Effects of carboxy methyl cellulose and thymol + carvacrol on performance,digesta viscosity and some blood metabolites of broilers

This study was conducted to evaluate the effects of thymol + carvacrol as plant essential oils on performance, digesta viscosity and some blood metabolites of broilers fed diets supplemented with carboxy methyl cellulose (CMC) and/or thymol+carvacrol. In a completely randomized design with a 2 × 3 factorial arrangement, two levels of CMC (0% and 2%) and three levels of thymol+carvacrol (0, 100 and 200 mg/kg) were used. Each of the six dietary treatments was fed to five replicate pens of 12 birds each from 0 to 42 days of age. Body weight gain (BWG), feed intake, feed conversion ratio (FCR), intestinal digesta viscosity and pH, plasma lipids and some blood metabolites were recorded. The inclusion of 2% CMC decreased (p < 0.05) BWG by 2.2% and increased FCR by 2.3% at 42 days of age. Carboxy methyl cellulose significantly increased the digesta viscosity and decreased serum total cholesterol, but had no significant effect on triglyceride, pH, HDL, LDL and other blood metabolites measured in this experiment. Thymol+carvacrol had no effect on feed intake, but significantly increased (p < 0.05) BWG from 1 to 42 days of age and improved FCR (p < 0.05) by the addition of 100 and 200 mg/kg thymol+carvacrol respectively. Inclusion of thymol+carvacrol at levels of 100 and 200 mg/kg in the diets decreased digesta viscosity and serum total cholesterol (p < 0.05) and also increased AST at a 200 mg/kg thymol+carvacrol without any effect on creatine kinase (CK). Thymol+carvacrol significantly increased total protein (TP), albumin and globulin (p < 0.05). In conclusion, CMC at an inclusion level of 2% of diet increased digesta viscosity and reduced growth performance. However, thymol+carvacrol decreased digesta viscosity and consequently improved the performance of broilers fed the CMC‐based diet. Therefore, thymol+carvacrol addition to viscose‐based diets might be helpful to alleviate the negative effects of viscous compounds in poultry diets.     

Combined effects of xylo-oligosaccharides and coated sodium butyrate on growth performance,immune function,and intestinal physical barrier function of broilers

This study was conducted to investigate the effects of dietary supplementation xylo-oligosaccharides (XOS), coated sodium butyrate (CSB), and their combination on growth performance, immune parameters, and intestinal barrier of broilers. A total of 192 1-day-old chicks were assigned to a 2 × 2 factorial design including two dietary additives (0 and 150 mg/kg XOS and 0 and 400 mg/kg CSB). This trial lasted for 42 days. CSB supplementation increased the thymus and bursa index, blood myeloperoxidase (MPO) activity, and IgG and IgM concentrations, whereas adding XOS only improved IgM concentration (p < .05). A significant interaction was observed for MPO activity. Furthermore, broilers fed CSB and their interaction exhibited increased ileal villus height/crypt depth (VH/CD) and goblet cells numbers in the ileum, as well as decreased ileal CD (p < .05). Broilers fed XOS and CSB individually showed higher ileal VH, the number of goblet cells in the duodenum and jejunum (p < .05). Moreover, XOS and CSB individual supplementation upregulated the expression of claudin3 in the ileum (p < .05). Simultaneously, a significant interaction was found for the ileal expression of claudin3. Overall, XOS and CSB supplementation could improve the development of immune organs, the small intestine morphology, and the intestinal physical barrier of broilers. Although no clear synergy of XOS and CSB was detected, the combination had positively affect broilers intestinal barrier and immune parameters.     

A deficient or an excess of dietary threonine level affects intestinal mucosal integrity and barrier function in broiler chickens

The aim of this study was to investigate the effects of deficient or excess of dietary threonine (Thr) levels on intestinal integrity and barrier function of broilers. A total of 432 1‐day‐old commercial broilers (Arbor Acre) were assigned to four experiment groups consisting of six replicates of 18 birds. The treatments were designed as follows: 85%, 100%, 125% and 150% of NRC (Nutrient requirements of poultry (9th edn). Washington, DC: The National Academies Press, 1994) recommendations. The results indicated that expressions of jejunal and ileal secretory immunoglobulin A (sIgA) mRNA were increased linearly or quadratically by increasing Thr (p < .05), and the highest sIgA mRNA abundance was obtained in 125% Thr level. Likewise, the intestinal sIgA content showed similar increasing trend with the intestinal sIgA gene expression in this instance. The high level of Thr inclusion upregulated mucin 2 (MUC2) mRNA expression in the jejunum and ileum (p < .05). In addition, on day 21, the expression levels of jejunal zonula occludens‐2 (ZO‐2) and ileal zonula occludens‐1 (ZO‐1) decreased then increased with increasing Thr level (p < .05), whereas, the mRNA expressions of occludin in the jejunum and ileum had no significant difference amongst groups (p >.05). On day 42, Thr treatments did not affect the mRNA abundance of measured genes in the jejunum and ileum (p > .05). These findings suggested that Thr might be a nutrient immunomodulator that affects intestinal barrier function, moreover, 125% of the NRC (1994) recommendations Thr level was optimum.     

