Avaliação de oito variedades de milho em cruzamentos dialéticos, com análise das médias dos híbridos, das suas gerações avançadas e das autofecundações

Eight corn varieties, with great genetic diversity among them, were studied in a diallel cross system in order to evaluate their breeding potential. The means of the varieties, their hybrids and advanced generations were analyzed using the Gardner & Eberhart (1966) model. With the genetic constants estimated it was possible to estimate the mean grain yield for several types of populations (double hybrids, triple hybrids, synthetic varieties, etc). The best varieties were: Tuxpeño La Posta, Eto Blanco, Centralmex and Pérola Piracicaba.Oito variedades de milho, com grande diversidade genética, foram analisadas quanto ao seu potencial para o melhoramento, analisando-se as médias dos híbridos obtidos com os cruzamentos dialélicos entre as variedades e as populações relacionadas. Foi utilizado o modelo proposto por Gardner & Eberhart (1966) para estimar as constantes genéticas a partir das quais foram estimadas as médias de rendimentos (peso de grãos) das populações de interesse. As variedades que mais se sobressaíram foram, em ordem decrescente de importância: Tuxpeño La Posta, Eto Blanco, Centralmex e Pérola Piracicaba

Estimation methods of non-additive effects for characteristics of weight and scrotal circumference in crossbred beef cattle

The objective of this study was to investigate, in a population of crossbred cattle, the obtainment of the non-additive genetic effects for the characteristics weight at 205 and 390 days and scrotal circumference, and to evaluate the consideration of these effects in the prediction of breeding values of sires using different estimation methodologies. In method 1, the data were pre-adjusted for the non-additive effects obtained by least squares means method in a model that considered the direct additive, maternal and non-additive fixed genetic effects, the direct and total maternal heterozygosities, and epistasis. In method 2, the non-additive effects were considered covariates in genetic model. Genetic values for adjusted and non-adjusted data were predicted considering additive direct and maternal effects, and for weight at 205 days, also the permanent environmental effect, as random effects in the model. The breeding values of the categories of sires considered for the weight characteristic at 205 days were organized in files, in order to verify alterations in the magnitude of the predictions and ranking of animals in the two methods of correction data for the non-additives effects. The non-additive effects were not similar in magnitude and direction in the two estimation methods used, nor for the characteristics evaluated. Pearson and Spearman correlations between breeding values were higher than 0.94, and the use of different methods does not imply changes in the selection of animals

Quality of the eggs of commercial layers fed with sugarcane dry yeast

Este trabalho objetivou avaliar o efeito da adição de levedura seca (Saccharomyces cerevisiae) à dieta de poedeiras na qualidade dos ovos. Foram utilizadas 120 poedeiras comerciais com 33 semanas de idade, distribuídas em um delineamento estatístico de blocos ao acaso, com cinco tratamentos (0, 7, 14, 21 e 28% de levedura), quatro repetições e seis aves por unidade experimental. Rações isoprotéicas (18% de proteína bruta), isoenergéticas (2.800 kcal de energia metabolizável/kg), isocálcicas (3,8% Ca) e isofosfóricas (0,38% P disponível) foram formuladas à base de milho e farelo de soja. Os níveis de levedura seca não alteraram o peso do ovo (64,35±0,85 g), a altura do albúmen (7,95±0,22 mm), a unidade Haugh (87,42±1,31), os sólidos totais da gema (50,86±0,20%), o extrato etéreo da gema (30,74±0,26%), a proteína da gema (16,92±0,16%), a gravidade específica do ovo (1,0912±0,001 g/mL), o peso da casca (6,67±0,08 g) e a espessura da casca (0,4671±0,003 mm). Foi observado efeito quadrático na variável cor da gema no terceiro ciclo de postura. A inclusão de até 28% de levedura seca nas rações intensificou a cor da gema e foi considerada uma prática viável pela análise econômica.This work aimed at evaluating the effect of the addition of dry yeast (Saccharomyces cerevisiae) to the laying diet on the quality of the eggs. One hundred and twenty chickens with 33 weeks of age were used in a randomized block design, with five treatments (0, 7, 14, 21 and 28% of dried yeast), four replicates and six birds per pen. Diets similar in protein (18% of crude protein), energy (2,800 kcal of metabolizable energy/kg), calcium (3.8%) and in phosphorus (0.38% of available phosphorus) were formulated based on corn and soybean meal. The levels of dry yeast did not affect egg weight (64.35±0.85 g), albumen height (7.95±0.22 mm), Haugh unit (87.42±1.31), total yolk solids (50.86±0.20%), ether extract of yolk (30.74±0.26%), yolk protein (16.92±0.16%), egg specific gravity (1.0912±0.001 g/mL), shell weight (6.67±0.08 g) and shell thickness (0.4671±0.003 mm). Quadratic effect was observed for the variable yolk color in the third laying cycle. The inclusion of dry yeast up to 28% provided increase on yolk color and proved to be economicaly viable

