Effect of vitamin E and alpha lipoic acid on intestinal development associated with wooden breast myopathy in broilers.

Intestinal development is closely associated with inflammatory wooden breast (WB) myopathy. Vitamin E (VE) and alpha lipoic acid (ALA) with antioxidant and anti-inflammatory effects were used independently and in combination to evaluate their effects on intestinal developmental changes in ileal morphology and expression of genes related with gut nutrient transport, structure, and inflammation in broilers during the first 3 wk posthatch. A total of 160 newly hatched Ross 708 broiler chicks were randomly assigned into a control and 3 dietary treatments with 10 replicates of 4 birds each. Supplementation of VE (160 mg/kg) and ALA (500 mg/kg) independently and in combination were fed during the first 3 wk. At 1, 2, and 3 wk of age, one chick from each pen was harvested. Plasma VE concentration and ileal morphology were determined. Gene expression was measured by real-time quantitative PCR. Broilers in VE and combination of ALA and VE group had higher plasma VE concentration than the control and ALA group at 1, 2, and 3 wk of age (P < 0.01). All dietary treatments increased ileal villus height at 1 wk of age (P < 0.01) and decreased intraepithelial lymphocytes at 3 wk of age compared to the control (P ≤ 0.05). Combination of VE and ALA increased collagen type IV alpha 1 chain expression (P ≤ 0.05) and improved basement membrane structure indicating increased gut basement membrane integrity at 2 and 3 wk of age compared to the control. Expression of lipopolysaccharide-induced tumor necrosis factor-alpha factor associated with inflammation was decreased in all dietary treatments at 3 wk of age compared to the control (P < 0.01). Ileal morphology and gene expression were closely correlated with breast muscle morphology and gene expression. These results suggest that VE and ALA especially when they were combined in the diet had positive effects on mitigating intestinal inflammation and improving nutrient transport beginning at 1 wk of age, which is likely critical in reducing the severity of WB.

Dietary taurine supplementation ameliorates muscle loss in chronic heat stressed broilers via suppressing the perk signaling and reversing endoplasmic reticulum-stress-induced apoptosis.

BACKGROUND: Heat stress seriously affects animal health and induces enormous financial losses in poultry production. Exploring the appropriate means for ameliorating unfavorable effects caused by heat stress is essential. We investigated whether taurine supplementation could attenuate breast muscle loss in chronic heat-stressed broilers, as well as its mechanism. We designed three groups: a normal control group (22 °C), a heat stress group (32 °C) and a taurine treatment group (32 °C, basal diet + 5 g·kg-1 taurine). RESULTS: We found that taurine significantly moderated the decreases of breast muscle mass and yield, as well as the increases of serum aspartate aminotransferase activity and serum urine acid level in chronic heat-stressed broilers. Additionally, supplementary taurine significantly alleviated elevations of the cytoplasm Ca2+ concentration, protein expressions of GRP78 and p-PERK, mRNA expressions of Ca2+ channels (RyR1, IP3R3) and endoplasmic reticulum (ER) stress factors (GRP78, GRP94, PERK, EIF2α, ATF4, IRE1, XBP1, ATF6 and CHOP), apoptosis (Caspase-3 and TUNEL), protein catabolism, and the reduction of taurine transporter (TauT) mRNA expression in the breast muscle induced by chronic heat stress. CONCLUSION: Supplementary taurine could attenuate chronic heat stress-induced breast muscle loss via reversing ER stress-induced apoptosis and suppressing protein catabolism. © 2020 Society of Chemical Industry.

Flavonoid bioactive compounds of hawthorn extract can promote growth, regulate electrocardiogram waves, and improve cardiac parameters of pulmonary hypertensive chickens.

