Eduardo Schmitt

Overfeeding Dairy Cattle During Late-Pregnancy Alters Hepatic PPARα-Regulated Pathways Including Hepatokines: Impact on Metabolism and Peripheral Insulin Sensitivity

Hepatic metabolic gene networks were studied in dairy cattle fed control (CON, 1.34 Mcal/kg) or higher energy (overfed (OVE), 1.62 Mcal/kg) diets during the last 45 days of pregnancy. A total of 57 target genes encompassing PPARα-targets/co-regulators, hepatokines, growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis, lipogenesis, and lipoprotein metabolism were evaluated on −14, 7, 14, and 30 days around parturition. OVE versus CON cows were in more negative energy balance (NEB) postpartum and had greater serum non-esterified fatty acids (NEFA), β-hydroxybutyrate (BHBA), and liver triacylglycerol (TAG) concentrations. Milk synthesis rate did not differ. Liver from OVE cows responded to postpartal NEB by up-regulating expression of PPARα-targets in the fatty acid oxidation and ketogenesis pathways, along with gluconeogenic genes. Hepatokines (fibroblast growth factor 21 (FGF21), angiopoietin-like 4 (ANGPTL4)) and apolipoprotein A-V (APOA5) were up-regulated postpartum to a greater extent in OVE than CON. OVE led to greater blood insulin prepartum, lower NEFA:insulin, and greater lipogenic gene expression suggesting insulin sensitivity was not impaired. A lack of change in APOB, MTTP, and PNPLA3 coupled with upregulation of PLIN2 postpartum in cows fed OVE contributed to TAG accumulation. Postpartal responses in NEFA and FGF21 with OVE support a role of this hepatokine in diminishing adipose insulin sensitivity.

Associations between resumption of postpartum ovarian activity, uterine health and concentrations of metabolites and acute phase proteins during the transition period in Holstein cows

The resumption of ovarian activity, uterine health, severity of the negative energy balance and the synthesis of inflammatory mediators during the transition period in dairy cows are interrelated. Therefore, the aim of this study was to evaluate the association between the resumption of postpartum ovarian activity and the percentage of polymorphonuclear (PMN) cells in endometrial cytology, lipid mobilization and the secretion of acute phase proteins. For this study, 20 multiparous Holstein cows were used. Blood samples that were collected from 21d before calving to 44d in milk (DIM) were analyzed for serum glucose, non-esterified fatty acids (NEFA), insulin, haptoglobin, albumin, paraoxonase and progesterone. Endometrial cytology was performed at 37±2DIM to evaluate the percentage of PMN cells in the uterine flushing. Cows were divided into two groups: (1) ovulatory cows (n=12), which returned to ovarian activity by 44±2DIM; and (2) anovulatory cows (n=8), which did not resume ovarian activity during this period. Ovulatory cows had a lower (P=0.05) percentage of PMN cells in endometrial cytology than anovulatory cows (26.3±8.3% vs. 53.4±16.9%, respectively). Ovulatory cows had higher serum albumin during the pre- (P=0.03) and postpartum periods (P=0.01), and tended to have lower haptoglobin concentrations in the prepartum period (P=0.07) and higher paraoxonase activity in the postpartum period (P=0.09). In conclusion, cows that resumed ovarian activity early in the postpartum period had higher albumin concentrations in the peripartum period, which were associated with a lower percentage of uterine PMN cells.

Dietary Lipid During Late-Pregnancy and Early-Lactation to Manipulate Metabolic and Inflammatory Gene Network Expression in Dairy Cattle Liver with a Focus on PPARs

Polyunsaturated (PUFA) long-chain fatty acids (LCFAs) are more potent in eliciting molecular and tissue functional changes in monogastrics than saturated LCFA. From −21 through 10 days relative to parturition dairy cows were fed no supplemental LCFA (control), saturated LCFA (SFAT; mainly 16:0 and 18:0), or fish oil (FISH; high-PUFA). Twenty-seven genes were measured via quantitative RT-PCR in liver tissue on day −14 and day 10. Expression of nuclear receptor co-activators (CARM1, MED1), LCFA metabolism (ACSL1, SCD, ACOX1), and inflammation (IL6, TBK1, IKBKE) genes was lower with SFAT than control on day −14. Expression of SCD, however, was markedly lower with FISH than control or SFAT on both −14 and 10 days. FISH led to further decreases in expression on day 10 of LCFA metabolism (CD36, PLIN2, ACSL1, ACOX1), intracellular energy (UCP2, STK11, PRKAA1), de novo cholesterol synthesis (SREBF2), inflammation (IL6, TBK1, IKBKE), and nuclear receptor signaling genes (PPARD, MED1, NRIP1). No change in expression was observed for PPARA and RXRA. The increase of DGAT2, PLIN2, ACSL1, and ACOX1 on day 10 versus −14 in cows fed SFAT suggested upregulation of both beta-oxidation and lipid droplet (LD) formation. However, liver triacylglycerol concentration was similar among treatments. The hepatokine FGF21 and the gluconeogenic genes PC and PCK1 increased markedly on day 10 versus −14 only in controls. At the levels supplemented, the change in the profile of metabolic genes after parturition in cows fed saturated fat suggested a greater capacity for uptake of fatty acids and intracellular handling without excessive storage of LD.

