Evaluating the Rumen Degradation of Novel Protected Gelatin Capsules Containing Fish Oil Fed to Lactating Dairy Cows.

The objective of this study was to assess the effects of feeding gelatin capsules containing fish oil, treated with alcoholic solutions of flavoring agents followed by drying, on lactation performance, rumen fatty acids content and milk enrichment of fatty acids. In Trial 1, four multiparous ruminally fistulated Holstein cows were randomly assigned to one of four dietary treatments sequences in a 4 × 4 Latin square design. Treatments consisted of (1) Control with no capsules, (2) Control plus 200 untreated capsules per cow/day, mixed with the TMR, (3) Control plus 200 treated capsules per cow/day placed directly into the rumen, (4) Control plus 200 treated capsules per cow/day, mixed with the TMR. In Trial 2, three fistulated Holstein and three fistulated Jersey multiparous cows were randomly assigned to three dietary treatments sequences in a replicated 3 × 3 Latin square design. Treatments consisted of (1) Control with no capsules fed to the cows, (2) Control plus 180 untreated capsules per cow/day, (3) Control plus 180 treated capsules per cow/day. Compared to control, feeding fish oil capsules significantly (Trial 1) or numerically (Trial 2) reduced milk fat concentration and yield. Furthermore, in both trials, the feeding of untreated or treated capsules had no effect on animal performance or milk composition. In both trials, compared to controls, supplementing the diet with fish oil capsules consistently increased total trans C18:1 isomers and DHA concentration in the rumen and milk fat. However, for both trials, capsule protection treatment had a minimal effect on the concentration of any of the reported rumen and milk fatty acids. When assessed under laboratory control conditions, due to water absorption, the treated capsule weight was increased by 40% while resistance to pressure decreased by 84% after 2 h of incubation in water. The results of this study suggest that due to a reduction in the capsule shell's resistance to abrasion, treated capsules marginally prevented the release of fish oil in the rumen.

Revisiting the challenges of training Maternal Fetal Medicine fellows in chorionic villus sampling.

BACKGROUND: More than a decade ago, researchers described a survey of Maternal Fetal Medicine fellows that showed that chorionic villus sampling training was limited for Maternal Fetal Medicine fellows in the United States. Prenatal screening and diagnosis have rapidly evolved since then and include the introduction of noninvasive aneuploidy screening that uses cell-free fetal DNA. Yet, chorionic villus sampling remains the only method available for first-trimester genetic diagnosis. OBJECTIVE: This study evaluated the chorionic villus sampling training of Maternal Fetal Medicine fellows with respect to availability, competency standards, and education methods. STUDY DESIGN: In November 2015, an electronic survey was sent to Maternal Fetal Medicine fellows and fellowship directors of accredited Maternal Fetal Medicine fellowship programs in the United States. RESULTS: Fifty-eight percent of fellows (179/310) and 46% of program directors (35/76) responded. Ninety-five percent of Maternal Fetal Medicine fellows think that invasive diagnostic testing is essential to their training; 100% of fellows have amniocentesis training; and 65% have chorionic villus sampling training. The median number of chorionic villus sampling procedures that are expected during a fellowship in those who trained was 10. Eighty-eight percent of fellows and 89% of program directors state that chorionic villus sampling training could be better; 89% of fellows and 97% of directors would like access to simulated models. Barriers to training included lack of patients (71%) and lack of proficient attending supervisors (43%). CONCLUSION: Since the last survey, >10 years ago, chorionic villus sampling training has declined further. A decrease in the number of procedures that are performed is the leading barrier to this training.

Lipid feeding and milk fat depression.

Diets fed to cattle contain mostly unsaturated fatty acids supplied in grains and forages, by-products, and fat supplements. Lipid intake by dairy cattle must be restricted to prevent alterations of microbial populations in the rumen that can negatively affect milk yield. Unsaturated fatty acids consumed by cattle are extensively metabolized through biohydrogenation, intermediates of which include conjugated linoleic acid (CLA) and trans-monoenoic acid isomers. Three specific CLA intermediates of biohydrogenation have been shown to cause milk fat depression in dairy cattle through coordinated suppression of mammary lipogenic genes by a transcription factor that is a central regulator of lipid synthesis.

