Effects of encapsulated cinnamaldehyde on growth performance, intestinal digestive and absorptive functions, meat quality and gut microbiota in broiler chickens

Dietary essential oil components: A systematic review of preclinical studies on the management of gastrointestinal diseases

BACKGROUND

The gut is responsible for the digestion and absorption of nutrients, immune regulation, and barrier function. However, factors like poor diet, stress, and infection, can disrupt the balance of the gut microbiota and lead to intestinal inflammation and dysfunction.

PURPOSE

This systematic review aims to evaluate the effects of dietary plants-derived essential oil components on gut health and intestinal functions in animal models.

METHODS

The literature was gathered from the Scopus, Web of Science, PubMed, and Embase databases by using related search terms, such as "dietary plants", "dietary sources", "essential oils", "gut health", "intestine", "anti-inflammatory", "antioxidant", and "gut microbiota".

RESULTS

The results indicate that plant-derived dietary essential oil components, such as butyrolactone-I, carvacrol, cinnamaldehyde, citral, D-limonene, eugenol, farnesol, geraniol, indole, nerolidol, oleic acid, thymol, trans-anethole, vanillin, α-bisabolol, α-linolenic acid, α-pinene, α-terpineol, β-carotene, β-caryophyllene, and β-myrcene have been found to regulate gut health by influencing vital signalling pathways associated with inflammation. Dietary essential oil components modulate the expression of tumor necrosis factor alpha, interleukin 1 beta (IL-1β), interleukin (IL)-6, IL-10, inducible nitric oxide synthase, cyclooxygenase-2, toll-like receptor-4, matrix metalloproteinase, and interferon gamma in mitigating gut inflammation. The primary signalling molecules controlled by these molecules were AMP-activated protein kinase (AMPK), protein kinase B, extracellular signal-regulated kinase, c-Jun N-terminal kinase, mitogen-activated protein kinase, myeloid differentiation primary response 88, nuclear factor erythroid-2-related factor-2, and phosphoinositide 3-kinase (PI3K). Moreover, these phytochemicals have been shown to improve glucose homeostasis by regulating glucose transporter 4, glucagon-like peptide-1, peroxisome proliferator-activated receptor gamma, nuclear factor kappa B, AMPK, PI3K, and uncoupling protein-1. They can also reduce thiobarbituric acid reactive substance, malondialdehyde, and oxidative stress and enhance superoxide dismutase, catalase, and glutathione peroxidase levels.

CONCLUSION

In conclusion, dietary plants-derived essential oil components have the potential to mitigate inflammation and oxidative stress in the gut. However, additional clinical investigations are necessary to confirm their complete potential in improving human gut health functions.

Productive, internal organ and intestinal histomorphological characteristics of broiler chickens in response to dietary rapeseed meal: A meta-analysis

The use of rapeseed as a source of protein in broiler chicken diets has been highlighted. However, there are inconsistent findings on the performance data of broiler chickens fed rapeseed meal (RSM). Therefore, this meta-analysis aimed to resolve the inconsistent findings on the effect of RSM on growth performance, carcass characteristics, internal organs, and intestinal histomorphology of broiler chickens, identify knowledge gaps and create new insights using published data. Fourteen studies on the topic were identified via a systematic search performed on bibliographic databases, and the data generated was analysed using OpenMEE software. A random-effects model was used, and effect sizes were presented as standardised mean difference (SMD) at a 95% confidence interval (CI). Sources of heterogeneity were evaluated using broiler strains, inclusion levels, processing methods, rearing phases and sex as moderators. In comparison with the controls, the results showed that RSM decreased feed intake (SMD = -0.29; 95% Cl: -0.41, -0.18; p < 0.001), average daily gain (SMD = -0.48; 95% Cl: -0.63, -0.32; p < 0.001), and liver weight (SMD = 1.24; 95% Cl: 0.78, 1.71; p < 0.001), but had no effect on feed conversion ratio (SMD = 0.10; 95% Cl: -0.05, 0.23; p = 0.19). Likewise, broiler chickens fed RSM had significantly reduced carcass yield, weights of thigh, abdominal fat and heart when compared with the control. Results indicate that duodenum villus height (DVH) and jejunum villus height (JVH)/crypt depth (CD) ratios were improved in broiler chickens fed RSM. Meta-regression revealed that the analysed moderators are significant predictors of feed intake, average daily gain and feed conversion ratio in broiler chickens. In conclusion, dietary RSM negatively influenced growth performance, liver weight and carcass characteristics in broiler chickens, but improved aspects of intestinal histomorphology traits. Therefore, innovative research on processing methods that will improve the feeding value of rapeseed meal in broiler chickens is recommended.

