Pastagens melhoradas e suplementação alimentar no comportamento reprodutivo de vacas de corte primíparas.

O desempenho reprodutivo de 122 vacas Devon primíparas foi avaliado nos seguintes tratamentos: T1: 33 vacas mantidas em campo natural (Axonopus sp; P. notatum Flugge); T2: 30 vacas em campo natural, suplementadas, em média, por 82 e 31 dias, respectivamente, no pré e pós-parto com 1 kg de feno (L. multiflorum L.; T. repens; T. subterraneum e campo natural) e 1,74 kg de farelo de arroz e 0,24 kg de farelo de soja vaca/dia; T3: 29 vacas mantidas em pastagem natural melhorada com as mesmas espécies forrageiras do feno do T2, por, em média, 73 dias e 40 dias no pré e pós-parto, respectivamente; T4: 30 vacas na mesma pastagem natural melhorada do T3 utilizada em média por 89 dias pré e 52 dias pós-parto. Durante o experimento manteve-se a lotação de uma vaca/ha para T1 e T2 e 1,5 vaca/ha para T3 e T4. Após os tratamentos, foi constituído um só grupo em campo natural com lotação de uma vaca com cria/ha. O campo natural não possibilitou ganhos diários de peso (GDM) satisfatórios (0,065 kg/dia; P<0,05) no final da gestação e início da lactação. A suplementação favoreceu os GDM das vacas (0,576 kg/dia). Vacas do T3 e T4 tiveram GDM maiores no pré (0,801 e 1,031) e pós-parto (0,506 e 0,520) e o melhor desempenho reprodutivo. Vacas com ganhos de peso na época de monta tenderam à melhor taxa de concepção. Não houve diferença entre tratamentos na taxa de prenhez, mas a comparação de T1 e T2 com o T3 e T4 indicou superioridade das pastagens melhoradas sobre o campo natural, com ou sem suplementação. Os índices de prenhez foram: T1= 81,3%; T2= 77,8%; T3 = 100,0%; e T4= 93,1%

CCR5D32 mutation in three Brazilian populations of predominantly Sub-Saharan African ancestry

This study reports the frequencies of the CCR5D32 mutation of the beta-chemokine 5 gene and discusses the possible effects of past and recent gene flow in three quilombo remnants (Brazilians communities with anthropological African ancestry whose ancestors were escaped slaves): Rio das Rãs, Mocambo, and São Gonçalo in the northeastern region of Brazil. The CCR5D32 allele frequency of the Mocambo population was significantly higher (5.6%) than that found in the Rio das Rãs (1%) and São Gonçalo (0.9%) populations. These differences may reflect different proportions of parental populations in the founders individuals, a founder-effect and/or different histories of inter-ethnic contact. The frequency of the CCR5D32 allele in the Mocambo sample is similar to that found in those urban Brazilian populations which have a large amount of European genetic input, indicating a European contribution to the gene pool of this population and suggesting that, perhaps since its foundation, Mocambo has had a high level of admixture or experienced a founder-effect

Analysis of the CCR5 gene coding region diversity in five South American populations reveals two new non-synonymous alleles in Amerindians and high CCR5*D32 frequency in Euro-Brazilians

The CC chemokine receptor 5 (CCR5) molecule is an important co-receptor for HIV. The effect of the CCR5*D32 allele in susceptibility to HIV infection and AIDS disease is well known. Other alleles than CCR5*D32 have not been analysed before, neither in Amerindians nor in the majority of the populations all over the world. We investigated the distribution of the CCR5 coding region alleles in South Brazil and noticed a high CCR5*D32 frequency in the Euro-Brazilian population of the Paraná State (9.3%), which is the highest thus far reported for Latin America. The D32 frequency is even higher among the Euro-Brazilian Mennonites (14.2%). This allele is uncommon in Afro-Brazilians (2.0%), rare in the Guarani Amerindians (0.4%) and absent in the Kaingang Amerindians and the Oriental-Brazilians. R223Q is common in the Oriental-Brazilians (7.7%) and R60S in the Afro-Brazilians (5.0%). A29S and L55Q present an impaired response to β-chemokines and occurred in Afro- and Euro-Brazilians with cumulative frequencies of 4.4% and 2.7%, respectively. Two new non-synonymous alleles were found in Amerindians: C323F (g.3729G > T) in Guarani (1.4%) and Y68C (g.2964A > G) in Kaingang (10.3%). The functional characteristics of these alleles should be defined and considered in epidemiological investigations about HIV-1 infection and AIDS incidence in Amerindian populations