Dietary supplementation with free methionine or methionine dipeptide mitigates intestinal oxidative stress induced by Eimeria spp. challenge in broiler chickens

Major Oxidative and Antioxidant Mechanisms During Heat Stress-Induced Oxidative Stress in Chickens

Heat stress (HS) is one of the most important stressors in chickens, and its adverse effects are primarily caused by disturbing the redox homeostasis. An increase in electron leakage from the mitochondrial electron transport chain is the major source of free radical production under HS, which triggers other enzymatic systems to generate more radicals. As a defense mechanism, cells have enzymatic and non-enzymatic antioxidant systems that work cooperatively against free radicals. The generation of free radicals, particularly the reactive oxygen species (ROS) and reactive nitrogen species (RNS), under HS condition outweighs the cellular antioxidant capacity, resulting in oxidative damage to macromolecules, including lipids, carbohydrates, proteins, and DNA. Understanding these detrimental oxidative processes and protective defense mechanisms is important in developing mitigation strategies against HS. This review summarizes the current understanding of major oxidative and antioxidant systems and their molecular mechanisms in generating or neutralizing the ROS/RNS. Importantly, this review explores the potential mechanisms that lead to the development of oxidative stress in heat-stressed chickens, highlighting their unique behavioral and physiological responses against thermal stress. Further, we summarize the major findings associated with these oxidative and antioxidant mechanisms in chickens.

Characterization of fillets and skins from two varieties of genetically improved farmed Nile tilapia (Oreochromis niloticus)

Genetically improved farmed tilapia (GIFT) is a strain of Nile tilapia (Oreochromis niloticus) developed for improved production and commercial parameters. Skin color, one of the characteristics distinguishing tilapia varieties, is an important phenotypic trait associated with qualitative and productive performance. This study aimed to assess fillet and skin characteristics in GIFT Nile tilapia with black and red skin phenotypes. For this, 24 GIFT Nile tilapia from the same spawning stock were divided into two groups based on skin color, namely a black variety (dark skin) and a red variety (reddish skin). There were no significant differences in biometric parameters between varieties. Fish of the red variety had higher 2 h post-slaughter pH and muscle antioxidant capacity and lower yellow-blue axis value (b*), luminosity (L*), thawing loss, cooking loss, and conjugated diene content (P < 0.05). The skin of black tilapia exhibited higher force in the progressive tear test tear, and higher strength, tensile strength, deformation, and elongation in the traction and stretching test than that of red tilapia. Black tilapia skin had higher collagen and hydroxyproline contents. The skin of the red variety exhibited higher expression levels of alpha 1, 2, and 3 type I collagen genes, lower expression levels of the vimentin gene, and higher antioxidant capacity. The results suggest that skin color phenotype may be linked to important metabolic pathways influencing fish fillet and skin traits. These findings can support future research aimed at identifying optimal varieties of Nile tilapia for specific purposes and optimizing the utilization of filleting waste.

Effects of Amino Acid Supplementation on the Growth Performance of Broiler Chicks Challenged With Coccidiosis: A Meta-Analysis

This meta-analysis aimed to evaluate the effects of amino acid supplementation on the growth performance of broiler chicks challenged with coccidiosis. Data were collected on authorship, publication year, study sample characteristics and outcomes of interest related to growth performance. Effect sizes were calculated for both overall effects and the individual effects of each amino acid. The effects of moderator factors, such as supplementation levels and duration, were also assessed, and bias was calculated. Works were obtained from PubMed, Elsevier, ScienceDirect, Wiley, Springer Link and Scopus databases, with the help of search engines like Google Scholar and ResearchGate, covering the period from 2013 to 2023. A random-effects model was used. Thirteen works were included in the current analysis, examining the effects of arginine (n = 4), methionine (n = 6), threonine (n = 3) and glutamine (n = 3). Amino acid supplementation [0.326, CI 95% (0.297-0.355); p = 0.000], arginine [0.430, CI 95% (0.293-0.568); p = 0.000] and threonine [0.793, CI 95% (0.193-1.38); p = 0.009] significantly increased body weight. Amino acid supplementation [0.052, CI 95% (0.022-0.081); p = 0.000] and arginine [0.317, CI 95% (0.049-0.585); p = 0.000] also significantly increased feed intake. Higher levels of amino acids (≥1.50%) and longer supplementation periods (≥15 days) significantly increased body weight and feed intake, while reducing the feed conversion ratio. Funnel plots, fail-safe N and Egger tests showed no evidence of bias. In conclusion, arginine supplementation has the potential to increase body weight and feed intake in poultry challenged with coccidiosis. Higher doses of amino acids and longer supplementation periods are recommended in such cases.

Effect of orally administered B. subtilis-cNK-2 on growth performance, immunity, gut health, and gut microbiome in chickens infected with Eimeria acervulina and its potential as an alternative to antibiotics

This study investigated the best oral delivery strategy (gavage or feed) for the B. subtilis expressing the chicken anti-microbial peptide cNK-2 (B. subtilis-cNK-2) in comparison to monensin, in chickens challenged with Eimeria acervulina (E. acervulina). A total of 120 broiler chickens were randomly allocated into 5 treatment groups in a completely randomized design: 1) uninfected chickens fed with basal diet (NC), 2) E. acervulina-infected chickens fed a basal diet (PC), 3) E. acervulina-infected chickens fed a basal diet supplemented with 90 mg monensin/kg feed (MO), 4) E. acervulina-infected chickens fed a basal diet and orally gavaged with B. subtilis-cNK-2 at 1 × 1010 cfu/d (CNK-O), and 5) E. acervulina-infected chickens fed a basal diet mixed with B. subtilis-cNK-2 at 1 × 1010 cfu/kg feed (CNK-F). The challenge consisted of 5,000 sporulated E. acervulina oocysts through oral gavage on d 15. Body weights were measured on d 7, 14, 21, and 23. Duodenal tissue and digesta samples were collected at 6 d postinfection (dpi) to assess the gut integrity, oxidative stress, mucosal immunity, and the gut microbiome. Fecal samples were collected from 6 to 8 dpi to enumerate the oocyst shedding. Chickens in the CNK-O group showed improved (P < 0.05) growth performance, gut integrity, and mucosal immunity compared to PC, comparable to chickens in the MO group. Chickens in the MO, CNK-F, and CNK-O treatment groups all showed lower (P < 0.05) oocyst shedding compared to PC chickens. Moreover, distinct cytokine profile, oxidative stress measures, tight junction proteins, and shifts in the gut microbiome with associated functional changes were observed in all challenge groups. In conclusion, we showed that the oral administration of B. subtilis-cNK-2 improved growth performance, enhanced local protective immunity, and reduced fecal oocyst shedding in broiler chickens infected with E. acervulina, demonstrating potential use of B. subtilis-cNK-2 as an alternative to antibiotics to protect chickens against coccidiosis.

