Role of Selenium from Different Sources in Prevention of Pulmonary Arterial Hypertension Syndrome in Broiler Chickens.

Pulmonary arterial hypertension (PAH) syndrome in broilers is associated with hypoxia, which prevails at high altitude. Oxidative stress is the pathogenic mechanism underlying PAH. Because selenium is key element in the structure of antioxidant enzymes, we evaluated pulmonary hypertensive responses in broiler chickens fed with diets supplemented with organic or nano-selenium. One hundred forty-four broilers (starting at 5 days old) were fed with (i) control group: birds received a standard diet; (ii) nano-selenium group: birds were fed with basal diet supplemented with nano-selenium at 0.3 mg/kg; and (iii) organic selenium group: birds received basal diet supplemented with organic selenium at 0.3 mg/kg. We assessed growth performance, carcass characteristics, antioxidant variables, blood parameters, and small intestine morphology. Although Se supplementation did not affect growth performance, carcass traits, and organ weight (P > 0.05), the right to total ventricular weight ratio (RV:TV), malondialdehyde concentration in the liver, and heterophil to lymphocyte ratio were significantly lower in the nano-selenium group relative to the control (P < 0.05). Chickens that received nano-selenium also elicited significantly higher antibody titers after 24 h of an injection of sheep red blood cells (P < 0.05). Nano-selenium supplementation also significantly increased villus height, absorptive surface area, and lamina propria thickness relative to the control (P < 0.05) in different segments of the small intestine. In contrast, organic selenium supplement improved intestinal morphometry only in the jejunum. We conclude that dietary supplementation of 0.30 mg/kg nano-selenium could prevent right ventricular hypertrophy as reflected by reduced RV:TV, reduced levels of lipid peroxidation in the liver, and improved gut function.

Pulmonary hypertension and right ventricular failure in broiler chickens reared at high altitude is affected by dietary source of n-6 and n-3 fatty acids.

The present study evaluated the development of pulmonary hypertension and right ventricular failure in broiler chickens reared at high altitude (2100 m) as affected by dietary intake of n-3 and n-6 fatty acid sources. Flax oil and soy oil were used as sources of n-3 and n-6 fatty acids, respectively, either with or without α-tocopheryl acetate. A total of 192 day-old broiler chicks (Ross 308) were used in a completely randomized design using isoenergetic and isonitrogenous experimental diets. Results showed that dietary flax oil significantly (p < 0.05) improved feed conversion ratio during 21-42 days of age. However, body weight gain did not significantly differ among the experimental groups in entire trial. Birds received flax oil had significantly higher serum concentration of nitric oxide (NO) but they had lower serum concentration of malondialdehyde when compared with their counterparts fed with soy oil. Liver and abdominal fat weights were significantly (p < 0.05) reduced by substitution of soy oil for flax oil. The right-to-total ventricle weight ratio (RV/TV) and mortality from pulmonary arterial hypertension (PAH) were significantly (p < 0.05) decreased in birds that received flax oil. In conclusion, n-3 fatty acids could significantly reduce RV:TV and PAH mortality in birds by increasing circulatory level of NO and suppressing hepatic lipogenesis.

Antioxidant supplementation of low-protein diets reduced susceptibility to pulmonary hypertension in broiler chickens raised at high altitude.

A reduced-protein diet (designated as RPD) was prepared and its effects on growth performance and the development of pulmonary hypertension syndrome (PHS) were evaluated in broiler chickens compared to a normal-protein diet (designated as NPD) or to the RPD supplemented with CoQ10 alone (30 mg/kg) or in combination with vitamin E (30 mg/kg CoQ10 + 100 mg/kg vitamin E). The RPD had 30 g/kg less crude protein compared to the NPD. A total of 208 1-day-old male broilers (Ross 308 strain) were used in a 42-day trial. Serum concentrations of uric acid (UA) and nitric oxide (NO) significantly (p < 0.05) declined when chickens fed on the RPD. However, supplementing RPD with the antioxidants significantly (p < 0.05) increased the serum NO concentration. Although serum malondialdehyde (MDA) concentration was significantly (p < 0.05) higher in the RPD than the NDP, supplementing RPD with CoQ10 and CoQ10 + VE decreased serum MDA concentration to similar levels found in the NPD. Significant overexpression in GPX1 gene observed in the heart and lungs of broilers fed on the RPD, which was effectively restored by supplementation of CoQ10 . The right to total ventricular weight ratio (RV:TV) was significantly (p < 0.05) increased in birds fed the RPD, which concurred with an increase in mortality from pulmonary hypertension syndrome (PHS). However, a significant decline in mortality from PHS was observed when birds on RPD received CoQ10 or CoQ10 + VE. In conclusion, antioxidant supplementation effectively improves pulmonary hypertensive response in broiler chicken fed of reduced-protein diets.

