Arginine and vitamin E improve the immune response after a Salmonella challenge in broiler chicks.

Two experiments were conducted to evaluate the effects of Arg, vitamin E (VE), and mannanoligosaccharide (MOS) on the immune response and clearance of Salmonella in broiler chickens. In each experiment, 1-d-old chicks (n = 160) were randomly distributed into 4 groups: antibiotic-free diet (negative control, CTL-), antibiotic-supplemented diet (positive control, CTL+), antibiotic free-diet plus Arg and VE (AVE), or antibiotic-free diet plus Arg, VE, and MOS (AVM). Birds were orally challenged with 10(6) cfu of a novobiocyn and nalidixic acid-resistant Salmonella enterica serovar Typhimurium strain at d 7 (experiment 1) or at d 3 (experiment 2). Heterophil- (HOB) and monocyte- (MOB) oxidative burst and lymphocyte proliferation (LPR), antibody titers, and Salmonella content in the ceca were measured at several intervals postinfection (PI). In experiment 1, both AVM and AVE decreased HOB compared with the controls 5 and 9 d PI, but increased LPR 9 d PI. In the same experiment, birds fed the AVE diet had higher MOB than birds fed CTL+ or the AVM diet at 7 d PI, whereas 9 d PI birds fed the AVM diet had the highest MOB. In experiment 2, birds fed the AVE diet had higher MOB, HOB, and LPR than birds in the other treatments 7 and 14 d PI, except at 7 d PI, when MOB was not different among treatments. Birds fed the AVM diet had the highest IgA antibody titer, and a higher IgM antibody titer than the CTL+ birds. In experiment 1, Salmonella Typhimurium content in the ceca was lower in birds fed the AVM diet compared with birds fed the CTL- diet 3 d PI, but later on (10 and 17 d PI), and in experiment 2 (7, 14, and 21 d PI), Salmonella Typhimurium concentrations were not different among treatments. Thus, Arg and VE improved immune response after a Salmonella Typhimurium challenge in young chicks, and although they did not reduce Salmonella Typhimurium concentrations in the ceca, they may improve bacterial resistance against other pathogens in commercial growing conditions.

Supplemental L-arginine and vitamins E and C preserve xanthine oxidase activity in the lung of broiler chickens grown under hypobaric hypoxia.

The effects of l-Arg, vitamin C (VC), and vitamin E (VE) on xanthine- (XO) and NAD(P)H-oxidase (NOX) activities, and nitric oxide (NO) availability of hypoxic broilers were evaluated. Chickens were kept in wire cages with free access to feed and water. One-day-old chicks were assigned to 1 of 3 diets: control (CTL; ME 3,200 kcal/kg, CP 23%), high Arg (HA; CTL + Arg 0.8%), or high Arg plus VE and VC (AEC; HA + 200 IU of VE/kg of feed + 500 mg of VC/L of water), and grown under hypobaric hypoxia (HYP) from d 7 to 30. A fourth group of birds was fed the CTL diet and grown under normoxia (CTL-NOR). At d 30, chickens were euthanized, their lungs fixed in vivo, excised, and processed for cyto- and histochemistry. The enzymes XO and NOX were localized and activities assessed histochemically and in lung homogenates. The NO depletion was assessed through nitrotyrosine immunocytochemistry colloidal gold particles (NTY). The XO and NOX localized in cell membranes and within vesicles of pulmonary vessel endothelial cells. The XO activity was higher in CTL-NOR birds (586 ± 43 reflectance units) than in both AEC-HYP (456 ± 39) and HA-HYP birds (394 ± 31), whereas CTL-HYP birds had the lowest XO activity (313 ± 27). The NO depletion was not affected by dietary or hypoxia conditions in clinically healthy birds; nevertheless, hypoxic birds that developed pulmonary hypertension had higher NTY levels (less NO, 145 ± 19) than hypoxic but clinically healthy birds (56 ± 11). Thus, the concurrent supplementation of Arg, VE, and VC restored XO activity without affecting NOX activity or NO availability. The dual role of XO, which produces superoxide and uric acid, may have buffered the effects of superoxide in broiler chickens grown under hypobaric hypoxia.

The effect of feeding excess arginine on lipogenic gene expression and growth performance in broilers.

