Effects of dietary-reduced nitrogen (N) and phosphorus (P) on N and P balance, retention and nutrient digestibility of contemporary fattening pigs fed ad libitum.

The reduction of nitrogen (N) and phosphorus (P) in fattening pigs' diets is one possible approach to lower N and P excretion in livestock farming relative to N and P intake. Due to the implementation of the European Nitrates Directive and the consecutive amendments to the German fertiliser legislation since 2017, N- and P-reduced diets for fattening pigs are becoming more and more important and are increasingly used in practice. To investigate the effects of such diets on N and P balance and retention as well as on nutrient digestibility of contemporary fattening pigs, a balance experiment was performed with eight barrows (average live weight = 61.5 ± 2.1 kg) which were surgically fitted with a simple T-cannula at the terminal ileum. The pigs received a control diet meeting nutrient requirements (CON) and an N- and P-reduced diet (NPred) ad libitum (n = 4/diet) in a 3-phased feeding regimen (3 weeks/phase). In the last week of each phase, faeces and urine were collected quantitatively for 5 days followed by a 2 × 12 hours collection of ileal digesta. Daily feed intake, live weight gain and feed-to-gain ratio did not differ between CON and NPred. NPred-fed pigs consumed 10.5% (p = 0.006) and excreted 28.3% (p = 0.028) less N than CON-fed pigs. Phosphorus excretion was lowered by 15.1% in NPred-fed pigs (p = 0.012). N and P retention did not differ between CON and NPred, but were elevated in comparison to other studies. N and P efficiency, expressed as nutrient retention divided by nutrient intake, was higher in NPred - than CON-fed pigs (N: 68 vs 60%, P: 54.2 vs 49.3%). Apparent post-ileal digestibility coefficient (DCpost-ileal) and apparent total tract digestibility coefficient (DCtotal) of crude protein were higher in NPred - than CON-fed pigs (p < 0.013), but apparent precaecal digestibility coefficient (DCpc) of crude protein was unaffected by diet. DCpc, DCpost-ileal and DCtotal of P were similar for CON- and NPred-fed pigs. NPred-fed pigs showed an elevated DCpc and DCtotal of organic matter, N-free-extractives and starch compared to CON-fed pigs. DCpc of calcium was also higher in NPred-fed pigs. In conclusion, the results suggest that N- and P-reduced feeding of fattening pigs remains an effective strategy to lower the N and P release into the environment. Furthermore, results indicate that N- and P-reduced feeding leads to a higher N and P efficiency in contemporary fattening pigs.

Short-term exposure of dairy cows to pyrrolizidine alkaloids from tansy ragwort (Jacobaea vulgaris Gaertn.): effects on health and performance.

The increasing spread of ragworts is observed with concern. Ragworts like tansy ragwort (Jacobaea vulgaris Gaertn.) or marsh ragwort (J. aquatica) contain pyrrolizidine alkaloids (PA) which may induce hepatotoxic effects. Grazing animals usually avoid ragworts if their pasture management is appropriate. Preserved feed prepared from ragworts contaminated meadows may, however, lead to a significant exposure to PA. Previous studies on toxicity of PA for dairy cows revealed inconsistent results due to feeding ragwort plant material which was associated with heterogeneous PA exposure and thus failed to conclusively deduce critical PA doses. Therefore, the aim of the present study was to expose dairy cows (n = 4 per group) in a short-term scenario for 28 days with increasing PA doses (PA1: 0.47 mg PA/kg body weight (BW)/day (d); PA2: 0.95 mg PA/kg BW/d; PA3: 1.91 mg PA/kg BW/d) via oral administration by gavage of a defined PA-extract. While group PA3 was dosed with the PA-extract alone, groups PA2 and PA1 received PA-extracts blended in similar volumes with molasses to provide comparable amounts of sugar. Additionally, two control groups were treated either with water (CONWater) or with molasses (CONMolasses) to assess the effects of sugar without PA interference. While clinical traits including dry matter intake, milking performance, rectal body temperature, ruminal activity and body condition score (BCS) were not influenced by PA exposure, activities of enzymes indicative for liver damages, such as gamma-glutamyltransferase (GGT), aspartate aminotransferase (AST) and glutamate dehydrogenase (GLDH), increased significantly over time at an exposure of 1.91 mg total PA/kg BW/d.

Upcycling of recycled minerals from sewage sludge through black soldier fly larvae (Hermetia illucens): Impact on growth and mineral accumulation.