Effects of inclusion of the blend of essential oils, organic acids, curcumin, tannins, vitamin E, and zinc in the maternal diet, and of incubation temperature on early and late development of quail

The maternal diet and egg incubation temperature are some of the factors that can influence the embryonic development and performance of the newly chicks at 15 d of age. This study evaluated the effects of adding a blend of organic acids, essential oils, curcumin, tannins, vitamin E, and zinc microencapsulated in to the diet of female quails (Coturnix coturnix japonica) on their productive, reproductive performance and redox parameters of their eggs and the interaction of maternal diet × incubation temperature on embryo (E16 and E18) and chicks development. At 98 d of age, 64 female quails with a mean body weight of 150 g ± 0.5 were distributed into two treatments: a Basal diet or a diet supplemented with blend (Sannimix). The eggs from each female were incubated at 37.5°C (Control) and 38.5°C (High Temperature) throughout the incubation period. After hatching, chicks were distributed in a 2 (maternal diet) × 2 (incubation temperature) factorial design. Female quails supplemented with Sannimix showed better productive and reproductive performance and produced higher-quality embryos. Their offspring had greater weight at hatch and at 15 d of age. The eggs and offspring of supplemented with Sannimix female quails showed better oxidative stability. At E16 and E18, High Temperature increased yolk sac utilization and gene expression of the growth hormone receptor (GHR). At E16, embryos from supplemented with Sannimix female quail had higher expression of insulin-like growth factor type I (IGFI) and heat shock protein 70 kDa genes. At 15 d of age, highest expression of the GHR and IGFI genes was observed in chicks from female quails fed the Sannimix diet, regardless of incubation temperature. Regarding the maternal diet × incubation temperature an improved result was observed for chicks from female quails fed with Sannimix even when eggs are exposed to High Temperature during the incubation. The supplementation of quail diets with blend Sannimix improves productive and reproductive performance, egg quality and their embryos, as well as their offspring quality.

Acute phase response and oxidative stress in coccidiosis: A review in domestic animals

Coccidiosis is a highly significant disease in domestic animals due to its global distribution and economic impact. The occurrence of oxidative stress (OS) and the acute phase response (APR) play crucial roles in the development of coccidiosis, thereby contributing to the pathogenicity of coccidia. A range of triggers including parasitic infection, can induce the APR. This response encompasses a set of hormonal and metabolic changes to restore body stability and improve the body's healing capabilities. Ovine coccidiosis has the potential to cause OS, which can be prevented and treated through the use of dietary additives. By including Curcuma longa in the diets of infected sheep, it is possible to reduce lipid peroxidation (LPO) and nitric oxide (NO) production, while simultaneously improving serum antioxidant capacity and interleukin-10 (IL-10) levels. Caprine coccidiosis can activate the APR. Research indicated that goats suffering from coccidiosis exhibited elevated concentrations of malondialdehyde (MDA) and total homocysteine, along with reduced levels of some enzymes such as superoxide dismutase (SOD) and glutathione reductase (GR), as well as decreased levels of zinc (Zn), manganese (Mn), selenium (Se), vitamin C, and total antioxidant capacity (TAC). Bovine coccidiosis is linked to elevated MDA concentrations and reduced serum glutathione (GSH) and TAC levels. Eimeria can induce OS and inflammatory damage in infected birds by releasing pro-inflammatory mediators from cells, resulting in a significant increase in CAT and SOD activity, lipid peroxidation and damage to the intestinal epithelium. To promote the antioxidant system of infected birds, some herbal food additives such as grape seed proanthocyanidine extract, Curcuma longa and Rumex nervosus leaf extract, can be used. Research on the APR in birds is not as extensive as in ruminants. Currently, there is a lack of studies on the occurrence of OS and APR in camels, horses, dogs, and cats with coccidiosis.

The effect of gut microbiota-derived carnosine on mucosal integrity and immunity in broiler chickens challenged with Eimeria maxima

In the first study, an in vitro culture system was developed to investigate the effects of carnosine on macrophage proinflammatory cytokine response using an established chicken macrophage cell line (CMC), gut integrity using a chicken intestinal epithelial cell line (IEC), muscle differentiation in quail muscle cells (QMCs) and primary chicken embryonic muscle cells (PMCs), and direct anti-parasitic effect against Eimeria maxima sporozoites. Cells to be tested were seeded in 24-well plates and treated with carnosine at 4 different concentrations (0.1, 1.0, and 10.0 µg). After 18 h of incubation, cells were harvested to measure gene expression of proinflammatory cytokines in CMC, tight junction (TJ) proteins in IECs, and muscle cell growth markers in QMCs and PMCs. In vivo trials were conducted to investigate the effect of dietary carnosine on disease parameters in broiler chickens challenged with E. maxima. One hundred and twenty male broiler chickens (0-day-old) were allocated into 4 treatment groups: 1) basal diet without infection (NC), 2) basal diet with E. maxima infection (PC), 3) carnosine at 10.0 mg/kg feed with PC (HCS), and 4) carnosine at 1.0 mg/kg feed with PC (LCS). All groups except NC were orally infected with E. maxima on d 14. Jejunal samples were collected for lesion scoring and jejunum gut tissues were used for transcriptomic analysis of cytokines and TJ proteins. In vitro, carnosine treatment significantly decreased IL-1β gene expression in CMC following LPS stimulation. In vivo feeding studies showed that dietary carnosine increased BW and ADG of chickens in E. maxima-infected groups and reduced the jejunal lesion score and fecal oocyst shedding in HCS group. Jejunal IL-1β, IL-8, and IFN-γ expression were suppressed in the HCS group compared to PC. The expression levels of claudin-1 and occludin in IECs were also increased in HCS following carnosine treatment. In conclusion, these findings highlight the beneficial effects of dietary carnosine supplementation on intestinal immune responses and gut barrier function in broiler chickens exposed to E. maxima infection.

Effects of Dietary Inclusion of a Proprietary Combination of Quillaja saponaria and Yucca schidigera on Intestinal Permeability and Immune Response in Broiler Chickens during a Coccidia Challenge

This study assessed the impact of Magni-Phi Ultra (MPU) inclusion on intestinal integrity and immunity in broiler chickens challenged with coccidia during peak and recovery phases. A total of 128 male Ross 708 broiler chicks were randomly allotted to one of four treatment groups (four chicks/cage). Treatments included an uninfected control (UUC); a coccidial challenge (CC) infected control (IUC); a CC fed salinomycin at 66 ppm (SAL); and a CC fed Magni-Phi Ultra at 0.11 g/kg of diet (MPU). At 16 days post-hatch, all birds in the CC groups were orally gavaged with a 3× dose of a live coccidia vaccine. At 5 dpi, the birds fed MPU and SAL showed decreased plasma FITC-d, oocyte shedding, and lesion scores and higher BWG compared to the IUC birds (p < 0.05). Jejunum IL-17, IL-10, and IFN-ϒ mRNA expression was higher in the IUC compared to the UUC (p < 0.05) group at 5 dpi. At 12 dpi, the birds fed MPU or SAL had lower plasma FITC-d and jejunum IFN-ϒ and IL-10 mRNA expression compared to the IUC birds (p < 0.05). This study indicates that MPU supports intestinal integrity and mucosal immune responses during the peak and recovery phases of infection, which may lead to improved health and performance.

