Dietary protocatechuic acid ameliorates ileal mucosal barrier injury and inflammatory response and improves intestinal microbiota composition in Yellow chickens challenged with Salmonella typhimurium.

Salmonella typhimurium (ST) is a common foodborne pathogen that severely affects the health of humans and livestock. Protocatechuic acid (PCA) has been shown to possess anti-inflammatory and anti-bacterial functions. Chickens were used to investigate the effect of PCA on the gut health infected with ST. A total of one hundred eighty, 1-d-old birds were randomly allocated into 3 treatments, each with 6 replicates per treatment and 10 chicks per replicate. Broiler chicks in the control and ST treatment were fed a basal diet, and birds in the PCA+ST treatment received the basal diet with 600 mg/kg PCA. On d 14 and 16 of the trial, broilers in ST and PCA+ST treatments received an oral dose of ST, while broilers in CON received an equal amount of PBS. The data were analyzed by the one-way ANOVA. Dietary PCA increased (P < 0.05) final body weight, average daily gain, and feed to gain ratio in ST-challenged Yellow broilers. Protocatechuic acid significantly alleviated ST-induced intestinal mucosal injury reflected in the decreased (P < 0.05) plasma activity of diamine oxidase and ileal apoptosis, with increased (P < 0.05) ileal villus height and villus height/crypt depth. Protocatechuic acid treatment significantly decreased (P < 0.05) ST-induced proinflammatory cytokine (Interleukin-1ß, Interleukin-6, Tumor necrosis factor-α, and Interferon-ß) content in ileum. Meanwhile, PCA treatment significantly increased (P < 0.05) the transcript abundances of claudin 1 (CLDN1), zonula occludens-1 (ZO-1), and mucin 2 (MUC2) in ileum, all related to the intestinal barrier in ST-challenged Yellow broilers. Additionally, PCA also increased (P < 0.05) the diversity and richness of the cecal microflora as reflected by reduced (P < 0.05) abundance of Bacteroidota, Proteobacteria and Escherichia-Shigella, and increased (P < 0.05) abundance of Firmicutes and Lactobacillus in ST-challenged Yellow broilers. These findings indicate that PCA relieves ST-induced loss weight, intestinal barrier injury, inflammatory response, and improves intestinal microbiota composition in Yellow broilers.

Curcumin alleviates LPS-induced intestinal homeostatic imbalance through reshaping gut microbiota structure and regulating group 3 innate lymphoid cells in chickens.

Gastrointestinal dysfunction is associated with a disturbance of immune homeostasis, changes in the intestinal microbiome, alteration of the composition of the bile acid pool, and dynamic imbalance of group 3 innate lymphoid cells (ILC3s). Curcumin (CUR), a polyphenolic compound isolated from turmeric, has been known to attenuate intestinal inflammation in potential therapies for gastrointestinal diseases. It was hypothesized that CUR could target the gut microbiome to modulate bile acid (BA) metabolism and the function of ILC3s in ameliorating lipopolysaccharide (LPS)-induced imbalance of intestinal homeostasis in chickens. Seven hundred and twenty 1-day-old crossbred chickens were randomly divided into four treatments, namely CON_saline (basal diet + saline control), CUR_saline (basal diet + 300 mg kg-1 curcumin + saline), CON_LPS (basal diet + LPS), and CUR_LPS (basal diet + 300 mg kg-1 curcumin + LPS), each consisting of 6 replicates of 30 birds. On days 14, 17, and 21, the chickens in the CON_LPS and CUR_LPS treatments were intraperitoneally injected with LPS at 0.5 mg per kg BW. Dietary CUR supplementation significantly decreased LPS-induced suppression of growth performance and injury to the intestinal tight junctions and decreased the vulnerability to LPS-induced acute inflammatory response by inhibiting pro-inflammatory (interleukin-1ß and tumor necrosis factor-α) cytokines. CUR reshaped the cecal microbial community and BA metabolism, contributing to regulation of the intestinal mucosal immunity by promoting the anti-inflammatory (interleukin 10, IL-10) cytokines and enhancing the concentrations of primary and secondary BA metabolites (chenodexycholic acid, lithocholic acid). LPS decreased farnesoid X receptor (FXR) and G protein-coupled receptor class C group 5 member A synthesis, which was reversed by CUR administration, along with an increase in interleukin 22 (IL-22) production from ILC3s. Dietary supplementation of CUR increased the prevalence of Butyricicoccus and Enterococcus and enhanced the tricarboxylic acid cycle of intestinal epithelial cells. In addition, curcumin supplementation significantly increased sirtuin 1 and sirtuin 5 transcription and protein expression, which contributes to regulating mitochondrial metabolic and oxidative stress responses to alleviate LPS-induced enteritis. Our findings demonstrated that curcumin played a pivotal role in regulating the structure of the intestinal microbiome for health promotion and the treatment of intestinal dysbiosis. The beneficial effects of CUR may be attributed to the modulation of the BA-FXR pathway and inhibition of inflammation that induces IL-22 secretion by ILC3s in the intestinal lamina propria.

