The effect of different concentrations of linseed oil or fish oil in the maternal diet on the fatty acid composition and oxidative status of sows and piglets.

N-3 polyunsaturated fatty acids (PUFA) are essential for foetal development. Hence, including n-3 PUFA in the sow diet can be beneficial for reproduction. Both the amount and form (precursor fatty acids vs. long chain PUFA) of supplementation are important in this respect. Furthermore, including n-3 PUFA in the diet can have negative effects, such as decreased arachidonic acid (ARA) concentration and increased oxidative stress. This study aimed to compare the efficacy to increase eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) concentrations in the piglet, when different concentrations of linseed oil (LO, source of precursor α-linolenic acid) or fish oil (FO, source of EPA and DHA) were included in the maternal diet. Sows were fed a palm oil diet or a diet including 0.5% or 2% LO or FO from day 45 of gestation until weaning. Linoleic acid (LA) was kept constant in the diets to prevent a decrease in ARA, and all diets were supplemented with α-tocopherol acetate (150 mg/kg) and organic selenium (0.4 mg/kg) to prevent oxidative stress. Feeding 0.5% LO or 0.5% FO to the sows resulted in comparable EPA concentrations in the 5-day old piglet liver, but both diets resulted in lower EPA concentrations than when 2% LO was fed. The highest EPA concentration was obtained when 2% FO was fed. The DHA level in the piglet liver could only be increased when FO, but not LO, was fed to the sows. The 2% FO diet had no advantage over the 0.5% FO diet to increase DHA in the piglet. Despite the constant LA concentration in the sow diet, a decrease in ARA could not be avoided when LO or FO were included in the diet. Feeding 2% FO to the sows increased the malondialdehyde concentration (marker for lipid peroxidation) in sow plasma, but not in piglets.

Linoleate isomerase activity occurs in lactic acid bacteria strains and is affected by pH and temperature.

AIMS: To investigate the ability of lactic acid bacteria (LAB) to convert linoleic acid (LA) and α-linolenic acid (α-LNA) to conjugated linoleic acid (CLA) and conjugated linolenic acid (CLNA), respectively. To assess pH and temperature influences on CLA and CLNA production by Lactobacillus sakei LMG 13558. METHODS AND RESULTS: A screening of 48 LAB yielded one Lactobacillus curvatus, five Lactobacillus plantarum and four Lact. sakei strains displaying linoleate isomerase (LAI) activity. CLNA conversion percentages varied largely (1-60%). CLA conversion, occurring in three strains, was lower (2-5%). The LAI gene sequences of the ten LAI-positive strains shared 75-99% identity with the LAI gene sequence of a Lact. plantarum AS1.555. At pH 6.2, CLA and CLNA production by Lact. sakei LMG 13558 was higher at 30°C than at 20 and 25°C. At pH 5.5 (30°C) or 37°C (pH 6.2), LA was not converted and α-LNA only slightly converted. CONCLUSIONS: LAB show strain-dependent LAI activity. Production of CLA and CLNA is affected by pH and temperature, as shown for Lact. sakei LMG 13558. SIGNIFICANCE AND IMPACT OF THE STUDY: Several LAB produce CLA and/or CLNA, as shown for Lact. sakei and Lact. curvatus for the first time. These findings offer potential for the manufacturing of fermented functional foods.

Effect of dietary antioxidant supplementation on the oxidative status of plasma in broilers.

In this study, the effect of dietary antioxidants on the plasma oxidative status of growing birds fed a diet rich in polyunsaturated fatty acids was investigated. One-day-old broilers were fed for 42 days a diet containing 4% linseed oil and supplemented with single plant extracts rich in antioxidants (natural tocopherols, rosemary, grape seed, green tea, tomato) or a combination of some of these plant extracts, in two different total doses (100 and 200 mg product/kg feed). A diet with synthetic antioxidants with and without α-tocopheryl acetate (200 mg/kg feed) were also included. The plasma oxidative status was evaluated measuring the ferric reducing ability of plasma (FRAP), the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. Lipid peroxidation was measured by thiobarbituric acid-reactive substances (TBARS). No significant effect of the dietary treatments was observed for FRAP as well as for TBARS. However, diet affected GSH-Px activity (p = 0.002) and a trend for an effect on SOD activity was observed (p=0.084). A higher GSH-Px activity was found for 200 mg/kg tomato extract and natural α-tocopherol in relation to the corresponding 100 mg/kg treatment, and the lowest GSH-Px activity was measured for the synthetic antioxidants treatment. The lowest and highest SOD activity were found for the 200. and 100 mg/kg treatment with tomato extract respectively. In conclusion, the oxidative status and lipid oxidation of plasma in broilers was not affected by feeding natural antioxidant extracts at the doses in the present study, but some changes in antioxidant enzyme activities were observed, of which the implication remains to be elucidated.