Hepatic purinergic signaling gene network expression and its relationship with inflammation and oxidative stress biomarkers in blood from peripartal dairy cattle

The liver plays a central role in allowing dairy cattle to make a successful transition into lactation. In liver, as in other tissues, extracellular nucleotides and nucleosides trigger cellular responses through adenosine and ATP receptors. Adenosine triphosphate and certain nucleotides serve as signals that can heighten purinergic receptor activation in several pathologic processes. We evaluated the mRNA expression of genes associated with the purinergic signaling network in liver tissue during the peripartal period. Seven multiparous Holstein cows were dried off at d -50 relative to expected parturition and fed a controlled-energy diet (net energy for lactation=1.24 Mcal/kg of DM) for ad libitum intake during the entire dry period. After calving, all cows were fed a common lactation diet (net energy for lactation=1.65 Mcal/kg of DM) until 30 DIM. Biopsies of liver were harvested at d -10, 7, and 21 for mRNA expression of 9 purinergic receptors, 7 ATP and adenosine transport channels, and 10 enzymes associated with ATP hydrolysis. Blood collected at d -21, -10, 7, 14, and 21 was used to measure concentrations of inflammation and oxidative stress biomarkers. The expression of type 1 purinergic receptors (ADORA2A and ADORA3), several nucleoside hydrolases [ectonucleoside triphosphate diphosphohydrolase 7 (ENTPD7), ectonucleotide pyrophosphatase/phosphodiesterase 2 (ENPP2), ENPP3, and adenosine deaminase (ADA)], and a type 2 purinergic receptor (P2RX7) was downregulated after calving. In contrast, the expression of type 2 purinergic receptors (P2RX4 and PR2Y11), an ATP release channel (gap junction hemichannel GJB1), and an adenosine uptake protein (SLC29A1) followed the opposite response, increasing after calving and remaining elevated through 21 d. Haptoglobin, ceruloplasmin, and reactive oxygen metabolite concentrations increased gradually from d -21 d through at least d 7. The opposite response was observed for albumin, paraoxonase, α-tocopherol, and nitric oxide, which decreased gradually to a nadir at 7 and 14 d. Our results suggest that alterations after calving of the expression of hepatic purinergic signaling genes could be functionally important because in nonruminants, they play roles in bile formation, glucose metabolism, cholesterol uptake, inflammation, and steatosis. The correlation analysis provided evidence of a link between purinergic signaling genes and biomarkers of inflammation and oxidative stress.

Correlação entre cálcio e insulina durante o teste de tolerância à glicose em ovelhas gestantes e não gestantes

Compararam-se as concentracoes de calcio, glicose e insulina em ovelhas gestantes e nao gestantes submetidas ao teste de tolerância a glicose (TTG). Oito ovelhas gestantes (GG) e oito nao gestantes (NG) foram submetidas ao TTG por meio da administracao endovenosa de uma solucao de glicose, na dose de 500mg/kg de peso vivo. Amostras de sangue foram coletadas nos tempos de -15, zero, 15, 30, 45, 60, 90, 120, 150 e 180 minutos, sendo zero min o momento da infusao, para avaliacao da concentracao sanguinea de glicose, calcio e insulina. Foi avaliada a taxa de metabolizacao de glicose e insulina, por meio do calculo da area sob a curva (ASC). As concentracoes de glicose, calcio, insulina e a ASC da insulina nao diferiram entre os grupos (P>0,05), entretanto as tres ultimas ASCs da glicose foram mais elevados nas gestantes (P<0,05), que correspondem ao periodo entre 90 e 180min. O teste de correlacao de Pearson revelou correlacao negativa entre concentracao de calcio e insulina nas gestantes (P<0,05). Estes resultados indicam menor taxa de metabolizacao de glicose em ovelhas gestantes e uma possivel relacao de calcio e insulina no terco final de gestacao.

