Does the metabolizable energy influence the performance, carcass characteristics and biochemical parameters of European quails from 28 to 42 days of age?

This study was conducted to determine the metabolizable energy (ME) requirement for quails (Cortunix cortunix cortunix) from 28 to 42 days of age. Four hundred and twenty quails were distributed in a completely randomized design, with 5 treatments (2950, 3000, 3050, 3100 and 3150 kcal of ME/kg of feed), 7 replicates and 12 birds per experimental unit. Performance, relative weights of organs and viscera, carcass characteristics, meat quality, body composition and blood parameters of the birds were evaluated. There was a reduction in feed intake (ADFI) with the use of 3150 kcal ME/kg (p < 0.01), with a quadratic effect on feed efficiency (p < 0.01), estimating the energy requirement in the 3009.4 kcal ME/kg. The breast yield (BY) and the colour b* had an effect (p < 0.01), with better results for 2950 kcal ME/kg, while the meat texture reduced when the birds were fed with 3150 kcal ME/kg. HDL and LDL showed the quadratic effect (p < 0.01) when ME increased to 3111.6 and 3157.4 kcal/kg respectively. Very low density lipoprotein increased linearly (p < 0.01) in birds that received diets with 3000 kcal ME/kg. We conclude that the use of 3009.4 kcal of ME/kg for European quail meets the nutritional needs and provides an improvement in feed efficiency, without affecting the carcass parameters of the birds. Information regarding the nutritional requirements for European quails is still recent; therefore, it is essential to know the adequate levels of metabolizable energy, an important nutritional component for the maximum productive performance of birds.

Expression of genes related to antioxidant activity in Nile tilapia kept under salinity stress and fed diets containing different levels of vitamin C.

The aim of this study was to examine whether (1) severe changes in salinity produced increased stress, and (2) vitamin C supplementation might reduce the observed damage in Nile tilapia. The parameters measured included condition factor, survival rate, and gene expression of catalase (CAT), heat shock protein 70 (HSP70), glutathione reductase (GSR), glutathione synthase (GSS), and glutathione peroxidase (GPx). The investigation was conducted with 160 Nile tilapia divided into four treatment groups: freshwater; 7 or 21 parts per thousand (‰) salinity, all fed a basal diet; as well as a fourth treatment group consisting of fish kept at 21‰ salinity fed a diet supplemented with vitamin C (1500 mg/kg). For gene expression analysis, liver samples were collected after 24 h or after 14 d. After 24 h, fish raised in 21‰ salinity and fed with the diet supplemented with vitamin C showed similar GPx expression as the control freshwater group. GSS expression in 21‰ salinity was similar to fish exposed to 7‰ salinity. Nile tilapia exposed to 21‰ salinity without vitamin C supplementation exhibited the highest HSP70 gene expression levels after 24 h. After 14-dtreatment, the lowest survival rate was observed in the 21‰ salinity group. After 14 d, the highest expression of GPx and GSR levels was detected in fish in the 21‰ salinity group that received vitamin C. Data indicate that vitamin C supplementation enhanced the expression of genes related to antioxidant capacity in Nile tilapia exposed to higher salinity, thereby increasing protection against the oxidative effects induced by high water salinity..

Effects of methionine supplementation on the expression of oxidative stress-related genes in acute heat stress-exposed broilers.

The aim of the present study was to evaluate the effects of heat stress (HS) and methionine supplementation on the markers of stress and on the gene expression levels of uncoupling proteins (UCP), betaine-homocysteine methyltransferase (BHMT), cystathionine ß-synthase (CBS), glutathione synthetase (GSS) and glutathione peroxidase 7 (GPx7). Broilers from 1 to 21 d and from 22 to 42 d of age were divided into three treatment groups related to methionine supplementation: without methionine supplementation (MD); recommended level of methionine supplementation (DL1); excess methionine supplementation (DL2). The broilers were either kept at a comfortable thermal temperature or exposed to HS (38°C for 24 h). During the starter period, we observed the effects of the interaction between diet and environment on the gene expression levels of UCP, BHMT and GSS. Higher gene expression levels of UCP and BHMT were observed in broilers that were maintained at thermal comfort conditions and received the MD diet. HS broilers fed the DL1 and DL2 diets had the highest expression level of GSS. The expression levels of the CBS and GPx7 genes were influenced by both the environment and methionine supplementation. During the grower period, the gene expression levels of BHMT, CBS, GSS and GPx7 were affected by the diet × environment interaction. A higher expression level of BHMT was observed in broilers maintained at thermal comfort conditions and on the MD diet. HS induced higher expression levels of CBS, GSS and GPx7 in broilers that received the DL1 and DL2 diets. The present results suggest that under HS conditions, methionine supplementation could mitigate the effects of stress, since methionine contributed to the increased expression levels of genes related to antioxidant activity.

In vivo determination of domestic quail (Coturnix japonica) muscle development by ultrasonography as a function of energy levels.