Effect of diet, sex and age on fatty acid metabolism in broiler chickens: SFA and MUFA.

The present study was conducted to evaluate the effect of different dietary lipid sources, age and sex on the SFA and MUFA metabolism in broiler chickens using a whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm; soyabean oil, Soya; linseed oil, Lin; and fish oil, Fish) were added at 3 % to a basal diet containing 5 % Palm. Diets were fed to female and male chickens from day 1 to either day 21 or day 42 of age. The accumulation (percentage of net intake and ex novo production) of SFA and MUFA was significantly lower in broilers fed on Palm than in broilers fed on the other diets (85.7 v. 97.4 %). Conversely, beta-oxidation was significantly higher in Palm-fed birds than the average of the other dietary treatments (14.3 v. 2.6 %). On average, 33.1 % of total SFA and MUFA accumulated in the body were elongated, and 13.8 % were Delta-9 desaturated to longer chain or more unsaturated metabolites, with lower proportions being elongated and desaturated for the Palm and Fish diets than for the Soya and Lin diets. Total in vivo apparent elongase activity decreased exponentially in relation to the net intake of SFA and MUFA, while it increased with age. Total in vivo apparent Delta-9 desaturase activity was not significantly affected by dietary treatment or age. Total ex novo production and beta-oxidation of SFA and MUFA showed a negative and positive curvilinear relationship with net intake of SFA and MUFA, respectively. Sex had no effect on SFA and MUFA metabolism.

Effect of diet, sex and age on fatty acid metabolism in broiler chickens: n-3 and n-6 PUFA.

The PUFA metabolism in broiler chicken was studied through the whole body fatty acid balance method. Four dietary lipid sources (palm fat, Palm; soyabean oil, Soya; linseed oil, Lin; fish oil, Fish) were added at 3 % to a basal diet containing 5 % palm fat. Diets were fed to female and male birds from day 1 to either day 21 or day 42 of age. Birds fed the Lin diet showed a significantly higher 18 : 2n-6 accumulation compared with the other diets (85.2 v. 73.6 % of net intake), whereas diet did not affect 18 : 3n-3 accumulation (mean 63 % of net intake). Bioconversion of 18 : 2n-6 significantly decreased in the order Palm>Lin>Soya>Fish (4.7, 3.9, 3.4 and 1 % of net intake, respectively). The 18 : 3n-3 bioconversion on the Palm and Soya diets was similar and significantly higher than in broilers on the Lin diet (9.1 v. 5.8 % of net intake). The beta-oxidation of 18 : 2n-6 was significantly lower on the Lin diet than on the other diets (10.8 v. 23.3 % of net intake), whereas beta-oxidation of 18 : 3n-3 was significantly higher on the Fish diet than on the other diets (41.5 v. 27.3 % of net intake). Feeding fish oil suppressed apparent elongase and desaturase activity, whereas a higher dietary supply of 18 : 3n-3 and 18 : 2n-6 enhanced apparent elongation and desaturation activity on the PUFA involved in the n-3 and n-6 pathway, respectively. Accumulation of 18 : 2n-6 and 18 : 3n-3 increased and beta-oxidation decreased with age. Sex had a marginal effect on the PUFA metabolism.

Crystallization behavior of milk fat obtained from linseed-fed cows.

