Mucin Gene Expression and Mucin Content in the Chicken Intestinal Goblet Cells Are Affected by In Ovo Feeding of Carbohydrates

Effects of maternal dietary threonine concentrations on the productive performance, amino acid profile in plasma and eggs of laying duck breeders, and performance of ducklings one-week post-hatching

This study's aim was to assess how l- threonine (Thr) affected duck breeders' reproductive and productive performance by examining how it affected the amino acid composition of their eggs and plasma and how well ducklings performed a week after hatching. A total of 648 Longyan duck breeders (23 wk) were randomly allotted to six groups with six replicates of 18 ducks. Ducks were fed a basal control diet deficient in Thr and dietary treatments consisted of the basal diet supplemented l-Thr at 0.0 %, 0.07 %, 0.14 %, 0.21 %, 0.28 %, and 0.35 %, constituting total Thr content of 0.41 %, 0.45 %, 0.51 %, 0.60 %, 0.66 %, and 0.72 %, respectively. At 43 wk of age, the addition of l-Thr at a concentration of 0.28 % had superior (P < 0.05) values (P < 0.05) for egg production, egg weight, egg weight, egg mass, feed conversion ratio, yolk weight and its ratio to total egg weigh compared to the control diet, which yielded the lowest values. Over the entire experimental period, feed intake was not affected by dietary treatments. Plasma tyrosine elevated (P = 0.03 and quadratic trend = 0.02) at 0.28 % l-Thr. In addition, plasma citrulline increased linearly (P = 0.06, linear trend P = 0.003) at 0.28 % l-Thr as compared to the control diet. The contents of aspartic acid, Thr, tyrosine, and proline in egg yolk exhibited a linear increase (P < 0.05) corresponding to increased l- Thr levels. In addition, the contents of serine and cysteine were significantly enhanced at 0.35 % l-Thr, whereas the content of glycine experienced a decrease (P < 0.05) as l- Thr levels increased. The amino acid profile in the egg albumen demonstrated a reduction at 0.28 % and 0.35 % l-Thr, whereas feeding l-Thr at 0.21 % led to an increase in proline contents (P = 0.03, quadratic trend P = 0.002). The addition of l-Thr at a concentration of 0.28 % recorded the heaviest body weight of ducklings after hatching, while the control or 0.07 % Thr group recorded the lowest values. These findings suggest that l-Thr supplementation at 0.28 % (constituting total Thr content of 0.66 %) is an effective nutritional strategy to optimize the performance of duck breeders and the quality of their offspring, providing valuable insights for dietary formulations in poultry production and emphasizing the importance of balanced amino acid nutrition for maximizing breeder performance and offspring quality.

Exposure of broiler chickens to deoxynivalenol and Campylobacter jejuni induces substantial changes in intestinal gene expression

The mycotoxin deoxynivalenol (DON) is of high importance among feed contaminants because of its frequent occurrence in toxicologically relevant concentrations worldwide. Cereal crops, the main component of chicken diet, are commonly contaminated with DON, resulting in frequent exposure of chickens to DON. Likewise, Campylobacter (C.), a pathogen of major public and animal health concern, is frequently found in chicken flocks and poses a threat to the One Health approach. Campylobacter colonizes the gastrointestinal (GI) tract of poultry with a high bacterial load in the caeca. However, the mechanism of C. jejuni colonization in chickens is still not understood albeit it is well known that C. jejuni resides primarily in the mucosal layer of the chicken intestine. Therefore, in the actual study we focused on the effect of exposure to DON and/or C. jejuni on expression profiles of intestinal mucins (MUC1, MUC2), β-defensins (Gallinacin (GAL) 10, 12), cytokines (Toll-like receptor 2 (TLR2), Interleukin (IL) 6, 8, Interferon-γ (IFN)-γ), inducible nitric oxide synthase 2 (iNOS2), as well as selected tight junction proteins (Claudin 5 (CLDN5), Occludin (OCLN), and zonula occludens-1 (ZO1) via RT-qPCR. For this, a total of 150 one-day-old Ross 308 broiler chickens were randomly allocated to six different groups (n = 25 with 5 replicates/group) and were fed for 5 weeks with either contaminated diets (5 or 10 mg DON/kg feed) or basal diets (control). Following oral infection of birds with C. jejuni NCTC 12744 at 14 days of age, several changes in gene expression patterns were demonstrated. A significant (P ≤ 0.05) downregulation of MUC2 mRNA expression was observed in birds fed DON5 and DON10 diet, as well as in birds co-exposed to DON5 and C. jejuni at 7 dpi. Furthermore, at 14 dpi, MUC2 mRNA expression was significantly (P ≤ 0.05) downregulated in birds fed DON (5 mg and 10 mg/kg diet) with and without C. jejuni and in birds infected solely with C. jejuni. The actual study also demonstrated that co-exposure of broiler chickens to DON and C. jejuni resulted in a decreased barrier function via downregulation of OCLD mRNA expression. In addition, Campylobacter infection induced an increased expression of the antimicrobial peptide GAL12 and the IL8 gene, indicating that C. jejuni can initiate an immune response in the chicken gut in a proinflammatory manner. Similarly, DON with and without C. jejuni induced upregulation of GAL10 and GAL12 mRNA expression at 7 dpi. Moreover, no change in iNOS2 mRNA expression was observed in both the jejunum and the cecum at either 7 dpi or 14 dpi, suggesting unchanged NO production during exposure/infection. In conclusion, we confirmed that DON contamination corresponding to the currently applicable EU guidance value of 5 mg DON/kg feed affects the intestinal gene expression profiles of broilers, mainly in a dose-independent manner. Furthermore, DON exposure interacted synergistically with C. jejuni challenge regarding mucins, innate immunity gene expression in either the jejunum or the cecum, suggesting immunomodulatory activity of both foodborne agents (DON and C. jejuni).

Effects of Formula Product Injection on Hatching Parameters, Small Intestinal Development and Ileum Histology in Breeder Chicken Eggs

BACKGROUND AND OBJECTIVE

This study aimed to determine the effects of in ovo formula product injection on hatching parameters, chick quality, small intestinal development and ileum histology of breeder hen eggs.

METHODS

A total of 400 fertilised eggs were obtained from the Atak-S parent flock at 42 weeks of age for the experiment. The experiment was designed in two groups: a control group (C), in which no injection was performed, and the other group in which a solution containing formula products at concentrations of 1.25% (F1), 2.5% (F2) and 5% (F3) was injected into 0.5 mL/egg air sac. The hatching rate, embryonic mortality and discard chick rate were examined at the end of the trial.

RESULTS

The best result of the hatching rate was found in the Group F2, while there was no difference between the control and Group F1 regarding these parameters. The weight and length of the quality chicks were promoted in the Group F1. In Group F3, the injection of the formula product at a rate of 5% had a negative effect on parameters such as hatchability, embryonic mortality, chick length, Pasgar score and yolk sac weight compared to the other groups. Otherwise, in Group F2, there was a significant increase in villus height, crypt depth and lamina muscularis mucosa thickness compared to the other groups (p < 0.01).

CONCLUSIONS

As a result, it has been concluded that the appropriate rates for the formula product application on chicks are 1.25% and 2.5%, considering the positive effects of the 1.25% and 2.5% rates and the negative effects of the 5% rate.

Effects of in-ovo injection of Yu ping feng polysaccharides on growth performance, intestinal development, and immunity in broiler chickens

This study aimed to investigate the effects of the in-ovo injection of Yu Ping Feng polysaccharides (YPF) on the immunological development, hatchability, growth performance, intestinal tissue development, intestinal IgA+ cell distribution, and intestinal secretory IgA (SIgA) production in broiler chicken. Herein, 800 chicken embryos were randomly divided into Astragalus polysaccharide (APS), Atractylodes macrocephala polysaccharide (ATR), YPF, and normal saline (control) injection groups-polysaccharide injection, 0.5 mL of 4 mg/mL polysaccharide; normal saline injection, 0.5 mL. The related indexes of hatched chicks were detected, and there were 5 repeats in each group. Compared with the other three groups, the in-ovo YPF injection did not affect the hatching rate of chicken embryos; however, the initial body weight of hatchlings significantly increased and the feed conversion ratio decreased. Additionally, at each time point, the intestinal villus height (VH) of the chicks in the YPF group increased, whereas no notable difference was observed in the crypt depth (CD), resulting in a higher VH/CD ratio. Furthermore, the YPF group exhibited a statistically significant increase in intestinal IgA+ cell count and flushing fluid SIgA level throughout various time periods compared with those in the other three groups. Additionally, the expression of intestinal mucosal immune cytokines, including interleukin (IL)-2, IL-4, IL-6, and interferon-γ, were markedly increased in the duodenum and ileum of the YPF group. Moreover, the analysis of immune development revealed that their serum levels in the polysaccharide-injected groups were also increased, with the YPF groups exhibiting superior performance than the APS and ATR groups and encouraging the development of T and B lymphocytes in the spleen and peripheral blood mononuclear cells. Altogether, the findings of this study demonstrate that the in-ovo injection of YPF can improve the growth performance, intestinal tissue development, and immune system of the broiler chicks.