The aim was to evaluate the growth and meat production and some meat quality characteristics of domestic quail (Coturnix japonica) as a function of metabolizable energy (ME) levels in the diet and to adjust predicting equations in ratio to area pectoralis major muscle of the carcass through the ultrasound. Two hundred and seventy mixed sex quail from 7 to 49 days old were distributed in three treatments (7 to 21 days old, diets with 2700; 2900 and 3100 kcal ME/kg; from 21 to 49 days, diets with 2900, 3050 and 3200 kcal of ME/kg), with five replications per treatment. Ultrasonography was performed at 21; 35 and 49 days of age in the pectoralis major muscle to determine prediction equations through multiple linear regression. Feed intake (FI) and feed efficiency (FE) were linearly influenced (P < 0.05) by energy levels in both phases evaluated. Regarding sensory analysis, there was no interference of ME levels on sensory attributes. The equation for predicting breast area was Y = 0.00271*ME + 0.25411*Age-9.58002, R2 = 74.25%. It is concluded that increasing the energy level of the feed from 2700 to 3100 kcal ME/kg reduces FI and improves the FE of quail. The increase in carcass fat from 35 days of age does not harm the physical and sensory characteristics of the meat. The ultrasonography in vivo of the M. pectoralis major, considering the age and energy level of the diet, made it possible to predict the pectoral muscle are a with higher reliability.

Calcium and available phosphorus requirements of Japanese quails in early egg-laying stage.

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.

Models for predicting protein requirements for meat quail.

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).

Effects of methionine supplementation on the expression of protein deposition-related genes in acute heat stress-exposed broilers.

The objective of this study was to evaluate the effect of heat stress and methionine supplementation on the gene expression of insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), phosphatidylinositol 3-kinase, and regulatory 1 (PI3KR1) in the liver, as well as the expression of the atrogin 1 and cathepsin L2 (CTSL2) genes in the breast muscle of broilers. Broilers from 1-21 and 22-42 days of age were divided into three treatments related to methionine supplementation as follows: without methionine supplementation (MD), recommended level of methionine (DL1), and excess supplementation of methionine (DL2). The animals were either maintained at a thermal comfort temperature or exposed to heat stress (HS) (38°C for 24 hours, starting on day 20 or day 41 for experiments 1 and 2, respectively). The heat stress increased the body temperature at both ages. Starter period: The HS animals presented increased plasma creatinine content (P<0.0001) and the highest CTSL2 gene expression (P<0.0001). The methionine supplementation increased the IGF-I (P = 0.0144) and GHR (P = 0.0011) gene expression and decreased the CTSL2 (P = 0.0004) and atrogin 1 (P = 0.0012) gene expression. Grower period: Significant effects for the interaction between supplementation and environment were observed for GHR (P = 0.0252) and CTSL2 (P = 0.0011) gene expression. The highest GHR expression was observed in animals that remained in thermal comfort on the DL2 diet, and the lowest expression occurred in the HS animals fed the MD diet. For CTSL2, the HS animals fed the MD diet presented the highest CTSL2 gene expression, and the lowest expression was observed in the animals maintained at thermal comfort on DL1 and DL2 diets. Only methionine supplementation had effect on atrogin-1 gene expression (P<0.0001), with higher methionine content in the diet lower atrogin-1 gene expression was observed. Our results suggest that heat stress induces greater protein degradation and that methionine supplementation could induce protein deposition because methionine increased the expression of genes related to protein synthesis and decreased the expression of genes related to protein breakdown.

Thermal stress induces changes in gene expression and blood parameters in high and low feed efficiency meat quail.

In this study, we analysed markers of stress, plasma creatinine and T3 content, and insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), uncoupling protein (UCP), adenine nucleotide translocase (ANT) and cytochrome c oxidase subunit III (COX III) mRNA expression in the liver and muscle of high (0.22 g/g) and low (0.14 g/g) feed efficiency (FE) meat quail at three different air temperatures, comfortable, heat and cold stress, for 24 h. High FE quail presented higher plasma T3 and lower creatinine levels. IGF-I mRNA expression was higher in the livers of high FE quail than in the livers of low FE quail under both comfortable and cold stress conditions. In the muscle, regardless of the environment, high FE birds showed higher IGF-I mRNA expression. High FE birds also showed higher GHR mRNA expression under comfortable conditions. Regarding the environment, higher expression was observed in birds at comfortable conditions, and lower expression in birds under heat stress. UCP mRNA expression in the liver was lower in high FE birds and higher under heat stress compared with the other conditions. Low and high FE birds showed greater ANT mRNA expression in the muscle under cold stress. Greater mRNA COX III expressions were observed in the liver and muscle of quails under comfortable conditions. Our results suggest that temperature affects the expression of genes related to growth and mitochondrial energy production, and quail with different FEs respond differently to environmental stimuli. In comfortable conditions, high FE animals show higher IGF-I mRNA expression and plasma T3 and lower creatinine content.