Fatty acid concentration of plasma, muscle, adipose and liver from beef heifers fed an encapsulated n-3 polyunsaturated fatty acid supplement.

Increasing the content of polyunsaturated fat in the human diet is a priority for reducing cardiovascular disease and cancer risks. Beef has the potential to contribute to the polyunsaturated fat content in the human diet; however, ruminants cannot synthesise many long-chain fatty acids de novo; they require dietary supplementation. The objectives of the current study were to evaluate (i) the effect of a partially rumen protected n-3 long-chain polyunsaturated fatty acid (LC-PUFA) dietary supplement on the fatty acid composition of muscle (Longissimus dorsi), adipose and liver tissues of beef heifers and (ii) the usefulness of blood plasma as a predictor of tissue concentrations of specific fatty acids. Charolais crossbred heifers (n = 20) were assigned to one of two isolipid dietary treatments namely palmitic acid (control) or an n-3 LC-PUFA supplement for a 91-day period. Blood plasma and adipose tissue samples were taken to determine the temporal effect of these diets on fatty acid composition (days 0, 10, 35 and 91), while liver and muscle samples were taken following slaughter. Dietary lipid source did not influence animal growth rate or body condition score. At day 91, the percentage differences between control and n-3 LC-PUFA heifers in concentrations of eicosapentaenoic acid were +61, +176 and +133 % in liver, muscle and adipose, respectively. For docosahexaenoic acid, at the same time point, the percentage differences were +57, +73 and +138 % for liver, muscle and adipose, respectively. Medium-to-strong positive correlation coefficients were evident for liver and plasma fatty acids, in particular, there were positive relationships with concentrations of total saturated fatty acid (SFA), total n-6 PUFA and total n-3 PUFA. This trend also extended to both the ratio of PUFA to SFA (slope (ß1) = 0.56 ±â€¯0.167, intercept (ß0) = 0.56, R2 = 0.61, P < 0.05) and the ratio of n-6 to n-3 PUFA (ß1 = 0.15 ±â€¯0.054, ß0 = 0.24, R2 = 0.52, P < 0.05). A strong correlation was also detected in the ratio of n-6 to n-3 in plasma and muscle tissue of heifers fed the n-3 LC-PUFA diet (ß1 = 0.53 ±â€¯0.089, ß0 = -0.31, R2 = 0.83, P < 0.001). The results of this study show that the n-3 LC-PUFA can be readily increased through targeted supplementation and that plasma concentrations of n-3 LC-PUFA are useful predictors of their concentrations in a number of economically important tissues.

Effect of dietary n-3 polyunsaturated fatty acid supplementation and post-insemination plane of nutrition on systemic concentrations of metabolic analytes, progesterone, hepatic gene expression and embryo development and survival in beef heifers.

Nutrition, and particularly dietary energy intake, plays a fundamental role in reproductive function in cattle. There is some evidence that supplemental omega-3 dietary polyunsaturated fatty acids (n-3 PUFA) can exert positive effects on fertility. The objectives of this study were to evaluate the effect of dietary n-3 PUFA supplementation, post-insemination energy plane of nutrition and their interaction on embryo survival in cattle. Crossbred beef heifers (n = 185) were individually offered barley straw ad libitum and 6 kg DM of concentrate supplemented with either a rumen-protected source of saturated fatty acid (palmitic; control, CON) or a partially rumen-protected n-3 PUFA-enriched supplement (n-3 PUFA). Estrous was synchronised using two injections of PG administered at 11-d intervals and following artificial insemination (AI = Day 0) 179 heifers exhibiting oestrus were inseminated and assigned to one of two dietary treatments: (i) remain on their pre-insemination high dietary plane of nutrition (High) or (ii) restricted to 0.6 × estimated maintenance energy requirements (Low) in a 2 × 2 factorial design. The heifers were then maintained on their assigned diets until slaughter and embryo recovery on Day 16 (n = 92) or pregnancy diagnosis by ultrasound scanning at Day 30 post-AI (n = 87). Plasma concentrations of fatty acids, metabolites, insulin, progesterone (P4) and insulin-like growth factor 1 (IGF-1) were measured at appropriate intervals. Hepatic expression of mRNA for aldo-keto reductase (AKR1C), cytochrome P450 2C (CYP 2C) and cytochrome P450 3A (CYP 3A) was examined. The n-3 PUFA supplementation increased plasma n-3 PUFA concentration (P < 0.05) and reduced n-6: n-3 PUFA ratio (P < 0.05). Plasma IGF-1 was higher for n-3 PUFA relative to the CON (P < 0.05) and for High compared with Low plane of nutrition post-AI (P < 0.05) groups. A low plane of nutrition post-AI increased plasma concentrations of progesterone from Days 7-16 after insemination (P < 0.001) but reduced embryo length (P < 0.001). Supplementation with n-3 PUFA reduced and tended to reduce hepatic expression of CYP2C (P = 0.01) and CYP3A (P = 0.08), respectively. However, while dietary n-3 PUFA supplementation and an abrupt reduction in nutrient status following insemination elevated plasma concentrations of n-3 PUFA and mid and late phase P4, respectively, there was no effect of either PUFA supplementation or post-insemination plane of nutrition on embryo survival.

