-An experiment was conducted to estimate the parameters of the Gompertz, Brody, Logistic, and Von Bertalanffy equations through Bayesian inference and evaluate the potential for growth in terms of weight and body composition of laying female quail (Coturnix coturnix japonica). The weights and body compositions of the birds were obtained weekly (1-119 days), allowing the adjustment of the four equations by Bayesian inference. The parameters mature weight (β1), integration constant (β2), maturity rate (β3), and their credibility intervals in four models on body weight and body components were properly estimated by Bayesian inference to describe the body growth in laying quail. The inflection point was determined by the 1st and 2nd derivatives of the Gompertz equation for body weight and body components (fat, protein, ash, and water). Based on Deviance Information Criterion (DIC) for the studied and analyzed variables, there is a model that fits best as a result of its better performance to achieve the DIC value. The Von Bertalanffy model proved to be very versatile, not obtaining good fit of data only for fat. The study shows that other models can also be used in several data sets as an alternative to Gompertz, which, due to its adequate biological interpretation and desirable characteristics in a curve growth, is generally the most used.

This study aimed to evaluate the effect of heat stress (HS) and selenium supplementation on markers of stress, meat quality and gene expression. For this, meat quails of 42 days of age were fed a diet that either met [0.33 mg/kg, nutritional demand for selenium (SS)] or did not meet [0.11 mg/kg, selenium deficient (SD)] the nutritional demands for selenium during the 7 days of evaluation. In addition, the animals were kept at either a thermal comfort temperature (25 °C) or exposed to HS (38 °C for 24 h). Glutathione synthetase (GSS), glutathione reductase (GSR) and uncoupling protein (UCP) gene expression were influenced by the interaction between temperature and diet. Animals subjected to HS and fed the SS diet exhibited the highest GSS and GSR gene expression. In terms of UCP gene expression, the lowest values were observed in HS animals on the SD diet. Glutathione peroxidase 7 (GPX7) gene expression, body temperature (BT) and creatine kinase (CK) activity were influenced by both selenium supplementation and HS. Aspartate aminotransferase (AST), alanine aminotransferase (ALT) activity and creatinine content all were influenced by the diet/environment interaction. The highest AST activity, ALT activity and creatinine levels were observed in animals that were both on the SD diet and exposed to HS. HS animals also exhibited an increased heterophil/lymphocyte ratio and lower triiodothyronine (T3) hormone levels than birds that remained at the comfortable temperature. Animals subjected to HS and fed with selenium supplemented diet showed better results regarding gene expression and, thus, better results for the activities of enzymes used as stress markers, which could be due to the higher antioxidant capacity provided by the action of the studied genes.

Two experiments were carried out to determine the levels of supplementation of inorganic selenium (Se) and vitamin E (VE) in diets of quails aged 0-14 and 14-35 days old. A completely randomized design was used in a factorial design (Se = 0.1125; 0.2250; 0.3375 and 0.4500 mg kg diet × VE = 10; 23; 36 and 49 IU kg diet ). In experiment 1, quail (n = 2,400) were aged 0-14 days and were divided into 16 treatments, with three replicates of 50 birds. In experiment 2, quail (n = 1,680) were aged 14-35 days and were divided into the same treatments, with three replicates of 35 birds. At age 0-14 days, the levels of VE did not affect performance (p > .05); however, the feed conversion (FC) was influenced by a quadratic effect (p = .0515), according to the level of Se, with a higher level estimated at 0.29 mg Se kg diet . At age 14-35 days, there was a linear effect with interaction (Se × VE), for FC (p = .0150) and weight gain (WG; p = .0266). FC (Se, p = .0048 and VE, p = .0019) and WG (Se, p = .0049 and VE, p = .0068) improved linearly with increasing levels of Se and VE. The feed intake (FI) decreased linearly (p = .0582) as a function of VE. The carcass yield showed a quadratic effect (p = .0056) on the levels of VE, with a higher yield estimation of 27.24 IU VE/kg of diet. It can be concluded that the optimum level of supplementation at age 0-14 days was 0.29 mg Se kg diet and 10 IU VE kg diet and at age 14-35 days, it was 0.4500 mg Se kg diet and 49 IU of VE kg diet .

