Jianmin Yuan

Growth performance and immune responses in chickens after challenge with lipopolysaccharide and modulation by dietary different oils

The study was conducted to investigate the effects of different oils on growth performance and immune responses of chickens after challenge with lipopolysaccharide (LPS). A total of 288 chickens were assigned in a 2 × 2 factorial design. Factors were dietary fat type (4.5% maize oil or 4.5% fish oil) and immunological challenge (LPS or saline). At 20 days and 27 days of age, chickens were injected intraperitoneally with either 1 mg/kg body weight of LPS or sterile saline. LPS decreased feed intake from 21 days to 28 days of age and body-weight gain from 21 days to 42 days of age. Fish oil improved feed-conversion efficiency of chickens after LPS challenge for the first time. Fish oil supplementation decreased lymphocyte proliferation (21 days: P < 0.0001; 28 days: P < 0.0001) and the ratio of CD3+CD4+/CD3+CD8+ (21 days: P = 0.0479; 28 days: P = 0.0009) after LPS challenge. LPS challenge increased the levels of interleukin-1 (IL-1) (21 days: P < 0.0001; 28 days: P = 0.0030), IL-6 (21 days: P < 0.0001; 28 days: P = 0.0001) and tumor necrosis factor-α (TNF-α) (21 days: P = 0.0008; 28 days: P = 0.0018). And fish oil alleviated the elevations in the production of IL-6 (21 days: P = 0.0359; 28 days: P = 0.0302) and TNF-α (21 days: P = 0.0055; 28 days: P = 0.0391) induced by the LPS challenge. Fish oil alleviated the mRNA abundance elevation of nuclear factor kappa B (NFκB) (21 days: P = 0.0079; 28 days: P = 0.0017) after LPS challenge. These results showed that fish oil acts as an anti-inflammatory agent, which may be associated with down-regulation of the activated immune system. The results of pro-inflammatory cytokines and mRNA abundance results suggested that fish oil might alleviate the elevation of IL-6 and TNF-α induced by LPS through down-regulating NFκB expression.

Dietary conjugated linoleic acid improves antioxidant capacity in broiler chicks.

1. The influence of dietary conjugated linoleic acid (CLA) on the antioxidant status in the absence or presence of endotoxin exposure was studied with male broiler chicks. 2. In experiment 1, a total of 240 1-d-old broilers were allotted into 4 dietary groups (0, 2·5, 5·0 or 10·0 g pure CLA/kg) to study the influence of CLA on growth performance and antioxidant defence systems. The results showed that growth performance was not altered by 42 d of CLA consumption. Increased total superoxide dismutase (TSOD) activities in liver, serum and muscle were observed in chicks given 10·0 g CLA/kg diet. Dietary CLA at 10·0 g/kg also markedly elevated liver catalase (CAT) activity. Malondialdehyde (MDA), a marker of lipid peroxidation, decreased in liver, serum and muscle in chicks given 5·0 and 10·0 g CLA/kg diet. 3. In experiment 2, a total of 120 1-d-old broilers were fed on a control diet (without CLA) or 10·0 g CLA/kg diet. Half of the birds fed on each diet were injected intraperitoneally with 0·25 mg/kg body weight of Salmonella enteritidis lipopolysaccharide (LPS) at 16, 18 and 20 d of age. Decreased glutathione peroxidase (GSH-Px), TSOD activity and increased ceruloplasmin and MDA concentrations were seen in the challenged chicks. Dietary CLA prevented the loss of body weight gain and feed conversion ratio of chicks followed repeated endotoxin exposure. CLA partially inhibited the increase of serum ceruloplasmin and MDA at 17 and 21 d of age and notably suppressed the decrease of serum TSOD activity at 21 d of age. 4. These results suggested that dietary CLA enhances the activity of antioxidant enzymes including TSOD and CAT. Supplementation of CLA has been shown to ameliorate the antioxidant balance and performance of chicks during oxidative stress.

Zinc prevents Salmonella enterica serovar Typhimurium-induced loss of intestinal mucosal barrier function in broiler chickens

The study was carried out to evaluate the beneficial effects of supplemental zinc (Zn) on the intestinal mucosal barrier function in Salmonella enterica serovar Typhimurium-challenged broiler chickens in a 42-day experiment. A total of 336 1-day-old male Arbor Acres broiler chicks were assigned to eight treatment groups. A 4×2 factorial arrangement of treatments was used in a completely randomized experimental design to study the effects of levels of supplemental Zn (0, 40, 80 and 120 mg/kg diet), pathogen challenge (with or without S. Typhimurium challenge), and their interactions. S. Typhimurium infection caused reduction of growth performance (P<0.05) and intestinal injury, as determined by reduced (P<0.05) villus height/crypt depth ratio and sucrase activity in the ileum, increased (P<0.05) plasma endotoxin levels, and reduced (P<0.05) claudin-1, occludin and mucin-2 mRNA expression in the ileum at day 21. Zn pre-treatment tended to improve body weight gain (P=0.072) in the starter period, to increase the activity of ileal sucrase (P=0.077), to reduce plasma endotoxin levels (P=0.080), and to significantly increase (P<0.05) the villus height/crypt depth ratio and mRNA levels of occludin and claudin-1 in the ileum at day 21. The results indicated that dietary Zn supplementation appeared to alleviate the loss of intestinal mucosal barrier function induced by S. Typhimurium challenge and the partial mechanism might be related to the increased expression of occludin and claudin-1 in broiler chickens.

