Fabiana Moreira

Leptin and mitogen-activated protein kinase (MAPK) in oocytes of sows and gilts

Leptin is a modulator of oocyte maturation and follicular development in swine. The MAPK are serine/threonine kinases that act as signal transduction pathways in swine ovaries. This study evaluated the presence of leptin, activated MAPK ERK 1/2 and p38 in oocytes of primordial/primary, secondary and tertiary follicles of gilts and sows. Ovaries from ten gilts and ten sows were collected in an abattoir, fixed in 10% formalin and prepared with classical histology methods. For immunohistochemistry, slides were incubated with polyclonal antibodies anti-leptin, anti-phospho ERK1/2 MAPK and anti-phospho p38 MAPK. Leptin immuno-labeling and the presence of activated ERK 1/2 MAPK were more intense for oocytes of sows (P<0.05), whereas p38 MAPK was more active for oocytes of gilts (P<0.05). Although no differences in immunolabeling for leptin and p38 MAPK were observed for oocytes of gilts at distinct follicle developmental stages (P>0.05), immunolabeling was intense for oocytes of sows included in primordial/primary follicles (P<0.05). Thus, leptin and p38 MAPK may be important to start oocyte development.

Metabolic and reproductive parameters in prepubertal gilts after omega-3 supplementation in the diet

Polyunsaturated fatty acids may benefit reproductive performance of female swine. This study evaluated metabolic and reproductive parameters of prepubertal finishing gilts fed with fish oil as a natural source of omega-3 fatty acids (6.88g/d) (n=12) over a period of 45 d. Gilts in the control group were fed soybean oil (n=13). Body weight and backfat were determined at 15-d intervals. Serum levels of leptin, IGF-1, insulin, cholesterol and triglycerides were measured at the beginning (D0) and at the end of the period (D45). Immunolabeling intensity for leptin and its receptor (ObRb) was assessed in oocytes of preantral follicles. Gilts fed omega-3 presented slightly heavier uteri (P=0.09) than control gilts, but there was no effect on body weight and backfat (P>0.05). Cholesterol serum levels tended to be lower at D45 for omega-3 supplemented gilts than for controls (P=0.06). Triglycerides and IGF-1 serum levels were lower at D45 than at D0 for control gilts (P<0.05), but unaltered for supplemented gilts. Insulin levels were unaffected by supplementation (P>0.05), but were greater at D45 than at D0 in both treatments (P<0.05). Immunolabeling for leptin and ObRb in oocytes included in preantral follicles was more intense for supplemented gilts than for control gilts (P<0.05). Omega-3 supplementation was associated with reduced serum cholesterol level and more intense staining for leptin in oocytes of prepubertal gilts, which suggests some involvement on triggering puberty.

Boar sperm quality after supplementation of diets with omega‐3 polyunsaturated fatty acids extracted from microalgae

This study evaluated effects of diet supplementation with omega‐3 polyunsaturated fatty acids (PUFA) from microalgae on boar sperm quality. Two groups of boars (n = 3 each) were fed during 75 days either a commercial diet (control), or the same diet supplemented with omega‐3 PUFA from the heterotrophic microalgae Schizochytrium sp. (120 g/kg). Sixteen ejaculates were collected per boar. Some sperm kinetics parameters were inferior for supplemented than for control boars (p < .05): distance average path; distance in both curved and straight line; velocity average path, velocity in both curved and straight line; and amplitude of lateral head displacement. Spermatozoa from supplemented boars presented lower mitochondrial functionality, but greater membrane fluidity compared to the control group (p < .01). Membrane and acrosome integrity, production of reactive oxygen species and lipid peroxidation did not differ (p > .05). Serum cholesterol levels were greater (p < .05) for supplemented than for control boars at the 30th and 60th d of supplementation, but levels of triglycerides and IGF‐1 did not differ (p > .05). Compared to the control, spermatozoa of supplemented boars were slower, travelled shorter distances and presented impaired energy metabolism, but their greater membrane fluidity may potentially favour their cryopreservation.