Transport and expression of transporters for 3-O-methyl-D-glucose and L-methionine along the intestine of broiler chickens receiving different methionine supplements

The present study hypothesized that supplementation of different methionine (Met) sources might influence the intestinal absorption of l-Met and 3-O-methyl-d-glucose (3-OMG) in broilers. In a completely randomized study, a total of 53 Cobb500 broilers (30 males and 23 females) received a grower-finisher diet that was either not supplemented with Met (Met + Cys, 0.49 %; control) or supplemented with either 0.27 % l-Met, 0.27 % DL-Met or 0.47 % DL-2‑hydroxy-4-(methylthio) butanoic acid (HMTBA). After ≥10 days on the diets, uptakes of 3-OMG and l-Met were measured in duodenum, mid-jejunum and caecum at 50 µM and 5 mM concentrations in Ussing chambers, each in the presence and absence of Na+. We also investigated the mRNA expression of apical glucose and Met transporters. Dietary supplements had no effect on 3-OMG and l-Met uptakes (P > 0.05), except for male broilers receiving DL-Met or DL-HMTBA, that showed higher jejunal uptakes of l-Met than control at 5 mM (P < 0.001). Except for l-Met uptakes at 5 mM, tissue × sodium interactions (P ≤ 0.05) for 3-OMG and l-Met uptakes verified higher uptakes in jejunum compared to duodenum and caecum; with higher uptakes in the presence vs. absence of Na+ in jejunum only. In duodenum, uptakes of l-Met and 3-OMG at 50 µM concentration were higher in males vs. females. Expression of SGLT1, B0AT1, ATB0,+ and rBAT, but not ASCT1, were lowest in caecum (P ≤ 0.05). Expression of B0AT1 was higher in males vs. females (P ≤ 0.05). Expression of ASCT1 was higher with DL-Met and DL-HMTBA supplements compared to l-Met and control (P ≤ 0.05). These findings indicate that jejunum is the main intestinal segment for Na+-dependent l-Met and 3-OMG absorption in broilers with minor effects of dietary Met source. A sexual dimorphism for duodenal nutrient uptake and mRNA abundance of B0AT1 was congruent with the more efficient growth performance of male chickens known from the literature.

The in ovo screening of 27 single essential oils showed selective effects on hatchability, performance and gene expression relevant to gut functions in broilers at hatch

The early post-hatching phase remains to be one of the most vulnerable phases in broiler production. Some essential oils have been reported to improve gut health and growth in broiler chickens when applied to post-hatching diets. However, in-feed applications are unable to prevent the health challenges observed immediately after hatching. Thus, pre-hatch interventions need to be considered. A research project was developed with the aim of investigating the impact of in ovo application of 27 selected essential oils (EOs) on foetal development with emphasis on gut integrity in broiler hatchlings. The eggs were incubated under standard conditions until day 17.5, when 1 mL of each EO preparation (5 µL EO + 5 µL polysorbate-80 + 990 µL saline) was injected into the amnion. Hatchability, body weight and organ weights (residual yolk, gizzard-proventriculus, intestines, liver, and heart) were measured at hatch. Five essential oils eugenol, clove, tea tree, lemongrass, and thyme, significantly (P < 0.05) reduced hatchability (66.67 %, 58.33, 83.30 and 83.30 %) compared to the saline (96.80 %), were discarded from the rest of the study. The other 22 essential oils were investigated in a second phase to assess their impact on expression of gut biomarkers including: a) jejunum integrity; b) digestive enzymes and nutrient transporters; and c) immune system. The results indicated that lemon myrtle significantly increased and oregano EO decreased body weight at hatch (BW0) compared to the saline (P < 0.05). Ylang ylang, clary sage, bergamot, lemon myrtle, and black pepper upregulated the expressions of biomarkers regulating gut integrity and barrier functions (ZO-1, ZO-2, CLDN1, MARVELD2, EGFR and EGF), nutrients transporters (EAAT3, PEPT1, I-FABP1, SGLT1), and digestive enzymes (APN, SI). Ylang ylang, turmeric acid, star anise, clary sage, and black pepper upregulated the expression of gut immunity biomarkers IL1B, IL10, IGMH, CD3D, and BU1 compared to the saline. In conclusion, in ovo delivery of selected EOs has the potential to improve embryonic development relevant to nutrient digestion and absorption, gut integrity and immunity in broilers.