The effect of orally administered hawthorn flavonoid extract (HFE) on growth, electrocardiographic waves, and cardiac parameters of pulmonary hypertensive chickens reared at high altitude (2,100 m above sea level) was examined. A total of 225 one-day-old, mixed broiler chicks (3 treatments with 5 replicates and 15 chicks per each, totally 75 birds/treatment) were assigned to 3 experimental groups: 0, 0.1, and 0.2 ml of HFE per 1 L of drinking water. Birds were administered the drinking water HFE treatments for 42 D. At an age of 28 and 42 D, electrocardiograms were undertaken and cardiac parameters such as the RV:TV, RV:BW, and TV:BW, and indicators of PHS on selected birds were measured. The final BW of chickens receiving the HFE at 0.2 ml/L was greater (2,579 ± 64 g) than that of birds receiving 0.1 ml/L (2,497 ± 62 g) and 0 ml/L (2,323 ± 57 g). Therefore, no supplemented group had a lower final BW than others (P < 0.05). Amplitudes of S and T waves in 0.1- and 0.2-ml/L HFE consumed groups at 28 and 42 D of age decreased compared with that in the control group (P < 0.05). The HFE reduced the heart weight and RV:TV, RV:BW, and TV:BW ratios when supplemented in drinking water at 0.1 and 0.2 mL/L compared with 0 mL/L (P < 0.05). In conclusion, supplementation of HFE in drinking water can reduce the PHS and incidence of cardiac disorders. Owing to the positive effect of HFE on cardiac parameters that mediated through flavonoids bioactive compounds, this product can be used to prevent complications of pulmonary hypertension and disarray of electrocardiographic waves in broiler chickens reared at high altitude.

Intestinal gene expressions in broiler chickens infected with Escherichia coli and dietary supplemented with probiotic, acidifier and synbiotic.

In this study, we investigated the effects of probiotic, acidifier and synbiotic supplementation on growth performance, mortality rate, intestinal gene expressions, fecal shedding, and organs colonization induced by Escherichia coli in broiler chickens. Six experimental groups were included; negative control group (NC), positive control group (PC), probiotic group (PR), acidifier group (AC), synbiotic group (SY) and colistin sulfate group (CS). Chickens in groups NC and PC were fed a basal diet, while chickens in groups PR, AC, SY, and CS were fed a basal diet containing probiotic, acidifier, synbiotic and colistin sulfate, respectively from the 1st day to the 28th day of age. At 7 days of age, all groups (not NC) were orally challenged with 0.5 ml (1.0 × 109 CFU/ml) E. coli O78. The dietary supplementation of acidifier and synbiotic were sufficient to quell the devastating effects of E. coli infection in broilers. Growth performances represented by body weight gain, feed intake and feed conversion ratio were significantly improved as well as, mortalities were prevented whilst the ileal pro-inflammatory gene expressions (IL-6, IL-8, IL-13, TLR-4, IFN-γ, LITAF, AvBD-2, and AvBD-9) were significantly downregulated and the anti-inflammatory cytokine (IL-10) was significantly increased. In addition, E. coli fecal shedding and organs colonization was significantly diminished. It was concluded that the addition of both acidifier and synbiotic to the diet of broilers infected with E. coli could modulate the intestinal inflammatory responses induced by E. coli infection and minimized the inflammation-induced damage which resulted in improvement in growth performance, prevention of mortalities and reduction of E. coli environmental contamination.

Dietary taurine supplementation decreases fat synthesis by suppressing the liver X receptor α pathway and alleviates lipid accumulation in the liver of chronic heat-stressed broilers.

BACKGROUND: Chronic heat stress can enhance fat synthesis and result in lipid accumulation in the liver of broilers. To investigate the effects and molecular mechanisms of dietary taurine supplementation on fat synthesis and lipid accumulation in the liver of chronic heat-stressed broilers, 144 28 day-old chickens (Arbor Acres) were randomly distributed to normal control (NC, 22 °C, basal diet), heat stress (HS, consistent 32 °C, basal diet), or heat stress plus taurine (HS + T, consistent 32 °C, basal diet +5.00 g kg-1 taurine) groups for a 14-day feeding trial. RESULTS: Compared with those of the HS group, dietary taurine supplementation significantly decreased the level of very-low-density lipoprotein and the activity of aspartate aminotransferase in plasma and the relative weight of liver in the HS + T group. In addition, dietary taurine supplementation also significantly decreased the levels of triglyceride, acyl-CoA carboxylase (ACC) and fatty acid synthase (FAS), and suppressed the mRNA expression levels of liver X receptor α (LXRα), sterol response element-binding protein 1c, ACC and FAS in the liver of chronic heat-stressed broilers. Meanwhile, dietary taurine supplementation effectively alleviated lipid accumulation in the liver of broilers exposed to chronic heat stress. CONCLUSION: Chronic heat stress significantly increased fat synthesis and resulted in excess lipid deposition in the liver of broilers. Dietary taurine supplementation can effectively decrease fat synthesis by suppressing the LXRα pathway and alleviate lipid accumulation in the liver of chronic heat-stressed broilers. © 2019 Society of Chemical Industry.

