16S ribosomal RNA sequencing reveals a modulation of intestinal microbiome and immune response by dietary L-theanine supplementation in broiler chickens

The protective effect of L-theanine addition to a cryoprotectant on the storage viability of lactic acid bacteria

Lactic acid bacteria (LAB) that metabolize sugars to obtain energy and produce a large amount of lactate through the process are well known for their benefits. However, they can be used on a large scale only when good storage stability is guaranteed. The vitality and stability of several LAB strains were effectively protected in this investigation by L-theanine at 1% of the appropriate concentration (Lactiplantibacillus plantarum MG5023, Enterococcus faecium MG5232, Lactococcus lactis MG4668, Streptococcus thermophilus MG5140, and Bifidobacterium animalis subsp. lactis MG741). The inclusion of L-theanine as a protective agent significantly enhanced the viability of all strains throughout the freeze-drying process compared to that of the non-coated probiotics. The efficacy of L-theanine in improving bacterial stability and survivability was evaluated using accelerated stability tests, gastrointestinal (GI) tract survivability tests, and adhesion assays with intestinal epithelial cells. The cell surface was covered with substances including L-theanine, according to morphological findings, providing efficient defense against a variety of external stresses. Therefore, by exerting anti-freezing and anti-thawing properties, the adoption of L-theanine as a new and efficient protective agent may improve the stability and viability of a variety of probiotics.

Effect of bioactive compounds in processed Camellia sinensis tea on the intestinal barrier

The human intestinal tract plays a pivotal role in safeguarding the body against noxious substances and microbial pathogens by functioning as a barrier. This barrier function is achieved through the combined action of physical, chemical, microbial, and immune components. Tea (Camellia sinensis) is the most widely consumed beverage in the world, and it is consumed and appreciated in a multitude of regions across the globe. Tea can be classified into various categories, including green, white, yellow, oolong, black, and dark teas, based on the specific processing methods employed. In recent times, there has been a notable surge in scientific investigation into the various types of tea. The recent surge in research on tea can be attributed to the plethora of bioactive compounds it contains, including polyphenols, polysaccharides, pigments, and theanine. The processing of different teas affects the active ingredients to varying degrees, resulting in a range of chemical reactions and the formation of different types and quantities of ingredients. The bioactive compounds present in tea are of great importance for the maintenance of the integrity of the intestinal barrier, operating through a variety of mechanisms. This literature review synthesizes scientific studies on the impact of the primary bioactive compounds and different processing methods of tea on the intestinal barrier function. This review places particular emphasis on the exploration of the barrier repair and regulatory effects of these compounds, including the mitigation of damage to different barriers following intestinal diseases. Specifically, the active ingredients in tea can alleviate damage to physical barriers and chemical barriers by regulating barrier protein expression. At the same time, they can also maintain the stability of immune and biological barriers by regulating the expression of inflammatory factors and the metabolism of intestinal flora. This investigation can establish a strong theoretical foundation for the future development of innovative tea products.

Mechanisms of Heat Stress on Neuroendocrine and Organ Damage and Nutritional Measures of Prevention and Treatment in Poultry

Heat stress (HS) due to high temperatures has adverse effects on poultry, including decreased feed intake, lower feed efficiency, decreased body weight, and higher mortality. There are complex mechanisms behind heat stress in poultry involving the neuroendocrine system, organ damage, and other physiological systems. HS activates endocrine glands, such as the pituitary, adrenal, thyroid, and gonadal, by the action of the hypothalamus and sympathetic nerves, ultimately causing changes in hormone levels: HS leads to increased corticosterone levels, changes in triiodothyronine and thyroxine levels, decreased gonadotropin levels, reduced ovarian function, and the promotion of catecholamine release, which ultimately affects the normal productive performance of poultry. Meanwhile, heat stress also causes damage to the liver, lungs, intestines, and various immune organs, severely impairing organ function in poultry. Nutrient additives to feed are important measures of prevention and treatment, including natural plants and extracts, probiotics, amino acids, and other nutrients, which are effective in alleviating heat stress in poultry. Future studies need to explore the specific mechanisms through which heat stress impacts the neuroendocrine system in poultry and the interrelationships between the axes and organ damage so as to provide an effective theoretical basis for the development of preventive and treatment measures.

Salinity negatively correlates with the production and immunity of chicken: A molecular insight for food security and safety issues

Salinity intrusion into the freshwater system due to climate change and anthropogenic activities is a growing global concern, which has made humans and domesticated animals more susceptible to diseases, resulting in less productivity. However, the effects of salinity on domesticated and wild birds, especially in terms of production and immunity, have not been fully elucidated yet. Therefore, this study was designed to examine the effects of salinity on the production and immunity of birds and the mechanisms by which immunity is compromised. Broiler chicks were subjected to different concentrations of salty water (control = normal water, treatment = 5 g/L, treatment = 10 g/L, and treatment = 15 g/L). The collected blood and organs from different groups of broilers were biochemically and histopathologically examined. Birds in salt-treated groups consumed significantly less feed than the control group, while the feed conversion ratio (FCR) was significantly higher. Body weight gain was significantly lower in salt-treated groups compared to control. Serum analysis revealed a lower systemic antibody titer in the salt-treated groups compared to the control. Primary lymphoid organs (thymus and bursa of Fabricius) were reduced in size in the salt-treated group due to cellular migration and depletion from these organs. Importantly, most of the parenchyma of lymphoid organs was replaced with fibrotic tissue. Gut microbes, Escherichia coli (E. coli) and Salmonella spp., from salt-treated groups, showed less viability but developed antibiotic resistance. Levels of salinity were significantly and negatively correlated with feed intake, body weight gain, antibody titer, lymphoid organ size, and viable count of gut microbes, while FCR, fibrosis of lymphoid organs, and antibiotic resistance were significant positively correlated. In conclusion, increased salinity is a possible threat to food security and safety as it decreases body weight gain, reduces immunity, and influences the development of multi-drug resistance in gut microbes.

Dietary supplementation with Lactium and L-theanine alleviates sleep disturbance in adults: a double-blind, randomized, placebo-controlled clinical study

Introduction

The use of natural products for the treatment of sleep disturbances is increasing owing to the side effects and limitations of traditional sleep therapy. Moreover, recent studies have shown a significant correlation between sleep quality and gut microbiota composition. This study aimed to assess the impact of LTC-022, a commercially available dietary supplement containing Lactium and L-theanine, on enhancing sleep quality.

Methods

Forty participants experiencing sleep discomfort were enrolled in a double-blind randomized controlled trial, wherein they received LTC-022 or a placebo orally for 8 weeks. The effects of treatment on sleep quality were assessed using the Pittsburgh Sleep Quality Index and Insomnia Severity Index. To comprehensively evaluate changes in sleep patterns, various parameters were evaluated, including the time in bed (TIB), total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), wake after sleep onset (WASO) counts, and bedtime. These parameters were derived from daily sleep logs recorded over the 8-week study period, categorized into weekdays and weekends. Stool samples were analyzed for microbiome composition. The V4 region of bacterial 16S rRNA genes was amplified using specific primers (515F and 806R) and targeted for analysis. Microbial diversity, including operational taxonomic units, the Shannon and Chao indices, the Firmicutes/Bacteroidetes (F/B) ratio, and the variety of bacterial taxa, was assessed.

