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.

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 b-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 (388C 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.

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.

Background This study evaluated the effects of Eimeria spp. challenge and dietary supplementation with free methionine or methionine dipeptide on animal performance; expression of genes associated with the immune system, antioxidant system, and amino acid transport in the jejunum; and redox status of the jejunum of broiler chickens. Methods A randomized, 2 × 3 factorial design was used, in which Eimeria spp . challenge was the first factor ( Eimeria -challenged, EC, or unchallenged, UC, broilers) and methionine supplementation was the second factor (non-supplemented, NS; free dl -methionine, dl -Met; and methionine dipeptide, dl -methionyl- dl -methionine, dl -MMet). At 14 days of age, chickens were inoculated orally with sporulated oocysts of Eimeria acervulina , Eimeria praecox , Eimeria maxima , and Eimeria mitis . Birds were killed by cervical dislocation 144 h post-inoculation (PI), and the jejunum was collected for biochemical and molecular analyses. Results EC broilers had a 13% lower feed intake (FI), 37% lower body weight gain (BWG), and 39% higher feed conversion ratio (FCR) than UC broilers. Chickens fed the dl -Met diet had higher BWG (about 12% higher) and better FCR (about 12% lower) than chickens fed the NS diet. EC chickens had lower relative weight of the bursa of Fabricius (51.8%) and higher relative weights of the spleen and whole intestine (53.6% and 26.3%, respectively) than UC chickens. Eimeria spp. challenge led to an increase in the levels of oxidative substances, such as nitrite and thiobarbituric acid reactive substances (TBARS), in the jejunum of chickens 144 h PI. Among UC chickens, those fed the dl -Met diet had higher total antioxidant capacity (TAC) and lower catalase (CAT) and superoxide dismutase (SOD) activities. EC chickens that received the NS diet had higher carbonylated protein content (CP). This result was associated with their lower TAC and catalase activity. The lower TAC in EC chickens might have been due to reduced expression of catalase ( CAT ) and superoxide dismutase 1 ( SOD1 ) genes. Chickens fed the dl -Met and dl -MMet diets had lower nitrite content. Eimeria spp. challenge suppressed neutral amino acid transporter 1 ( B 0 AT1) , peptide transporter 1 ( PEPT1) , toll-like receptor 5 ( TLR5) ...

This study aimed to develop extruded snacks including flour obtained from Nile tilápia carcasses, and then evaluate the chemical composition, colorimetry, thiobarbituric acid reactive substances, and microbiology. There was a significant increase in the levels of crude protein, ether extract, ash, and minerals, as well as a reduction in carbohydrates as more flour was included in the snacks. Increased levels of flavored flour caused reduction in the brightness of snacks. Oxidative rancidity was not detected in snacks. The inclusion of flour improved the nutritional value of extruded snacks without changing sensory characteristics. Microbiologically, the snacks are suitable for human consumption.

Current study evaluated the effect of pre-slaughter stress on serum cortisol levels, pH, colorimetry, water-holding capacity (WHC) and gene expression of ryanodine receptors (RyR1 and RyR3) in the Nile tilapia. A 3x4 factorial scheme experiment was conducted comprising three densities (100, 200, 400 kg/m³) with four transportation times (60, 120, 180, and 240 minutes).Transportation times alone reduced cortisol levels up to 180 minutes, followed by increased WHC and mRNA expression, RyR1 and RyR3 (200 kg/m³ density). No effect of density x transportation time interacted on the evaluated parameters. Results provided the first evidence that pre-slaughter stress affected ryanodine gene expression receptors and, consequently, the water-holding capacity in tilapia fillets.