The Functional Roles of Methionine and Arginine in Intestinal and Bone Health of Poultry: Review

This review explores the roles of methionine and arginine in promoting the well-being of poultry, with a specific focus on their impacts on intestinal and bone health. The metabolic pathways of methionine and arginine are elucidated, highlighting their distinct routes within the avian system. Beyond their fundamental importance in protein synthesis, methionine and arginine also exert their functional roles through their antioxidant capacities, immunomodulating effects, and involvement in the synthesis of metabolically important molecules such as S-adenosylmethionine, nitric oxide, and polyamines. These multifaceted actions enable methionine and arginine to influence various aspects of intestinal health such as maintaining the integrity of the intestinal barrier, regulating immune responses, and even influencing the composition of the gut microbiota. Additionally, they could play a pivotal role in promoting bone development and regulating bone remodeling, ultimately fostering optimal bone health. In conclusion, this review provides a comprehensive understanding of the potential roles of methionine and arginine in intestinal and bone health in poultry, thereby contributing to advancing the nutrition, overall health, and productivity of poultry in a sustainable manner.

Quantitative microbiome profiling reveals the developmental trajectory of the chicken gut microbiota and its connection to host metabolism

Revealing the assembly and succession of the chicken gut microbiota is critical for a better understanding of its role in chicken physiology and metabolism. However, few studies have examined dynamic changes of absolute chicken gut microbes using the quantitative microbiome profiling (QMP) method. Here, we revealed the developmental trajectory of the broiler chicken gut bacteriome and mycobiome by combining high-throughput sequencing with a microbial load quantification assay. We showed that chicken gut microbiota abundance and diversity reached a plateau at 7 days posthatch (DPH), forming segment-specific community types after 1 DPH. The bacteriome was more impacted by deterministic processes, and the mycobiome was more affected by stochastic processes. We also observed stage-specific microbes in different gut segments, and three microbial occurrence patterns including "colonization," "disappearance," and "core" were defined. The microbial co-occurrence networks were very different among gut segments, with more positive associations than negative associations. Furthermore, we provided links between the absolute changes in chicken gut microbiota and their serum metabolite variations. Time-course untargeted metabolomics revealed six metabolite clusters with different changing patterns of abundance. The foregut microbiota had more connections with chicken serum metabolites, and the gut microbes were closely related to chicken lipid and amino acid metabolism. The present study provided a full landscape of chicken gut microbiota development in a quantitative manner, and the associations between gut microbes and chicken serum metabolites further highlight the impact of gut microbiota in chicken growth and development.

Botanicals: A promising approach for controlling cecal coccidiosis in poultry

Avian species have long struggled with the problem of coccidiosis, a disease that affects various parts of the intestine, including the anterior gut, midgut, and hindgut. Among different types of coccidiosis, cecal coccidiosis is particularly dangerous to avian species. Chickens and turkeys are commercial flocks; thus, their parasites have remained critical due to their economic importance. High rates of mortality and morbidity are observed in both chickens and turkeys due to cecal coccidiosis. Coccidiostats and coccidiocidal chemicals have traditionally been added to feed and water to control coccidiosis. However, after the EU banned their use because of issues of resistance and public health, alternative methods are being explored. Vaccines are also being used, but their efficacy and cost-effectiveness remain as challenges. Researchers are attempting to find alternatives, and among the alternatives, botanicals are a promising choice. Botanicals contain multiple active compounds such as phenolics, saponins, terpenes, sulfur compounds, etc., which can kill sporozoites and oocysts and stop the replication of Eimeria. These botanicals are primarily used as anticoccidials due to their antioxidant and immunomodulatory activities. Because of the medicinal properties of botanicals, some commercial products have also been developed. However, further research is needed to confirm their pharmacological effects, mechanisms of action, and methods of concentrated preparation. In this review, an attempt has been made to summarize the plants that have the potential to act as anticoccidials and to explain the mode of action of different compounds found within them.

Double-Fermented Soybean Meal Totally Replaces Soybean Meal in Broiler Rations with Favorable Impact on Performance, Digestibility, Amino Acids Transporters and Meat Nutritional Value

Inclusion of microbial fermented soybean meal in broiler feed has induced advantageous outcomes for their performance and gastrointestinal health via exhibiting probiotic effects. In this study, soybean meal (SBM) was subjected to double-stage microbial fermentation utilizing functional metabolites of fungi and bacteria. In broiler diet, DFSBM replaced SBM by 0, 25, 50 and 100%. DFSBM was reported to have higher protein content and total essential, nonessential and free amino acids (increased by 3.67%, 12.81%, 10.10% and 5.88-fold, respectively, compared to SBM). Notably, phytase activity and lactic acid bacteria increased, while fiber, lipid and trypsin inhibitor contents were decreased by 14.05%, 38.24% and 72.80%, respectively, in a diet containing 100% DFSBM, compared to SBM. Improved growth performance and apparent nutrient digestibility, including phosphorus and calcium, and pancreatic digestive enzyme activities were observed in groups fed higher DFSBM levels. In addition, higher inclusion levels of DFSBM increased blood immune response (IgG, IgM, nitric oxide and lysozyme levels) and liver antioxidant status. Jejunal amino acids- and peptide transporter-encoding genes (LAT1, CAT-1, CAT-2, PepT-1 and PepT-2) were upregulated with increasing levels of DFSBM in the ration. Breast muscle crude protein, calcium and phosphorus retention were increased, especially at higher inclusion levels of DFSBM. Coliform bacteria load was significantly reduced, while lactic acid bacteria count in broiler intestines was increased with higher dietary levels of DFSBM. In conclusion, replacement of SBM with DFSBM positively impacted broiler chicken feed utilization and boosted chickens’ amino acid transportation, in addition to improving the nutritional value of their breast meat.

The Naked Neck Gene in the Domestic Chicken: A Genetic Strategy to Mitigate the Impact of Heat Stress in Poultry Production—A Review

The poultry sector is one of the most important food industries in the world. Poultry production generates high-value protein products (meat and eggs) that are produced efficiently without the need for large areas. In poultry production, especially in the tropics, environmental factors, such as temperature and humidity, play a major role. Heat stress (HS) causes behavioral, physical, and physiological changes in poultry, with severe financial impacts. Therefore, it is important to find strategies to minimize it. The naked neck (Na) is an autosomal, incompletely dominant gene. Compared with normal feathered birds, these animals are known for their ability to adapt, perform, and reproduce under hot and humid climate conditions. Due to the absence of feathers on the neck, these animals increase heat dissipation, alleviating adverse heat effects, especially on productive performance. Genetic improvement of heat tolerance may provide a low-cost solution, of particular interest for developing countries in the tropics. The focus of this review is to evaluate the impact of HS in poultry with a special emphasis on the advantages of using the Na gene.

