Effects of contrasting forage diets on phosphorus utilisation in lactating dairy cows

The effects of different forage mixtures on duodenal flow and faecal output of phosphorus (P) were measured in lactating dairy cows in two experiments. The forages comprised grass silage (GS) alone or mixtures of GS and urea-treated whole crop wheat (WCW). Replacement of GS by high levels of WCW resulted in a significant decrease in total P (TP), water-soluble P (WSP) and acid-soluble P (ASP) intakes, but increased phytate P (PP) and acid-insoluble P (AIP) intakes. Duodenal flows of all P fractions were unaffected by dietary treatments. However, the amounts of all fractions flowing to the intestine were much higher than the amounts consumed-with the exception of AIP, which was unchanged, and PP, which was considerably reduced. Diets did not significantly affect faecal outputs of TP, ASP, PP and AIP; however, faecal outputs of WSP were significantly higher on WCW than GS diets. Inclusion of WCW significantly decreased TP and WSP availabilities in the total tract but did not affect PP and AIP availabilities. A new fraction of P, which was not present in the feeds, was found in significant amounts in the intestines and proved to be soluble in dilute acid but insoluble in water. Estimated annual excretions for a herd of 100 cows ranged from 1550 to 1721 kg for total P of which 337-786 kg was WSP. The results suggest that GS based diets deposit more P in the environment. However, the potential to cause P pollution depends not only on the quantity but also on the nature of faecal P and on soil parameters. © 2004 Elsevier B.V. All rights reserved.

The changing structure of diets in the European Union in relation to healthy eating guidelines

Objective: Our objective in this paper is to assess diets in the European Union (EU) in relation to the recommendations of the recent World Health Organization/Food and Agriculture Organization expert consultation and to show how diets have changed between 1961 and 2001. Data and methods: Computations make use of FAOSTAT data on food availability at country level linked to a food composition database to convert foods to nutrients. We further explore the growing similarity of diets in the EU by making use of a consumption similarity index. The index provides a single number measure of dietary overlap between countries. Results: The data confirm the excessive consumption by almost all countries of saturated fats, cholesterol and sugars, and the convergence of nutrient intakes across the EU. Whereas in 1961 diets in several European countries were more similar to US diets than to those of other European countries, this is no longer the case; moreover, while EU diets have become more homogeneous, the EU as a whole and the USA have become less similar over time. Conclusions: Although the dominant cause of greater similarity in EU diets over the period studied is increased intakes in Mediterranean countries of saturated fats, cholesterol and sugar, also important are reductions in saturated fat and sugar in some Northern European countries. This suggests that healthy eating messages are finally having an impact on diets; a distinctly European diet may also be emerging.

Rates of production of acetate, propionate, and butyrate in the rumen of lactating dairy cows given normal and low-roughage diets

Five lactating dairy cows with a permanent cannula in the rumen were given ( kg DM/d) a normal diet (7.8 concentrates, 5.1 hay) or a low-roughage (LR) diet (11.5 concentrates, 1.2 hay) in two meals daily in a two-period crossover design. Milk fat (g/kg) was severely reduced on diet LR. To measure rates of production of individual volatile fatty acids (VFA) in the rumen, 0.5 mCi 1-C-14-acetic acid, 2-C-14-propionic acid, or 1-C-14-n-butyric acid were infused into the rumen for 22 h at intervals of 2 to 6 d; rumen samples were taken over the last 12 h. To measure rumen volume, we infused Cr-EDTA into the rumen continuously, and polyethylene glycol was injected 2 h before the morning feed. Results were very variable, so volumes measured by rumen emptying were used instead. Net production of propionic acid more than doubled on LR, but acetate and butyrate production was only numerically lower. Net production rates pooled across both diets were significantly related to concentrations for each VFA. Molar proportions of net production were only slightly higher than molar proportions of concentrations for acetate and propionate but were lower for butyrate. The net energy value (MJ/d) of production of the three VFA increased from 89.5 on normal to 109.1 on LR, equivalent to 55 and 64% of digestible energy, respectively. Fully interchanging, three-pool models of VFA C fluxes are presented. It is concluded that net production rates of VFA can be measured in non-steady states without the need to measure rumen volumes.