Milk with an increased content of unsaturated fatty acids was obtained by incorporating 60% of extruded linseed into the concentrate of cows. Two groups of Holstein cows (3 animals/group) were fed a concentrate (control or linseed enriched) together with the same roughage diet (ad libitum). After an adaptation period of 3 wk, evening and morning milk samples were collected every 7 d for 3 wk. Milk was decreamed and anhydrous milk fat (AMF) was isolated from the fat fraction by using the Bureau of Dairy Industries method. The objective of this study was to investigate if the crystallization mechanism of milk fat changed when the content of unsaturated fatty acids was increased. Therefore, the crystallization behavior of a milk fat enriched with unsaturated fatty acids was compared with that of a control milk fat. Nonisothermal crystallization was investigated with differential scanning calorimetry, and 1-step and 2-step isothermal crystallization behaviors were investigated using pulsed nuclear magnetic resonance, differential scanning calorimetry, and x-ray diffraction. A higher content of unsaturated fatty acids in AMF resulted in an increased proportion of low melting triglycerides. These triglycerides lowered the solid fat content profile, particularly at refrigerator temperatures. Furthermore, they induced some changes in the crystallization and melting behaviors of milk fat compared with a control AMF, although no fundamental changes in the crystallization mechanism could be revealed. Even though a lower melting point could be observed for milk fat with a higher content of unsaturated fatty acids, a similar degree of supercooling was needed to initiate crystallization, resulting in a shift in onset temperature of crystallization toward lower temperatures. In addition, slower crystallization kinetics were measured, such as a lower nucleation rate and longer induction times, although crystallization occurred in a similar polymorphic crystal lattice. During melting, a shift in offset temperature toward lower temperatures could be observed for the 3 melting fractions of AMF in addition to a higher proportion of low melting triglycerides. These results demonstrate that a higher content of unsaturated fatty acids has some effect on the crystallization behavior of milk fat. This knowledge could be used to produce dairy products of similar or superior quality compared with conventional products by intervening in the production process of dairy products.

Effects of diet, age and gender on the polyunsaturated fatty acid composition of broiler anatomical compartments.

1. The objective of this study was to investigate the effect of dietary fatty acid (FA) composition, age, and gender on the FA composition of different broiler anatomical compartments. Four dietary fat sources (palm fat, P; soybean oil, S; linseed oil, L; fish oil, F) were added to a wheat-soybean meal based diet at 30 g/kg in addition to 50 g/kg palm fat. Diets were fed separately to female and male birds from d 1 to either d 21 or d 42 of age. 2. The total FA content (mg/100 g tissue) and the FA composition (g/100 g FAME) was determined in 7 anatomical compartments (skinless thigh muscle, skinless breast muscle, liver, heart, brain, abdominal fat pad, and remainders plus carcase trimmings named Rest compartment). The FA profiles differed greatly among compartments and were strongly affected by diet. 3. The S diet resulted in a 2-3-fold increase of the proportion of C18:2n-6 and C20:4n-6 in all compartments compared to the other diets, except for brain. 4. The response in the proportion of C18:3n-3 following feeding the L diet was much greater, with 4-20-fold increases compared to the other diets, except again for brain. 5. In all compartments except brain, the L diet resulted in approximately a 2-fold increase in the proportion of C22:6n-3 compared to the P and S diets and smaller, but also significant, increases for C20:5n-3 and C22:5n-3. 6. The proportions of C20:5n-3, C22:5n-3 and C22:6n-3 were much higher on the F diet in all compartments, except for brain, compared to the P and S diets. The F diet resulted in higher proportions of C22:6n-3 than the proportions of C20:5n-3 and C22:5n-3 in breast and thigh meat, and liver, in contrast to the other diets. 7. Brain was less responsive than other tissues to changes in the dietary FA composition. The proportion of C22:6n-3 in brain was similar on the L and F diets. 8. The effect of gender on the FA composition of different anatomical compartments was marginal. The long-chain n-3 and n-6 PUFA in breast, liver, and brain decreased with age.

Effect of dietary rosemary and α-tocopheryl acetate on the oxidative stability of raw and cooked pork following oxidized linseed oil administration.