Dietary fiber modulates abdominal fat deposition associated with cecal microbiota and metabolites in yellow chickens.

Excessive deposition of abdominal fat is a public concern in the yellow chicken industry related to human nutrition. The common practice of nutritionists is to increase the fiber content in feed to control abdominal fat deposition of chickens. Corncob meal (CCM) is the cheapest ingredient widely used in animal diets. The possible effects of CCM on chicken abdominal fat deposition and the possible mechanism involving cecal microbiota remain unknown. The objectives of this study were to investigate the effects of CCM in modulating abdominal fat deposition and the role of the cecal microbiota and their metabolites. A total of 200 ninety-day-old Huxu female chickens were divided into 2 dietary treatments, each with 10 replicates of 10 birds, and were fed two finisher diets, from 90 to 135 d. The diets were a typical corn-soybean control diet (CON) and that diet with CCM partially replacing corn and corn gluten meal. Results showed that the CCM diet markedly decreased live weight and abdominal fat percentage (P < 0.05); chickens fed the CCM diet exhibited lower (P < 0.01) expression in abdominal fat of fatty acid binding protein 4 (FABP4), stearoyl-CoA desaturase (SCD), fatty acid synthase (FAS), and peroxisome proliferator-activated receptor γ (PPARγ) but higher (P < 0.05) expression of estrogen receptor alpha (ESR1). The CCM increased the abundance of Akkermansia (P < 0.05) and markedly reduced the relative cecal abundance of Phascolarctobacterium (P < 0.01), Rikenellaceae (P < 0.05), and Faecalibacterium (P < 0.01). The metabolomic and biochemical analyses demonstrated that the CCM diet increased (P < 0.05) the concentrations of butyrate in cecal contents. The majority of the metabolites in cecal digesta with differences in abundance were organic acids. The CCM diet increased (P < 0.05) contents of (R)-5-diphosphomevalote, pantothenic acid, 2-epi-5-epi-valiolone 7-phosphate, D-ribose 5-diphosphate, arbutin 6-phosphate, D-ribitol 5-phosphate, undecanoic acid, nicotinic acid, 4-methyl-2-oxovaleric acid, while decreasing (P < 0.05) those of oleic acid, glutaric acid, adipic acid, suberic acid, and L-fuculose 1-phosphate. In conclusion, these findings demonstrated that the dietary CCM treatment significantly decreased abdominal fat and altered the cecal microbiota and metabolite profiles of the yellow chickens.

Effects of dietary iron on reproductive performance of Chinese Yellow broiler breeder hens during the egg-laying period.

