The dynamism of microbial populations in the rumen has been studied with molecular methods that analyze single nucleotide polymorphisms of ribosomal RNA gene fragments (rDNA). Therefore DNA of good quality is needed for this kind of analysis. In this work we report the evaluation of four DNA extraction protocols (mechanical lysis or chemical lysis with CTAB, ethylxanthogenate or DNAzol(®)) from ruminal fluid. The suitability of two of these protocols (mechanical lysis and DNAzol(®)) was tested on single-strand conformation polymorphism (SSCP) of rDNA of rumen microbial populations. DNAzol(®) was a simple method that rendered good integrity, yield and purity. With this method, subtle changes in protozoan populations were detected in young bulls fed with slightly different formulations of a supplement of multinutritional blocks of molasses and urea. Sequences related to Eudiplodinium maggi and a non-cultured Entodiniomorphid similar to Entodinium caudatum, were related to major fluctuating populations in an SSCP assay.

Efecto del fenotipo (color de plumaje) sobre el peso del huevo y peso vivo de la gallina de traspatio Effect of phenotype (plumage colour) on egg weight and live weight of backyard hen

Gutierrez-Vazquez, E., Pena-Perez, F., Partida-Partida, M. and Flachowsky, G. 1994. Acceptance of fresh swine e m t a by growing Three groslp feeding experiments with 16, 12 and 16 zebu bulls of 235, 295 and 273 kg average initiul body weight wem carried out to investigate the i n f l u e m of fieding fryh swine excreta mired with molasses and corn stubbles on feed intake and weight gain during feeding periud of 105, 70 and 114 days, respectively. The diets contained 54, 35 and 27% fresh swine excreta; 25, 30 and 36% rnolasses;and21,35and37%cornstubblesinexperiments lA,Band 3A, respectively. In experiment IB a mixturn of swine waste and molusses and wrn stubbles were fed separately while in experiment 3B a mixturn of fresh swine waste 25%, molasses 44.5%, corn stubbles 30% and urea (0.5% on DM basis) was fed Voluntary intake of diet 1A became optimum after 3 weeks and in 1B after 9 weeks. Mean DM intakes were 2.71,2.12,2.63,2.81 and 2.55 k g / l O O

ABSTRACT. The objective was to determine the effect of diet on live weight (LW) and egg weight (EW) of backyard hens (BH) during the rainy season in the Bajío region of the state of Michoacán, Mexico. Seventeen municipalities were sampled, where 101 BH (six hens/municipality) were captured and weighed and 101 eggs (six eggs/municipality) were harvested and weighed. The crops of the captured hens were removed Post-sacrifice, the organic content/crop (OCC) was classified and weighed by components, to later perform chemical compositional analysis. Data were analysed using generalised linear models and the differences between municipalities were obtained by the method of least squares means. The weight of the OCC (36.4 ± 22.4 g) was affected by the municipality (P<0.001), but not by the LW of the BH (P>0.05). Commercial feed (8.1 ± 6.0 g), grains: maize and sorghum (13.9 ± 13.5 g) kitchen waste (1.5 ± 2.9 g), herbaceous (0.6 ± 0.9 g) and insects (0.3 ± 0.7 g) were found in the crop. According to the commercial feed (COF) component, two feeding systems (FS) were identified: traditional FS, without COF and nontraditional FS, with COF. The diets of both FS were similar (P>0.05) in nutritional composition and do not meet the nutritional requirements of the hens. The LW (1.567 ± 0.316 kg) and EW (51.3 ± 1.0 g) of the BH cannot be completely attributed to the diet consumed during the rainy season.Key words: backyard fowl, rural poultry, rural poultry feed. RESUMEN.El objetivo del estudio fue determinar el efecto de la dieta sobre el peso vivo (PV) y peso del huevo (Phvo) de las gallinas de traspatio (GT) durante la época de lluvias en la región Bajío del estado de Michoacán, México. Se muestrearon 17 municipios, en donde se capturaron y se pesaron 101 GT (seis/municipio) y se recolectaron y pesaron 101 huevos (seis/municipio). Se extrajeron, postsacrificio, los buches de las gallinas capturadas, cuyo contenido orgánico/buche (COB) fue clasificado y pesado por componentes, para posteriormente realizar el análisis bromatológico. La información se analizó mediante modelos lineales generalizados y las diferencias entre municipios se obtuvieron por la metodología de medias de mínimos cuadrados. El peso del COB (36,4 ± 22,4 g) fue afectado por el municipio (P<0,001), mas no por el PV de GT (P>0,05). En COB se encontró: alimento comercial (8,1 ± 6,0 g), granos: maíz y sorgo (13,9 ± 13,5 g), desperdicios de cocina (1,5 ± 2,9 g), herbáceas (0,6 ± 0,9 g) e insectos (0,3 ± 0,7 g). De acuerdo con el componente alimento comercial (AC) se identificaron dos sistemas de alimentación (SA): SA tradicional, sin AC y SA no tradicional, con AC. Las dietas de ambos SA fueron similares (P>0,05) en composición nutrimental y no cumplen con los requerimientos nutricionales de estas aves. El PV (1,567 ± 0,316 kg) y el Phvo (51,3 ± 1,0 g) de las GT no pueden ser completamente atribuidos a la dieta consumida durante la época de lluvias.Palabras clave: alimentación avícola rural, ave de corral, avicultura rural.

Objective. Determine the best non-linear model to fit the growth curve of local turkeys managed under confinement in Michoacan, Mexico. Material and methods. Twenty-four and 43 female and male turkeys, reared under commercial conditions were given commercial feed. Birds were weighed weekly from hatch to 29 weeks of age. The Gompertz, Brody, Richards, von Bertalanffy and Logistic models were chosen to describe the age-weight relationship. Results. The best fitting model was selected based on the multiple determination coefficient (R2), the Akaike information criterion (AIC) and visual analysis of the observed and predicted curves. In both female and male, von Bertalanffy was the best model. The highest estimates of parameter A (mature weight) for both females and males were obtained with the von Bertalanffy model followed by the Gompertz and Logistic. The estimates of A were higher for males than for females. The highest estimates of parameter k (rate of maturity) for both females and males were, in decreasing order, for the Logistic, Gompertz, and von Bertalanffy models. k values for female turkeys was higher than for males. The age at the point of inflection (TI) and body weight at the age of point of inflection (WI) varied with the model used. The largest values of TI and WI corresponded to the Logistic model. Between sexes, the largest TI and WI values corresponded to males. Conclusions. The best models to describe turkey growth was the von Bertalanffy because it present the highest R2 and lowest AIC values.