The effect of light regime and time of slaughter in broiler on broiler performance, liver antioxidant status, and expression of genes related to peptide absorption in the jejunum and melatonin synthesis in the brain

This study aimed to assess the effects of light regime and time of slaughter on primal cut and organ weights, peptide transporter 1 (PEPT1) gene expression in the jejunum, arylalkylamine N-acetyltransferase (AANAT) gene expression in the brain, and liver oxidant/antioxidant status in broilers aged 37 days. The experiment was conducted in a factorial completely randomized design, with two light regimes (intermittent light varying according to bird age and continuous light under an 18 h light/6 h dark photoperiod) and four times of slaughter (2:00, 8:00, 14:00 and 20:00 h). There was an interaction effect on PEPT1 and AANAT expression, lipid and protein oxidation and superoxide dismutase (SOD) activity. In both light regimes, PEPT1 expression responded cubically to slaughter time. In the continuous light group, PEPT1 expression was highest in birds slaughtered at 2:00 and 14:00 h, whereas, in the intermittent light treatment, expression was highest at 8:00 h. In the continuous light regime, AANAT expression had a cubic relationship with time of slaughter, with the greatest values recorded at 20:00 h. In the intermittent light regime, slaughter time showed a cubic effect on lipid oxidation, which was highest at 8:00 h. In the continuous light group, there was a cubic effect on nitrite concentration, lipid oxidation, protein oxidation, and SOD activity; nitrite levels, lipid oxidation, and protein oxidation were highest and SOD activity was lowest in birds slaughtered at 14:00 h. Time of slaughter influenced catalase activity, which responded cubically; catalase activity was lowest at 8:00 and 14:00 h. This study is the first to demonstrate that PEPT1 expression in the jejunum of broilers follows a diurnal rhythm and varies according to light regime. The results also suggest that mainly continuous lighting and slaughter at 14:00 h when the animals are possibly more active may be more stressful to broilers.

Effects of levels of methionine supplementations in forms of L or DL-methionine on the performance, intestinal development, immune response, and antioxidant system in broilers challenged with Eimeria spp

The study was conducted to investigate the effects of 2 isoforms of methionine on growth performance and intestinal health induced by methionine (Met) deficiency and Eimeria infection in broilers. A total of 720 one-day old male chicks (Cobb500) were randomly allocated to 10 groups in a 2 × 5 factorial arrangement (6 reps/group, 12 birds/cage) with diets and Eimeria challenge as the main factors. Hundred percent DL-Met, 100% L-Met, 80% DL-Met, and 80% L-Met diets were formulated to meet approximately 100 or 80% of the total sulfur amino acid (TSAA) requirement with DL-Met or L-Met as Met supplementation sources. The 60% TSAA basal diet (60% Met) was formulated without Met supplementation. At d14, the challenge groups were gavaged with mixed Eimeria spp. Growth performance was recorded on d7, 14, 20 (6-day postinfection [DPI]), and 26 (12 DPI). The gut permeability was measured on 5 and 11 DPI. Antioxidant status and gene expression of immune cytokines and tight junction proteins were measured on 6 and 12 DPI. Data were analyzed by 1-way and 2-way ANOVA before and after the challenge, respectively. Orthogonal polynomial contrasts were used for post hoc comparison. Overall, the Eimeria challenge and 60% Met diet significantly reduced growth performance, antioxidant status, and mRNA expression of tight junction genes and immune cytokines. For other Met treatments, the L-Met groups had significantly higher BWG and lower FCR than the DL-Met group from d 1 to 20. The L-Met groups had less gut permeability than the DL-Met groups on 5 DPI. Compared to the 80% Met groups, the 100% Met groups reduced gut permeability. At 6 DPI, the 80% Met groups showed higher ZO1 expression than the 100% Met groups. The challenge groups had higher Muc2 expression and GSH/GSSG compared to the nonchallenge groups, and SOD activity was lower in the L-Met groups compared to the DL-Met groups at 6 DPI. The 100% Met groups had higher GPx activity than the 80% Met groups at 12 DPI. In conclusion, during coccidiosis, the 100% Met groups had better gut integrity and antioxidant status. Met supplementation in the form of L-Met improved growth performance in the starter phase and gut permeability in the challenge phase.

Linoleic acid ameliorates intestinal mucosal barrier injury in early weaned pigeon squabs (Columba livia)

The study aimed to investigate whether linoleic acid could improve the intestinal barrier function of squabs under weaning stress conditions. Totally 320 7-d-old weaned squabs were randomly divided into four treatment groups, including control group (CON), 0.7% linoleic acid addition group (LA007), 1.4% linoleic acid addition group (LA014) and 2.1% linoleic acid addition group (LA021). At 21 d, eight squabs were randomly selected from each treatment group for sampling and determination. The results showed that adding linoleic acid could improve (P < 0.05) the body weight of weaned squabs, and LA014 had the best effect. With the increase of linoleic acid dosage, villi height and villi area increased linearly or quadratically (P < 0.05), and reached the maximum in LA021 or LA014, respectively. The linoleic acid supplementation could improve the intestinal tight junction of weaned squabs, and the LA014 was the most significant (P < 0.05). With the linoleic acid increasing, the levels of intestinal IL-6 and TNF-α decreased linearly (P < 0.05), while intestinal IL-10 increased quadratically (P < 0.05) and reached the maximum in LA014. Serum endotoxin and diamine oxidase levels decreased linearly (P < 0.05) and reached the lowest level in LA014. The ultrastructure of villi revealed that the length of ileal microvilli in LA014 was significantly increased (P < 0.05) and the microvilli became dense, and the mitochondria in epithelial cells returned to normal state. Further exploring the mechanism of linoleic acid alleviating intestinal injury caused by weaning stress in squabs, it was found that linoleic acid down-regulated (P < 0.05) the relative protein expression of TLR4, MyD88, phosphorylated JNK, and phosphorylated p38, reducing secretion of pro-inflammatory factors IL-6 and TNF-α. This study indicated that linoleic acid could alleviate intestinal barrier injury of early weaned squabs by down-regulating TLR4-MyD88-JNK/p38-IL6/TNF-α pathway.