Impact of early postbiotic supplementation on broilers' responses to subclinical necrotic enteritis

Necrotic enteritis (NE), an enteric disease caused by Clostridium perfringens, results in damage to the intestinal epithelial lining disrupting its function, nutrient absorption, and utilization. This study evaluated the effects of in ovo and post-hatch applications of a Saccharomyces cerevisiae-based postbiotic on performance and nutrient transporter genes of broilers during a NE challenge. At embryonic d 18, Ross 708 fertile eggs were injected with 0.2 mL of either water or postbiotic. A total of 288 male hatchlings were assigned to one of the following treatment groups: 1) NC (in ovo water injection, no challenge); 2) PIW (postbiotic in ovo and in drinking water, no challenge); 3) NC+ (NC with NE challenge); and 4) PIW+ (PIW with NE challenge). On d 14, all birds in the NE-challenged groups were orally gavaged with 3,000 Eimeria maxima sporulated oocysts followed by two doses of ∼1×108 CFU/mL/bird of C. perfringens on d 19 and d 20. Hatchability, weekly performance, intestinal lesion scores, and mRNA abundance of nutrient transporters in the jejunum and ileum were assessed. Data were analyzed by 2-way ANOVA in JMP and significance between treatments identified by LSD test (P ≤ 0.05). A significant postbiotic treatment and NE challenge interaction was observed in performance during d 21-28 with a greater ADG in PIW compared to NC and PIW+. Lesion scores in the jejunum and ileum were significantly reduced in PIW+ compared to NC+. On d 7, mRNA abundance of SGLT1 was significantly greater in PIW compared to the NC group. On d 14, birds in PIW had greater levels of GLUT2 and EAAT3 than NC group. No significant interaction effects were observed on d 21. PIW+ had significantly greater EAAT3 mRNA levels compared to PIW in jejunum and PIW and NC+ in ileum on d 28. In conclusion, in ovo and water supplementation of this postbiotic presents a potential to improve the performance, ameliorate pathology detriments associated with NE, and positively regulate the mRNA levels of key nutrient transporters during NE challenge.

Early addition of enzyme-treated soybean in the diet improves amino acid absorption and protein digestibility by promoting digestive enzyme activity in broilers

Early nutritional regulation has become a research hotspot. The present study was undertaken to assess dietary early addition enzyme-treated soybean meal (ESBM) on nutrient digestibility, amino acid absorption, and intestinal development of broilers. Four hundred and fifty 1-day-old broilers were divided into three groups with 10 replicates of 15 broilers and fed with a basic diet, 2.5 or 5% ESBM during 1-10 days. Then, all groups were fed the same basic diets until 42 d. The obtained results indicated that supplementation of ESBM in early stage resulted in heavier BW and a better feed conversion ratio during the experimental periods compared with the control group. Supplementing the broiler's diet with 5% ESBM led to enhance digestibility of DM, CP and decrease abdominal fat yield (P < 0.05). Meanwhile, 5% ESBM in the early diet increased villus height (P < 0.05, d 21) and reduced the crypt depth in jejunum and ileum (P < 0.05, d 42). Dietary 5% ESBM supplementation improved enzyme activity and upregulated nutrient transporters expression in jejunum, increased plasma amino acid (AA) concentrations (P < 0.05, d 10). In conclusion, our data demonstrated that supplementation ESBM promote intestinal development, upregulate AAs and peptide transporters gene expression for physiological absorption of AAs, and improve protein digestibility caused by intestinal enzyme activity, thereby improving growth performance.

Linking gastrointestinal tract structure, function, and gene expression signatures to growth variability in broilers: a novel interpretation for flock uniformity

