RESUMO: Objetivou-se, neste estudo, comparar modelos não lineares ajustados às curvas de crescimento de codornas para determinar qual modelo que melhor descreve o crescimento de codornas e verificar a similaridade dos modelos analisando as estimativas dos parâmetros. Para as análises foram utilizados os dados peso e idade de codornas européias de corte (Coturnix coturnix coturnix) proveniente de três linhagens, em um esquema fatorial 2x4, instalado em um delineamento inteiramente casualizado, com dois níveis de energia metabolizável e quatro níveis de proteína bruta, com seis repetições. Os modelos não lineares utilizados foram: Brody, Von Bertalanffy, Richards, Logístico e Gompertz. Para a escolha do melhor modelo utilizou-se o Coeficiente de Determinação Ajustado, o Percentual de Convergência, o Quadrado Médio do Resíduo, o Teste de Durbin-Watson, o Critério de informação Akaike e o Critério de informação Bayesiano como avaliadores da qualidade do ajuste. Utilizou-se a análise de agrupamento para verificar, baseado nas estimativas médias dos parâmetros, a similaridades entre os modelos. Entre os modelos estudados, o Richard foi o mais adequado para descrever as curvas de crescimento. Os modelos Logístico e Richards foram considerados similares nas análises sem distinção de linhagem, bem como nas análises das Linhagem 1, 2 e 3.

ABSTRACT: The objective of this study was to compare non-linear models fitted to the growth curves of quail to determine which model best describes their growth and check the similarity between models by analyzing parameter estimates.Weight and age data of meat-type European quail (Coturnix coturnix coturnix) of three lines were used, from an experiment in a 2 × 4 factorial arrangement in a completely randomized design, consisting of two metabolizable energy levels, four crude protein levels and six replicates. The non-linear Brody, Von Bertalanffy, Richards, Logistic and Gompertz models were used. To choose the best model, the Adjusted Coefficient of Determination, Convergence Rate, Residual Mean Square, Durbin-Watson Test, Akaike Information Criterion and Bayesian Information Criterion were applied as goodness-of-fit indicators. Cluster analysis was performed to check the similarity between models based on the mean parameter estimates. Among the studied models, Richards’ was the most suitable to describe the growth curves. The Logistic and Richards models were considered similar in the analysis with no distinction of lines as well as in the analyses of Lines 1, 2 and 3.

ABSTRACT The objective of this study was to estimate the growth parameters of body weight and body nutrient deposition in males and females of one meat- (Coturnix coturnix coturnix) and two laying-type quail strains (Coturnix coturnix japonica), designated either yellow or red, using the Gompertz model. A total of 1350 quail from 1 to 42 days of age were used and they were distributed in a completely randomized design, with five replications for each strain. The parameters of body weight and body composition of the quail were analyzed weekly and evaluated using the Gompertz equation; growth rates and body nutrient deposition were evaluated through derivative equations. The three strains evaluated showed differences in their potential, growth rates, and body chemical composition. The composition up to 42 days of age was not sufficient to adjust the fat deposition data using Gompertz. Due to the period evaluated, the Gompertz model allowed to verify that females have higher body growth rates when compared with males of the same strains, with accelerated growth up to 14 and 21 days of age for males and females, respectively. Regarding the laying strain, the red has greater growth, with similar potential in depositing protein and water in the carcass, but they are more precocious in the deposition of these nutrients.

ABSTRACT The objective of this study was to determine the adjustment quality of non-linear models and estimate the growth parameters and body chemical composition of a meat-type quail strain (Coturnix coturnix coturnix) and two laying quail strains (Coturnix coturnix japonica), designated yellow and red. The study used 1500 quail, not sexed, distributed in a completely randomized design with three treatments and five repetitions. The experimental period was from 1-42 days of age. The birds were raised in a conventional system and fed ad libitum with a diet formulated to meet their nutritional requirements. Quail were weighed weekly, and a representative sample was slaughtered to evaluate their body chemical composition. The adjustment quality of the models was evaluated by means of the residual mean square (RMS), regression residue squares sum (SSRR), and number of iterations required for convergence. In evaluating the adjustment quality for the body weight of the three strains, the Gompertz, Logistic, and Von Bertalanffy models gave good fit, with Gompertz providing the best adjustment among them. For body composition, the Gompertz and Logistic models were the best, with Gompertz showing a slight superiority. Gompertz is the best model for describing growth curves and body chemical composition of body weight, protein, water, and ash in meat-type quail. In addition, it is the best model for describing growth curves and body chemical composition of body weight of yellow laying quail and of body weight, protein, and ash in red laying quail. Logistic was the best model for describing growth curves and body chemical composition of water, protein, and ash in yellow laying quail, and of water in red laying quail.

