-The objective of this work was to investigate adjustments of the Gompertz, Logistic, von Bertalanffy, and Richards growth models, in male and female chickens of the Cobb 500, Ross 308, and Hubbard Flex lines. Initially, 1,800 chickens were randomly housed in 36 pens, with six replicates per lineage and sex, fed ad libitum with feed according to gender, and bred until 56 days of age. Average weekly body weight for each line and sex was used to estimate model parameters using the ordinary least squares, weighted by the inverse variance of the body weight and weighted with a first-order autocorrelated error structure. Weighted models and weighted autocorrelated error models showed different parameter values when compared with the unweighted models, modifying the inflection point of the curve and according to the adjusted coefficient of determination, and the standard deviation of the residue and Akaike information criteria exhibited optimal adjustments. Among the models studied, the Richards and the Gompertz models had the best adjustments in all situations, with more realistic parameter estimates. However, the weighted Richards model, with or without ponderation with the autoregressive first order model AR (1), exhibited the best adjustments in females and males, respectively.Index terms: autocorrelated errors, autoregressive model, poultry science, homogeneity of variance, mathematical model, weighting structures. Ajuste de modelos de crescimento em frangos de corteResumo -O objetivo deste trabalho foi investigar os ajustes dos modelos de crescimento Gompertz, Logístico, von Bertalanffy e Richards em frangos fêmeas e machos das linhagens Cobb 500, Ross 308 e Hubbard Flex. Foram inicialmente utilizados 1.800 frangos, alojados aleatoriamente em 36 unidades experimentais, com seis repetições por linhagem e sexo, alimentados à vontade com ração, de acordo com o gênero, e criados até 56 dias de idade. A partir do peso vivo médio semanal de cada linhagem e sexo, realizou-se a estimação dos parâmetros dos modelos, por meio dos mínimos quadrados ordinários, ponderados pelo inverso da variância do peso e ponderados com estrutura de erros autocorrelacionados de primeira ordem. Modelos ponderados e modelos ponderados com autocorrelação apresentaram valores diferentes dos parâmetros comparados aos modelos não ponderados, mudando o ponto de inflexão da curva e de acordo com o coeficiente de determinação ajustado, e o desvio padrão do resíduo e os critérios de informação de Akaike apresentaram os melhores ajustes. Entre os modelos estudados, os de Richards e Gompertz resultaram nos melhores ajustes em todas as situações, com as estimativas mais reais dos parâmetros. Porém, o modelo ponderado de Richards, com ou sem ponderação com o modelo autorregressivo de primeira ordem AR (1), apresentou os melhores ajustes em fêmeas e machos, respectivamente.Termos para indexação: erros autocorrelacionados, modelo autorregressivo, avicultura, homogeneidade da variância, modelos matemáticos, estruturas de ponderação.
ABSTRACT. Current assay evaluates the internal quality of eggs of Hy-Line W-36 hens, according to storage time, temperature and packaging. Two equal experiments, starting one day apart, were conducted with 140 eggs each. The two experiments were divided into two phases, from 1 to 9 days and from 9 to 21 days, in a randomized block design. In the 1 st phase, the treatments were arranged in a factorial 2 x 3+1, packaging (with or without), time (3, 6 and 9 days), with control on the 1 st day. In the 2 nd phase, treatments were arranged in a factorial design 2 x 2 + 1, packaging (with or without), cooling (with or without), and control on the 9 th day. Egg weight, albumen, yolk and shell percentage, yolk index and Haugh unit were evaluated. The internal quality was reduced (p < 0.05) during storage and the internal quality of eggs kept at room temperature decreased (p < 0.05), whereas eggs stored under refrigeration showed the same quality (p > 0.05) on the 9 th and 21 st days.Packaging assured better quality (p < 0.05), but not similar to the quality of refrigerated eggs. Results showed that the internal quality of the eggs was worse when there was no refrigeration during storage time and that packages provided better internal quality, although not as effective as cooling.Keywords: storage of eggs, type of packaging, Haugh unit.Qualidade interna de ovos de poedeiras comerciais em função do tempo, temperatura e embalagem de armazenamento RESUMO. Objetivou-se avaliar a qualidade interna de ovos de poedeiras comerciais da linhagem Hy-Line W-36 ® , em função da temperatura, tempo