Productive Performance and Carcass Characteristics of Broiler Chickens Fed on Diets with Different Protein, Energy Levels, and Essential Oils During the Warm Season in Dry Tropics

This study evaluated the productive performance and carcass traits of broiler chickens during the warm season in dry tropical conditions. Two hundred, 1-day-old chicks were used. Birds were fed on reduced (RED) and standard (STD) diets, and two essential oils (EOs) levels, 0 and 200 ppm. The RED diets were formulated with 10% less energy and 10% less protein than STD diets. In the starter phase, weight gain was greater (p < 0.01) in birds fed STD than birds fed RED. In the starter phase, productive variables were not affected (p ≥ 0.14) by EOs. In the finisher phase, greater feed intake (p = 0.02) and higher weight gain (p = 0.04) were observed in chickens on STD. Feed conversion ratio was similar (p = 0.97) for STD and RED. Throughout this study (1-42 d), greater feed intake (p = 0.02) and higher weight gain (p < 0.01) were found in chickens on STD. Feed conversion ratio was similar (p = 0.51) for STD and RED. Broiler chickens on EO-supplemented diets had better feed conversion (p ≥ 0.08). Hot carcass weight was greater (p < 0.01) in birds on STD. Greater yields of leg-thigh (p = 0.01), back (p = 0.01), and wings (p < 0.01) were observed in RED. Carcass yields, breast yield, pH, and meat temperature were not influenced (p ≥ 0.14) by nutrient concentrations in the diet. Carcass evaluations were not affected (p ≥ 0.11) by EOs. Body temperature was lower (p = 0.03) in birds receiving RED, however EOs had no effect (p ≥ 0.22) on body temperature. For the length of the study, at 20:00 h, broiler chickens fed on RED diets showed lower (p = 0.04) body temperatures. In conclusion, broiler chickens were under heat stress during the study, and body temperatures were reduced in chickens fed on RED diets or with EOs. Diet modification or EO-supplementation may improve feed conversion, though RED diets may have a negative effect on weight gain or carcass values.

The Optimal Dietary Sodium or Chloride Level of Broilers Fed a Corn-Soybean Meal Diet from 22 to 42 Days of Age

The objective of this study was to assess the ideal dietary Na or Cl level for chickens from 22 to 42 d of age, utilizing a corn-soybean meal diet that maintains a 1:1 ratio of Na to Cl. At 22 d of age, a total of 288 male broilers of Arbor Acres were selected and randomly divided into one of six treatments. Each treatment contained eight replicates, with six chicks in each replicate. The control chicks were given a basic diet including 0.02% Na and 0.07% Cl without added Na or Cl, while the birds in other treatments were given diets containing different Na or Cl levels (0.13%, 0.19%, 0.25%, 0.31%, and 0.37%). With increasing dietary Na or Cl levels, linear (p < 0.0001) and quadratic (p < 0.0001) increases occurred in ADG, ADFI, and average daily water consumption, while F/G exhibited a linear (p < 0.0001) and quadratic (p < 0.0001) decrease from 22 to 42 d of age in broilers. Linear (p < 0.02) and quadratic increases (p < 0.03) were found in the heart indicator, serum Cl- concentrations, and blood Na+ and Cl- concentrations, whereas the kidney indicator, blood K+ concentrations, and serum K+, UA, and glucose (GLU) concentrations showed a linear (p < 0.04) and quadratic (p < 0.004) decrease with an increase in dietary Na or Cl levels. The excreta water content, liver indicator, and jejunal crypt depth also showed a linear increase (p < 0.02). The ideal levels of dietary Na or Cl were estimated to be 0.07% to 0.12%, based on the most suitable broken-line and asymptotic models (p ≤ 0.0002) using those sensitive indicators mentioned above. It was suggested that the suitable dietary Na or Cl level of 0.12% would adequately fulfill the Na or Cl metabolic demands of chickens from 22 to 42 d of age.

