The effect of free air carbon dioxide enrichment and nitrogen fertilisation on the chemical composition and nutritional value of wheat and barley grain

A rising atmospheric CO2 concentration might influence the nutrient composition of feedstuffs and consequently the nutritional value for livestock. The present study investigates the effects of atmospheric CO2 enrichment on the chemical composition and nutritional value of winter wheat cv. "Batis" and winter barley cv. "Theresa". Both cereals were grown at two different atmospheric CO2 concentrations (ambient CO2 [AMBI]: 380 ppm and enriched CO2 [free air carbon dioxide enrichment, FACE]: 550 ppm) for two growing seasons. The influence of two different nitrogen (N) fertilisation levels (adequate N supply [N100] and nearly 50% of adequate N supply [N50]) were studied as well. A significant effect was observed for the crude protein content, which declined at FACE condition in a range of 8-16 g kg(-1) in wheat and of 10-20 g kg(-1) in barley. A reduced N fertilisation level resulted in a strong reduction of crude protein concentration in both cereal species. In wheat, a decrease in N supply significantly enhanced the concentration of starch and crude fibre. In barley, only the concentration of fructose increased under FACE condition and reduced N fertilisation. The FACE did not have major effects on the concentrations of minerals, while the influence of N fertilisation was different for both cereals. Whereas no effects could be observed for barley, a reduced N supply caused a significant reduction in concentrations of zinc, manganese and iron in wheat. Furthermore, an undirected effect of atmospheric CO2 and N fertilisation levels were found for the amino acid concentrations. Based on these results, future scenarios of climate change would have an impact on the nutritional value of cereal grains.

Effects of cis-9,trans-11 and trans-10,cis-12 conjugated linoleic acid, linoleic acid, phytanic acid and the combination of various fatty acids on proliferation and cytokine expression of bovine peripheral blood mononuclear cells

Fatty acids may have an impact on immune functions, which is important in times of increased mobilization of body fat, e.g., around parturition. The aim of the present study was to investigate the effects of the CLA isomers cis-9,trans-11 and trans-10,cis-12, phytanic acid (PA), linoleic acid (LA) and a fatty acid (FA) mixture (containing 29.8% palmitic acid, 6.7% palmitoleic acid, 17.4% stearic acid and 46.1% oleic acid) on the proliferation of bovine blood mononuclear cells (PBMC) in vitro using alamar blue (AB) and 5-bromo-2′-deoxyuridine (BrdU) assay. Quantitative real time polymerase chain reaction analyses were performed to evaluate the expression of interleukin (IL)-4, IL-10, interferon (IFN)-γ, tumor necrosis factor (TNF)-α and peroxisome proliferator-activated receptor (PPAR)-γ in response to cis-9,trans-11 and LA. The IC₅₀ values did not differ between the investigated FA, but there were differences within the proliferation in the response of these FA in a concentration range between 20 and 148 µM (e.g., increased proliferation after treatment with lower concentrations of LA). No differences occurred when different FA combinations were tested. ConA stimulation increased the expression of TNF-α and IFN-γ, whereas IL-10 decreased. In general, neither the baseline expression nor the ConA-stimulated mRNA expression of cytokines and PPAR-γ were affected by the FA. In conclusion, all FA inhibit the proliferation of PBMC dose dependently without significantly altering the induced cytokine spectrum of activated bovine PBMC.

A commonly used rumen-protected conjugated linoleic acid supplement marginally affects fatty acid distribution of body tissues and gene expression of mammary gland in heifers during early lactation

Background

Conjugated linoleic acids (CLA) in general, and in particular the trans-10,cis-12 (t10,c12-CLA) isomer are potent modulators of milk fat synthesis in dairy cows. Studies in rodents, such as mice, have revealed that t10,c12-CLA is responsible for hepatic lipodystrophy and decreased adipose tissue with subsequent changes in the fatty acid distribution. The present study aimed to investigate the fatty acid distribution of lipids in several body tissues compared to their distribution in milk fat in early lactating cows in response to CLA treatment. Effects in mammary gland are further analyzed at gene expression level.

Methods

Twenty-five Holstein heifers were fed a diet supplemented with (CLA groups) or without (CON groups) a rumen-protected CLA supplement that provided 6 g/d of c9,t11- and t10,c12-CLA. Five groups of randomly assigned cows were analyzed according to experimental design based on feeding and time of slaughter. Cows in the first group received no CLA supplement and were slaughtered one day postpartum (CON0). Milk samples were taken from the remaining cows in CON and CLA groups until slaughter at 42 (period 1) and 105 (period 2) days in milk (DIM). Immediately after slaughter, tissue samples from liver, retroperitoneal fat, mammary gland and M. longissimus (13th rib) were obtained and analyzed for fatty acid distribution. Relevant genes involved in lipid metabolism of the mammary gland were analyzed using a custom-made microarray platform.

Results

Both supplemented CLA isomers increased significantly in milk fat. Furthermore, preformed fatty acids increased at the expense of de novo-synthesized fatty acids. Total and single trans-octadecenoic acids (e.g., t10-18:1 and t11-18:1) also significantly increased. Fatty acid distribution of the mammary gland showed similar changes to those in milk fat, due mainly to residual milk but without affecting gene expression. Liver fatty acids were not altered except for trans-octadecenoic acids, which were increased. Adipose tissue and M. longissimus were only marginally affected by CLA supplementation.

Conclusions

Daily supplementation with CLA led to typical alterations usually observed in milk fat depression (reduction of de novo-synthesized fatty acids) but only marginally affected tissue lipids. Gene expression of the mammary gland was not influenced by CLA supplementation.

