Helga Sauerwein | Rheinische Friedrich-Wilhelms-Universität Bonn (original) (raw)
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Papers by Helga Sauerwein
Archives of Animal Nutrition, 2015
Diet change and fatness are supposed to challenge the immune system of the cow. Therefore, immuno... more Diet change and fatness are supposed to challenge the immune system of the cow. Therefore, immunological and haematological consequences of adaptation to and continued feeding of a high-energy diet were studied in eight non-pregnant, non-lactating Holstein cows over 16 weeks. Blood haptoglobin concentration remained unaltered, suggesting that an acute phase reaction was not induced. Stimulation ability of peripheral blood mononuclear cells and stimulated oxidative burst capacity of granulocytes increased significantly in the course of the experiment after an initial drop. While total leucocyte counts increased, the proportion of granulocytes increased and that of lymphocytes decreased at the same time as the ratio of CD4(+)/CD8(+) lymphocytes did. Capability of rumen microbes to detoxify the immune-modulating mycotoxin deoxynivalenol (DON) was not compromised as indicated by the exclusive presence of de-DON as the detoxified DON metabolite in blood. In conclusion, both diet change and prolonged positive energy balance influenced the bovine immune system.
ABSTRACT Abstract Text: Adipose tissue (AT) secretes adipokines regulating both metabolism and im... more ABSTRACT Abstract Text: Adipose tissue (AT) secretes adipokines regulating both metabolism and immune function. In monogastrics, diet-induced obesity is associated with changing adipokine profiles and increased macrophage (Ms) infiltration. However, in early lactating dairy cows we found virtually no Ms infiltration in different AT depots; non-lactating overconditioned heifers had increased accumulation of Ms in AT related with larger adipocytes, albeit in low total numbers. We hypothesized that the portion of Ms in bovine AT will remain small, even if fat is excessively accumulated in short time. Therefore we aimed to investigate the Ms infiltration in subcutaneous (sc)AT after rapid, diet-induced fat accumulation in cows. Eight non-pregnant, non-lactating pluriparous German Holstein cows, were adapted to diets with increasing concentrate feed proportions (from 0 to 60% of total dry matter intake) during the first 6 weeks of the experiment which was maintained for 9 weeks at 60% concentrate feeding. The body condition score (5-point-scale) increased from 2.31 ± 0.12 to 4.53 ± 0.14 and the body weight increased from 540 ± 20 kg to 792 ± 29 kg. Three biopsies were taken every 8 weeks of the entire experimental period from scAT of the tailhead region. Immunohistochemistry was performed on cryosections (12 µm) using the Ms-specific marker CD68. Bovine lymph nodes were used for positive and negative controls. The number of Ms and adipocytes per mm² were counted (100-fold magnification; 10 fields per sample). The portion of Ms was calculated from the mean number of positive stained cells/mean number of total adipocytes x 100. In total, 12 out of 23 samples yielded CD68-positive stainings. Considering the different time points, 5 out of 7, 5 out of 8 and 2 out of 8 samples were Ms-positive at the beginning, the middle and the end of the experiment, respectively. However, the average portion of Ms was only marginal: 3.7 ± 3.0% (n=7) at the beginning, 0.9 ± 0.3% (n=8) at the middle and 0.5 ± 0.3% (n=8) at the end of the experiment. Thus even a rapid and pronounced increase of fat mass was not accompanied by Ms infiltration into subcutaneous AT. In consideration of the virtual absence of Ms in AT in earlier studies about cows during the first weeks of lactation, and the low portion of Ms in overconditioned heifers and in the present study, we assume that Ms infiltration is of no importance for bovine AT. Keywords: macrophages, adipose tissue, cow
Several investigations have shown that a wide range of chemicals, present in the environment is c... more Several investigations have shown that a wide range of chemicals, present in the environment is capable to interact with the endocrine system. Also the natural and synthetic steroids which are excreted by humans and domestic animals might act as endocrine disrupters. For effect related analysis of androgenic substances we developed an androgen receptor assay by using recombinant human androgen receptor
Journal of Animal Science
ABSTRACT
Journal of Nutrition
Postprandial insulin resistance with excessive hyperinsulinemia, hyperglycemia and glucosuria dev... more Postprandial insulin resistance with excessive hyperinsulinemia, hyperglycemia and glucosuria develops with increasing age in veal calves intensively fed milk replacers. We tested the age dependency of insulin resistance, modulated by high lactose intake, glucose oxidation and insulin receptor number and affinity after an overnight period without food. Male calves were fed a milk replacer containing 290 or 423 g lactose and 310 and 541 g total sugar/kg from 69-195 kg body weight. At mean body weights of 95 and 170 kg, insulin-dependent glucose metabolism was studied in euglycemic-hyperinsulinemic glucose clamps (EGC), and glucose-dependent insulin responses were tested in hyperglycemic clamps (HGC). EGC were combined with infusions of [ 13 C 6 ]glucose to measure glucose kinetics and glucose oxidation by determination of 13 CO 2 exhalation. During EGC and HGC, insulin concentrations were similar in both groups, indicating comparable insulin secretion and metabolic clearance rates. On the basis of glucose infusion rates required to maintain eu-or hyperglycemia in EGC and HGC, respectively, insulin-dependent glucose utilization was not age dependent. However, in calves receiving a high lactose intake, insulin-dependent glucose utilization was enhanced in the early phases, but was reduced in the late stages of the growth trial. Insulin-dependent glucose utilization behaved inversely with atom % excess of [ 13 C 6 ]glucose, but changed in a manner similar to that of the rate of glucose appearance. Inhibition of endogenous glucose output, exhalation of 13 CO 2 and amounts of oxidized glucose exhibited no group differences. More glucose was therefore stored in lactose-supplemented calves. A reduced insulin receptor number in skeletal muscle in calves fed high amounts of lactose likely contributed to low insulin-dependent glucose utilization.