Long-term monounsaturated fatty acid diets reduce platelet aggregation in healthy young subjects

The aim of the present study was to compare the response of a range of atherogenic and thrombogenic risk markers to two dietary levels of saturated fatty acid (SFA) substitution with monounsaturated fatty acids (MUFA) in students living in a university hall of residence. Although the benefits of such diets have been reported for plasma lipoproteins in high-risk groups, more needs to be known about effects of more modest SFA-MUFA substitutions over the long term and in young healthy adults. In a parallel design over 16 weeks, fifty-one healthy young subjects were randomised to one of two diets: (1) a moderate-MUFA diet in which 16 g dietary SFA/100 g total fatty acids were substituted with MUFA (n 25); (2) a high-MUFA diet in which 33 g dietary SFA/100 g total fatty acids were substituted with MUFA (n 26). All subjects followed an 8-week run-in diet (reference diet), with a fatty acid composition close to the UK average values. There were no differences in plasma lipid responses between the two diets over 16 weeks of the study with similar reductions in total cholesterol (P<0.001) and LDL-cholesterol (P<0.01) in both groups; a small but significant reduction in HDL-cholesterol was also observed in both groups (P<0.01). Platelet responses to ADP (P<0.01) and arachidonic acid (P<0.05) differed with time on the two diets; at 16 weeks, platelet aggregatory response to ADP was significantly lower on the high-MUFA than the moderate-MUFA (P<0.01) diet; ADP responses were also significantly lower within this group at 8 (P< 0.05) and 16 (P< 0.01) weeks compared with baseline. There were no differences in fasting factor VII activity (factors VIII and VIIag), fibrinogen concentration or tissue-type plasminogen activator activity between the diets. There were no differences in postprandial factor VIII responses to a standard meal (area under the curve) between the diets after 16 weeks, but postprandial factor VIII response was lower than on the high-MUFA diet compared with baseline (P<0.01). In conclusion, a high-MUFA diet sustains potentially beneficial effects on platelet aggregation and postprandial activation of factor VII. Moderate or high substitution of MUFA for SFA achieves similar reductions in fasting blood lipids in young healthy subjects.

Comparison of heat-treated rapeseed expeller and solvent-extracted soya-bean meal as protein supplements for dairy cows given grass silage-based diets

Sixteen early to mid lactation Finnish Ayrshire dairy cows were used in a cyclic change-over experiment with four 21-day experimental periods and a 4 5 2 factorial arrangement of treatments to evaluate the effects of heat-treated rapeseed expeller and solvent-extracted soya-bean meal protein supplements on animal performance. Dietary treatments consisted of grass silage offered ad libitum supplemented with a fixed amount of a cereal based concentrate (10 kg/day on a fresh weight basis) containing 120, 150, 180 or 210 g crude protein (CP) per kg dry matter (DM). Concentrate CP content was manipulated by replacement of basal ingredients (g/kg) with either rapeseed expeller (R; 120, 240 and 360) or soya-bean meal (S; 80, 160 and 240). Increases in concentrate CP stimulated linear increases (P < 0.05) in silage intake (mean 22.5 and 23.8 g DM per g/kg increase in dietary CP content, for R and S, respectively) and milk production. Concentrate inclusion of rapeseed expeller elicited higher (P < 0.01) milk yield and milk protein output responses (mean 108 and 3.71 g/day per g/kg DM increase in dietary CP content) than soya-bean meal (corresponding values 62 and 2.57). Improvements in the apparent utilization of dietary nitrogen for milk protein synthesis (mean 0.282 and 0.274, for R and S, respectively) were associated with higher (P < 0.05) plasma concentrations of histidine, branched-chain, essential and total amino acids (35, 482, 902 and 2240 and 26, 410, 800 and 2119 mu mol/l, respectively) and lower (P < 0.01) concentrations of urea (corresponding values 4.11 and 4.52 mmol/l). Heat-treated rapeseed expeller proved to be a more effective protein supplement than solvent-extracted soya-bean meal for cows offered grass silage-based diets.

Profiling of composition and metabolic activities of the colonic microflora of growing pigs fed diets supplemented with prebiotic oligosaccharides