Fusarium mycotoxins in conventionally and organically grown grain from Thuringia/Germany

Thefusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZON) were determined in conventionally and organically grown grain harvested 1998 in Thuringia/Germany. A total of 196 wheat samples and 69 rye samples was analysed.In this year with heavy rainfalls during the summer months, high concentrations offusarium mycotoxins were typical in grain grown in Germany, as the DON concentrations found here. DON concentrations in conventionally grown wheat were found to be significantly higher than in organically grown wheat. 69% of the conventionally grown wheat were tested positive, containing a mean concentration of 1540 µg/kg DM. In 54% of the organically grown wheat samples DON was detected with a mean value of 760 µg/kg DM. DON concentration in rye and ZON concentration in wheat showed similar tendencies.The different cultivars of conventionally grown wheat showed large differences in DON contamination.

Intestinal transport of deoxynivalenol across porcine small intestines

Deoxynivalenol (DON) is one of the most important trichothecenes, due to its worldwide distribution and common contamination of animal feed. It mainly affects the gastrointestinal tract and the immune system with a high susceptibility for swine. Lipopolysaccharides (LPS) are endotoxins and are part of the outer membrane of most gram-negative bacteria. They induce inflammatory responses under systemic application. We hypothesised that dietary DON as well as LPS challenge could affect the transport of DON in vitro. For assessment of this hypothesis, a total of 16 pigs were divided into two groups, Control and DON-feeding. In each group, four animals were injected intraperitoneally with LPS (5 µg/kg BW). Jejunal preparations were mounted on the Ussing chambers, and after luminal addition of DON at two different concentrations (4000 and 8000 ng/ml), buffer samples were collected at different time points to measure the concentration of DON using LC-MS/MS analysis. Our findings revealed a significant interaction effect between dietary DON and DON in vitro represented by higher mucosal uptake of DON in DON-fed animals. Animals challenged with LPS showed higher mucosal uptake but without significant effect of LPS. We concluded that the transport of DON was proportional to its concentration and DON in feed could have an effect on the transport of DON across porcine jejunal mucosa. LPS challenge induced no apparent significant effect on DON transport, although induction of acute phase reaction was present.

Interactions of deoxynivalenol and lipopolysaccharides on tissue protein synthesis in pigs

Possible interactions between the Fusarium toxin deoxynivalenol and lipopolysaccharides on in vivo protein synthesis were investigated in selected porcine tissues. A total of 36 male castrated pigs (initial weight of 26 kg) were used. 24 pigs were fed a control diet and 12 a Fusarium-contaminated diet (chronic oral deoxynivalenol, 3.1 mg/kg diet) for 37 days. Tissue protein synthesis was measured in pigs fed control diet after intravenous infusion of deoxynivalenol (100 µg/kg live weight/h), lipopolysaccharides (7.5 µg/kg live weight/h) or a combination of both compounds on the day of the measurements, while six pigs from the chronic oral deoxynivalenol group were intravenously treated with lipopolysaccharides (7.5 µg/kg live weight/h). Deoxynivalenol challenge alone failed to alter protein synthesis parameters. Fractional protein synthesis rates were exclusively reduced in liver, spleen and small intestine of lipopolysaccharides-treated pigs. Intravenous deoxynivalenol co-exposure enhanced the impacts of lipopolysaccharides on protein synthesis parameters in the spleen and the small intestine to some extent, while a chronic oral pre-exposure with deoxynivalenol relieved its effects in the spleen. Whether these interactions occur in other tissues and under other study conditions, especially toxin doses and route of entry into the body, needs to be examined further.

Fusarium toxin residues in physiological samples of piglets

Physiological samples of 100 piglets fed diets containing 0.01, 0.06, 0.15, 0.22 and 0.42 mg ZON and 0.2, 0.8, 1.0, 1.9 and 3.9 mg DON per kg over a period of 35±1.5 days were investigated for concentrations of deoxynivalenol (DON) and zearalenone (ZON) and their metabolites.DON was detected in serum, bile and urine in increasing concentrations corresponding to the diet contamination. The metabolite de-epoxy-DON was detected only in urine. The DON contamination of the diet was closely reflected by the serum concentrations of the piglets.ZON and its metabolite α-zearalenol were detected in bile fluid, liver and urine, while β-zearalenol was only detected in bile fluid. In serum neither ZON nor its metabolites were found. The total concentration of ZON plus its metabolites in the bile fluid corresponded well with the dietary contamination.For all analyses it has to be noted that toxin residues were detectable even in individual samples of piglets fed the control diet containing 0.01 mg ZON/kg and 0.2 mg DON/kg.

Progression of deoxynivalenol and zearalenone concentrations in straw of wheat infected artificially withFusarium culmorum

This investigation aimed at the progression of the contamination of theFusarium toxins deoxynivalenol (DON) and zearalenone (ZON) within the fractions straw, glumes and spindles from non-inoculated andFusarium-inoculated wheat. TheFusarium head blight (FHB)-susceptible wheat cultivar Ritmo was cultivated after the pre-crop maize and artificially infected withFusarium culmorum. Samples of whole wheat plants were taken once a week from anthesis until harvest and fractionated into straw, glumes and spindles. Samples were examined for deoxynivalenol and zearalenone and quantitatively determined by high performance liquid chromatography (HPLC) with diode-array detection (DAD) and fluorescence detection, respectively. Additionally, the impact of theFusarium inoculation on the crude protein content was scrutinised.Differences in the formation of deoxynivalenol and zearalenone with respect to date and concentration are shown by this trial. Deoxynivalenol was produced in higher concentrations and at earlier stages, whereas zearalenone was formed later and in smaller amounts. Furthermore, a rise of the deoxynivalenol concentration up to a maximum during the growing season, followed by a sudden decline at later stages until harvest, was observed. ThisFusarium infection resulted in an increased crude protein content in all of the three fractions.