Results

No significant differences were observed in sleep quality and insomnia scale characteristics between the two groups. In-depth analysis using sleep diaries showed that WASO counts after 8 weeks and bedtime after 4 weeks showed significant differences between the LTC-022 and control groups. In the LTC-022 group, significant differences were observed in the increase in TST, decrease in SOL, increase in SE, decrease in WASO counts, and earlier bedtime. Microbiome analysis revealed that the abundance of the genera Blautia and Ruminococcus increased in fecal samples from the LTC-022 group.

Conclusion

These results suggest that continuous LTC-022 intake has a beneficial effect on maintaining sleep duration and an appropriate bedtime. Additionally, changes in the gut microbiota may be linked to changes in sleep patterns resulting from the consumption of Lactium and L-theanine.

Clinical trial registration

https://cris.nih.go.kr/cris/search/detailSearch.do/22841, KCT0007750.

Modulation of chicken gut microbiota for enhanced productivity and health: A review

Microbiota in the digestive tract has become an interesting topic for researchers in recent years. The profile of chicken digestive tract microbiota and its relationship with health and production efficiency have become basic data for modulating the diversity and abundance of the digestive tract microbiota. This article reviews the techniques used to analyze the diversity, role, and function of the gastrointestinal microbiota and the mechanisms by which they are modulated. The gut microbiota plays an important role in animal production, especially during feed digestion and animal health, because it interacts with the host against pathogens. Feed modulation can be a strategy to modulate gut composition and diversity to increase production efficiency by improving growth conditions.

Promising future of citrus waste into fermented high-quality bio-feed in the poultry nutrition and safe environment

Essential oils (EO), ascorbic acid, sugars, carotenoids, flavonoids, dietary fiber, polyphenols, and trace minerals are found in citrus residue. It gives animals energy and promotes health. On a dry matter basis, the citrus pulp is composed of 7% crude protein, 14% crude fiber, 21.6% nitrogen detergent fiber, 2.5% fat, 24.4% total sugars, and 12.1% ME MJ/kg. It has been reported that the natural antioxidant content of citrus pulp has a beneficial effect on growth and microbial and immunological parameters. The literature indicates that the ultimate weight and weight gain of poultry are significantly (P > 0.05) greater with 7.5% inclusion. Growing knowledge of the health benefits of lactic acid bacteria (LAB) in producing beneficial metabolites has led to interest in developing LAB-containing products for use in biofeed businesses. The consumption of fermented citrus residue significantly decreased blood cholesterol levels. Fermentation results in the production of many compounds (including organic acids, exopolysaccharides, bioactive peptides, phenolic compounds, and gamma-aminobutyric acid), which have many multidimensional functions for maintaining the health and well-being of poultry. During fermentation, the pH may quickly decrease, and harmful bacterial and fungal organisms may be substantially retarded at the early stage of ensiling. The published literature has shown that the fermentation of citrus waste with different probiotic strains, such as Lactobacillus acidophilus, Limosilactobacillus fermentum, Lactiplantibacillus plantarum, Pediococcus pentocaseus, and Lacticaseiobacillus paracasei, in the diet has fantastic effects on the conversion of citrus waste into fermented high-quality feed with extended shelf life and sensory value. Citrus waste lactic acid fermentation may be a viable option for producing nutritional biofeed for poultry, but there is a lack of related research on poultry, so more research on food-grade bacterial fermentation is needed.

The Impact of Essential Amino Acids on the Gut Microbiota of Broiler Chickens

The research involving the beneficial aspects of amino acids being added to poultry feed pertaining to performance, growth, feed intake, and feed conversion ratio is extensive. Yet currently the effects of amino acids on the gut microbiota aren't fully understood nor have there been many studies executed in poultry to explain the relationship between amino acids and the gut microbiota. The overall outcome of health has been linked to bird gut health due to the functionality of gastrointestinal tract (GIT) for digestion/absorption of nutrients as well as immune response. These essential functions of the GI are greatly driven by the resident microbiota which produce metabolites such as butyrate, propionate, and acetate, providing the microbiota a suitable and thrive driven environment. Feed, age, the use of feed additives and pathogenic infections are the main factors that have an effect on the microbial community within the GIT. Changes in these factors may have potential effects on the gut microbiota in the chicken intestine which in turn may have an influence on health essentially affecting growth, feed intake, and feed conversion ratio. This review will highlight limited research studies that investigated the possible role of amino acids in the gut microbiota composition of poultry.

The protective effect of L-theanine on the intestinal barrier in heat-stressed organisms

Heat stress caused by heatwaves, extreme temperatures, and other weather can damage the intestinal barrier of organisms. L-Theanine (LTA) attenuates heat stress-induced oxidative stress, inflammatory responses, and impaired immune function, but its protective effect on the intestinal barrier of heat-stressed organisms is unclear. In this study, low (100 mg kg-1 d-1), medium (200 mg kg-1 d-1), and high (400 mg kg-1 d-1) dosages of LTA were used in the gavage of C57BL/6J male mice that were experimented on for 50 d. These mice were subjected to heat stress for 2 h d-1 at 40 ± 1 °C and 60 ± 5% RH in the last 7 d. LTA attenuated the heat stress-induced decreases in body mass and feed intake, and the destruction of intestinal villi and crypt depth; reduced the serum levels of FITC-dextran and D-LA, as well as the DAO activity; and upregulated the colonic tissues of Occludin, Claudin-1, and ZO-1 mRNA and occludin protein expression. The number of goblet cells in the colon tissue of heat-stressed organisms increased in the presence of LTA, and the expression levels of Muc2, Muc4 mRNA, and Muc2 protein were upregulated. LTA increased the abundance of Bifidobacterium and Turicibacter, and decreased the abundance of Enterorhabdus and Desulfovibrio in the intestinal tract of heat-stressed organisms and restored gut microbiota homeostasis. LTA promoted the secretion of IL-4, IL-10, and sIgA and inhibited the secretion of TNF-α and IFN-γ in the colon of heat-stressed organisms. The expressions of Hsf1, Hsp70, Hsph1, TLR4, P38 MAPK, p-P65 NF-κB, MLCK mRNA, and proteins were downregulated by LTA in the colon of heat-stressed organisms. These results suggest that LTA protects the intestinal barrier in heat-stressed organisms by modulating multiple molecular pathways. Therefore, this study provides evidence on how tea-containing LTA treatments could be used to prevent and relieve intestinal problems related to heat stress.

L-Theanine alleviates heat stress through modulation of gut microbiota and immunity

BACKGROUND

Heat stress (HS) damages the intestines, disrupting gut microbiota and immune balance. l-Theanine (LTA), found in tea, alleviates oxidative stress and cell apoptosis under HS; however, its effects on gut microbiota and immunity under HS remain unclear. To investigate this, we administered LTA doses of 100, 200, and 400 mg·kg-1 ·d-1 to C57BL/6J mice. On day 44, the model group and LTA intervention group were subjected to continuous 7-day HS treatment for 2 h per day.