1. Reducing excess fat accretion is important for both human health and animal production. The present study was conducted to investigate the effects of arginine (Arg) on the regulation of lipogenic gene expression and on growth performance. 2. One-d-old female broiler chicks (Ross, n = 192) were used in a completely randomised design with 4 dietary treatments in which diets included 100% (CTL), 153% (LArg), 168% (MArg) and 183% (HArg) of the recommended concentration of digestible Arg. 3. Results showed that high concentrations of Arg improved body weight gain, feed efficiency, meat production, fat and crude protein content of breast muscle and plasma thyroid hormones. Conversely, abdominal fat, cholesterol, triglyceride and urea were lower with higher concentrations of Arg. Dietary arginine increased lipogenic gene expression in muscles, while decreasing those in adipose tissue and liver. 4. It was concluded that increasing Arg in the diet reduced abdominal fat content, enhanced intramuscular fat and increased muscle and protein gain. Furthermore, Arg supplementation at the MArg concentration improved growth performance, and at HArg had the greatest effect on fat reduction.

Effects of arginine and antioxidant vitamins on pulmonary artery reactivity to phenylephrine in the broiler chicken.

The effects of supplemental l-arginine (Arg), vitamin E (VE), and vitamin C (VC) on vascular reactivity to phenylephrine (PE) were examined in clinically healthy hypoxemic male broiler chickens. One-day-old chicks were housed in wire cages and randomly allocated to 1 of 3 dietary treatments: control (CTL; n = 80; 3,200 kcal of ME/kg, 23% CP, 1.55% Arg and 40 IU of VE/kg of feed), high-Arg (HA; n = 40; CTL + 0.8% Arg), or high-Arg and high antioxidant-vitamin diet (AEC; n = 40; HA + 200 IU of VE/kg of feed and 500 mg of VC/kg of feed). At d 14, 40 CTL birds and all the HA and AEC birds had a primary pulmonary bronchus surgically occluded (PBO). Forty CTL broilers underwent surgery without occluding the bronchus (SHAM). Pulmonary artery (PA) rings were mounted for isometric tension recordings 14 to 21 d postsurgery. The HA-PBO and AEC-PBO PA were immersed in Krebs-Henseleit buffer plus a vehicle (VehCtl) or Krebs-Henseleit buffer plus supplemental Arg, or Arg, VE, and VC (A-E-C). Maximal contractile response to PE of the CTL-SHAM PA (16 ± 14 mg/mg of dry tissue) was one-tenth compared with that of the CTL-PBO PA (159 ± 13 mg/mg), whereas the PA contractility in the supplemented groups was one-ninth compared with those of the CTL-PBO (17.9 ± 13.0 mg/mg, 17.90 ± 13.0 mg/mg for the HA-PBO+Arg and AEC-PBO+A-E-C treatments, respectively). Supplementing the bath with Arg did not change the maximal response to PE compared with the vehicle control (16.7 ± 12.2 mg/mg for HA-PBO-VehCtl). However, supplementing the bath with A-E-C produced a one-fourth reactivity compared with that of the vehicle control (80.7 ± 13.0 mg/mg for AEC-PBO-VehCtl). The PBO increased PA reactivity to PE, but supplemental Arg plus VE and VC significantly reduced it. Differential reactivity responses to PE may have been the result of protective effects of Arg, VE, and VC, implicating oxidative stress in endothelial dysfunction as well as in the upregulation of smooth muscle contractility.

Dietary supplemented and meat-added antioxidants effect on the lipid oxidative stability of refrigerated and frozen cooked chicken meat.

The oxidation of fatty acids decreases the quality and shelf-life of meats. To reduce this process, dietary supplemented and meat-added antioxidants were evaluated on the lipid oxidative stability of cooked chicken meat. Broilers were fed 2 levels of vitamin E (10 or 100 mg•kg(-1) of feed; VE-10 and VE-100, respectively) or oregano essential oil (100 mg•kg(-1) of feed; OR-100). Additionally, honey (3%) or butylated hydroxytoluene (0.02%; BHT) were added to chicken meat from the control treatment (VE-10). Breast meat was ground, formed into patties, and cooked on electric grills until it reached an internal temperature of 74°C. Cooked meat was cooled at room temperature, packaged, and stored under refrigeration for 9 d (4°C) or frozen for 45 d (-20°C). The 2-thiobarbituric acid reactive substance test was used to quantify malondialdehyde (MDA) values in the meat. Data were analyzed using a repeated measures design, 5 treatments with 12 replications each, and the least squares means were compared with 4 orthogonal contrasts. The results showed that the meat of the VE-10 treatment had higher values of MDA (P ≤ 0.05) compared with the other antioxidant treatments in all the storage days. There were no differences (P ≥ 0.05) in MDA values between the dietary supplemented and meat-added antioxidant treatments. The meat added with honey had lower MDA values than the one with BHT (P ≤ 0.05). Meat of the VE-100 treatment showed lower MDA values than the one of OR-100 (P ≤ 0.05) in most storage days. In conclusion, supplementation of 10 mg•kg(-1) of vitamin E to the diet resulted in a higher development of lipid oxidation in the meat. Both dietary supplemented or meat-added antioxidants had similar effects on the lipid oxidative stability. The addition of honey maintained longer the lipid oxidative stability of the meat than BHT. Finally, dietary supplementation of vitamin E at the same level of oregano oil, 100 mg•kg(-1), resulted in a higher antioxidant effect on the meat.