Time dependent effects of graded levels of Fusarium toxin contaminated maize in diets for female piglets

The study was conducted to evaluate the effect of graded levels of the Fusarium toxins zearalenone (ZEA) and deoxynivalenol (DON) in diets for female piglets during 29 days of treatment on the development of performance, organ weights, clinical serum characteristics, differential blood counts and vulva morphology. For this purpose, 120 female weaned piglets with an initial mean bodyweight of 8.9±1.6 kg, were assigned to 5 feeding groups (n=24). The piglets of groups 1 to 5 received diets containing 0, 1.25, 2.5, 5 and 10% naturally contaminated maize instead of control maize, resulting in 0.01, 0.05, 0.08, 0.17 and 0.29 mg ZEA/kg, and 0.03, 0.59, 1.27, 2.01 and 4.52 mg DON/kg feed, respectively. After 1, 3, 8, 15, 22 and 29 days, 20 piglets (four piglets from each group) were slaughtered. Animals of group 5 consumed at least 20% less feed than animals of the other feeding groups. Body weight gain was significantly reduced in group 5 in the last week compared to group 2 and 3. Relative visceral organ weights were not affected by the treatments, but they mostly showed some minimal time dependent alterations. Uterus weights tended to be decreased in group 5 on day 15 of the experiment. Though not significant, signs of hyperoestrogenism such as swelling of the vulva became more pronounced with increasing time of exposure. Histopathological examination of organ specimens did not reveal any toxin related lesions. Total leukocytes, differential blood count and stimulation index of peripheral blood mononuclear cells were not affected by the diet, however, the proportion of lymphocytes increased while neutrophils decreased during the experiment independent of treatment. Clinical chemical serum characteristics were not affected by the treatments, however, they were somewhat affected by time. In conclusion, the dose related effects of ZEA and DON on performance and signs of hyperoestrogenism seemed to be dependent on exposure time.

Bioavailability of the Fusarium toxin deoxynivalenol (DON) from wheat straw and chaff in pigs

Fusarium infections do not only affect the grain, but also the rest of the plant, which result in contamination of plants with the mycotoxin deoxynivalenol (DON). The bioavailability of DON may be influenced by the matrix due to the differences in nutrient composition between grain and straw, particularly the high fibre component in straw. The experiment was carried out by exposing 18 male castrated pigs (30-40 kg live weight) with a single dose of DON from wheat grain, straw and chaff in the diet. The courses of DON serum concentrations were evaluated using toxicokinetic methods. The absorption of DON was not influenced by the source of DON. The invasion half-life of DON from grain, straw and chaff amounted to 0.76, 0.77 and 0.48 h, respectively, and were not significantly different. The elimination of DON was also not affected by the DON source. The bioavailability of DON, calculated by the dose corrected area under the curve of the serum-DON-concentrations, amounted to 81.9, 87.3 and 109.8% for straw, grain and chaff, respectively, without significant differences. Thus, the uptake of DON from straw may contribute comparably to the overall exposure of animals.

Occurrence of deoxynivalenol and zearalenone in commercial fish feed: an initial study

The control of mycotoxins is a global challenge not only in human consumption but also in nutrition of farm animals including aquatic species. Fusarium toxins, such as deoxynivalenol (DON) and zearalenone (ZEN), are common contaminants of animal feed but no study reported the occurrence of both mycotoxins in fish feed so far. Here, we report for the first time the occurrence of DON and ZEN in samples of commercial fish feed designed for nutrition of cyprinids collected from central Europe. A maximal DON concentration of 825 μg kg(-1) feed was found in one feed whereas average values of 289 μg kg(-1) feed were noted. ZEN was the more prevalent mycotoxin but the concentrations were lower showing an average level of 67.9 μg kg(-1) feed.

Effects of ergot alkaloids on liver function of piglets as evaluated by the (13)C-methacetin and (13)C-α-ketoisocaproic acid breath test

Ergot alkaloids (the sum of individual ergot alkaloids are termed as total alkaloids, TA) are produced by the fungus Claviceps purpurea, which infests cereal grains commonly used as feedstuffs. Ergot alkaloids potentially modulate microsomal and mitochondrial hepatic enzymes. Thus, the aim of the present experiment was to assess their effects on microsomal and mitochondrial liver function using the ¹³C-Methacetin (MC) and ¹³C-α-ketoisocaproic acid (KICA) breath test, respectively. Two ergot batches were mixed into piglet diets, resulting in 11 and 22 mg (Ergot 5-low and Ergot 5-high), 9 and 14 mg TA/kg (Ergot 15-low and Ergot 15-high) and compared to an ergot-free control group. Feed intake and live weight gain decreased significantly with the TA content (p < 0.001). Feeding the Ergot 5-high diet tended to decrease the 60-min-cumulative ¹³CO₂ percentage of the dose recovery (cPDR₆₀) by 26% and 28% in the MC and KICA breath test, respectively, compared to the control group (p = 0.065). Therefore, both microsomal and mitochondrial liver function was slightly affected by ergot alkaloids.

Effects of conjugated linoleic acids fed to dairy cows during early gestation on hematological, immunological, and metabolic characteristics of cows and their calves