It is evident that quantitative information on different microbial groups and their contribution in terms of activity in the gastrointestinal (GI) tract of humans and animals is required in order to formulate functional diets targeting improved gut function and host health. In this work, quantitative information on levels and spatial distributions of Bacteroides spp, Eubacterium spp, Clostridium spp, Escherichia coli, Bifidobacterium spp and Lactobacillus/Enterococcus spp. along the porcine large intestine was investigated using 16S rRNA targeted probes and fluorescent in situ hybridisation (FISH). Caecum, ascending colon (AC) and rectum luminal digesta from three groups of individually housed growing pigs fed either a corn-soybean basal diet (CON diet) or a prebiotic diet containing 10 g/kg oligofructose (FOS diet) or trans-galactooligosaccharides (TOS diet) at the expense of cornstarch were analysed. DAPI staining was used to enumerate total number of cells in the samples. Populations of total cells, Bacteroides, Eubacterium, Clostridium and Bifidobacterium, declined significantly (P < 0.05) from caecum to rectum, and were not affected by dietary treatments. Populations of Lactobacillus/ Enterococcus and E coli did not differ throughout the large intestine. The relative percent (%) contribution of each bacterial group to the total cell count did not differ between caecum and rectum, with the exception of Eubacterium that was higher in the AC digesta. FISH analysis showed that the sum of all bacterial groups made up a small percentage of the total cells, which was 12.4%, 21.8% and 10.3% in caecum, AC and rectum, respectively. This supports the view that in swine, the diversity of GI microflora might be higher compared to other species. In terms of microflora metabolic activity, the substantially higher numerical trends seen in FOS and TOS treatments regarding total volatile fatty acid, acetate concentrations and glycolytic activities, it could be postulated that FOS and TOS promoted saccharolytic activities in the porcine colon. (c) 2006 Elsevier Ltd. All rights reserved.

A comparison of the aroma volatiles and fatty acid compositions of grilled beef muscle from Aberdeen Angus and Holstein-Friesian steers fed diets based on silage or concentrates

This paper compares the volatile compound and fatty acid compositions of grilled beef from Aberdeen Angus and Holstein-Friesian steers slaughtered at 14 months, each breed fed from 6 months on either cereal-based concentrates or grass silage. Linoleic acid levels were higher in the muscle of concentrates-fed animals, which in the cooked meat resulted in increased levels of several compounds formed from linoleic acid decomposition. Levels of alpha-linolenic acid, and hence some volatile compounds derived from this fatty acid, were higher in the meat from the silage-fed steers. 1-Octen-3-ol, hexanal, 2-pentylfuran, trimethylamine, cis- and trans-2-octene and 4,5-dimethyl-2-pentyl-3-oxazoline were over 3 times higher in the steaks from the concentrates-fed steers, while grass-derived 1-phytene was present at much higher levels in the beef from the silage-fed steers. Only slight effects of breed were observed. (C) 2004 Elsevier Ltd. All rights reserved.

Effects of vitamin E and fish oil inclusion in broiler diets on meat fatty acid composition and on the flavour of a composite sample of breast meat

BACKGROUND: Enriching poultry meat with long-chain n-3 polyunsaturated fatty acids (LC n-3 PUFA) can increase low population intakes of LC n-3 PUFA, but fishy taints can spoil reheated meat. This experiment determined the effect of different amounts of LC n-3 PUFA and vitamin E in the broiler diet on the fatty acid composition and sensory characteristics of the breast meat. Ross 308 broilers (120) were randomly allocated to one of five treatments from 21 to 42 days of age. Diets contained (g kg−1) 0, 9 or 18 LC n-3 PUFA (0LC, 9LC, 18LC), and 100, 150 or 200 mg LD--tocopherol acetate kg−1 (E). The five diets were 0LC100E, 9LC100E, 18LC100E, 18LC150E, 18LC200E, with four pens per diet, except 18LC100E (eight pens). Breast meat was analysed for fatty acids (uncooked) and sensory analysis by R-index (reheated). RESULTS: LC n-3 PUFA content (mg kg−1 meat) was 514 (0LC100E) and 2236 (9LC and 18LC). Compared with 0LC100E, meat from 18LC100E and 18LC150E tasted significantly different, while 23% of panellists detected fishy taints in 9LC100E and 18LC200E. CONCLUSION: Chicken meat can be enriched with nutritionally meaningful amounts of LC n-3 PUFA, but > 100 mg dl--tocopherol acetate kg−1 broiler diet is needed to protect reheated meat from oxidative deterioration. Copyright © 2010 Society of Chemical Industry

Antioxidant activity of selected phenols and herbs used in diets for medical conditions.

The antioxidant capacity of some herbs used in dietology practice was determined by the DPPH free radical method, which was calibrated with ascorbic acid. Partially hydrophilic phenolic compounds are the most active compounds in plants, and therefore water was used as the extraction agent. Besides antioxidant capacity, the content of total phenolic compounds was also measured and a strong correlation between these two variables was found. The extracts of lemon balm (Melissa officinalis L.), peppermint (Mentha x piperita L.), oregano (Origanum vulgare L.), Greek oregano (Origanum heracleoticum L.), sage (Salvia officinalis L.) and winter savory (Satureja montana L.) showed very significant activity. It was comparable with the activity of green tea in the case of oregano and peppermint. Lower activity was observed in the case of rosemary (Rosmarinus officinalis L.), marjoram (Majorana hortensis), hyssop (Hyssopus officinalis L.), sweet basil (Ocimum basilicum), and lovage (Levisticum officinale Koch.). The inhibitory activity of the herb extracts was monitored also during the autooxidation of lard. Very high antioxidant capacity was observed mainly in sage samples, but also in marjoram and Greek oregano. The extracts of peppermint, oregano, rosemary, winter savory, lemon balm and hyssop showed middle activity comparable to that of alpha-tocopherol. The antioxidant capacity of sweet basil and lovage was insignificant.