Effects of Dietary Supplementation of Probiotic Mix and Prebiotic on Growth Performance, Cecal Microbiota Composition, and Protection Against Escherichia coli O78 in Broiler Chickens.

The current study conducted to investigate the effects of a multi-strain commercial probiotic mix and prebiotic (isomaltooligosaccharide, IMO) on broiler performance parameters, cecal microbiota composition, and protection against challenge with avian pathogenic Escherichia coli (APEC) O78. For this purpose, 101-day-old Cobb chicks were randomly allocated into four experimental groups (G)-G01: basal diet, G02: basal diet and challenged with E. coli O78 at 28 days old, G03: basal diet with probiotic mix and challenged with E. coli O78 at 28 days old, and G04: basal diet with IMO and challenged with E. coli O78 at 28 days old. Results showed that weekly body weights in G03 were heavier (P < 0.05) than those of G01 and G02 at the fourth and fifth week. The body gain at the fourth and fifth week was higher (P < 0.05) in G03 than those of the other groups. The hot carcass weight (g) was significantly higher in broiler chickens kept in G03 and G04 compared with those in the control groups (G01 and G02). The probiotic mix and IMO significantly increased the total lactobacilli and total lactobacilli-enterococci populations in the ceca of treated broilers, respectively compared with those in the control groups. The treated broilers (G03 and G04) also showed lower mortality percentage and E. coli recovery rates the liver and spleen than those in G02. It was concluded that probiotic mix or IMO significantly improved the growth performance and modulated the intestinal microbiota of broiler chickens challenged with APEC O78.

Dietary inclusion of mushroom (Flammulina velutipes) stem waste on growth performance and immune responses in growing layer hens.

BACKGROUND: Medicinal mushrooms contain biologically active substances that can be used as an immune-modulating agent in poultry. The present study aimed to investigate the effects of Flammulina velutipes mushroom waste (FVW) on performance, immune response and serum immunity in growing layer hens. RESULTS: No significant differences (P > 0.05) were observed with respect to average daily feed intake, body weight gain and feed conversion ratio among the experimental groups during the entire study period (1-70 days). Antibody titers against Newcastle disease and infectious bronchitis were higher (P < 0.05) in the FVW fed groups than in the control and antibiotic groups. On day 28, serum immunoglobulin (Ig)A and IgG were higher (P < 0.05) in the 6% FVW group than in the control and antibiotic fed groups. On day 70, serum IgA was higher (P < 0.05) in FVW fed groups than in the control group; IgG was higher (P < 0.05) in the FVW groups than in the control and antibiotic groups. However, IgM was higher (P < 0.05) in both the 4% and 6% FVW groups than in the control and antibiotic groups for both experimental periods. Serum cytokine interleukin (IL)-2 and tumor necrosis factor-α concentrations were significantly higher (P < 0.05) in both the 4% and 6% FVW grousp than in the control and antibiotic groups; IL-4 was significantly higher (P < 0.05) in the FVW groups than in the control group; and IL-6 was significantly higher (P < 0.05) in the 6% FVW group than in the control and antibiotic groups. CONCLUSION: FVW at the 6% level can be used as a potential phytogenic feed stuff in growing layer hen rations with respect to improving the immune response without affecting normal weight gain. © 2018 Society of Chemical Industry.

The effect of different dietary levels of DL-methionine and DL-hydroxy analogue on the antioxidant status of young turkeys infected with the haemorrhagic enteritis virus.

BACKGROUND: The results of experiments involving broiler chickens and turkeys indicate that increased dietary methionine (Met) levels may improve the antioxidant protection of tissues in fast-growing birds. This is an important consideration since viral infections induce oxidative stress. The aim of this study was to verify the hypothesis that turkey diets with increased Met content can suppress oxidation processes induced by infection caused by the haemorrhagic enteritis virus (HEV), and that the noted effect is determined by the chemical form of this amino acid: DL-methionine (DLM) or DL-hydroxy analogue of Met (MHA). RESULTS: Dietary Met content above 40% higher than the level recommended by the NRC (1994) intensified lipid peroxidation in the small intestine, leading to an increase in malondialdehyde (MDA) and lipid peroxide (LOOH) levels, but it also stimulated antioxidant mechanisms in the blood and liver of turkeys infected with HEV. In comparison with DLM, MHA contributed to more severe symptoms of oxidative stress, such as elevated MDA levels in the intestines, and a decrease in glutathione peroxidase (GPx) activity and ferric-reducing ability of plasma (FRAP). CONCLUSIONS: In HEV-infected turkeys, diets with increased Met content did not exert a clear antioxidant effect, which was noted in uninfected birds. The prooxidant activity of Met observed in the small intestinal wall was suppressed in the blood and liver of turkeys, most likely due to intensified synthesis of uric acid and glutathione. In comparison with MHA, DLM had a more beneficial influence on the analysed parameters of the redox status in the small intestine, blood and liver of turkeys.