RESULTS

The results demonstrated that LTA intervention improved food intake, body weight, and intestinal epithelium, and reduced the water intake of heat-stressed mice. It increased the abundance of Turicibacter, Faecalibaculum, Bifidobacterium, and norank_f_Muribaculaceae, while reducing that of Lachnoclostridium and Desulfovibrio. LTA intervention also increased the concentrations of amino acid and lipid metabolites, regulated macrophage differentiation stimulated by gut microbiota and metabolites, reduced the antigen presentation by macrophages to the specific immune system, promoted B-cell differentiation and sIgA secretion, inhibited pro-inflammatory factors, and enhanced intestinal defense. Mechanistically, LTA downregulated heat shock protein 70 expression and the TLR4/NF-κB/p38 MAPK signaling pathway, restoring gut microbiota and immune balance.

CONCLUSION

We suggest that LTA can alleviate HS by modulating gut microbiota, metabolites, and immunity, indicating its potential as a natural active ingredient for anti-HS food products. © 2023 Society of Chemical Industry.

The butyrate-producing and spore-forming bacterial genus Coprococcus as a potential biomarker for neurological disorders

The host-intestinal microbiome interaction has gained much scientific attention in the past two decades, boosted by advances in DNA sequencing and cultivation techniques. An accumulating amount of evidence shows that gut microbes play crucial roles in gut homeostasis, immune system education, and are associated with quality-of-life indicators. Beneficial health factors are associated with the digestion of dietary fibres in the colon and the subsequent production of short-chain fatty acids, including acetate, propionate, and butyrate. Coprococcus is a butyrate-producing genus in the phylum Firmicutes, and its abundance is inversely correlated with several neuropsychological and neurodegenerative disorders. Case-control studies provide strong evidence of decreased abundance of Coprococcus spp. in depressed individuals. The species Coprococcus eutactus has the unique capacity to use two separate pathways for butyrate synthesis and has been found to be depleted in children with delayed language development and adults with Parkinson's disease. The combined literature on Coprococcus and the gut microbiota-brain axis points towards enhanced butyrate production and reduced colonisation of pathogenic clades as factors explaining its association with health effects. The genus Coprococcus is a promising candidate for a mental health biomarker and an interesting lead for novel dietary-based preventive therapies for specific neurological disorders.

L-theanine attenuates porcine intestinal tight junction damage induced by LPS via p38 MAPK/NLRP3 signaling in IPEC-J2 cells

L-theanine is a natural bioactive component in tea leaves and has anti-inflammatory effects. The study aimed to investigated the effects and underlying mechanisms of L-theanine on lipopolysaccharide (LPS)-induced intestinal tight junction damage in IPEC-J2 cells. Results showed that LPS induced tight junction damage by increasing reactive oxygen species production and lactate dehydrogenase (LDH) release and decreasing the mRNA expression of tight junction proteins related genes zonula occludens-1 (ZO-1, also known as Tjp1), Occludin and Claudin-1, while L-theanine reversed such an effect and attenuated the increase of p38 mitogen-activated protein kinase (p38 MAPK) mRNA expression. The p38 MAPK inhibitor (SB203580) attenuated the mRNA expression of nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (Nlrp3) inflammasome and interleukin-1β (Il-1β), and increased the mRNA expression of Tjp1, Occludin and Claudin-1, which showed a similar effect with L-theanine. In addition, NLRP3 inhibitor MCC950 attenuated the Il-1β expression and LDH release, while increased the expression of tight-junction protein-related genes. In conclusion, L-theanine could protect LPS-induced intestinal tight junction damage by inhibiting the activation of p38 MAPK-mediated NLRP3 inflammasome pathway.

L-Theanine and Immunity: A Review

L-theanine (N-ethyl-γ-glutamine) is the main amino acid in tea leaves. It not only contributes to tea flavor but also possesses several health benefits. Compared with its sedative and calming activities, the immunomodulatory effects of L-theanine have received less attention. Clinical and epidemiological studies have shown that L-theanine reduces immunosuppression caused by strenuous exercise and prevents colds and influenza by improving immunity. Numerous cell and animal studies have proven that theanine plays an immunoregulatory role in inflammation, nerve damage, the intestinal tract, and tumors by regulating γδT lymphocyte function, glutathione (GSH) synthesis, and the secretion of cytokines and neurotransmitters. In addition, theanine can be used as an immunomodulator in animal production. This article reviews the research progress of L-theanine on immunoregulation and related mechanisms, as well as its application in poultry and animal husbandry. It is hoped that this work will be beneficial to future related research.

L-Theanine alleviates heat stress-induced impairment of immune function by regulating the p38 MAPK signalling pathway in mice

With the current trend of global warming, heat stress-induced impairment could seriously endanger human health. L-Theanine is a non-protein amino acid in tea with various biological activities, including immunoregulatory, anti-anxiety, and anti-oxidation. However, its effect on immune function under heat stress and the underlying mechanism are currently unclear. In this study, male BALB/c mice were used as experimental objects to explore the effect of L-theanine on heat stress-induced changes in immune function and its mechanism. Three doses of L-theanine were used: low (100 mg kg^-1 d^-1), medium (200 mg kg^-1 d^-1), and high (400 mg kg^-1 d^-1). Treatment with L-theanine could attenuate the heat stress-induced reductions in body weight and feed intake in mice, alleviate damage in the liver and jejunum, and inhibit the inflammatory factors IL-6, IL-1β, and TNF-α. Aspartate aminotransferase and alanine transaminase activity levels and the malondialdehyde content decreased, while the IgA, IgM, and IgG contents increased in response to L-theanine. It is possible that L-theanine affects the P38 signalling pathway and inhibits the increase in p-P65/P65 caused by the overexpression of HSP27 and regulation of PPAR-γ and Foxp3 proteins, thereby alleviating immune dysfunction caused by heat stress.

Effect of feeding bioactive compounds identified from plant extracts (4-hexylresorcinol, 7-hydroxycoumarin, and gamma-octalactone) on the productivity and quality of broiler meat

Background and Aim

Secondary bioactive compounds of medicinal plants exert anti-inflammatory, antimicrobial, antioxidant, and metabolism-modulating effects. This study aimed to investigate the effect of feeding 4-hexylresorcinol, as well as its combinations with gamma-octalactone and 7-hydroxycoumarin, on the digestibility of dietary nutrients, weight gain, and quality characteristics of the meat and liver of Arbor Acres broiler chickens.

Materials and Methods

The following feeding scheme was applied on the chickens: Control, basal diet (BD); I experimental, BD + 4-hexylresorcinol at 0.5 mg/kg of live weight per day; II experimental, BD + 4-hexylresorcinol + gamma-octalactone at 0.4 mg/kg of live weight per day; III experimental, BD + 4-hexylresorcinol + 7-hydroxycoumarin at 0.1 and 0.15 mg/kg of live weight per day; and IV experimental, BD + 4-hexylresorcinol + gamma-octalactone + 7-hydroxycoumarin at 0.05, 0.15, and 0.01 mg/kg of live weight per day.