Phosphorous (P) resources are finite. Sewage sludge recyclates (SSR) are not only of interest as plant fertilizer but also as potential source of minerals in animal nutrition. However, besides P and calcium (Ca), SSR contain heavy metals. Under EU legislation, the use of SSR derivatives in animal feed is not permitted, but given the need to improve nutrient recycling, it could be an environmentally sound future mineral source. Black soldier fly larvae (BSFL) convert low-grade biomass into valuable proteins and lipids, and accumulate minerals in their body. It was hypothesized that BSFL modify and increase their mineral content in response to feeding on SSR containing substrates. The objective was to evaluate the upcycling of minerals from SSR into agri-food nutrient cycles through BSFL. Growth, nutrient and mineral composition were compared in BSFL reared either on a modified Gainesville fly diet (FD) or on FD supplemented with either 4% of biochar (FD + BCH) or 3.6% of single-superphosphate (FD + SSP) recyclate (n = 6 BSFL rearing units/group). Larval mass, mineral and nutrient concentrations and yields were determined, and the bioaccumulation factor (BAF) was calculated. The FD + SSP substrate decreased specific growth rate and crude fat of BSFL (P < 0.05) compared to FD. The FD + SSP larvae had higher Ca and P contents and yields but the BAF for Ca was lowest. The FD + BCH larvae increased Ca, iron, cadmium and lead contents compared to FD. Larvae produced on FD + SSP showed lower lead and higher arsenic concentration than on FD + BCH. Frass of FD + BCH had higher heavy metal concentration than FD + SSP and FD (P < 0.05). Except for cadmium and manganese, the larval heavy metal concentration was below the legally permitted upper concentrations for feed. In conclusion, the SSR used could enrich BSFL with Ca and P but at the expense of growth. Due to the accumulation of Cd and Mn, BSFL or products thereof can only be a component of farmed animal feed whereas in BSFL frass heavy metal concentrations remained below the upper limit authorized by EU.

Genotype-dependent impact of dietary vitamin D3 on laying hens.

Vitamin D3 has an integral part in calcium and phosphorus homoeostasis, which in turn plays a key role in egg production of hens. The present study aimed to investigate whether an additional vitamin D3 supplementation improves the laying performance and egg quality of hens according to their genetic potential. For this purpose, four layer lines (low performing: R11 and L68; high performing: WLA and BLA) supplemented either with 300 or 3000 IU vitamin D3 per kg feed were compared concerning serum 25-hydroxyvitamin D3 (25-OHD3), calcium, phosphorus and alkaline phosphatase (ALP), laying performance and egg quality. The higher supplementation of vitamin D3 increased 25-OHD3 serum concentrations in all genotypes, except for R11 and WLA hens in week 49, and also elevated vitamin D3 and 25-OHD3 content in the egg yolk (p < 0.05). In week 29, 3000 IU vitamin D3 decreased pooled least squares means (LSMeans) of serum calcium concentrations considering all genotypes and increased the ALP concentrations in BLA hens (p < 0.05). Considering the whole experimental period daily egg mass of R11 hens was increased by an additional vitamin D3 supplementation (p < 0.001). Regarding all genotypes and the whole experimental period the pooled LSMeans of breaking strength of eggs from hens fed 3000 IU vitamin D3 were higher than those of hens fed 300 IU (p = 0.044). In conclusion, present results give evidence that the higher vitamin D3 supplementation might have genotype-dependently beneficial effects on calcium and phosphorus homoeostasis of hens, which might improve feed efficiency in the early laying period and promote the persistence of the laying period irrespectively of genotype. The increase of serum 25-OHD3 by the higher vitamin D supplementation supported the higher transfer of vitamin D in the egg yolk and improved genotype-dependently the breaking strength of the eggshell.

Changes of the liver metabolome following an intravenous lipopolysaccharide injection in Holstein cows supplemented with dietary carnitine.