Ibrutinib significantly inhibited Bruton's tyrosine kinase (BTK) phosphorylation,in-vitro proliferation and enhanced overall survival in a preclinical Burkitt lymphoma (BL) model.

Pediatric and adult patients with recurrent/refractory Burkitt lymphoma (BL) continue to have poor outcomes, emphasizing the need for newer therapeutic agents. Bruton's tyrosine kinase (BTK) is activated following B-cell receptor stimulation and in part regulates normal B-cell development. Ibrutinib, a selective and irreversible BTK inhibitor, has been efficacious in chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), Waldenström's macroglobulinemia, and marginal zone lymphoma. In this study, we investigated the efficacy of ibrutinib alone and in selective adjuvant combinations against BL in-vitro and in a human BL xenografted immune-deficient NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) mouse model. Our data demonstrated that phospho-BTK level was significantly reduced in BL cells treated with ibrutinib (p < 0.001). Moreover, we observed a significant decrease in cell proliferation as well as significant decrease in IC50 of ibrutinib in combination with dexamethasone, rituximab, obinutuzumab, carfilzomib, and doxorubicin (p < 0.001). In-vivo studies demonstrated ibrutinib treated mice had a significantly prolonged survival with median survival of mice following ibrutinib treatment (32 days) (24 days) (p < 0.02). In conclusion, our findings demonstrate the significant in-vitro and preclinical in-vivo effects of ibrutinib in BL. Based on our preclinical results in this investigation, there is an on-going clinical trial comparing overall survival in children and adolescents with relapsed/refractory BL treated with chemoimmunotherapy with or without ibrutinib (NCT02703272).

Impact of beneficial bacteria supplementation on the gut microbiota, colony development and productivity of Apis mellifera L.

Honey bees are important pollinators of several crops and ecosystems, having a great ecological and economic value. In Europe, the restricted use of chemicals and therapeutic agents in the beekeeping sector has stimulated the search for natural alternatives with a special focus on gut symbionts. The modulation of the gut microbiota has been recognised as a practical and successful approach in the entomological field for the management of insect-related problems. To date, only a few studies have investigated the effect of bacterial supplementation on the health status of colonies, colony productivity and gut symbionts. To this purpose, a preparation of sugar syrup containing bifidobacteria and lactobacilli isolated from bee gut was sprayed on the frames of an apiary located in open field once a week for four weeks. Treated and control hives were monitored for two months for brood extension, honey and pollen harvest. The presence of beneficial gut microorganisms within bee gut was investigated with denaturing gradient gel electrophoresis and next generation sequencing. The administered bacteria led to a significant increase of brood population (46.2%), pollen (53.4%) and harvestable honey in honey supers (59.21%). Analysis of the gut microbiota on the new generation of bees in treated hives showed an increase in relative abundance of Acetobacteraceae and Bifidobacterium spp., which are known to be involved in bee nutrition and protection.

The effect of dietary supplementation of algae rich in docosahexaenoic acid on boar fertility.