e embalagem. Foram conduzidos dois experimentos, que iniciaram com um dia de diferença, cada um com 140 ovos. Cada experimento foi dividido em duas fases, sendo de um a nove dias e de nove a 21 dias. O delineamento foi em blocos casualisados. Na primeira fase, os tratamentos foram arranjados em fatorial 2 x 3 + 1, embalagem (com ou sem), tempo (3, 6 e 9 dias), e um controle no primeiro dia. Na segunda fase, o arranjo foi 2 x 2+1, embalagem (com ou sem), refrigeração (com ou sem), e um controle no nono dia. Avaliou-se o peso do ovo, percentagem de albúmen, gema e casca, índice gema e unidade Haugh. A qualidade interna reduziu (p < 0,05) durante o armazenamento, e os ovos mantidos no ambiente apresentaram redução (p < 0,05) na qualidade interna, enquanto que os ovos sob a refrigeração apresentaram a mesma (p > 0,05) qualidade no nono e no 21º dia. A embalagem melhorou (p < 0,05) a qualidade, no entanto, não com a mesma eficiência que a refrigeração. Conclui-se que a qualidade dos ovos piora com o armazenamento se não houver refrigeração e a utilização de embalagem gera melhor qualidade interna, no entanto, não é tão eficaz quanto à refrigeração.Palavras-chave: armazenamento de ovos, tipo de embalagem, unidade Haugh.
This study aimed to determine whether broiler chickens display a preference for Tenebrio molitor larvae (TM) meal by evaluating ingredient acceptability and birds’ performance. Sixty 14-day-old male chickens were assigned into two treatment groups (5 birds/pen, n = 6) in a cafeteria-type study: the control (C) group, and the TM group. Each pen was equipped with one bell drinker and four through feeders allocated side by side; all feeders of the C group contained a complete standard diet whereas each feeder of the TM group contained one of the following ingredients: ground corn, extruded semi-whole soybean, vitamin-mineral supplement mixture, and TM meal. Feed intake was recorded daily and growth was monitored periodically up to day 32. Chickens which had access to individual feed components showed a delay to display preference for TM, but consumed, overall, up to 50% of the total intake as TM meal. Feed intake and growth performance were lower in all periods for TM group (p < 0.02), whereas feed conversion ratio was improved on days 22–28 and days 29–32 of age (p < 0.01). Data from bivariate and multidimensional analysis indicate that birds started to reach a balance of ingredient intake at 25 days of age, showing a high correlation between consumption of each ingredient and the day of the experiment. Chickens exhibited a preference for T. molitor meal, resulting in improved feed efficiency, which allows us to conclude that it can be a suitable feed alternative for poultry.
The objective of this study was to evaluate the effects of supranutritional level of selected B vitamins in different types of diet on broiler performance. Two experiments were conducted using male and female one-day-old chicks (n=288 each; initial body weights in experiment I and II was, respectively, 47.57 ± 0.43, and 47.98 ± 0.31) reared in batteries up to 18 days. In experiment I, the chicks were fed a corn and soybean meal-based diet and, in experiment II, a diet containing oxidized animal by-product meals and soybean oil was used. Both experiments followed a completely randomized design in a 3 × 2 factorial arrangement, consisting of the factors: i) supplementation levels of selected B vitamins (control, 3-or 6-times control of the vitamins riboflavin, pantothenic acid, niacin, folic acid and vitamin B 12 ); ii) dietary nutritional density (low or high), totaling 6 treatments and 8 replicates of 6 birds each (3 males and 3 females). As result of this study, in Exp. I, chicks showed higher weight gain (741.1 g vs. 697.3 g) and feed intake (920.2 vs. 878.5 g) when fed low-nutritional density diet with supra-nutritional vitamin level 6-times higher than the control. However, this effect was not found in the performance of chickens fed high-nutritional density diet. Despite the poor quality of the ingredients used in Exp. II, no statistical effect was shown of the use of vitamin super-dose in rations with different dietary nutrient density. Feed conversion ratio (FCR) was significantly improved for chickens fed high-nutritional density diet (1.191 vs. 1.246 in experiment I, 1.244 vs. 1.275 in experiment II, p<0.01). We conclude that birds fed a vegetable diet formulated with low-dietary density improved body weight (BW) and feed intake (FI) when receiving supra-nutritional levels of vitamins 6-times higher than the control.
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