The objective of this study was to investigate the effects of dietary iron (Fe) on reproductive performance of Chinese Yellow broiler breeder hens during the egg-laying period. A total of 480, 55-wk-old hens were balanced for laying rate and then randomly allotted into 5 groups, each with 6 replicates (8 cages for each replicate with 2 birds per cage). The trial was for 10 wk. Birds were fed diet with 44, 58, 72, 86, or 100 mg/kg Fe contained feed. Laying performance, biochemical indices and reproductive hormones in plasma, egg quality, ovarian and oviductal variables, tibial breaking strength, and hatching performance were determined. The key performance variables hematocrit, hatchability of live embryos, and tibial breaking strength were selected for analysis by quadratic polynomial (QP) and broken-line (BL) regressions to better determine optimal dietary Fe level. Qualified egg (excluding those with double-yolk, soft-shell, cracked, very small malformed, etc.) rate tended to decrease with the lowest and highest dietary Fe levels. Hematocrit was affected (P = 0.003) by dietary Fe, along with linear (P = 0.017) and quadratic (P = 0.002) effect. There was a significant effect (P = 0.034) of dietary Fe level on tibial breaking strength of breeder hens with a quadratic (P = 0.044) effect. Breeder hens fed inadequate (44 mg/kg diet) or excess (100 mg/kg) Fe both had lower (P < 0.05) tibial breaking strength compared to that of hens fed 86 mg/kg Fe. Hatchability of live embryos was affected (P = 0.004) by diet; with both linear (P = 0.014) and quadratic (P = 0.001) effects. Maximal hatching of live embryos occurred with diets of breeder hens containing 72 mg/kg Fe. From the QP and BL models fitted to hematocrit, tibial breaking strength, and hatchability variables, the optimal dietary Fe level for Chinese Yellow broiler breeder hens in the laying period was 70-90 mg/kg. The daily Fe fed (allowance) was about 8-11 mg.

Effects of maternal and dietary vitamin A on growth performance, meat quality, antioxidant status, and immune function of offspring broilers.

The aim of this study was to evaluate the effects of maternal and dietary vitamin A (VA) level on growth performance, meat quality, antioxidant status, and immune function of offspring broilers. Chinese yellow-feathered breeder hens were fed a basal diet supplemented with 0, 5,400, 10,800, and 21,600 IU/kg VA for 8 wk, with 6 replicates of 22 hens per replicate. Then the offspring hatched from each of the 4 maternal groups were fed a basal diet supplemented with 0 or 5,000 IU/kg VA for 63 D. Overall, there were 8 treatment combinations, each with 6 replicate pens of 20 birds. Results showed that (1) providing VA in offspring diets increased final body weight (FW), average daily gain, and average daily feed intake but reduced feed-to-gain ratio and mortality of offspring broilers (P < 0.05), whereas maternal provision of VA did not significantly affect the growth performance and mortality of offspring broilers. Maternal or offspring VA did not affect proportion of breast or thigh muscle (P > 0.05). (2) Maternal feeding with 21,600 IU/kg VA increased (P < 0.05) pH 24 h postmortem of breast muscle, compared with those without maternal supplication of VA. Dietary provision of 5,000 IU/kg VA in the posthatching diet decreased (P < 0.05) drip loss, yellowness (b∗) value and lightness (L∗) value, and increased shear force and pH of breast muscle compared with those without dietary VA supplication. (3) Maternal or offspring VA did not affect the activities of total superoxide dismutase and glutathione peroxidase (GSH-Px) or the content of malondialdehyde; however, there was a significant interaction (P < 0.05) between maternal and offspring VA on the activity of GSH-Px in serum. (4) Dietary provision of 5,000 IU/kg VA increased (P < 0.05) the weight proportion of liver and bursa of fabricius, whereas maternal feeding with 21,600 IU/kg VA increased the hatchling BW. Maternal feeding with 5,400 and 21,600 IU/kg VA decreased (P < 0.05) splenic interferon-γ (IFN-γ) transcripts and increased (P < 0.05) those of interleukin-2 (IL-2) in the progeny. There were interactions (P < 0.05) between maternal and offspring VA on splenic IL-2, IL-1ß, and IFN-γ expression. In summary, maternal and offspring provision of VA both had influence on meat quality and immune function in progeny broilers. Dietary VA increased growth performance, whereas the maternal VA affected the initial body weight of progeny when hatched, but the difference in performance caused by maternal VA level was able to be eliminated by dietary VA supplementation. Therefore, offspring provision had greater importance than maternal VA in the production; however, both should be considered in broiler nutrition to achieve good meat quality and immune status of broilers.

Effects of Dietary Iron Level on Growth Performance, Immune Organ Indices and Meat Quality in Chinese Yellow Broilers.