Investigation of the impact of diverse climate conditions on the cultivation suitability of Cinnamomum cassia using the MaxEnt model, HPLC and chemometric methods in China

Cinnamomum cassia Presl. is a subtropical plant that is used for food and medicine. Climate change has changed the suitable habitats of medicinal plants, which might have repercussions for the efficacy of herbal remedies. In this study, the potential distribution in each period of Cinnamomum cassia was predicted and the quality in different suitable habitats was evaluated. According to the results, (1) precipitation, temperature, and soil are the primary environmental variables influencing C. cassia distribution. (2) The high-suitable habitats of current climate scenarios were predominantly located in the southern regions (Guangdong and Guangxi etc.) of China, with an area of 706,129.08 km2. Under future climate scenarios, suitable habitats will increasingly move northward, with a greater concentration south of the Yangtze River, particularly in the 2090s SSP585 scenario, the total area of newly extended suitable habitat reaches 312,963.53 km2. (3) HPLC and FTIR, combined with chemometrics, can be effective methods for identifying different suitable habitats of C. cassia. The content of trans-cinnamaldehyde (0.85%) is significantly higher in the high suitability habitat compared to the medium-low suitability habitat (0.30%). Our findings can offer valuable guidance for the identification of suitable C. cassia cultivation areas in China, as well as for the evaluation of C. cassia resource quality and the rational use of resources in different suitable habitats.

Walnut meal improves meat quality by modulating intestinal microbes in white feather broilers

Improving the number of amino acids and unsaturated fatty acids in the diet is a good way to raise the quality of the meat. Currently, most research on the quality of broiler meat focuses on genetic traits; nevertheless, it is unclear how meat quality is regulated. This experiment was conducted to investigate the effects of different supplemental levels of walnut meal (WM) on growth performance, amino acid and fatty acid composition, microbial composition, and meat quality of white feather broilers. 1 week old white feather broilers (n = 120; Body weight 83.76 ± 2.32 g), were randomly divided into 3 treatments and 4 replicates. Walnut meal of basic diet (CK), 5 %(WM-L) and 10 %(WM-H) were added to the diets of white feather broilers, respectively. The results showed that walnut meal could increase L* 24 h (24 h brightness) of breast muscle of white feathered broilers (p < 0.05). The amount of essential amino acids (e.g., isoleucine, methionine, leucine, tryptophan, and phenylalanine), umami amino taste acids (glutamic acid), and PUFA/SFA (polyunsaturated fatty acid) (n-3PUFA and n-6 PUFA) in breast muscle increased as the dose was increased. Furthermore, walnut meal regulated amino acid flavour metabolism by increasing the relative abundance of Bacteroides, bifidobacterium, and enterococcus faecalis, according to 16S rRNA sequencing and functional prediction analysis. The correlation showed that amino acid and fatty acid composition was one of the key factors affecting pH value, meat color and tenderness of chicken. In conclusion, dietary addition of walnut meal can increase the content of essential amino acids and unsaturated fatty acids and the relative abundance of beneficial bacteria of broilers, which is of great significance for improving meat quality of white feather broilers.

