Diluente Tris suplementado com óleo de Mauritia flexuoxa sobre a qualidade do sêmen caprino após a criopreservação / Tris diluent supplemented with Mauritia flexuoxa oil on the quality of goat semen after cryopreservation

Objetivou-se verificar os efeitos, nos parâmetros espermáticos, na integridade mitocondrial, acrossomal e de membrana em células espermáticas, desencadeados pelo uso do Tris (Tris hidroximetil aminometano) suplementado com óleo de Mauritia flexuoxa como diluente para criopreservação de sêmen caprino. Quatro caprinos clinicamente saudáveis foram utilizados. Os animais eram alimentados diariamente com volumoso (Pennisetum purpureum, Schum.), concentrado (ração peletizada com teor de 20% proteína, 300 g/animal/dia) e sal mineral específico para Caprinos (Caprinofós®), à vontade. Dois ensaios foram realizados: I – Teste de toxicidade; II – Criopreservação do sêmen com concentrações ideais. No teste de toxicidade as concentrações avaliadas foram: 5%, 10%, 15% e 20% de diluente a base de óleo de Mauritia flexuoxa. Após o teste de toxicidade, foi escolhido a concentração que apresentou o melhor resultado (5%). Logo após, foram realizadas mais 32 coletas, que foram diluídas em Tris-gema-glicerol (grupo controle) ou diluente contendo óleo vegetal (Mauritia flexuoxa). As amostras foram criopreservadas com auxílio do aparelho Tk3000®. Após o período mínimo de uma semana as palhetas foram descongeladas em banho-maria a 37 °C por 30 segundos, acondicionadas em microtubos de centrifugação e homogeneizadas para a análise imediata de motilidade, vigor espermático e morfologia. Em seguida, por meio de sondas fluorescentes foram avaliadas a integridade de acrossomo, membrana plasmática (Diacetato de Carboxifluresceína e Iodeto de Propídeo) e função mitocondrial sob microscopia de epifluorescência. Quanto a motilidade e vigor, integridade mitocondrial e acrossomal, o grupo buriti foi inferior ao grupo controle. O Tris suplementado com óleo de Mauritia flexuoxa na concentração de 5% não influenciou significativamente a qualidade espermática, porém, observouse morfologia e integridade de membrana favoráveis. Dessa forma, sendo uma alternativa para substituição de diluentes a base de produtos de origem animal.

The objective was to verify the effects, sperm parameters, mitochondrial, acrosomal and membrane integrity in sperm cells, triggered by the use of Tris (Tris hydroxymethyl aminomethane) supplemented with Mauritia flexuoxa oil as a diluent for cryopreservation of goat semen. Four goats clinically healthy were used. The animals were fed daily with bulky (Pennisetum purpureum, Schum.), concentrate (pelleted feed with 20% protein content, 300 g / animal / day) and mineral salt Specific for Goats (Caprinofós®), ad libitum. Two tests were carried out: I - Toxicity test; II - Semen cryopreservation with ideal concentrations. In the toxicity test as selected were: 5%, 10%, 15% and 20% of Mauritia flexuoxa oil-based diluent. After the toxicity test, the concentration that showed the best result (5%) was chosen. Soon after, a further 32 samples were obtained, which were diluted in Tris-glycerol (control group) or diluent containing vegetable oil (Mauritia flexuoxa). The samples were cryopreserved using the Tk3000® machine. After a minimum of one week, the samples were thawed in a 37 ° C water bath for 30 seconds, packed in centrifugation microtubes and homogenized for immediate analysis of motility, sperm vigor and morphology. Then, by means of fluorescent probes, the integrity of the acrosome, plasma membrane (Carboxyflurescein diacetate and Propidium Iodide) and mitochondrial function under epifluorescence microscopy were evaluated. As for motility and vigor, mitochondrial and acrosomal integrity, the buriti group was inferior to the control group. Tris supplemented with Mauritia flexuoxa oil at a concentration of 5% did not significantly influence sperm quality, however, favorable motility, morphology and membrane integrity were observed. Thus, being an alternative to replace diluents based on products of animal origin.

Residual feed intake: a nutritional tool for genetic improvement.

The goal of this bibliographical study was to provide information about residual feed intake (RFI), a new criterion used in the selection of beef cattle for growth rate, food ingestion, and feed efficiency. RFI is calculated as the difference between real consumption and the quantity of food an animal is expected to eat based on its mean live weight and rate of weight gain. In studies of RFI, many speculations are made among researchers about the reliability of this criterion. However, there is a high genetic correlation with characteristics related to post-weaning consumption and maturity, indicating that the biological processes that regulate consumption and efficiency in young animals are similar to the processes that regulate consumption and efficiency in animals of greater age. In contrast to feed conversion, selection based on RFI seems to select for lower rates of consumption and lower animal maintenance requirements without changing adult weight or weight gain. Therefore, we conclude that the data indicate that there are extraordinary benefits to be gained from changing the goals of selection from increased weight gain to improved nutritional efficiency. Given the importance of animal production for economic development in Brazil choosing the best selection goals for livestock improvement is essential. To include an index of feed efficiency in future goals would be desirable, and RFI may play a part in this if economic methods of implementation can be developed.