The objective of three trials was to investigate the effects of dietary Fe on growth performance, immune organ indices and meat quality of Chinese yellow broilers during the whole growth period. A total of 1440 1-day-old, 1440 22-day-old, and 1080 43-day-old Lingnan yellow male broilers were randomly assigned to one of six dietary treatments with six replicates per treatment (40 birds per replicate for both 1 to 21 d and 22 to 42 d, 30 birds for 43 to 63 d). Additional Fe (0, 20, 40, 60, 80, and 100 mg/kg) was added as FeSO4 • H2O to the three basal diets (calculated Fe 50 mg/kg, analyzed 48.3, 49.1, 48.7 mg/kg, respectively). The calculated final dietary Fe concentrations in Starter, Grower and Finisher phases were 50, 70, 90, 110, 130, and 150 mg/kg. The results showed that average daily gain (ADG), average daily feed intake (ADFI) and feed conversion rate (FCR) of the broilers were not influenced by the different levels of Fe (p> 0.05). Weight indices of the spleen, thymus and bursa of Fabricius were not influenced (p > 0.05) by the different levels of Fe during three 21-day experimental periods. Hematocrit, and Fe contents of the liver and kidney were not affected by different levels of Fe (p> 0.05). The diet with 150 mg/kg of Fe increased the a* (relative redness) value of breast muscle compared to the 50 and 70 mg/kg diets at 24 h post mortem (p< 0.05). The diet with 90 mg/kg Fe increased the pH of breast muscle compared to broilers fed 50 or 150 mg/kg Fe (p < 0.05) 45 min after slaughter. The diet with 90 mg/kg Fe decreased drip loss of breast muscle compared to 150 mg/kg Fe (p< 0.05). These data suggest that feeding yellow-feathered broilers on a conventional corn-soy based diet satisfies their requirements without additional Fe at ages 1 to 21, and 22 to 42 d, while 90 mg/kg in the finisher phase improved meat quality, and from the QP (quadratic polynomial) models of the key meat quality variables, pH of breast muscle and drip loss of breast muscle, the optimal dietary Fe level was 89 to 108 mg/kg, and daily Fe fed allowance was 11 to 13 mg in the finisher phase (43 to 63 d).

Effects of dietary perilla seed oil supplementation on lipid metabolism, meat quality, and fatty acid profiles in Yellow-feathered chickens.

This study evaluated the effect of the dietary replacement of 1% lard (CT) with 1% perilla oil (PO), 0.9% perilla oil + 0.1% anise oil (PA), or 0.9% perilla oil + 0.1% ginger oil (PG) on indices of lipid metabolism, antioxidant capacity, meat quality, and fatty acid profiles from Yellow-feathered chickens at day 63. Compared with the CT chickens, those given perilla oil had decreased (P < 0.05) plasma lipid levels including triglycerides (TG), total cholesterol (TCH), and low-density lipoprotein cholesterol (LDL-C). Hepatic TG, TCH levels, and fatty acid synthase activity were also decreased (P < 0.05) in chickens fed diets containing perilla oil. Abdominal fat percentage was significantly decreased in birds fed the PG compared to CT diets. Birds fed the PA or PG diets had increased (P < 0.05) hepatic total SOD, glutathione peroxidase, and glutathione-S-transferase than in chickens given PO alone. In addition, the content of reduced glutathione (GSH) in breast muscle was lower (P < 0.05) in birds fed PO compared with those given PG, and the reverse was true for content of malondialdehyde. Compared with the CT diet, the PO diet decreased breast muscle shear values and increased yellowness (b*) of breast muscle (P < 0.05). Birds fed the PA or PG diets had meat with better overall acceptability than those fed the CT diet. Chickens fed perilla oil diets exhibited higher contents of α-linolenic acid (C18:3n-3), DHA (22:6n-3), polyunsaturated fatty acids, and n-3 fatty acids, together with a lower content of myristic acid (C14:0), palmitic acid (C16:0), stearic acid (C18:0), total saturated fatty acids, and n-6/n-3 ratio compared to controls (P < 0.05). These findings indicate that perilla oil has the potential to decrease lipid-related indices and improve fatty acid profiles of breast meat in chickens without adverse effect on antioxidant status or meat quality; this was even better when perilla oil was given together with anise oil or ginger oil.

Effects of equol on H2O2-induced oxidative stress in primary chicken intestinal epithelial cells.