Does selection for growth rate in broilers affect their resistance and tolerance to Eimeria maxima?

Chickens exhibit varied responses to infection with Eimeria parasites. We hypothesise that broilers selected for increased growth rate will show lower resistance and tolerance to a coccidian challenge. 288 chickens of fast (F) or slow (S) growing lines were inoculated with 0 (control), 2500 (low-dose), or 7000 (high-dose) sporulated E. maxima oocysts at 13 days of age in two consecutive rounds. Gain and Intake were measured daily and their values relative to BW at the point of infection were calculated over the pre-patent (days 1-4 post-infection), acute (d5-8 pi), and recovery (d9-12 pi) phases of infection to assess the impact of infection. Levels of plasma carotenoids, vitamins E and A, long bone mineralisation, caecal microbiota diversity indices, and histological measurements were assessed at the acute (d6 pi) and recovery stage (d13 pi). In addition, we measured the levels of nitric oxide metabolites and the number of parasite genome copies in the jejunumat d6pi. In absolute terms F birds grew 1.42 times faster than S birds when not infected. Infection significantly reduced relative daily gain and intake (P < 0.001), with the effects being most pronounced during the acute phase (P < 0.001). Levels of all metabolites were significantly decreased, apart from NO which increased (P < 0.001) in response to infection on d6pi, and were accompanied by changes in histomorphometric features and the presence of E. maxima genome copies in infected birds, which persisted to d13pi. Furthermore, infection reduced tibia and femur mineralisation, which also persisted to d13pi. Reductions in measured variables were mostly independent of dose size, as was the level of parasite replication. The impact of infection was similar for S and F-line birds for all measured parameters, and there were no significant interactions between line x dose size on any of these parameters. In conclusion, our results suggest that line differences in productive performance do not influence host responses to coccidiosis when offered nutrient adequate diets.

Zataria multiflora essential oil reduces replication rate of avian influenza virus (H9N2 subtype) in challenged broiler chicks.

1. The effect of Zataria multiflora essential oil on replication rate of the H9N2 virus in target organs was determined by real-time PCR. One-day-old broiler chicks were randomly divided into six groups and were challenged with H9N2 influenza. Two groups received either 20 or 40 µl/kg body weight/day Zataria multiflora essential oils (ZM) seven days before the challenge while two other groups received the essential oil at the same dosage but after H9N2 challenge. One group received 4 mg/kg body weight/day of the anti-viral compound amantadine after challenge and the last group received no treatment and served as the control. 2. Groups that received the ZM, before or after H9N2 challenge, and the amantadine treated group showed reduced viral replication in the respiratory and gastrointestinal tracts compared to the control. Supplementation with ZM improved weight gain and FCR in broilers in comparison with the control. 3. The results showed that ZM had a positive effect on reducing viral replication in both the intestine and trachea of H9N2 influenza infected broiler chickens, that led to milder clinical symptoms and better performance.

Abnormal histopathology, fat percent and hepatic apolipoprotein A I and apolipoprotein B100 mRNA expression in fatty liver hemorrhagic syndrome and their improvement by soybean lecithin.