The objective of this study was to assess the effects of dietary supplementation of a commercial algal product rich in docosahexaenoic acid (DHA) on boar fertility as assessed in vitro and in vivo. Boars were fed one of three experimental diets for 19 weeks: (i) Control (Ctl) diet (n = 31), (ii) Ctl diet plus 75g All-G-Rich per day (n = 31) or (iii) Ctl diet plus 150g All-G-Rich per day (n = 30). Parameters assessed were (i) raw semen quality; volume, sperm concentration, total motility and morphology (ii) liquid semen quality; progressive motility, viability, hypotonic resistance and acrosomal integrity (iii) frozen-thawed semen quality; motility, thermal stress, viability, membrane fluidity and mitochondrial activity (iv) sperm and seminal plasma (SP) fatty acid composition (FAC) (v) total antioxidant capacity (TAC) of SP and (vi) farrowing rates and litter sizes of sows (n = 1158) inseminated with liquid semen. Boars consuming 75g All-G-Rich had a larger semen volume (P < 0.05) and a higher total sperm number (P < 0.01) than the Ctl treatment, however, there was no effect of treatment on any other semen quality parameter (P > 0.05). There was no effect of dietary treatment on the FAC and TAC of SP or on farrowing rate and litter size (P > 0.05). There was an effect of dietary treatment on the FAC of sperm, represented by an 1.72 and 1.60 fold increase in the DHA content for 75 and 150g treatments, respectively, compared to the Ctl treatment. In conclusion, a significant increase in semen volume and total sperm number in boars supplemented 75g All-G-Rich daily, resulted in an increase in production of 3 to 4 more doses per ejaculate, thus, indicating that the feeding regime described within this study has the potential for increasing the output of boar studs.

Influence of GABA and GABA-producing Lactobacillus brevis DPC 6108 on the development of diabetes in a streptozotocin rat model.

The aim of this study was to investigate if dietary administration of γ-aminobutyric acid (GABA)-producing Lactobacillus brevis DPC 6108 and pure GABA exert protective effects against the development of diabetes in streptozotocin (STZ)-induced diabetic Sprague Dawley rats. In a first experiment, healthy rats were divided in 3 groups (n=10/group) receiving placebo, 2.6 mg/kg body weight (bw) pure GABA or L. brevis DPC 6108 (~10(9)microorganisms). In a second experiment, rats (n=15/group) were randomised to five groups and four of these received an injection of STZ to induce type 1 diabetes. Diabetic and non-diabetic controls received placebo [4% (w/v) yeast extract in dH2O], while the other three diabetic groups received one of the following dietary supplements: 2.6 mg/kg bw GABA (low GABA), 200 mg/kg bw GABA (high GABA) or ~10(9) L. brevis DPC 6108. L. brevis DPC 6108 supplementation was associated with increased serum insulin levels (P<0.05), but did not alter other metabolic markers in healthy rats. Diabetes induced by STZ injection decreased body weight (P<0.05), increased intestinal length (P<0.05) and stimulated water and food intake. Insulin was decreased (P<0.05), whereas glucose was increased (P<0.001) in all diabetic groups, compared with non-diabetic controls. A decrease (P<0.01) in glucose levels was observed in diabetic rats receiving L. brevis DPC 6108, compared with diabetic-controls. Both the composition and diversity of the intestinal microbiota were affected by diabetes. Microbial diversity in diabetic rats supplemented with low GABA was not reduced (P>0.05), compared with non-diabetic controls while all other diabetic groups displayed reduced diversity (P<0.05). L. brevis DPC 6108 attenuated hyperglycaemia induced by diabetes but additional studies are needed to understand the mechanisms involved in this reduction.

γ-Aminobutyric acid production by culturable bacteria from the human intestine.

AIMS: To assess the ability of human intestinally derived strains of Lactobacillus and Bifidobacterium to produce γ-aminobutyric acid (GABA). METHODS AND RESULTS: Strains of Lactobacillus and Bifidobacterium were grown in medium containing monosodium glutamate (MSG). Growth of the bacteria and conversion of MSG to GABA were measured. Of 91 intestinally derived bacteria assessed, one Lactobacillus strain and four strains of Bifidobacterium produced GABA. Lactobacillus brevis DPC6108 was the most efficient of the strains tested, converting up to 90% [corrected] of MSG to GABA. The ability of the cultured intestinal strains to produce GABA was investigated using a simple pH-controlled anaerobic faeces-based fermentation, supplemented with 30 mg ml⁻¹ MSG. The addition of Lact. brevis DPC6108 to a faeces-based fermentation significantly increased the GABA concentration (P < 0·001), supporting the notion that this biosynthesis could occur in vivo. CONCLUSIONS: The production of GABA by bifidobacteria exhibited considerable interspecies variation. Lactobacillus brevis and Bifidobacterium dentium were the most efficient GABA producers among the range of strains tested. The addition of Lact. brevis DPC6108 to the culturable gut microbiota increased the GABA concentration in fermented faecal slurry at physiological pH. SIGNIFICANCE AND IMPACT OF THE STUDY: Identification of optimal MSG conversion to GABA by particular cultured elements of the commensal intestinal microbiota and the demonstration that this can occur under simulated in vivo conditions offer new prospects for microbiota modulation to promote health.