Supplemental lipoic acid relieves post‐weaning diarrhoea by decreasing intestinal permeability in rats

Lipoic acid (LA) is a naturally existing substance which widely distributed in the cellular membranes and cytosol of animal cells. Its intracellular functions include quenching of free radicals and repairing oxidized proteins. The purpose of this study was to evaluate the effects of LA on post‐weaning diarrhoea using a rat model. Sixty weaned rats were fed either a basal diet or a LA‐supplemented diet, or a zinc oxide (ZnO)‐supplemented diet as a positive control. Rats in the LA and ZnO groups had better performance and reduced incidence of diarrhoea (p < 0.05). Both LA and ZnO treatments enhanced intestinal homeostatic and architecture, significantly decreased urinary lactulose to mannitol ratios (p < 0.05) and increased the expression of the intestinal mucosal tight junction proteins occludin (OCLN) and zonula occludens protein‐1 (ZO‐1) (p < 0.05). LA significantly increased the activities of antioxidant enzymes, and reduced glutathione while decreasing the levels of oxidative glutathione and malondialdehyde in the intestinal mucosa (p < 0.05). Furthermore, an in vitro study indicated that supplementation with LA in IEC‐6 intestinal epithelial cells significantly enhanced the expression of OCLN and ZO‐1 under hydrogen peroxide‐induced oxidative stress. Collectively, these results suggest that LA relieves post‐weaning diarrhoea by reducing intestinal permeability and improving antioxidant indices.     

Efficacy of essential oils combination on performance,ileal bacterial counts,intestinal histology and immunocompetence of laying hens fed alternative lipid sources

This study was carried out to assess the effects of a blend of herbal essential oils (namely Thymus vulgaris, Mentha piperita, Rosmarinus offisinalis and Anethum graveolens) and different dietary lipid sources on the performance, ileal bacterial enumeration, intestinal histological alterations and immune responses in laying hens. For this purpose, a total of 150 laying hens were randomly allocated to six experimental treatments with five replicates of five birds each. Dietary treatments consisted of three levels of a mixture of essential oils (0, 100 and 200 mg/kg) and two sources of lipid (soybean oil and fish oil containing different ratios of n‐6 to n‐3 fatty acids) fed to the animals during an 80‐days feeding trial. Findings indicated that dietary administration of fish oil not only increased significantly the spleen relative weight (p < 0.01) and the antibody titre against Newcastle virus (p < 0.05) but also led to reductions in liver relative weight (p < 0.05) and feed conversion ratio (p < 0.05). Moreover, the mixture of herbal essential oils brought about declines in hepatic relative weight, heterophile to lymphocyte ratio (p < 0.05) and intestinal pathogen populations (p < 0.01). Mention must also be made of the improvements it made in spleen weight (p < 0.01), antibody titres against SRBC (p < 0.01) and Newcastle virus (p < 0.05), villus height to crypt depth ratio (p < 0.01), goblet cell numbers (p < 0.05), lamina propria lymphatic follicle diameters (p < 0.01) and feed conversion ratio (p = 0.06). It may be claimed that the enhancements observed in the performance of laying hens fed fish oil and 200 mg/kg of the blend of essential oils could have potentially been associated with improved intestinal health indices as well as cellular and humoral immune responses.     