Effects of ammonia treatment and undegradable protein supplementation on nutrient digestion of sheep fed on wheat straw based diets.

A study was conducted to investigate the effects of wheat straw ammonisation and supplementation with a rumen undegradable protein (UDP) source on nutrient digestion and nitrogen balance by lambs while diets were supplemented with kibbled carob pods as energy source. Ammonisation increased the crude protein content of wheat straw by nearly 100% and decreased the contents of neutral detergent fibre and acid detergent fibre by 7% and 1.7% respectively. Treating the straw with ammonia resulted in significant (P<0.01) increase in nitrogen (N) intake and intakes of organic matter (OM) and dry matter (DM) tended toward significance (P<0.1). The UDP source had no effect (P>0.05) on DM and OM intakes but resulted in an increase (P<0.05) of N intakes. Both, ammonization and UDP supplementation increased (P<0.01) the DM, OM and N digestibility. In conclusion, the results of this study suggest that ammonisation and UDP supplementation is a practical dietary manipulation option to improve the nutritional status of ruminants fed on roughage-based diets.

Effect of linseed oil and fish oil alone or as an equal mixture of ruminal fatty acid metabolism in growing steers fed maize silage-based diets

Based on the potential benefits to human health there is interest in increasing 18:3n-3, 20:5n-3, 22:6n-6, and cis-9,trans-11 conjugated linoleic acid (CLA) in ruminant foods. Four Aberdeen Angus steers (406 ± 8.2 kg BW) fitted with rumen and duodenal cannulae were used in a 4 x 4 Latin square experiment with 21 d periods to examine the potential of fish oil (FO) and linseed oil (LO) in the diet to increase ruminal outflow of trans-11 18:1 and total n-3 polyunsaturated fatty acids (PUFA) in growing cattle. Treatments consisted of a control diet (60:40; forage:concentrate ratio, on a DM basis, respectively) based on maize silage, or the same basal ration containing 30 g/kg DM of FO, LO or a mixture (1:1, w/w) of FO and LO (LFO). Diets were offered as total mixed rations and fed at a rate of 85 g DM/kg BW0.75/d. Oils had no effect (P = 0.52) on DM intake. Linseed oil had no effect (P > 0.05) on ruminal pH or VFA concentrations, while FO shifted rumen fermentation towards propionate at the expense of acetate. Compared with the control, LO increased (P < 0.05) 18:0, cis 18:1 (Δ9, 12-15), trans 18:1 (Δ4-9, 11-16), trans 18:2, geometric isomers of ∆9,11, ∆11,13, and ∆13,15 CLA, trans-8,cis-10 CLA, trans-10,trans-12 CLA, trans-12,trans-14 CLA, and 18:3n-3 flow at the duodenum. Inclusion of FO in the diet resulted in higher (P < 0.05) flows of cis-9 16:1, trans 16:1 (Δ6-13), cis 18:1 (Δ9, 11, and 13), trans 18:1 (Δ6-15), trans 18:2, 20:5n-3, 22:5n-3, and 22:6n-3, and lowered (P < 0.001) 18:0 at the duodenum relative to the control. For most fatty acids at the duodenum responses to LFO were intermediate of FO and LO. However, LFO resulted in higher (P = 0.04) flows of total trans 18:1 than LO and increased (P < 0.01) trans-6 16:1 and trans-12 18:1 at the duodenum compared with FO or LO. Biohydrogenation of cis-9 18:1 and 18:2n-6 in the rumen was independent of treatment, but both FO and LO increased (P < 0.001) the extent of 18:3n-3 biohydrogenation compared with the control. Ruminal 18:3n-3 biohydrogenation was higher (P < 0.001) for LO and LFO than FO, while biohydrogenation of 20:5n-3 and 22:6n-3 in the rumen was marginally lower (P = 0.05) for LFO than FO. In conclusion, LO and FO at 30 g/kg DM altered the biohydrogenation of unsaturated fatty acids in the rumen causing an increase in the flow of specific intermediates at the duodenum, but the potential of these oils fed alone or as a mixture to increase n-3 PUFA at the duodenum in cattle appears limited.