Effect of substitution of taurine for methionine and additional taurine supplementation on the performance and antioxidative capacity of laying hens

Taurine (TAU), a sulfur-containing amino acid that synthesized from methionine and cystine, plays vital roles in maintenance of redox balance. The effect of substitution of TAU for methionine was evaluated in vivo and in vitro. The effects of replacing methionine with TAU and additional TAU supplementation on the performance and antioxidant capacity of laying hens were evaluated. The in vitro cultured chicken primary hepatocytes and intestinal epithelial cells were further employed. Two hubdred eighty-eight 40-wk-old Isa brown laying hens were divided into 4 groups and subjected one to the following treatments: fed with basal diet with 0.17% crystallized DL-Met (CON), the control diet and replace 25% (21% total Met, 21TAU) or 50% (42% total Met, 42TAU) of crystallized DL-Met with taurine, the control diet supplemented with 0.1% taurine (0.1% TAU). The laying rate, feed intake, egg weight, and feed efficiency were not influenced (P > 0.05) by TAU replacement or additional TAU supplementation. In the liver, 0.1% TAU decreased SOD but increased GSH-Px activity (P < 0.01). In duodenum, 42TAU decreased SOD activity (P < 0.05) while 0.1% TAU decreased GSH level and SOD activity (P < 0.05). In the hepatocytes, TAU treatment decreased (P < 0.05) the MDA and GSH contents, whereas increased SOD and GSH-Px activities (P < 0.05). Meanwhile, TAU treatment decreased (P < 0.05) the protein expression of Nrf2 while increase Keap1 expression. The mRNA expression of Nrf2, SOD1, SOD2, CAT, and GCLC were increased (P < 0.05) and GSR were decreased (P < 0.05) by 0.1% TAU. In the intestinal epithelial cells, TAU treatment decreased (P < 0.05) SOD activity, increased (P < 0.05) CAT activity, and decreased (P < 0.05) the mRNA and protein expression of Nrf2. In summary, partial substitution methionine for taurine (21-42%) has no influence on egg performance of hens. Taurine enhances the antioxidative capacity in hepatocyte but not in the enterocytes and if taurine could offer an improved effect on antioxidant capacity needs to be verified under oxidative stress-challenged conditions.

Heat stress modulates the disruptive effects of Eimeria maxima infection on the ileum nutrient digestibility, molecular transporters, and tissue morphology in meat-type chickens

Eimeria (E.) maxima is one of the most pathogenic Eimeria spp persistently invading the middle jejunum and ileum, damaging the intestinal mucosa of chickens. Heat stress (HS) is a common stressor and equally contributes to inflammation and oxidative stress. We investigated the effect of E. maxima infection and HS on ileal digestibility, mRNA expression of nutrient transporters, and ileal tissue morphology in broiler chickens. There were four treatment groups: thermoneutral control (TNc), thermoneutral infected (TNi), heat stress control (HSc), and heat stress infected (HSi), 6 replicates each of 10 birds per treatment. Chickens were fed a diet containing 0.2% TiO₂. At 6-day-post infection, ileal content and tissue were collected to quantify ileal digestibility of crude protein and fat, mRNA levels of nutrient transporters and histopathology. Growth and feed intake were reduced in all treatment groups, compared with the TNc. Contrary to expectation, the combination of two major stressors (E. maxima and HS) in the TNi group exhibited almost normal digestibility while only the TNi birds expressed severe digestibility depression, compared with the TNc group. The TNi group showed the lowest mRNA expression of the transporters: SGLT1, GLUT2-5-8-10-12, FABP1-2-6, and PEPT1 compared with the other treatment groups. The expression of the absorptive enterocytes’ gene markers (ACSL5, IAP, and SGLT1) supported by the ileal tissue morphology indicated that the TNi group had the highest enterocytic destruction. The expression of oxidative genes (iNOS and CYBB) dramatically increased only in the TNi group compared with the other treatment groups. Our results showed that exposing broiler chickens to HS can mitigate the disruptive effect of E. maxima on the ileal digestibility and absorption by limiting the parasite-induced tissue injury and suppressing the enterocytic inducible oxidative damage.

α-Ketoglutarate Improves Meiotic Maturation of Porcine Oocytes and Promotes the Development of PA Embryos, Potentially by Reducing Oxidative Stress through the Nrf2 Pathway

α-Ketoglutarate (α-KG) is a metabolite in the tricarboxylic acid cycle. It has a strong antioxidant function and can effectively prevent oxidative damage. Previous studies have shown that α-KG exists in porcine follicles, and its content gradually increases as the follicles grow and mature. However, the potential mechanism of supplementation of α-KG on porcine oocytes during in vitro maturation (IVM) has not yet been reported. The purpose of this study was to explore the effect of α-KG on the early embryonic development of pigs and the mechanisms underlying these effects. We found that α-KG can enhance the development of early pig embryos. Adding 20 μM α-KG to the in vitro culture medium significantly increased the rate of blastocyst formation and the total cell number. Compared with to that of the control group, apoptosis in blastocysts of the supplement group was significantly reduced. α-KG reduced the production of reactive oxygen species and glutathione levels in cells. α-KG not only improved the activity of mitochondria but also inhibited the occurrence of apoptosis. After supplementation with α-KG, pig embryo pluripotency-related genes (OCT4, NANOG, and SOX2) and antiapoptotic genes (Bcl2) were upregulated. In terms of mechanism, α-KG activates the Nrf2/ARE signaling pathway to regulate the expression of antioxidant-related targets, thus combating oxidative stress during the in vitro culture of oocytes. Activated Nrf2 promotes the transcription of Bcl2 genes and inhibits cell apoptosis. These results indicate that α-KG supplements have a beneficial effect on IVM by regulating oxidative stress during the IVM of porcine oocytes and can be used as a potential antioxidant for IVM of porcine oocytes.

In ovo threonine supplementation affects ileal gene expression of nutrient transporters in broilers inoculated post-hatch with Salmonella Enteritidis

The effect of in ovo threonine (Thr) supplementation on the ileal expression of glucose, peptide and amino acid transporters was assessed in Salmonella Enteritidis-challenged broiler chicks. At 17.5 days of incubation, fertile eggs were supplemented in the amniotic fluid with sterile saline or 3.5% threonine. Hatchlings were individually weighed, and Salmonella Enteritidis negative status was confirmed. At 2 days of age, half of the birds of each group were inoculated with sterile nutrient broth or Salmonella Enteritidis inoculum. Relative expression of sodium-dependent glucose transporter 1 (SGLT1), glucose transporter 2 (GLUT2), di- and tri-peptide transporter 1 (PepT1) and alanine, serine, cysteine, threonine transporter (ASCT1) was assessed at hatch, 2 and 9 days of age, i.e., before inoculation and 7 days post-inoculation (dpi). At 9 days of age (7dpi), threonine increased SGLT1 and GLUT2 expression, whereas GLUT2 expression decreased in Salmonella-challenged birds. There was a significant interaction between threonine and Salmonella for PepT1 and ASCT1. Threonine increased PepT1 expression only in non-challenged birds. In addition, in ovo supplementation increased expression of ASCT1 regardless of post-hatch inoculation; Salmonella inoculation resulted in decreased expression of ASCT1 only in supplemented birds. The results suggest that while intra-amniotic threonine administration in broiler embryos increases the expression of genes related to the absorption of monosaccharides and amino acids, Salmonella challenge may negatively affect the expression of protein related transporters in the ileum of broilers.