Variation in body weight (BW) within broiler flocks is a significant challenge in poultry production. Investigating differences in gut-related parameters between low (LBW) and high BW (HBW) chicks may provide insights into the underlying causes of BW heterogeneity. 908 day-old male broiler chicks were reared until d 7 and then ranked into LBW and HBW groups. Thereafter, performance parameters were compared between BW groups periodically. On d 7, 14, and 38, visceral organ characteristics, intestinal permeability, and duodenal and ileal histomorphology were examined. Expression profiles were analyzed for 79 ileal genes related to gut barrier function, immune function, nutrient transport, gut hormones, nutrient receptors, metabolism, and oxidation using high-throughput qPCR. Student's t-tests were performed to compare measurements. Multivariate statistics, including partial least square regression (PLSR) analysis, were applied to identify combinations of key genes discriminating BW groups, offering predictive capability for phenotypic variations. The HBW group remained heavier at each timepoint, which could be explained by higher feed intake. The HBW group had shorter relative small intestine length but higher villus height and villi height/crypt depth ratios. The LBW group demonstrated increased intestinal permeability on d 38. The LBW group showed upregulation of immune response genes including TNF-α on d 7 and CYP450 on d 38, while the HBW group showed higher AHSA1 and HSPA4 expressions on d 7. The LBW group had upregulation of the metabolism genes mTOR and EIF4EBP1 on d 7 and the satiety-induced hormone cholecystokinin on d 14, while the HBW group tended to increase expression of the hunger hormone ghrelin on d 38. Genes related to gut barrier function, nutrient transport, and oxidation categories were consistently upregulated in the HBW group. PLSR models revealed 4, 12, and 11 sets of key genes highly predictive of BW phenotypes on d 7, 14, and 38, respectively. These findings suggest that growth rates are linked to the intestinal size, structure, and function of broiler chickens, offering insights into the underlying mechanisms regulating BW.

Sex-specific genetic parameter estimates of body weight in Mazandaran indigenous chickens

Body weight is an economically important trait in poultry that shows sexual dimorphism (SD). In the present study, variation in SD in Mazandaran native chickens was investigated in terms of the (Co) variance components and genetic parameters of body weight between males and females. Studied traits were body weights at hatch (BW1), 8 weeks (BW8) and 12 weeks of age (BW12). Also, for weight at sexual maturity (WSM) covariance components were only estimated in females. Cross-sex direct and maternal correlations were also estimated for studied traits except for WSM. For this purpose, a deep 21-generation pedigree and body weight data (57,576 BW1, 72,925 BW8, 62,727 BW12 and, 42,496 WSM) were used. Evaluation of SD of body weight was performed using six bivariate animal models with and without considering the genetic and permanent maternal environmental effects under the restricted maximum likelihood method in WOMBAT software. Model with direct additive genetic effects and maternal genetic effects without covariance between them was identified as the best model for BW1 and BW8. The Model including direct additive genetic effects and permanent maternal environmental effects was the best model for BW12 and WSM. Direct heritability (h2) estimates for BW1, BW8 and, BW12 were, respectively, 0.05 ± 0.013, 0.17 ± 0.02 and, 0.25 ± 0.03 in males and, 0.05 ± 0.012, 0.15 ± 0.01 and 0.21 ± 0.01 in females. Also, the direct heritability of WSM based on univariate analysis in females was estimated to be 0.40 ± 0.01. Maternal heritability (h m 2 ) varied from 0.39 ± 0.01 (BW1) to 0.04 ± 0.009 (BW8) in males, and 0.36 ± 0.10 (BW1) to 0.04 ± 0.006 (BW8) in females. The correlation between direct genetic effects between males and females for BW1 was not significantly different from one. The direct genetic correlation between the two sexes for BW8 and BW12 was significantly different from 1 concluding that these traits are dimorphic in terms of direct genetic effects and therefore independent selection in both sexes is possible.

The effect of sex and dietary crude protein level on nutrient transporter gene expression and cecal microbiota populations in broiler chickens