Transport stress induces pig jejunum tissue oxidative damage and results in autophagy/mitophagy activation

Pig transportation is associated with intestinal oxidative stress and results in destruction of intestinal integrity. Autophagy has been contributed to maintain cell homeostasis under stresses. The purpose of this study was to evaluate the effects of transport stress on morphology, intestinal mucosal barrier and autophagy/mitophagy levels in pig jejunum. A total of 16 finishing pigs were randomly divided into two groups. The control group was directly transported to the slaughterhouse and rested for 24 hr. The experimental groups were transported for 5 hr and slaughtered immediately. The results showed that transportation induced obvious stress responses with morphological and histological damage in jejunum accompanying with an elevated level of malondialdehyde (MDA; p < .05), endotoxin (LPS; p < .05), lactic dehydrogenase (LDH; p < .05) and a decreased level of serum superoxide dismutase (SOD; p < .05). Also, hemeoxy genase 1 (HO‐1; p < .01) as well as tight junction protein (claudin‐1 [p < .001], occludin [p < .05] and zonula occludens 1 [ZO‐1; p < 0.05]) levels were attenuated in jejunum tissue, and NADPH oxidase 1 (NOX1; p < .01) mRNA expression was up‐regulated. Further research indicated that transport stress could induce autophagy through increasing microtubule‐associated protein light chain 3 (LC3; p < .05) and autophagy‐related gene 5 (ATG5; p < .01) levels and suppressing p62 expression. Additionally, transport stress increased the protein levels of PTEN‐induced putative kinase 1 (PINK1; p < .05) and Parkin (p < .05) which was associated with mitophagy. In conclusions, transport stress could induce the destruction of intestinal integrity and involve in the intestinal mucosal barrier oxidative damage, and also contribute to activation of autophagy/mitophagy.     

Effects of oxidative stress induced by high dosage of dietary iron ingested on intestinal damage and caecal microbiota in Chinese Yellow broilers

The objective of this trial was to test the effects of oxidative stress induced by a high dosage of dietary iron on intestinal lesion and the microbiological compositions in caecum in Chinese Yellow broilers. A total of 450 1‐day‐old male chicks were randomly allotted into three groups. Supplemental iron (0, 700 and 1,400 mg/kg) was added to the basal diet resulting in three treatments containing 245, 908 and 1,651 mg/kg Fe (measured value) in diet respectively. Each treatment consisted of six replicate pens with 25 birds per pen. Jejunal enterocyte ultrastructure was observed by transmission electron microscopy. The results showed that a high dosage of dietary iron induced oxidative stress in broilers. Dilated endoplasmic reticulum (ER), autophagosome formation of jejunal enterocytes and decreased villi were caused by this oxidative stress. Compared to the control, concentration of the malondialdehyde (MDA) in jejunal mucosa in the 908 and 1,651 mg/kg Fe groups increased by 180% (p < .01) and 155% respectively (p < .01); activity of copper‐zinc superoxide dismutase (Cu/ZnSOD) increased in jejunum (p < .01); and the concentration of plasma reduced glutathione (GSH) decreased by 34.9% (p < .01) in birds fed 1,651 mg/kg Fe. Gene expression of nuclear factor, erythroid‐derived 2‐like 2 (Nrf2) and zonula occludens‐1 (ZO‐1), in the higher dietary Fe groups was enhanced (p < .05). Species of microbial flora in caecum increased caused by oxidative stress. The PCR‐DGGE (denaturing gradient gel electrophoresis) dendrograms revealed different microbiota (65% similarity coefficient) between the control and iron‐supplemented groups (p < .05). These data suggest high dosage of iron supplement in feed diet can induce oxidative stress in Chinese Yellow broilers, and composition of microbiota in the caecum changed. It implied there should be no addition of excess iron when formulating diets in Chinese Yellow broilers.     

Effect of probiotic supplementation on growth performance,intestinal morphology,barrier integrity,and inflammatory response in broilers subjected to cyclic heat stress

This study investigated the protective effects of probiotic on heat stress‐induced intestinal injury and inflammatory response in broilers. A total of 180 male broilers were randomly allocated to three treatments with four replicates each from 22 to 42 days of age. The broilers were either raised under thermoneutral (TN) conditions (23 ± 1°C) or subjected to cyclic heat stress (28–35–28°C for 12 hr daily). The broilers kept at TN conditions were fed a basal diet, and those exposed to heat stress were fed basal diets supplemented with or without probiotic at a dose of 1.5 × 10⁸ cfu/kg. Compared with the TN group, heat stress decreased (p < .05) the growth performance, reduced (p < .05) villus height and villus height: crypt depth ratio in intestinal mucosa, increased (p < .05) serum levels of D‐lactic acid on day 28 and endotoxin, TNF‐α and IL‐6 on day 42, and decreased (p < .05) serum IL‐10 content on day 42. Dietary supplementation of probiotic reversed (p < .05) all these changes except for the growth performance in heat‐stressed broilers. In conclusion, dietary inclusion of probiotic could improve intestinal morphology and barrier function, alleviate inflammatory response, but exert no ameliorative effect on growth performance of broilers under cyclic heat stress.     

