Effects of free and dipeptide forms of methionine supplementation on oxidative metabolism of broilers under high temperature.

Our previous studies have shown that methionine supplementation could help to attenuate the effects of heat stress on the metabolism of broiler chickens. Here we investigated for the first time the effects of methionine supplementation in the form of DL-methionyl-DL-methionine on broilers subjected to heat stress during the growth phase. Broilers were divided into two groups; one group was reared under thermoneutral conditions and the other under continuous heat stress (30 ±â€¯1 °C, 60% relative humidity). Both groups were subdivided into three dietary treatments: a methionine-deficient (MD) diet, a diet supplemented with free methionine (DL-M), and a diet supplemented with methionine dipeptide (DL-MM). Broilers raised under chronic heat stress had lower feed intake and weight gain than broilers raised under thermoneutral conditions (P < 0.05). There were no differences in animal performance between methionine-supplemented diets (DL-M and DL-MM). Heat-stressed birds had significantly higher heterophil/lymphocyte (H/L) ratio than thermoneutral birds. Under heat stress, broilers fed DL-M and DL-MM diets had lower H/L ratio than birds fed the MD diet. Higher concentrations of carbonylated proteins and lower concentration of reduced glutathione were observed in broilers raised under heat stress. In comparing heat-stressed broilers, we found that birds fed the DL-M diet had lower concentrations of thiobarbituric acid-reactive substances and carbonylated proteins than those fed the MD diet (P < 0.05). Higher expression of glutathione peroxidase (GPX) and glutathione synthetase (GSS) genes was observed in heat-stressed broilers (P < 0.05). Under heat stress, the MD diet increased GPX expression compared with other diets. Under thermoneutral conditions, the DL-M diet resulted in the highest GSS expression. There was a negative correlation between DNA methylation and GPX and GSS expression. Our results showed that supplementation of broiler diets with free methionine or methionine dipeptide may help attenuate the effects of heat stress through enhanced activation of genes related to the glutathione antioxidant system. Methionine effects were found for gene regulation, gene expression, and post-translational processing.

Lippia gracilis Schauer essential oil as a growth promoter for Japanese quail.

The use of antibiotics as performance enhancers in animal feeding is declining, so Lippia gracilis Schauer essential oil (LGSEO) could be used as a potential substitute for the conventionally used growth promoters. The LGSEO contains components such as carvacrol and thymol, which kill and/or control pathogenic bacteria, increase population of beneficial organisms, act against oxidative processes and onto nutrient digestibility and absorption. The aim of this study was to investigate the action and the effects of LGSEO as a growth promoter in the diet of Japanese quail by examining their productive performance, intestinal microbiology, blood biochemical parameters, hepatic thiobarbituric acid reactive substances (TBARS) content and intestinal gene expression. A total of 252 two-day-old quail (Coturnix coturnix japonica) were assigned to 3 treatments in 7 replicates, using 12 birds per experimental unit. The treatments consisted of a basal diet, basal diet + LGSEO at 400 mg/kg of diet and basal diet + chemical antimicrobial (bacitracin methylene disalicylate) at 500 mg/kg of diet. The experimental period was 34 days. The highest feed intake (P < 0.01) was found in the group receiving the conventional antimicrobial, whereas the best feed conversion (P < 0.01) was shown by the animals receiving LGSEO. Escherichia coli growth was restricted in the quail receiving the growth promoters. Salmonella spp. growth was controlled by the treatment containing the conventional antimicrobial. There was no difference between the treatments (P > 0.05) for the concentration of aspartate aminotransferase and alanine aminotransferase enzymes in the blood or hepatic TBARS content. Birds receiving negative-control treatment exhibited a higher expression of sodium-glucose cotransporter (SGLT1), while those receiving the treatment with essential oil showed lower catalase (CAT) and glutathione peroxidase (GPX7) expressions compared to the conventional antimicrobial and control groups, respectively. Lippia gracilis Schauer essential oil is a powerful performance enhancer for Japanese quail by virtue of its abilities to improve their intestinal environment, balance the microbial population and reduce energy expenditure for oxidative processes.