Ontogeny and function of the intestinal epithelial and innate immune cells during early development of chicks: to explore in ovo immunomodulatory nutrition

Intestinal epithelial cells (IECs) and innate immune cells in the gastrointestinal tract (GIT) of chickens play crucial roles in pathogens defense and maintaining gut health. However, their effectiveness influenced with their developmental and functional stages during pre and post hatch periods of chick. During embryonic development, differentiation and migration of these innate immune systems are tightly regulated by diverse cellular and molecular factors. The maturation and functionality of IECs are histologically evident starting embryonic day (ED) 14. Moreover, the innate immun cells, such as dendritic cells (DCs), macrophages, natural killer (NK) cells, and gamma-delta (γδ) T cells have showed developmental expression varation, while most identified by the 3rd days of incubation and capable of responsing to their cognate ligands of pathogens by ED 17, it may not efficient during posthatch period. In modern poultry production, in ovo feeding of bioactive substances is a topic of interest to maximize the protection capability of hatched chicks by enhancing improvement on the development of innate immune systems. However, their actions and effects on each distinct innate immune involved response are inconsistent and not clearly understood. Thus, summarizing the ontogeny and function of IECs, innate immunity systems, and interaction mechanisms of in ovo feeding of bioactive substances could provide baseline information for designing targeted in ovo feeding interventions to modulate cell waise specific innate immune systems.

Limosilactobacillus reuteri B1/1 modulated the intestinal immune response in preventing Salmonella Enteritidis PT4 infection in a chicken ileal explant model

In this study, we observed the effect of the newly isolated probiotic strain Limosilactobacillus reuteri B1/1 on the relative gene expression of selected cytokines (interleukin-15, transforming growth factor-β4), tight junction proteins (E-cadherin, occludin), biomarker active intestinal stem cells - LGR5 (leucine-rich repeat containing G protein-coupled receptor), markers of mucosal intestinal immunity (mucin-2, immunoglobulin A), as well as the creation of a new biomarker of inflammation in the intestine - calprotectin on an ex vivo model of chicken ileal explant in the prevention of Salmonella Enteritidis PT4 infection. The ability of L. reuteri B1/1 to effectively modulate the mucosal immune response under pretreatment conditions in S. Enteritidis PT4 infection in a chicken ileal explant model was confirmed. In addition, our obtained results point to the fact that the new chicken ileum explant model could be a suitable model to investigate or test the influence of natural substances such as probiotic bacteria in the interaction with the intestine as well as pathogenic microorganisms. In addition, the results of our study may contribute to a deeper understanding of the action of newly isolated probiotic bacteria at the intestinal level using ex vivo models such as chicken ileum explant, which are able to mimic in vivo conditions sufficiently.

Descriptive embryological insights of the colorectum of quail embryos with concern to its functional morphology

BACKGROUND

Quail is an interesting emerging bird species gaining attention in developmental embryology research due to its small size, quick lifespan, and fast growth rate. These characteristics make quail an ideal model for examining the development of the gastrointestinal tract. Consequently, the embryonic development of the colorectum was conducted to provide a comprehensive understanding of its functions in digestion, absorption, and immunity.

METHODOLOGY

The morphological anatomy and microscopical structure of the colorectal wall of 74 embryos were studied using light and scanning electron microscopy (SEM). Histologically, the embryos were collected and dissected to extract the intestine. The samples were then fixed in 10% neutral buffer formalin for a minimum of 24 h, and in 2.5% glutaraldehyde buffer formalin for semithin processing and scanning electron microscopy.

RESULTS

The wall of the embryonic colorectum on the hatching day consisted of three layers; mucosa, muscularis externa, and serosa. Mucosa was a simple layer of columnar enterocytes interspersed with goblet cells that appeared as cub-like shaped cells. Additionally, two ganglionic plexuses were also developed in the colorectal wall; Auerbach plexus (among the colorectal tunica muscularis) and Meissner plexus (submucosal plexus).

CONCLUSION

The morphological characteristics of the quail colorectum at different ages were closely related to its functional features.

Exploration of Some Nutrient Absorption-Related Genes and Intestinal Histology in Japanese Quails (Coturnix japonica) Throughout Their Productive Lifespan

BACKGROUND

Quail is an efficient poultry species known for many years, and its productivity is highly affected by gastrointestinal function, health, digestion and commensal bacteria. Specific histological parameters and nutrient absorption-related genes could be used to study intestinal functionality and efficiency.

OBJECTIVES

This study aimed to evaluate the mRNA abundance of nutrient absorption-related genes and intestinal histology changes in laying Japanese quail during productive lifespan.

METHODS

A total of 135 quails from a commercial flock at different egg production periods (early production [EP, 6 weeks of age], pick production [PP, 21 weeks of age] and post pick production [PPP, 40 weeks of age]) were randomly selected (n = 45/group) and kept for 6 weeks. Production performance was evaluated during last 2 weeks of the experimental period, and tissue samples were taken from the duodenum, jejunum and ileum for histological analysis and mRNA abundance purposes at the end of the experiment. The mRNA abundance of the CALB1, SGLT1, SGLT5, EAAT3 and NaPi-IIb genes were compared among groups.

RESULTS

Production period did not affect the eggshell thickness, goblet cell number and mRNA abundance of CALB1, EAAT3 and NaPi-IIb (p > 0.05). The PPP quails had the highest egg weight and FCR compared to EP and PP quails (p < 0.001). Egg production and egg mass of the EP and PP quails were higher than those of PPP quails (p < 0.001). Moreover, EP quails had the highest villus height (VH)/crypt depth (CD) ratio in the duodenum and jejunum and the lowest VH:CD in the ileum compared with the PPP quails (p < 0.01). The lowest SGLT1 mRNA abundance was noted in the PP quails, whereas EP quails had the highest SGLT5 mRNA abundance (p < 0.05).

CONCLUSIONS

In conclusion, although histology parameter changes were in-line with the lowest performance observed in the PPP quails, the current results failed to show a relationship between mRNA abundance changes and production performance attributes at different productive lifespans.

Evaluation the effect of dietary vitamin E, sesamin and thymoquinone bioactive compounds on immunological response, intestinal traits and MUC-2 gene expression in broiler Japanese quails (Coturnix japonica)

The current study was performed to determine the effect of dietary vitamin E, sesamin and thymoquinone bioactive lignans derived from sesame and black seed on immunological response, intestinal traits and Mucin2 gene expression in broiler quails. Three hundred and fifty (one days-old) quails were allotted to seven dietary treatments with five replicates as an experimental randomized design study. Treatments were basal diet as a control, control +100 and +200 mg of vitamin E, sesamin and thymoquinone per each kg of diet respectively. At 35 d of age, two quails from each pen were chosen, weighted, slaughtered, eviscerated and lymphoid organ relative weights were measured. Anti-body titers against Newcastle disease (ND), Sheep red blood cell (SRBC), and infectious bronchitis virus (IBV) and Avian influenza (AI) vaccination were determined. The serum activities of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and serum antioxidant activates such as superoxide dismutase (SOD),glutathione peroxidase(GPX), catalase (CAT) and total antioxidant capacity (TAC) were examined. The cell mediated immunity by dinitrochlorobenzene (DNCB) and phytohemagglutinin (PHA) challenges were assessed. The microflora populations of ileum, morphological traits of jejunum and mucin2 gene expression were analyzed. Data showed that the lymphoid organ (thymus, spleen and Bursa) relative weights and antibody titer against HI, AI, SRBC and IB vaccination were increased compared to the control (p ≤ 0.05). Serum activities of ALP, ALT and AST were decreased under influences of dietary treatments (p ≤ 0.05). The serum antioxidant activates of GPX,SOD,CAT and TAC were increased and Increasing in mean skin thickness after DNCB challenge and decrease wing web swelling response to PHA mitojen injection were observed (p ≤ 0.05). Salmonella enterica, E-coli and Coliforms colonies were decrease and Lactobacillus colonies increased instead (p ≤ 0.05). The villus height and surface, crypt depth and goblet cells density were increased compared to the control (p ≤ 0.05). The expression of MUC2 gene increased under influnces of vitamin E, sesamin and thymoquinone supplemented diets (p ≤ 0.05).