The aim of the present experiment was to test the stimulation ability of peripheral blood mononuclear cells (PBMC) expressed as stimulation index (SI) of newborn calves and of their dams fed a control fat supplement (CON, n=6) or 50 and 100g/d of a CLA-containing fat supplement (CLA50, n=5, and CLA100, n=6, respectively) during the preceding lactation period for 182 d after calving. The total intake of cis-9,trans-11 and trans-10,cis-12 CLA by groups CLA50 and CLA100 amounted to 4 and 8 g/d each, respectively. For this purpose, blood was collected immediately after parturition from calves before and after colostrum intake, and from cows after parturition and 21 d later. The SI was related to the fatty acid composition of erythrocyte and milk lipids and to various hematological and clinical-chemical parameters. Retrospective evaluation revealed that depletion time (i.e., the individual period elapsed between the day of terminating the feeding of the experimental diet in the preceding lactation period and the day of calving) ranged from 190 to 262 d, which corresponded to fetal exposure times of 19 to 102 d. The SI from cows increased significantly by 77 and 55%, within 21 d after calving according to the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl-tetrazolium bromide (MTT) and Alamar Blue assays, respectively. However, feeding of 50 g of the CLA product failed to demonstrate this increase in the MTT assay. Moreover, SI was significantly lower for calves whose dams belonged to the CLA50 group, whereas stimulation ability was comparable for the PBMC from calves whose mothers were treated with CON and CLA100. Plasma metabolites (total bilirubin, total cholesterol, glucose, nonesterified fatty acids, 3-β-hydroxybutyrate, total protein, and albumin) and hematological parameters (hematocrit, white blood cell profile) were not significantly influenced by dietary treatments of the cows in the preceding lactation period. Although the fatty acid pattern of erythrocyte lipids of cows remained uninfluenced, that of calves showed alterations due to the feeding type of their dams. For example, C16:0 increased significantly from 14.4 to 16.9% of total fatty acid methyl esters, whereas cis-9,trans-11 CLA increased slightly from 0.11 to 0.15% at the same time in calves when their mothers were fed the CLA100 instead of the CON diet. Fatty acid profile of colostrum was significantly different from that of milk after 3 wk for most of the detected fatty acids, but was not influenced by diet type. In conclusion, feeding a CLA-containing fat supplement during the preceding lactation and gestation period exerted effects on the stimulation ability of PBMC from cows and calves for the subsequent parturition. However, CLA dose effects were inconsistent and require further investigation.

The effects of iodine level and source on iodine carry-over in eggs and body tissues of laying hens

In the presented study the effect of different iodine (I) levels and sources in hen feed on the iodine concentration of different tissues, blood serum, and eggs of laying hens was studied. For this purpose, two experiments were conducted with 30 laying hens each. In these experiments feed was enriched with KI and Ca(IO(3))(2), respectively, at 0 (Control), 0.25, 0.5, 2.5 and 5 mg I/kg feed, resulting a analysed iodine level from 0.44 to 4.20 mg/kg feed. After four weeks experimental feeding the iodine concentrations of thyroid glands, blood, meat, liver, abdominal fat and eggs were measured with inductively coupled plasma mass spectrometry. The experimental treatment did not affect hen performance. The iodine supplementation significantly increased the iodine concentration of eggs (144-1304 μg/kg), thyroid glands (3367-5975 μg/g), blood serum (16-67 μg/kg) and liver (13-43 μg/kg). Meat (about 14 μg I/kg) and abdominal fat (about 12 μg I/kg) were not significantly affected by iodine treatment. Comparative regression analyses showed that at a similar iodine intake, the supply via KI resulted in significantly higher iodine deposition into eggs than Ca(IO(3))(2). Due to the high carry-over of iodine into eggs, eggs may considerably contribute to the iodine supply of the consumers.

Technical note: identification of reference genes for gene expression studies in different bovine tissues focusing on different fat depots

Selection of stable reference genes (REF) is important in real-time PCR data normalization. Bovine tissues such as the mammary gland, liver, muscle, and s.c. fat from the tail head have been thoroughly explored for stable REF, whereas fewer reports exist for other fat depots. Therefore, a suitable combination of REF was tested for different tissues of dairy cattle. Holstein dairy heifers (n = 25) were supplemented (100 g/d) with a control fat (n = 15) without conjugated linoleic acids or with rumen-protected conjugated linoleic acids (n = 10) from the day of calving until slaughter at 1, 42, or 105 d postpartum (n = 5, 10, and 10, respectively). Samples from 6 fat depots (omental, mesenterial, retroperitoneal, s.c. tail head, s.c. withers, and s.c. sternum), liver, semitendinosus muscle, and mammary gland were collected. The REF mRNA were quantified and their stability was analyzed using geNorm(plus). The 3 most stable REF in individual fat tissues and muscle were EMD (emerin), POLR2A (RNA polymerase II), and LRP10 (lipoprotein receptor-related protein 10); in mammary gland were MARVELD1 (marvel domain containing 1), EMD, and LRP10; and in liver were HPCAL1 (hippocalcin-like 1), LRP10, and EIF3K (Eukaryotic translation initiation factor 3). The 3 most stable REF in s.c. fat were EMD, LRP10, and EIF3K; in visceral fat were POLR2A, LRP10, and MARVELD1; and for all 6 adipose tissues were LRP10, EIF3K, and MARVELD1. When the mammary gland was added to the 6 adipose depots, at least 5 REF (LRP10, POLR2A, EIF3K, MARVELD1, and HPCAL1) were needed to reach the threshold of 0.15. Addition of liver to the above-mentioned tissues increased the V value. The data improve the comparison of gene expression between different fat depots. In each case, GAPDH had the lowest stability value.

Effect of niacin supplementation on rumen fermentation characteristics and nutrient flow at the duodenum in lactating dairy cows fed a diet with a negative rumen nitrogen balance

The aim of the present experiment was to ascertain if a daily niacin supplementation of 6 g/cow to lactating dairy cow diets can compensate for the decrease in rumen microbial fermentation due to a negative rumen nitrogen balance (RNB). A total of nine ruminally and duodenally fistulated lactating multiparous German Holstein cows was used. The diets consisted of 10 kg dry matter (DM) maize silage and 7 kg DM concentrate and differed as follows: (i) Diet RNB- (n = 6) with energy and utilisable crude protein (CP) at the duodenum (uCP) according to the average requirement of the animals, but with a negative RNB (-0.41 g N/MJ metabolisable energy [ME]); (ii) Diet RNB0 (n = 7) with energy, uCP, and RNB (0.08 g N/MJ ME) according to the average requirement of the animals; and (iii) Diet NA (nicotinic acid; n = 5), which was the same diet as RNB-, but supplemented with 6 g niacin/d. The negative RNB affected the rumen fermentation pattern and reduced ammonia content in rumen fluid and the daily duodenal flows of microbial CP (MP) and uCP. Niacin supplementation increased the apparent ruminal digestibility of neutral detergent fibre. The efficiency of microbial protein synthesis per unit of rumen degradable CP was higher, whereby the amount of MP reaching the duodenum was unaffected by niacin supplementation. The number of protozoa in rumen fluid was higher in NA treatment. The results indicated a more efficient use of rumen degradable N due to changes in the microbial population in the rumen when niacin was supplemented to diets deficient in RNB for lactating dairy cows.