The Combined Use of Cinnamaldehyde and Vitamin C Is Beneficial for Better Carcass Character and Intestinal Health of Broilers

The use of cinnamaldehyde and Vitamin C can improve immunity and intestinal health. A two-way factorial design was employed to investigate the main and interactive effects of cinnamaldehyde and vitamin C on the growth, carcass, and intestinal health of broiler chickens. A total of 288 one-day-old female Arbor Acres broiler chicks were randomly distributed among four treatment groups, consisting of six replicate cages with 12 birds each. Four treatments were basal diet or control (CON), supplemental cinnamaldehyde (CA) 300 g/ton (g/t), vitamin C (VC) 300 g/t, and cinnamaldehyde 300 g/t, and vitamin C 300 g/t (CA + VC), respectively. The results showed that supplemental CA did not affect the growth performance or slaughter performance of broilers at 21 days (d), 42 days (d), and 1-42 days (d); however, it could improve intestinal barrier function at 42 d of age and reduce the mRNA expression of inflammatory factors in the intestine at 21 d and 42 d of age. Supplemental VC showed a trend towards increasing body weight gain (BWG) at 21 d (p = 0.094), increased breast muscle rate (at 21-d 5.33%, p < 0.05 and at 42-d 7.09%, p = 0.097), and decreased the abdominal fat (23.43%, p < 0.05) and drip loss (20.68%, p < 0.05) at 42-d. Moreover, VC improves intestinal morphology and intestinal barrier function and maintains a balanced immune response. The blend of CA and VC significantly upregulated the mRNA expression of myeloid differentiation factor 88 (MyD-88) in the intestine at 21 d of age, the mRNA expression of catalase (CAT), Occludin, Claudin-1, Mucin-2, nuclear factor-kappa B (NF-κB) and toll-like receptor 4 (TLR-4) in the intestine at 42 d of age (p < 0.01), and downregulated the mRNA expression of interleukin 10 (IL-10), interleukin 6 (IL-6), tumor necrosis factor-alpha (TNF-α) in the intestine at 21-d and 42-d of age, and interleukin-1 beta (IL-1β) mRNA in intestine at 42 d of age (p < 0.01). This study suggested that the combination of CA and VC had the potential to regulate intestinal health and result in better carcass character of broilers.

Validating the use of a newly developed cinnamaldehyde product in commercial broiler production

Essential oils (EOs) have been considered as an alternative to antibiotics for animal production. In the current study, 4 trials were conducted on a commercial broiler farm to investigate the effects of dietary supplementation of an encapsulated cinnamon EO product (NE-OFF) on the bird growth performance, gut health, and gene expression in the ileum, spleen, and liver relating to the host response to heat and other stresses, including potential NE challenge. In each trial, approximately 30,000 Cobb or Ross broilers were randomly allocated to 4 treatments: a raised without antibiotics (RWA) commercial diet as positive control, an adjusted RWA commercial diet as negative control, and the negative control diet supplemented with 2 different dosages of NE-OFF, which was added during feed pelleting. Although the final average body weight did not differ significantly among treatment groups, birds fed NE-OFF had an increased ratio of villus height and crypt depth in the jejunum, and reduced fecal oocyst counts. Trial 2 was conducted in the summer and had a necrotic enteritis (NE) outbreak. The supplementation of NE-OFF reduced the NE incidence and bird mortality. The samples from Trial 2 were hence selected for the analyses of Clostridium perfringens and NetB toxin gene abundance in the ileum, and host responses. The C. perfringens population appeared to be positively correlated with the NetB gene abundance. The gene expression analysis suggested that NE-OFF supplementation improved nutrient absorption and transportation as well as antioxidant activities to help the birds against stress. These on-farm trial results support the hypothesis that the use of NE-OFF as a feed additive can improve bird gut health and performance in commercial broiler production, especially for preventing NE outbreaks when birds are under stress.