The effect of Limosilactobacillus fermentum 2i3 and 0.6% addition of humic substances on production parameters and the immune system of broilers

The widespread use of antibiotics in the poultry industry as growth promoters has led to the emergence of bacterial resistance, which poses a significant health risk to humans and animals. Substances of natural origin, such as probiotic bacteria and humic substances, can be a promising solution. The aim of this experiment was to study the effect of the administration of a probiotic strain of Limosilactobacillus fermentum 2i3 and/or a new formula of humic substances specifically designed for detoxification on the production parameters, including gene expression of myogenic growth factors and selected parameters of the immune response. We found that production parameters such as feed conversion ratio and weekly weight gain, as well as gene expression of mucin-2 and immunoglobulin A, were positively influenced mainly by the administration of L. fermentum 2i3. Similarly, the percentage of active phagocytes and their absorption capacity as well as the proportions of CD8+ and CD4+CD8+ T-lymphocyte subpopulations were significantly increased. The addition of humic substances, either alone or in combination with probiotics, significantly reduced the aforementioned parameters compared to the control. On the other hand, the relative gene expression for all myogenic growth factors was the highest in the humic group alone. Based on the results obtained, we can confirm the immunostimulating effect of L. fermentum 2i3 administered in drinking water, which also had an impact on important production parameters of broiler meat. On the other hand, in the combined group there was no expected potentiation of the positive effects on the observed parameters.

Apparent ileal amino acid digestibility, gut morphometrics, and gene expression of peptide and amino acid transporters in broiler chickens fed low-crude-protein diets supplemented with crystalline amino acids with soybean meal, canola meal, or corn DDGS as protein feedstuffs

BACKGROUND

We investigated the impact of using canola meal (CM) or corn distillers dried grain soluble (cDDGS) in place of soybean meal (SBM) in low-crude-protein diets supplemented with amino acids (AA) on AA digestibility, gut morphometrics, and AA transporter genes in broiler chicken. On day 0, 540 Cobb 500 male broilers were allocated to six diets in 36-floor pens. The positive control (PC) was a corn-SBM diet with adequate crude protein (CP). The CP level of negative control (NC) was decreased by 45 and 40 g kg-1 relative to PC for grower and finisher phases, respectively. The subsequent two diets had the same CP levels as NC but with cDDGS added at 50 or 125 g kg-1. The last two diets had the same CP as NC but with CM added at 50 or 100 g kg-1.

RESULTS

Dietary CP reduction in corn-SBM diets increased (P < 0.05) the digestibility of Lys (88.5%), Met (90.7%), Thr (77.4%), Cys (80.7%), and Gly (84.7%). Increasing levels of cDDGS linearly decreased (P < 0.05) the digestibility of Asp, Cys, Glu, and Ser, whereas increasing CM level linearly decreased (P < 0.05) the digestibility of Cys, Pro, and Ser. The CP reduction in corn-SBM diets produced downward expression of peptide transporter1 and decreased (P < 0.05) absolute pancreas and ileum weight and length of jejunum and ileum.

CONCLUSIONS

Partial replacement of SBM with alternative protein feedstuffs (cDDGS or CM) in low-CP diets had minimal effects on AA digestibility and mRNA levels of peptides and AA transporters. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Factors influencing the development of gastrointestinal tract and nutrient transporters' function during the embryonic life of chickens-A review

Intestinal morphology and regulation of nutrient transportation genes during the embryonic and early life of chicks influence their body weight and feed conversion ratio through the growing period. The intestine development can be monitored by measuring villus morphology and enzymatic activity and determining the expression of nutrient transporters genes. With the increasing importance of gut development and health in broiler production, considerable research has been directed towards factors affecting intestine development. Thus, this article reviews (1) intestinal development during embryogenesis, and (2) maternal factors, in ovo administration, and incubation conditions that influence intestinal development during embryogenesis. Conclusively, (1) chicks from heavier eggs may have a better-developed intestine than chicks from younger ones, (2) in ovo supplementation with amino acids, minerals, vitamins or a combination of several probiotics and prebiotics stimulates intestine development and increases the expression of intestine mucosal-related genes and (3) the long storage period, improper incubation temperature and imbalanced ventilation can negatively influence intestinal morphology and nutrient transporters gene expression. Finally, understanding the intestine development during embryonic life will enable us to enhance the productivity of broilers.

Improvement in growth performance and digestive function from amniotic injections of N-acetylglutamate in broiler chickens

BACKGROUND

N-acetylglutamate (NAG) is the initial and essectial substrate in the process of de novo arginine synthesis, plays an important role in intestinal development. The aim of this study was to determine the effects of in ovo feeding of NAG, 1.5 mg/egg at 17.5 days of incubation (DOI) via amnion, on hatching performance, early intestinal histomorphometry, jejunal barrier, digestive function, and growth performance of broiler chickens between 1 and 14 days of age.

RESULTS

Amniotic injection of NAG had no significant effect on hatching characteristics compared with the non-injected control group (NC group). Birds in the NAG solution-injected group (NAG group) exhibited lower average daily feed intake and better feed efficiency during a period of 1-14 days. In comparison with the NC group, the NAG group had decreased crypt depth (CD) in the ileum and increased villus height (VH) / CD in the jejunum at 7 days, and decreased CD in duodenum and significantly increased VH in the jejunum at 14 days. However, the effects of in ovo supplementation with NAG on the density of goblet cells, and gene expression of mucin 2 and alkaline phosphatase were not significant. Chicks in the NAG group had a significantly higher mRNA expression level of trypsin and maltase in jejunum at 7 days than the NC group but not at 14 days.

CONCLUSION

Amniotic injections of NAG (1.5 mg/egg) at 17.5 DOI could improve early growth performance of broilers during 1-14 days after hatching by accelerating the development of the intestine and enhancing jejunal digestive function. © 2023 Society of Chemical Industry.

High amylose to amylopectin ratios in nitrogen-free diets decrease the ileal endogenous amino acid losses of broiler chickens

This study explored the variation of ileal endogenous amino acid (IEAA) losses and its influencing factors in chickens offered nitrogen-free diets (NFD) containing different ratios of amylose to amylopectin (AM/AP). A total of 252 broiler chickens at 28 d old were randomly allocated into 7 treatment groups for a 3-d trial. The dietary treatments included a basal diet (control), a NFD containing corn starch (CS), and 5 NFD with AM/AP ratios of 0.20, 0.40, 0.60, 0.80, and 1.00, respectively. As the AM/AP ratio increased, the IEAA losses of all AAs, starch digestibility and maltase activity linearly decreased (P < 0.05), but the DM digestibility linearly and quadratically decreased (P < 0.05). Compared with the control, the NFD increased the number of goblet cells and its regulatory genes mucin-2 and krüppel-like factor 4 (KLF-4) while decreasing serum glucagon and thyroxine concentrations, ileal villus height, and crypt depth (P < 0.05). Additionally, NFD with lower AM/AP ratios (0.20 and 0.40) decreased the ileal microbiota species richness (P < 0.05). In all NFD groups, the number of Proteobacteria increased whereas the abundance of Firmicutes dropped (P < 0.05). However, the broilers in the AM/AP 0.60 group were closer to the digestive physiological state of chickens fed the control diet, with no significant change in maltase activity and mucin-2 expression (P < 0.05). In conclusion, increasing AM/AP ratio in a NFD decreased the IEAA losses and the apparent ileal digestibility of starch but inevitably resulted in malnutrition and disruption of gut microbiota homeostasis. This study recommends AM/AP in NFD at 0.60 to measure IEAA of broiler chickens.