Enhancement of Peripheral Blood CD8+ T Cells and Classical Swine Fever Antibodies by Dietary β-1,3/1,6-glucan Supplementation in Weaned Piglets

The experiment was conducted to evaluate the effect of dietary supplementation with 0, 50, 100 and 200 mg/kg of beta-1,3/1,6-glucan extracted from Saccharomyces cerevisiae on cellular immune responses and classical swine fever virus (CSFV) antibody production of weaned piglets. Thirty-two (Landrace x Large White; 26 days old; 7.05+/-0.25 kg body weight) castrated male piglets were randomly allocated to four treatments, eight pigs per treatment. All piglets were vaccinated with live-attenuated Chinese strain cell vaccines at 26 days of age. The results showed that dietary supplementation with beta-1,3/1,6-glucan could significantly (P<0.01) enhance peripheral blood lymphocyte proliferation activity in weaned piglets after 14 days administration, whereas no significant effect (P>0.05) was observed on day 28. Dietary beta-1,3/1,6-glucan supplementation could significantly enhance CSFV antibody blocking rate (P<0.05) on days 14 and 21 after inoculation. Although dietary beta-1,3/1,6-glucan supplementation did not significantly influence (P>0.05) lymphocyte subgroups on day 14, high levels of beta-1,3/1,6-glucan (100 and 200 mg/kg) increased the percentage of cytotoxic/suppressor lymphocytes (CD8(+)) significantly (P<0.05), decreased the ratio of CD4(+)/CD8(+) significantly (P<0.05) and increased the percentage of total T lymphocytes (CD3(+)) on day 28. These results suggest that beta-1,3/1,6-glucan may have a beneficial effect on the immune system of swine, and dietary beta-1,3/1,6-glucan supplementation had a transient impact on lymphocyte proliferation activity. The CSFV antibody blocking rate and the percentage of peripheral blood CD8(+) T cells could be enhanced by continuous beta-1,3/1,6-glucan supplementation. These findings support the potential application of beta-1,3/1,6-glucan as a prophylactic agent in increasing animal immune functions and controlling CSF disease.

Effect of dietary nonphytate phosphorus on laying performance and small intestinal epithelial phosphate transporter expression in Dwarf pink-shell laying hens

This study examined the effects of various levels of dietary nonphytate phosphorus on laying performance and the expression patterns of phosphorus metabolism related genes in Dwarf pink-shell laying hens. A total of 405 28-week-old Dwarf pink-shell laying hens were fed the same corn-soybean basal meals but containing 0.20%, 0.25%, 0.30%, 0.35% or 0.40% nonphytate phosphorus. The results showed that feed intake, egg production, and average egg weights were quadratically correlated with dietary nonphytate phosphorus content (Pu2009<u20090.05), and the highest egg production, feed intake and average egg weights were achieved when dietary nonphytate phosphorus was at 0.3% (Pu2009<u20090.05). mRNA expression of intestinal sodium phosphorus co-transporter linearly decreased when dietary nonphytate phosphorus increased. mRNA and protein expression of intestinal calbindin and vitamin D receptor correlated quadratically with dietary nonphytate phosphorus, and the highest expression was found when dietary available phosphorus was at 0.25% to 0.3%. In conclusion, the ideal phosphorus requirement for Dwarf pink-shell layer hens is estimated to be 0.3% in a corn-soybean diet. With this level of phosphorus supplementation, calbindin and vitamin D receptor reached their highest expression.

Dietary conjugated linoleic acid enhances spleen PPAR-γ mRNA expression in broiler chicks