Levels of supplementation of inorganic selenium and vitamin E for meat quail aged 0 to 14 and 14 to 35 days.

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-1  diet-1  × VE = 10; 23; 36 and 49 IU kg-1  diet-1 ). 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-1  diet-1 . 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-1  diet-1 and 10 IU VE kg-1  diet-1 and at age 14-35 days, it was 0.4500 mg Se kg-1  diet-1 and 49 IU of VE kg-1  diet-1 .

Effects of methionine hydroxy analogue supplementation on the expression of antioxidant-related genes of acute heat stress-exposed broilers.

We evaluated the effects of heat stress (HS) and methionine supplementation on biological markers of stress and expression of the genes for superoxide dismutase (SOD), thioredoxin (TRx), thioredoxin reductase 1 (TRxR1) and methionine sulfoxide reductase A (MsrA) in broilers aged 1 to 21 or 22 to 42 days. The broilers were divided into two treatments, one with the recommended level of methionine supplementation (MS, supplementation of dl-2-hydroxy-4-methylthiobutanoic acid (dl-HMTBA)) and one without methionine supplementation (MD). The animals were maintained at a temperature of thermal comfort or one of HS (38°C for 24 h). Mortality was only observed in 42-day-old broilers exposed to HS and fed the MD diet, and the rate was 5%. Starter period: we observed an interaction effect between diet and temperature on the gene expression of TRxR1 and MsrA, and expression of these genes was higher in the HS animals that received the MS diet than that in birds with the MD diet. Grower period: the expression of SOD, TRxR1 and MsrA genes, activities of aspartate aminotransferase (AST) and creatine kinase (CK) and content of creatinine were influenced by both study variables. In the HS animals, the expression of these genes, AST activity and creatinine content increased and CK activity decreased. In the animals on the MD diet, the expression of these genes and AST and creatinine values were higher and the CK activity was lower than those for the birds on the MS diet. Our results indicated that under HS conditions, the supplementation with dl-HMTBA could mitigate major damage caused by stress through the action on some genes related to TRx complex activity.

Níveis de suplementação de vitamina K para codornas de corte em crescimento de 15 a 35 dias de idade / Vitamin K supplementation for meat quail in growth of 15 to 35 days old

O presente experimento foi realizado com o objetivo de determinar os níveis de suplementação de vitamina K para codornas de corte. O delineamento experimental foi inteiramente ao acaso, com oito tratamentos, cinco repetições e 38 codornas por unidade experimental. Os níveis de suplementação de vitamina K foram: 0; 0,7; 1,0; 1,3; 1,6; 1,9; 2,2; 2,5mg/kg de ração. Não houve influência dos níveis de suplementação de vitamina K sobre o consumo de ração, peso corporal, ganho de peso, biomassa corporal acumulada e conversão alimentar, como também não foram alterados o peso, a densidade óssea, a resistência óssea e a concentração de cinzas no fêmur e na tíbia, o comprimento e o índice de Seedor do fêmur e o diâmetro da tíbia. O diâmetro e a concentração de cálcio no fêmur bem como o comprimento e a concentração de cálcio na tíbia responderam de forma quadrática (P<0,05), sendo os melhores níveis encontrados de 1,33; 1,42; 1,59 e 1,42mg de vitamina K, respectivamente. O tempo de protrombina, a concentração de cálcio no soro e a fosfatase alcalina também não foram afetados significativamente. Conclui-se que os níveis de suplementação não influenciaram o desempenho, portanto rações à base de milho e farelo de soja são suficientes para atender às necessidades de vitamina K das codornas nessa fase.(AU)

An experiment was carried out in order to determine the levels of vitamin K for meat quails. The experimental design was completely randomized with 8 treatments, 5 repetitions and 38 quails per experimental unit. The levels of vitamin K supplementation were 0; 0.7; 1.0; 1.3; 1.6; 1.9; 2.2; 2.5 mg/kg diets. There was no influence in the levels of vitamin K supplementation on feed intake, body weight, weight gain, biomass accumulated body and feed conversion. It also didn't affect the weight, bone density, bone strength and concentration of ash in the femur and tibial, length, index of Seedor femur and tibial diameter. Femur diameter and femur calcium concentration and the tibial length and tibial calcium concentration showed a quadratic response, with the highest levels found 1.33; 1.42; 1.59 and 1.42 mg of vitamin respectively. Prothrombin time, concentration of serum calcium and alkaline phosphatase levels also were not significantly affected. In conclusion, levels of supplementation did not influence the performance of meat quails, so diets based on corn and soybean meal are sufficient to meet the needs of the meat quails at this stage.(AU)

Effects of selenium supplementation on the oxidative state of acute heat stress-exposed quails.