Inactivation of deoxynivalenol-contaminated cereal grains with sodium metabisulfite: a review of procedures and toxicological aspects

Both hydrothermal treatment and wet preservation of mainly deoxynivalenol (DON)-containing, Fusarium toxin (FUS)-contaminated cereal grains with sodium metabisulfite (Na2S2O5 [SBS]) were successfully demonstrated to reduce the DON contamination through formation of the sulfonated derivative of DON, termed as DON sulfonate (DONS). The wet preservation is particularly interesting from a practical viewpoint as it can be easily performed at the farm level where the cereal grains are harvested and utilized in pig feeding. This review compiles the literature with regard to the chemical characterization and the detection of DONS, technical procedures and their efficacies, toxicological aspects and toxic effects of DON, DONS and SBS, and detection of DONS, DON and further metabolites in physiological specimens of pigs.

Urinary excretion and metabolism of procyanidins in pigs

SCOPE

Aim of this study was to investigate urinary excretion and metabolism of procyanidins a group of secondary plant metabolites with many beneficial health effects described in literature.

METHODS AND RESULTS

To investigate the metabolism of procyanidins in the absence of flavan-3-ols, centrifugal partition chromatography was used for their reduction in a grape seed extract to a level of almost zero. After administration of the monomer reduced grape seed extract (mredGSE) containing procyanidins B1, B2, B3, B4, C1 to pigs flavan-3-ols, their methyl derivatives, dimeric and trimeric procyanidins were determined in urine by high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS). Maximal concentrations of procyanidins 6 h after administration vary from 5 to 30 ng/mg creatinine. Total excretion of flavan-3-ols and their methyl derivatives indicates an increasing trend for pigs given mredGSE in comparison to pigs of the control group. Flavan-3-ols were conjugated and methylated to a great extent in comparison to dimeric and trimeric procyanidins. In the case of low molecular weight metabolites, an increasing trend was observed for hippuric acid, not for phenolic acids.

CONCLUSIONS

Ratios of total excretion of procyanidins to administrated amounts between 0.004% (C1) and 0.019% (B4) suggest a poor urinary excretion by pigs. A transfer of these results to humans is possible due to their similar gastrointestinal tract.

Lipolysis in early lactation is associated with an increase in phosphorylation of adenosine monophosphate-activated protein kinase (AMPK)α1 in adipose tissue of dairy cows

Adenosine monophosphate-activated protein kinase (AMPK)α1 is activated in the context of triacylglycerol hydrolysis in adipose tissue in monogastric animals. This study describes AMPKα1 protein expression and the occurrence of its phosphorylated form (pAMPKα1) in different adipose tissue depots as influenced by time and postpartum diet in dairy cows. Biopsy samples were obtained from subcutaneous (SCAT) and retroperitoneal (RPAT) adipose tissues of 20 Holstein cows 21 d prepartum (ap) and 1 and 21 d postpartum (pp). After d 1 pp, cows were randomly assigned to 2 groups (n=10) and fed different amounts of concentrate until the third biopsy sampling at 21 d pp. Protein expression of AMPK and the extent of its phosphorylation in adipose tissue were measured by semiquantitative Western blotting. Results were not influenced by postpartum feeding. Therefore, both groups were pooled and data analyzed together. Expression of AMPKα1 in SCAT showed a decrease over time, resulting in lower expression at 1d pp compared with 21 d ap. Expression in RPAT was maintained over time. Phosphorylation increased in SCAT, showing a greater extent of phosphorylation at d 21 pp compared with 21 d ap. In RPAT, this could be seen as a trend. The proportion of pAMPKα1 to AMPKα1 significantly increased over time in both tissues. In the first adipose tissue sampling (21 d ap), AMPKα1 protein expression and extent of phosphorylation were significantly higher in RPAT than in SCAT. Lipolysis in early lactation of dairy cows was associated with an increase in phosphorylation of AMPKα1 and ratio of pAMPKα1 to AMPKα1 in bovine adipose tissues. This indicates that AMPKα1 may be involved in the regulation of energy metabolism of bovine adipose tissues.

Humic substances failed to prevent the systemic absorption of deoxynivalenol (DON) and its adverse effects on piglets

The aim of this study was to examine the effects of a control diet (CON, 0.25 mg DON/kg diet) or a Fusarium toxin-contaminated diet (FUS, 4.49 mg DON/kg diet) without and with humic substances (HS) (CON-HS and FUS-HS, 0.23 and 4.56 mg DON/kg diet, respectively) on piglets during a 5-week growth trial starting after weaning (6.7 ± 0.9 kg live weight, n = 20/group). Feed intake was significantly reduced by feeding the FUS containing diets by approximately 21% compared with the CON diet irrespective of HS supplementation. The decrease in live weight gain paralleled the feed intake depression and amounted to approximately 26%. Feeding the FUS diet was clearly reflected by the DON levels in blood. While only traces of DON with median concentrations of 3 ng/ml (2-5 ng/ml) and 2 ng/ml (0-3 ng/ml) were detected in piglets fed the CON and CON-HS diets, respectively, significantly higher levels of 22.5 ng/ml (7-30 ng/ml) and 23.5 ng/ml (15-32 ng/ml) were found in piglets fed the FUS and FUS-HS diet, respectively. The urinary excretion of DON and its metabolite de-epoxy-DON as percentage of DON intake was not significantly influenced by HS supplementation and amounted to 24.1 and 20.2% for groups FUS and FUS-HS, respectively. In conclusion, the tested HS preparation cannot be recommended as a DON inactivating feed supplement for pigs.