Effects of chestnut tannins on intestinal morphology,barrier function,pro‐inflammatory cytokine expression,microflora and antioxidant capacity in heat‐stressed broilers

A study was conducted to evaluate the effects of chestnut tannins (CT) on intestinal morphology, barrier function, pro‐inflammatory cytokine expression, microflora and antioxidant capacity in heat‐stressed broilers. Four hundred 28‐day‐old male Ross 308 broilers were randomly assigned into four groups, with 10 replicates per group and 10 broilers per replicate. The broilers in the normal (NOR) group were kept at 22 ± 1°C and fed the basal diet, and each of the other three groups were treated with cyclic heat (33 ± 1°C from 0800 to 1800 and 22 ± 1°C from 1800 to 0800) and fed the basal diet with 0 (HT), 1 (CT1) or 2 (CT2) g of CT/kg of diet. The experiment lasted for 14 days. Compared with the HT group, broilers in the NOR and CT2 groups had higher (p < .05) average daily gain and villus height in the jejunum and lower serum d ‐lactate (p < .001) and diamine oxidase (p < .01) levels. The addition of 2 g CT/kg of diet increased the total antioxidant capacity (p < .001) and superoxide dismutase activities (p < .05) and zonula occludens‐1 mRNA expression level (p < .05) and decreased the malondialdehyde concentration (p < .01) and mRNA expression levels of interleukin‐6 (p < .001) and nuclear factor kappa B (p < .001) in the jejunal mucosa of heat‐stressed broilers. The populations of Escherichia coli and Clostridium in the jejunum (p < .01) and caecum (p < .05) of broilers in the HT group were higher than those in the NOR and CT2 groups. In conclusion, the addition of 2 g CT/kg of diet seemed to be a feasible means of alleviating the negative effects of heat stress on the growth performance and intestinal function of broilers.     

Effect of porcine glucagon‐like peptides‐2 on tight junction in GLP‐2R + IPEC‐J2 cell through the PI3k/Akt/mTOR/p70S6K signalling pathway

Because of rare glucagon‐like peptide‐2 (GLP‐2) receptor (+) cells within the gut mucosa, the molecular mechanisms transducing the diverse actions of GLP‐2 remain largely obscure. This research identified the naturally occurring intestinal cell lines that endogenously express GLP‐2R and determined the molecular mechanisms of the protective effects of GLP‐2‐mediated tight junctions (TJ) in GLP‐2R (+) cell line. (i) Immunohistochemistry results showed that GLP‐2R is localised to the epithelia, laminae propriae and muscle layers of the small and large bowels of newborn piglets. (ii) GLP‐2R expression was apparent in the cytoplasm of endocrine cells in IPEC‐J2 cell lines. (iii) The protein expressions of ZO‐1, claudin‐1, occludin, p‐PI₃K, p‐Akt, p‐mTOR and p‐p70^S6K significantly (p < 0.05) increased in GLP‐2‐treated IPEC‐J2 cells, and all of them significantly (p < 0.05) decreased when LY‐294002 or rapamycin was added. GLP‐2 improves intestinal TJ expression of GLP‐2R (+) cells through the PI₃k/Akt/mTOR/p70^S6K signalling pathway.     

Effects of a blend of thyme,peppermint and eucalyptus essential oils on growth performance,serum lipid and hepatic enzyme indices,immune response and ileal morphology and microflora in broilers