Modification of the technical properties of Lactobacillus johnsonii NCC 533 by supplementing the growth medium with unsaturated fatty acids.

The aim of this study was to investigate the influence of supplementing growth medium with unsaturated fatty acids on the technical properties of the probiotic strain Lactobacillus johnsonii NCC 533, such as heat and acid tolerance, and inhibition of Salmonella enterica serovar Typhimurium infection. Our results showed that the membrane composition and morphology of L. johnsonii NCC 533 were significantly changed by supplementing a minimal Lactobacillus medium with oleic, linoleic, and linolenic acids. The ratio of saturated to unsaturated plus cyclic fatty acids in the bacterial membrane decreased by almost 2-fold when minimal medium was supplemented with unsaturated fatty acids (10 µg/ml). The subsequent acid and heat tolerance of L. johnsonii decreased by 6- and 20-fold when the strain was grown in the presence of linoleic and linolenic acids, respectively, compared with growth in oleic acid (all at 10 µg/ml). Following acid exposure, significantly higher (P < 0.05) oleic acid content was detected in the membrane when growth medium was supplemented with linoleic or linolenic acid, indicating that saturation of the membrane fatty acids occurred during acid stress. Cell integrity was determined in real time during stressed conditions using a fluorescent viability kit in combination with flow cytometric analysis. Following heat shock (at 62.5°C for 5 min), L. johnsonii was unable to form colonies; however, 60% of the bacteria showed no cell integrity loss, which could indicate that the elevated heat inactivated vital processes within the cell, rendering it incapable of replication. Furthermore, L. johnsonii grown in fatty acid-enriched minimal medium had different adhesion properties and caused a 2-fold decrease in S. enterica serovar Typhimurium UK1-lux invasion of HT-29 epithelial cells compared with bacteria grown in minimal medium alone. This could be related to changes in the hydrophobicity and fluidity of the membrane. Our study shows that technical properties underlying probiotic survivability can be affected by nutrient composition of the growth medium.

Optimization of a reconstituted skim milk based medium for enhanced CLA production by bifidobacteria.

AIMS: To determine the effect of a range of supplements on the bioconversion of linoleic acid to conjugated linoleic acid (CLA) by Bifidobacterium breve NCIMB 702258 in reconstituted skim milk (RSM). RESULTS: Seven supplements (yeast extract, casein hydrolysate, tryptone, l-cysteine hydrochloride, sodium acetate, sodium butyrate and sodium propionate) were identified as increasing the bioconversion of linoleic acid to c9, t11 CLA. Using these supplements, the percentage bioconversion of linoleic acid (0.35 mg ml(-l)) to the c9, t11 CLA isomer was elevated from 15.5 +/- 1.1% in 20% RSM (w/v) to 48.1 +/- 2.2% in the supplemented RSM. Through additional supplementation of 20 mg m1(-1) inulin and optimization of inoculum and linoleic acid concentration, the percentage bioconversion to c9, t11 CLA was increased to 55.0 + 3.2%. CONCLUSIONS: Through supplementation, the concentration of CLA produced by bifidobacteria in RSM can be increased to levels comparable to those observed in the synthetic medium cys-MRS. SIGNIFICANCE AND IMPACT OF THE STUDY: The impact of 22 supplements on the production of the c9, t11 CLA isomer by the strain B. breve NCIMB 702258 in milk has been determined. The results provide an understanding of the factors, which influence CLA production by bifidobacteria in RSM.

Effect of level of dietary n-3 polyunsaturated fatty acid supplementation on systemic and tissue fatty acid concentrations and on selected reproductive variables in cattle.