The aim of the present study was to evaluate the effect of acute heat stress on the production of mitochondrial reactive oxygen species (ROS), the gene expression of the avian uncoupling protein (avUCP) and glutathione peroxidase (GPX 7), and the activity of the enzyme GPX in the liver of meat quail. Two groups of 15 meat quail (Coturnix coturnix japonica) that were 23 d of age were initially housed individually in metallic cages. A period of 7 d was provided for the 2 bird groups to adapt to the cages and to a thermoneutral environment at 25°C with 60% relative humidity. At 30 d of age, 15 quail were exposed to a heat stress (HS) treatment of 34°C for 24 h, humidity 60%, whereas control quail (n = 15) were kept at 25°C. To analyze the production of ROS, 4 quail from each treatment group were slaughtered, and their livers were collected for mitochondrial isolation and to measure the subsequent production of ROS by the mitochondria. Additionally, the livers of 6 animals from each treatment group were collected for total RNA extraction. The cDNA was amplified using primers specific for the target genes, and expression was analyzed using the real-time PCR reaction (qRT-PCR). Five animals from each treatment group were slaughtered to analyze glutathione peroxidase (GPx) activity, which was determined by using of hydrogen peroxide (H2O2), and based on measuring the amount nicotinamide adenine dinucleotide phosphate oxidized. A greater amount of mitochondrial ROS was found in HS animals (0.34 vs. 0.22 nm of ROS produced min(-1) · mg(-1) of protein, P < 0.05) for the reactions that contained only rotenone and in the reactions that were performed with rotenone and antimycin (0.31 vs. 0.23 nm of ROS produced min(-1) · mg(-1) of protein, P < 0.05). Concomitantly, the birds that were subjected to acute heat stress and had a greater amount of ROS production expressed less avUCP mRNA [0.75 arbitrary units (AU) vs. 0.87 AU, P < 0.05] and more GPX 7 mRNA (2.37 AU vs. 1.17 AU, P < 0.01). The HS quail displayed significantly greater GPx activity in their hepatocytes (47.8 vs. 39.6 nmol of NADPH oxidized per mg of protein per minute, P < 0.05). Thus, acute heat stress at 34°C for 24 h affects the production of mitochondrial ROS, the expression of avUCP and GPX 7 mRNA, and the activity of the GPx enzyme in the liver of meat quail.

We aimed to evaluate the effects of acute heat stress (HS) and age on the redox state in broilers aged 21 and 42 days. We evaluated the expression of genes related to antioxidant capacity, the production of hydrogen peroxide (H2O2), and the activity of antioxidant enzymes in the liver, as well as oxidative stress markers in the liver and plasma. The experiment had a completely randomized factorial design with two thermal environments (thermoneutral and HS, 38°C for 24 h) and two ages (21 and 42 days). Twenty-one-day-old animals exposed to HS showed the highest thioredoxin reductase 1 (TrxR1) (P<0.0001) and glutathione synthetase (GSS) (P<0.0001) gene expression levels. Age influenced the expression of the thioredoxin (Trx) (P=0.0090), superoxide dismutase (SOD) (P=0.0194), glutathione reductase (GSR) (P<0.0001) and glutathione peroxidase 7 (GPx7) (P<0.0001) genes; we observed greater expression in birds at 21 days than at 42 days. Forty-two-day-old HS birds showed the highest H2O2 production (222.31 pmol dichlorofluorescein produced/min×mg mitochondrial protein). We also verified the effects of age and environment on the liver content of Glutathione (GSH) (P<0.0001 and P=0.0039, respectively) and catalase (CAT) enzyme activity (P=0.0007 and P=0.0004, respectively). Higher GSH content and lower CAT activity were observed in animals from the thermoneutral environment compared with the HS environment and in animals at 21 days compared with 42 days. Broilers at 42 days of age had higher plasma creatinine content (0.05 v. 0.01 mg/dl) and higher aspartate aminotransferase activity (546.50 v. 230.67 U/l) than chickens at 21 days of age. Our results suggest that under HS conditions, in which there is higher H2O2 production, 21-day-old broilers have greater antioxidant capacity than 42-day-old animals.