Growing concern for public health and food safety has prompted a special interest in developing nutritional strategies for removing waterborne and foodborne pathogens, including Salmonella. Strong links between manganese (Mn) and intestinal barrier or immune function hint that dietary Mn supplementation is likely to be a promising approach to limit the loads of pathogens in broilers. Here, we provide evidence that Salmonella Typhimurium (S. Typhimurium, 4 × 10⁸ CFUs) challenge-induced intestinal injury along with systemic Mn redistribution in broilers. Further examining of the effect of dietary Mn treatments (a basal diet plus additional 0, 40, or 100 mg Mn/kg for corresponding to Mn-deficient, control, or Mn-surfeit diet, respectively) on intestinal barrier and inflammation status of broilers infected with S. Typhimurium revealed that birds fed the control and Mn-surfeit diets exhibited improved intestinal tight junctions and microbiota composition. Even without Salmonella infection, dietary Mn deficiency alone increased intestinal permeability by impairing intestinal tight junctions. In addition, when fed the control and Mn-surfeit diets, birds showed decreased Salmonella burdens in cecal content and spleen, with a concomitant increase in inflammatory cytokine levels in spleen. Furthermore, the dietary Mn-supplementation-mediated induction of cytokine production was probably associated with the nuclear factor kappa-B (NF-κB)/hydrogen peroxide (H₂O₂) pathway, as judged by the enhanced manganese superoxide dismutase activity and the increased H₂O₂ level in mitochondria, together with the increased mRNA level of NF-κB in spleen. Ingenuity-pathway analysis indicated that acute-phase response pathways, T helper type 1 pathway, and dendritic cell maturation were significantly activated by the dietary Mn supplementation. Our data suggest that dietary Mn supplementation could enhance intestinal barrier and splenic inflammatory response to fight against Salmonella infection in broilers.

In addition to offering methionine, 2-hydroxy-4-methylthiobutyric acid (HMTBa) is also an organic acid and shows excellent bacteriostasis. Therefore, 3 experiments were conducted to determine the influence of drinking water supplemented HMTBa in combination with acidifier on performance, intestinal development, and microflora in broilers. The addition of different concentration (0.02–0.20%) of the blend of HMTBa and other acids significantly reduced the pH of water and exerted antimicrobial activity in dose-dependent manner in vitro. The outcomes from animal trial consisting of the drinking water with blended acidifier at 0.00, 0.05, 0.10, 0.15, and 0.20% indicated that the water with 0.15 or 0.20% acidifier resulted in linear and quadratic higher body weight at 42 d, gain and water consumption during 1 to 42 d (P < 0.05). In experiment 3, responding to graded blended acidifier in drinking water, birds receiving 0.10, 0.15, and 0.20% acidifier decreased the internal pH of gastrointestinal tract and muscle, and exhibited increased duodenal weight, length, villus high, and the ratio of villus high to crypt depth. Drinking water with 0.2% blended acidifier increased the abundance of probiotics (Bacteroidaceae, Ruminococcaceae, and Lachnospiraceae) and decreased the account of pathogenic bacteria such as Desulfovibrionaceae. Alternations in gut microflora were closely related to the metabolism of carbohydrate, amino acid, and vitamins. These findings, therefore, suggest that drinking water with 0.10 to 0.13% the combination HMTBa with acidifier might benefit to intestinal development and gut microbiota, and the subsequent produce a positive effect on the performance of broilers.

Fatty liver hemorrhagic syndrome is characterized by hepatic damage and hemorrhage impairing animal welfare in birds, which was well-known to be moderately relieved through dietary choline chloride supplementation in laying hens. Chinese herb has been proven to exert a positive role on hepatic health in human and rodents. Here, we investigated the effect of herbaceous mixture (HM), which consists of Andrographis paniculate, Silybum marianum, Azadirachta Indica, and Ocimum basilicum (2:3.5:1:2), on the hepatic lipid metabolism and health status in laying hens. A total of 240 Hy-line Brown hens (389-day-old) were randomly fed the basal diet with 0 mg/kg choline chloride (negative control, NC), 1,000 mg/kg choline chloride (control, Ctrl), or 300 mg/kg HM for 28 d. Birds fed HM diet exhibited lower serum triglyceride (TG) and low-density lipoprotein cholesterol concentration, and higher high-density lipoprotein cholesterol level than those received NC and Ctrl diets (P < 0.05). When compared to control and NC group, the diets with HM decreased the contents of total cholesterol and TG in liver, as well as upregulated the mRNA abundance of hepatic hormone-sensitive lipase and lipoprotein lipase. Meanwhile, the hepatic area and diameter of steatosis vacuoles were also decreased by dietary HM administration (P < 0.05), which accompanied by decreased serum alanine aminotransferase activity (P < 0.05). Birds fed HM diets enhanced the hepatic antioxidative capacity than those received NC and Ctrl diet. Dietary HM depressed the mRNA level of inflammatory cytokine as compared to NC but not Ctrl group. Collectively, the diet with 300 mg/kg HM has a favorable effect in decreasing the lipid deposition and protecting liver injury by alleviating hepatic oxidant stress and inflammation in post-peak laying hens.