BACKGROUND: Carnitine facilitates the flux of long-chain fatty acids for hepatic mitochondrial beta-oxidation, which acts to ameliorate the negative energy balance commonly affecting high-yielding dairy cows. Inflammation triggered by lipopolysaccharide (LPS) load can however pose a challenge to the metabolic integrity via the expression of pro-inflammatory mediators, leading to immune system activation and respective metabolic alterations. The effect of enhanced carnitine availability on hepatic metabolome profiles during an inflammatory challenge has not yet been determined in dairy cows. Herein, Holstein cows were supplemented with 25 g/d rumen-protected carnitine from 42 d prepartum until 126 d postpartum (n = 16) or assigned to the control group with no supplementation during the same period (n = 14). We biopsied the liver of the cows before (100 d postpartum) and after (112 d postpartum) an intravenous injection of 0.5 µg/kg LPS. Liver samples were subjected to a targeted metabolomics analysis using the AbsoluteIDQ p180 Kit (Biocrates Life Sciences AG, Innsbruck, Austria).  RESULTS: Multivariate statistical analyses revealed that hepatic metabolome profiles changed in relation to both the carnitine supplementation and the LPS challenge. Comparing the metabolite profiles on 100 d, carnitine increased the concentration of short- and long-chain acyl-carnitines, which may be explained by an enhanced mitochondrial fatty acid shuttle and hence greater energy availability. The LPS injection affected hepatic metabolite profiles only in the carnitine supplemented group, particularly altering the concentration of biogenic amines. CONCLUSIONS: Our results point to interactions between an acute hepatic inflammatory response and biogenic amine metabolism, depending on energy availability.

Dietary L-Carnitine Affects Leukocyte Count and Function in Dairy Cows Around Parturition.

In early lactation, an energy deficit leading to a negative energy balance (NEB) is associated with increased susceptibility to disease and has been shown to be an important factor during transition in dairy cows. L-carnitine as a key factor in the mitochondrial transport of fatty acids and subsequently for ß-oxidation and energy release is known to modulate mitochondrial biogenesis and thus influence metabolism and immune system. In the current study, we characterized hematological changes around parturition and investigated the potential effects of dietary L-carnitine supplementation on immune cell functions. For this approach, dairy cows were assigned either to a control (CON, n = 30) or an L-carnitine group [CAR, n = 29, 25 g rumen-protected L-carnitine per cow and day (d)]. Blood samples were taken from d 42 ante partum (ap) until d 110 post-partum (pp), with special focus and frequent sampling from 0.5 to72 h post-calving to clarify the impact of L-carnitine supplementation on leukocyte count, formation of reactive oxygen species (ROS) in polymorphonuclear cells (PMN) and peripheral mononuclear cells (PBMC) and their phagocytosis activity. Blood cortisol concentration and the capacity of PBMC proliferation was also investigated. All populations of leukocytes were changed during the peripartal period, especially granulocytes showed a characteristic increase up to 4 h pp. L-carnitine supplementation resulted in increased levels of eosinophils which was particularly pronounced one day before to 4 h pp, indicating a possible enhanced support for tissue repair and recovery. Non-supplemented cows showed a higher phagocytic activity in PBMC as well as a higher phagocytic capacity of PMN during the most demanding period around parturition, which may relate to a decrease in plasma levels of non-esterified fatty acids reported previously. L-carnitine, on the other hand, led to an increased efficiency to form ROS in stimulated PMN. Finally, a short period around calving proved to be a sensitive period in which L-carnitine administration was effective.

Microbiome Clusters Disclose Physiologic Variances in Dairy Cows Challenged by Calving and Lipopolysaccharides.

Dairy cows respond individually to stressful situations, even under similar feeding and housing conditions. The phenotypic responsiveness might trace back to their microbiome and its interactions with the host. This long-term study investigated the effects of calving, lipopolysaccharide (LPS)-induced inflammation, and l-carnitine supplementation on fecal bacteria and metabolites, dairy cow milk production, health, energy metabolism, and blood metabolites. Fifty-four multiparous Holstein dairy cows were examined over a defined period of life (168 days). The obtained data allowed a holistic analysis combining microbiome data such as 16S rRNA amplicon sequencing and fecal targeted metabolome (188 metabolites) with host parameters. The conducted analyses allowed the definition of three enterotype-like microbiome clusters in dairy cows which could be linked to the community diversity and dynamics over time. The microbiome clusters were discovered to be treatment independent, governed by Bifidobacterium (C-Bifi), unclassified (uncl.) Clostridiales (C-Clos), and unclassified Spirochaetaceae (C-Spiro). Animals between the clusters varied significantly in terms of illnesses, body weight, microbiome composition, and milk and blood parameters. C-Bifi animals were healthier and leaner with a less diverse but dynamic microbiome. C-Spiro animals were heavier, but the diversity of the static microbiome was higher. This pioneering study uncovered microbiome clusters in dairy cows, each contributing differently to animal health and productive performance and with a crucial role of Bifidobacterium. IMPORTANCE The health of dairy cows has to be carefully considered for sustainable and efficient animal production. The microbiome of animals plays an important role in the host's nutrient supply and regulation of immune functions. We show that a certain composition of the fecal microbiome, called microbiome clusters, can be linked to an animal's health at challenging life events such as calving and inflammation. Cows with a specific set of bacteria have coped better under these stressors than have others. This novel information has great potential for implementing microbiome clusters as a trait for sustainable breeding strategies.

