Luiza Rodrigues Alves Abreu

Crescimento de codornas de diferentes grupos genéticos por meio de modelos não lineares

ABSTRACTThis work aimed to adjust nonlinear models to describe the growth pattern of meat type and posture quail genotypes from hatch to 35 days of age. A total of 1280 male and female quails from EV1, EV2, UFV1, UFV2, UFV3, LF1 and LF2 and Posture genotypes were weighed every seven days, from hatch to 35 days of age. Brody, Gompertz, Logistic, von Bertalanffy and Richards models were used to fit the growth of the genetic groups. Statistical analyses were performed using PROC NLIN of SAS (Statistical Analysis System, version 9.0). The criteria used to select the model showing the best goodness of fit to the growth of the genotypes were: Adjusted Coefficient of Determination (R2), Asymptotic Standard Deviation (DPA), Absolut Mean Deviation (DMA), Asymptotic Index (AI), Bayesian Information Criterion (BIC), Akaike Information Criterion (AIC) and Errors Mean Square (MSE). All nonlinear models converged for the studied genotypes, except Richard the model for the Posture genotype. In general, the estimated parameters for the growth curve using nonlinear models suggested higher precocity for the Posture genotype in comparison to meat type genotypes. The Richard model overestimates the inflection point for all genotypes, except for the Posture genotype. The Gompertz, Logistic and von Bertalanffy are recommended to describe the growth patterns of the studied quail genetic groups. The Brody model did not converge and is not recommended to describe the genetic growth of the studied groups.

Influência do sexo e idade de abate sobre rendimento de carcaça e qualidade da carne de codornas de corte

The objective of this work was to evaluate the effect of sex and two ages at slaughter on the performance, carcass traits and meat quality of quails (Coturnix coturnix). Forty quails (males and females) were slaughtered at an age of 35 and 42 days. Then, the body weight, hot and cold carcass weight, breast weight, leg weight, hot and cold carcass yield, breast yield, leg yield, initial and final (24 hours post-mortem) pH values, water-holding capacity (WHC), color (L*, a* and b*), cooking loss and objective tenderness (shear force) were evalauted. There were no differences in carcass and cuts yields between the ages at slaughter. However, the quails slaughtered at 42 days of age had higher body weight than the quails slaughtered at 35 days of age. As to the parameters of meat quality, the initial pH values were lower in quails slaughtered at 42 days of age than in quails slaughtered at 35 days of age. Females slaughtered at 35 days of age had meat with lower degree of redness. The pH values of meat from males were lower with regard to those ones of meat from females. Therefore, the slaughter at 42 days of age yielded a better performance and carcass traits in males quails.

Características de desempenho e de carcaça em diferentes genótipos de codornas de corte

This study was carried out to compare and relate the performance and carcass traits of different quail genotypes from hatch to 35 days of age. A total of 1176 one-day-old quails of both sexes were allotted in a completely randomized experimental design, in a 7x2 factorial scheme (genotypes x sexes), in seven replicates with 12 quails per experimental unit. Quails of each genotype were weighed weekly from hatch to 35 days of age. At 35 days of age two males and two females of each genotype and replicate were sampled and slaughtered to evaluate carcass weight and main cut yield. Statistical analyses were performed by GLM and CORR procedure from the Statistical Analysis System (SAS, 2000, version 9.0), with the MANOVA option of the SAS device to assess the differences between the genotypes and the correlation between variables. There was no interaction (P≥0.05) between genotype and sex with the performance characteristics of weight and weight gain. However, there was a significant effect of genotype x sex (P<0.05) for the characteristics carcass,breast, thigh and drumstick weights. In general, quails of genetic groups UFV1, UFV2 and UFV3 were heavier from 7 to 35 days of age. We observed that for the correlation the tendency is that quail that showed higher body weight and weight gain will have greater housing and main cuts weight.

