Intrafollicular paraoxonase 1 activity and the steroidogenic potential of the first post-partum dominant follicle in dairy cows

Cows experiencing high levels of inflammation and specific metabolic conditions tend to have slower follicular growth and lower serum and follicular concentrations of oestradiol (E2). Paraoxonase1 (PON1) activity decreases during inflammatory processes. Therefore, the aim of this study was to evaluate the association between serum and intrafollicular (FF) PON1 activity and the serum and intrafollicular levels of E2 and progesterone (P4), as well as the mRNA expression of genes related to steroidogenesis, metabolism and inflammation in the first post-partum dominant follicle of Holstein cows. No correlation was found between PON1 activity, the expression of the analysed genes and levels of follicular E2 and P4, except for a negative correlation between serum E2 and follicular PO1 activity. Also, no correlation was found between serum and follicular PON1 during the first post-partum follicular wave.

Polymorphisms in the anti-oxidant paraoxonase-1 (PON1) gene associated with fertility of postpartum dairy cows

Paraoxonase 1 (PON1) is a negative acute phase plasma protein synthesized by the liver that has anti-oxidant activity. The aim of this study was to evaluate the association of single nucleotide polymorphisms (SNPs) in the PON1 promoter region with plasma PON1 activity and fertility in Holstein dairy cows. Sixty-eighty Holstein cows were used in this initial investigative study. Blood samples were collected weekly beginning 28 days prior to expected calving, twice weekly in week 1 and 2 postpartum, and then once weekly through 6 weeks postpartum for plasma PON1 activity analysis. Cows were synchronized for ovulation and timed AI at 63-70 DIM using an Ovsynch program. Pregnancy diagnosis was confirmed by rectal palpation and reproductive performance data was recorded until 210 DIM. DNA was extracted from blood of each cow and a fragment of proximal PON1 gene promoter was sequenced. Seven single nucleotide polymorphisms (SNPs) were identified in the promoter region of the PON1 gene at positions -22, -105, -176, -221, -392, -611 and -676, six of which were significantly associated with plasma PON1 activity level. The SNPs -221 and -392 were significantly associated with both plasma PON1 activity and the calving to conception interval (P < 0.05) with no significant effect on calving to first ovulation interval. In conclusion, the genotypes associated with higher plasma PON1 activity in SNP locations -221 and -392 were also associated with a reduced calving to conception interval in this study set of cows. These SNPs may provide novel genetic markers for improved fertility in future larger studies in dairy cows.

AÇÃO ANTI-HELMÍNTICA DO EXTRATO HIDROALCOÓLICO DE Alternanthera sessilis e Alternathera brasiliana EM OVINOS

Avaliou-se a atividade anti-helmíntica do extrato hidroalcoólico de plantas de Alternanthera sessilis e Alternanthera brasiliana em ovinos naturalmente infectados. Para o experimento foram utilizados 30 ovinos e estes foram distribuídos em 3 grupos:  grupo 1: controle, que recebeu 10 mL de água, grupo 2: com 10 mL de solução com concentração de 500 mg/L de extrato de A. brasiliana e grupo 3: com 10 mL de solução com concentração de 500 mg/L de A. sessilis. Os animais receberam o tratamento por via oral durante os dias 1, 2, 3, 4 e 5 e as coletas de fezes para avaliar a carga parasitária foram realizadas nos dias 2, 3, 4, 5, e 7. Os resultados demonstraram que não houve diferença significativa na redução de ovos por grama de fezes, bem como na porcentagem de redução de OPG. Conclui-se que nas condições deste trabalho, os extratos não apresentaram ação anti-helmíntica em ovinos.

The acute effect of intravenous lipopolysaccharide injection on serum and intrafollicular HDL components and gene expression in granulosa cells of the bovine dominant follicle

The aim of this study was to evaluate the effect of an acute systemic inflammatory response induced by lipopolysaccharide (LPS) in the serum and follicular fluid (FF) high-density lipoprotein (HDL) components, hormone concentrations and granulosa cell gene expression. For this purpose, twenty non-lactating Jersey dairy cows were submitted to a progesterone (P4) - estradiol (E2) based synchronization protocol. Cows received a single i.v. dose of LPS (2.5 μg/kg of body weight) or saline solution (CTL Group) 2 h after P4 insert removal. Blood, granulosa cells and FF samples were collected six hours after LPS injection. Five hours after LPS injection rectal temperature was increased in LPS (P < 0.0001, 40.4 ± 0.1 °C) compared to the CTL cows (38.8 ± 0.1 °C). Serum PON1 activity was reduced by LPS injection (130.2 ± 5.1 vs. 99.6 ± 3.3 U/mL; P < 0.001), as well as HDL-cholesterol concentrations (70.3 ± 5.3 vs. 50.1 ± 6.2 mg/dL; P < 0.05). The FF E2 and P4 concentrations were not different between groups (P > 0.05). The PON1 activity in the FF was also decreased by LPS injection (P = 0.01). In comparison to CTL group, cows injected with LPS had a ten fold reduction in STAR, TLR4 and TNF mRNA expression (P < 0.05). In conclusion, an intravenous LPS challenge in cows induced an acute systemic inflammatory response reducing HDL and its components in serum but not in the FF. Only PON1 activity serum reduction was reflected in the FF in the short term. Additionally, steroidogenic and inflammatory genes had reduced expression in the granulosa cells.

Effect of prepartum somatotropin injection in late pregnant Holstein heifers with high body condition score on metabolic parameters, resumption of ovulation and milk production

Acosta, D. A. V., Pfeifer, L. F. M., Schmitt, E., Schneider, A., Silveira, P. A. S., Jacometo, C. B., Brauner, C. C., Rabassa, V. R., Corrêa, M. N. and Del Pino, F. A. B. 2013. Effect of prepartum somatotropin injection in late pregnant Holstein heifers with high body condition score on metabolic parameters, resumption of ovulation and milk production. Can. J. Anim. Sci. 93: 287–292. In the early post-partum period of dairy cows the duration and intensity of negative energy balance, the level of body condition score (BCS) loss and the milk yield are strongly associated with the timing of the first ovulation. The aim of this study was to determine the effect of pre-partum injections of somatotropin in dairy heifers with high BCS on the metabolism, resumption of ovarian activity and milk production. Holstein heifers (n=20) with high BCS, were divided randomly into two groups: somatotropin (n=10), which received two doses of somatotropin (500 mg) at −28 and −14 d from calving and Control (n=10), which received placebo. Blood samples were collected for evaluation of β-hydroxybutyrate (BHBA) and non-esterified fatty acids (NEFA) concentrations. Follicular development was also monitored via ultrasound. Somatotropin had no effect on plasma NEFA (P=0.35 and P=0.46) or BHBA (P=0.20 and P=0.44,) concentrations in the pre-partum and post-partum period, respectively. Milk production was not different between control (17.53±0.66 kg cow−1 d−1) and somatotropin groups (16.13±0.67 kg cow−1 d−1) (P=0.14). Pre-partum somatotropin administration did not affect (P=0.28) the time of the first post-partum ovulation. The proportion of cows ovulating the first post-partum follicular wave was not different between groups (P=0.49). In conclusion, pre-partum somatotropin treatment in dairy heifers with high body condition score seems not to have any effect on markers of energy balance, milk production or development of the first follicular wave in the early post-partum period.