Increased plasma and milk short-chain acylcarnitine concentrations reflect systemic LPS response in mid-lactation dairy cows.

Lipopolysaccharides (LPS) challenge the metabolic integrity of high-yielding dairy cows, activating the immune system and altering energy metabolism. Fatty acid oxidation, a major energy-gaining pathway, can be improved by supplementary carnitine, facilitating the transport of fatty acids into mitochondria. The metabolic response to the LPS challenge could alter both the plasma and the milk metabolome. Plasma and milk samples collected from cows treated with (n = 27) or without (n = 27) dietary carnitine, before and after intravenous administration of LPS, were subjected to a targeted metabolomics analysis. Multivariate statistical analyses revealed that both plasma and milk metabolome changed in response to the LPS challenge in both the carnitine-supplemented and the control cows. Short-chain acylcarnitines (carbon chain length C2, C3, C4, and C5) and long-chain acylcarnitines (C14, C16, and C18) had the highest performance to indicate LPS response when testing the predictive power of single metabolites using receiver-operator characteristics (ROC) analysis. The maximum area under a ROC curve (AUC) was 0.93. Biogenic amines, including sarcosine, and amino acids such as glutamine and isoleucine had AUC > 0.80 indicating metabolic changes due to the LPS challenge. In summary, the metabolites involved in the LPS response were acylcarnitines C2 and C5, sarcosine, glutamine, and isoleucine in plasma, and acylcarnitines C4 and C5 in milk. The interrelationship of plasma and milk metabolome included correlation of acylcarnitines C2, C4, and C5 between plasma and milk.

Effects of 3-nitrooxypropanol and varying concentrate feed proportions in the ration on methane emission, rumen fermentation and performance of periparturient dairy cows.

The climate-relevant enteric methane (CH4) formation represents a loss of feed energy that is potentially meaningful for energetically undersupplied peripartal dairy cows. Higher concentrate feed proportions (CFP) are known to reduce CH4 emissions in cows. The same applies to the feed additive 3-nitrooxypropanol (3-NOP), albeit through different mechanisms. It was hypothesised that the hydrogen not utilised for CH4 formation through the inhibition by 3-NOP would be sequestered by propionate formation triggered by higher CFP so that it could thereby give rise to a synergistically reduced CH4 emission. In a 2 × 2-factorial design, low (LC) or high (HC) CFP were either tested without supplements (CONLC, CONHC) or combined with 3-NOP (NOPLC, 48.4 mg/kg dry matter (DM); NOPHC, 51.2 mg 3-NOP/kg DM). These four rations were fed to a total of 55 Holstein cows from d 28 ante partum until d 120 post partum. DM intake (DMI) was not affected by 3-NOP but increased with CFP (CFP; p < 0.001). CH4/DMI and CH4/energy-corrected milk (ECM) were mitigated by 3-NOP (23% NOPLC, 33% NOPHC) (p < 0.001) and high CFP (12% CON, 22% 3-NOP groups) (CFP × TIME p < 0.001). Under the conditions of the present experiment, the CH4 emissions of NOPLC increased to the level of the CON groups from week 8 until the end of trial (3-NOP × CFP × TIME; p < 0.01). CO2 yield decreased by 3-NOP and high CFP (3-NOP × CFP; p < 0.001). The reduced body weight loss and feed efficiency in HC groups paralleled a more positive energy balance being most obvious in NOPHC (3-NOP × CFP; p < 0.001). ECM was lower for NOPHC compared to CONHC (3-NOP × CFP; p < 0.05), whereas LC groups did not differ. A decreased fat to protein ratio was observed in HC groups and, until week 6 post partum, in NOPLC. Milk lactose and urea increased by 3-NOP (3-NOP; p < 0.05). 3-NOP and high CFP changed rumen fermentation to a more propionic-metabolic profile (3-NOP; CFP; p < 0.01) but did not affect rumen pH. In conclusion, CH4 emission was synergistically reduced when high CFP was combined with 3-NOP while the CH4 mitigating 3-NOP effect decreased with progressing time when the supplement was added to the high-forage ration. The nature of these interactions needs to be clarified.