This study was conducted to evaluate the effect of a blend of essential oils (EOB) derived from thyme (Thymus vulgaris), peppermint (Mentha piperita) and eucalyptus (Eucalyptus globules) as a natural growth promoter. Five dosages (0 (CON), 50, 100, 150 and 200 ppm) of EOB were added daily to the drinking water to determine its effect on growth performance, carcass quality, blood biochemistry, immune response and ileal morphology in Ross 308 broiler chicks. A total of 500, 10‐day‐old male Ross 308 broilers were allocated into five treatments with four replicates each. Inclusion of EOB at 150 ppm improved (p < 0.05) body weight gain, feed conversion ratio and production index by 11.73, 10.81 and 24.13% compared to CON respectively. The inclusion of EOB at 100, 150 and 200 ppm increased (p < 0.05) carcass yield and thigh muscle compared to CON. Serum concentration of hepatic enzymes (alanine aminotransferase, aspartate aminotransferase and alkaline phosphatase) was decreased while the ileal villus height and ratio of villus height to crypt depth were improved (p < 0.05) in response to inclusion of 150 and 200 ppm of EOB compared to CON. The ileal Escherichia coli count was lower and Lactobacillus count was higher in EOB‐200 and EOB‐150, respectively, compared to CON at 21 and 42 days of age (p < 0.05). Antibody titre of Newcastle, bronchitis and infectious bursal disease was linearly increased (p < 0.05) by increasing supplemental level of EOB at day 4 post‐inoculation. Our results suggested that supplementation of EOB at the 150 ppm into drinking water during day 11–42 could improve growth performance, humoral immunity and ileal morphology and microflora in broilers, and thus, EOB has merit to be used as an alternative to antibiotic growth promoters.     

Impact of mash and crumble diets on intestinal amino acids transporters,intestinal morphology and pancreatic enzyme activity of broilers

The objective of this study was to evaluate effects of mash and crumble pre‐starter diets on pancreatic enzyme activity, intestinal morphology, gene expression of intestinal peptide and amino acid (AA) transporters of broilers. Broilers in battery cages were assigned to different feed forms of pre‐starter diet from 1 to 10 days of age. Significantly increased body weight gain (BWG), feed intake (FI) and lowered FCR were observed in birds fed crumble pre‐starter diet (CPD, p < 0.05). Feed forms had no effect on whole and small intestine length, but relative intestinal length and relative small intestinal length significantly increased in the broilers fed a mash pre‐starter diet (MPD, p < 0.05). Feeding CPD increased the weight of pancreas (p < 0.05), but relative weight of the pancreas was not influenced by treatments. Pancreatic protease and amylase activities significantly increased in the broilers fed CPD (p < 0.05) but the activity of lipase was not influenced. Crypt depth (CD) and villus height (VH) were higher in broilers fed CPD (p < 0.05) but villus width (VW), villus surface area (VSA) and villus height‐to‐crypt depth ratio (VCR) were not influenced by treatments. mRNA levels for peptide transporter 1 (PepT1), Na⁺‐independent cationic AA transporter1 (CAT1), Na⁺‐independent cationic and Na⁺‐dependent neutral AA transporter 1 (y⁺LAT1) and Na⁺‐dependent neutral AA transporter (B⁰AT) were lower in birds fed CPD (p < 0.05). There were no differences in mRNA abundance of Na⁺‐independent cationic and zwitterionic AA transporter (b^0,+AT) among treatments. Overall, the present data showed that feeding crumble diet during first 10 days of age, through higher FI, enhanced intestinal histomorphology, increased digestive enzyme activity is beneficial to growth performance of broilers. Indeed, dietary form can be an important factor in the expression of jejunal transporters.     

Effects of different protein sources completely replacing fish meal in low‐protein diet on growth performance,intestinal digestive physiology,and nitrogen digestion and metabolism in nursery pigs

The study compared the effects of selected proteins replacing fish meal in low‐protein diets on piglets’ growth performance, intestinal digestive physiology, and nitrogen digestion and metabolism. Five reduced CP, amino acid (AA)‐supplemented diets containing 4% of either S50, HP300, concentrated degossypolized cottonseed protein (CDCP), P50, or fish meal were assigned to six pens with 11 pigs for a 28‐day study period. Compared with fish meal, dietary proteins did not affect growth performance, apparent total tract digestibility (ATTD) of nutrients, serum hormone levels and biochemical parameters, apparent ileal digestibility (AID) of CP and most AA, colonic short‐chain fatty acid (SCFA) contents, duodenal and ileal morphology, digestive enzyme activity, and pH in small intestine of piglets. However, HP300, CDCP, and P50 decreased (p < 0.05) fecal N excretion per weight gain. AID of Ile in S50 and HP300 and Glu in P50 were improved (p < 0.05), and AID of Gly in other proteins was reduced (p < 0.05). S50 and P50 lowered (p < 0.05) the contents of colonic isobutyric and isovaleric. S50 and HP300 reduced (p < 0.05) jejunal villus height. CDCP increased (p < 0.05) the pepsin activity in stomach. S50, HP300, and CDCP decreased (p < 0.05) pH in the proximal colon. Overall, the selected proteins could completely replace fish meal in low‐protein diet without impairing piglets’ growth via maintaining intestinal digestive physiology, and nitrogen digestion and metabolism.     