Effect of a microencapsulated phyto/phycogenic blend supplementation on growth performance, processing parameters, meat quality, and sensory profile in male broilers

Powered by consumer taste, value, and preferences, natural products including phytogenics and algae are increasingly and separately used in the food systems where they have been reported to improve growth performance in poultry and livestock. The present study aimed to determine the effects of a new feed additive, microencapsulated NUQO© NEX, which contains a combination of phytogenic and phycogenic, on broiler growth performance, blood chemistry, bone health, meat quality and sensory profile. Male Cobb500 chicks (n = 1,197) were fed a 3-phase feeding intervals; 1-14d starter, 15-28d grower, and 29-40d finisher. The dietary treatments included a corn-soy basal Control (CON), basal diet supplemented with NUQO© NEX at 100 g/ton from 1 to 28d then 75 g/ton from d 28 to 40 (NEX75), and basal diet supplemented with NUQO© NEX at 100 g/ton from 1 to 40d (NEX100). The NEX100 supplemented birds had 62 g more BWG increase and 2.1-point improvement in FCR compared with CON in the finisher and overall growth phase (p < 0.05), respectively. Day 40 processing body weights and carcass weights were heavier for the NEX100 supplemented birds (p < 0.05). The incidences of muscle myopathies were also higher in NEX treatments, which could be associated with the heavier weights, but the differences were not detected to be significant. The NEX75 breast filets had more yellowness than other dietary treatments (p = 0.003) and the NEX 100 treatment reduced the levels of breast filet TBARS at 7 days-post harvest (p = 0.053). Finally, both NEX treatments reduced the incidence of severe bone (tibia and femur) lesions. In conclusion, the supplementation of the phytogenic NUQO© NEX improved finisher performance parameters, whole phase FCR, processing carcass weights, and breast filet yellowness, at varying inclusion levels.

Coated oregano essential oil and cinnamaldehyde compounds supplementation improves growth performance, enhances immune responses, and inhibits cecal Escherichia coli proliferation of broilers

Plant essential oils are unstable due to high volatility and easy oxidation, while microencapsulation provides a potentially effective strategy for increasing the stability of natural essential oils and preserving their function. This study examined the effects of feeding coated oregano essential oil and cinnamaldehyde (COEC) compounds on growth, immune organ development, intestinal morphology, mucosal immune function, and the cecal microbiota populations of broilers. Three hundred one-day-old male Arbor Acres broiler chicks were organized into 5 groups: 1) negative control fed basal diet alone (NC), 2) positive control receiving basal diet plus 50 mg/kg of chlortetracycline (CTC), 3) basal diet plus 150 mg/kg COEC (COEC150), 4) plus 300 mg/kg COEC (COEC300), and 5) plus 450 mg/kg COEC (COEC450). The supplement trial was continued for 42 d. The results showed that CTC, COEC300, and COEC450 treatments decreased the feed conversion ratio of broilers both in the starter and whole experiment phases, increased the height of jejunal villi at 21 d and the number of goblet cells and IgA-producing cells at 21 or 42 d compared with NC group (P < 0.05). Members of the COEC300 treatment group had a higher thymus weight index and jejunum length index than birds of NC or CTC groups at 21 d (P < 0.05). CTC and all COEC treatments decreased malondialdehyde content in jejunal mucosa at 42 d (P < 0.05). The population of Escherichia coli (E. coli) in the cecal digesta at 21 d was lower in the CTC, COEC300, and COEC450 treatment groups compared with the NC group (P < 0.05). In contrast to the CTC group, COEC supplementation dose-dependently accelerated body weight gain, improved jejunal morphology, decreased malondialdehyde content in jejunal mucosa, increased numbers of jejunal goblet cells and IgA-producing cells, and decreased the E. coli population in cecal digesta at 21 or 42 d (P < 0.05). Thus, we concluded that feeding broiler chickens with 300 or 450 mg/kg in antibiotic-free diets can improve growth performance, enhance immune responses, and inhibit the proliferation of cecal pathogenic bacteria.