Dietary l-carnitine Supplementation Modifies the Lipopolysaccharide-Induced Acute Phase Reaction in Dairy Cows.

l-carnitine plays an important role in energy metabolism through supporting the transport of activated fatty acids to the subcellular site of ß-oxidation. An acute phase reaction (APR) is known as an energy consuming process. Lipopolysaccharides (LPS) are often used in animal models to study intervention measures during innate immune responses such as APR. Thus, the aim of the study was to investigate the effects of dietary l-carnitine supplementation during an LPS-induced APR in mid-lactating German Holstein cows. Animals were assigned to a control (CON, n = 26) or l-carnitine group (CAR, n = 27, 25 g rumen-protected l-carnitine/cow/d) and received an intravenous injection of LPS (0.5 µg/kg body weight) at day 111 post-partum. Blood samples were collected from day 1 pre-injection until day 14 post-injection (pi). From 0.5 h pi until 72 h pi blood samplings and clinical examinations were performed in short intervals. Clinical signs of the APR were not altered in group CAR except rumen motility which increased at a lower level compared to the CON group after a period of atonia. Group CAR maintained a higher insulin level compared to group CON even up to 72 h pi which might support glucose utilization following an APR.

Oral exposure of pigs to the mycotoxin deoxynivalenol does not modulate the hepatic albumin synthesis during a LPS-induced acute-phase reaction.

The sensitivity of pigs to deoxynivalenol (DON) might be influenced by systemic inflammation (SI) which impacts liver. Besides following acute-phase proteins, our aim was to investigate both the hepatic fractional albumin (ALB) synthesis rate (FSR) and the ALB concentration as indicators of ALB metabolism in presence and absence of SI induced by LPS via pre- or post-hepatic venous route. Each infusion group was pre-conditioned either with a control diet (CON, 0.12 mg DON/kg diet) or with a DON-contaminated diet (DON, 4.59 mg DON/kg diet) for 4 wk. A depression of ALB FSR was observed 195 min after LPS challenge, independent of feeding group or LPS application route, which was not paralleled by a down-regulated ALB mRNA expression but by a reduced availability of free cysteine. The drop in ALB FSR only partly explained the plasma ALB concentrations which were more depressed in the DON-pre-exposed groups, suggesting that ALB levels are influenced by further mechanisms. The abundances of haptoglobin, C-reactive protein, serum amyloid A, pig major acute-phase protein, fibrinogen and LPS-binding protein mRNA were up-regulated upon LPS stimulation but not accompanied by increases in the plasma concentrations of these proteins, pointing at an imbalance between synthesis and consumption.

Effects of a Dietary L-Carnitine Supplementation on Performance, Energy Metabolism and Recovery from Calving in Dairy Cows.

Dairy cows are metabolically challenged during the transition period. Furthermore, the process of parturition represents an energy-consuming process. The degree of negative energy balance and recovery from calving also depends on the efficiency of mitochondrial energy generation. At this point, L-carnitine plays an important role for the transfer of fatty acids to the site of their mitochondrial utilisation. A control (n = 30) and an L-carnitine group (n = 29, 25 g rumen-protected L-carnitine per cow and day) were created and blood samples were taken from day 42 ante partum (ap) until day 110 post-partum (pp) to clarify the impact of L-carnitine supplementation on dairy cows, especially during the transition period and early puerperium. Blood and clinical parameters were recorded in high resolution from 0.5 h to 72 h pp. L-carnitine-supplemented cows had higher amounts of milk fat in early lactation and higher triacylglyceride concentrations in plasma ap, indicating increased efficiency of fat oxidation. However, neither recovery from calving nor energy balance and lipomobilisation were influenced by L-carnitine.

Gain and loss of subcutaneous and abdominal fat depot mass from late pregnancy to 100 days in milk in German Holsteins.