O objetivo deste trabalho foi avaliar a qualidade microbiológica e a vida útil de filés de tilápia-do-nilo, submetidos a diferentes métodos de defumação e condições de armazenamento. Foram utilizados dois processos de defumação (a frio ou a quente), em filés com ou sem pigmentação. Os produtos foram armazenados sob refrigeração ou congelados, e monitorados por 28 dias para avaliação da vida útil. Os filés congelados foram monitorados continuamente por 146 dias, apenas para a análise de ácido tiobarbitúrico (TBA). Defumação a quente e a frio reduziram a quantidade de coliformes, respectivamente em 99,78% e 97,80%. O armazenamento do produto sob refrigeração permitiu a redução de 99,73% dos coliformes, e o armazenamento sob congelamento os reduziu em 99,83%. Os valores encontrados de coliformes fecais estiveram dentro do limite permitido. Os valores de TBA nos filés atingiram o máximo no 14o dia de armazenamento. Os valores de TBA nos tratamentos sob refrigeração foram superiores aos daqueles sob congelamento e, também, em filés defumados a frio, em comparação aos defumados a quente. O processo de defumação a quente, com posterior armazenamento sob congelamento, é a técnica mais apropriada para assegurar qualidade e maior período de vida útil para os filés de tilápia-do-nilo, independentemente do processo de pigmentação.

The objective of this work was to evaluate the microbiological quality and shelf life of Nile tilapia fillets subjected to different smoking methods and storing conditions. Two smoking processes (cold or hot) were used in fillets with or without pigmentation. Products were stored under refrigeration or freezing, and monitored continually for 28 days for evaluation of their shelf life. Frozen fillets were monitored for 146 days for analysis of thiobarbituric acid (TBA) only. Hot- and cold-smoking reduced the coliform quantity, respectively, by 99.78% and 97.80%. Product storage under refrigeration allowed a 99.73% coliform reduction, and storage under freezing reduced them by 99.83%. Fecal coliform values were within the allowed limits. TBA values in fillets reached their maximum on the 14th storage day. TBA values were higher in treatments under refrigeration storage than in those under freezing, as well as in cold-smoked fillets in comparison to the hot-smoked ones. Hot-smoked process, followed by refrigeration storage, is the most adequate technique to ensure quality and a larger shelf life for Nile tilapia fillets, regardless of pigmentation process.

Objetivou-se caracterizar peles de tilápia-do-nilo, conservadas por congelamento e salga a seco, visando à extração de gelatina em processo batelada. Após a filetagem, as peles foram descarnadas e distribuídas em dois lotes. Um dos lotes foi congelado a -18 ºC por sete dias e o outro foi salgado e mantido a 25 ºC por sete dias. As peles foram lavadas, pesadas e pré-tratadas em solução de H2SO4 a10N (pH 3,0), na proporção de 1:6 (pele:água) por uma hora a 24 ºC. Extraiu-se a gelatina em banho-maria a 50 ºC por uma hora e retirou-se uma amostra para análise do perfil molecular. O restante foi congelado a -18 ºC. Foram realizadas análises físico-químicas das peles e das gelatinas líquidas, do perfil molecular com as gelatinas e análises microbiológicas das peles. As peles congeladas e salgadas apresentaram, respectivamente, 78,13 e 76,46% de umidade; 18,16 e 19,59% de proteína bruta; 2,26 e 1,90% de extrato etéreo e 1,44 e 2,06% de cinzas. Nas gelatinas líquidas extraídas das peles congeladas e salgadas, a umidade foi de 97,68 e 96,08%, o conteúdo de proteína bruta de 3,18 e 4,12%, de extrato etéreo 0,29 e 0,18% e de cinzas de 2,31 e 3,03%, respectivamente. Os valores da força de gel e viscosidade foram maiores para a gelatina de peles salgadas (200 g e 19,02mPas) em comparação à gelatina de peles conservadas pelo congelamento (12,7 g e 9,16mPas). O perfil molecular foi menor na gelatina extraída a partir de peles congeladas, portanto houve perda de β e γ-componentes, que indica grande degradação do colágeno decorrente do método de conservação.

The objective was to characterize Nile tilapia skins, freeze- and dry salt dry-preserved to extract gelatins by batch processing. After filleting, the skins were separated from the meat and distributed into two lots: In one, skins were frozen for 7 days (-18 ºC); and in the other, skins were salted for seven days (25 ºC). The skins were rinsed, weighed and pretreated in H2SO4 a10N solution (pH 3.0), at a 1:6 (skin/water) ratio for 1 h at 24 ºC. Gelatin was extracted in water bath at 50 ºC for 1 h, and a sample was removed for molecular profiling; the rest was frozen at -18 ºC. Physical-chemical analyses were carried out on the skins and liquid gelatins, the molecular profile was obtained from the gelatins, and the skins underwent microbiological analyses. Frozen and salted skins showed, respectively: 78.13% and 76.46% moisture, 18.16% and 19.59% crude protein, 2.26% and 1.90% ether extract, and 1.44% and 2.06% ash, respectively. For the liquid gelatins extracted from frozen and salted skins, moisture was 97.68% and 96.08%, crude protein was 3.18% and 4.12%, ether extract was 0.29% and 0.18%, and ash was 2.31% and 3.03%, respectively. Gel strength and viscosity values were higher for salted skins gelatin (200 g and 19.02 mPas) compared with freeze-preserved skins gelatin (12.7 g and 9.16 mPas). The molecular profile was lower in gelatin extracted from frozen skins, which indicates loss of β and γ-components, which indicates considerable collagen decay from that preservation method.