Serum Metabolic Markers Pre and Postpartum in Holstein Cows According to the Mastitis Occurrence

Federal Catarinense Institute, Araquari Campus, Araquari, SC, Brazil. Federal University of Pelotas/NUPEEC, Center for Research, Education and Extension in Livestock, Pelotas, RS, Brazil. 4 Brothers Farm S.A., Rio Grande, RS. CORRESPONDENCE: V. Peripolli [vanessa.peripolli@hotmail. com Fax: +55 (47) 3803-7201]. Federal Catarinense Institute, Araquari Campus. CEP 89245-000 Araquari, SC, Brazil. Serum Metabolic Markers Pre and Postpartum in Holstein Cows According to the Mastitis Occurrence

Relationship between pre-partum body condition score changes, acute phase proteins and energy metabolism markers during the peripartum period in dairy cows

Abstract This study evaluated the relationship of pre-partum BCS variations on the acute phase response around parturition and milk production of dairy cows. The animals were divided into two groups: cows that gained BCS from the third to the first week pre-partum (GBC = n 11) and those that lost BCS (LBC = n 9) in the same period. Blood samples were collected pre and post-partum to determine serum concentrations of glucose (GLU), non-esterified fatty acids (NEFA), insulin (INS), albumin (ALB), paraoxonase (PON), haptoglobin (HP) and blood cell counts. The GBC group showed higher PON concentration in the postpartum (p < .05) and higher ALB concentration both pre and postpartum periods (p < .05), whereas the LBC animals showed a higher HP concentration in both periods (p < .05). Milk yield increased 3 kg/cow/day in the group that increased their BCS (p < .03). The LBC cows showed increased monocyte counts (p < .03), in addition to having a greater number of animals with the neutrophil:lymphocyte ratio higher than 1 (p < .03). The remaining parameters did not differ between groups. In conclusion, animals that lost BCS during the pre-partum period demonstrated to have a higher inflammatory status around parturition and lower milk production.

Prepartum administration of recombinant bovine somatotropin (rBST) on adaptation to subclinical ketosis of the ewes and performance of the lambs

The aim of this study was to determine the effect of prepartum rbST injection on the metabolic profile of pregnant ewes induced to subclinical ketosis, as well as the metabolism until seven days of life and weight gain until seven weeks of life of the lambs. Twenty seven pregnant ewes of the pantaneiro genetic group were used, divided into two groups: rbST group (n = 14) and control group (n = 13). The rbST group received two applications of 1 mg/kg of rbST, at 97 and 111 days gestation, while the control group received placebo injections. There were significant differences between groups in levels of GGT in the ketosis post induction period and BHB concentrations in the postpartum period. Concentrations of glucose, urea, phosphorus, albumin, cholesterol, AST, NEFA and insulin were not different between dams from the two groups in different periods of the study (P>0.05). There was an effect of rbST on body weight observed already at fourteen days of life (P<0.0001), there was an increase in serum phosphorus levels at birth of lambs (P=0.0014), and albumin at seven days of life (P = 0.0014) of the lambs, with no difference between groups for the other metabolites. Therefore, the use of rbST was effective in increasing the weight of the lambs until the seventh week of life. In addition, rbST treatment had positive effects on the dam metabolism with reduction of liver overload, as indicated by decreased GGT after ketosis induction and decreased BHB at the postpartum period.

EFEITO DE DIFERENTES COMBINAÇÕES HORMONAIS SOBRE A TAXA DE RETORNO AO ESTRO E PRENHEZ EM VACAS DE CORTE LACTANDO, SUBMETIDAS À INSEMINAÇÃO ARTIFICIAL EM TEMPO FIXO

O objetivo deste estudo foi avaliar o efeito do Hormonio Liberador de Gonadotrofinas (GnRH) e da Gonadotrofina Corionica Equina (eCG), bem como a associacao entre estes nas taxas de retorno ao estro e prenhez, em vacas de corte lactando, submetidas a inseminacao artificial em tempo - fixo (IATF). Foram utilizadas 223 vacas cruzadas, das quais 65,9% apresentavam condicao corporal (CC) ® ). As taxas de retorno ao estro e prenhez foram de 8,7 e 5% respectivamente, e nao diferiram entre os tratamentos (P>0,05). Conclui-se que nao houve efeito dos tratamentos na taxa de retorno ao estro e prenhez em vacas de corte lactando inseminadas em tempo - fixo.