Results

Chickens in I, II, and IV experimental groups at the age of 35 days showed superior live weight than chickens in the control group. Supplementation with all the tested additives, except the combination 4-hexylresorcinol + 7-hydroxycoumarin, significantly increased the digestibility coefficients of dietary nutrients. Supplementation with the combinations 4-hexylresorcinol + gamma-octalactone and 4-hexylresorcinol + gamma-octalactone + 7-hydroxycoumarin significantly increased the amount of fat in the pectoral muscles. However, the mass fraction of fat in the thigh muscles of broiler chickens decreased in II, III, and IV experimental groups. The pectoral muscles of broiler chickens in experimental Group IV contained small amounts of lysine, tyrosine, histidine, leucine-isoleucine, methionine, valine, proline, threonine, serine, alanine, and glycine. Supplementation with pure 4-hexylresorcinol significantly reduced the levels of lysine, phenylalanine, histidine, leucine-isoleucine, methionine, valine, proline, threonine, and alanine in the thigh muscles. However, supplementation with pure 4-hexylresorcinol significantly increased the concentrations of P, Fe, Se, Zn, and B and decreased the concentrations of I, Ni, V, Al, and Pb in the pectoral muscles. Supplementation with the combination 4-hexylresorcinol + gamma-octalactone + 7-hydroxycoumarin resulted in the accumulation of Ca, Co, Fe, Mn, Se, Zn, and Li and a decrease in the concentrations of K, Mg, and V.

Conclusion

Supplementation with all the tested additives, except the combination 4-hexylresorcinol + 7-hydroxycoumarin, exerted a positive effect on the indicators of live weight gain and dietary nutrient digestibility in broiler chickens. Supplementation with the combinations 4-hexylresorcinol + gamma-octalactone and 4-hexylresorcinol + gamma-octalactone + 7-hydroxycoumarin increased the amount of fat in the pectoral muscles but decreased it in the thigh muscles. Supplementation with all the tested additives decreased the concentrations of I in the pectoral muscles and Zn in the thigh muscles in all the experimental groups compared with those in the control group.

Systematic profiling of the chicken gut microbiome reveals dietary supplementation with antibiotics alters expression of multiple microbial pathways with minimal impact on community structure

BACKGROUND

The emergence of antimicrobial resistance is a major threat to global health and has placed pressure on the livestock industry to eliminate the use of antibiotic growth promotants (AGPs) as feed additives. To mitigate their removal, efficacious alternatives are required. AGPs are thought to operate through modulating the gut microbiome to limit opportunities for colonization by pathogens, increase nutrient utilization, and reduce inflammation. However, little is known concerning the underlying mechanisms. Previous studies investigating the effects of AGPs on the poultry gut microbiome have largely focused on 16S rDNA surveys based on a single gastrointestinal (GI) site, diet, and/or timepoint, resulting in an inconsistent view of their impact on community composition.

METHODS

In this study, we perform a systematic investigation of both the composition and function of the chicken gut microbiome, in response to AGPs. Birds were raised under two different diets and AGP treatments, and 16S rDNA surveys applied to six GI sites sampled at three key timepoints of the poultry life cycle. Functional investigations were performed through metatranscriptomics analyses and metabolomics.

RESULTS

Our study reveals a more nuanced view of the impact of AGPs, dependent on age of bird, diet, and intestinal site sampled. Although AGPs have a limited impact on taxonomic abundances, they do appear to redefine influential taxa that may promote the exclusion of other taxa. Microbiome expression profiles further reveal a complex landscape in both the expression and taxonomic representation of multiple pathways including cell wall biogenesis, antimicrobial resistance, and several involved in energy, amino acid, and nucleotide metabolism. Many AGP-induced changes in metabolic enzyme expression likely serve to redirect metabolic flux with the potential to regulate bacterial growth or produce metabolites that impact the host.

CONCLUSIONS

As alternative feed additives are developed to mimic the action of AGPs, our study highlights the need to ensure such alternatives result in functional changes that are consistent with site-, age-, and diet-associated taxa. The genes and pathways identified in this study are therefore expected to drive future studies, applying tools such as community-based metabolic modeling, focusing on the mechanistic impact of different dietary regimes on the microbiome. Consequently, the data generated in this study will be crucial for the development of next-generation feed additives targeting gut health and poultry production. Video Abstract.

Effects of Dietary L-Theanine on Growth Performance, Antioxidation, Meat Quality, and Intestinal Microflora in White Feather Broilers With Acute Oxidative Stress

In order to reduce the negative effects caused by oxidative stress on broilers, it is particularly important to find ways to alleviate oxidative stress. As a natural plant extract, L-theanine has a variety of biological effects, such as improving antioxidant capacity, promoting growth, and enhancing immunity and antitumor. This trial evaluated the effects of dietary supplementation of L-theanine on growth performance, antioxidation, meat quality, and intestinal microflora in 817 White Feather Broilers. A total of 108 21-day-old 817 broilers with similar body weight (BW) were randomly divided into three groups with six replicates per group and six chickens within each replicate. The three groups were corn-soybean-based diet (NC group); basal diet plus drinking water with 30 mg hydrocortisone/kg (PC group); and basal diet supplemented with 400 mg L-theanine/kg plus drinking water with 30 mg hydrocortisone/kg (LT group). Compared with the NC group, from 21 to 24 days of age, the PC and LT groups had decreased BW, average daily gain (ADG), and average daily feed intake (ADFI), and increased feed to gain ratio (F/G; p < 0.05). At 24 days of age, the LT group had improved superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum as compared to the NC group (p < 0.05). The LT group broilers also had significantly higher concentrations of malondialdehyde (MDA) in serum and liver (p < 0.05). On the 42nd days, the PC group had lower PH_45min (p < 0.05) than the NC and LT groups and higher cooking loss and shear force (p < 0.05). Moreover, the villi height of the PC group was significantly lower in jejunum than the NC group (p < 0.05). The LT group had a higher ZO-1 content in duodenum than the NC and PC groups (p < 0.05). The activity of GSH-Px in the liver of the LT group was increased than in the PC group (p < 0.05). The relative abundance of Firmicutes in the LT group was significantly higher than in the NC and PC groups (p < 0.05). These results suggested that the effects of acute oxidative stress on growth performance and meat quality of broilers are continuous, and dietary supplementation of L-theanine could improve the growth performance and meat quality, enhance the intestinal mucosal barrier and antioxidant capacity, and improve the composition of the intestinal flora of broilers caused by acute oxidative stress.

L-Theanine: A Unique Functional Amino Acid in Tea (Camellia sinensis L.) With Multiple Health Benefits and Food Applications

Tea (Camellia sinensis L.) is a very popular health drink and has attracted increasing attention in recent years due to its various bioactive substances. Among them, L-theanine, a unique free amino acid, is one of the most important substances in tea and endows tea with a special flavor. Moreover, L-theanine is also a bioactive compound with plenty of health benefits, including antioxidant, anti-inflammatory, neuroprotective, anticancer, metabolic regulatory, cardiovascular protective, liver and kidney protective, immune regulatory, and anti-obesity effects. Due to the unique characteristics and beneficial functions, L-theanine has potential applications in the development of functional foods. This review summarized the influencing factors of L-theanine content in teas, the main health benefits and related molecular mechanisms of L-theanine, and its applications in food, understanding of which can provide updated information for the further research of L-theanine.