To investigate the etiopathogenesis of fatty liver hemorrhagic syndrome (FLHS) and the protective effects of soybean lecithin against FLHS in laying hens, 135 healthy 300-day-old Hyline laying hens were randomly divided into groups: control (group 1), diseased (group 2), and protected (group 3). Each group contained 45 layers with 3 replicates. The birds in these 3 groups were fed a control diet, a high-energy/low-protein (HELP) diet or the HELP diet supplemented with 3% soybean lecithin instead of maize. The fat percent in the liver was calculated. Histopathological changes in the liver were determined by staining, and the mRNA expression levels of apolipoproteinA I (apoA I) and apolipoprotein B100 (apoB100) in the liver were determined by RT-PCR. The results showed that the fat percent in the liver of group 2 was much higher (P < 0.01) than that of group 1 and group 2 on d 30 and 60. The histology of the liver in group 2 on d 30 and 60 displayed various degrees of liver lesions, while the hepatocytes showed a normal structure in group 3 with mild microvesicular steatosis in the liver cell on d 30 and 60. The mRNA expression levels of apoA I and apoB100 in the livers were variable throughout the experiment. The expression level of apoA I in group 2 significantly decreased on d 60 (P < 0.05); the expression level of apoB100 slightly increased on d 30 in group 2, while it sharply decreased on d 60. Compared to group 1, the expression level of apoB100 showed no significant difference in group 3 (P < 0.05). This study indicated that FLHS induced pathological changes and abnormal expression of apoA I and apoB100 in the livers of laying hens and that soybean lecithin alleviated these abnormal changes.

Effects of the Oral Administration of K2Cr2O7 and Na2SeO3 on Ca, Mg, Mn, Fe, Cu, and Zn Contents in the Heart, Liver, Spleen, and Kidney of Chickens.

This study aimed to investigate the effects of selenium on the ion profiles in the heart, liver, spleen, and kidney through the oral administration of hexavalent chromium. Approximately 22.14 mg/kg b.w. K2Cr2O7 was added to water to establish a chronic poisoning model. Different selenium levels (0.00, 0.31, 0.63, 1.25, 2.50, and 5.00 mg Na2SeO3/kg b.w.) around the safe dose were administered to the experimental group model. Ca, Mg, Mn, Fe, Cu, and Zn were detected in the organs through flame atomic absorption spectrometry after these organs were exposed to K2Cr2O7 and Na2SeO3 for 14, 28, and 42 days. Results showed that these elements exhibited various changes. Ca contents declined in the heart, liver, and spleen. Ca contents also decreased on the 28th day and increased on the 42nd day in the kidney. Mn contents declined in the heart and spleen but increased in the kidney. Mn contents also decreased on the 28th day and increased on the 42nd day in the liver. Cu contents declined in the heart and spleen. Cu contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Zn contents declined in the heart and spleen. Zn contents increased on the 28th day and decreased on the 42nd day in the liver and kidney. Fe contents decreased in the heart and liver. Fe contents increased on the 28th day and decreased on the 42nd day in the spleen and kidney. Mg contents did not significantly change in these organs. Appropriate selenium contents enhanced Mn and Zn contents, which were declined by chromium. Conversely, appropriate selenium contents reduced Ca, Fe, and Cu contents, which were increased by chromium. In conclusion, the exposure of chickens to K2Cr2O7 induced changes in different trace elements, and Na2SeO3 supplementation could alleviate this condition.

Blood biochemistry, thyroid hormones, and performance in broilers with ascites caused by caffeine.

Previously, we demonstrated that caffeine, a natural alkaloid, stimulates increased incidences of pulmonary hypertension syndrome (ascites) in broilers. The present study was designed to evaluate the ergogenic effects of caffeine on broiler performance and blood parameters. One-hundred-and-ninety-two Ross 308 male broiler chicks were randomly assigned at one d of age to 16 pens with 4 treatment groups. On d 3, the drinking water was supplemented with caffeine at levels of zero, 12.5, 25, and 50 mg/kg BW/day. Caffeine supplementation linearly improved (P < 0.01) body weight gain (BWG) and the feed conversion ratio (FCR); however, feed intake was not affected by caffeine (P > 0.05). On d 28, increasing caffeine supplementation caused linear reductions in plasma albumin, total protein, globulin, and triglyceride concentrations, and caffeine supplementation increased plasma uric acid concentrations (P < 0.05). On d 42, caffeine did not consistently affect plasma albumin, globulin, triglyceride, total protein, uric acid, or urea concentrations (P > 0.05), whereas plasma glucose concentrations increased linearly with increasing caffeine levels (P < 0.05). Plasma T4 concentrations were not affected by caffeine (P > 0.05), but plasma T3 concentrations were reduced by caffeine supplementation on d 28 and 42 (P < 0.05). The T3:T4 ratios also were reduced by caffeine supplementation on d 42. Skin temperature was not influenced by caffeine supplementation (P > 0.05). There was a negative correlation between thyroid hormone concentrations and BW on d 42 (P < 0.05). It can be concluded that caffeine supplementation at the levels of 12.5 to 25 mg/kg BW/day increased BWG, decreased FCR and T3, and significantly altered blood biochemistry parameters.