Effects of dietary combination of n-3 and n-9 fatty acids on the deposition of linoleic and arachidonic acid in broiler chicken meats.

To minimize the amount of n-6 fatty acids in broiler chicken meat, 120 Cobb × Ross male broilers were divided into 6 different groups and fed a basal corn-soybean meal diet containing 5% fat from 5 different lipid sources: 1) a commercial mix of animal and vegetable oil, 2) soybean oil and olive oil (2.5% each), 3) flaxseed oil and olive oil (2.5% each), 4) flaxseed oil, eicosapentaenoic acid (C20:5; EPA; n-3), and olive oil (2.45, 0.05, and 2.5% respectively; FEO), 5) flaxseed oil, docosahexaenoic acid (C22:6; DHA; n-3), and olive oil (2.45, 0.05, and 2.5% respectively; FDO), and 6) fish oil and olive oil (2.5% each; FHO). At 6 and 9 wk, one bird per pen (4 pens per treatment) was processed, and liver, breast, and thigh samples were collected and used for fatty acid profiles or Δ6- and Δ9-desaturase mRNA gene expression levels. The deposition of linoleic acid (C18:2; n-6) or arachidonic acid (C20:4; n-6) was decreased in breast and thigh muscles of chickens fed n-3 fatty acids for 9 wk compared with chickens fed animal and vegetable oil and soybean oil and olive oil diets (P < 0.05). The addition of EPA to the diet (FEO; P > 0.05) did not reduce the deposition of linoleic acid and arachidonic acid as much as DHA (FDO; P < 0.05), and it suppressed the expression of Δ6- and Δ9-desaturase. When EPA and DHA were blended (FHO) and supplied to broiler chickens for 9 wk, EPA and DHA combination effects were observed on the deposition of LA and arachidonic acid in breast and thigh muscles. Thereby, the addition of a mixed EPA and DHA to a broiler chicken diet may be recommendable to reduce arachidonic acid accumulation in both broiler chicken breast and thigh meats, providing a functional broiler chicken meat to consumers.

Dietary combination effects of conjugated linoleic acid and flaxseed or fish oil on the concentration of linoleic and arachidonic acid in poultry meat.

This study was conducted to determine the effects of the combination of dietary conjugated linoleic acid (CLA) and n-3 fatty acids on the linoleic acid (C18:2n-6) and arachidonic acid (C20:4n-6) concentrations of broiler chicken breast and thigh muscles. One hundred and twenty broilers were raised to 6 wk of age. All chicks were fed a basal corn-soybean meal diet containing 5 different fat sources at an inclusion level of 2% total fat: 1) CLA, 2) flaxseed oil, 3) menhaden fish oil, 4) CLA and flaxseed oil, and 5) CLA and menhaden fish oil. Eight broilers from each treatment were processed at 4 and 6 wk of age. Breast and thigh muscle samples were collected and analyzed for total fat content and fatty acid composition. The results showed that broilers from the CLA and fish oil treatment had lower arachidonic acid concentrations in both breast and thigh muscles than those fed the flaxseed oil diet or the CLA and flaxseed oil diet (P < 0.05). The arachidonic acid concentration and n-6:n-3 ratio of breast and thigh samples from the menhaden fish oil diet were similar to those of the CLA and fish oil diet (P > 0.05), but the inclusion of linoleic acid into chicken thigh muscles of broilers fed the CLA and menhaden fish oil diet improved significantly when compared with that of the diet containing menhaden fish oil only. Thus, the combination of CLA and menhaden fish oil is recommended to reduce the concentrations of linoleic and arachidonic acids in broiler chicken breast and thigh muscles.