L-arginine supplementation of reduced-protein diets improves pulmonary hypertensive response in broiler chickens reared at high altitude.

This study was conducted at high altitude (2100 m above sea level). A total of 208 d-old male broilers (Ross 308) were randomised across 16 floor pens and reared up to 42 d. A normal-protein diet (NPD) was formulated according to the National Research Council. A reduced-protein diet (RPD) was prepared with dietary protein reduced by 30 g/kg relative to that of the NPD. Two additional diets were prepared by adding 2 and 4 g L-arginine (ARG)/kg to the RPD. At the end of trial (42 d), blood sampling was done and carcass characteristics were recorded. ARG supplementation of the RPD at 4 g improved feed:gain in the growing stage and throughout the trial compared with the RPD. The right-to-total ventricular weight ratio was significantly increased in birds fed on RPD compared with those fed on NPD or ARG-supplemented RPD. Feeding RPD caused a significant decrease in plasma concentrations of nitric oxide (NO) and uric acid. Plasma NO level, however, was restored by ARG supplementation of RPD. ARG supplementation of RPD, however, significantly reduced the rate of pulmonary hypertension syndrome mortality compared to the negative control fed on RPD.

Effects of supplementation of canola meal-based diets with arginine on performance, plasma nitric oxide, and carcass characteristics of broiler chickens grown at high altitude.

A total of 300 male broilers (Ross 308) were exposed to cool conditions at high altitudes to study the effects of dietary Arg supplementation on performance and physiological and zootechnical variables. A corn-soybean meal (SBM) and a corn-canola meal (CM) diet were formulated for the starting (1 to 3 wk of age) and growing (3 to 6 wk of age) stages according to NRC recommendations. Two additional diets were prepared by supplementing 0.2 and 0.4% l-Arg to the corn-CM diet. Substitution of CM for SBM caused a significant (P < 0.05) reduction in weight gain and feed intake and resulted in impaired feed:gain. Supplementing Arg in the CM diet restored the feed and weight losses to a significant extent so that a significant difference was found between CM diet and CM + 0.4% Arg in terms of weight gain for the growing (3 to 6 wk) stage and the entire study (1 to 6 wk; P < 0.05). Total plasma nitric oxide (NO) concentration analyzed by nitrate plus nitrite assay was measured in the treatment groups. A significant (P < 0.05) decrease in plasma NO level was observed by substituting CM for SBM in the diet. Supplementing the CM diet with Arg increased the plasma NO level above that of SBM group. Carcass and breast yields were significantly decreased (P < 0.05) as a result of substituting CM for SBM. The substitution of CM for SBM, however, significantly (P < 0.05) increased the proportions of thighs and heart. The right ventricular weight:total ventricular weight ratio and ascites mortality showed a significant (P < 0.05) increase when SBM was replaced by CM in the diet. Fortification of the CM diet with Arg eliminated the significant difference in the right-to-total ventricular weight ratios when compared with the SBM diet. In conclusion, feeding CM to broiler chickens raised at high altitude caused reduced growth performance and predisposed the birds to pulmonary hypertension and ascites, which were partly restored by Arg supplementation.

Oral supplementation with vitamin C improves intestinal mucosa morphology in the pulmonary hypertensive broiler chicken.

1. The aim of this study was to determine the effects of added dietary vitamin C on the intestinal mucosa morphology in pulmonary hypertensive broiler chickens. 2. One-day-old chickens were reared at high altitude and treated with 400, 800 or 1200 mg vitamin C/l of drinking water for 48 d. Segments from the duodenum, jejunum and ileum were collected for morphometric analysis. 3. The duodenum and jejunum villus height, width, surface area and lamina propria thickness were greater in the highest vitamin C-treated groups compared to controls. 4. There were significant variations only in villus types of the jejunum and ileum: increased proportions of leaf + tongue-like villi and decreased proportions of convoluted + ridge-like villi at day 36 at the groups with 400 and 800 mg vitamin C/l. 5. It was concluded that vitamin C improves the gut morphology of the pulmonary hypertensive broiler chickens.