Reproductively normal crossbred beef heifers were individually offered a diet of barley straw and concentrate supplemented with one of four levels of a fish oil (FO) enriched supplement. Following oestrous cycle synchronisation, blood samples were collected at appropriate intervals for the measurement of progesterone (P(4)), oestradiol (E(2)), fatty acids, insulin-like growth factor 1 (IGF-1) and metabolites. On days 15 and 16 of the cycle, oxytocin was administered intravenously and the prostaglandin F(2alpha) (PGF(2alpha)) response was measured as venous concentrations of 13,14-dihydro-15-keto PGF(2alpha) (PGFM). The heifers were slaughtered on days 17 or 18 of the oestrous cycle and endometrial tissue, rumen fluid and follicular fluid were collected for determination of fatty acid concentrations. In general there was no effect (P>0.05) of diet on plasma P(4) or E(2) concentrations. Increasing FO supplementation increased CL diameter on day 7 post-oestrus (P<0.0001) but had no effect on diameter on day of slaughter (P>0.05). On day 15, PGFM concentration was greater on the highest level of FO supplementation compared to controls (P<0.05), however, there were no differences between other diet comparisons (P>0.05). There was no effect of diet on PGFM concentration on day 16 (P>0.05). There was a strong positive relationship between plasma and uterine endometrial concentrations of both EPA (R(2)=0.86; P<0.0001) and total n-3 PUFA (R(2)=0.77; P<0.0001). IGF-1 concentrations increased on all diets and were greatest at the highest level of n-3 PUFA supplementation (P<0.05).

Effect of dietary enrichment with either n-3 or n-6 fatty acids on systemic metabolite and hormone concentration and ovarian function in heifers.

The objective of this experiment was to examine the effects of dietary n-3 or n-6 fatty acid (FA) supplementation on blood FA, metabolite and hormone concentrations, follicle size and dynamics and corpus luteum (CL) size. Reproductively normal heifers (n = 24) were individually fed diets of chopped straw and concentrate containing either (i) no added lipid (CON; n = 8); (ii) 2% added fat as whole raw soya beans (WSB, n-6; n = 8); or (iii) 2% added fat as fish oil (FO, n-3; n = 8). Following oestrous cycle synchronisation, blood samples were collected at appropriate times and intervals for the measurement of hormones, FAs and metabolites. On days 15 and 16 of the cycle, animals were subjected to an intravenous oxytocin challenge and prostaglandin F2α (PGF2α) response, measured as venous concentrations of 13,14-dihydro-15-keto PGF2α (PGFM). Dry matter intake and average daily gain were similar among treatments (P > 0.05). Plasma concentration of linoleic acid was highest on WSB (P < 0.05), while eicosapentaenoic (EPA, n-3; P < 0.0001) and docosahexaenoic acid (DHA, n-3; P < 0.0001) were greatest in the FO group. Plasma concentrations of arachidonic acid were higher on FO (P < 0.05) compared with CON and WSB. Plasma triglyceride concentrations increased, while ß-hydroxybutyrate (BHBA) decreased with time on all diets (P < 0.05). There was a diet × time interaction (P < 0.01) for non-esterified fatty acid (NEFA) concentrations. Plasma cholesterol was higher on WSB and FO (P < 0.01) compared with CON. Progesterone (P4) and oestradiol (E2) concentrations, as well as follicle growth rate and CL diameter were similar across diets (P > 0.05). There was a diet × day interaction for PGFM (P < 0.01). When corrected for systemic E2 : P4 ratio, day 15 concentrations of PGFM were higher in the WSB group at 15 and 30 min (P < 0.01) post oxytocin administration compared with CON and FO, which were similar (P > 0.05). Concentrations of PGFM on day 16 were similar for WSB and FO and were greater than CON at 15 (P < 0.01) and 45 min (P < 0.05) post oxytocin administration, and at 30 min for FO (P < 0.05). With the exception of PGFM, dietary lipid source did not affect the reproductive variables measured.

Cheese manufacture with milk with elevated conjugated linoleic acid levels caused by dietary manipulation.

