Arabidopsis, ADK is encoded by two cDNAs that share 89% nucleotide identity and are constitutively, yet differentially, expressed in leaves, stems, roots, and flowers. To investigate the role of ADK in plant metabolism, lines deficient in this enzyme activity have been created by sense and antisense expression of the ADK1 cDNA. The levels of ADK activity in these lines range from 7% to 70% of the activity found in wild-type Arabidopsis. Transgenic plants with 50% or more of the wild-type activity have a normal morphology. In contrast, plants with less than 10% ADK activity are small with rounded, wavy leaves and a compact, bushy appearance. Because of the lack of elongation of the primary shoot, the siliques extend in a cluster from the rosette. Fertility is decreased because the stamen filaments do not elongate normally; hypocotyl and root elongation are reduced also. The hydrolysis of S-adenosyl-L-homo-cysteine (SAH) produced from S-adenosyl-L-methionine (SAM)-dependent methylation reactions is a key source of Ado in plants. The lack of Ado salvage in the ADK-deficient lines leads to an increase in the SAH level and results in the inhibition of SAM-dependent transmethylation. There is a direct correlation between ADK activity and the level of methylesterified pectin in seed mucilage, as monitored by staining with ruthenium red, immunofluorescence labeling, or direct assay. These results indicate that Ado must be steadily removed by ADK to prevent feedback inhibition of SAH hydrolase and maintain SAM utilization and recycling.