Effect of niacin supplementation on digestibility, nitrogen utilisation and milk and blood variables in lactating dairy cows fed a diet with a negative rumen nitrogen balance

The aim of the present experiment was to determine if a niacin supplementation of 6 g/d to lactating dairy cow diets can compensate negative effects of a rumen nitrogen balance (RNB) deficit. A total of nine ruminally and duodenally fistulated lactating multiparous German Holstein cows were successively assigned to one of three diets consisting of 10 kg maize silage (dry matter [DM] basis) and 7 kg DM concentrate: Diet RNB- (n = 6) with energy and utilisable crude protein at the duodenum (uCP) according to the average requirement of the animals but with a negative RNB (-0.41 g N/MJ metabolisable energy [ME]); Diet RNB0 (n = 7) with energy, uCP and a RNB (0.08 g N/MJ ME) according to the average requirement of the animals and, finally, Diet NA (n = 5), which was the same diet as RNB-, but supplemented with 6 g niacin/d. Samples of milk were taken on two consecutive days, blood samples were taken on one day pre- and post-feeding and faeces and urine were collected completely over five consecutive days. The negative RNB reduced milk and blood urea content and apparent total tract digestibility of DM, organic matter (OM) and neutral detergent fibre (NDF). Also N excretion with urine, the total N excreted with urine and faeces and the N balance were reduced when the RNB was negative. Supplementation of niacin elevated plasma glucose concentration after feeding and the N balance increased. Supplementing the diet with a negative RNB with niacin led to a more efficient use of dietary N thereby avoiding the negative effects of the negative RNB on the digestibility of DM, OM and NDF.

Fatty acid profile and proliferation of bovine blood mononuclear cells after conjugated linoleic acid supplementation

BACKGROUND

Conjugated linoleic acids (CLA) are in focus of dairy cattle research because of its milk fat reducing effects. Little is known about the impact of CLA on immune function in dairy cows. Therefore, in the present study we investigated the effects of a long term supplementation of dairy cows with CLA on the fatty acid profile of peripheral blood mononuclear cells (PBMC) and their proliferation ex vivo.

RESULTS

The supplementation of dairy cows with either 100 g/d of a control fat preparation (CON, n = 15), 50 g/d of the control fat preparation and 50 g/d CLA supplement - containing 12.0% cis-9, trans-11 and 11.9% trans-10, cis-12 CLA of total fatty acid methyl esters - (CLA-50, n = 15) or 100 g/d of the CLA supplement (CLA-100, n = 16) did not influence the major fatty acids (C18:0, C16:0, cis-9 C18:1, cis-9, cis-12 C18:2, cis-5, cis-8, cis-11, cis-14 C20:4) in the lipid fraction of PBMC. The proportion of trans-10, cis-12 CLA of total fatty acids was increased in both CLA supplemented groups, but there was no effect on the cis-9, trans-11 isomer. Furthermore, the proportion of trans-9 C18:1 and cis-12 C24:1 was reduced in the CLA-100 group. The mitogen stimulated cell proliferation was not influenced by CLA feeding.

CONCLUSION

CLA supplementation influenced the FA profile of some minor FA in PBMC, but these changes did not lead to differences in the mitogen induced activation of the cells.

Effect of conjugated linoleic acid on proliferation and cytokine expression of bovine peripheral blood mononuclear cells and splenocytes ex vivo

Twenty-five primiparous Holstein cows were divided into five experimental groups (five animals per group) by different feeding (control fat preparation [CON] or conjugated linoleic acid [CLA] supplement) and slaughtering times. The daily consumption of CLA was 6.0 g of the trans-10, cis-12 CLA-isomer and 5.7 g cis-9, trans-11 CLA isomer. An initial group (IG) was slaughtered one day post partum (pp) and the remaining 20 animals after 42 and 105 days pp, respectively. Blood for peripheral blood mononuclear cells (PBMC) separation was taken seven days ante partum and immediately before slaughter. The spleen was removed during dissection for isolation of splenocytes and samples for histopathological examination. Cell viability and Concanavalin A-stimulated proliferation was analysed by MTT and Alamar Blue assay. Basal expression of cytokines (interleukin [IL]-4, IL-10, IL-12, tumour necrosis factor alpha [TNF-alpha] and interferon gamma [IFN-gamma]) was measured by quantitative real time polymerase chain reaction (qRT-PCR) in unstimulated PMBC and splenocytes. With PBMC, stimulation indices increased from 1 day pp to 105 days pp with no differences between CLA and CON groups. With splenocytes, the stimulation index of the CLA group was lower compared to CON group 105 days pp. Baseline expression of cytokines was not effected by CLA feeding comparing similar time points. Also, no differences occurred in the expression of IL-4 in PBMC and IL-10 as well as TNF-alpha in both cell populations, when comparing the feeding groups separately with IG. IL-4 was more frequently expressed in CLA group 42 days pp in splenocytes. IFN-gamma expression was increased 105 days pp in CLA group in splenocytes and PBMC. IL-12 was higher expressed 105 days (PBMC) or 42 days pp (splenocytes) when compared to IG. There was no effect of CLA feeding or slaughter time on histopathology of the spleen. In conclusion, the present results demonstrate an inhibiting effect of CLA on the mitogen-induced activation of splenocytes.