L-arginine and antioxidant vitamins E and C improve the cardiovascular performance of broiler chickens grown under chronic hypobaric hypoxia.

Two hundred broiler chicks were randomly assigned to 3 dietary treatments: control [CTL; 3,200 kcal of ME/kg, 23% CP, 1.55% Arg, and 40 IU of vitamin E (VE)/kg of feed], high-Arg (HA; CTL+0.8% Arg), or high-Arg and high antioxidant-vitamin diet (AEC; HA+200 IU of VE/kg of feed and 500 mg of vitamin C/L of water). The chicks were housed in wire cages in hypobaric chambers simulating 3,000 m above sea level. From d 28 to 42, clinically healthy birds were selected for cardiovascular performance (n=7 to 12/treatment). After surgery, pulmonary arterial pressure (PAP) and mean arterial pressure (MAP) readings were taken at 180, 120, and 60 s (basal values) before an epinephrine (EPI) challenge and then at 30, 60, 120, 180, 300, 600, and 1,200 s after the challenge, followed by a second EPI challenge with similar sample readings. There were no differences in the basal PAP values among chicken groups. The PAP increased within 30 s after both EPI challenges in all groups. It took 180 s after the first EPI challenge for the CTL chickens to return to the basal PAP values, whereas HA and AEC chickens returned to basal PAP values in 120 s. After the second EPI challenge, it took 60, 180, and 300 s for the AEC, HA, and CTL groups, respectively, to return to basal PAP values. The MAP response pattern to the EPI challenges mimicked that of PAP, but there were no differences among treatments in MAP at any sampling point. Supplemental Arg, VE, and vitamin C did not reduce ascites incidence in hypoxic broilers. In conclusion, supplemental Arg improved the pulmonary vascular performance of hypoxic broiler chickens and its effects were further improved by the addition of the antioxidant VE and vitamin C. Arginine and antioxidant vitamins may have played synergistic roles to increase NO bioavailability and reduce oxidative stress damage, thus improving cardiopulmonary performance.

Immune response of broiler chickens fed different levels of arginine and vitamin E to a coccidiosis vaccine and Eimeria challenge.

One-day-old broiler chicks (n = 300) were orally vaccinated (Coccivac-B) and divided into 6 groups to evaluate Arg at 3 levels of supplementation, 0, 0.3, or 0.6% [normal level (NARG), medium level (MARG), or high level (HARG), respectively], and 2 levels of vitamin E (VE), 40 or 80 IU/kg of feed (VE40 or VE80, respectively), in a factorial experiment. Birds were reared in floor pens with fresh pine shavings and provided a corn-soybean-based diet and water ad libitum. At d 14, all chickens were orally challenged with a mixture of Eimeria field isolates (Eimeria acervulina, Eimeria maxima, and Eimeria tenella). In vitro heterophil and monocyte oxidative burst (HOB and MOB, respectively) was measured at d 21 from cells isolated from peripheral blood. Antibody levels (IgG, IgM, and IgA isotypes, ELISA) and NO were measured at d 14 and 28. The HOB was lower in birds fed the VE40 diets but was increased with the MARG and HARG treatments, whereas birds fed the VE80 diet had a higher HOB irrespective of Arg level. Birds fed the VE80 diet had high levels of MOB, which was not further improved by Arg, whereas birds fed the VE40-MARG diet had the highest MOB response. Plasma NO was not affected by diet at d 14, but at d 28, plasma NO was higher in birds fed the VE80-MARG or the VE40-NARG diet and lower in birds fed the VE80-NARG or the VE40-MARG diet. Birds fed the VE40-HARG or VE80-MARG diet had the highest IgG levels at d 14, but at d 28, birds fed the VE80-MARG diet had the highest IgG levels. The IgM concentration was lower in birds fed NARG levels irrespective of VE levels at d 14, but at d 28, IgM levels were higher in birds fed the VE40-HARG or the VE80-MARG feed. The IgA concentration was not consistently affected at d 14 or 28. These results suggest that Arg and VE fed at levels higher than those recommended by the NRC may play complementary roles on the innate and humoral immune response against an Eimeria challenge, potentially improving vaccine efficacy and response to field infections.