Effects of silybin supplementation on growth performance, serum indexes and liver transcriptome of Peking ducks

As an emerging feed additive extracted from the traditional herb milk thistle, silybin has few applications and studies in Peking ducks. The aim of this study was to explore the practical significance of silymarin application in Peking ducks and to provide more theoretical support for the application of silymarin in livestock and poultry production. A total of 156 1-day-old healthy Peking ducks were randomly divided into four groups and supplemented with 0 mg/kg (control group), 400 mg/kg (S400), 800 mg/kg (S800) and 1,600 mg/kg (S1600) of silybin in the diets at day 14, to investigate the effects of silymarin on the growth, serum indexes and liver transcriptome of Peking ducks. The whole experiment lasted until day 42, and the sample collection was scheduled to take place in the morning. A substantial inprovement in average daily gain (ADG) and a decrease in feed conversion ratio (FCR) occurred in the S1600 group on days 14-28 compared to the control group (p < 0.05). The FCRs of other additive groups in the same period showed the same results. Supplementation of diets with silybin significantly increased serum IgA levels and when 1,600 mg/kg of silybin was given, levels of TNF-α and IL-6 were also significantly decreased (p < 0.05). In addition, we observed that the S1600 group had a significantly lower (p < 0.05) glutamine transaminase and an increased (p < 0.05) T-SOD level in the S400 group (p < 0.05). Liver transcriptome sequencing showed that 71 and 258 differentially expressed genes (DEGs) were identified in the S400 and S1600 groups, respectively, compared with the control group. DEGs related to cell composition and function, antigen processing and presentation were up-regulated, while DEGs related to insulin resistance and JAK-STAT were down-regulated. Conclusively, silybin can be used as a feed additive to improve the growth performance and health status of Peking ducks.

Nutritional Strategies to Improve Meat Quality and Composition in the Challenging Conditions of Broiler Production: A Review

Poultry meat is becoming one of the most important animal protein sources for human beings in terms of health benefits, cost, and production efficiency. Effective genetic selection and nutritional programs have dramatically increased meat yield and broiler production efficiency. However, modern practices in broiler production result in unfavorable meat quality and body composition due to a diverse range of challenging conditions, including bacterial and parasitic infection, heat stress, and the consumption of mycotoxin and oxidized oils. Numerous studies have demonstrated that appropriate nutritional interventions have improved the meat quality and body composition of broiler chickens. Modulating nutritional composition [e.g., energy and crude protein (CP) levels] and amino acids (AA) levels has altered the meat quality and body composition of broiler chickens. The supplementation of bioactive compounds, such as vitamins, probiotics, prebiotics, exogenous enzymes, plant polyphenol compounds, and organic acids, has improved meat quality and changed the body composition of broiler chickens.

Effects of tannic acid supplementation on growth performance, gut health, and meat production and quality of broiler chickens raised in floor pens for 42 days