The effect of a 2% dietary administration to pigs of oxidized linseed oil (targeted level of 150mEq.O(2)/kg oil after heating at 50°C and exposure to air for 3-4 days following addition of 10ppm CuSO(4)), either or not in combination with antioxidants, on the oxidative stability of raw and cooked pork during illuminated chill storage was assessed. The antioxidant treatments were: 40ppm α-tocopheryl acetate, 40ppm rosemary extract, 40ppm rosemary extract+2ppm gallic acid, and 40ppm α-tocopheryl acetate+40ppm rosemary extract. A total of 20ppm of α-tocopheryl acetate (ATA) was added to all diets in order to meet the physiological requirement of the animals. The antioxidant treatments did not exert any effect on colour and protein oxidation. Lipid oxidation was only decreased by dietary ATA when comparing the ATA supplemented groups combined versus a control treatment group for raw but not for cooked meat. This was due to a higher content of α-tocopherol in the meat and subcutaneous fat. The lipid oxidation results suggested a lack of antioxidant effect for the rosemary extract. No evidence for a synergistic effect of the antioxidant combinations was observed.

Lipid and protein oxidation of broiler meat as influenced by dietary natural antioxidant supplementation.

Natural tocopherols (TC), rosemary (RO), green tea (GT), grape seed, and tomato extracts were supplemented in single and in combinations at total concentrations of 100 and 200 mg.kg(-1) of feed in a 4% linseed oil-containing diet to investigate the oxidative stability of broiler breast muscle. Supplementation with 300 mg.kg(-)1 of synthetic antioxidants alone and synthetic antioxidants with alpha-tocopheryl acetate at a concentration of 200 mg.kg(-1) (100 IU) feed was used as a control. Fresh patties were prepared and stored under light at 4 degrees C. After freezing for 8 mo and overnight thawing, 3 other patties were prepared and similarly stored under light at 4 degrees C. During display, samples were evaluated for oxidative stability measurements. For lipid oxidation, the treatment with synthetic antioxidants and 200 mg.kg(-1) of alpha-tocopheryl acetate yielded the lowest TBA reactive species (TBARS) values. For TC, grape seed, and tomato extracts, TBARS values for 100 mg.kg(-1) were higher (P < 0.05) than 200 mg.kg(-1) treatments, whereas no differences (P > 0.05) in TBARS values were observed for RO between 100 and 200 mg.kg(-1). In contrast, GT showed higher TBARS values at 200 mg.kg(-1). Administration of combinations of TC, RO, and GT did not reveal synergistic effects but confirmed the increase in TBARS values with increasing doses of GT. No differences (P > 0.05) among the different antioxidant treatments were detected for protein oxidation. The muscle alpha-tocopherol content linearly responded to the feed alpha-tocopherol content and thus there were no indications for a sparing effect on alpha-tocopherol from other antioxidant treatments. In summary, dietary natural antioxidant extracts were less effective than the treatment with synthetic antioxidants combined with alpha-tocopheryl acetate for protecting against oxidation, but there were marked differences between different natural antioxidant extracts.

Evaluation Of Mycotoxin Content In Soybean (Glycine max L.) Grown In Rwanda.

Soybean is a critical food and nutritional security crop in Rwanda. Promoted by the Rwandan National Agricultural Research System for both adults and as an infant weaning food, soybean is grown by approximately 40% of households. Soybean may be susceptible to the growth of mycotoxin-producing moulds; however, data has been contradictory. Mycotoxin contamination is a food and feed safety issue for grains and other field crops. This study aimed to determine the extent of mycotoxin contamination in soybean, and to assess people's awareness on mycotoxins. A farm-level survey was conducted in 2015 within three agro-ecological zones of Rwanda suitable for soybean production. Soybean samples were collected from farmers (n=300) who also completed questionnaires about pre-and post-harvest farm practices, and aflatoxin awareness. The concentration of total aflatoxin in individual soybean samples was tested by enzymelinked immunosorbent assay (ELISA) using a commercially-available kit. Other mycotoxins were analyzed using liquid chromatography-mass spectrometry (LCMS/MS) on 10 selected sub samples. Only 7.3% of the respondents were aware of aflatoxin contamination in foods, but farmers observed good postharvest practices including harvesting the crop when the pods were dry. Using enzyme-linked immunosorbent assay (ELISA), only one sample had a concentration (11 µg/kg) above the most stringent EU maximum permitted limit of 4 µg/kg. Multi-mycotoxins liquid chromatography-mass spectrometry (LC-MS/MS) results confirmed that soybeans had low or undetectable contamination; only one sample contained 13µg/kg of sterigmatocystine. The soybean samples from Rwanda obtained acceptably low mycotoxin levels. Taken together with other studies that showed that soybean is less contaminated by mycotoxins, these results demonstrate that soybean can be promoted as a nutritious and safe food. However, there is a general need for educating farmers on mycotoxin contamination in food and feed to ensure better standards are adhered to safeguard the health of the consumers regarding these fungal secondary metabolites.