Arginine and vitamin E improve the antibody responses to infectious bursal disease virus (IBDV) and sheep red blood cells in broiler chickens.

1. Dietary arginine (ARG) and vitamin E (VE) have been shown to improve immune responses in broiler chickens, but their combined effects have not been well documented. The objective of this study was to evaluate the combined effects of dietary ARG and VE on antibody responses to sheep red blood cell (SRBC, agglutination assay) inoculation in 13-d-old chicks, and antibody titres (ELISA) to infectious bursal disease virus (IBDV) before and after vaccination of 20-d-old chicks. 2. One-day-old broiler chicks were fed diets with normal (NARG, 12 g/kg of feed) or high (HARG, 22 g/kg of feed) inclusion rates of ARG, and three rates of VE (40, 80, or 200 mg/kg of feed; 40 mg being the supplement used in commercial diets) in a factorial arrangement. 3. Antibody titres to SRBC at 5, 8, and 12 d after inoculation were higher in chicks fed on the HARG diet than in those on NARG, and in chickens on VE80 compared with those on VE200 at 5, 8, and 12 d after inoculation. Antibody titres to the IBDV 2 days before and 19 d after vaccination were higher in chickens on HARG compared with those on NARG, and in chicks on VE80 compared to those on VE40 but similar to those on VE200. Conversely, 5 d after vaccination titres against IBDV were higher in chicks on NARG than in those on HARG, and in chickens on VE40 compared with those on VE80, yet similar to those on VE200. 4. These results show that diets with high ARG and high VE (80 mg/kg) improved the humoral-mediated immune response of broilers to IBDV and SRBC, suggesting it could be a strategy to improve vaccination protection and resistance to diseases.

Concurrent supplementation of arginine, vitamin E, and vitamin C improve cardiopulmonary performance in broilers chickens.

Two experiments were conducted to evaluate the effects of arginine, vitamin E (VE), and vitamin C (VC) on cardiopulmonary performance and ascites parameters of broilers reared under a cold environmental temperature. One-day-old male broilers were fed a basal corn-soybean meal diet (control, 1.2% arginine and 40 IU of VE), or the basal diet supplemented with 1% arginine and either 200 IU vitamin E (AE), 500 mg of vitamin C (AC), or a combination of VE and VC at the same amounts (AEC) per kilogram of feed. Pulmonary arterial pressure (PAP) and mean arterial pressure were recorded in clinically healthy, anesthetized birds (28 to 42 d old) before and after an epinephrine (Epi) challenge (0.5 mg/kg of BW, i.v.), an aminoguanidine hemisulfate challenge (100 mg/kg of BW, i.v.), and an N-nitro-l-arginine methyl ester challenge (50 mg/kg of BW, i.v.) at 20-min intervals. Data were analyzed by repeated measures ANOVA, and the Student Newman-Keuls test was used to separate means within groups. The PAP increased 30 s after the Epi challenge in all birds, but the peak PAP was lower in the AEC group than in all the other groups, whereas birds in the AE and AC groups had lower PAP peaks than did the control group. After 120 s of challenge, the PAP was lower in AEC birds compared with the other birds. The PAP returned to pre-Epi amounts within 300 s in all groups. The PAP was increased (P < 0.05) within 60 s after the aminoguanidine hemisulfate and N-nitro-l-arginine methyl ester challenges in all groups, but no differences were found among groups. The mean arterial pressure responses did not differ among groups. Plasma NO was greater in the AEC group than in all the other groups before and after the Epi challenge. These results showed that Epi elicited lower amplitude PAP and less prolonged increases in PAP in birds from the AEC group, and this may have been related to the increased vasodilation attributable to NO production. The AEC may have had complementary effects against oxidative stress, protecting the endothelium and preserving NO function.

Cecal populations of lactobacilli and bifidobacteria and Escherichia coli populations after in vivo Escherichia coli challenge in birds fed diets with purified lignin or mannanoligosaccharides.