Ameliorative avian gut environment and bird productivity through the application of safe antibiotics alternatives: a comprehensive review

The avian digestive tract is an important system for converting ingested food into the nutrients their bodies need for maintenance, growth, and reproduction (meat, table eggs, and fertile eggs). Therefore, preserving digestive system integrity is crucial to bird health and productivity. As an alternative to antibiotics, the world has recently turned to the use of natural products to enhance avian development, intestinal health, and production. Therefore, the primary goal of this review is to explain the various characteristics of the avian digestive tract and how to enhance its performance with natural, safe feed additives such as exogenous enzymes, organic acids, photogenic products, amino acids, prebiotics, probiotics, synbiotics, and herbal extracts. In conclusion, the composition of the gut microbiome can be influenced by a number of circumstances, and this has important consequences for the health and productivity of birds. To better understand the connection between pathogens, the variety of therapies available, and the microbiome of the gut, additional research needs to be carried out.

Dietary muramidase increases ileal amino acid digestibility of wheat and corn-based broiler diets without affecting endogenous amino acid losses

The objective of these studies was to evaluate the impact of dietary muramidase (MUR) on endogenous amino acids (AA) losses and digestibility of nutrients in wheat and corn-based broiler diets. In experiment 1, the effect of dietary MUR on the flow of endogenous AA (EAA) at the jejunum and terminal ileum of broilers were assessed using either the nitrogen (N) free diet method (NFD) or the highly digestible protein diet method (HDP; 100 g casein/kg diet). Sialic acid and muramic acid concentrations were measured in the jejunal content. In experiment 2, a 2x2x2 factorial arrangement of treatments with 2 base grains (wheat or corn), with low or high metabolizable energy (ME) levels, and without or with MUR supplementation was implemented. All diets contained phytase, xylanase, and cellulase. Apparent ileal digestibility (AID) of dry matter (DM), protein (CP), amino acids (AA), crude fat, and energy, as well as the apparent total tract metabolizability (ATTM) of DM, CP, and gross energy (GE) were determined. The standardized ileal digestibility (SID) of AA was obtained by correcting AID values for basal ileal EAA obtained from chicks fed with NFD or HDP in experiment 1, jejunal EAA flow of all AA was higher (P < 0.001) compared to the ileum, but this effect was method dependent. Jejunal, but not ileal, EAA flow measured with HDP was higher compared to NFD, as well as sialic acid (P < 0.001) and muramic acid (P < 0.004) concentrations. Muramidase inclusion had no effect on basal EAA flow, independently of the segment and the method used. In experiment 2, dietary MUR supplementation increased the AID of CP (P < 0.05), all AA, and tended (P = 0.07) to increase the AID of GE, independently of the cereal type used. However, ATTM of DM and GE, but not CP, increased with MUR inclusion compared with the control treatments, especially in wheat and low ME diets (P < 0.05). In conclusion, MUR supplementation improved AID of CP and AA without affecting EAA losses and increases energy utilization.

Anatomical, histochemical, and immunohistochemical observations on the gastrointestinal tract of Gallinula chloropus (Aves: Rallidae)

Background

Gallinula chloropus (Linnaeus, 1758) is a wild aquatic omnivorous bird characterized by a marked resistance to harsh environmental conditions and a worldwide distribution. In this study, anatomical, morphometrical, histochemical, and immunohistochemical techniques were employed to study the structure of the gastrointestinal tract of Gallinula chloropus.

Results

The esophagus appeared tubular with no distinct crop. Both superficial (SPG) and deep (DPG) proventricular glands were present. The DPG filled about two-thirds of the total wall thickness. Histochemically, the mucosubstances revealed mixed alcian blue-PAS positive reactions. They were mainly localized in the acini of the esophageal glands and SPG, gastric surface epithelium, duct system of DPG, and intestinal goblet cells. The highest number of goblet cells per every 1 mm2 of the intestinal mucosa was seen within the ileum and rectum, 2555 ± 468 and 2607 ± 653 respectively. Notably, glucagon immunoreactive (IR) cells were abundant in the mucosa of the small and large intestines and the proventriculus, while somatostatin IR cells were concentrated within the acini of the DPG. IR cells for the mitosis marker phospho-histone H3 (PHH3) were highest within the entire intestinal crypts and mucosa-associated lymphoid tissues (MALT). In contrast, cells IR for the apoptosis marker C.CASP3 were remarkable in epithelial cells at the tips of intestinal villi and in MALT, reflecting the dynamic nature of the latter mentioned structures.

Conclusions

The findings of the present study advance our knowledge of the gross and microscopic anatomy of the gastrointestinal tract in wild birds and could help to enhance the productivity of Aves via improving gut health.

Expression of nutrient transporter genes in response to dietary rice gluten meal and protease enzyme supplementation and the consequent effects on growth, nutrient digestibility, immunity and jejunum histomorphometry in chicken

The objective of this study was to investigate the effects of feeding rice gluten meal (RGM) as an alternative protein source along with protease enzyme supplementation on growth performance, expression of nutrient transporter genes, nutrient digestibility, immune response and gut histomorphometry of broiler chicken. Proximate analysis of RGM revealed 923 g dry matter (DM), 500 g crude protein (CP), 69.2 g ether extract, 94.7 g crude fiber, 215.4 g nitrogen-free extract, 43.7 g ash, 6.20 g calcium, 7.80 g total phosphorus, 18.99 MJ gross energy and 12.68 MJ metabolizable energy per kg diet. Significant upregulation of nutrient transporter genes (PepT1, EAAT3 and mucin) and better growth performance was observed in the birds fed control diet which was statistically similar to the birds fed 150 g RGM compared to birds fed higher RGM levels. Histomorphometry of jejunum, nutrient digestibility, and immune response of birds did not reveal any significant effect of RGM or protease enzyme supplementation. However, the inclusion of RGM up to 150 g/kg diet resulted in significant decline of feed cost/kg live weight gain, dressed meat yield and eviscerated meat yield by 13.13%, 12.99% and 13.36%, respectively compared to control. Thus, it was concluded that the inclusion of 150 g RGM/kg diet in broiler chicken ration has no adverse effects on the growth pattern of birds and can be used for least-cost feed formulation for chicken.

Potential Probiotics Role in Excluding Antibiotic Resistance

Background. Antibiotic supplementation in feed has been continued for the previous 60 years as therapeutic use. They can improve the growth performance and feed efficiency in the chicken flock. A favorable production scenario could favor intestinal microbiota interacting with antibiotic growth promoters and alter the gut bacterial composition. Antibiotic growth promoters did not show any beneficial effect on intestinal microbes. Scope and Approach. Suitable and direct influence of growth promoters are owed to antimicrobial activities that reduce the conflict between host and intestinal microbes. Unnecessary use of antibiotics leads to resistance in microbes, and moreover, the genes can relocate to microbes including Campylobacter and Salmonella, resulting in a great risk of food poisoning. Key Findings and Conclusions. This is a reason to find alternative dietary supplements that can facilitate production, growth performance, favorable pH, and modulate gut microbial function. Therefore, this review focus on different nutritional components and immune genes used in the poultry industry to replace antibiotics, their influence on the intestinal microbiota, and how to facilitate intestinal immunity to overcome antibiotic resistance in chicken.

Supplementing the early diet of broilers with soy protein concentrate can improve intestinal development and enhance short-chain fatty acid-producing microbes and short-chain fatty acids, especially butyric acid

Background

Research on nutrition in early-life commonly focuses on the maturation of the intestine because the intestinal system is crucial for ensuring continued growth. To explore the importance of early nutrition regulation in animals, soy protein concentrate (SPC) was added to the early diet of broilers to investigate its effects on amino acid digestibility, intestinal development, especially intestinal microorganisms, and broiler metabolites. A total of 192 one-day-old Arbor Acres (AA) male broilers were randomly assigned to two experimental treatments with 8 replicates of 12 birds. The control group was fed a basal diet (control), and the treatment group was fed a basal diet supplemented with 12% SPC (SPC12) during the first 10 d (starter phase). From d 11 to 21 (grower phase) and d 22 to 42 (finisher phase), a basal diet was fed to both treatment groups.