N‐Acetyl‐d‐galactosamine prevents soya bean agglutinin‐induced intestinal barrier dysfunction in intestinal porcine epithelial cells

Soya bean agglutinin (SBA) is a glycoprotein and the main anti‐nutritional component in most soya bean feedstuffs. It is mainly a non‐fibre carbohydrate‐based protein and represents about 10% of soya bean‐based anti‐nutritional effects. In this study, we sought to determine the effects of N‐Acetyl‐D‐galactosamine (GalNAc or D‐GalNAc) on the damage induced by SBA on the membrane permeability and tight junction proteins of piglet intestinal epithelium (IPEC‐J2) cells. The IPEC‐J2 cells were pre‐cultured with 0, 0.125 × 10^?4, 0.25 × 10^?4, 0.5 × 10^?4, 1.0 × 10^?4 and 2.0 × 10^?4 mmol/L GalNAc at different time period (1, 2, 4 and 8 hr) before being exposed to 0.5 mg/ml SBA for 24 hr. The results indicate that pre‐incubation with GalNAc mitigates the mechanical barrier injury as reflected by a significant increase in trans‐epithelial electric resistance (TEER) value and a decrease in alkaline phosphatase (ALP) activity in cell culture medium pre‐treated with GalNAc before incubation with SBA as both indicate a reduction in cellular membrane permeability. In addition, mRNA levels of the tight junction proteins occludin and claudin‐3 were lower in the SBA‐treated groups without pre‐treatment with GalNAc. The mRNA expression of occludin was reduced by 17.3% and claudin‐3 by 42% (p < 0.01). Moreover, the corresponding protein expression levels were lowered by 17.8% and 43.5% (p < 0.05) respectively. However, in the GalNAc pre‐treated groups, occludin and claudin‐3 mRNAs were reduced by 1.6% (p > 0.05) and 2.7% (p < 0.01), respectively, while the corresponding proteins were reduced by 4.3% and 7.2% (p < 0.05). In conclusion, GalNAc may prevent the effect of SBA on membrane permeability and tight junction proteins on IPEC‐J2s.     

The effect of Epigallocatechin‐3‐gallate on small intestinal morphology,antioxidant capacity and anti‐inflammatory effect in heat‐stressed broilers

This study was to investigate the effects of Epigallocatechin‐3‐gallate (EGCG) on intestinal morphology, antioxidant capacity and anti‐inflammatory response in heat‐stressed broiler. A total of 192 2‐week‐old Arbour Acres broilers chickens were divided into four groups with six replicates per group and eight chickens per replicate: one thermoneutral control group (28°C, group TN), which was fed the basal diet; and three cyclic high‐temperature groups (35°C from 7:00 to 19:00 hr; 28°C from 19:00 hr to 7:00 hr, heat stress group), which were fed the basal diet supplementation with EGCG 0 mg/kg (group HS0), 300 mg/kg (group HS300) and 600 mg/kg (group HS600). The gut morphology and intestinal mucosal oxidative stress indicators, as well as intestinal barrier‐related gene expression, were analysed. The results showed that compared with group TN, heat stress reduced the villus height (VH), activities of glutathione peroxidase (GSH‐Px), superoxide dismutase (SOD)and catalase (CAT), increased the crypt depth (CD) and malondialdehyde (MDA)content at 21, 28 and 35 days (p < 0.05). After the heat‐stressed broilers were supplemented with EGCG, VH, VH/CD (V/C), and the activities of GSH‐Px, SOD and CAT were increased, and CD and MDA content were reduced compared with those in group HS0 without EGCG supplementation at 21, 28 and 35 days (p < 0.05). The EGCG supplementation promoted the gene expression of nuclear factor‐erythroid 2‐related factor 2 (Nrf2), Claudin‐1, Mucin 2 (Muc2) and alleviated the nuclear factor‐kappa B (NF‐κB) and lipopolysaccharide‐induced tumour necrosis factor (LITAF) gene expression compared with group HS0 (p < 0.05). Moreover, intestinal morphology was strongly correlated with antioxidant ability and inflammatory response. In conclusion, EGCG alleviated the gut oxidative injury of heat‐stressed broilers by enhancing antioxidant capacity and inhibiting inflammatory response.     