Two experiments were conducted to evaluate lignin and mannanoligosaccharides as alternatives to antibiotic growth promoters in broilers. Dietary treatments for the 2 studies were 1) negative control (CTL-, antibiotic free); 2) positive control (CTL+, diet 1 + 11 mg of virginiamycin/kg); 3) mannanoligosaccharide (MOS; diet 1 + BioMos: 0.2% to 21 d and 0.1% thereafter); 4) LL (diet 1 + 1.25% Alcell lignin); and 5) HL (diet 1 + 2.5% Alcell lignin). In experiment 1, each treatment was assigned to 4 pen replicates (52 birds each). Body weight and feed intake were recorded weekly for 38 d. At 28 and 38 d, cecal contents were assayed for lactobacilli and bifidobacteria. Body weight and feed intake did not differ among dietary treatments. At d 38, the lactobacilli population was greatest (P < 0.05) in birds fed MOS, whereas LL-fed birds had greater (P < 0.05) lactobacilli load than those fed CTL+. Bifidobacteria load was greater (P < 0.05) in birds fed MOS or LL compared with those fed CTL+ at both d 28 and 38. However, at d 28 and 38, lactobacilli and bifidobacteria loads were lowest (P < 0.05) in CTL+ or HL-fed birds. In experiment 2, 21-d-old birds from the initial flock were transferred to cages for oral Escherichia coli (O2 and O88 serotypes) challenge (12 birds/treatment). After 3, 6, and 9 d, cecal loads of E. coli were determined. Birds fed HL had a lower E. coli load (P < 0.05) than birds fed CTL- or CTL+ at d 3, and lower than birds fed CTL- at d 6. At d 9, the E. coli load was lower (P < 0.05) in birds fed MOS or HL than in those fed the CTL- or CTL+ diets; LL-fed birds had lower E. coli load than those fed CTL-. Birds fed MOS or LL had a comparative advantage over CTL+ birds in increasing populations of lactobacilli and bifidobacteria and lowering E. coli loads after challenge.

Effects of vitamin E and L-arginine on cardiopulmonary function and ascites parameters in broiler chickens reared under subnormal temperatures.

Two experiments were conducted to evaluate the effects of arginine (Arg) and vitamin E (VE) on ascites (pulmonary hypertension syndrome) parameters, nitric oxide synthase (NOS) activity, and cardiopulmonary performance after an acute challenge with epinephrine (Epi). One-day-old male broilers (n = 100) were fed a commercial corn-soybean meal-based diet meeting NRC (1994) requirements, including 1.2% Arg and 40 IU of VE/kg. In experiment 1, birds were provided tap water (control), water with 0.3% Arg (HArg), water with 400 IU of VE/L (HVE), or a combination of both compounds (Arg-VE). In experiment 2, the treatment groups were similar but the VE was incorporated in the diet (400 IU/ kg of feed). At d 18, temperature was reduced to amplify the incidence of pulmonary hypertension. Body weight and hematocrit were recorded weekly. From d 28 to 42, cardiopulmonary performance was evaluated in clinically healthy, anesthetized birds (n = 7 to 8/treatment). A pulmonary artery and a systemic artery were cannulated, the birds were allowed to stabilize for 10 min (basal), an i.v. injection of Epi was applied (1 or 0.5 mg/kg of BW, experiment 1 and 2, respectively), and a second dose was applied 20 min later. Pulmonary arterial pressure (PAP), mean arterial pressure (MAP), and heart rate (HR) were recorded continuously and data were analyzed by repeated measures ANOVA. The NOS activity was estimated through the conversion of 14C-Arginine to 14C-citrulline in isolated pulmonary arteries. Right/total ventricular weight ratio (RV/TV) was recorded at the end of the experiment. Body weight, RV/TV, and hematocrit values were not significantly affected by the dietary treatments. The PAP increased (P < 0.01) within 30 s after Epi in all treatments, except the HArg treatment in experiment 2. Overall, the time taken for PAP to return to basal levels was longer in the Arg-VE birds and shorter in the HArg birds, particularly after the second challenge. However, although NOS activity was highly variable, birds fed HArg tended to have the lowest NOS activity of all groups. The levels of VE supplementation used in these experiments did not improve cardiopulmonary performance or NOS activity in isolated pulmonary arteries.

Taurine, cardiopulmonary hemodynamics, and pulmonary hypertension syndrome in broilers.