Successful xenogeneic germ cell transplantation from Jundia catfish (Rhamdia quelen) into adult Nile tilapia (Oreochromis niloticus) testes

Fish germ cell transplantation presents several important potential applications for aquaculture, including the preservation of germplasm from endangered fish species with high genetic and commercial values. Using this technique in studies developed in our laboratory with adult male Nile tilapias (Oreochromis niloticus), all the necessary procedures were successfully established, allowing the production of functional sperm and healthy progeny approximately 2 months after allogeneic transplantation. In the present study, we evaluated the viability of the adult Nile tilapia testis to generate sperm after xenogeneic transplant of germ cells from sexually mature Jundia catfish (Rhamdia quelen) that belong to a different taxonomic order. Therefore, in order to investigate at different time-periods post-transplantation, the presence and development of donor PKH26 labeled catfish germ cells were followed in the tilapia seminiferous tubules. From 7 to 20 days post-transplantation, only PKH26 labeled spermatogonia were observed, whereas spermatocytes at different stages of development were found at 70 days. Germ cell transplantation success and progression of spermatogenesis were indicated by the presence of labeled PKH26 spermatids and sperm on days 90 and 120 post-transplantation, respectively. Confirming the presence of the catfish genetic material in the tilapia testis, all recipient tilapias evaluated (n = 8) showed the genetic markers evaluated. Therefore, we demonstrated for the first time that the adult Nile tilapia testis offers the functional conditions for development of spermatogenesis with sperm production from a fish species belonging to a different order, which provides an important new venue for aquaculture advancement. © 2016 Elsevier Inc

Uso de redes neurais artificais na predi??o de valores gen?ticos para peso aos 205 dias em bovinos da ra?a Tabapu?.

Dados de 19240 animais Tabapu?, provenientes de 152 fazendas localizadas em diversos estados brasileiros, nascidos entre 1976 e 1995, foram utilizados para predi??o do valor gen?tico do peso aos 205 dias de idade (VG_P205) por meio de redes neurais artificiais (RNAs) e usando o algoritmo LM ? Levenberg Marquardt ? para treinamento dos dados de entrada. Por se tratar de rede com aprendizado supervisionado, foram utilizados, como sa?da desejada, os valores gen?ticos preditos pelo BLUP para a caracter?stica P205. Os valores gen?ticos do P205 obtidos pela RNA e os preditos pelo BLUP foram altamente correlacionados. A ordena??o dos valores gen?ticos do P205 oriundos das RNAs e os valores preditos pelo BLUP (VG_P205_RNA) sugeriram que houve varia??o na classifica??o dos animais, indicando riscos no uso de RNAs para avalia??o gen?tica dessa caracter?stica. Inser??es de novos animais necessitam de novo treinamento dos dados, sempre dependentes do BLUP.Data from 19,240 Tabapu? animals from 152 farms located in different states of Brazil, born from 1976 to 1995, were used to predict the genetic value of body weight at 205 days of age (BV_P205) of Tabapu? beef cattle using Artificial Neural Networks (ANN) and LM algorithm - Levenberg Marquardt training for data entry. Due to the use of networks with supervised learning, the predicted breeding values for P205 from BLUP were used as desired output. The breeding values for P205 obtained from RNA and those predicted by BLUP were highly correlated. The ranked breeding values for body weight at 205 days through RNA and those predicted by BLUP (VG_P205_RNA) showed a variation in the classification of animals indicating risks in the use of ANNs procedure for genetic evaluation of this trait. Insertions of new animals require new training data always dependent on BLUP