Influence of dietary selenium and vitamin E on quality of veal.

Three groups of six calves each were fed a milk replacer and a starter concentrate for 15weeks. Calves of the first group received the basal diet containing selenium (Se) and vitamin E at 0.095-0.128mg and 30-33mg per kg of total solids, respectively. Calves of the second group received the basal diet supplemented with Se-enriched yeast to increase dietary Se concentration to 0.50mg/kg. The third group of calves received the latter diet supplemented with vitamin E to increase its concentration to 100mg/kg. There was no effect of diet on growth rate, digestibility of dry matter and Se, chemical composition of meat (M. Longissimus thoracis et lumborum), meat colour and fatty acid profile of meat lipids. The Se supplementation significantly increased Se concentration in muscle from 0.21 to 0.43mg/kg. The activity of glutathione peroxidase (GSH-Px) in muscle and liver tissue of Se-supplemented animals was increased by 56% and 67%, respectively, compared to the control. The combined supplementation of vitamin E and Se significantly improved the lipid stability of meat compared to the control diet, but not compared to the Se-supplemented diet. It can be concluded that dietary Se supplementation increases the concentration of Se and the GSH-Px activity in meat, but has limited potential for improving meat oxidative stability.

Effect of grazing pastures of different botanical composition on antioxidant enzyme activities and oxidative stability of lamb meat.

The aim of this work was to study the influence of different pastures (Intensive ryegrass, Botanically diverse and Leguminosa rich pastures) on the antioxidant status and oxidative stability of meat from lambs that had been exclusively grazing for three months. Lipid, colour and protein oxidation, α-tocopherol content and activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (Cat) and glutathione peroxidase (GSH-Px)) were measured in Longisimus thoracis et lumborum muscle samples taken 1 day after slaughter. Pasture type significantly affected protein oxidation and the activity of GSH-Px, but no significant differences were found for the α-tocopherol content, colour and lipid oxidation, and the activities of SOD and Cat. Grazing a Botanically diverse pasture induced significantly higher protein oxidation in meat, as measured by the free thiol and carbonyl contents, compared to a Leguminosa rich or Intensive ryegrass pasture (P<0.05). The GSH-Px activity was significantly higher in meat from lambs on the Leguminosa rich pasture compared to the other pasture groups (P<0.01).

Immunocompetence in organically fed finishing pigs: effect of corn cob mix.

Two consecutive experiments were performed to evaluate the effects on the immune response of corn cob mix (CCM) in an organic pig diet. The immunoglobulin (Ig) M, IgA and IgG responses against an intramuscularly injected model antigen, bovine thyroglobulin, were used as indicator. The experiments were performed in an organic barn with nine pens of four crossbred pigs (two barrows and two sows) from 45 kg to slaughter. In the first experiment, the organic concentrate was mixed with organic CCM-silage to obtain three concentrate: CCM ratios of 100:0, 80:20 and 60:40 (w:w). In the second experiment, three concentrates were produced to obtain diets with equal nutrient levels on a dry matter basis after 0%, 20% and 40% CCM inclusion. Higher inclusion rates of CCM in the ration were accompanied by lower thyroglobulin-specific IgG responses. These effects could not be attributed to one specific component of the CCM, such as fatty acid composition, although there was a degree of correlation with lower vitamin A concentrations. Mycotoxin concentrations were absent or minimal. The study indicated that dietary ingredient composition may affect immunocompetence.