It is well known that male and female broilers differ in their growth performance and that many physiological factors contribute to this difference. The aim of this experiment is to investigate if there are differences between male and female broilers in cecal microbiota and nutrient transporter gene expression and if these differences play a role in the growth performance of broilers. The possible effect of protein level and its interaction with sex on microbiota and expression of the nutrient transporters were also investigated. Samples were collected from male and female birds fed either standard crude protein (SCP) or reduced crude protein diets (RCP) at the age of d 35. The experiment was designed as a 2 × 2 factorial arrangement of treatments consisting of 448 Cobb 500 broilers assigned to 32-floor pens with 4 treatments, 8 replicates, and 14 birds per pen for performance measurements. The factors were sex (male or female) and dietary crude protein (CP) level (standard or reduced). Body weight gain (BWG), feed intake and feed conversion ratio were recorded for each pen. Sex had a significant effect on BWG and FCR (P < 0.001) where males had a significantly higher BWG and better FCR compared to females. There was a significant interaction between sex and protein level on feed intake (FI) (P < 0.05), where male birds had a higher FI compared to female birds only when the birds were fed SCP but not RCP diets. There was a significant interaction between CP level and sex on the expression of CAT2 (P = 0.02) and PEPT2 (P = 0.026) where the genes were significantly upregulated in females but only when the RCP diet was fed. The RCP diet upregulated the expression of BoAT (P = 0.03) as a main effect. Female birds had significantly higher expression of the PepT-2 gene compared to the males. The alpha diversity of the cecal microbiota showed differences among the treatments. The Shannon diversity index was statistically higher (P = 0.036) for males fed the SCP diet and the Chao1 index for evenness was statistically higher (P = 0.027) in females fed the SCP diet. There was also a difference in the relative abundance of the 15 most common genera found in the cecal content of the broilers in this experiment and lastly, the differential composition of microbiota between the different treatments was also significantly different. This study suggests that chickens are able to compensate for a reduction in AA substrates when fed a low CP diet through the upregulation of certain AA transporters, females may adapt to low CP diets better by such upregulation compared to males, and lastly, sex has an effect on the cecal microbial population and these differences contribute towards the performance differences between male and female broilers.

Intra-Amniotic Administration of Cashew Nut (Anacardium occidentale L.) Soluble Extract Improved Gut Functionality and Morphology In Vivo (Gallus gallus)

Cashew nuts are rich in dietary fibers, monounsaturated fatty acids, carotenoids, tocopherols, flavonoids, catechins, amino acids, and minerals that offer benefits for health. However, the knowledge of its effect on gut health is lacking. In this way, cashew nut soluble extract (CNSE) was assessed in vivo via intra-amniotic administration in intestinal brush border membrane (BBM) morphology, functionality, and gut microbiota. Four groups were evaluated: (1) no injection (control); (2) H₂O injection (control); (3) 10 mg/mL CNSE (1%); and (4) 50 mg/mL CNSE (5%). Results related to CNSE on duodenal morphological parameters showed higher Paneth cell numbers, goblet cell (GC) diameter in crypt and villi, depth crypt, mixed GC per villi, and villi surface area. Further, it decreased GC number and acid and neutral GC. In the gut microbiota, treatment with CNSE showed a lower abundance of Bifidobacterium, Lactobacillus, and E. coli. Further, in intestinal functionality, CNSE upregulated aminopeptidase (AP) gene expression at 5% compared to 1% CNSE. In conclusion, CNSE had beneficial effects on gut health by improving duodenal BBM functionality, as it upregulated AP gene expression, and by modifying morphological parameters ameliorating digestive and absorptive capacity. For intestinal microbiota, higher concentrations of CNSE or long-term intervention may be necessary.

Influence of sex and rearing method on performance and flock uniformity in broilers-implications for research settings

Male and female broiler chickens differ in their growth performance, carcass part weights and nutrient requirements. The potential reasons for these differences have been explored by looking at differences in nutrient digestibility, nutrient transporter gene expression as well as gut microbiota populations between male and female birds. Studies have shown that male broilers have higher crude protein requirements compared to female broilers. The expression of monosaccharide and amino acid transporters show conflicting results as expression depends on the interactions between sex and bird age and breed as well as which tissue is sampled. Differences in microbiota populations between the genders were reported which may contribute towards performance differences, however research in this area is limited. The differences observed between the sexes contribute to increased variation in nutrition trials, and the potential to rear birds as equally mixed-sex becomes an option to reduce the variation introduced by the sex effect. Difference in rearing options obviously would only be feasible provided a quick, practical and cost-effective method of sexing birds is available, a topic that is also discussed in this review.

Development of small intestine and sugar absorptive capacity in goslings during pre- and post-hatching periods