Results

SPC reduced the pH value and acid-binding capacity of the starter diet (P < 0.05, d 10); SPC in the early diet enhanced the gizzard weight (P < 0.05, d 10 and d 42) and the ileum weight (P < 0.05, d 10) and decreased the weight and length of the jejunum (P < 0.05, d 10) and the relative length of the duodenum and jejunum (P < 0.05, d 10). At the same time, SPC enhanced villus height (P < 0.05, d 10) and muscle thickness in the jejunum and ileum (P < 0.05, d 10) and increased the number of goblet cells in the duodenum (P < 0.05, d 10). Meanwhile, SPC increased the Chao1 index and the ACE index (P < 0.05, d 10) and altered the composition of caecal microflora at d 10. SPC also increased the relative abundance of Alistipes, Anaerotruncus, Erysipelatoclostridium, Intestinimonas and Flavonifractor bacteria (P < 0.05, d 10). At the same time, the concentrations of caecal butyric acid and total short-chain fatty acids (SCFAs) were also increased in the SPC12 group (P < 0.05, d 10).

Conclusions

In summary, the results showed that supplementing the starter diet of broilers with SPC has a significant effect on the early development of the intestine and the microflora.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s40104-022-00749-5.

Chicken Incubation Conditions: Role in Embryo Development, Physiology and Adaptation to the Post-Hatch Environment

The chicken hatching egg is a self-contained life-supporting system for the developing embryo. However, the post-hatch performance of birds depends on several factors, including the breeder management and age, egg storage conditions and duration before incubation, and the incubation conditions. Studies have determined the effect of incubation factors on chick post-hatch growth potential. Therefore, chick physical quality at hatch is receiving increasing attention. Indeed, although incubation temperature, humidity, turning and ventilation are widely investigated, the effects of several variables such as exposure of the embryo to high or low levels, time of exposure, the amplitude of variations and stage exposures on embryo development and post-hatch performance remain poorly understood. This review paper focuses on chick quality and post-hatch performance as affected by incubation conditions. Also, chick physical quality parameters are discussed in the context of the parameters for determining chick quality and the factors that may affect it. These include incubation factors such as relative humidity, temperature, turning requirements, ventilation, in ovo feeding and delay in feed access. All these factors affect chick embryo physiology and development trajectory and consequently the quality of the hatched chicks and post-hatch performance. The potential application of adapted incubation conditions for improvement of post-hatch performance up to slaughter age is also discussed. It is concluded that incubation conditions affect embryo parameters and consequently post-hatch growth differentially according to exposure time and stage of exposure. Therefore, classical physical conditions are required to improve hatchability, chick quality and post-hatch growth.

Supplementation of live yeast culture modulates intestinal health, immune responses, and microbiota diversity in broiler chickens

The present study investigated the effects of live yeast cultures (LYC) on growth performance, gut health indicators, and immune responses in broiler chickens. A total of 720 mixed-sex broilers (40 birds/pen; 9 replicates/treatment) were randomly allocated to two dietary treatments: (1) a basal diet based on corn-soybean meal (CON) and (2) CON with 1 g/kg LYC. At 35 d of age, one bird per replicate pen was chosen for biopsy. LYC group tended (P < 0.10) to increase average daily gain during the grower phase compared with CON group. Broilers fed LYC diet had increased (P = 0.046) duodenal villus height and area but reduced (P = 0.003) duodenal crypt depth compared with those fed CON diet. Birds fed LYC diet presented alleviated (P < 0.05) serum TNF-α, IL-1β, and IL-6 levels compared with those fed CON diet. Further, birds fed LYC diet exhibited upregulated (P < 0.05) ileal tight junction-related proteins and pro-inflammatory cytokines in the ileal tissue compared with those fed CON diet. Inverse Simpson's diversity (P = 0.038) revealed that birds fed CON diet had a more diverse microbiota community in the ileal digesta, compared with those fed LYC diet, while no significant difference between the treatments on Chao1 and Shannon's indices was observed. Based on the weighted UniFrac distance, the PCoA showed that microbiota in the ileal digesta of the LYC group was different from that of the CON group. LYC group increased the abundance of the phyla Firmicutes and genera Lactobacillus, Prevotella, and Enterococcus compared with CON group. The present study demonstrated that supplemental LYC as a feed additive provide supportive effects on enhancing gut functionality by improving the upper intestinal morphology and gut integrity, and modulating the immune system and microbiota communities of birds.

The Effect of Enterococcus faecium AL41 on the Acute Phase Proteins and Selected Mucosal Immune Molecules in Broiler Chickens

Probiotic bacteria, including the Enterococcus faecium strain, can improve intestinal mucosal health by several mechanisms, including modulation of the immune response, as well as by improving the protective function of the epithelial barrier. In this study, we tested the effect of Enterococcus faecium AL41 on the acute phase proteins response (blood), gene expression of selected molecules of mucosal immunity (immunoglobulin A, mucin-2, insulin-like growth factor 2) and mucus production (all parts of the small intestine) in broilers. Eighty broiler chicks were divided into two groups: a control and E. faecium AL41 (birds were inoculated with AL41 for 7 days) group. The whole experiment lasted 11 days. Our results revealed that the administration of E. faecium AL41 had no substantial effect on the concentrations of acute phase proteins, but we recorded a significant increase in β- and γ-globulin fractions at the end of the experiment, which may indicate an improvement in the immune status. A significant prolonged stimulatory effect of E. faecium AL41 on the relative expression of molecules (immunoglobulin A, mucin-2) as well as on the dynamic of mucus production in the chicken intestine was observed. In addition, AL41 significantly reduced the total number of enterococci in the cecum and faeces.

Immune Response and Fatty Acid Profile of Eggs from Laying Hens Fed Fermented Feed Rich in Polyunsaturated Fatty Acids

Western diets are dominated by the consumption of chemically modified foods, characterized by a deficiency of n-3 polyunsaturated fatty acids (PUFAs). Lack of n-3 PUFAs is also present in livestock feed, which negatively affects livestock health, including immune response, and results in a low content of n-3 PUFAs in animal products. The goal of this experiment was to study the effect of the addition of feed containing PUFAs produced by the fungus Mortierella alpina on immune parameters (IgA, MUC-2, IGF-2, phagocytoses and selected lymphocyte subsets) and the composition of the intestinal microbiota of hens and egg fatty acids profile. Hens were divided into groups (control, F10—supplemented with 10% of fermented feed, F15—supplemented with 15% of fermented feed). The relative expression of all genes was markedly upregulated, mainly in the F15 group. Likewise, in F15, a significant increase in both phagocytes engulfing capacity and the level of oxidative burst was observed. Neither CD T cell subpopulations nor the CD4/CD8 ratio were significantly affected. A significant increase in small intestinal enterobacteria was observed in the F15. The fatty acid profile of eggs in both experimental groups showed an increased proportion of n-3 PUFAs and decreased n-6/n-3 PUFAs ratio. The results of this work show that the addition of 15% omega-3 acids enriched fermented feed positively affected the immune response of laying hens and improved the fatty acid composition of eggs.

Early Phenotype Programming in Birds by Temperature and Nutrition: A Mini-Review

Early development is a critical period during which environmental influences can have a significant impact on the health, welfare, robustness and performance of livestock. In oviparous vertebrates, such as birds, embryonic development takes place entirely in the egg. This allows the effects of environmental cues to be studied directly on the developing embryo. Interestingly, beneficial effects have been identified in several studies, leading to innovative procedures to improve the phenotype of the animals in the long term. In this review, we discuss the effects of early temperature and dietary programming strategies that both show promising results, as well as their potential transgenerational effects. The timing, duration and intensity of these procedures are critical to ensure that they produce beneficial effects without affecting animal survival or final product quality. For example, cyclic increases in egg incubation temperature have been shown to improve temperature tolerance and promote muscular growth in chickens or fatty liver production in mule ducks. In ovo feeding has also been successfully used to enhance digestive tract maturation, optimize chick development and growth, and thus obtain higher quality chicks. In addition, changes in the nutritional availability of methyl donors, for example, was shown to influence offspring phenotype. The molecular mechanisms behind early phenotype programming are still under investigation and are probably epigenetic in nature as shown by recent work in chickens.