Effect of dietary antioxidant and fatty acid supply on the oxidative stability of fresh and cooked pork.

The effect of dietary oil (linseed or soybean oil) and antioxidant treatment (α-tocopheryl acetate (AT; 40ppm) versus a cocktail (AOC; 200ppm): α-tocopheryl acetate+rosemary+citric acid+gallic acid) on colour, lipid and protein oxidation of fresh and processed pork was investigated. No effect of oil source on different parameters of oxidation was seen. No effect of antioxidant treatment on colour stability of fresh longissimus thoracis (LT) or cooked cured ham (CCH) was observed. For both antioxidant treatments, lipid oxidation in fresh LT and CCH was well controlled during display. However, lipid oxidation increased significantly in pre-frozen uncured cooked meat under aerobic conditions. No unambiguous effect of antioxidant treatment on protein oxidation was observed. There seemed to be no clear link between colour, protein and lipid oxidation. At the dose used in this study, no additional or synergistic effects of the extra components of the AOC on the different oxidation parameters was found.

Performance and meat quality of organically versus conventionally fed and housed pigs from weaning till slaughtering.

The effects of organic nutrition on growth performance, meat and carcass traits in either a conventional or an organic housing unit from weaning till slaughtering were evaluated in terminal crossbreeds of a paternal line and a maternal 3-way crossbreed of Seghers hybrid. All pigs were reared in a conventional way from birth till weaning (4 weeks). One week after weaning they were moved to either a conventional or an organic barn. Eight pens of 4 pigs (2 barrows and 2 gilts) were held in both housing types. The study started when the pigs reached the age of 10 weeks. Half of the groups in each barn received a conventional diet, and the other half received an organic diet. Both feeds were isocaloric, neither of them contained antibiotic growth promoters. Three-phase feeding was applied. The organic housing led to a higher feed intake throughout the experiment (P<0.001), which resulted in a faster growth (P<0.001) but a lower meat percentage (P<0.05). Organic nutrition did not affect growth performance and carcass quality. Neither organic nutrition nor housing led to relevant differences in meat quality traits.

Choroidal reaction and vascular repair after chorioretinal photocoagulation with the free-running neodymium-YAG laser.

The morphologic effects of the neodymium-YAG laser working in the free-running mode on the choroid of pigmented rabbit eyes have been studied by electron microscopy. Two different mechanisms closing the choroidal vessels were found. The larger vessels of the vascular lamina were closed by platelet aggregation, while within the choriocapillaries a network of fibrin could be observed. The endothelial cells of the vessels were found to be damaged in capillaries as well as in the larger vessels. Within the irradiated area, a revascularization process takes place, expanding from the border towards the center. The process begins a few days after treatment and continues for more than four months. The process of neovascularization is described in detail. Beside fibroblasts, cells could be found that were active in producing elastic fibers.

Quantification of fresh meat peptides by SDS-PAGE in relation to ageing time and taste intensity.

The extraction and quantification of fresh meat peptides in the molecular weight (MW) range between 3 and 17 kDalton (kDa) was examined, as well as their evolution during post-mortem ageing and their relation to taste intensity. Using a Tricine-sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) method, quantification of fresh meat peptides in this MW range was possible. Correlation coefficients higher than 0.98 were found between the absolute amounts of peptides loaded on the gel and the measured amounts expressed as cytochrome c equivalents. In contrast to the extraction in the presence of SDS, extraction with 0.1 N HCl, 3% HClO(4) and 0.9% NaCl only partially recovered peptides present in fresh meat samples in both the 3-10 and 10-17 kDa MW range. A substantial increase in peptide concentration in the 3-17 kDa MW range with time post-mortem in both pork and beef fresh muscle samples was found. For grilled beef longissimus lumborum and semimembranosus samples of different origin and ripening times, both the concentration of the peptides in the 3-10 kDa MW range and the intramuscular fat content were significantly related with taste panel intensity scores, while the correlation with the amount of peptides in the 10-17 kDa MW range was not significant.