The objective of this study was to assess the effect of dietary supplementation of cows on pasture with sunflower oil for conjugated linoleic acid (cis-9, trans-11 CLA) enrichment of milk, for the production of CLA-enriched cheese. A group of 40 autumn-calving dairy cows were assigned to either a control group (indoor feeding on grass silage ad libitum and 6 kg/d of a typical indoor concentrate) or an experimental group (on pasture, being fed 6 kg of a supplement containing 100 g/kg of sunflower oil per d). These diets were fed for 16 d, during which time milk was collected for pilot-scale hard cheese manufacture. The pasture-based diet with sunflower oil resulted in a significant effect on the milk fatty acid CLA content. The concentration of cis-9, trans-11 CLA in the milk produced from cows on this diet increased to 2.22 g/100 g of fatty acid methyl esters (FAME) after 14 d, compared with 0.46 g/100 g of FAME in milk produced on the control indoor diet. The content of cis-9, trans-11 CLA in the cheese manufactured from the indoor control milk was 0.78 g/100 g of FAME and that from the pasture-based sunflower oil milk was 1.93 g/100 g of FAME. The cheese was assessed during the ripening period and CLA concentrations were stable throughout the 6 mo of ripening. Other cheese variables (microbiology, composition, flavor, free AA) were monitored during the ripening period, and the cheese with the elevated CLA concentrations compared favorably with the control cheese. Thus, a pasture-based diet supplemented with an oil source rich in linoleic acid resulted in an enhanced CLA content of bovine milk fat, compared with an indoor grass silage-based diet.

Enumeration and identification of pediococci in powder-based products using selective media and rapid PFGE.

In this study, pediococci selective medium (PSM) was evaluated for the enumeration of Pediococcus acidilactici and Pediococcus pentosaceus from probiotic animal feed and silage inoculants. PSM is based on the complex basal medium MRS supplemented with cysteine hydrochloride, novobiocin, vancomycin, and nystatin. No significant change in electivity was observed when pediococci where recovered from culture or powder-based products following incubation at 37 degrees C under anaerobic conditions for 24 h. The medium was suitable for the enumeration of pediococci in samples also containing bacilli, bifidobacteria, enterococci, lactobacilli, lactococci, propionibacteria, streptococci, and yeast components. However, to inhibit Lactobacillus plantarum and Lactobacillus casei, ampicillin was added and the revised medium, termed PSM+A, was also considered to be suitably elective for pediococci recovered from powder. In addition, a rapid PFGE protocol is presented, which allows Pediococcus species and strain verification from colonies in less than 3 days.

Conjugated linoleic acid concentration in M. Longissimus dorsi from heifers offered sunflower oil-based concentrates and conserved forages.

Dietary inclusion of polyunsaturated fatty acid (PUFA)-rich plant oils is one approach to improving the fatty acid profile of ruminant meat and meat products from a human health perspective. Whole crop wheat silages represent a possible alternative forage to grass silage for beef production, however, they may adversely impact the fatty acid profile of ruminant muscle since grass silage is rich in C18:3n-3. The first objective of this experiment was to investigate the relationship between an increase in the dietary supply of C18:2n-6 from sunflower oil (SFO) and conjugated linoleic acid (CLA) concentration in the muscle tissue of beef cattle. The second objective was to investigate the effect of the basal forage type on the muscle fatty acid composition and its response to increasing inclusion of SFO. One hundred and five heifers were blocked according to initial bodyweight and assigned to one of seven silage treatments. The silage treatments were: (1) grass silage (GS), (2) whole crop wheat silage with 38% dry matter (DM) (W1), (3) GS and W1 at a ratio of 1:2 (DM basis) (W1GS) (4) GS and W1 at a ratio of 2:1 (DM basis) (GSW1), (5) whole crop wheat silage with 52% DM (W2), (6) GS and W2 at a ratio of 1:2 (DM basis) (W2GS), (7) GS and W2 at a ratio of 2:1 (DM basis) (GSW2). Within each silage treatment, 5 animals were assigned to one of three concentrate rations, differing in the content of SFO. The levels of inclusion of SFO in the concentrate were 0, 55, 110 g/kg concentrate. Inclusion of SFO in the diet led to an increase in the n-6:n-3 fatty acid ratio in muscle. In animals fed grass silage or mixed silages the n-6:n-3 ratio was lower in muscle compared with those fed whole crop wheat silages, with the exception of animals fed 55 g SFO/kg, for which feeding W1GS led to a higher ratio than W1. Other than the n-6:n-3 ratio there were no significant interactions between the effect of type of silage and the level of SFO on the concentration of fatty acids in intramuscular fat. Increasing the inclusion of SFO led to a linear increase in the CLAcis-9,trans-11 and PUFA concentration in intramuscular fat (P<0.001). This study confirmed the potential for modification, and improvement from a human health perspective, of the fatty acid composition of beef muscle by dietary manipulation.

The evaluation of a mupirocin-based selective medium for the enumeration of bifidobacteria from probiotic animal feed.