Previous studies have suggested cardiac taurine is released into the plasma in response to hypoxemia (low blood oxygen levels) during the pathogenesis of pulmonary hypertension syndrome (PHS, ascites). In the present study, broilers reared under cool temperature conditions (16 C) were provided tap water (control group), tap water supplemented with taurine, or tap water supplemented with the taurine transport antagonist beta-alanine. When compared with control values, taurine supplementation consistently elevated free taurine concentrations in the plasma but not in cardiac tissues, whereas beta-alanine supplementation consistently reduced free taurine concentrations in cardiac tissues but not in the plasma. Neither the incidence of PHS nor specific predictors of PHS susceptibility (electrocardiogram Lead II S-wave amplitude, % saturation of hemoglobin with oxygen, heart rate, right to total ventricular weight ratio) were affected by taurine or beta-alanine supplementation. Cardiopulmonary hemodynamic evaluations were conducted to compare control and beta-alanine supplemented broilers breathing room air or air containing 12% oxygen (low oxygen challenge). While breathing room air, the betaalanine-supplemented broilers had higher baseline values for cardiac output (186.2 vs. 146.9 mL/min/kg BW) and pulmonary arterial pressure (27.4 vs. 22.4 mm Hg), similar values for mean systemic arterial pressure (100 vs. 104 mm Hg) and pulmonary vascular resistance (0.062 vs. 0.064 resistance units), and lower values for total peripheral resistance (0.228 vs. 0.296 resistance units) when compared with control broilers breathing room air. During low oxygen challenges, the beta-alanine-supplemented broilers exhibited larger reductions in cardiac output, mean systemic arterial pressure, and pulmonary arterial pressure and greater increases in pulmonary vascular resistance than control broilers. These observations indicate that beta-alanine-supplemented broilers breathing room air had a higher systemic demand for oxygen as evidenced by their lower total peripheral resistance (systemic vasodilation) and had a capacity sufficient to pump a higher cardiac output and, thereby, maintain a similar mean systemic arterial pressure when compared with control broilers. However, cardiac function rapidly deteriorated in beta-alanine-supplemented broilers during low oxygen challenges, leading to substantially greater reductions in cardiac output, stroke volume, and mean systemic arterial pressure when compared with control broilers. Concurrent changes in pulmonary arterial pressure within the beta-alanine group reflect interactions between cardiac output and pulmonary vascular resistance. Overall, depleting cardiac taurine did not appear to initiate PHS, but systemic hypoxemia developing during the mid- to late-pathogenesis of PHS may expose and incipient cardiac weakness attributable to depleted taurine reserves.

Plasma levels of arginine, ornithine, and urea and growth performance of broilers fed supplemental L-arginine during cool temperature exposure.

Two experiments (Experiment 1 and 2) were conducted to evaluate growth performance, ascites mortality, and concentrations of plasma Arg, urea, and ornithine in male broilers raised in floor pens (2 x 4 factorial experiment, six pens for treatment) and exposed to cool temperatures averaging 16 C after 21 d of age. Broilers were fed low- or high-CP diets in both Experiments. In Experiment 1, Arg treatments consisted of control (no supplemental Arg); 0.15 or 0.3% supplemental Arg in the diet (low- and medium-Arg feed, respectively); and 0.3% supplemental Arg in the drinking water (Arg-water). Arginine levels were increased in Experiment 2 and consisted of the following: control (no supplemental Arg); 0.3 or 0.85% supplemental Arg in the diet (medium- and high-Arg feed, respectively); and 0.6% supplemental Arg in the drinking water (Arg-water). The water treatment followed a 3-d cyclic regimen, with supplemental Arg being provided for 24 h, followed by tap water for 48 h. When the broilers reached 37 d of age and all groups had consumed tap water for the previous 48 h, blood samples were collected from one bird per pen (Time 0, 0700 h); then supplemental Arg was provided in the Arg-water group, and additional blood samples were collected from the control and Arg-water groups at 3, 6, 12, and 36 h after Time 0. Plasma amino acids were analyzed using HPLC. Birds fed the high-CP diet were heavier at 49 d than birds fed the low-CP diet in Experiment 1, but not in Experiment 2. No differences were found in feed conversion or ascites mortality due to CP or Arg treatments in either experiment. In both experiments, plasma Arg was similar for all groups at Time 0, but increased in the Arg-water group at 3, 6, and 12 h after Arg was provided in the water. Within 12 h after returning to tap water, plasma Arg levels of the Arg-water group did not differ from the control group. Plasma urea and ornithine were parallel to plasma Arg concentrations, and the high-CP diets resulted in higher plasma levels of urea and ornithine compared with low-CP diets. These results indicate that kidney arginase was readily activated by Arg provided in the water, resulting in an immediate increase in plasma urea and ornithine. Plasma Arg was increased significantly, but no effects were observed in ascites mortality.