Potential cost and environmental impact of feeding high-oil corn to poultry in Brazil

The objective of the study was to evaluate the cost and environmental impact of replacing traditional corn, which is the main ingredient in poultry diets, with a high-oil corn (HOC) variety. Using linear programming, diets were formulated with either traditional corn or HOC. The results indicate that HOC-based diets cost up to $11.38/tonne less than traditional corn-based diets. Using HOC rather than traditional corn in diets has the potential to reduce the annual nitrogen excreted to the environment from broilers and broiler breeders in Brazil by 6.44 Mtonnes. In addition, there is the potential to reduce P excretion by 4.52 Mtonnes/yr, because the need to supplement diets with inorganic P sources, such as dicalcium phosphate, is much lower with HOC-based diets. We estimate that 28.5 Mtonnes of dicalcium phosphate can be saved annually using HOC in Brazilian poultry diets. The literature suggests that replacing traditional corn with HOC does not affect bird metabolism, while positive impacts on growth rate have been recorded. Therefore, substituting traditional corn with HOC has cost and environmental benefits for the Brazilian poultry industry without compromising productivity.

Detection of pressed hazelnut oil in virgin olive oil by analysis of polar components: improvement and validation of the method

An improved method for the detection of pressed hazelnut oil in admixtures with virgin olive oil by analysis of polar components is described. The method. which is based on the SPE-based isolation of the polar fraction followed by RP-HPLC analysis with UV detection. is able to detect virgin olive oil adulterated with pressed hazelnut oil at levels as low as 5% with accuracy (90.0 +/- 4.2% recovery of internal standard), good reproducibility (4.7% RSD) and linearity (R-2: 0.9982 over the 5-40% adulteration range). An international ring-test of the developed method highlighted its capability as 80% of the samples were, on average, correctly identified despite the fact that no training samples were provided to the participating laboratories. However, the large variability in marker components among the pressed hazelnut oils examined prevents the use of the method for quantification of the level of adulteration. (C) 2003 Elsevier Ltd. All rights reserved.

Effect of forage type and proportion of concentrate in the diet on milk fatty acid composition in cows given sunflower oil and fish oil

Based on the potential benefits of cis-9, trans- 11 conjugated linoleic acid (CLA) for human health there is a need to develop effective strategies for enhancing milk fat CLA concentrations. In this experiment, the effect of forage type and level of concentrate in the diet on milk fatty acid composition was examined in cows given a mixture of fish oil and sunflower oil. Four late lactation Holstein-British Friesian cows were used in a 4 x 4 Latin-square experiment with a 2 x 2 factorial arrangement of treatments and 21-day experimental periods. Treatments consisted of grass (G) or maize (M) silage supplemented with low (L) or high (H) levels of concentrates (65: 35 and 35: 65; forage: concentrate ratio, on a dry matter (DM) basis, respectively) offered as a total mixed ration at a restricted level of intake (20 kg DM per day). Lipid supplements (30 g/kg DM) containing fish oil and sunflower oil (2: 3 w/w) were offered during the last 14 days of each experimental period. Treatments had no effect on total DM intake, milk yield, milk constituent output or milk fat content, but milk protein concentrations were lower (P<0.05) for G than M diets (mean 43.0 and 47.3 g/kg, respectively). Compared with grass silage, milk fat contained higher (P<0.05) amounts Of C-12: 0, C-14: 0, trans C-18:1 and long chain >= C20 (n-3) polyunsaturated fatty acids (PUFA) and lower (P<0.05) levels Of C-18:0 and trans C-18:2 when maize silage was offered. Increases in the proportion of concentrate in the diet elevated (P<0.05) C-18:2 (n-6) and long chain >= C20 (n-3) PUFA content, but reduced (P<0.05) the amount Of C-18:3 (n-3). Concentrations of trans-11 C-18:1 in milk were independent of forage type, but tended (P<0.10) to be lower for high concentrate diets (mean 7.2 and 4.0 g/100 g fatty acids, for L and H respectively). Concentrations of trans-10 C-18:1 were higher (P<0.05) in milk from maize compared with grass silage (mean 10.3 and 4.1 g/100 g fatty acids, respectively) and increased in response to high levels of concentrates in the diet (mean 4.1 and 10.3 g/100 g fatty acids, for L and H, respectively). Forage type had no effect (P>0.05) on total milk conjugated linoleic acid (CLA) (2.7 and 2.8 g/100 g fatty acids, for M and G, respectively) or cis-9, trans-11 CLA content (2.2 and 2.4 g/100 g fatty acids). Feeding high concentrate diets tended (P<0.10) to decrease total CLA (3.3 and 2.2 g/100 g fatty acids, for L and H, respectively) and cis-9, trans-11 CLA (2.9 and 1/7 g/100 g fatty acids) concentrations and increase milk trans-9, cis-11 CLA and trans-10, cis-12 CLA content. In conclusion, the basal diet is an important determinant of milk fatty acid composition when a supplement of fish oil and sunflower oil is given.