This experiment investigated the antioxidant effects of equol on oxidative stress induced by H2O2 in chicken intestinal epithelial cells (IEC). IEC, from Lingnan yellow broiler chick embryos at embryonic day 18, were cultured in Dulbecco's modified Eagle's medium/F12. Cells were pretreated with 0, 10, 100, or 500 nM equol for 24 h before exposure to 300 µM H2O2 during a further 24 h. Oxidative damage was assessed by photomicrographs of cells, measuring cell proliferation, malondialdehyde (MDA) content, and antioxidative capacity from cellular total superoxide dismutase (T-SOD) activity, as well as the relative expressions of Nrf2, Bcl-2, SOD-1, GSH-Px3, Claudin-1 Treatment with 300 µM H2O2 caused serious damage to cells, with fewer normal intestinal epithelial cells, revealed by photomicroscopy. Treatment with 300 µM H2O2 significantly decreased live cell numbers compared with controls and prior treatment with equol had no effect in offsetting this action of H2O2 (P > 0.05). Compared with the cells treated just with H2O2, pre-treatment with 10, 100 and 500 nM equol significantly enhanced T-SOD activity (P < 0.05), while 10 and 100 nM equol before H2O2 significantly enhanced T-SOD activity compared with the untreated controls (P < 0.05). In cells pre-treated with 100 nM equol, the relative abundance of Nrf2 transcripts increased from the controls (P < 0.05) but expressions of Bcl-2, GSH-Px3, or SOD-1 were unaffected (P > 0.05). Pre-treatment with 10 and 100 nM equol significantly increased the transcript abundance of Claudin-1 (P < 0.05). Equol is shown here to protect IECs from oxidative damage by promoting the expression of antioxidant genes, increasing the activities of antioxidant enzymes, and by enhancing antioxidant capacity; 100 nM equol appeared to be the most effective concentration.

Equol Inhibits LPS-Induced Oxidative Stress and Enhances the Immune Response in Chicken HD11 Macrophages.

BACKGROUND/AIMS: There has been increasing recent attention on the antioxidative capacity of equol. This study tested the effect of equol on oxidative stress induced by lipopolysaccharide (LPS) and regulation of immunity in chicken macrophages. METHODS: Chicken HD11 macrophages were challenged with LPS (100 ng/mL) alone or with LPS (100 ng/mL) and (±)equol (10, 20, 40, 80, 160 µmol/L) together for 24h. Evaluated responses included the contents of malondialdehyde (MDA) and reduced glutathione (GSH), activities of total superoxide dismutase (T-SOD) and inducible nitric oxide synthase (iNOS), transcript abundance of superoxide dismutase 2 (SOD2), catalase (CAT), glutathione transferase (GST), Toll-like receptor 4 (TLR4), tumor necrosis factor alpha (TNFα) and interleukin-1 beta (IL-1ß), and contents of the cytokines TNFα, IL-1ß, interleukin-2 (IL-2) and interferon beta (IFNß). RESULTS: Exposure to LPS induced oxidative stress as contents of MDA increased and GSH decreased in LPS-treated cells (P < 0.05) compared to those in control cells. Compared to LPS alone, co-treatment with equol (20 µmol/L, 40 µmol/L or 80 µmol/L) reduced contents of MDA and increased those of GSH (both P < 0.05). Activity of T-SOD increased (P < 0.05) in cells treated with the higher contentration of equol (80 µmol/L or 160 µmol/L), however, all concentrations (20 µmol/L to 160 µmol/L) increased activity of iNOS (P < 0.05). The highest concentration of equol (160 µmol/L) increased SOD2 and GST transcripts (P < 0.05). Equol treatment increased transcripts of TLR4, TNFα and IL-1ß (P < 0.05). And there were similar changes in contents of IL-1ß, IL-2, IFNß and TNFα in the cells (P < 0.05). CONCLUSIONS: It concluded that equol can protect chicken HD11 macrophages from oxidative stress induced by LPS through reducing lipid peroxidation products and enhancing contents of antioxidants, and activities of relevant antioxidase enzymes; effects were also seen in gene expression related to the immune response and increased contents of cytokines. The optimal concentration of equol on antioxidation and immune enhancement in chicken macrophages was 40 µmol/L.