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RESUMO -Avaliou-se o efeito da suplementação de vitamina A na dieta sobre as características seminais (volume, motilidade, pH, vigor Assessment of vitamin A supplementation on boar semen characteristicsABSTRACT -The objective of this study was to evaluate the effect of vitamin A feed supplementation on the following boar semen characteristics: volume, motility, vigor, seminal pH, spermatic concentration, total number of spermatozoa, percentage of living sperm cells and morphologic abnormalities. The experiment was carried out with 10 hybrid boars (328.5 ± 2.12 days of age and 191.0 ± 12.0 kg live weight). The boars were separated into two treatments and fed with two vitamin A levels: control, 10.000 UI/kg feed daily; and vitamin A, 16.000 UI. The boars received 2.5 kg feed daily. A randomized complete design was used with replication measurements in time. There was no significant effect of vitamin A supplementation on the characteristics studied, and nor on the time and treatment interaction. The was significant effect of time on pH, spermatic concentration, total number of spermatozoa, percentage of living sperm cells, morphologic abnormalities, motility and vigor. Although detect significant differences were not detected between both treatments, numerical differences were detected indicating that vitamin A influenced the average increase in motility and the percentage of living sperm cells and the reduction in the percentage of morphologic abnormalities. Data showed support the idea that vitamin A is intimately associated with spermatogenesis.Key Words: boar, nutrition, semen, vitamin A IntroduçãoA suinocultura tem exigido averiguações mais aprofundadas da interação entre nutrição e reprodução. E o conhecimento dessa interação pode trazer benefícios na redução da idade à puberdade, melhoria da libido e do vigor sexual, e no desenvolvimento e manutenção das glândulas endócrinas (Close & Cole, 2001).Especificamente na espermatogênese, essa interação ganha relevância por se tratar de um processo que envolve a diferenciação das células germinativas e a expressão programada de diversos tipos e estágios de desenvolvimento celular. Entretanto, as mudanças morfológicas das células têm sido bem descritas, porém pouco se conhece sobre os mecanismos moleculares de regulação do gene envolvido neste evento reprodutivo (Lee et al., 2004).

AGRADECIMENTOSAos meus pais Jamil (in-memorian) e Onofria, minha eterna gratidão.À minha irmã Adibi e sobrinha Carolinne pela confiança e credibilidade.Ao professor Anibal, meu orientado, amigo e companheiro pela dedicação de verdadeiro Mestre.Aos professores Felix (in-memorian), Rubens, Paulo Mazza, Maria de Fátima, Ed Hoffman, Silvio Arruda, minha gratidãp.Francine, Simone, Sidney e Fabinho, obrigado pela dedicação ímpar para que esta pesquisa se tornasse realidade.À fazenda Paineiras, Dr. Tito Lívio, Rui, Natálio, Betinho e Kleber pela enorme colaboração.Aos colegas Edson de Almeida, Felipe, Carolina, José Ricardo, Raquel, Daniel (Emú), Laura, Marcão (falta acertar a coxinha e a passagem do "Buzão"), pelo apoio e amizade demonstrada.A DSM e ao Maurício Prata pelo apóio.Ao professor Desidério pelo incentivo, colaboração e participação na minha formação profissional.À minha esposa e companheira Ana Maria, aos meus filhos Pedro, Caio e Mariana pela paciência e apoio.À Deus pela minha vida. boars were utilized. The boars for the experiment came from a breeding swine operation located at the southeast of the SP state and were born from a hybrid synthetic genetic line. They were 70 days old and weighted an average of 25.16 Kg.At 117 days of age the inspection of the legs, testicles, prepuce's bag and penis was done. 12 animals among the 24 were selected and, at 193 days of age and weighting an average of 147 kg, they were transferred to the boars' unit of the referred Laboratory. The conditioning process started at 210 days of age and 8 weeks after all the boars were already mounting on the dummy, which completed the phase of the collections' stabilization. From this period, the values of the characteristics (volume and concentration) become stable, showing the homogeneity of the animals, which were used in the next experimental phase, related to the evaluation of the vitamin A effects on both treatments (Control and Vitamin A supplementation). In this second experimental phase we found significant differences (p< 0.05) considering motility, semen concentration determined by the Neubauer chamber and changes in the morphology of the spermatozoids, while no significant differences were found considering semen's concentration and volume. There was significance (p<0.05)considering time in the 25 collections, weekly collections, concentrations, Neubauer chambers and the total, while the interaction time x movement was not significant.The study lead us to conclude that due to the differential condition of the animals which were born from the present hybrid genetics, it is necessary to study the relationship nutrition x reproduction, once the positive effects of the vitamin A supplementation in the semen production was emphasized, mostly in the characteristics that are related to the formation of the sperm cells.Key words: Boar. Conditioning. Nutrition. Sêmen. Vitamine A. Acredita-se que as secreções epididimárias possuam fatores de maturação que conduzam à alterações como: no potencial para motilidade progressiva; no mec...