Effect of probiotic supplementation on the expression of tight junction proteins, innate immunity-associated genes, and microbiota composition of broilers subjected to cyclic heat stress

This study investigated the effects of probiotic on intestinal innate immunity-associated gene expression and cecal microbiota in heat-stressed broilers. A total of 180 21-day-old male broilers were randomly assigned to three treatment groups with four replicates per group. The thermoneutral group (TN) (23 ± 1°C) received a basal diet, and another two heat-stressed groups (28-35-28°C for 12 h daily) were fed the basal diet (HS) or the basal diet supplemented with probiotic at a dose of 1.5 × 10⁸  CFU/kg (HS_Pro) for 21 consecutive days. Compared with the TN group, the abundance of beneficial bacteria was decreased (p < 0.05) in the caecum of heat-stressed broilers. Heat stress downregulated (p < 0.05) the expression of Toll-like receptor (TLR)2 and upregulated (p < 0.05) the expressions of TLR5, TLR15, avian β-defensin (AvBD)4, AvBD8, and AvBD14 in the ileum as compared with the TN group. Dietary supplementation of probiotic upregulated (p < 0.05) the occludin expression in the ileum, improved the microbiota balance in the caecum, and decreased (p < 0.05) the gene expressions of TLR5 and TLR15 in the ileum of heat-stressed broilers. Collectively, dietary probiotic supplementation could promote intestinal barrier function via improving gut microbiota community and regulating innate immunity-associated gene expressions in heat-stressed broilers.

A novel Lactobacillus bulgaricus isolate can maintain the intestinal health, improve the growth performance and reduce the colonization of E. coli O157:H7 in broilers

1. This study aimed at the effects of a novel Lactobacillus bulgaricus (L. bulgaricus) strain and Enterohemorrhagic Escherichia coli (E. coli) O157: H7 on intestinal flora and growth performance of broilers, and the protective effect of L. bulgaricus on broilers in challenged experiment by E. coli O157: H7.2. In vitro bacteriostatic test showed that the cell-free supernatant (CFS) of L. bulgaricus isolate had obvious inhibitory effect on E. coli O157: H7.3. Eighty 1-day-old male broilers were randomly assigned into 4 treatment groups with 4 replicate per treatment. All group received basic diet in addition to the specific treatments: NC group, gavage with normal saline; In LBP group, gavage with L. bulgaricus isolate (1×10⁹ CFU/mL) during the whole process, and challenged with E. coli O157: H7 (3×10⁹ CFU/mL); EC group, gavage with E. coli O157: H7 (3×10⁹ CFU/mL); LB Group, gavage with L. bulgaricus isolate. At the age of 21 days, broilers were weighed and feed conversion ratio (FCR) was calculated. Cecum and cecal contents, ileum and feces samples were taken after slaughter.4. The challenge of E. coli O157: H7 resulted in an increase in TLR-4, NF-κB and IL-8 mRNA in cecal tissue, a decrease in Villus: crypt ratio in ileum, a decrease in overall diversity of intestinal microflora and a poor FCR.5. The L. bulgaricus isolate decreased the mRNA expression of TLR-4, NF-κB and IL-8 induced by E. coli O157: H7, reduced the content of E. coli O157: H7 in the cecum of broilers, increased the Villus: crypt ratio, increased the abundance of beneficial bacteria and overall diversity of intestinal microflora, made good FCR.6. The L. bulgaricus isolate can maintain the intestinal health, improve the growth performance of broilers and reduce the colonization of E. coli O157:H7 in the cecum.

Functional roles of taurine, L-theanine, L-citrulline, and betaine during heat stress in poultry

Heat stress (HS) is an important environmental stress factor affecting poultry production on a global scale. With the rise in ambient temperature and increasing effects of global warming, it becomes pertinent to understand the effects of HS on poultry production and the strategies that can be adopted to mitigate its detrimental impacts on the performance, health, welfare, immunity, and survival of birds. Amino acids (AAs) have been increasingly adopted as nutritional modifiers in animals to ameliorate the adverse effects of HS. They are essential for protein synthesis, growth, maintenance, reproduction, immunity, stress response, and whole-body homeostasis. However, HS tends to adversely affect the availability, transport, absorption, and utilization of these AAs. Studies have investigated the provision of these AAs to poultry during HS conditions, and variable findings have been reported. Taurine, L-theanine, and L-citrulline are non-essential amino acids that are increasingly gaining attention as nutritional supplements in HS animals. Similarly, betaine is an amino acid derivative that possesses favorable biological properties which contributes to its role as a functional additive during HS. Of particular note, taurine is negligible in plants, while betaine, L-theanine, and L-citrulline can be found in selected plants. These nutrients are barely found in feed ingredients, but their supply has been shown to elicit important physiological roles including anti-stress effects, anti-oxidative, anti-inflammatory, gut promoting, and immunomodulatory functions. The present review provides information on the use of these nutritionally and physiologically beneficial nutrients as functional additives to poultry diets during HS conditions. Presently, although several studies have reported on the positive effects of these additives in human and murine studies, however, there is limited information regarding their utilization during heat stress in poultry nutrition. Therefore, this review aims to expound on the functional properties of these nutrients, their potentials for HS alleviation, and to stimulate further researches on their biological roles in poultry nutrition.

Phytogenic Feed Additives in Poultry: Achievements, Prospective and Challenges

Simple Summary

Plant secondary metabolites and essential oils also known as phytogenics are biologically active compounds that have recently attracted increased interest as feed additives in poultry production, due to their ability to promote feed efficiency by enhancing the production of digestive secretions and nutrient absorption, reduce pathogenic load in the gut, exert antioxidant properties and decrease the microbial burden on the animal’s immune status. However, the mechanisms are far from being fully elucidated. Better understanding the interaction of phytogenics with gastrointestinal function and health as well as other feed ingredients/additives is crucial to design potentially cost-effective blends.

Abstract

Phytogenic feed additives have been largely tested in poultry production with the aim to identify their effects on the gastrointestinal function and health, and their implications on the birds’ systemic health and welfare, the production efficiency of flocks, food safety, and environmental impact. These feed additives originating from plants, and consisting of herbs, spices, fruit, and other plant parts, include many different bioactive ingredients. Reviewing published documents about the supplementation of phytogenic feed additives reveals contradictory results regarding their effectiveness in poultry production. This indicates that more effort is still needed to determine the appropriate inclusion levels and fully elucidate their mode of actions. In this frame, this review aimed to sum up the current trends in the use of phytogenic feed additives in poultry with a special focus on their interaction with gut ecosystem, gut function, in vivo oxidative status and immune system as well as other feed additives, especially organic acids.

Protective Effect of l-Theanine against DSS-Induced Colitis by Regulating the Lipid Metabolism and Reducing Inflammation via the NF-κB Signaling Pathway

The present study revealed the phylactic effects of l-theanine on a DSS-induced colitis mice model. The results showed that 3% DSS treatment significantly induced intestinal damage as reflected by DAI, histopathological feature, and colon length, while l-theanine pretreatment markedly prevented these trends to exert protective effects. Meanwhile, l-theanine pretreatment decreased the levels of TNF-α, IL-1β, IL-6, iNOS, and COX2 on DSS-induced colitis. Notably, DSS inhibited the proliferation and promoted the apoptosis of intestinal epithelial cells, thereby damaging the integrity of the intestinal epithelial barrier, whereas l-theanine also played a protective role by attenuating these deteriorated effects. It was also observed that l-theanine treatment downregulated the levels of p-p65, p65, p-p53, p53, and p-AKT protein expression in acute DSS-induced colitis, which showed the protective function of l-theanine, mainly via the NF-κB signaling pathway. Furthermore, the results of lipid analysis and transcriptome analysis show that l-theanine reversed transcriptional profiles and lipid profiles of colitis models, mainly via the inflammatory reactivity-related pathway. Interestingly, the correlation analysis between transcriptional profiles and lipid profiles showed that inflammatory response-related genes were almost significantly correlated with differential lipid metabolites. In summary, l-theanine plays a protective role in DSS-induced colitis via downregulating the NF-κB signaling pathway and regulating lipid metabolism disorders.