Effects of ergot alkaloids on liver function of piglets can be detected by the [(13)C]methacetin breath test irrespective of oral or intramuscular route of tracer administration

Ergot alkaloids (sum=total alkaloids, TA) originate from the phyto-pathogenic fungus Claviceps purpurea and might exert feed intake depressing and hepatotoxic effects on animals. The aim of the study was to evaluate TA effects on performance and liver function of piglets with the [(13)C]methacetin breath test and two routes of tracer administration (orally, p.o.; intramuscularly, i.m.). Two ergot batches were mixed into piglet diets resulting in 21 and 17 mg TA kg(-1) (Ergot-5 and -12, respectively) and compared with an ergot-free control diet. Feed intake was significantly depressed after feeding the ergot containing diets (p=<0.001). The time at maximum (13)CO(2) exhalation (t (max)) and the half-life (t (0.5)) were not influenced by treatments and varied between 25 and 68 min after the p.o., and 28 and 62 min after the i.m. administration of [(13)C]methacetin, respectively. The cumulative (13)C recovery (cPDR(30)) was significantly lower due to feeding the diet Ergot-5 (6.6 %) compared with the Ergot-12 (8.8 %) and the control diet (9.7 %) irrespective of the route of tracer administration (p=0.044). As a discrimination of the diet effects through both tracer administration routes is possible, the i.m. application should be preferred in piglets as this causes less stress than the oral forced administration.

Hormone-sensitive lipase protein expression and extent of phosphorylation in subcutaneous and retroperitoneal adipose tissues in the periparturient dairy cow

Lipomobilization is essential for dairy cows to balance the energy requirement for milk production in early lactation. This study aimed to determine the role of hormone-sensitive lipase (HSL) and its activation by phosphorylation at Ser 660 (HSLp660) and 563 (HSLp563) in different adipose tissue depots as influenced by time and postpartum diet in dairy cows. Biopsy samples were obtained from s.c. (SCAT) and retroperitoneal (RPAT) adipose tissues of 20 Holstein cows 21 d prepartum, and 1 and 21 d postpartum. After d 1 postpartum, cows were randomly assigned to 2 groups (n=10). Groups received diets with either a concentrate-to-roughage ratio on a dry matter basis of 30:70% (low-concentrate, LC, group) or 60:40% (high-concentrate group), fed until the third biopsy sampling 21 d postpartum. Dry matter intake, milk yield, and milk composition were recorded. Blood samples were taken weekly, starting 21 d prepartum and analyzed for nonesterified fatty acids, β-hydroxybutyrate (BHBA), glucose, and insulin. Protein expression of HSL and its extent of phosphorylation in adipose tissue were measured by semiquantitative Western blotting. Total HSL expression was lower in both adipose tissues 1 d after calving compared with prepartum sampling (SCAT: 4.10±0.5 vs. 2.4±0.3; RPAT: 11.1±1.3 vs. 6.6±1.1). Phosphorylation at Ser 660 was higher 21 d postpartum compared with 21 d prepartum in RPAT (2.9±0.3 vs. 4.6±0.6). Phosphorylation at Ser 563 was higher 21 d postpartum than 21 d prepartum in SCAT (0.6±0.1 vs. 3.9±1.1), and in RPAT a difference was observed between 21 d prepartum and 1 d postpartum (1.0±0.1 vs. 3.3. ± 0.6). On d 21 postpartum, the LC group showed a lower extent of Ser 563 phosphorylation in RPAT (3.9±0.8 vs.10.0±1.9) and a higher concentration of serum BHBA (0.77±0.05 vs. 0.47±0.11) than did the high-concentrate group. An inhibitory influence of higher BHBA concentrations on HSL phosphorylation in the LC group could be a possible explanation. On comparing RPAT to SCAT, HSL expression and the extent of Ser 660 and 563 phosphorylation was higher in RPAT at 21 d prepartum (HSL: 4.1±0.5 vs. 11.1±1.2; HSLp660 1.3±0.2 vs. 2.9±0.3; HSLp563: 0.6±0.1 vs. 1.0±0.1). In conclusion, the postpartum feeding regimen influenced the phosphorylation pattern, especially in RPAT, implying a regulatory role for different phosphorylation sites in adaptive lipolysis of dairy cows. It is suggested that RPAT is more sensitive to periparturient challenges than is SCAT.

Effect of trans-10, cis-12 conjugated linoleic acid on performance, adipose depot weights, and liver weight in early-lactation dairy cows

In feeding practice, conjugated linoleic acid (CLA) supplements are used to decrease milk fat excretion in early-lactation dairy cows to save energy to counteract the physiological negative energy balance. The present study was conducted to examine the effects of CLA on energy metabolism, changes in liver weight, and the weight of different adipose depots during early lactation. Primiparous lactating German Holstein cows (n=25) were divided into 5 groups and each group contained 5 animals. The experiment started 21 d prepartum and continued until 105 d in milk (DIM). Cows were slaughtered at 1, 42, and 105 DIM. The experiment was divided into a prepartum period (21 d prepartum until calving), period 1 (1 until 42 DIM), and period 2 (>42 until 105 DIM). In the prepartum period, all animals were housed together and fed the same diet with no CLA supplementation. At 1 DIM, an initial group, with no CLA supplementation, was slaughtered. The 20 remaining cows were assigned to 2 diets. One group received 100g/d of a control fat supplement (CON; n=10) and the other group 100g/d of a CLA supplement (CLA; n=10) from 1 DIM until slaughter. Five cows of each feeding group were slaughtered after 42 DIM and the remaining animals after 105 DIM. The CLA supplement contained approximately 10% each of trans-10, cis-12 CLA and cis-9, trans-11 CLA. During the slaughter process the empty body weight was recorded and the omental, mesenteric, retroperitoneal, and s.c. adipose depots, as well as the liver, were dissected and weighed. The CLA treatment decreased milk fat content in period 1 (14.1%). In period 2, milk fat content (25.4%) and yield (17.1%) were lower in the CLA group. No effect of CLA on milk yield was observed. The net energy intake, milk energy output, and the calculated energy balance remained unchanged by CLA supplementation. No effect of CLA on the weights of liver, omental, mesenteric, or s.c. adipose depots was observed when related to empty body weight. Liver weight increased with DIM, whereas the retroperitoneal adipose depot weight decreased at the same time. Compared with the initial group, the retroperitoneal adipose depot weight for control animals slaughtered after 42 DIM was decreased (47.7%); however, for the CLA group slaughtered after 42 DIM, a trend to a lower retroperitoneal adipose depot weight (34.0%) was observed. This suggests a CLA-induced deceleration of mobilization of the retroperitoneal adipose depot during the first 42 DIM.