In ovo Feeding as a Tool for Improving Performance and Gut Health of Poultry: A Review

Early growth and development of the gastrointestinal tract are of critical importance to enhance nutrients' utilization and optimize the growth of poultry. In the current production system, chicks do not have access to feed for about 48-72 h during transportation between hatchery and production farms. This lag time affects early nutrient intake, natural exposure to the microbiome, and the initiation of beneficial stimulation of the immune system of chicks. In ovo feeding can provide early nutrients and additives to embryos, stimulate gut microflora, and mitigate the adverse effects of starvation during pre-and post-hatch periods. Depending on the interests, the compounds are delivered to the embryo either around day 12 or 17 to 18 of incubation and via air sac or amnion. In ovo applications of bioactive compounds like vaccines, nutrients, antibiotics, prebiotics, probiotics, synbiotics, creatine, follistatin, L-carnitine, CpG oligodeoxynucleotide, growth hormone, polyclonal antimyostatin antibody, peptide YY, and insulin-like growth factor-1 have been studied. These compounds affect hatchability, body weight at hatch, physiological functions, immune responses, gut morphology, gut microbiome, production performance, and overall health of birds. However, the route, dose, method, and time of in ovo injection and host factors can cause variation, and thereby inconsistencies in results. Studies using this method have manifested the benefits of injection of different single bioactive compounds. But for excelling in poultry production, researchers should precisely know the proper route and time of injection, optimum dose, and effective combination of different compounds. This review paper will provide an insight into current practices and available findings related to in ovo feeding on performance and health parameters of poultry, along with challenges and future perspectives of this technique.

Development and Functional Properties of Intestinal Mucus Layer in Poultry

Intestinal mucus plays important roles in protecting the epithelial surfaces against pathogens, supporting the colonization with commensal bacteria, maintaining an appropriate environment for digestion, as well as facilitating nutrient transport from the lumen to the underlying epithelium. The mucus layer in the poultry gut is produced and preserved by mucin-secreting goblet cells that rapidly develop and mature after hatch as a response to external stimuli including environmental factors, intestinal microbiota as well as dietary factors. The ontogenetic development of goblet cells affects the mucin composition and secretion, causing an alteration in the physicochemical properties of the mucus layer. The intestinal mucus prevents the invasion of pathogens to the epithelium by its antibacterial properties (e.g. β-defensin, lysozyme, avidin and IgA) and creates a physical barrier with the ability to protect the epithelium from pathogens. Mucosal barrier is the first line of innate defense in the gastrointestinal tract. This barrier has a selective permeability that allows small particles and nutrients passing through. The structural components and functional properties of mucins have been reviewed extensively in humans and rodents, but it seems to be neglected in poultry. This review discusses the impact of age on development of goblet cells and their mucus production with relevance for the functional characteristics of mucus layer and its protective mechanism in the chicken’s intestine. Dietary factors directly and indirectly (through modification of the gut bacteria and their metabolic activities) affect goblet cell proliferation and differentiation and can be used to manipulate mucosal integrity and dynamic. However, the mode of action and mechanisms behind these effects need to be studied further. As mucins resist to digestion processes, the sloughed mucins can be utilized by bacteria in the lower part of the gut and are considered as endogenous loss of protein and energy to animal. Hydrothermal processing of poultry feed may reduce this loss by reduction in mucus shedding into the lumen. Given the significance of this loss and the lack of precise data, this matter needs to be carefully investigated in the future and the nutritional strategies reducing this loss have to be defined better.

Nutrition and Digestive Physiology of the Broiler Chick: State of the Art and Outlook

Simple Summary

The first week after hatch is the most challenging period in the life of broilers. The digestive tract of the newly hatched chick is immature and must undergo dramatic changes before it can efficiently digest and absorb nutrients. The gut is the vital organ where nutrient digestion and absorption take place. Ontogenic changes that accompany improved digestion and absorption include increased secretion of digestive enzymes, increase in the gut absorptive surface area, and enhanced nutrient transporters. The obvious limiting factors are the secretion and activities of digestive enzymes, and the surface area for absorption. These limitations are overcome as the birds grow older, with concurrent improvements in nutrient utilization. In addition, substantial changes also take place in the physical and functional development of the immune system and intestinal microbial ecology. However, the focus of the current review was on nutrition-related challenges and nutritional approaches to assist the chick during this highly demanding period.

Abstract

Because the intestine is the primary nutrient supply organ, early development of digestive function in newly hatched chick will enable it to better utilize nutrients, grow efficiently, and achieve the genetic potential of contemporary broilers. Published data on the growth and digestive function of the gastrointestinal tract in neonatal poultry were reviewed. Several potential strategies to improve digestive tract growth and function in newly hatched chick are available and the options include breeder nutrition, in ovo feeding, early access to feed and water, special pre-starter diets, judicious use of feed additives, and early programming.

Modifications in the Intestinal Functionality, Morphology and Microbiome Following Intra-Amniotic Administration (Gallus gallus) of Grape (Vitis vinifera) Stilbenes (Resveratrol and Pterostilbene)

This efficacy trial evaluated the effects of two polyphenolic stilbenes, resveratrol and pterostilbene, mostly found in grapes, on the brush border membrane functionality, morphology and gut microbiome. This study applied the validated Gallus gallus intra-amniotic approach to investigate the effects of stilbene administration versus the controls. Three treatment groups (5% resveratrol; 5% pterostilbene; and synergistic: 4.75% resveratrol and 0.25% pterostilbene) and three controls (18 MΩ H₂O; no injection; 5% inulin) were employed. We observed beneficial morphological changes, specifically an increase in the villus length, diameter, depth of crypts and goblet cell diameter in the pterostilbene and synergistic groups, with concomitant increases in the serum iron and zinc concentrations. Further, the alterations in gene expression of the mineral metabolism proteins and pro-inflammatory cytokines indicate a potential improvement in gut health and mineral bioavailability. The cecal microbiota was analyzed using 16S rRNA sequencing. A lower α-diversity was observed in the synergistic group compared with the other treatment groups. However, beneficial compositional and functional alterations in the gut microbiome were detected. Several key microbial metabolic pathways were differentially enriched in the pterostilbene treatment group. These observations demonstrate a significant bacterial–host interaction that contributed to enhancements in intestinal functionality, morphology and physiological status. Our data demonstrate a novel understanding of the nutritional benefits of dietary stilbenes and their effects on intestinal functionality, morphology and gut microbiota in vivo.

Effect of yeast cell wall supplementation on intestinal integrity, digestive enzyme activity and immune traits of broilers

1. The protective layer formed by intestinal epithelial cells acts as a barrier preventing the adhesion of pathogenic bacteria, aids digestion and passage of nutrients and reduces damage caused from toxins on the gastrointestinal tract. This study was conducted to investigate the effects of a yeast cell wall-based product (YCW), on broiler intestinal integrity, digestive enzyme capacity and immune function.2. A 35-d trial involving 246, one-d-of-hatch male broiler chickens was carried out at a trial facility at Agri-Food Biosciences Institute (AFBI, Belfast, UK). Birds were randomly allocated into 6 pens at day of hatch (41 birds/pen; 123 birds/group). Pens were divided into two groups: (1) basal diet and (2) basal diet that incorporated YCW at the manufacturers' recommended inclusion levels (Alltech Inc., Lexington, Kentucky, USA).3. In this study, YCW supplementation affected broiler intestinal morphology resulting in greater crypt depth, villus height and surface area, goblet cell density and mucus layer thickness and lower muscularis mucosae thickness. The digestive enzymes, maltase, sucrase and alkaline phosphatase, were significantly higher in the YCW supplemented group compared to the control. The expression levels of pro-inflammatory cytokines, IL-1β, IL-12 and IL-18, were significantly lower as was necroptotic cell death in YCW supplemented birds.4. In conclusion, under the conditions of this study, YCW supplementation positively affected intestinal health parameters in broilers following 35-d supplementation.

Basal ileal endogenous amino acid flow in broiler chickens as influenced by age

The current study was carried out to measure the basal ileal endogenous amino acid (EAA) flow in male broilers (Ross 308) at different ages (d 7, 14, 21, 28, 35, and 42), following the feeding of a nitrogen-free diet. Titanium dioxide (5 g/kg) was included as an indigestible marker. The nitrogen-free diet was offered for four days prior to ileal digesta collection to 6 replicate cages housing 14 (d 3–7), 12 (d 10–14), 10 (d 17–21), 8 (d 24–28), 8 (d 31–35), and 6 (d 38–42) birds per cage. The basal EAA flow was calculated as g/kg DM intake. The amino acid (AA) profile of endogenous protein, expressed as g/100 g protein, was also calculated. The basal endogenous flow of nitrogen and all individual and total AA decreased quadratically (P < 0.05 to 0.001), with flows being higher on d 7, then decreasing on d 14, plateauing until d 35 and decreasing further on d 42. The concentrations of Trp, Cys, and Gly in the endogenous protein increased linearly (P < 0.01 to 0.001) with advancing age, whereas a linear decrease (P < 0.001) was noted for Lys. A quadratic influence (P < 0.05 to 0.001) was observed for the concentrations of Ile, Leu, Met, Val, and Asp. These changes in the endogenous protein profile may be attributed to variations in the contribution of endogenous sources with age but delineating the exact contribution of different sources is complicated. Overall, the current findings suggest that the basal ileal EAA flow is influenced by broiler age and age-specific EAA flows may need to be considered to standardize the AA digestibility.