L-Theanine affects intestinal mucosal immunity by regulating short-chain fatty acid metabolism under dietary fiber feeding

To investigate the effects of l-Theanine (LTA) on intestinal mucosal immunity and the regulation of short-chain fatty acid (SCFA) metabolism under dietary fiber feeding, a 28-day feeding experiment was performed in Sprague-Dawley rats. The results show that LTA increased the proportion of Prevotella, Lachnospira, and Ruminococcus while increasing the total SCFA, acetic acid, propionic acid, and butyric acid contents in the feces. LTA also increased IgA, IgE, and IgG levels in the ileum, and increased villi height and crypt depth. Moreover, LTA upregulated the mRNA and protein expression of acetyl-CoA carboxylase 1, sterol element-binding protein 1c, fatty acid synthase, and 3-hydroxy-3-methylglutaryl coenzyme A reductase in the liver, while downregulating the expression of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase 1 in the colon. Our study suggests that LTA can affect intestinal mucosal immunity by regulating SCFA metabolism under dietary fiber feeding.

The protective effects of yellow tea extract against loperamide-induced constipation in mice

Yellow tea, a rare type tea from China, has a rich breadth of functional ingredients and benefits the gastrointestinal tract. However, it is not clear whether the yellow tea extract can alleviate constipation. Therefore, we used loperamide-induced constipation in mice to evaluate the effects of yellow tea extract. Fifty Kunming mice were randomly divided into five groups: normal, model, low-dose yellow tea extract, low-dose yellow tea extract prevention group, and high-dose yellow tea extract prevention group. Mice were administered yellow tea extract for 5 weeks followed by loperamide-induced constipation for the final 2 weeks. The results showed that yellow tea extract alleviated constipation symptoms by improving the fecal water content, defecation weight, and gastrointestinal transit rate. Yellow tea extract intervention also protected colon tissue, regulated serum neurotransmitters, and decreased the vasoactive intestinal peptide level. Furthermore, qRT-PCR indicated that yellow tea extract regulated genes associated with the constipation state, raised 5-HT3 and 5-HT4 and reduced AQP3 and AQP4 mRNA expression. Moreover, we found that yellow tea extract changed the gut microbiota composition. Community diversity and richness were increased and principal co-ordinate analysis demonstrated that the yellow tea extract prophylaxis groups differed from the model group. Difference analysis indicated that yellow tea extract increased Roseburia, Lachnospiraceae_UCG-006, and Bifidobacterium and decreased norank_f_Clostridiales_vadinBB60_group, unclassified_o_Bacteroidales, and Bacteroides, which are correlated with constipation. Based on these results, we believe that regular yellow tea consumption can effectively alleviate constipation.

The biological effects of microencapsulated organic acids and botanicals induces tissue-specific and dose-dependent changes to the Gallus gallus microbiota

Background

Microencapsulated organic acids and botanicals have the potential to develop into important tools for the poultry industry. A blend of organic acids and botanicals (AviPlus®P) has previously shown to reduce Salmonella and Campylobacter in chickens; however, changes to the microbiota of the jejunum and ileum have not been evaluated. Microbiota diversity is linked to, but not correlated with, the efficacy of natural products; therefore, understanding the effects on the microbiota is necessary for evaluating their potential as an antibiotic alternative.

Results

Ileal and jejunal segments from control and supplement-fed chickens (300 and 500 g/metric ton [MT]) were subjected to alpha diversity analysis including Shannon’s diversity and Pielou’s Evenness. In both analytics, the diversity in the ileum was significantly decreased compared to the jejunum irrespective of treatment. Similarly, beta diversity metrics including Bray-Curtis dissimilarity index and Weighted Unifrac Distance Matrix, were significant (Q < 0.05) for both tissue and treatments comparisons. Alpha and beta diversity analytics indicated compartmentalization effects between the ileum and jejunum. Additionally, analysis of communities in the microbiota (ANCOM) analysis showed Lactobacilliaceae predominated the total operational taxonomic units (OTU), with a stepwise increase from 53% in the no treatment control (NTC) to 56% in the 300 g/MT and 67% in the 500 g/MT group. Staphylococcaceae were 2% in NTC and 2 and 0% in 300 and 500 g/MT groups. Enterobacteriaceae decreased in the 500 g/MT (31%) and increased in the 300 g/MT (37%) compared to the NTC (35%). Aerococcaceae was 0% for both doses and 7% in NTC. Ruminococcaceae were 0% in NTC and 2 and 1% in the 300 and 500 g/MT. These changes in the microbial consortia were statistically (Q < 0.05) associated with treatment groups in the jejunum that were not observed in the ileum. Least discriminant analysis effect size (LEfSE) indicated different changes directly corresponding to treatment. Enterobacteriaceae demonstrated a stepwise decrease (from NTC onward) while Clostridiaceae, were significantly increased in the 500 g/MT compared to NTC and 300 g/MT (P < 0.05).

Conclusion

The bioactive site for the microencapsulated blend of organic acids and botanicals was the jejunum, and dietary inclusion enhanced the GIT microbiota and may be a viable antibiotic alternative for the poultry industry.

Prospects of yeast based feed additives in poultry nutrition: Potential effects and applications

Yeast and its derivatives are extensively utilized as feed additives in poultry industry owing to their desirable health and growth promoting effects. Exhaustive number of studies had reported positive effects of yeast based additives on growth, meat quality, immunity, antioxidant status, and gastrointestinal functions in poultry birds. Owing to their prebiotic/probiotic properties, they also play significant role in gut development and modulation of gut microbiome by favouring beneficial microbes while reducing colonization of pathogenic microbes by competitive exclusion. They also possess effective potential for binding of dietary toxins in addition to improving digestion and utilization of nutrients. Moreover, yeast based additives have exhibited desirable effects on humoral immunity by increasing serum immunoglobulin (Ig) A levels. These additives have been also used as immune adjuvants to boost innate immune response under any pathogenic challenges in birds. Due to their diverse biological activities, yeast products are potentially capable for immune hemostasis by mediating balance between pro- and anti-inflammatory activities. These unique properties of yeast based products make them promising feed additive to promote health and productivity leading to efficient poultry production. Yeast can be supplemented in poultry diets @ 5.0–10.0 g/kg of feed. Numerous studies had reported significant improvement in body weight gain (3 to 8%) and FCR (1.6 to 12%) in broilers in response to supplementation of yeast based additives. Moreover, yeast supplementation also improved hemoglobin (Hb g/dl) levels up to 2.59 to 6.62%, total protein (>0.69%) while reducing serum cholesterol (mg/dl) up to 3.68 to 13.38%. Despite the potential properties and beneficial effects, use of yeast and its derivatives as feed additives in poultry industry is not matching its inherent potential due to many reasons. This review aims to highlight the importance and potential role of yeast and its products as natural growth promoter to replace in feed antibiotics to address the issues of antibiotic residues and microbial resistance. This article provides insights on functional role of yeast based additives in poultry diets and their importance as commercially viable alternatives of antibiotic growth promoters in poultry feed industry.