Effects of free and dipeptide forms of methionine supplementation on oxidative metabolism of broilers under high temperature

Our previous studies have shown that methionine supplementation could help to attenuate the effects of heat stress on the metabolism of broiler chickens. Here we investigated for the first time the effects of methionine supplementation in the form of DL-methionyl-DL-methionine on broilers subjected to heat stress during the growth phase. Broilers were divided into two groups; one group was reared under thermoneutral conditions and the other under continuous heat stress (30 ± 1 °C, 60% relative humidity). Both groups were subdivided into three dietary treatments: a methionine-deficient (MD) diet, a diet supplemented with free methionine (DL-M), and a diet supplemented with methionine dipeptide (DL-MM). Broilers raised under chronic heat stress had lower feed intake and weight gain than broilers raised under thermoneutral conditions (P < 0.05). There were no differences in animal performance between methionine-supplemented diets (DL-M and DL-MM). Heat-stressed birds had significantly higher heterophil/lymphocyte (H/L) ratio than thermoneutral birds. Under heat stress, broilers fed DL-M and DL-MM diets had lower H/L ratio than birds fed the MD diet. Higher concentrations of carbonylated proteins and lower concentration of reduced glutathione were observed in broilers raised under heat stress. In comparing heat-stressed broilers, we found that birds fed the DL-M diet had lower concentrations of thiobarbituric acid-reactive substances and carbonylated proteins than those fed the MD diet (P < 0.05). Higher expression of glutathione peroxidase (GPX) and glutathione synthetase (GSS) genes was observed in heat-stressed broilers (P < 0.05). Under heat stress, the MD diet increased GPX expression compared with other diets. Under thermoneutral conditions, the DL-M diet resulted in the highest GSS expression. There was a negative correlation between DNA methylation and GPX and GSS expression. Our results showed that supplementation of broiler diets with free methionine or methionine dipeptide may help attenuate the effects of heat stress through enhanced activation of genes related to the glutathione antioxidant system. Methionine effects were found for gene regulation, gene expression, and post-translational processing.

Supplementation with free methionine or methionine dipeptide improves meat quality in broilers exposed to heat stress

This study aimed to evaluate the effect of methionine dipeptide supplementation on the meat quality of broilers subjected to heat stress. A completely randomized 3 × 2 factorial design with four repetitions of each treatment was used. Three diets, unsupplemented (U), supplemented with methionine (M), and supplemented with methionine dipeptide (MM), were fed to 96 broilers subjected to thermal comfort (TC) or heat stress (HS, 32 °C for 24 h) conditions antemortem. Meat quality parameters, total antioxidant capacity (TAC), protein and lipid oxidation, and ryanodine receptor type 3 (RYR3) gene expression in breast muscle of 35-day-old broilers were evaluated. Methionine supplementation (M and MM) enhanced the nutritional quality of breast meat. Diet had a significant effect on breast meat pH, color (a*), and nitrogen and lipid contents. Interaction effects of diet and HS on TAC and protein oxidation were not observed. Diet and HS influenced lipid oxidation of breast meat after 7 days of refrigerated storage. High RYR3 expression was observed in breast meat of broilers subjected to heat stress and fed the U diet. No differences were observed between M and MM diets in any of the parameters evaluated. The results showed that both sources of methionine (M and MM) can be supplemented in broiler diets with beneficial effects on breast yield and meat nutritional quality. In addition, HS has made chickens more susceptible to biomolecule oxidation, and MM can potentiate chicken TAC. Further study is needed to better understand the effects of MM on broilers.

Heat stress management in poultry

High ambient temperature is one of the major causes of economic losses in the livestock industry. The poultry industry is an integral part of the livestock industry. It faces severe losses due to heat stress (HS). The adverse effects of HS can be seen on production performance, body temperature, intestinal health, appetite hormone regulation, immune responses and oxidative characteristics. It is important to monitor these parameters to identify the HS possessions during rearing so that timely action can be taken to minimize the adverse effects of high ambient temperature. Furthermore, the application of productive methods on farms is equally important. Several strategies have been suggested by researchers. Providing a suitable environment with selective rearing systems along with proper ventilation and hygiene is the basic requirement for all types of livestock reared for animal protein. Supplementation of appropriate feed additive could be useful for improving intestinal absorption and minimizing adverse effects of HS. Selection for breeding heat resistant birds also provide merits for improving the germplasm of the strains. Early age thermal conditioning also helps in developing resistance for HS. The most recent advancement is the supplementation of active substances during incubation. It is expected that these methods may have a potential impact on the poultry industry for creating thermotolerance in the newly hatched chicks. This review highlights the major issues concerning chicken health and suggests the measures to be adopted following the increase in environmental temperature.

Maternal dietary linoleic acid altered intestinal barrier function in domestic pigeons (Columba livia)

Linoleic acid (LA) is predominantly essential for poultry. Poultry lacking LA show retarded growth and reduced disease resistance. Intestinal barrier function plays an important role in pigeon squab growth, whereas research on the effects of LA on intestinal health in altrices is scant. Considering that squabs are fed by their parents, the study aimed to explore the effects of maternal dietary LA on intestinal morphology, tight junction proteins, immune cytokines and microbial flora in squabs. A completely randomised design with a control group, 1 % LA supplementation group, 2 % LA supplementation group and 4 % LA supplementation group was used. Six squabs from each treatment were randomly sampled at 21 d post-hatching. The results indicated that LA supplementation improved intestinal morphology, as reflected by increased villus height, villus area and the ratio of villi to crypts. Also, 1 % LA supplementation elevated the density of goblet cells in the intestine and strengthened tight junctions by up-regulating claudin-3 and occludin gene expression but down-regulating claudin-2 gene expression. Moreover, 1 % LA supplementation reduced the secretion of proinflammatory cytokines and partly increased anti-inflammatory cytokines. The intestinal microbial diversity in the 1 % LA supplementation group was higher than that in the other groups. As beneficial bacteria, Butyrivibrio was the biomarker of 1 % LA supplementation. However, excessive (4 %) LA supplementation led to adverse impacts on intestinal immunity and microbiota. In conclusion, maternal dietary LA might alter intestinal barrier function in pigeon squabs in a dose-dependent manner. Supplementation with 1 % LA was suggested in parental pigeons.