This research paper addresses the hypothesis that in times of negative energy balance around parturition in dairy cattle, lipids stored in adipocytes are mobilised in a more intensive manner out of the abdominal depots than out of the subcutaneous adipose tissues. Furthermore, the impact of niacin supplementation and energy density of the ration on adipose tissue mass gain and loss was assessed. Absolute masses of subcutaneous (SCAT), retroperitoneal (RPAT), omental (OMAT), mesenterial (MAT) and abdominal adipose tissue as a whole (AAT) were estimated by ultrasonography at -42, 3, 21 and 100 DIM. Absolute and relative daily gain during dry period (-42 to 3 DIM) and loss in fresh cow period (3 to 21 DIM) and early lactation period (22 to 100 DIM) were calculated. Feeding regime neither by niacin nor by energy density exerted any effect on adipose tissue masses. The AAT was always bigger than SCAT, but RPAT, OMAT and MAT did not differ amongst each other. All depot masses showed similar patterns with an increase during dry period and a decrease after calving. In fresh cow period AAT absolutely and relatively lost more mass than SCAT. This confirms that AAT is more intensively mobilised than SCAT during that time span. Further absolute daily gain during dry period was strongly negatively correlated with absolute daily loss during fresh cow period. This underlines the impact of individual body condition on adipose mobilisation in periparturient dairy cows. According to these results, it has to be taken into account that the largest amount of fat mobilised in the fresh cow period origins from AAT. This might impact the pattern of adipose derived metabolites and metabolic effectors interacting in physiological and deregulated adaptation to negative energy balance.

Fine grinding or expanding of feed as pre-treatment for pelleting in dependence on dietary rapeseed expeller proportion: Nutritional consequences for broilers.

Although commercial broiler feed is usually differently conditioned before pelleting, the nutritional consequences of fine grinding or expanding as pre-pelleting treatments are poorly defined so far. Therefore, the effects of these two pre-treatments on nutrient digestibility, broiler performance and digestive tract of broilers were tested. In order to investigate possible interactions between pre-treatments and diet composition two diets differing in rapeseed expeller proportion were tested in a two by two factorial design. Thus, four diets were designed including two diets containing 6% rapeseed expeller (RSE) which were pre-treated by fine grinding (6%FgP) or expanding (6%ExP), and two corresponding diets containing 12% RSE (12%FgP and 12%ExP). For the experiments, 864 male broilers were used. There was a significant diet-by-technical feed treatment (TFT) interaction in case of the digestibility of all considered crude nutrients (p < 0.05). Diet 6%ExP showed higher crude protein digestibility compared to other feeds (p < 0.001). The highest digestibility of organic matter, ether extract, crude fibre and N-free extractives achieved diet 12%FgP. Diets 6%ExP and 12%FgP showed higher N-corrected metabolisable energy content (p < 0.001). TFT affected daily feed intake (DFI) and body weight (BW) gain in a diet-dependent manner (p < 0.001). Feeding of 6%FgP enhanced DFI and BW gain compared to other feeds but 6%ExP reduced both parameters (p < 0.001). Weights of proventriculi and gizzards of animals fed 6%ExP were increased compared with 6%FgP (p < 0.01). In contrast, proventricular length in animals fed 6%FgP was increased compared with diet 6%ExP (p = 0.042). Moreover, animals fed 6%FgP had wider proventriculi than animals fed 12%FgP (p = 0.023). Feed 6%ExP increased proventricular weight compared to 12%ExP (p = 0.001). With regard to the strong relationships between diet and TFT no specific processing method can be recommended according to considered nutritional aspects. A marked prevention of proventricular dilatation due to pellet feeding could not be realised by various used TFT or feed formulations. Used amounts of RSE had no obvious adverse effects on considered nutritional aspects.

Suitability of n-alkanes and chromium (III) oxide as digestibility markers in calves at the end of the milk feeding period supplemented with a prebiotic.

Prebiotics reveal positive effects on the growth performance of pigs and poultry, and might influence intestinal microflora. This, in consequence, could alter recovery rates of digestibility markers. In the current study, we evaluated the suitability of chromium (III) oxide (Cr2O3) and the synthetic alkanes n-dotriacontane (C32) and n-hexatriacontane (C36) as external markers for digestibility estimation compared with the standard total collection method in calves supplemented with galacto-oligosaccharides. Eight male German Holstein calves (average age ± SD = 57 ± 8 days) were divided into 2 milk replacer feeding groups (group receiving galacto-oligosaccharides [A] and control group [B]). Each of 2 groups of 4 individually fed calves received a distinct milk replacer with added markers for 14 days. They were fed twice daily restrictively with milk replacer, concentrate and hay. After an adaptation period of 10 days, total faeces were collected. Faecal marker recoveries (FMR, means ± SD) for C32 were (72 ± 14)% for A and (80 ± 12)% for B. Faecal marker recoveries for C36 was (82 ± 15)% and (88 ± 13)% for groups A and B, respectively. The FMR for Cr2O3 was (102 ± 11)% and (100 ± 1)% for groups A and B, respectively. There were no significant differences between total collection organic matter digestibility and marker based organic matter digestibility when using Cr2O3 and C36. But, when utilizing C32 to calculate nutrient digestibilities, results differed from the total collection method for organic matter, crude protein and ether extract. The results indicate that Cr2O3 and C36 can be applied in digestibility studies with calves and give accurate estimates for OM and nutrient digestibilities without correction for FMR.