Investigation of the effect of coccidial vaccine challenge on apparent and standardized ileal amino acid digestibility in grower and finisher broilers and its evaluation in 21-day-old broilers.

The effect of coccidial vaccine challenge (CVC, Coccivac(®)B; challenged, CHA; or unchallenged, NCH) on ileal endogenous amino acid (IEAA) losses and standardized ileal AA digestibility (SIAAD) in 21- and 42-day-old broilers fed a corn-soybean meal-dried distillers' grains with solubles-poultry by-product meal-based diet (Expt. 1) and the effect of supplemental AA in ameliorating the effect of CVC (Expt. 2) were evaluated. Expt. 1 was designed as a 2 (d 21 or 42) x 2 (NCH or CHA) factorial arrangement of treatments with 8 replicates in a complete randomized design. The CVC birds were gavaged with 12 x coccidial vaccine on d 15 and 36 and were sampled on 6 d post challenge. SIAAD was determined by correcting apparent ileal AA digestibility for IEAA losses. Feed intake (FI) and BW gain were higher (P ≤ 0.05) in 21-day-old NCH birds compared to the 21-day-old CHA birds while 42-day-old birds had higher FI and BW gain than 21-day-old NCH and CHA birds. Ileal endogenous nitrogen loss was higher (P ≤ 0.05) in 42-day-old CHA birds compared to 42-day-old NCH birds. Apparent ileal AA digestibility in 21-day-old CHA birds was lower (P ≤ 0.05) than for 21-day-old NCH and 42-day-old NCH and CHA birds. SIAAD in 21-day-old CHA birds was lower (indispensable AA = 15.2 and dispensable AA = 17.8%-unit; P ≤ 0.05) than for 21-day-old NCH and 42-day-old NCH and CHA birds. Apparent ileal digestibility and total tract utilization of DM, N, and energy were not different between d 21 NCH and d 42 NCH and CHA birds but higher (P ≤ 0.05) than for d 21 CHA birds. Supplemental AA restored feed efficiency, but not BW gain, to that of the positive control (0.715 vs. 0.737). Results from Expt.1 showed that CVC significantly influenced ileal AA digestibility in 21- but not in 42-day-old birds. Expt. 2 showed that consideration of SIAAD in feed formulation may benefit feed efficiency.

Carcass and meat quality traits of chickens fed diets concurrently supplemented with vitamins C and E under constant heat stress.

The objective of this study was to determine if a diet supplemented simultaneously with vitamins C and E would alleviate the negative effects of heat stress, applied between 28 and 42 days of age, on performance, carcass and meat quality traits of broiler chickens. A total of 384 male broiler chickens were assigned to a completely randomized design, with a 2×3 factorial arrangement (diet with or without vitamin supplementation and two ambient temperatures plus a pair-feeding group) and 16 replicates. Chickens were kept in thermoneutral conditions up to 28 days of age. They were then housed in groups of four per cage, in three environmentally controlled chambers: two thermoneutral (22.5 and 22.6°C) and one for heat stress (32°C). Half the chickens were fed a diet supplemented with vitamins C (257 to 288 mg/kg) and E (93 to 109 mg/kg). In the thermoneutral chambers, half of the chickens were pair-fed to heat stressed chickens, receiving each day the average feed intake recorded in the heat stress chamber in the previous day. Meat physical quality analyses were performed on the pectoralis major muscle. No ambient temperature×diet supplementation interaction effects were detected on performance, carcass, or meat quality traits. The supplemented diet resulted in lower growth performance, attributed either to a carry-over effect of the lower initial BW, or to a possible catabolic effect of vitamins C and E when supplemented simultaneously at high levels. Heat stress reduced slaughter and carcass weights, average daily gain and feed intake, and increased feed conversion. Growth performance of pair-fed chickens was similar to that of heat stressed chickens. Exposure to heat stress increased carcass and abdominal fat percentages, but reduced breast, liver and heart percentages. Pair-fed chickens showed the lowest fat percentage and their breast percentage was similar to controls. Heat stress increased meat pH and negatively affected meat color and cooking loss. In pair-fed chickens, meat color was similar to the heat stressed group. Shear force was not influenced by heat stress, but pair-fed chickens showed the tenderest meat. In conclusion, reduction in growth performance and negative changes in meat color in heat stressed chickens were attributed to depression in feed intake, whereas negative changes in body composition, higher meat pH and cooking loss were credited to high ambient temperature per se. Diet supplementation with vitamins C and E as antioxidants did not mitigate any of these negative effects.