Identification of enriched conjugated linoleic acid isomers in cultures of ruminal microorganisms after dosing with 1-(13)C-linoleic acid.

Most studies of linoleic acid biohydrogenation propose that it converts to stearic acid through the production of cis-9 trans-11 CLA and trans-11 C18:1. However, several other CLA have been identified in ruminai contents, suggesting additional pathways may exist. To explore this possibility, this research investigated the linoleic acid biohydrogenation pathway to identify CLA isomers in cultures of ruminai microorganisms after dosing with a (13)C stable isotope. The (13)C enrichment was calculated as [(M+1/M)×100] in labeled minus unlabeled cultures. After 48 h incubation, significant (13)C enrichment was observed in seven CLA isomers, indicating their formation from linoleic acid. All enriched CLA isomers had double bonds in either the 9,11 or 10,12 position except for trans-9 cis-11 CLA. The cis-9 trans-11 CLA exhibited the highest enrichment (30.65%), followed by enrichments from 21.06 to 23.08% for trans-10 cis-12, cis-10 trans-12, trans-9 trans-11, and trans-10 trans-12 CLA. The remaining two CLA (cis-9 cis-11 and cis-10 cis-12 CLA) exhibited enrichments of 18.38 and 19.29%, respectively. The results of this study verified the formation of cis-9 trans-11 and trans-10 cis-12 CLA isomers from linoleic acid biohydrogenation. An additional five CLA isomers also contained carbons originating from linoleic acid, indicating that pathways of linoleic acid biohydrogenation are more complex than previously described.

Biohydrogenation of linolenic acid to stearic acid by the rumen microbial population yields multiple intermediate conjugated diene isomers.

The current literature suggests that linolenic acid biohydrogenation converts to stearic acid without the formation of CLA. However, a multitude of CLA were identified in the rumen that are generally attributed to linoleic acid biohydrogenation. This study used a stable isotope tracer to investigate the biohydrogenation intermediates of (13)C-linolenic acid, including CLA. A continuous culture fermenter was used to maintain a mixed microbial population obtained from the rumen of cattle at pH 6.5 for 6 d. The mixed fermenter contents were then transferred to batch cultures containing either (13)C-labeled or unlabeled linolenic acid, which were run in triplicate for 0, 3, 24, and 48 h. The (13)C enrichment was determined by GC-MS. After 48 h of incubation, 8 CLA isomers were significantly enriched, suggesting that these CLA isomers originated directly from linolenic acid. The cis-10, cis-12 CLA isomer exhibited the highest enrichment (21.7%), followed by cis-9, cis-11 and trans-8, trans-10 CLA. The enrichment of these 2 CLA isomers ranged from 20.1 to 21.1% and the remaining 5 CLA including cis-9, trans-11 CLA were <15.0%. A multitude of nonconjugated and partially conjugated 18:2 and 18:3 isomers was enriched during the 48 h of incubation. The results of this study confirm that mixed ruminal microbes are capable of the formation of several CLA and 18:3 isomers from linolenic acid, indicating that linolenic acid biohydrogenation pathways are more complex than previously reported.

Biodegradable microparticles based on poly(D,L-lactide) as a protective transport system in ruminant digestion.

Despite its abundance in their diet, cattle are unable to directly digest cellulose. The bovine digestive tract overcomes this problem via the rumen, a portion of the stomach containing mixed anaerobic bacteria. These microbes, while breaking down foodstuffs, also perform undesirable processes such as biohydrogenation, in which unsaturated fatty acids become saturated, with deleterious cardiovascular effects. An approach to preventing this saturation entailing the use of polymeric microspheres to encapsulate feed supplements is proposed, with a single emulsion, solvent evaporation method used to formulate poly(D,L-lactide) microparticles for delivery of unsaturated fatty acids to ruminant abomasum.