In this study, MRS medium supplemented with cysteine hydrochloride and mupirocin, termed Bifidobacterium selective medium (BSM) was found to be elective for bifidobacteria but inhibitory to a wide range of non-bifidobacteria strains commonly included in probiotic animal feed. Bacilli, lactobacilli, lactococci and streptococci failed to form colonies on BSM and enterococci, pediococci and propionibacteria formed colonies <0.5 mm in diameter. Bifidobacteria formed colonies >1 mm in size and could be readily distinguished. The addition of nystatin to BSM further inhibited Saccharomyces cerevisiae. BSM was successfully used to enumerate the bifidobacteria components, confirmed through fructose-6-phophate-phosphoketolase detection, present in two commercial probiotic feeds. The medium is recommended for the enumeration of bifidobacteria from animal feeds especially when not a numerically dominant component.

Conjugated linoleic acid and oxidative behaviour in cancer cells.

Convincing evidence from rodent models of carcinogenesis indicates that cis-9,trans-11 (c9t11) conjugated linoleic acid (CLA) is a potent naturally occurring anti-carcinogen in the human diet. CLA has been reported to alter the fatty acid composition of biological tissues in a manner that increases their oxidative stability. However, recent information suggests that an antioxidant role for CLA does not seem plausible. Given the knowledge that c9t11 CLA is present in a wide range of meat and dairy food products, our studies have begun to investigate mechanisms by which CLA-enriched milk fat exerts its anti-carcinogenic effects. An oxidative mechanism appears to be involved in its growth-suppressive effects, since supplementation of growth culture medium with CLA (17-71.5 microM) made breast cancer cells more susceptible to lipid peroxidation. Studies have indicated that cancer cells may become enriched in CLA during growth in culture. This may make intracellular lipids more susceptible to ordinary levels of oxidative stress, to the point of producing a cytotoxic effect.

Milk fat conjugated linoleic acid (CLA) inhibits growth of human mammary MCF-7 cancer cells.

The relationship between growth and the antioxidant enzyme defence system in human MCF-7 (breast) cancer cells treated with bovine milk fat enriched with conjugated linoleic acid (CLA) was studied. Milk enriched in CLA was obtained from cows on pasture supplemented with full fat rapeseeds and full fat soyabeans (1). Cell number decreased up to 90% (p < 0.05) and lipid peroxidation increased 15-fold (p < 0.05) following incubation of MCF-7 cells for 8 days with increasing levels of milk fat yielding CLA concentrations between 16.9 and 22.6 ppm. Growth suppression and prooxidant effects of milk fat CLA were independent of the variable composition of the milk fat samples, suggesting that CLA was the active ingredient in milk fat responsible for the cytotoxic effect. Mixtures containing isomers of CLA (c9, t11-, t10, c12-, c11, t13- and minor amounts of other isomers) and linoleic acid (LA) at similar concentrations to the milk fat samples were as effective at inhibiting growth and stimulating peroxidation of MCF-7 cells as the milk fatty acids. Incubation of the cells with the c9, t11 CLA isomer (20 ppm) or the mixture of CLA isomers (20 ppm) for 8 days resulted in a 60% decrease (p < 0.05) in viability compared with untreated controls and was significantly (p < 0.05) more effective than incubation with the t10, c12 CLA isomer (20 ppm), which caused only a 15% decrease in cell numbers under similar conditions. A 25% increase (p < 0.05) in cell proliferation occurred when LA (20 ppm) alone was incubated with MCF-7 cells for 8 days. 14C-CLA was preferentially incorporated into the phospholipid fraction of the MCF-7 cell lipids in a dose-dependent manner and CLA accumulated in cell membranes more efficiently when the cells were incubated in the presence of milk fat than the c9, t11 synthetic CLA isomer. Superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activities were induced in MCF-7 cells exposed to milk fat (containing 16.9-22.6 ppm CLA) over 8 days. The data indicate that milk fat triglyceride-bound CLA, consisting primarily of the c9, t11 isomer, was cytotoxic towards MCF-7 cells.

Elevation of conjugated cis-9, trans-11-octadecadienoic acid in bovine milk because of dietary supplementation.