Modelos de norma de reação para estudo das características de qualidade da carne de codornas de corte em função das razões (metionina + cistina): lisina da dieta

ABSTRACTThis study aimed to evaluate the sensitivity of breeding values for meat quality traits of European quails fed different (methionine + cystine): lysine ratio diets from hatch to 21 days of age, using reaction norm models. A total of 9011 meat quality records from 1400 progenies of 80 sires and 160 dams from two lines (LF1 and LF2) were used in the analyses considering homogeneity of residual variance. The quails from hatch to 21 days of age were fed diets containing 0.61, 0.66, 0.71, 0.76 and 0.81 (methionine + cystine): lysine ratios, 26.12% of crude protein and 2900 ME/kcal of diet. From 22 to 35 days of age all quail were fed a diet containing 22% of crude protein and 3050 kcal ME/kg of diet. The random regression model analyses was performed using the WOMBAT program considering homogeneity of residual variance. Genetic variance and heritability estimates were affected by the environment gradient of diet and line, increasing these estimates with the increase of the (methionine + cystine): lysine ratio of the diet. The breeding values changed with the increase of the environment gradient of the diet with changes in the rank of genetic breeding values characterizing the existence of genotype by environment interaction for meat quality traits. Predictions of meat quality trait breeding values based on a given (methionine + cystine): lysine ratio are not valid for other levels of the amino acid ratio.

Genetic association between stayability, and productive and reproductive traits in Holstein cows

The objective was to estimate the genetic parameters for the cow’s ability to stay in the herd (stayability) until 48 and 54 months of age (STAY48 and STAY54) and up to 36 and 48 months after the first calving (STAY36ac and STAY48ac), and their associations with 305-day milk production (MP305) in the first lactation, age at first calving and first calving interval, from the first three lactations of cows reared in Brazil and born between 1987 and 2006. The covariance components were estimated by bivariate analyses, using the Bayesian approach. The a posteriori distributions of the components of interest were obtained with the Gibbs sampler. Fixed effect of contemporary group, additive and residual random genetic effect, and age of dam as covariate (linear and quadratic) were included in the analyses. Low heritability values were obtained for most traits, except for STAY48ac and MP305. Genetic correlation estimates between age at first calving and stayability traits were high and positive, except for STAY48ac. In addition, we detected genetic correlations between MP305 and STAY36ac and STAY48ac. In conclusion, we can infer that genetic correlations between MP305, and STAY36ac and STAY48ac indicate that the current focus on selection of animals for improved milk production in the first lactation can lead to genetic gains on longevity, although not expressive.

Carcass traits and meat quality of quails from both sexes and eight distinct strains

Our objective was to evaluate carcass traits and meat quality of quails from different strains and both sexes pertaining to three breeding-improvement programs. Quails from seven meat-type strains (UFV1, UFV2, UFV3, EV1, EV2, LF1 and LF2) and from one egg-laying (Japanese quail) strain (LAY) were slaughtered at 35 days of age. A completely randomised 8 (strain) × 2 (sex) factorial design was used for data analysis. Bodyweight, hot carcass weight and breast (musculus pectoralis major and m. pectoralis minor) and legs (thigh and drumstick) weights and their respective yields were determined. Ultimate pH, colour measurements, water-holding capacity, cooking loss and shear force were assessed. No difference in ultimate pH, shear force and hue was observed. The UFV3 strain had the greatest bodyweight at slaughter. The UFV3 strain had the greatest hot carcass weight in both sexes. The heaviest breasts were observed in both sexes of the UFV3 strain and in males of the UFV2 strain. The UFV3 quails had greater leg weight. The hot carcass yields of meat-type strains were greater than that of the LAY strain. The UFV3 and LAY females furnished a greater breast yield than did male quails. For males, the UFV1 strain had a greater yield of breast than that of LAY quails. The LAY quails presented the greatest yields of leg. The LAY quails had the least luminance, and the greatest water-holding capacity, cooking loss, red and yellow intensity, and chroma. In summary, meat obtained from meat-type strains had a greater water-holding capacity, lower cooking loss and greater luminance than that of the LAY strain. In addition, the meat-type strains grew appreciably faster, but the difference in yields of breast and leg meat between meat and layer strains was small. We conclude that meat-type strains, especially the UFV3, are more appropriate for enterprises focussed on meat production.

Lisina digestível em rações para frangos de corte tipo caipira

Two experiments were carried in order to determine digestible lysine requirements for free-range broiler hillbilly, Redbro lineage, males and females, created in free range system during the growing (43 to 56) and final phases (57 to 70 days). For this, 630 chickens were housed in 30 pens with pasture area and the experimental design was completely randomized in a factorial arrangement 5x2 (lysine and gender), with three replications with 21 chicks each. The digestible lysine levels evaluated were: 6.07, 7.07, 8.07, 9.07 and 10.07 (growth phase) and 6.00, 7.00, 8.00, 9.00 and 10.00 g/kg (final phase). Were evaluated the performance, the carcass and cuts yield, abdominal fat and meat quality characteristics. For the growth phase there were no differences of lysine levels on performance of the chiks, except for the consumption of digestible lysine. Therefore, the level of 6.07 g lysine /kg of diet meet the requirements of broilers of both genders. For the final phase it we observed effect of digestible lysine levels only to feed conversion, and the level of 8.51 g of lysine/kg of diet improve this trait.