The effect of different types of in ovo selenium injection on the immunity, villi surface area, and growth performance of local chickens

Background and Aim

The presence of free radicals may lower chicken's performance. Thus, the antioxidant defense is needed and can be made through a nutritional approach such as selenium supplementation before hatches. This study aimed to investigate the type of selenium that, as an in ovo feeding (IOF) material, can provide the most enhancement of immunity, villi surface area, and early growth performance of local chickens.

Materials and Methods

This study, with a completely randomized design, used 480 fertile Kampung Unggul Balitbangtan (KUB, a selected local breed) chicken eggs, with 120 eggs per treatment for four treatments. The four treatments of IOF material included the treatment with organic selenium yeast (SY), organic hydroxy-selenomethionine (HSM), inorganic sodium selenite (SS), and uninjected selenium (control). A solution containing 0.15 ppm of different selenium was injected into the egg amnion after 18 days of incubation. Once hatched, the chicks were placed in three individual cages for each treatment (capacity of eight birds per cage). The parameters observed were the villi surface area, antibody titer, the number of total and differentiated leucocytes, glutathione peroxidase (GSH-Px) activity levels, and growth and feed efficiency of the early growth performance.

Results

All the in ovo selenium feeding, except SS, significantly affected the villi surface area, antibody titer, and lymphocyte and heterophil percentages; however, the feedings were still not optimal for enhancing antibody titers and total and differentiated leukocytes. All types of selenium were demonstrated to increase the activity of GSH-Px significantly compared to the control treatment (p<0.05). Furthermore, the daily gain and feed conversion ratio of the groups treated with SY and HSM was significantly improved compared to that of the control group.

Conclusion

In ovo SY and HSM improve immunity significantly, villi surface areas and performance. Therefore, both types are the best nutrient ingredients of IOF for building immunity and producing good performance in chickens.

The effect of delayed feeding post-hatch on caeca development in broiler chickens

1. Broiler chicks are frequently deprived of food up to 72 h due to uneven hatching rates, management procedures and transportation to farms. Little is known about the effect of delayed feeding due to extended hatching times on the early neonatal development of the caeca. Therefore, the objective of this study was to investigate the developmental changes and effects of a 48-h delay in feed access immediately post-hatch (PH) on the caeca.2. After hatch, birds (Ross 708) were randomly divided into two treatment groups (n = 6 battery pen/treatment). One group (early fed; EF) received feed and water immediately after hatch, while the second group (late fed; LF) had access to water but had delayed access to feed for 48 h. Contents averaging across all regions of the caeca were collected for mRNA expression as well as for histological analysis at -48, 0, 4 h PH and then at 1, 2, 3, 4, 6, 8, 10, 12 and 14 days PH.3. Expression of MCT-1 (a nutrient transporter), Cox7A2 (related to mitochondrial function) IgA, pIgR, and ChIL-8 (immune function) genes was affected by delayed access to feed that was dependent by the time PH. Expression of immune and gut barrier function-related genes (LEAP2 and MUC2, respectively) was increased in LF group. There was no effect of feed delay on expression of genes related to mitochondrial functions in the caeca, although developmental changes were observed (ATP5F1B, Cox4|1). Caecal mucus and muscle thickness were affected by delayed access to feed during caeca development.4. The data suggested a limited effect of delayed feed access PH on the developmental changes in caecal functions. However, the caeca seemed to be relatively resistant to delayed access to feed early PH, with only a few genes affected.

Age-related histochemical investigations of small intestinal goblet cells in bronze turkeys (Meleagris gallopavo gallopavo)

The aim of the study was to investigate the goblet cell types and their density in the small intestine of bronze turkey (Meleagris meleagris gallopovo), by means of Alcian blue-PAS staining. Sixty birds from 10 age groups were used. In the duodenum and jejunum, goblet cells produced acid, neutral and mixed mucins, while in the jejunum - acid mucins. A negative relationship was observed between cell density and either duodenum or jejunum lengths; such a correlation was not established in the ileum.

Plant origin prebiotics affect duodenal brush border membrane functionality and morphology, in vivo (Gallus Gallus)

The intra-amniotic administration approach has been used to evaluate the effects of plant origin prebiotics on intestinal health and on brush border membrane functionality and morphology. Prebiotics are fermentable dietary fibers, which can positively affect the host by selectively stimulating the growth and activity of colon bacteria, thus improving intestinal health. The consumption of prebiotics increases digestive tract motility, which leads to hyperplasia and/or hypertrophy of intestinal cells, increasing nutrient digestive and absorptive surface area. This review collates information about the effects and relationship between prebiotic consumption on small intestinal brush border membrane functionality and morphology by utilizing the intra-amniotic administration approach. To date, research has shown that the intra-amniotic administration of prebiotics affects the expression of key brush border membrane functional proteins, intestinal surface area (villi height/width), and goblet cell number/size. These effects may improve brush border membrane functionality and digestive/absorptive capabilities.

Influence of Lacto-Immuno-Vital on growth performance and gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum of broiler chickens

The effects of Lacto-Immuno-Vital synbiotic preparation on gene expression of IgA, MUC-2, and growth factor IGF-2 in the jejunum and on BW gain in broiler chickens were studied. A flock of 64,400 1-day-old Hybrid ROSS 308 chickens was inducted in the 42-day experiment. The chickens were divided into 2 equally size groups in separate halls. The chickens in the experimental (E) group received 500 g of Lacto-Immuno-Vital in 1,000 L of drinking water. The preparation was administered daily from the first day (day 1) to day 7 of the experiment. From day 7 to day 22, it was given in pulsed manner (every third day) at a dose of 300 g in 1,000 L of drinking water. The broiler chickens in the E group gained more weight (P < 0.001) compared with control from day 10 to day 42. Death of animals during feeding period was 1,078 chickens in the E group compared with 1,115 dead chickens in the control group. Feed conversion ratio was 1.61 kg of supplemented diet/kg of BW in the E group compare with 1.67 kg of nonsupplemented diet/kg of BW in control. The relative expression of IgA gene in the jejunum was upregulated on day 22 in the E group compared with control (P < 0.05), whereas relative expression of MUC-2 gene was upregulated in the E group compared with control on day 8 and day 22 (P < 0.05; P < 0.001). Similarly, relative expression of IGF-2 gene was upregulated in the E group compared with control on both samplings (P < 0.01). The composition of Lacto-Immuno-Vital synbiotic preparation showed beneficial effects on growth performance, feed conversion ratio, morbidity, mortality, and selected parameters of mucosal immunity in the chicken jejunum.

Chicken embryo development: metabolic and morphological basis for in ovo feeding technology

Broiler embryonic development depends on the nutrients that are available in the egg, which includes mostly water, lipids, and proteins. Carbohydrates represent less than 1%, and free glucose only 0.3%, of the total nutrients. Considering that energy requirements increase during incubation and metabolism is shifted toward the use of glycogen stores and gluconeogenesis from amino acids, extensive muscle protein degradation in the end of incubation can compromise chick development in the initial days after hatch. Significant prehatch changes occur in embryonic metabolism to parallel the rapid embryonic development. Oral consumption of the amniotic fluid begins around 17 d of incubation and promotes rapid development of the intestinal mucosa, which is characterized by morphological changes and increased expression and activity of enzymes and transporters. Furthermore, ingested substrates are stored as nutritional reserves to be used during hatching and in the first week after hatch. At hatch, this limited-nutrient store is directed to the functional development of the gastrointestinal tract to enable assimilation of exogenous nutrients. In ovo feeding is an alternative to deliver essential nutrients to chick embryos at this critical and challenging phase. The improved nutritional status and physiological changes triggered by in ovo feeding can resonate throughout the entire rearing period with significant health and economic gains. The present review addresses the main changes in metabolism and intestinal development throughout incubation, and also addresses scientific advances, limitations and future perspectives associated with the use of in ovo feeding that has been regarded as an important technology by the poultry industry.