Effect of zinc on growth performance, gut morphometry, and cecal microbial community in broilers challenged with Salmonella enterica serovar typhimurium.

To evaluate the effects of supplemental zinc on growth performance, gut morphometry, and the cecal microbial community in broilers challenged with Salmonella typhimurium, 180, 1-day-old male Cobb 500 broiler chicks were randomly assigned to 3 treatments with ten replicates for a 42 day experiment. The 3 treatments were: unchallenged, S. typhimurium-challenged, and S. typhimurium-challenged with 120 mg/kg of zinc supplementation in the diet. Salmonella infection caused a reduction in body-weight gain and feed intake, disrupted the intestinal structure by decreasing the villus-height/crypt-depth ratio of the ileum and increasing the apoptotic index of ileal epithelial cells. Moreover, the cecal microbial community was altered by Salmonella infection, as demonstrated by a reduced number of Lactobacillus and total bacteria. Dietary zinc supplementation improved growth performance by increasing the body-weight gain and feed intake in the challenged broilers. In addition, zinc repaired intestinal injury by reducing the apoptotic index of ileal epithelial cells, enhancing villus height and the villus-height/crypt-depth ratio of the ileum, and the proliferation index of ileal epithelial cells. Finally, zinc regulated the cecal microbial community by increasing the number of total bacteria and beneficial Lactobacillus bacteria, and reducing the number of Salmonella. The results indicated that dietary zinc supplementation improved growth performance, intestinal morphology, and intestinal microbiota in S. typhimurium-challenged broilers.

Dietary calcium, phosphorus, and phytase effects on bird performance, intestinal morphology, mineral digestibility, and bone ash during a natural necrotic enteritis episode.

The objective of this study was to evaluate the effects of dietary Ca, P, and phytase on performance, intestinal morphology, bone ash, and Ca and P digestibility during a necrotic enteritis (NE) outbreak. The 35-d trial was designed as a 2 × 2 × 2 factorial, which included 2 Ca levels (0.6 and 0.9%), 2 P levels (0.3 and 0.45%), and 2 levels of phytase [0 and 1,000 phytase units (FTU)/kg]. Birds were placed on litter from a previous flock that exhibited clinical signs of NE. Birds and feed were weighed on d 12, 19, and 35, and BW gain, feed intake, and feed conversion were calculated. Mortality was recorded daily, and gastrointestinal pH was measured. Tibias and ileal digesta were also collected. Birds began exhibiting clinical signs of NE on d 9, and NE-associated mortality persisted until d 26. Dietary Ca supplemented at 0.9% or inclusion of 1,000 FTU/kg of phytase significantly increased mortality compared with 0.6% Ca or 0 FTU/kg of phytase, respectively. From d 0 to 12, birds fed 0.9% Ca and 0.45% available P with phytase had greater BW gain compared with birds fed 0.6% Ca, 0.45% available P, and phytase. From d 0 to 19, birds fed diets with 0.9% Ca and 0.3% available P had decreased feed intake and improved feed conversion compared with birds fed 0.9% Ca and 0.45% available P. Calcium at 0.9% increased gizzard (d 19) and jejunum (d 12) pH. Phytase supplementation significantly increased Ca digestibility regardless of Ca and P levels of the diets. In addition, diets containing 0.6% Ca and 1,000 FTU/kg of phytase resulted in a significant increase in P digestibility. The results suggest that dietary Ca level may influence NE-associated mortality. In addition, bird performance was affected by interactions of Ca, P, and phytase during the exposure to Clostridium perfringens and the subsequent NE outbreak. Results showed improvements in bird performance when birds were fed 0.6% Ca and 0.3% P in diets supplemented with phytase, which was likely consequent to the influence of Ca in NE pathogenesis.

Performance, egg quality traits, and serum metabolite concentrations of laying hens affected by dietary supplemental chromium picolinate and vitamin C under a heat-stress condition.