 RESUMODois experimentos foram conduzidos com o objetivo de determinar a energia digestível da glicerina semipurificada vegetal e mista e o desempenho de coelhos em crescimento alimentados com dietas contendo os coprodutos. No ensaio de digestibilidade, foram utilizados 108 coelhos da raça Nova Zelândia Branco, com 45 dias de idade, distribuídos ao acaso em nove tratamentos (0, 4, 8, 12 e 16% de inclusão de glicerina vegetal e mista na dieta), com 12 repetições. Para o ensaio de desempenho, utilizaram-se 180 coelhos da raça Nova Zelândia Branco, dos 32 aos 70 dias de idade, distribuídos ao acaso em arranjo fatorial 2 x 4 (dois tipos de glicerina e quatro porcentagens de inclusão: 3, 6, 9 e 12%) mais uma dieta referência, com 10 repetições e dois animais por unidade experimental. Glicerinas vegetal e mista apresentaram energia digestível de 4.048 e 3.697kcal/kg MS, respectivamente. Entre 32 e 50 dias de idade dos coelhos, a dieta com 12% de glicerina mista prejudicou (P<0,05) o ganho de peso (32,14 g/dia), a conversão alimentar (3,57) e o custo por quilo de ganho de peso (R$ 2,08) em relação à dieta referência (39,42g/dia, 2,87 e R$1,69, respectivamente). Dos 32 aos 70 dias, o ganho de peso (30,11g/dia) e a conversão alimentar (3,99) dos animais que receberam 12% de glicerina mista na dieta foram piores (P<0,05) em relação aos da dieta referência (34,00g/dia e 3,65, respectivamente). Para as características de desempenho, dos 32 aos 70 dias, não foram verificadas diferenças (P>0,05) entre a inclusão de glicerina vegetal na dieta e a dieta referência, porém a maior viabilidade econômica (P<0,05) foi com 12% de inclusão (R$1,89 x R$2,15, respectivamente). A glicerina vegetal pode ser incluída em até 12% da dieta e a mista, em até 9%, diminuindo o custo de produção sem afetar o desempenho animal.Palavras-chave: coelho, conversão alimentar, custo, ganho de peso, transesterificação catalítica (0, 4, 8, 12 and 16% of (39.42g/day, 2.87 and R$ 1.69, respectively). From 32 to 70 days, weight gain (30.11g/day) and feed conversion (3.99) of the animals fed with the diet containing 12% of mixed glycerin were worst (P<0.05) in relation to the reference diet (34.00 g/day and 3.65, respectively). ABSTRACT Two trials were conducted with the goal of determining the digestible energy of vegetal and mixed semi purified glycerin and the performance of growing rabbits fed with diets containing the byproducts. In the digestibility assay 108 New Zealand White rabbits, 45 days old, were used, assigned in a completely randomized design into nine treatments

-An experiment was conducted to determine the required levels of supplementary vitamin D and calcium in meat-type quail (Coturnix coturnix sp) between 15 and 35 days old. The experiment was a 4 × 4 factorial design with four levels of calcium: 0.42, 0.58, 0.74, and 0.90% and four levels of vitamin D: 1,000; 2,000; 3,000; and 4,000 IU. Body weight and body weight gain increased linearly and feed conversion showed some linear improvement due to increased levels of Ca and vitamin D. The increased vitamin D levels resulted in a linear increase in feed intake. Calcium and vitamin D requirements in meat-type quail between 15 and 35 days of age is greater or equal to 0.90% Ca and greater or equal to 4,000 IU of vitamin D, probably because the experiment was conducted during the pre-laying phase.