Nutritional significance of amino acids, vitamins and minerals as nutraceuticals in poultry production and health - a comprehensive review

Nutraceuticals have gained immense importance in poultry science recently considering the nutritional and beneficial health effects of their constituents. Besides providing nutritional requirements to birds, nutraceuticals have beneficial pharmacological effects, for example, they help in establishing normal physiological health status, prevent diseases and thereby improve production performance. Nutraceuticals include amino acids, vitamins, minerals, enzymes, etc. which are important for preventing oxidative stress, regulating the immune response and maintaining normal physiological, biochemical and homeostatic mechanisms. Nutraceuticals help in supplying nutrients in balanced amounts for supporting the optimal growth performance in modern poultry flocks, and as a dietary supplement can reduce the use of antibiotics. The application of antibiotic growth enhancers in poultry leads to the propagation of antibiotic-resistant microbes and drug residues; therefore, they have been restricted in many countries. Thus, there is a demand for natural feed additives that lead to the same growth enhancement without affecting the health. Nutraceuticals substances have an essential role in the development of the animals' normal physiological functions and in protecting them against infectious diseases. In this review, the uses of amino acids, vitamins and minerals as well as their mode of action in growth promotion and elevation of immune system are discussed.

Partial or complete replacement of fishmeal with fermented soybean meal on growth performance, fecal composition, and meat quality in broilers

The current study was aimed to examine the effect of partial or complete replacement of fishmeal (FM) with fermented soybean meal (FSBM) on growth performance, fecal composition, and meat quality in broiler chickens. A total number of 240 one-day-old broiler chicks were randomly allotted into four dietary treatments with six replications and ten birds per one pen. Dietary treatments were followed as; 1) Diet incorporated with 4% FM without FSBM (Control), 2) Diet incorporated with 3% FM and 2% FSBM (FSBM2), 3) Diet incorporated with 2% FM and 3% FSBM (FSBM3) and 4) Diet incorporated with 4% FSBM without FM (FSBM4). Body weight and feed intake were recorded weekly for 35 days of the experimental period. Moreover, fecal samples were collected to evaluate moisture, ash, nitrogen, calcium and phosphorus content on day 21 post-hatch. On day 35, two birds were sacrificed from each pen to measure meat quality parameters and visceral organ weights. Results revealed that, no dietary treatment effect (p > 0.05) was observed either in both body weight or average daily gain of broilers within the entire experimental period while broilers fed FSBM2 increased (p < 0.05) average daily feed intake by 10.07% whereas FSBM4 improved (p < 0.05) feed efficiency ratio by 8.45% compared to birds fed other dietary treatments on day 7 post-hatch. Besides, birds fed FSBM3 obtained the improved (p < 0.05) feed conversion ratio over the birds fed control diet by 7.51% from hatch to day 35 post-hatch (1.60 vs. 1.73). Nevertheless, no difference (p > 0.05) was detected on visceral organ weight, proximate composition and physicochemical characteristics of meat while broilers offered FSBM4 obtained the lowest (p < 0.05) calcium and phosphorous in faces (2.27% and 1.21% respectively) over those offered control feed and other FSBM treatments. In conclusion, FSBM would be a better replacement for ousting FM partially or completely in broiler diet as it did not impair the growth performance and meat quality while reducing the calcium and phosphorous excretion in broilers for 35 days post-hatch.

Quercetin promotes in vitro maturation of oocytes from humans and aged mice

Maternal fertility declines irreversibly with aging, and advanced maternal age is mostly related to impaired oocyte quality. The flavonol compound quercetin is considered to be an anti-aging agent due to its cytoprotective actions as an antioxidant. However, its role and mechanisms on aged oocytes are unclear. In this study, the quercetin promotes in vitro maturation (IVM) and early embryonic development of oocytes from aged mice. It is extended these findings in human oocytes, showing that quercetin promotes the IVM rate by 19.6% and increases the blastocyst formation rate by 15.5% compared to untreated controls. The overall oocyte quality of aged mice is improved by quercetin treatment, assessed as spindle/chromosome morphology and cortical granule distribution. Mitochondria is the primary endogenous source of age-related oxidative stress, and an RNA-seq analysis of quercetin-treated oocytes reveals molecular insights including scavenged mitochondrial-ROS, reduced apoptosis, and improved autophagy. Further, this study demonstrates that quercetin reduces ROS via SIRT3-mediated acetylation of SOD2's K68 residue. Thus, beyond demonstrating that quercetin confers beneficial mitochondria-related impacts in aged oocytes, this study illustrates a potential strategy to prevent or delay oocyte aging and to improve success rates of assisted human reproductive technologies (ART).

The effects of total sulfur amino acids on the intestinal health status of broilers challenged with Eimeria spp

This study evaluated the effects of total sulfur amino acid (TSAA) levels on the performance and intestinal health of broilers challenged with Eimeria spp. A total of 432 one-day-old off-sex Cobb 500 male chicks were randomly assigned to a 3 × 2 factorial arrangement (6 replicates/12 birds), with diets and Eimeria challenge as the main factors. The diets were as follows: 70% (no methionine [Met] supplementation), 85, and 100% TSAA, supplemented with L-Met. At day 14, the challenged birds (n = 216) were orally gavaged with a pool of Eimeria acervulina, Eimeria maxima, and Eimeria tenella sporulated oocysts, and the unchallenged birds (n = 216) received water. At 6 and 12 D post inoculation (dpi), performance and intestinal health were evaluated. The challenge, regardless of diets, significantly impaired the performance, intestinal villi height, villus-to-crypt ratio, and ileal digestibility of dry matter, energy, and crude protein (CP) and modulated the tight junction protein (TJP) expression throughout the experiment. Moreover, the superoxide dismutase activity was increased, whereas the reduced glutathione (GSH)-to-oxidized glutathione (GSSG) ratio was decreased by the challenge at 6 dpi. Regardless of the challenge, the 70% TSAA diet reduced the body weight and feed intake in all phases, whereas the ileal digestibility of CP was higher in birds fed with the 70% TSAA diet than in those fed with the 100% TSAA diet at 6 dpi. No major differences were observed among the diets with regard to the intestinal histomorphology and TJP expression, and birds fed with the 100% TSAA diet had the highest GSH concentration at 12 dpi. Few interactions were observed, and the Met supplementation counteracted the negative effects of the Eimeria challenge on GSH concentration when 85 and 100% of TSAA levels were reached. Overall, the Eimeria challenge had a negative impact on growth and intestinal health. Moreover, the supplementation of L-Met until either 85 or 100% of TSAA levels were reached was enough to assure good performance and intestinal health in birds challenged or not challenged with Eimeria spp.