This study was conducted to investigate the development patterns of small intestine, intestinal morphology, disaccharidase activities, and sugar transporter gene expression in goslings during pre- and post-hatching periods. Small intestine was sampled on embryonic d 23 and 27, day of hatch, and d 1, 4, and 7 post-hatching. A total of 18 eggs with the breed of Jilin White geese were selected at each sampling timepoint for measuring relevant parameters. Three eggs were considered as a group, with 6 groups in each sampling timepoint. Rapid development of small intestine was observed around the hatching, of which jejunum and ileum had relatively higher development rates. Villus surface area from three intestinal segments started to increase on embryonic d 27, and kept relatively stable during day of hatch to d 1 post-hatching, and following increased till d 7 post-hatching. A high priority of villi enrichment was observed in duodenum and jejunum. The activity of disaccharidase increased before hatching and kept relatively high-level post-hatching, of which the activity of disaccharidase was highest in jejunum. The expression of sugar transporter gene increased prior to hatching and then decreased post-hatching, of which jejunum and duodenum were sites with high sugar transporter gene expression. Rapid development in intestinal morphology, disaccharidase activities, and sugar transporter gene expression around the hatching indicated that goslings have high potential to digest and/or assimilate carbohydrates during its early-life, which provided a preparation for further digestion of exogenous feed. This study provided a profile of development patterns for intestinal morphology, disaccharidase activities, and sugar transporter gene expression in goslings, which was beneficial to understanding the characteristics of nutrient absorption during the early-life of goslings.

Effects of three probiotics and their interactions on the growth performance of and nutrient absorption in broilers

The purpose of this study was to investigate the effects of three probiotics and their interactions on growth performance, intestinal digestion and absorption, and nutrient transporters in broilers. A total of 350 one-day-old male Arbor Acres broilers were randomly divided into seven groups: the control group (broilers receiving normal drinking water), groups P1, P2 and P3 (broilers receiving drinking water with 1% Lactobacillus casei, Lactobacillus acidophilus and Bifidobacterium lactis , respectively) and groups CP1, CP2 and CP3 (broilers receiving drinking water with a 1% compound probiotic mixture in 2:1:1, 1:2:1, 1:1:2 ratios, respectively). The feeding period was divided into two experimental periods: 1∼21 days and 22∼42 days. Compared to those in the control group, the broiler slaughter indexes and average daily feed intakes in the probiotics groups were not significantly different (P > 0.05), but the villus height in the small intestine increased significantly, and the crypt depth decreased significantly (P < 0.05). In the 1- to 21-day, experimental period, the broiler average daily gains in groups CP2 and CP3 were significantly greater than that in the control group. Amylase, lipase, and trypsin activities in the jejunum in groups CP and P3 increased significantly. GLUT2 mRNA expression in the probiotics group was significantly incresaed compared with that in the control group (P < 0.05). In the 22- to 42-day period, the average daily gain in the CP group was significantly greater than that in the control group. Amylase activity in the CP2 group, and lipase and trypsin activities in the CP, P1 and P3 groups increased significantly. The GLUT2 mRNA expression in the CP group increased significantly (P < 0.05). In summary, three probiotics and their interactions improved the digestibility and absorption of nutrients by increasing the activities of digestive enzymes, improving the morphology of the digestive tract, and upregulating the expression of GLUT2 mRNA in the intestinalcell membrane to improve the production performance in broilers.

Nutrient sources differ in the fertilised eggs of two divergent broiler lines selected for meat ultimate pH

The pHu+ and pHu− lines, which were selected based on the ultimate pH (pHu) of the breast muscle, represent a unique model to study the genetic and physiological controls of muscle energy store in relation with meat quality in chicken. Indeed, pHu+ and pHu− chicks show differences in protein and energy metabolism soon after hatching, associated with a different ability to use energy sources in the muscle. The present study aimed to assess the extent to which the nutritional environment of the embryo might contribute to the metabolic differences observed between the two lines at hatching. Just before incubation (E0), the egg yolk of pHu+ exhibited a higher lipid percentage compared to the pHu− line (32.9% vs. 27.7%). Although ¹H-NMR spectroscopy showed clear changes in egg yolk composition between E0 and E10, there was no line effect. In contrast, ¹H-NMR analysis performed on amniotic fluid at embryonic day 10 (E10) clearly discriminated the two lines. The amniotic fluid of pHu+ was richer in leucine, isoleucine, 2-oxoisocaproate, citrate and glucose, while choline and inosine were more abundant in the pHu− line. Our results highlight quantitative and qualitative differences in metabolites and nutrients potentially available to developing embryos, which could contribute to metabolic and developmental differences observed after hatching between the pHu+ and pHu− lines.