The production of 10-hydroxystearic and 10-ketostearic acids is an alternative route of oleic acid transformation by the ruminal microbiota in cattle.

The formation of hydroxystearic acid (HSA) and ketostearic acid (KSA) from oleic acid transformation has been documented in a variety of microbial species, including several isolated from the rumen of domesticated ruminant species. However, their ruminal production rates have not been established as influenced by fatty acid source. Dosing continuous cultures of mixed ruminal microorganisms with 1-(13C)-oleic acid increased the 13C enrichment of both HSA and KSA at 24 h postdosing, and showed that the majority (96 and 85%, respectively) of the HSA and KSA present in the 24-h samples originated from oleic acid. Several experiments using batch cultures of ruminal microorganisms showed that production of HSA and KSA was directly related to oleic acid input but was not affected by elaidic acid input, and that HSA was further metabolized to KSA but not to other fatty acids. When continuous cultures of ruminal microorganisms were supplemented with soybean oil or canola oil, production of 10-HSA + 10-KSA was related to oleic acid input but not to linoleic acid input. Daily production of 10-HSA + 10-KSA across treatments was 14.4 micromol/100 micromol oleic acid input into the cultures or 31.1 micromol/100 micromol oleic acid net loss. The results of this study quantify the formation of 10-HSA and 10-KSA from oleic acid transformation by ruminal microorganisms, and show that their accumulation in ruminal contents is directly related to the extent of oleic acid input and biotransformation by the rumen microbiota.

Isomerization of stable isotopically labeled elaidic acid to cis and trans monoenes by ruminal microbes.

A previous study showed that oleic acid was converted by mixed ruminal microbes to stearic acid and also converted to a multitude of trans octadecenoic acid isomers. This study traced the metabolism of one of these trans C18:1 isomers upon its incubation with mixed ruminal microbes. Unlabeled and labeled (18-[13C]trans-9 C18:1) elaidic acid were each added to four in vitro batch cultures with three cultures inoculated with mixed ruminal bacteria and one uninoculated culture. Samples were taken at 0, 12, 24, and 48 h and analyzed for 13C enrichment in component fatty acids by gas chromatography-mass spectrometry. At 0 h of incubation, enrichment was detected only in elaidic acid. By 48 h of incubation, 13C enrichment was 18% (P < 0.01) for stearic acid, 7% to 30% (P < 0.01) for all trans C18:1 isomers having double bonds between carbons six through 16, and 5% to 10% for cis-9 and cis-11 monoenes. After 48 h, 13C enrichment in the uninoculated cultures was only detected in the added elaidic acid. This study shows trans fatty acids exposed to active ruminal cultures are converted to stearic acid but also undergo enzymic isomerization yielding a multitude of positional and geometric isomers.

Microbial biohydrogenation of oleic acid to trans isomers in vitro.

Ruminant products are significant sources of dietary trans fatty acids. Trans fatty acids, including various conjugated linoleic acid isomers, have been shown to act as metabolic modifiers of lipid metabolism. Trans fatty acids originate from biohydrogenation of dietary unsaturated fatty acids by gut microbes; however, the exact synthetic pathways are unclear. It was our goal to examine the biohydrogenation pathway for oleic acid, where oleic acid is hydrogenated directly to stearic acid. Our objective in this study was to trace the time course of appearance of 13C in labeled oleic acid to determine if trans monoenes are formed from the 13C-labeled oleic acid or if the 13C appears only in stearic acid as described in reviews of earlier work. Enrichments were calculated from the mass abundance of 13C in major fatty acid fragments and expressed as a percentage of total carbon isotopomers. Significant 13C enrichment was found in stearic acid, oleic acid, trans-6, trans-7, and in all trans C18:1 in positions 9-16. We concluded that the biohydrogenation of oleic acid by mixed ruminal microbes involves the formation of several positional isomers of trans monoenes rather than only direct biohydrogenation to form stearic acid as previously described.