The effects of L-Arginine supplementation on growth performance and intestinal health of broiler chickens challenged with Eimeria spp

This study evaluated the effects of varying levels of L-arginine (Arg) on performance and intestinal health of broilers challenged with Eimeria. Cobb 500 male chicks (n = 720) were randomly distributed in a 5 × 2 factorial arrangement (6 replicates/12 birds). The main factors were Arg levels (1.04, 1.14, 1.24, 1.34, 1.44%) and challenge or non-challenge with Eimeria. At day 12, in the challenge group, each bird received orally 12,500 Eimeria maxima, 12,500 Eimeria tenella, and 62,500 Eimeria acervulina sporulated oocysts. At 5 d postinfection (dpi), intestinal permeability was measured. At 6 and 14 dpi, performance, intestinal histomorphology, nutrient digestibility, tight junction protein (TJP) gene expression, and antioxidant markers were evaluated. Few interactions were found, and when significant, the supplementation of Arg did not counteract the negative effects of Eimeria challenge. Challenge, regardless of Arg level, increased intestinal permeability, although the expression of Claudin-1, a TJP, was upregulated. At 6 dpi, the antioxidant system was impaired by the challenge. Moreover, growth performance, intestinal histomorphology, and nutrient digestibility were negatively affected by challenge at 6 and 14 dpi. Regardless of challenge, from 0 to 14 dpi, birds fed 1.44% showed higher weight gain than 1.04% of Arg, and birds fed 1.34% showed lower feed conversion than 1.04% of Arg. At 5 dpi, intestinal permeability was improved in birds fed 1.34% than 1.04% of Arg. Moreover, 1.34% of Arg upregulated the expression of the TJP Zonula occludens-1 (ZO-1) as compared with 1.24 and 1.44% of Arg at 6 dpi. At 14 dpi, 1.44% of Arg upregulated the expression of ZO-1 and ZO-2 compared with 1.24 and 1.34% of Arg. The nutrient digestibility was quadratically influenced by Arg, whereas the antioxidant markers were unaffected. Thus, the challenge with Eimeria had a negative impact on growth and intestinal health. The dietary supplementation of levels ranging from 1.24 to 1.44% of Arg showed promising results, improving overall growth, intestinal integrity, and morphology in broilers subjected or not to Eimeria challenge.

Dietary supplementation with free methionine or methionine dipeptide improves environment intestinal of broilers challenged with Eimeria spp

This study examined the influence of a diet enriched with free methionine (dl-Met) or methionine dipeptide (dl-MMet) on the intestinal health of Eimeria-challenged (EC) and unchallenged (UC) broilers. A non-supplemented, methionine-deficient diet (NS) was used as control. Treatments were arranged in a 2 × 3 factorial completely randomized design with eight replications. Broilers in the EC group were infected with sporulated oocysts of Eimeria spp. (E. acervulina, E. maxima, E. praecox, and E. mitis) at 14 d of age. Performance analysis, light and electron microscopy of the jejunum, analysis of genes related to apoptosis and cell proliferation in the jejunum, and blood tests were performed at 6 days post-inoculation (dpi). EC broilers had poorer performance than UC broilers, regardless of diet (P < 0.001). Broilers fed the dl-Met diet had greater weight gain (P = 0.004) and lower feed conversion ratio (P = 0.019) than broilers fed other diets. Jejunal sections from EC broilers fed the NS diet showed short (P = 0.001) and wide villi (P < 0.001) with increased crypt depth (P < 0.001) and reduced villus / crypt ratio (P = 0.001), jejunal absorptive surface area (P < 0.001), number of neutral goblet cells (Eimeria challenge: P = 0.048; diet P = 0.016), and mucin 2 (MUC2) gene expression (P = 0.018). EC birds fed the dl-MMet diet had higher enterocyte height (P < 0.001). Birds fed the dl-MMet diet had low lamina propria width (P = 0.009). UC broilers fed the dl-Met diet had the highest number of acidic goblet cells (P = 0.005), whereas EC broilers assigned the dl-MMet diet showed the highest number of intraepithelial lymphocytes (P = 0.033). Reduced expression of caspase-3 (CASP3) (P = 0.005), B-cell lymphoma 2 (BCL2) (P < 0.001), mechanistic target of rapamycin (MTOR) (P < 0.001), and ribosomal protein S6 kinase B1 (RPS6KB1) (P < 0.001) genes was observed in EC animals. MTOR expression levels were highest in birds fed the dl-MMet diet (P = 0.004). Plasma activities of aspartate aminotransferase (AST) was influenced by both diet (P = 0.002) and Eimeria challenge (P = 0.005), with EC broilers assigned the NS diet showing the highest levels. EC broilers fed the NS diet had higher creatine kinase (CK) activity (P = 0.049). EC broilers had lower plasma uric acid (P = 0.004) and higher serum mucoproteins level (P < 0.001). These results indicate that methionine dipeptide supplementation is able to mitigate the harmful intestinal effects of Eimeria spp. in broilers.

Dietary pterostilbene supplementation attenuates intestinal damage and immunological stress of broiler chickens challenged with lipopolysaccharide

The present study explored the potential effect of pterostilbene as a prophylactic treatment on the lipopolysaccharide (LPS)-induced intestinal injury of broiler chickens by monitoring changes in mucosal injury indicators, redox status, and inflammatory responses. In total, 192 one-day-old male Ross 308 broiler chicks were randomly divided into four groups. This trial consisted of a 2 × 2 factorial design with a diet factor (supplemented with 0 or 400 mg/kg pterostilbene from 1 to 22 d of age) and a stress factor (intraperitoneally injected with saline or LPS at 5.0 mg/kg BW at 21 da of age). The results showed that LPS challenge induced a decrease in BW gain (P < 0.001) of broilers during a 24-h period postinjection; however, this decrease was prevented by pterostilbene supplementation (P = 0.031). Administration of LPS impaired the intestinal integrity of broilers, as indicated by increased plasma diamine oxidase (DAO) activity (P = 0.014) and d-lactate content (P < 0.001), reduced jejunal villus height (VH; P < 0.001) and the ratio of VH to crypt depth (VH:CD; P < 0.001), as well as a decreased mRNA level of jejunal tight junction protein 1 (ZO-1; P = 0.002). In contrast, pterostilbene treatment increased VH:CD (P = 0.018) and upregulated the mRNA levels of ZO-1 (P = 0.031) and occludin (P = 0.024) in the jejunum. Consistently, pterostilbene counteracted the LPS-induced increased DAO activity (P = 0.011) in the plasma. In addition, the LPS-challenged broilers exhibited increases in nuclear accumulation of nuclear factor kappa B (NF-κB) p65 (P < 0.001), the protein content of tumor necrosis factor α (P = 0.033), and the mRNA abundance of IL-1β (P = 0.042) and nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3; P = 0.019). In contrast, pterostilbene inhibited the nuclear translocation of NF-κB p65 (P = 0.039) and suppressed the mRNA expression of IL-1β (P = 0.003) and NLRP3 (P = 0.049) in the jejunum. Moreover, pterostilbene administration induced a greater amount of reduced glutathione (P = 0.017) but a lower content of malondialdehyde (P = 0.023) in the jejunum of broilers compared with those received a basal diet. Overall, the current study indicates that dietary supplementation with pterostilbene may play a beneficial role in alleviating the intestinal damage of broiler chicks under the conditions of immunological stress.