A 3 × 2 factorial experiment consisting three levels (0, 200, and 400 µg/kg) of chromium (chromium picolinate) and two levels (0 and 250 mg/kg) of vitamin C was employed to evaluate the effects of these dietary supplements on performance, egg quality traits, and serum biochemical parameters of heat-stressed laying hens (Lohmann LSL-Lite) from 66 to 74 weeks of age. Feed intake increased when birds were given either 400 µg/kg chromium or 250 mg/kg vitamin C (P < 0.05), but the birds that received both chromium and vitamin C consumed feed similar to those that received only chromium. Dietary treatments had no effect on egg production, egg mass, egg volume, feed conversion ratio, and body mass (P > 0.05). The birds that fed on diet with chromium or vitamin C produced eggs with higher shell mass and thickness compared to the control. Both eggshell mass and thickness decreased when vitamin C and chromium were supplemented simultaneously, and birds given the diet supplemented with 400 µg/kg chromium and 250 mg/kg vitamin C had eggshell mass and thickness similar to those of the control group. The serum concentration of chromium increased due to increasing level of dietary chromium (P < 0.05). The birds that received diet with chromium and vitamin C had higher serum concentrations of chromium compared to those that received only chromium (P < 0.05). Similarly, the hens that received chromium and vitamin C had higher serum concentrations of calcium and phosphorus compared to the hens fed with other treatments (P < 0.05). The birds given with supplemental chromium exhibited lower serum glucose, total cholesterol, and triglycerides concentrations but higher serum albumin and total protein concentrations compared to the other groups (P < 0.05).

LPS-induced inflammation in the chicken is associated with CCAAT/enhancer binding protein beta-mediated fat mass and obesity associated gene down-regulation in the liver but not hypothalamus.

BACKGROUND: The fat mass and obesity associated gene (FTO) is widely investigated in humans regarding its important roles in obesity and type 2 diabetes. Studies in mammals demonstrate that FTO is also associated with inflammation markers. However, the association of FTO with inflammation in chickens remains unclear. In this study, male chickens on day 28 posthatching were injected intraperitoneally with lipopolysaccharide (LPS) or saline to investigate whether the FTO gene is involved in LPS-induced inflammation. RESULTS: We detected significant down-regulation of FTO mRNA in the liver (P < 0.01), but not in the hypothalamus, 2 and 24 h after LPS challenge. Toll-like receptor (TLR) 2 (P < 0.01) and TLR4 (P < 0.01) followed the same pattern as FTO, being suppressed significantly in liver but not in hypothalamus. IL-1ß was dramatically up-regulated (P < 0.01) in both liver and hypothalamus 2 h after LPS challenge, while activation of IL-6 was observed in the liver (P < 0.01), but not in hypothalamus. The 5'-flanking sequence of the chicken FTO gene contains nine predicted binding sites for CCAAT/enhancer binding protein beta (C/EBP beta) and one for signal transducer and activator of transcription 3 (STAT3). Significant elevation of C/EBP beta was detected in the liver (P < 0.01), but not in the hypothalamus, 2 h after LPS challenge. Lipopolysaccharide challenge increased the C/EBP beta binding to FTO promoter in the liver (P < 0.01 for fragment 1, P < 0.05 for fragment 2), although the protein content of C/EBP beta was not altered. Moreover, injection of LPS resulted in enhanced phosphorylation of liver STAT3, a downstream transcription factor in IL-6 signaling. Although phosphorylated STAT3 was not detected to directly bind to FTO promoter, it was found to interact with C/EBP beta. CONCLUSION: Our results reveal that FTO expression in liver, but not in hypothalamus, is affected by the i.p. injection of LPS, which may be mediated through tissue-specific FTO transcriptional regulation by C/EBP beta and STAT3 interaction.

Proteolytic activity alterations resulting from force-feeding in Muscovy and Pekin ducks.

We investigated liver protease activity in force-fed and non-force-fed ducks using zymography gels to better understand mechanisms underlying liver steatosis in palmipeds. Male Muscovy and Pekin ducks were slaughtered before and after a short period (13 d) while they were conventionally fed or force fed. The force-fed regimen contained a high level of carbohydrates and was delivered in large doses. Main hepatic proteases (matrix metalloprotease-2, calpains, and cathepsins) were extracted from raw liver and specifically activated within electrophoretic gels. Both force-fed Muscovy and Pekin ducks presented higher liver weights and BW associated with lower matrix metalloprotease-2 and m-calpain hepatic activities. On the other hand, hepatic cathepsin activity was not affected by force feeding. It was concluded that Muscovy and Pekin duck hepatic proteases are affected similarly by the force feeding. Thus, this cannot explain differences observed between Muscovy and Pekin ducks regarding their ability to develop hepatic steatosis generally reported in literature.