An experiment was conducted to estimate the nutritional requirements of calcium ( Ca ) and available phosphorus ( aP ) for Japanese quails ( Coturnix coturnix japonica ) in the egg-laying stage (64–168 D). The experiment was an entirely randomized design, in a factorial scheme (Ca = 1.70, 2.40, 3.10, and 3.80% and aP = 0.15, 0.30, 0.45, and 0.60%), with 3 replicates and 10 quails per experimental unit. No interactions were found for quail body weight and daily feed intake ( DFI ) ( P > 0.05). However, body weight decreased linearly ( P < 0.05) as the levels of Ca increased, whereas DFI exhibited a quadratic effect ( P < 0.05) for both Ca and aP. The lowest values of DFI were estimated in 2.79 and 0.36% for Ca and aP, respectively. Egg production, egg mass, and feed conversion ratio per egg dozen presented significant interaction in which all of them had a quadratic effect ( P < 0.05), with estimations for maximum yield in feed containing 2.74, 2.71, 2.75, and 2.74% Ca and 0.40, 0.39, 0.39, and 0.40% aP. The concentration of Ca in the eggshell increased linearly as per the levels of Ca studied, having a quadratic effect for aP levels, with a maximum point of 0.44%. In relation to the bone parameters, there was a linear interaction for Ca and aP in bone density and bone resistance ( BR ) of the femur, with a quadratic effect in BD estimating 2.84 and 0.50% for Ca and aP, respectively. In BR, the estimation was 3.27% Ca, with linear increase for aP. The BR of the tibiotarso increased linearly as per the Ca levels, obtaining the same Ca concentration response in this bone. As conclusion, when considering the estimations obtained through overlapped contour plots, the best responses to the effects of Ca and aP on productive characteristics were estimated at 2.68% Ca and 0.38% aP to produce feed for egg-laying Japanese quails.

Three experiments were carried out to determine the crude protein requirements for maintenance (CPm) and weight gain (CPg) of meat quail and to develop protein‐requirement prediction models. Experiment 1 was conducted to determine CPm by the nitrogen‐balance technique. The regression of nitrogen balance on nitrogen intake revealed a CPm requirement of 2.94 g/kg0.75/day. Experiment 2 was aimed at determining CPm by the comparative‐slaughter technique. Retained nitrogen (RN) and nitrogen intake (NI) were quantified considering the metabolic weight of the birds. The linear regression of RN on NI provided a CPm estimate of 6.63 g/kg0.75/day. Experiment 3 was conducted to determine CPg. The regression of body nitrogen from the carcasses on fasted body weight revealed CPg estimates of 407.68 (0–7 days), 501.76 (8–14 days), 470.40 (0–14 days), 517.44 (15–21 days), 627.20 (22–28 days), 423.36 (29–35 days), and 517.44 mg/g (15–35 days). The protein‐requirement prediction models developed for meat quail aged 0–7, 8–14, 0–14, 15–21, 22–28, 29–35, and 15–35 days were CP = 2.94.W0.75 + 0.408.G; CP = 2.94.W0.75 + 0.502.G; CP = 2.94.W0.75 + 0.470.G; CP = 2.94.W0.75 + 0,517.G; CP = 2.94.W0.75 + 0.627.G; CP = 2.94.W0.75 + 0.423.G; CP = 2.94.W0.75 + 0.517.G, respectively, where: W0.75 =  metabolic weight (kg), and G =  daily weight gain (g).

SUMMARY This study aimed to evaluate biometric viscera and blood parameters of quails at 14 and 35 days of age, supplemented with different levels of inorganic selenium and vitamin E. A completely randomized design was used in a 4×4 factorial scheme (inorganic Se = 0.1125, 0.2250, 0.3375 and 0.4500 mg/kg diet x VE = 10, 23, 36 and 49 IU/kg feed). In the 0-14 days experiment, 2,400 newborn quail were used, distributed in 16 treatments and three replications of 50 birds each. In the 14-35 days experiment, 1,680 14 day-old quails were used with same treatments and three replicates of 35 birds each. At 14 days, the relative spleen weights (P=0.0203) increased linearly as a function of the VE level, while at 35 days, the relative weight of the bursa (P=0.0390) increased linearly as a function of Se concentration. At 14 days, there was a vitamin x mineral interaction (p=0.0097) affecting total cholesterol (TC), and a quadratic effect (P = 0.0138) related to Se and linear reduction levels (P=0.0275) as a function of VE. At 35 days, the TC concentrations (P=0.0055) and triglycerides (TG, P = 0.0220) showed a quadratic effect for Se. The linear increase in spleen weight and bursa after 14 and 35 days respectively suggests an improved immune response as a function of VE and Se supplementation. To achieve the lowest concentration of TC and TG at 35 days of age, supplementation of 0.26 and 0.29 mg/Se/kg/feed, respectively, is recommended.