Veterinární medicína
ABSTRACT
26 Simmental steers were randomly allocated to three different feeding groups. Up to 220 kg of li... more 26 Simmental steers were randomly allocated to three different feeding groups. Up to 220 kg of live weight all steers were kept under the same conditions, they were all castrated at 4 to 5 months of age. With 220 kg, 18 animals were transferred onto pasture feeding, the remaining 8 animals were fed as it is usual in common fattening systems (I). Having reached 500 kg live weight, the group kept on pasture was partitioned: 9 animals were further kept as before (P), the other 9 steers were transferred to the more intensive feeding regimen (C) to include the aspects of compensatory growth. The nutrient intakes as well as the growth rates and carcass composition of the different groups during the last fattening period (500 to 580 kg) is summarized in table 1. Animals were slaughtered at 570±12.5 kg and samples were collected from liver, heart, kidney and 4 muscles: m. splenius (SP), m. soleus (SO), m. cutaneus truncii (CT) and m. semispinalis capitis (SC), which were selected in order to represent maximal differences in fiber composition as well as in growth impetus.
DTW. Deutsche tierärztliche Wochenschrift
The Journal of Steroid Biochemistry and Molecular Biology
DTW. Deutsche tierärztliche Wochenschrift
Archives of Animal Nutrition, 2015
Diet change and fatness are supposed to challenge the immune system of the cow. Therefore, immuno... more Diet change and fatness are supposed to challenge the immune system of the cow. Therefore, immunological and haematological consequences of adaptation to and continued feeding of a high-energy diet were studied in eight non-pregnant, non-lactating Holstein cows over 16 weeks. Blood haptoglobin concentration remained unaltered, suggesting that an acute phase reaction was not induced. Stimulation ability of peripheral blood mononuclear cells and stimulated oxidative burst capacity of granulocytes increased significantly in the course of the experiment after an initial drop. While total leucocyte counts increased, the proportion of granulocytes increased and that of lymphocytes decreased at the same time as the ratio of CD4(+)/CD8(+) lymphocytes did. Capability of rumen microbes to detoxify the immune-modulating mycotoxin deoxynivalenol (DON) was not compromised as indicated by the exclusive presence of de-DON as the detoxified DON metabolite in blood. In conclusion, both diet change and prolonged positive energy balance influenced the bovine immune system.