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.

Effects of methionine supplementation on the redox state of acute heat stress-exposed quails.

The aims of the present study were to evaluate the possible effects of heat stress (HS) on H2O2 production and to evaluate whether methionine supplementation (MS) could mitigate the deleterious effects on cell metabolism and the redox state induced by oxidative stress. Meat quails (Coturnix coturnix coturnix) were fed a diet that either met the nutritional demands for methionine or did not meet this demand (methionine deficient [MD] diet) for 7 d. The animals were either kept at a thermal comfort temperature (25°C) or exposed to HS (38°C for 24 h, starting on the sixth day). Heat stress induced decreased food intake (P = 0.0140), decreased daily weight gain (P < 0.0001), and increased water intake (P = 0.0211). A higher rate of H2O2 production was observed in HS animals (0.0802 vs. 0.0692 nmol of reactive oxygen species [ROS] produced per minute per milligram of protein; P = 0.0042) and in animals fed with the MD diet (0.0808 vs. 0.0686 nmol of ROS produced per minute per milligram of protein; P = 0.0020). We observed effects of the interaction between diet and the environment on the activities of glutathione peroxidase (GP-x) and catalase (P = 0.0392 and P < 0.0001, respectively). Heat stress induced higher levels of GP-x activity in animals on the MS diet and higher catalase activity in animals on the MD diet. Glutathione (GSH) levels were higher in animals on the MS diet (P = 0.0273) and in animals that were kept in thermal comfort (P = 0.0018). The thiobarbituric acid reactive substances level was higher in HS animals fed with the MD diet (P = 0.0386). Significant effects of the interaction between supplementation and environment were observed on uric acid concentration levels, which were higher in HS animals fed the MS diet (P = 0.008), and on creatine kinase activity levels, which were lower in HS animals fed the MD diet (1,620.33 units/L; P = 0.0442). Our results suggest that under HS conditions, in which H2O2 production is increased, MS was able to mitigate ROS-induced damage, possibly by increasing the activities of antioxidant elements such as GSH, GPx activity, and uric acid concentration, which were present in higher levels in animals that were subjected to HS and fed the MS diet.

Acute heat stress and dietary methionine effects on IGF-I, GHR, and UCP mRNA expression in liver and muscle of quails.

This study evaluated the expression of insulin-like growth factor I (IGF-I), growth hormone receptor (GHR), and uncoupling protein (UCP) mRNA in muscle and liver of quails that were in thermal comfort or exposed to heat stress and that were fed diets with or without methionine supplementation. Meat quails were fed a diet that either met the nutritional demands for methionine (MS) or did not meet this demand (methionine-deficient diet, MD). The animals were either kept at a thermal comfort temperature (25°C) or exposed to heat stress (38°C for 24 h starting on the 6th day). RNA was extracted from liver and breast muscle, and cDNA was synthesized and amplified using quantitative reverse transcription-polymerase chain reaction. Animals that were fed the MS diet and remained at the thermal comfort temperature exhibited increased IGF-I mRNA expression in the liver (0.56 AU). The GHR mRNA expression in the liver and muscle was influenced by both the study variables. Animals receiving the MS diet showed higher GHR expression, while increased expression was observed in animals at the thermal comfort temperature. The UCP mRNA expression in the muscle was influenced by both methionine supplementation and heat stress. Higher expression was observed in animals that received the MD diet (2.29 vs 3.77 AU) and in animals kept in thermal comfort. Our results suggest that heat stress negatively affects the expression of growth-related genes and that methionine supplementation is necessary to appropriately maintain the levels of IGF-I, GHR, and UCP transcripts for animal metabolism.