Effect of dietary fish oil on biohydrogenation of fatty acids and milk fatty acid content in cows

Mechanisms underlying milk fat conjugated linoleic acid (CLA) responses to supplements of fish oil were investigated using five lactating cows each fitted with a rumen cannula in a simple experiment consisting of two consecutive 14-day experimental periods. During the first period cows were offered 18 kg dry matter (DM) per day of a basal (B) diet formulated from grass silage and a cereal based-concentrate (0.6 : 0.4; forage : concentrate ratio, on a DM basis) followed by the same diet supplemented with 250 g fish oil per day (FO) in the second period. The flow of non-esterified fatty acids leaving the rumen was measured using the omasal sampling technique in combination with a triple indigestible marker method based on Li-Co-EDTA, Yb-acetate and Cr-mordanted straw. Fish oil decreased DM intake and milk yield, but had no effect on milk constituent content. Milk fat trans-11C(18:1), total trans-C-18:1, cis-9 trans-11 CLA, total CLA, C-18 :2 (n- 6) and total C-18:2 content were increased in response to fish oil from 1.80, 4.51, 0.39, 0. 56, 0.90 and 1.41 to 9.39, 14.39, 1.66, 1.85, 1.25 and 4.00 g/100 g total fatty acids, respectively. Increases in the cis-9, trans-11 isomer accounted for proportionately 0.89 of the CLA response to fish oil. Furthermore, fish oil decreased the flow of C-18:0 (283 and 47 g/day for B and FO, respectively) and increased that of trans-C-18:1 fatty acids entering the omasal canal (38 and 182 g/day). Omasal flows of trans-C-18:1 acids with double bonds in positions from delta-4 to -15 inclusive were enhanced, but the effects were isomer dependent and primarily associated with an increase in trans-11C(18:1) leaving the rumen (17.1 and 121.1 g/day for B and FO, respectively). Fish oil had no effect on total (4.36 and 3.50 g/day) or cis-9, trans-11 CLA (2.86 and 2.08 g/day) entering the omasal canal. Flows of cis-9, trans-11 CLA were lower than the secretion of this isomer in milk. Comparison with the transfer of the trans-9, trans-11 isomer synthesized in the rumen suggested that proportionately 0.66 and 0.97 of cis-9, trans-11 CLA was derived from endogenous conversion of trans-11 C-18:1 in the mammary gland for B and FO, respectively. It is concluded that fish oil enhances milk fat cis-9, trans-11 CLA content in response to increased supply of trans-11 C-18:1 that arises from an inhibition of trans C-18:1 reduction in the rumen.

Effects of enhanced consumption of fruit and vegetables on plasma antioxidant status and oxidative resistance of LDL in smokers supplemented with fish oil

Objective: To determine whether consumption of five portions of fruit and vegetables per day reduces the enhancement of oxidative stress induced by consumption of fish oil. Subjects: A total of 18 free-living healthy smoking volunteers, aged 18-63 y, were recruited by posters and e-mail in The University of Reading, and by leaflets in local shops. Design: A prospective study. Setting: Hugh Sinclair Unit of Human Nutrition, School of Food Biosciences, The University of Reading, Whiteknights PO Box 226, Reading RG6 6AP, UK. Intervention: All subjects consumed a daily supplement of 4 x 1 g fish oil capsules for 9 weeks. After 3 weeks, they consumed an additional five portions of fruits and vegetables per day, and then they returned to their normal diet for the last 3 weeks of the study. Fasting blood samples were taken at the ends of weeks 0, 3, 6 and 9. Results: The plasma concentrations of ascorbic acid, lutein, beta-cryptoxanthin, alpha-carotene and beta-carotene all significantly increased when fruit and vegetable intake was enhanced (P<0.05). Plasma concentrations of α-tocopherol, retinol and uric acid did not change significantly during the period of increased fruit and vegetable consumption. Plasma oxidative stability, assessed by the oxygen radical absorbance capacity (ORAC) assay, also increased from weeks 3-6 (P<0.001) but not in association with increases in measured antioxidants. Lag phase before oxidation of low-density lipoprotein (LDL) significantly decreased in the first 3 weeks of the study, reflecting the incorporation of EPA and DHA into LDL (P<0.0001). Subsequent enhanced fruit and vegetable consumption significantly reduced the susceptibility of LDL to oxidation (P<0.005). Conclusion: Fish oil reduced the oxidative stability of plasma and LDL, but the effects were partially offset by the increased consumption of fruit and vegetables.

Changes in phenolic composition and antioxidant activity of virgin olive oil during frying

The concentration of hydroxytyrosol (3,4-DHPEA) and its secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEA-EA) in virgin olive oil decreased rapidly when the oil was repeatedly used for preparing french fries in deep-fat frying operations. At the end of the first frying process (10 min at 180 degreesC), the concentration of the dihydroxyphenol components was reduced to 50-60% of the original value, and after six frying operations only about 10% of the initial components remained. However, tyrosol (p-HPEA) and its derivatives (p-HPEA-EDA and p-HPEA-EA) in the oil were much more stable during 12 frying operations. The reduction in their original concentration was much smaller than that for hydroxytyrosol and its derivatives and showed a roughly linear relationship with the number of frying operations. The antioxidant activity of the phenolic extract measured using the DPPH test rapidly diminished during the first six frying processes, from a total antioxidant activity higher than 740,mumol of Trolox/kg down to less than 250 mumol/kg. On the other hand, the concentration of polar compounds, oxidized triacylglycerol monomers (oxTGs), dimeric TGs, and polymerized TGs rapidly increased from the sixth frying operation onward, when the antioxidant activity of the phenolic extract was very low, and as a consequence the oil was much more susceptible to oxidation. The loss of antioxidant activity in the phenolic fraction due to deep-fat frying was confirmed by the storage oil and oil-in-water emulsions containing added extracts from olive oil used for 12 frying operations.