Relações metionina + cistina: lisina digestíveis para codornas de corte machos em fase de terminação

In order of estimating the best relations methionine plus cystine: digestible lysine for quails males during the periods 22 to 28 and 29 to 35 days of age were developed two experiments. The quails received a basal diet deficient in methionine plus cystine, which were supplemented with five levels of DL-Methionine, replacing glutamic acid and starch, resulting in the following relations: 0.68, 0.73, 0.78, 0.83 and 0.88. A total of 280 quails distributed in a completely randomized design, with five treatments and eight replicates of seven quails per experimental unit. Feed intake, body weight gain, feed conversion, carcass yield and feathering of quails, composition of the carcass and nitrogen balance were evaluate. During the period from 22 to 28 days of age there was no effect for the variables studied front to relations methionine plus cystine : digestible lysine. During the period 29 to 35 days of age was observed effect on feed intake, methionine + cystine intake and weight gain. At 35 days old was observed effect on the yield of thigh and drumstick, ether extract and crude protein carcass and nitrogen retention. Are recommended that the relations methionine plus cystine : digestible lysine 0.68 and 0.88 over the period 22 to 28 and 29 to 35 days of age, respectively.

Lisina digestível na ração de frangos de corte tipo caipira na fase de crescimento

This experiment was conducted to determine the requirements of digestible lysine in male and female free-range broiler chickens (Redbro lineage) during the growth phase. Six hundred and thirty broiler chickens were allocated in 30 pens with access to the pasture area. The experimental design was completely randomized in a 5x2 (lysine and gender) factorial arrangement with 3 repetitions with 21 chickens each. The levels of digestible lysine evaluated were: 7.07, 8.07, 9.07, 10.07 and 11.07g/kg. The performance traits evaluated were lysine intake, feed intake, weight gain and feed conversion ratio. An interaction effect (P<0.05) was observed between dietary lysine level and gender for body weight gain. There was an effect (P<0.01) of the levels of lysine on lysine intake, body weight gain and feed conversion ratio. It was found that all the variables were affected (P<0.05) for the gender of chickens. We recommended 10.08 and 9.49 g of digestible lysine/kg diet, corresponding to the estimated intake of 21 and 20g of lysine, for males and females, respectively, for better body weight gain of chickens. For better feed conversion ratio, the recommendation is of 9.61 g of lysine/kg of diets, for chickens of both genders, corresponding to the estimated intake of 20g of lysine.

Desempenho de codornas de corte em cruzamentos dialélicos

The aim of this study was to evaluate the performance of four strains of meat type quails, designated L1, L2, L3 and L4 in diallel crosses. This study was carried out at the premises of the Genetic Improvement Program for Quails of UFVJM, from December 2011 to May 2012. The average body weight at hatch, at 35 and at 42 days old, the average daily feed intake at 35 and at 42 days old, and feed conversion at 35 and 42 days old were evaluated. Diallel analyzes were developed using univariate analyses, considering the methodology of complete diallel, from the average of the genotype combinations resulting in a complete randomized design with three replications. The combining ability analysis revealed significance for general combining ability for all traits, except for average feed intake and feed conversion at 35 days old. There was significant effect of specific combining ability for hatch weight (L2xL3; L2xL4; L1xL4); feed conversion from hatch to 35 days of age (L1xL3; L2xL4), and from hatch to 42 days (L1xL3; L2xL3; L2xL4); and average feed intake from hatch to 35 days of age (L1xL3; L2xL3), thus allowing the identification of more favorable hybrid combinations. The reciprocal effect showed significance only for hatch weight. Based on general combining ability, the strains which are more favorable for increased body weight were L1 and L2. For feed conversion, for the specific combining ability, the crosses L1xL3 and L2xL4 showed the best results, while for feed intake from hatch to 35 days old, the crosses L1xL3 and L2xL3 would be the most suitable.