Cows on pasture were fed full fat soybeans (toasted, flaked, and pelleted) or ground full fat rapeseeds to investigate effects on cis-9, trans-11-octadecadienoic acid in milk. Three herds of 16 cows each that were on pasture were fed 3.1 kg/d of unmolassed beet pulp (control), 3.0 kg/d of rapeseed concentrate, or 3.1 kg/d of a soybean supplement. The concentration of cis-9, trans-11-octadecadienoic acid in the milk of cows fed the rapeseed and soybean supplements was significantly higher than in the milk of cows fed the control diet during the feeding trial. Over the trial, the cis-9, trans-11-octadecadienoic acid concentration in the milk of individual cows varied from 6.8 to 25.7 mg/g of fat in the control herd, from 10.6 to 33.5 mg/g of fat in the herd fed the rapeseed concentrate, and from 8.8 to 30.5 mg/g of fat in the herd fed the soybean supplement. The concentration of cis-9, cis-12-octadecadienoic acid, the substrate for cis-9, trans-11-octadecadienoic acid synthesis in the rumen, was 4.9 g/100 g of fatty acid methyl esters in the milk fat of cows fed the soybean supplement, 2.5 g/100 g of fatty acid methyl esters in the milk fat of cows fed the rapeseed concentrate, and 2.3 g/100 g of fatty acid methyl esters in the milk fat of the control cows. Milk yield and milk constituent yields were not affected by supplementation of either full fat soybeans or rapeseeds compared with controls, but milk protein concentration was significantly reduced by both oilseed supplements.

Processing and expression of rat and human clotting factor-X-encoding cDNAs.

The cDNA encoding clotting factor X, which participates in the middle stage of the blood coagulation cascade was cloned from a rat liver cDNA library. Sequencing of the rat factor-X-encoding cDNA revealed that this vitamin-K-dependent protein has a dibasic Arg-Arg sequence at the propeptide cleavage site, as occurs in other vitamin-K-dependent proteins. Although the human and rat deduced amino acid sequences are remarkably similar (76% identical), they do significantly differ in that human factor-X contains a unique Thr-Arg sequence at the propeptide cleavage site [Fung et al., Proc. Natl. Acad. Sci. USA 82 (1985) 3591-3595], where a dibasic sequence would normally be expected. This specific site is the recognition motif for the endoprotease, furin, which is located in the Golgi apparatus. Both rat and human cDNAs expressed in Cos-1 cells resulted in secretion of a mixture of single- and two-chain forms of factor X. The two-chain forms were devoid of the propeptide and were produced at similar rates by the transfected cells. The efficient processing of human factor X, when compared to rat factor X, may indicate that an additional protease(s), which recognizes the Thr-Arg motif, may be involved in proteolytic processing of the human enzyme.

Effects of caffeine consumption on delayed conception.

The authors examined the effects of caffeine consumption on waiting time to conception in the Reproductive Health Study, a retrospective study of 1,430 non-contracepting, parous women interviewed between July 1989 and June 1990 at Fishkill, New York, and Burlington, Vermont. Information was obtained on 2,501 pregnancies since 1980. Women's reported consumption of caffeinated beverages during the first month of pregnancy was used to estimate daily caffeine intake, which was categorized as none, 1-150, 151-300, and > or = 301 mg. Information on delayed conception was analyzed as a dichotomous variable (< or = 12 months delay vs. > 12 months delay), and the per cycle probability of conception (fecundability) was estimated using waiting time to conception as a continuous variable. Odds ratios of delayed conception and fecundability ratios adjusted for age, parity, smoking, last contraceptive used, infertility history, and race, were estimated by logistic regression and Cox proportional hazard models, respectively. Women who did not smoke and who consumed no caffeine were used as a reference group. The adjusted odds ratio of delayed conception for more than one year was not increased among women who consumed < or = 300 mg of caffeine daily. However, the odds ratio (OR) was 2.65 (95% confidence interval (CI) 1.38-5.07) among nonsmokers who consumed > or = 301 mg of caffeine daily. Although smoking per se was associated with a significant increased risk of delayed conception (OR = 1.77, 95% CI 1.33-2.37), no effect of high caffeine consumption was observed among women who smoked. Fecundability was reduced among nonsmokers who consumed more than 300 mg caffeine daily (fecundability ratio = 0.74, 95% CI 0.59-0.92). Smoking reduced the fecundability ratio, but the authors observed no effect of caffeine consumption on fecundability among women who smoked. Other studies provide biologic plausibility for these findings. The authors conclude that high levels of caffeine consumption may result in delayed conception among women who do not smoke cigarettes.