The glucose metabolism of poultry draws wide attention as they have nearly twice the fasting blood glucose than that of mammals. To define the relationship between glucose metabolism and breed of chicken, the outcomes from different growth rate chickens showed that Arbor Acres (AA) broilers, a well-known fast-growing breed, had a lower fasting blood glucose concentration and glucose clearance rate when compared to Silky chickens, a Chinese traditional medicinal chicken with black skin and a slow growth rate. Moreover, AA broilers had a relatively slow rise in blood glucose in response to oral glucose solution than the Silky chickens on 21 and 42 d (P < 0.05), which is probably attributed to downregulated expression of pancreatic insulin (INS), and upregulated transcription of phosphoenolpyruvate carboxy kinase 1 (PCK1) and glucose transporter 2 (GLUT2) in the liver of AA broilers (P < 0.05). In response to feeding restriction from 7 to 21 d, both the fasting blood glucose and the response speed of AA broilers to oral glucose were increased on d 21 (P < 0.05), and the serum glucose concentrations after 3 weeks compensatory growth were improved by early feed restriction in AA broilers. Feed restriction could also upregulate the mRNA level of pancreatic INS on d 21 and 42, as well as decrease the expressions of PCK1, glucose-6-phosphatase catalytic (G6PC), and GLUT2 in the liver on d 21 (P < 0.05) when compared to the free feeding group. These results revealed that Silky chickens have a stronger capability to regulate glucose homeostasis than AA broilers, and feed restriction could improve the fasting blood glucose and the response to oral glucose of AA broilers.

Essential oils have been proven to exert multiple effects on growth performance, production quality, and health status in poultry nutrition, which is dependent on the component and/or dose of essential oils. Diets with the optimal combination of essential oils might be able to improve the performance traits and welfare of laying hens. Therefore, this study was conducted to evaluate the effects of dietary essential oils, which are composed of cinnamaldehyde with carvacrol or thymol, on performance, egg quality, and intestinal health in post-peak laying hens. A total of 384, 50-week-old Hy-line brown laying hens were randomly divided into three groups with 8 replicates of 16 birds each: (1) a basal diet (Ctrl), (2) a basal diet with 100 mg/kg of essential oils consisting of 4.5% cinnamaldehyde with 13.5% carvacrol (CAR+CIN), and (3) a basal diet containing 100 mg/kg of essential oils composed of 4.5% cinnamaldehyde with 13.5% thymol (THY+CIN). The CAR+CIN diet increased the feed consumption from 52 to 55 weeks more than the Ctrl and the THY+CIN diet. Compared with the Ctrl group, the addition of essential oils decreased the dirty egg rate (P = 0.07) in the whole trial period. Regarding egg quality, the birds that received the CAR+CIN and THY+CIN diets increased the eggshell strength (P = 0.099) or Haugh unit (HU, p = 0.03) at 54 weeks, respectively. Supplementation of both CAR+CIN and THY+CIN diets significantly increased the ratio of villus height to crypt depth in the duodenum through increasing villus height and decreasing crypt depth as well as upregulated the mRNA abundances of duodenal occluding and cadherin (P < 0.05). However, the treatment with dietary essential oils did not notably change the proportion of cecal microbiota and bacterial diversity. This study suggested that dietary supplementation of cinnamaldehyde with carvacrol or thymol, the active components of essential oils, could promote egg quality in post-peak laying hens, which might be associated with improved intestinal development and barrier.