ABSTRACT Abstract Text: Adipose tissue (AT) secretes adipokines regulating both metabolism and im... more ABSTRACT Abstract Text: Adipose tissue (AT) secretes adipokines regulating both metabolism and immune function. In monogastrics, diet-induced obesity is associated with changing adipokine profiles and increased macrophage (Ms) infiltration. However, in early lactating dairy cows we found virtually no Ms infiltration in different AT depots; non-lactating overconditioned heifers had increased accumulation of Ms in AT related with larger adipocytes, albeit in low total numbers. We hypothesized that the portion of Ms in bovine AT will remain small, even if fat is excessively accumulated in short time. Therefore we aimed to investigate the Ms infiltration in subcutaneous (sc)AT after rapid, diet-induced fat accumulation in cows. Eight non-pregnant, non-lactating pluriparous German Holstein cows, were adapted to diets with increasing concentrate feed proportions (from 0 to 60% of total dry matter intake) during the first 6 weeks of the experiment which was maintained for 9 weeks at 60% concentrate feeding. The body condition score (5-point-scale) increased from 2.31 ± 0.12 to 4.53 ± 0.14 and the body weight increased from 540 ± 20 kg to 792 ± 29 kg. Three biopsies were taken every 8 weeks of the entire experimental period from scAT of the tailhead region. Immunohistochemistry was performed on cryosections (12 µm) using the Ms-specific marker CD68. Bovine lymph nodes were used for positive and negative controls. The number of Ms and adipocytes per mm² were counted (100-fold magnification; 10 fields per sample). The portion of Ms was calculated from the mean number of positive stained cells/mean number of total adipocytes x 100. In total, 12 out of 23 samples yielded CD68-positive stainings. Considering the different time points, 5 out of 7, 5 out of 8 and 2 out of 8 samples were Ms-positive at the beginning, the middle and the end of the experiment, respectively. However, the average portion of Ms was only marginal: 3.7 ± 3.0% (n=7) at the beginning, 0.9 ± 0.3% (n=8) at the middle and 0.5 ± 0.3% (n=8) at the end of the experiment. Thus even a rapid and pronounced increase of fat mass was not accompanied by Ms infiltration into subcutaneous AT. In consideration of the virtual absence of Ms in AT in earlier studies about cows during the first weeks of lactation, and the low portion of Ms in overconditioned heifers and in the present study, we assume that Ms infiltration is of no importance for bovine AT. Keywords: macrophages, adipose tissue, cow
Several investigations have shown that a wide range of chemicals, present in the environment is c... more Several investigations have shown that a wide range of chemicals, present in the environment is capable to interact with the endocrine system. Also the natural and synthetic steroids which are excreted by humans and domestic animals might act as endocrine disrupters. For effect related analysis of androgenic substances we developed an androgen receptor assay by using recombinant human androgen receptor
Journal of Animal Science
ABSTRACT
Journal of Nutrition
Postprandial insulin resistance with excessive hyperinsulinemia, hyperglycemia and glucosuria dev... more Postprandial insulin resistance with excessive hyperinsulinemia, hyperglycemia and glucosuria develops with increasing age in veal calves intensively fed milk replacers. We tested the age dependency of insulin resistance, modulated by high lactose intake, glucose oxidation and insulin receptor number and affinity after an overnight period without food. Male calves were fed a milk replacer containing 290 or 423 g lactose and 310 and 541 g total sugar/kg from 69-195 kg body weight. At mean body weights of 95 and 170 kg, insulin-dependent glucose metabolism was studied in euglycemic-hyperinsulinemic glucose clamps (EGC), and glucose-dependent insulin responses were tested in hyperglycemic clamps (HGC). EGC were combined with infusions of [ 13 C 6 ]glucose to measure glucose kinetics and glucose oxidation by determination of 13 CO 2 exhalation. During EGC and HGC, insulin concentrations were similar in both groups, indicating comparable insulin secretion and metabolic clearance rates. On the basis of glucose infusion rates required to maintain eu-or hyperglycemia in EGC and HGC, respectively, insulin-dependent glucose utilization was not age dependent. However, in calves receiving a high lactose intake, insulin-dependent glucose utilization was enhanced in the early phases, but was reduced in the late stages of the growth trial. Insulin-dependent glucose utilization behaved inversely with atom % excess of [ 13 C 6 ]glucose, but changed in a manner similar to that of the rate of glucose appearance. Inhibition of endogenous glucose output, exhalation of 13 CO 2 and amounts of oxidized glucose exhibited no group differences. More glucose was therefore stored in lactose-supplemented calves. A reduced insulin receptor number in skeletal muscle in calves fed high amounts of lactose likely contributed to low insulin-dependent glucose utilization.
Veterinární medicína
ABSTRACT
26 Simmental steers were randomly allocated to three different feeding groups. Up to 220 kg of li... more 26 Simmental steers were randomly allocated to three different feeding groups. Up to 220 kg of live weight all steers were kept under the same conditions, they were all castrated at 4 to 5 months of age. With 220 kg, 18 animals were transferred onto pasture feeding, the remaining 8 animals were fed as it is usual in common fattening systems (I). Having reached 500 kg live weight, the group kept on pasture was partitioned: 9 animals were further kept as before (P), the other 9 steers were transferred to the more intensive feeding regimen (C) to include the aspects of compensatory growth. The nutrient intakes as well as the growth rates and carcass composition of the different groups during the last fattening period (500 to 580 kg) is summarized in table 1. Animals were slaughtered at 570±12.5 kg and samples were collected from liver, heart, kidney and 4 muscles: m. splenius (SP), m. soleus (SO), m. cutaneus truncii (CT) and m. semispinalis capitis (SC), which were selected in order to represent maximal differences in fiber composition as well as in growth impetus.
DTW. Deutsche tierärztliche Wochenschrift
The Journal of Steroid Biochemistry and Molecular Biology
DTW. Deutsche tierärztliche Wochenschrift