Physiological and conjugated linoleic acid-induced changes of adipocyte size in different fat depots of dairy cows during early lactation

The aim of this study was to investigate the effects of lactation and conjugated linoleic acid (CLA) supplementation on adipocyte sizes of subcutaneous (s.c.) and visceral (VC) fat depots in primiparous dairy cows during the first 105 d in milk (DIM). German Holstein heifers (n=25) were divided into a control (CON) and a CLA group. From 1 DIM until sample collection, CLA cows were fed 100g of CLA supplement/d (about 6% of c9,t11 and t10,c12 isomers each), whereas the CON cows received 100g of fatty acid mixture/d instead of CLA. The CON cows (n=5 each) were slaughtered at 1, 42, and 105 DIM, and the CLA cows (n=5 each) were slaughtered at 42 and 105 DIM. Adipose tissues from 3s.c. depots (tailhead, withers, and sternum) and from 3 VC depots (omental, mesenteric, and retroperitoneal) were sampled. Hematoxylin-eosin staining was done to measure adipocyte area (μm(2)). Retroperitoneal adipocyte sizes were mostly larger than adipocytes from the other sites, independent of lactation time and treatment. Significant changes related to duration of lactation were limited to retroperitoneal fat: adipocyte sizes were significantly smaller at 105 DIM than at 1 DIM in CON cows. Adipocyte sizes were decreased in s.c. depots from the tailhead at 105 DIM and from the sternum at 42 DIM in CLA versus CON cows, whereas for VC depots, adipocyte sizes were decreased in mesenteric fat at 42 and 105 DIM, and in omental and retroperitoneal fat, at 105 DIM in CLA versus CON cows. Within the CLA group, adipocyte sizes were smaller in the s.c. depot from the tailhead at 105 DIM than at 42 DIM. Adipocyte sizes and depot weights were significantly correlated in s.c. depots (r=0.795) in the CLA group and in retroperitoneal fat both in the CON (r=0.698) and the CLA (r=0.723) group. In conclusion, CLA-induced decreases in adipocyte size indicate lipolytic or antilipogenic effects of CLA, or both effects, on adipose tissue in primiparous dairy cows.

Influence of in vitro supplementation with lipids from conventional and Alpine milk on fatty acid distribution and cell growth of HT-29 cells

Background

To date, the influence of milk and dairy products on carcinogenesis remains controversial. However, lipids of ruminant origin such as conjugated linoleic acids (CLA) are known to exhibit beneficial effects in vitro and in vivo. The aim of the present study was to determine the influence of milk lipids of different origin and varying quality presenting as free fatty acid (FFA) solutions on cellular fatty acid distribution, cellular viability, and growth of human colon adenocarcinoma cells (HT-29).

Methods

FAME of conventional and Alpine milk lipids (ML_con, ML_alp) and cells treated with FFA derivatives of milk lipids were analyzed by means of GC-FID and Ag⁺-HPLC. Cellular viability and growth of the cells were determined by means of CellTiter-Blue^®-assay and DAPI-assay (4',6-diamidino-2-phenylindole dihydrochloride), respectively.

Results

Supplementation with milk lipids significantly decreased viability and growth of HT-29 cells in a dose- and time-dependent manner. ML_alp showed a lower SFA/MUFA ratio, a 8 fold increased CLA content, and different CLA profile compared to ML_con but did not demonstrate additional growth-inhibitory effects. In addition, total concentration and fatty acid distribution of cellular lipids were altered. In particular, treatment of the cells yielded highest amounts of two types of milk specific major fatty acids (μg FA/mg cellular protein) after 8 h of incubation compared to 24 h; 200 μM of ML_con (C16:0, 206 ± 43), 200 μM of ML_alp (C18:1 c9, (223 ± 19). Vaccenic acid (C18:1 t11) contained in milk lipids was converted to c9,t11-CLA in HT-29 cells. Notably, the ratio of t11,c13-CLA/t7,c9-CLA, a criterion for pasture feeding of the cows, was significantly changed after incubation for 8 h with lipids from ML_alp (3.6 - 4.8), compared to lipids from ML_con (0.3 - 0.6).

Conclusions

Natural lipids from conventional and Alpine milk showed similar growth inhibitory effects. However, different changes in cellular lipid composition suggested a milk lipid-depending influence on cell sensitivity. It is expected that similar changes may also be evident in other cell lines. To our knowledge, this is the first study showing a varied impact of complex milk lipids on fatty acid distribution in a colon cancer cell line.

The Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) in animal feeding

The contamination of cereal grains with toxic secondary metabolites of fungi, mycotoxins, is a permanent challenge in animal nutrition as health and performance of the animals may be compromised as well as the quality of animal derived food. Therefore the present article reviews the issue of mycotoxins in animal nutrition. As the Fusarium toxins deoxynivalenol (DON) and zearalenone (ZON) are of particular importance under the production conditions in central Europe and Germany, with respect to their frequent occurrence in toxicologically relevant concentrations, special emphasis is layed on those mycotoxins. The effects of DON and ZON on susceptible animals as well as management strategies to cope with the contamination of grain with those toxins are reviewed.