Biomarker Evaluation and Toxic Effects of an Acute Oral and Systemic Fumonisin Exposure of Pigs with a Special Focus on Dietary Fumonisin Esterase Supplementation.

The mycotoxin fumonisin B1 (FB1) is a frequent contaminant of feed. It causes a disruption of sphingolipid metabolism and pulmonary, hepatic, and immunological lesions in pigs depending on the exposure scenario. One sensitive biomarker for FB1 exposure is the sphinganine (Sa) to sphingosine (So) ratio in blood. The fumonisin esterase FumD, which can be used as a feed additive, converts FB1 into the much less toxic metabolite hydrolyzed FB1 (HFB1). We conducted a single-dose study with barrows allocated to one of five treatments: (1) control (feed, 0.9% NaCl intravenously iv), (2) 139 nmol FB1 or (3) HFB1/kg BW iv, (4) 3425 nmol FB1/kg BW orally (po), or (5) 3321 nmol FB1/kg BW and 240 U FumD/kg feed po. The Sa/So ratio of iv and po FB1 administered groups was significantly elevated in blood and Liquor cerebrospinalis, but no fumonisin-associated differences were reflected in other endpoints. Neither clinical lung affections nor histopathological pulmonary lesions were detected in either group, while some parameters of hematology and clinical biochemistry showed a treatment⁻time interaction. FumD application resulted in Sa/So ratios comparable to the control, indicating that the enzymatic treatment was effectively preventing the fumonisin-induced disruption of sphingolipid metabolism.

Effect of vitamin E supplementation in milk replacer and Shiga toxoid vaccination on serum α-tocopherol, performance, haematology and blood chemistry in male Holstein calves.

Vitamin E (vit E), an essential antioxidant for maintaining the stability of biological membranes and the function of the immune system, is considered to support adaptive immune responses and performance in cattle. The principal virulence factor of Shiga toxin (Stx)-producing Escherichia coli (STEC), the eponymous Stx, modulates cellular immune responses in cattle, the primary STEC reservoir. Active and passive immunization of calves with Shiga toxoids (rStxMUT ) was recently shown to reduce the STEC shedding. Here, we examined the influence of vit E on calves' serum α-tocopherol, performance, haematology, blood chemistry and its interaction with rStxMUT immunization. Data from calves having received passive (colostrum from immunized cows) and active (intramuscularly at 5th and 8th weeks of life) vaccination with rStxMUT (n = 24) were compared to unvaccinated controls (n = 24; fed with low anti-Stx colostrum, placebo injected). For each vaccination group, data were analysed according to the level of vit E supplementation offered by milk replacer (188 IU all-rac-α-tocopheryl acetate daily [VitEM ] vs. 354 IU [VitEH ]). An increase by 79% in daily vit E supplementation led to slightly higher serum α-tocopherol level and earlier concentrate intake at the beginning of the experiment without significant differences in live weight gain, haematology, blood chemistry parameters and peripheral CD4+ and CD8+ T-cell subpopulations. rStxMUT vaccination modulated the CD4+ /CD8+ ratio irrespective of vit E supplementation but decreased concentrate intake in VitEH in a time-dependent manner. Results of our study indicate that an increase in daily vit E supplementation vastly fails to exert effects on laboratory parameters and growth performance. However, observed interactive effects of vit E supply and vaccination on the regulation of feed intake deserves further attention.

Influence of vitamin E on organic matter fermentation, ruminal protein and fatty acid metabolism, protozoa concentrations and transfer of fatty acids.