Alterations in the Intestinal Morphology, Gut Microbiota, and Trace Mineral Status Following Intra-Amniotic Administration (Gallus gallus) of Teff (Eragrostis tef) Seed Extracts

The consumption of teff (Eragrostis tef), a gluten-free cereal grain, has increased due to its dense nutrient composition including complex carbohydrates, unsaturated fatty acids, trace minerals (especially Fe), and phytochemicals. This study utilized the clinically-validated Gallus gallus intra amniotic feeding model to assess the effects of intra-amniotic administration of teff extracts versus controls using seven groups: (1) non-injected; (2) 18Ω H₂O injected; (3) 5% inulin; (4) teff extract 1%; (5) teff extract 2.5%; (6) teff extract 5%; and (7) teff extract 7.5%. The treatment groups were compared to each other and to controls. Our data demonstrated a significant improvement in hepatic iron (Fe) and zinc (Zn) concentration and LA:DGLA ratio without concomitant serum concentration changes, up-regulation of various Fe and Zn brush border membrane proteins, and beneficial morphological changes to duodenal villi and goblet cells. No significant taxonomic alterations were observed using 16S rRNA sequencing of the cecal microbiota. Several important bacterial metabolic pathways were differentially enriched in the teff group, likely due to teff’s high relative fiber concentration, demonstrating an important bacterial-host interaction that contributed to improvements in the physiological status of Fe and Zn. Therefore, teff appeared to represent a promising staple food crop and should be further evaluated.

Effect of delayed feeding post-hatch on expression of tight junction- and gut barrier-related genes in the small intestine of broiler chickens during neonatal development

The gut not only plays a key role in digestion and absorption of nutrients but also forms a physical barrier and first line of defense between the host and the luminal environment. A functional gut barrier (mucus and epithelial cells with tight junctions [TJ]) is essential for optimal health and efficient production in poultry. In current broiler system, chicks are deprived of food and water up to 72 h due to uneven hatching, hatchery procedures, and transportation. Post-hatch feed delay results in lower BW, higher FCR and mortality, and delayed post-hatch gut development. Little is known about the effects of early neonatal development and delayed feeding immediately post-hatch on gut barrier function in chickens. Therefore, the aim of the present study was to characterize the expression pattern of gut barrier-related and TJ-related genes in the small intestine of broiler chickens during early development and delay in access to feed. Newly hatched chicks received feed and water immediately after hatch or were subjected to 48 h delayed access to feed to mimic commercial hatchery setting and operations. Birds were sampled (n = 6) at -48, 0, 4, 24, 48, 72, 96, 144, 192, 240, 288, and 336 h post-hatch. Jejunum and ileum were collected, cleaned of digesta, and snap-frozen in liquid nitrogen or fixed in paraformaldehyde. The relative mRNA levels of gut barrier- and TJ-related protein genes were measured by quantitative PCR and analyzed by 2-way ANOVA. In both tissues, changes (P < 0.05) in gene expression pattern of gut barrier-related and TJ-related genes were detected due to delayed access to feed post-hatch and/or development. In general, expression of TJ-related genes was downregulated while mRNA levels of gut barrier-related genes were upregulated during development. Histological differences and changes in mucin staining due to age and treatment were observed. These results suggest that delayed access to feed post-hatch may affect TJ structure and/or function and therefore gut barrier function and overall health of the chicken small intestine.

Effects of putrescine injection in broiler breeder eggs

The aim of this study was to evaluate the effects of increasing doses of putrescine injected in ovo on hatchability, intestinal morphology and pre-starter performance of broilers. For this purpose, 720 eggs from broiler breeders were separated into a negative control (no injection) and injection treatments with increasing doses of putrescine (0.05; 0.1; 0.15 and 0.2%), totalling five treatments of 144 eggs each. Eggs were distributed in a completely randomized design inside the setter and the injection of solutions occurred at 17 days of incubation. After hatch, 330 birds were housed in mixed lots following the original treatments, totalling 5 treatments of 6 replicates with 11 birds each. Six birds per treatment were weighed and euthanized by cervical dislocation to collect the liver, intestine and breast 24 hr after injection, at hatch and 24 hr after hatch. At 2 days of age, intestines were collected from 4 animals per treatment to analyse histomorphology. The effects of putrescine levels were evaluated by polynomial regression models, ANOVA and Tukey test at 5% probability. The hatchability decreased linearly in response to increased doses of putrescine. The percentage of residual yolk was lower in animals that received putrescine compared to the control. After injection, the percentage of breast increased linearly, and the percentage of intestine had a quadratic response to increased doses of putrescine. However, 24 hr after hatch, the percentage of intestine linearly decreased, and the percentage of liver linearly increased in response to increased doses of putrescine. Villus height increased quadratically, crypt depth decreased linearly, and goblet cells increased linearly in response to the putrescine dose. FI and BWG were not affected in the pre-starter phase; however, FCR increased in response to increased levels of putrescine. Due to putrescine effects on embryos, it is recommended that the doses injected in ovo not exceed 0.1%.

Delayed access to feed affects broiler small intestinal morphology and goblet cell ontogeny

Broilers are often deprived of feed and water for up to 48 h after hatch. This delayed access to feed (DAF) can inhibit small intestine development. The objective of this study was to determine the effects of DAF on small intestinal morphology, mRNA abundance of the goblet cell marker Muc2 and absorptive cell marker PepT1, and the distribution of goblet cells in young broilers. Cobb 500 chicks, hatching within a 12-h window, were randomly allocated into 3 groups: control with no feed delay (ND), 24-h feed delay (DAF24), and 36-h feed delay (DAF36). Morphology, gene expression, and in situ hybridization analyses were conducted on the duodenum, jejunum, and ileum at 0, 24, 36, 72, 120, and 168 h after hatch. Statistical analysis was performed using a t test for ND and DAF24 at 24 h. A 2-way ANOVA and Tukey's HSD test (P < 0.05) were used for ND, DAF24, and DAF36 from 36 h. At 24 to 36 h, DAF decreased the ratio of villus height/crypt depth (VH/CD) in the duodenum but increased VH/CD in the ileum due to changes in CD, whereas at 72 h, DAF decreased VH/CD due to a decrease in VH. The mRNA abundance of PepT1 was upregulated, while Muc2 mRNA was downregulated in DAF chicks. Cells expressing Muc2 mRNA were present along the villi and in the crypts. The ratio of the number of goblet cells found in the upper half to the lower half of the villus was greater in DAF chicks than in ND chicks, suggesting that DAF affected the appearance of new goblet cells. The number of Muc2 mRNA-expressing cells in the crypt, however, was generally not affected by DAF. In conclusion, DAF transiently affected small intestinal morphology, upregulated PepT1 mRNA, downregulated Muc2 mRNA, and changed the distribution of goblet cells in the villi. By 168 h, however, these parameters were not different between ND, DAF24, and DAF36 chicks.

Effects of in ovo feeding of N-acetyl-L-glutamate on early intestinal development and growth performance in broiler chickens

The present study determined the effects of in ovo feeding (IOF) of N-acetyl-L-glutamate (NAG) on early intestinal development and growth performance of broilers. A total of 702 fertile broiler eggs were randomly divided into 3 treatments: 1) non-punctured control group, 2) saline-injected control group, and 3) NAG solution-injected group (1.5 mg/egg). At 17.5 D of incubation, 300 μL of each solution was injected into each egg of injected groups. Results indicated that the hatchability and healthy chicken rate were not affected by NAG injection (P > 0.05). Chicks from NAG solution-injected group had significantly decreased average daily feed intake and feed conversion ratio during 1-14 D than those in the non-punctured control group (P < 0.05). Compared with the non-punctured control group, IOF of NAG significantly increased the density of goblet cells in jejunum at hatch, duodenum at 7 D, and ileum at 14 D; decreased crypt depth in jejunum at hatch; and increased villus height in duodenum and jejunum and villus height:crypt depth ratio in duodenum at 7 D (P < 0.05). The intestinal mRNA expression of Na⁺-dependent neutral amino acid transporter, peptide transporter, and excitatory amino acid transporter 3 did not differ between groups at 7 or 14 D. However, the mRNA expression level of rBAT in jejunum significantly increased in the NAG solution-injected group than in the non-punctured control group at 7 D (P < 0.05). In conclusion, IOF of NAG (1.5 mg/egg) accelerated the early intestinal development by enhancing intestinal immune and absorption function, thereby positively affecting the feed efficiency for the first 2 wk post-hatch.