Air-classified faba bean protein fraction as a substitute to soybean meal in pelleted and extruded broiler diets

1. The hypothesis that air-classified faba bean protein fraction (FBP) can replace soybean meal (SBM) in pelleted or extruded broiler diets without adverse effect on performance or nutrient digestibility was tested.2. At 17 d of age, male broilers were randomly distriibuted among four dietary treatments consisting of either SBM or FBP (main dietary protein source) and pelleting or extrusion as processing methods. Treatments had 10 replicate pens containing five birds each.3. Compared to SBM, birds fed FBP had significantly lower feed intake, less weight gain and had poorer feed conversion.4. Pellet durability was high (above 92%) for all diets. In pelleted diets, FBP was harder than SBM whereas extruded diets had similar hardness. Pelleting increased water stability compared to extrusion. FBP diets were more water stable than the SBM diets.5. Gizzard content weight was 2.2-fold higher (P = 0.002) for birds given FBP compared to those fed SBM. The weight of the jejunum and ileum with contents was 1.4-fold lower for the FBP diets, and this effect was larger (P < 0.05) for the extruded FBP diet.6. Birds fed FBP diets had significantly higher nitrogen digestibility in the lower jejunum and ileum compared to those given SBM diets, while the starch digestibility coefficient was above 0.980 in all treatments.7. The high nutrient digestibility of FBP diets indicates that the poor performance of the FBP group was due to lower feed intake which was not explained by the differences in pellet durability or hardness. The reduced palatability of the FBP and the longer retention of the FBP diets in the upper gut are more likely to have depressed feed intake.

Dietary supplementation with citrus extract alters the plasma parameters, circulating amino acid profiles and gene expression of small intestinal nutrient transporters in Chinese yellow-feathered broilers

BACKGROUND

This study evaluated the effects of citrus extract (CE) on growth performance, plasma amino acid (AA) profiles, intestinal development and small intestine AA and peptide transporter expression levels in broilers. A total of 540 one-day-old yellow-feathered broilers were fed a basal diet without any antibiotic (control group), or a basal diet containing 10 mg kg^-1 zinc bacitracin (antibiotic group), or a basal diet supplemented with 10 mg kg^-1 CE (CE group). After 63 days of feeding, two broilers per pen were slaughtered to collect tissues for further analysis.

RESULTS

Results showed that CE increased (P < 0.05) the final body weight and average daily gain from day 1 to 63, and decreased (P < 0.05) the feed/gain ratio from day 1 to 63. Dietary CE supplementation increased (P < 0.05) plasma total protein, albumin and glucose concentration, and decreased (P < 0.05) urea concentration. CE supplementation increased (P < 0.05) the villus height in the ileum and the villus height/crypt depth in the jejunum and ileum, but decreased (P < 0.05) the crypt depth in the jejunum and ileum. CE supplementation increased (P < 0.05) most plasma essential AA concentrations. Additionally, CE supplementation upregulated (P < 0.05) ASCT1, b^0,+ AT, B⁰ AT1, EAAT3, rBAT, y⁺ LAT2 and PepT1 expression in the jejunum, and b^0,+ AT, EAAT3, rBAT, y⁺ LAT2, CAT1 and PepT1 in the ileum.

CONCLUSIONS

Collectively, our results indicated that CE supplementation promotes intestinal physiological absorption of AAs by upregulating gene expression of small intestinal key AA and peptide transporters, thereby enhancing the growth performance of broilers. © 2020 Society of Chemical Industry.

Effects of taurine supplementation on productive performance, nutrient digestibility and gene expression of nutrient transporters in quails reared under heat stress

This study was conducted to examine the effects of dietary taurine supplementation on productive performance, nutrient digestibility, antioxidant status, and the gene expression of ileal nutrient transporters in laying quails reared under heat stress (HS). One hundred and eighty laying Japanese quails (Coturnix coturnix japonica) were fed a basal diet or basal diet supplemented with either 2.5 or 5 g of taurine per kg of diet, and reared at either 22 ± 2 °C for 24 h/d (thermoneutral, TN) or 34 ± 2 °C for 8 h/d (HS) for 12 weeks. The quails reared under HS consumed less feed, produced less egg, and had lower dry matter, organic matter and crude protein apparent digestibilities compared with the quails reared under the TN condition (P = 0.001). However, increasing taurine concentrations in the diet improved feed intake and egg production (P = 0.001), but also the apparent digestibilities (P ≤ 0.027) in quails reared under HS. The greater doses (5 g/kg) of taurine resulted in more responses. The quails reared under HS had greater serum and liver MDA concentrations (P = 0.0001) which decreased with dietary taurine supplementations, particularly greater doses. The gene expressions of ileal PEPT1, EAAT3, CAT1, CAT2, SGLT1, SGLT5, GLUT2, and GLUT5 decreased under HS conditions (P = 0.001). However, supplementing taurine, in a dose-dependent fashion, to the diet of quails reared under HS resulted in increases in the gene expressions of the transporters (P < 0.05) except for CAT1. The results of the present work showed that taurine supplementation, particularly with greater doses (5 g/kg), to the diet of laying quails kept under HS acts as alleviating negative effects of HS, resulting in improvements in productive performance and nutrient digestion, and also upregulation of ileal nutrient transporters.