Montmorillonite improved the intestinal mucosal barrier functions of laying hens in late production

This study was conducted to investigate the effects of dietary supplementation with montmorillonite (MMT) on performance, intestinal endotoxin concentration, gut mucosal oxidation status, intestinal morphology and permeability, and immunological barrier function of laying hens during late production. Four hundred and eighty 75‐week‐old laying hens (Lohmann Brown) were randomly assigned to five treatments with eight replicates per treatment and 12 hens in each replicate. The hens were fed the basal diet supplemented with 0 (control), 0.3, 0.6, 0.9, or 1.2 g MMT/kg for 70 days. Compared with the control, supplemented with 0.9 g MMT/kg increased egg mass significantly (p < 0.05) during weeks 1–5 of the experiment. Supplemented with 0.6 and 0.9 g MMT/kg also increased the endotoxin concentration in the ileal digesta (p < 0.05), but decreased the MDA concentration in the ileum significantly (p < 0.05). The T‐AOC in the jejunum of the group fed 0.3 g MMT/kg was significantly increased (p < 0.05). Compared with the control, the villus height:crypt depth of ileum from the groups fed 0.6, 0.9, and 1.2 g MMT/kg increased significantly (p < 0.05). The sIgA concentration of jejunum in the groups fed 0.6 and 0.9 g MMT/kg was higher (p < 0.05) than the control. The MMT supplementation linearly increased (p < 0.05) the mRNA expression of claudin‐1 and claudin‐5 in the jejunum. Dietary MMT supplementation down‐regulated the mRNA expression of NF‐κB P65 and TNF‐α in the jejunum in a linear and quadratic manner (p < 0.05). The IL‐1β mRNA expression of jejunum in the group fed 0.6 g MMT/kg was lower (p < 0.05) than the control. In conclusion, dietary supplementation with MMT may improve the gut barrier functions and suggests that 0.9 g/kg of MMT in diets may be the optimal supplemental level for laying hens in late production.     

Effects of a protected inclusion of organic acids and essential oils as antibiotic growth promoter alternative on growth performance,intestinal morphology and gut microflora in broilers

This experiment was conducted to investigate the effects of protected essential oils and organic acids mixture on poultry feeding. A total of 450 1‐day‐old Cobb 500 chicks were randomly allotted into three treatments with six replicates. Birds were offered a basal diet (C), basal diet with 0.15 g/kg enramycin premix (A) and basal diet with 0.30 g/kg protected essential oils and organic acids mixture product (P). The results showed that protected essential oils and organic acids mixture supplementation reduced average daily feed intake and ratio of feed to gain (F/G) at 22–42 days of age, and F/G during 1–42 days of age also declined (P < 0.05). Product supplementation improved spleen index, villus height and crypt depth of the jejunum at 42 days when compared with the control (P < 0.05). In addition, secretory immunoglobulin A level of ileal mucosa and trypsin and chymotrypsin activities of intestinal tract were higher in the P treatment. Bacterial sequence analysis of the intestinal tract revealed that protected essential oils and organic acids mixture supplementation changed gut microflora mainly in Lactobacillus. These data suggested that dietary mixture of organic acids and essential oils addition could be used in the poultry industry as an antibiotic growth promoter alternative.     

饲粮中添加不同植物精油对肉仔鸡生长性能、肠道发育、免疫器官指数及屠宰性能的影响

本试验通过在基础饲粮中添加不同植物精油产品,旨在研究其对肉仔鸡生长性能、肠道发育、免疫器官指数及屠宰性能的影响。选取1日龄罗斯308商品肉仔鸡公雏2 304只,随机分为6个组,每个组12个重复,每个重复32只。1组为对照组,饲喂基础饲粮;2组为负对照组,在基础饲粮中添加抗生素(20 mg/kg维吉尼亚霉素);3~6组在基础饲粮中各添加1种植物精油产品,分别为100 mg/kg植物精油1(含5%香芹酚,EO1组)、300 mg/kg植物精油2(含5%香芹酚,EO2组)、300 mg/kg植物精油3(含8%香芹酚和百里香酚混合物,EO3组)以及300 mg/kg植物精油4(含2%香芹酚和百里香酚混合物,EO4组)。试验期39 d。结果表明:1)与对照组相比,负对照组以及EO2组肉仔鸡22~31日龄料重比显著降低(P0.05),分别降低了2.58%、3.51%;与对照组相比,负对照组肉仔鸡1~38日龄平均日增重升高,料重比降低,但差异均不显著(P0.05);饲粮中添加不同植物精油未显著影响肉仔鸡1~38日龄平均日增重、平均日采食量和料重比(P0.05)。2)与对照组相比,饲粮中添加不同植物精油有提高肉仔鸡39日龄十二指肠绒毛高度的趋势(P=0.075 3),绒毛高度/隐窝深度值也有所提高(P0.05)。3)各组之间肉仔鸡22和39日龄脾脏指数和法氏囊指数均差异不显著(P0.05)。各组之间肉仔鸡胴体出成率、胸肌率、腿肌率、翅重率以及腹脂率均差异不显著(P0.05)。由此可见,本试验条件下,饲粮中添加不同植物精油对肉仔鸡生长性能的改善不显著,但可促进十二指肠绒毛发育。     

