RESUMO
The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of frozen-thawed equine semen by the addition of l-carnitine (LC) to post-thawed semen. Different concentrations of LC were added to thawed samples to obtain four treatments control and 0.5, 1 and 2 mM LC. In the in vitro experiments, sperm motility and kinematics, membrane integrity and intracellular calcium ion concentration ([Ca2+ ]i ) were investigated, and the antioxidant bioactivity of LC was assessed by measuring hydrogen peroxide and nitrite concentrations (NO2 - ). The fertility rate was assessed via the artificial insemination of mares. The treatment with 1 mM LC increased sperm [Ca2+ ]i (60.6 ± 0.05 AU), reduced nitrite concentration (39.1 ± 14.9 µM/µg protein), increased the sperm straightness percentage (STR: 78.3 ± 5.3%) and increased the pregnancy rate (75%) as compared to the control ([Ca2+ ]i 48.4 ± 0.05 AU, NO2 - concentration 63.1 ± 14.4 µM/µg protein, STR 67.5 ± 7.9%, 12.5% pregnancy rate, p < 0.05). These results suggest that 1 mM LC acts as an antioxidant and stimulator of sperm metabolism in post-thawed equine semen, increasing the fertility rate. Thus, addition of LC might be an alternative to improve the fertility of poor quality post-thawed equine semen.
Assuntos
Preservação do Sêmen , Sêmen , Animais , Antioxidantes/farmacologia , Carnitina/farmacologia , Criopreservação/veterinária , Feminino , Fertilidade , Cavalos , Inseminação Artificial/veterinária , Masculino , Gravidez , Preservação do Sêmen/veterinária , Motilidade dos Espermatozoides , EspermatozoidesRESUMO
Young horses reach nearly 90% of their final height in the first year of life. However, to achieve their genetic potential, it is necessary to receive adequate nutrition during this period of rapid growth. The objective of this study was to evaluate the effect of supplementation of sorghum silage during a period of limited pasture forage availability, on the body development, and health of Mangalarga Marchador (MM) weanling fillies. Fourteen healthy MM 6-month-old fillies were randomly assigned to one of two groups: GS (consuming silage) and GH (consuming grass hay (Cynodon spp) in addition to 1.5% of body weight (BW) in dry matter (DM) of a fortified corn-based concentrate (17% CP [crude protein]), which was fed in individual stalls divided into two feedings/day for both groups. After concentrate feedings, the experimental groups remained loose in drylot pens of 50 m2, where the assigned forages were fed ad libitum with free access to salt and water. Group feed intake of the forages was recorded. It was assumed they were consuming a forage:concentrate ratio of 50:50. To assess development, the animals were weighed and measured for height at the withers and croup, body length, girth, and cannon bone circumference. The physical condition of animals, including BW, rectal temperature, mucous membrane color, and body condition score were assessed as well as serum biochemical analyses of creatinine, urea, total protein, gamma glutaminotransferase, aspartate aminotransferase, alkaline phosphatase, glucose, magnesium, calcium, and phosphorus concentrations were evaluated. The weights, morphometric measurements, clinical evaluation, and blood collections were done on the first day and every 21 days during the 84 days trial period. The growth performance and serum were subjected to analysis of variance for repeated measures, factoring treatment, and collection period. Despite higher (P < .05) DM and CP intakes by the GH fillies than those GS, there were no treatment effects (P > .05) on any of the development or health parameters measured. The use of sorghum silage as forage source for 84 days during the dry season had no negative impact on the body development and health of MM fillies (6-9 months of age) that were also fed 1.5% BW of a commercial concentrate balanced for growth.