Screening of differentially expressed immune-related genes from spleen of broilers fed with probiotic Bacillus cereus PAS38 based on suppression subtractive hybridization

The aim of this study was to construct the spleen differential genes library of broilers fed with probiotic Bacillus cereus PAS38 by suppression subtractive hybridization (SSH) and screen the immune-related genes. Sixty seven-day-old broilers were randomly divided into two groups. The control group was fed with basal diet, and the treated group was fed with basal diet containing Bacillus cereus PAS38 1×10⁶ CFU/g. Spleen tissues were taken and extracted its total RNA at 42 days old, then SSH was used to construct differential gene library and screen immune-related genes. A total of 119 differentially expressed sequence tags (ESTs) were isolated by SSH and 9 immune-related genes were screened out by Gene ontology analysis. Nine differentially expressed genes were identified by qRT-PCR. JCHAIN, FTH1, P2RX7, TLR7, IGF1R, SMAD7, and SLC7A6 were found to be significantly up-regulated in the treated group. Which was consistent with the results of SSH. These findings imply that probiotic Bacillus cereus PAS38-induced differentially expressed genes in spleen might play an important role in the improvement of immunity for broilers, which provided useful information for further understanding of the molecular mechanism of probiotics responsible to affect the poultry immunity.

Necrotic Enteritis in Broiler Chickens: The Role of Tight Junctions and Mucosal Immune Responses in Alleviating the Effect of the Disease

Necrotic enteritis (NE) continues to present major challenges to the poultry industry, and the etiologic agent Clostridium perfringens is the fourth leading cause of bacterially-induced food- borne illnesses in the US. This study was designed to evaluate the effects of a probiotic during naturally occurring NE. On day of hatch, 1080 Cobb 500 male broilers were randomly allocated to three groups (12 replicate pens/treatment, 30 birds/pen) including 1) negative control (NC): corn-soybean meal diet; 2) positive control (PC): NC + 20 mg virginiamycin/kg diet (0.450 kg Stafac®20/ton); and 3) NC + PrimaLac (1.36 and 0.91 kg/ton from 1-21 and 22-42 days, respectively). One day (d) post placement, all birds were challenged by a commercial live oocyst coccidia vaccine as a predisposing factor to NE. Body weight and feed intake were measured at the onset of NE (d 8) and end of each feeding phase. On d 8, small intestines of two birds/pen were examined for NE lesions, and jejunum samples from one bird were collected for mRNA gene expression analysis of tight junction proteins, cytokines, and nutrient transporters. Data were analyzed using the Jump (JMP) software and significance between treatments identified by LSD (P < 0.05). Compared to NC, supplementation of probiotic reduced d 1-42 mortality; however, PC was the only group with significantly lower mortality. Despite significantly improved feed conversion ratio (FCR) in PC and probiotic groups during d 1-42, average daily gain was only higher in PC (77.69 g/bird) compared with NC (74.99 g/bird). Furthermore, probiotic and PC groups had significantly reduced lesion scores in the duodenum and jejunum compared to NC. Expression of claudin-3 was higher, while expression of zonula occluden-2 tended (P = 0.06) to be higher in probiotic-supplemented birds compared to NC. Moreover, birds fed the probiotic diet had significantly higher expression of IL-10, IL-17, AMPK-α1, and SGLT1 mRNA compared to NC birds. The expression of PepT1 was higher for the probiotic-supplemented group compared to PC. IFN-γ expression was lower in PC compared to NC, while there was no difference between probiotic and NC. There were no differences in gene expression of sIgA, TNF-α, IL-1β, and IL-22 among treatments. Collectively, these data indicate that in a naturally occurring NE model, supplementation of a probiotic helps to improve FCR and reduce lesions, potentially due to the improvements in mRNA expression of tight junctions, cytokines, and nutrient transporters.