Effects of guanidinoacetic acid on growth performance,creatine metabolism and plasma amino acid profile in broilers

The objective of this study was to assess the effects of guanidinoacetic acid (GAA) on growth performance, creatine deposition and blood amino acid (AA) profile on broiler chickens. In Exp. 1, a total of 540 one‐day‐old Arbor Acres male broilers (average initial body weight, 45.23 ± 0.35 g) were divided randomly into five treatments with six replicates of 18 chicks each. Broilers were fed corn–soybean meal‐basal diets supplemented with 0, 600, 800, 1,000 or 1,200 mg/kg GAA for 42 days respectively. Results showed that dietary GAA inclusion increased average daily gain (ADG) and improved gain‐to‐feed ratio (G:F) from 1 to 42 days (p < 0.01). However, average daily feed intake was unaffected by dietary supplementation of GAA. As GAA inclusion increased, the contents of creatine in plasma and kidney were increased (linear, p < 0.01), while the contents of GAA and creatine in liver were decreased (linear, p < 0.01). Similarly, GAA supplementation was inversely related to concentrations of most essential AA in plasma. In Exp. 2, a total of 432 one‐day‐old Arbor Acres male broilers (average initial body weight, 39.78 ± 0.58 g) were divided randomly into four treatments with six replicates of 18 chicks each. Birds were fed a corn–soybean meal‐basal diet supplemented with 0, 200, 400 or 600 mg/kg GAA for 42 days respectively. Dietary inclusion of 600 mg/kg GAA significantly increased ADG and G:F of broilers (p < 0.05). In conclusion, dietary supplementation of 600–1,200 mg/kg GAA can effectively improve the growth performance in broiler chickens by affecting creatine metabolism and utilization efficiency of essential AA, and 600 mg/kg GAA is the minimum dose for improving performance.     

Gene expression and morphological changes in the intestinal mucosa associated with increased permeability induced by short‐term fasting in chickens

Short‐term fasting for 4.5 and 9 hr has been demonstrated to increase intestinal permeability (IP) in chickens. This study aimed to investigate the effects of 0, 4.5, 9 and 19.5 hr fasting on intestinal gene expression and villus‐crypt architecture of enterocytes in jejunal and ileal samples. On day 38, Ross‐308 male birds were fasted according to their group and then euthanised. Two separate intestinal sections (each 2 cm long, jejunum and ileum) were collected. One section was utilised for villus height and crypt depth measurements. The second section was snap‐frozen in liquid nitrogen for quantitative polymerase chain reaction (qPCR) analysis of tight junction proteins (TJP) including claudin‐1, claudin‐3, occludin, zonula occludens (ZO‐1, ZO‐2), junctional adhesion molecules (JAM) and E‐cadherin. Additionally genes involved in enterocyte protection including glucagon‐like peptide (GLP‐2), heat‐shock protein (HSP‐70), intestinal alkaline phosphatase (IAP), mammalian target of rapamycin (mTOR), toll‐like receptors (TLR‐4), mucin (MUC‐2), cluster differentiation (CD‐36) and fatty acid‐binding protein (FABP‐6) were also analysed. Normally distributed data were analysed using one‐way analysis of variance ANOVA. Other data were analysed by non‐parametric one‐way ANOVA. Villus height and crypt depth were increased (p < .05) only in the ileum after fasting for 4.5 and 9 hr compared with non‐fasting group. mRNA expression of claudin‐3 was significantly reduced in the ileum of birds fasted for 9 and 19.5 hr, suggesting a role in IP modulation. However, all other TJP genes examined were not statistically different from control. Nevertheless, ileal FABP‐6 of all fasted groups was significantly reduced, which could possibly be due to reduced bile acid production during fasting.