Effects of phytobiotic feed additives on growth traits, blood biochemistry, and meat characteristics of broiler chickens exposed to Salmonella typhimurium

Because of concerns over the use of antibiotics in poultry feed, this study was designed to determine the effectiveness of phytobiotic supplementation as an alternative to antibiotic use based on growth performance and meat characteristics of broilers exposed to Salmonella typhimurium. The effects of an antibiotic and 3 phytobiotic feed additives (PFA), Mix-Oil Mint (MO_mint), Mix-Oil Liquid (MO_liq), and Sangrovit Extra (Sang_ext), were compared. At day of age, 280 Ross chicks were randomly allocated into 6 treatments. At 15 d, all chicks except negative control were exposed to S. typhimurium. The offered 6 diets were as follows: T1, negative control; T2, infected with S. typhimurium; T3, infected + avilamycin (0.1 g/kg); T4, infected + MO_mint (0.2 g/kg); T5, infected + plant extract in liquid form MO_liq (0.25 mL/L); and T6, infected + Sang_ext (0.15 g/kg). During the cumulative starter period, PFA improved performance over that of the control, and the food conversion ratio (FCR) was lower for T3 and T5 compared with T1 (P < 0.05). During the cumulative finisher period (15–35 d), a lower body weight gain (P < 0.01) was observed in T2. T1 had the best FCR and production efficiency factor, but they were not significantly different from those of T3, T4, and T6 (P < 0.001). At 35 d, T1 and T4 had a higher breast percentage as compared with those of T2 (P < 0.05). Blood glucose decreased significantly (P > 0.05) in T2 and T5 compared with that in T1 and T4. Alanine transaminase concentration decreased significantly (P < 0.01) in T4 and T5 compared with that in T1, T2, and T3. Treatments had significant effects on breast temperature and pH (P < 0.001). A significant decrease in the myofibril fragmentation index occurred in T1 and T6. Hardness and chewiness were influenced by treatments (P < 0.05). In conclusion, dietary supplementation with PFA could effectively compare with that of antibiotic avilamycin in the maintenance of growth performance and improvement in meat characteristics of broilers challenged with S. typhimurium.

L-theanine: an astounding sui generis amino acid in poultry nutrition

L-theanine (γ-Glutamylethylamide) is a nonprotein water soluble amino acid (AA) mostly found in leaves of Camellia sinensis (green tea). This is a key component of green tea and is considered as the most abundant form of total AAs in green tea (i.e., about 50%). L-theanine is an exclusive taste ingredient of tea producing an attractive flavor and aroma in tea. It has biological effects such as antioxidant, growth promoter, immune booster, anti-stresser, hepatoprotective, antitumor, antiaging, antimicrobial, anti-inflammatory, and antianxiety activities that are worth noticing. It could reduce the oxidative impairment by reducing the synthesis of reactive oxygen species, oxidative parameters, and lipid damage as well as increasing the activity of antioxidant enzymes. The oral ingestion of L-theanine enhanced γδ T-cell proliferation. Therefore, it is being considered an essential compound of green tea that has the ability to improve immune function. The L-theanine can be used as a potential treatment for hepatic injury and immune-related liver diseases via the downregulation of the inflammatory response through the initiation of nitric oxide synthesis and glutathione production which are likely to be critical for the control of hepatic diseases as well as for the improvement of immune function. In addition, it could be used as a best natural feed additive with a potent antistressor by decreasing the levels of corticosterone, dopamine, and noradrenaline. After systematically reviewing the literature, it is noticed that most studies were carried out on mice, pig, human, and butterfly; while dietary supplementation studies of L-theanine in animal and poultry especially among broilers are very limited because of less awareness of this AA. So, the aim of this review is to encourage the veterinarian and poultry researchers to conduct more research at the molecular level about this AA to expose its more beneficial effects and its mechanism of absorption for potential use of this unique green tea AA in poultry nutrition.

Ameliorative effects of L-theanine on dextran sulfate sodium induced colitis in C57BL/6J mice are associated with the inhibition of inflammatory responses and attenuation of intestinal barrier disruption

This study investigated the effects of L-theanine supplementation on the colonic mucosa injury in C57BL/6J male mice treated with dextran sulfate sodium (DSS)-induced colitis. Treatment with L-theanine significantly decreased the disease activity index and ameliorated the inflammation-associated pathological damage in colon length, as well as the histopathological features of DSS-induced colitis. L-Theanine administration also inhibited DSS-induced changes in the colonic tissue that included myeloperoxidase by 4.5-fold and malondialdehyde by 2.3-fold in comparison to the DSS group. In addition, GSH was increased by 85% and lipopolysaccharides level was decreased by 55% in comparison to the DSS group. Proinflammatory cytokines expression, including interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, at the both protein and mRNA levels were also decreased significantly. Notably, the increase in serum content of lipopolysaccharides and colonic expressions of inducible nitric oxide synthase, cyclooxygenase-2, toll like receptor (TLR)-2, TLR-4, TLR-6, and TLR-9 induced by DSS were also significantly inhibited by L-theanine administration. In addition, L-theanine also attenuated the reduction of serum contents of diamine oxidase and the production of short-chain fatty acids in the colonic tissue, and gene expression of mucosal barrier zonula occludens-1 and claudin-1 in DSS-induced colitis. Furthermore, 16S rRNA phylogenetic sequencing revealed a shift in microbial community composition induced by DSS, but no significant difference was observed following L-theanine supplementation. Overall, our findings demonstrated that L-theanine inhibits intestinal inflammation and protects against intestinal barrier disruption in mice with DSS-induced colitis. Further clinical trials should be considered to assess the effects of L-theanine supplementation on oxidative and inflammatory responses in humans.

Green Tea and Pomegranate Extract Administered During Critical Moments of the Production Cycle Improves Blood Antiradical Activity and Alters Cecal Microbial Ecology of Broiler Chickens

Simple Summary

Since the European Union’s (EU) antibiotic ban in 2006, interest in natural feed additives has largely increased. Natural feed additives are used to prevent diseases and promote growth in chickens, supporting animal health and modulating the development of the gut microflora during stressful situations. In the present study, a bioactive compound from plants belonging to the class of phytobiotics was assessed for its effects on production performance, antiradical activity and gut microflora in broiler chickens. The obtained results show how the tested compound is able to exert beneficial effects on the antiradical activity and gut microbial ecology of birds, even though the chickens’ performance was unaffected.

Abstract

Phytobiotics are usually tested in feed and throughout the production cycle. However, it could be beneficial to evaluate their effects when administered only during critical moments, such as changes in feeding phases. The aim of the trial was to investigate the effect of a commercial plant extract (PE; IQV-10-P01, InQpharm Animal Health, Kuala Lumpur, Malaysia) on growth performance, blood antiradical activity and cecal microbiome when administered in drinking water to broiler chickens during the post-hatching phase and at each change of diet. In the experiment, 480 1-day-old male broiler chicks were assigned to two groups in a 50-day trial. Broilers received drinking water (C) or drinking water plus PE (T) at a rate of 2 mL/L on days 0 to 4, 10–11 and 20–21. PE did not affect performance and water intake, while total antiradical activity was improved (p < 0.05). A greater abundance of lactic acid bacteria (false discovery rate (FDR) < 0.05) was found in the T group and the result was confirmed at a lower taxonomic level with higher Lactobacillaceae abundance (FDR < 0.05). Our findings suggest that PE administration during critical moments of the production cycle of broiler chickens may exert beneficial effects at a systemic level and on gut microbial ecology.