Vitamin E (Vit. E) is discussed to influence ruminal biohydrogenation. The objective of this study was to investigate the influence of a Vit. E supplementation on rumen fermentation characteristics, ruminal microbial protein synthesis as well as ruminal organic matter fermentation. Furthermore, we aimed to investigate the influence of Vit. E supplementation on short-chain fatty acids (SCFA) and protozoa concentrations in the rumen and, in addition, on transfer rates of middle-chain and long-chain fatty acids into the duodenum in lactating dairy cows. Eight rumen and duodenum fistulated German Holstein cows were assigned to either a group receiving 2,327 IU/d Vit. E (138.6 IU/kg DM DL-α-tocopherylacetate; n = 4) or a control group (23.1 IU/kg DM; n = 4). Neither ruminal protein synthesis nor organic matter fermentation was influenced by treatment. Vit. E did not act on the concentrations of short-chain fatty acids and protozoa in rumen fluid. Duodenal flow of C13:0 (1.3 versus 0.2 g/d, p = 0.014) and iso-C14:0 (1.0 versus 0.5 g/d, p = 0.050) was higher in the Vit. E group. We observed a trend for higher duodenal flows for C12:0 (1.6 versus 0.9 g/d, p = 0.095) and anteiso-C15:0 (12.2 versus 8.9 g/d, p = 0.084). Transfer rate of C12:0 tended to be higher in the Vit. E group (125.61 versus 73.96, p = 0.082). No other transfer rates were affected by treatment. Further studies are necessary to investigate the influence of Vit. E on rumen microbiota and their fatty acid production as well as on the impact of different doses of Vit. E supplementation on variables of protein synthesis efficiency.

Decreased STEC shedding by cattle following passive and active vaccination based on recombinant Escherichia coli Shiga toxoids.

The principal virulence factor of Shiga toxin (Stx)-producing Escherichia coli (STEC), the eponymous Stx, modulates cellular immune responses in cattle, the primary STEC reservoir. We examined whether immunization with genetically inactivated recombinant Shiga toxoids (rStx1MUT/rStx2MUT) influences STEC shedding in a calf cohort. A group of 24 calves was passively (colostrum from immunized cows) and actively (intra-muscularly at 5th and 8th week) vaccinated. Twenty-four calves served as unvaccinated controls (fed with low anti-Stx colostrum, placebo injected). Each group was divided according to the vitamin E concentration they received by milk replacer (moderate and high supplemented). The effective transfer of Stx-neutralizing antibodies from dams to calves via colostrum was confirmed by Vero cell assay. Serum antibody titers in calves differed significantly between the vaccinated and the control group until the 16th week of life. Using the expression of activation marker CD25 on CD4+CD45RO+ cells and CD8αhiCD45RO+ cells as flow cytometry based read-out, cells from vaccinated animals responded more pronounced than those of control calves to lysates of STEC and E. coli strains isolated from the farm as well as to rStx2MUT in the 16th week. Summarized for the entire observation period, less fecal samples from vaccinated calves were stx1 and/or stx2 positive than samples from control animals when calves were fed a moderate amount of vitamin E. This study provides first evidence, that transfer to and induction in young calves of Stx-neutralizing antibodies by Shiga toxoid vaccination offers the opportunity to reduce the incidence of stx-positive fecal samples in a calf cohort.

Effects of dietary CLA supplementation, parity and different concentrate levels before calving on immunoglobulin G1, G2 and M concentrations in dairy cows.

Peripartal dairy cows exhibit a higher susceptibility for infectious diseases, which might be linked to the negative energy balance occurring at the onset of lactation. A dietary supplementation of conjugated linoleic acids (CLA) may reduce milk fat yield and subsequently lower the energy deficit. The utilization of immunoglobulins (Ig) for colostrogenesis might impair humoral immunity in peripartal dairy cows; therefore this study investigated the effects of a CLA supplement, parity and different dietary energy levels on plasma and colostrum IgG1, IgG2 and IgM levels in dairy cows and their calves. Blood samples were collected from 64 cows from 21days before until 56days after parturition and colostrum samples for the first 3days of lactation. Plasma immunoglobulin concentrations of 19 calves were determined before colostrum uptake. Neither plasma IgG1, nor IgG2 levels were affected by CLA or dietary energy level. However, immunoglobulin levels were affected by parity. Heifers possessed the lowest IgG1 concentrations. IgG2 concentrations were highest in cows with 2 lactations prior to parturition and in heifers after parturition. Plasma IgM levels were characterized by a sharp decrease 3days prior to parturition and were scarcely affected by the feeding regimen or parity. Generally, immunoglobulin levels appear to be mostly independent from the peripartal energy balance of the cows and are not influenced by dietary CLA. However, pronounced differences among parities for IgG1 and IgG2 were revealed which should be further evaluated.