1. The anti-inflammatory effects of dietary conjugated linoleic acid (CLA) on broilers repeatedly challenged with lipopolysaccharide (LPS) were investigated. 2. Day-old broiler chicks were allotted into three treatment groups and fed on a control diet or diets containing 5·0 or 10·0u2009g CLA/kg diet. Six chicks from each treatment were injected with LPS (0·25u2009mg/kg body weight) at 16, 18 and 20u2009d of age. Splenic cyclooxygenase (COX) and inducible nitric oxide synthase (iNOS) activities, and prostaglandin E2 (PGE2) and nitric oxide (NO) production as well as peroxisome proliferator-activated receptor-γ (PPAR-γ) mRNA expression were measured at 21u2009d of age. 3. Chicks fed 10·0u2009g CLA/kg diet had lower COX activities and PGE2 production than the controls. Dietary CLA (10·0u2009g/kg) did not significantly diminish LPS-induced enhancement of COX-2 activity, but inhibited the subsequent increase in PGE2 production. 4. Regulation of COX-1 activity contributed to the difference in PGE2 production. 5. CLA did not markedly attenuate the increase of iNOS activity and NO production caused by LPS challenge. Chicks fed CLA had lower iNOS activity and NO production than the controls. 6. Dietary CLA activated splenic PPAR-γ mRNA expression and increased PPAR-γ mRNA expression after LPS injection. 7. These results suggest that dietary CLA has immunomodulatory effects in the spleen by restricting basal PGE2 and NO to lower levels and enhancing PPAR-γ mRNA expression. During the inflammatory response, dietary CLA did not alleviate the increase in COX-2 and iNOS activities but enhanced PPAR-γ mRNA expression.

Effects of dietary tryptophan and stocking density on the performance, meat quality, and metabolic status of broilers

BackgroundHighly automated cage-rearing systems are becoming increasingly popular in China. However, a high stocking density can cause oxidative stress and decrease broiler performance. The tryptophan (TRP) derivative 5-hydroxytryptophan (5-HT) has been shown to preserve membrane fluidity in birds suffering from oxidative stress. Therefore, this experiment was conducted to determine the effects of dietary TRP supplementation on performance, breast meat quality and oxidative stress in broilers reared in cages with a high or low stocking density.MethodsFemale Arbor Acres broilers (25-d-old, nu2009=u2009144) were randomly allocated to 1 of 4 treatments. The birds were fed a diet based on corn, soybean meal, cottonseed meal and corn gluten meal containing either 0.18 or 0.27% TRP and were housed with stocking densities of 11 or 15.4 birds/m2 in a 2u2009×u20092 factorial experiment. Broiler performance was evaluated from d 25 to 42. Eight birds from each treatment were slaughtered on d 42 and plasma and breast muscle samples were collected to measure biochemical indices.ResultsA higher stocking density tended to be associated with reduced weight gain (Pu2009<u20090.10), and significantly increased plasma glutamic-pyruvic transaminase (GPT) activity (Pu2009<u20090.001). Increased dietary TRP significantly reduced the activities of lactic dehydrogenase and GPT while increasing total cholesterol in the plasma (Pu2009<u20090.01), reducing drip loss of breast muscle (Pu2009<u20090.10) and improving feed efficiency (Pu2009<u20090.10).ConclusionsAn increase in dietary TRP, 1.5-fold higher than the standard supplementation level, can alleviate oxidative stress as well as improve welfare and feed efficiency in broilers reared in cages with a high stocking density.

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.

Effect of taurine on intestinal morphology and utilisation of soy oil in chickens

1.u2003The objective of the present study was to investigate the effect of taurine on intestinal morphology and utilisation of dietary fatty acids in chicken. One-day-old broilers chickens were fed with a maize- and soybean-based diet containing soy oil, and supplemented with taurine at either 0 or 0·5 g/kg. 2.u2003Result showed that the total bile acid in blood and lipase activity in the small intestine were elevated in 3-week-old broilers given the taurine-supplemented diet. No differences were observed for total serum bile acid and lipase activity between the groups of 6-week-old broilers. 3.u2003The development of the jejunum villus and ileum villus was inhibited, and the weight of jejunum and the relative height of intestinal mucosa were decreased in the chickens fed the taurine-supplemented diet. 4.u2003The rate of diet fatty acid utilisation was not different between the groups of 3- and 6-week-old chickens. 5.u2003Our results showed that dietary supplementation with taurine had no beneficial effect on intestinal morphology or utilisation of a soy oil diet in chickens.

Combination of Xylanase and Debranching Enzymes Specific to Wheat Arabinoxylan Improve the Growth Performance and Gut Health of Broilers

Arabinoxylan (AX) is the major antinutritional factor of wheat. This study evaluated the synergistic effects of xylanase and debranching enzymes (arabinofuranosidase [ABF] and feruloyl esterase [FAE]) on AX. During in vitro tests, the addition of ABF or FAE accelerated the hydrolysis of water-soluble AX (WE-AX) and water-insoluble AX (WU-AX) and produced more xylan oligosaccharides (XOS) than xylanase alone. XOS obtained from WE-AX stimulated greater proliferation of Lactobacillus brevis and Bacillus subtilis than did fructo-oligosaccharides (FOS) and glucose. During in vivo trials, xylanase increased the average daily growth (ADG), decreased the feed-conversion ratio (FCR), and reduced the digesta viscosity of jejunum and intestinal lesions of broilers fed a wheat-based diet on day 36. ABF or FAE additions further improved these effects. Broilers fed a combination of xylanase, ABF, and FAE exhibited the best growth. In conclusion, the synergistic effects among xylanase, ABF, and FAE increased AX degradation, which improve the growth performance and gut health of broilers.