Cottonseed meal fermented by Candida tropical reduces the fat deposition in white-feather broilers through cecum bacteria-host metabolic cross-talk

In the present study, effects of cottonseed meal fermented by Candida tropicalis (FCSM) on fat deposition, cecum microbiota, and metabolites and their interactions were studied in broilers. A total of 180 1-day-old broilers were randomly assigned into two groups with six replicates of 15 birds in each. The birds were offered two diets consisted one control, i.e., supplemented with 0% FCSM (CON) and an experimental, with 6% FCSM (FCSM). Illumina MiSeq sequencing and liquid chromatography-mass spectrometry were used to investigate the profile changes of the cecum microbes and metabolites and the interactions among fat deposition, microbes, and metabolites. Results showed that at the age of 21 days, both the abdominal fat and subcutaneous fat thickness of the experimental birds decreased significantly (P < 0.05) in response to the dietary FCSM supplementation. The predominant microbial flora in cecum consisted Bacteroidetes (53.55%), Firmicutes (33.75%), and Proteobacteria (8.61%). FCSM diet increased the relative abundance of Bacteroides but decreased obese microbial including Faecalibacterium, Lachnospiraceae, Ruminococcaceae, and Anaerofilum. Cecum metabolomics analysis revealed that lipids, organic acids, vitamins, and peptides were significantly altered by adding FCSM in diet. Correlation analysis showed that abdominal fat and subcutaneous fat thickness related negatively with Bacteroides while the same related positively with Faecalibacterium, Lachnospiraceae, and Ruminococcaceae. Moreover, abdominal fat and subcutaneous fat thickness were related negatively with nicotinic acid, sebacic acid, thymidine, and succinic acid. These findings indicated that FCSM reduced the fat deposition by regulating cecum microbiota and metabolites in broilers. The results are contributory to the development of probiotics and the improvement in the production of broilers.

Effect of l-theanine on growth performance, intestinal development and health, and peptide and amino acid transporters expression of broilers

BACKGROUND

l-Theanine has multiple beneficial biological activities. However, there is little information about the use of l-theanine in broiler production. Therefore, this study investigated the effect of l-theanine on growth performance, intestinal development and health, and the mRNA levels of intestinal peptide and amino acid (AA) transporters of broilers.

RESULTS

Body weight and average daily gain were increased by l-theanine, whereas feed to gain ratio was decreased (quadratic, P < 0.05). Notably, the relative weight of duodenum, jejunum and ileum, villus height, villus height to crypt depth ratio, the jejunal activities of glutathione peroxidase, total antioxidant capacity, catalase and total superoxide dismutase were increased linearly and/or quadratically by l-theanine (P < 0.05), whereas crypt depth, serum d-lactic acid, and jejunal protein carbonyls and malondialdehyde content were decreased linearly and/or quadratically (P < 0.05). Moreover, l-theanine enhanced the jejunal mRNA levels of occludin, claudin-1, E-cadherin, zona occludens-1, di- and tripeptide transporter, excitatory AA transporter 3, Na⁺ -independent cationic AA transporter 1, Na⁺ -independent cationic and zwitterionic AA transporter, Na⁺ - and Cl^- -dependent neutral and cationic AA transporter, Na⁺ -independent cationic and Na⁺ -dependent neutral AA transporter (y+LAT) 1, y+LAT2, Na⁺ -independent branched-chain and aromatic AA transporter, and heavy chain corresponding to the b°^,+ transport system (linear and/or quadratic, P < 0.05).

CONCLUSIONS

l-Theanine beneficially affected the growth performance of broilers by improving intestinal development and health, and the intestinal mRNA levels of AA and peptide transporters. Therefore, l-theanine has the potential to be a promising feed additive for broilers. © 2020 Society of Chemical Industry.

Nutritional applications and beneficial health applications of green tea and l-theanine in some animal species: A review

Green tea (Camellia sinensis) is a popular herbal plant with abundant health benefits, and thus, it has been used as a potent antioxidant for a long time. Based on the available literature, the diversity and the availability of multifunctional compounds in green tea offer its noteworthy potential against many diseases such as liver and heart diseases, inflammatory conditions and different metabolic syndromes. Owing to its bioactive constituents including caffeine, amino acids, l-theanine, polyphenols/flavonoids and carbohydrates among other potent molecules, green tea has many pharmacological and physiological effects. The effects of green tea include anti-oxidative, anti-inflammatory, anti-arthritic, anti-stress, hypolipidaemic, hypocholesterolaemic, skin/collagen protective, hepatoprotective, anti-diabetic, anti-microbial, anti-infective, anti-parasitic, anti-cancerous, inhibition of tumorigenesis and angiogenesis, anti-mutagenic, and memory and bone health-improving activities. Apart from its utilization in humans, green tea has also played a significant role in livestock production such as in dairy, piggery, goatry and poultry industries. Supplementation of animal feeds with green tea and its products is in line with the modern concepts of organic livestock production. Hence, incorporating green tea or green tea by-products into the diet of poultry and other livestock can enhance the value of the products obtained from these animals. Herein, an effort is made to extend the knowledge on the importance and useful applications of green tea and its important constituents in animal production including poultry. This review will be a guideline for researchers and entrepreneurs who want to explore the utilization of feeds supplemented with green tea and green tea by-products for the enhancement of livestock production.

L-theanine attenuates transport stress-induced impairment of meat quality of broilers through improving muscle antioxidant status

This study was to investigate the effect of dietary L-theanine (THE) supplementation (0, 600 mg/kg) on growth performance, carcass traits, immune organ indexes, meat quality, and muscle antioxidant status of transported broilers. A total of 180 one-day-old male Ross 308 broilers were randomly allotted to 2 treatment groups including a THE-free group with 12 replicates of 10 birds each and a THE group with 6 replicates of 10 birds each. On the morning of day 42, after a 9-h fast, the birds of THE-free group were divided into 2 equal groups, and then all birds in the 3 groups were placed into 18 crates and were transported according to the following protocols: 0-h transport of birds in the THE-free group (control group), 3-h transport of birds in the THE-free group (T group), and 3-h transport of birds in the THE group (T + THE group). Results showed that dietary THE supplementation improved feed conversion ratio and birds' final body weight (P < 0.05), while transport and dietary THE supplementation did not affect carcass traits of broilers (P > 0.05). Transport increased bird live weight loss, drip loss, L*24 h, muscle malondialdehyde (MDA), protein carbonyl (PC) and lactate contents, while it decreased thymus, spleen, and bursa of Fabricius indexes, pH24h, a*, and muscle total antioxidant capacity (T-AOC), catalase (CAT), and glutathione peroxidase (GSH-PX) activities and glycogen content (P < 0.05). Nevertheless, compared with birds in the T group, birds in the T + THE group exhibited increased thymus, spleen, and bursa of Fabricius indexes, pH24h, a*24 h, and muscle T-AOC, CAT, and GSH-PX activities and glycogen content, and decreased drip loss, L*24 h, and muscle MDA, PC, and lactate contents (P < 0.05). This study provided the first evidence that dietary THE supplementation prevented transport-stress-impaired immune organ indexes and meat quality of broilers, and the reason for maintenance of meat quality by supplementation of THE may be partly ascribed to the changed muscle glycolysis metabolism and antioxidant status.