A study was conducted to investigate the effects of tannic acid (TA) supplementation on growth performance, gut health, antioxidant capacity, gut microbiota, and meat yield and quality in broilers raised for 42 days. A total of 700 one-day-old male broiler chickens (Cobb500) were allocated into 5 treatments with 7 replicates of 20 birds per pen. There were five treatments: 1) tannic acid 0 (TA0: basal diet without TA); 2) tannic acid 0.25 (TA0.25: basal diet+0.25 g/kg TA); 3) tannic acid 0.5 (TA0.5: basal diet+0.5 g/kg TA); 4) tannic acid 1 (TA1: basal diet+1 g/kg TA); and 5) tannic acid 2 (TA2: basal diet+2 g/kg TA). The dietary phases included starter (D 0 to 18; crumble feed), grower (D 18 to 28; pellet feed), and finisher (D 28 to 42; pellet feed). On D 18, the supplementation of TA linearly reduced body weight (BW) and average daily feed intake (ADFI) (p < 0.05), and on D 28, the supplementation of TA linearly reduced BW, average daily gain (ADG), and feed conversion ratio (FCR) (p < 0.05). Relative mRNA expression of genes related to mucin production (MUC2), tight junction proteins (CLDN2 and JAM2), and nutrient transporters (B0AT1 and SGLT1) was linearly increased by the supplementation of TA (p < 0.05). The supplementation of TA tended to linearly increase the relative abundance of the family Enterobacteriaceae (p = 0.08) and quadratically increased the relative abundance of the families Lachnospiraceae and Ruminococcaceae in the cecal microbial communities (p < 0.05). On D 36, the ratio of the phyla Firmicutes and Bacteroidetes was quadratically reduced by the supplementation of TA (p < 0.05). On D 42, bone mineral density and the lean to fat ratio were linearly decreased by the supplementation of TA (p < 0.05). On D 43, total chilled carcass weight was linearly reduced (p < 0.05), and proportion of leg weight was increased by supplementation of TA (p < 0.05). The supplementation of TA linearly reduced pH of the breast meat (p < 0.05) and linearly increased redness (a*) (p < 0.05). Although the supplementation of TA positively influenced gut health and gut microbiota in the starter/grower phases, it negatively affected overall growth performance, bone health, and meat production in broilers on D 42.

Effects of dietary trans-cinnamaldehyde on growth performance, lipid metabolism, immune response and intestinal microbiota of Litopenaeus vannamei

The purpose of this study was to evaluate the effects of dietary trans-cinnamaldehyde (TC) on growth performance, lipid metabolism, immune response and intestinal microbiota of Litopenaeus vannamei. Shrimp were randomly divided into 4 groups, with 3 replicants in each group and 70 shrimp in each replicant. The contents of TC in the four groups were 0, 0.4, 0.8 and 1.2 g kg^-1, respectively. Samples were taken after 56 days, followed by a 7-day vibrio harveyi challenge experiment. The results showed that TC significantly improved the growth performance by enhancing the activity of digestive enzymes in shrimp (P < 0.05). TC also reduced the content of crude fat (P < 0.05). The addition of TC to the diet attenuated lipid deposition, as evidenced by a reduction in the content of crude fat and a decrease in plasma levels of cholesterol and triglycerides (P < 0.05). The expression of key genes for fatty acid and triglycerides synthesis were significantly down-regulated and key genes for fatty acid β-oxidation were significantly up-regulated (P < 0.05). In addition, the immune response and antioxidant capability of shrimp were significantly enhanced by the addition of TC to the diet (P < 0.05). Meanwhile, TC could improve intestinal health by increasing the abundance of beneficial bacteria and decreasing the abundance of pathogenic bacteria, but had no significant effect on alpha diversity and beta diversity (P > 0.05). In addition, the results of histopathological sections and plasma transaminase studies showed that TC could improve the health status of hepatopancreas and was a safe nutritional supplement. After the 7-day Vibrio harveyi challenge, the cumulative mortality of shrimp decreased with increasing levels of dietary TC compared with control group (P < 0.05). These results suggested that TC could be used as a nutritional supplement for shrimp to enhance disease resistance and reduce lipid accumulation.

Gut Microbiome Studies in Livestock: Achievements, Challenges, and Perspectives

The variety and makeup of the gut microbiome are frequently regarded as the primary determinants of health and production performances in domestic animals. High-throughput DNA/RNA sequencing techniques (NGS) have recently gained popularity and permitted previously unheard-of advancements in the study of gut microbiota, particularly for determining the taxonomic composition of such complex communities. Here, we summarize the existing body of knowledge on livestock gut microbiome, discuss the state-of-the-art in sequencing techniques, and offer predictions for next research. We found that the enormous volumes of available data are biased toward a small number of globally distributed and carefully chosen varieties, while local breeds (or populations) are frequently overlooked despite their demonstrated resistance to harsh environmental circumstances. Furthermore, the bulk of this research has mostly focused on bacteria, whereas other microbial components such as protists, fungi, and viruses have received far less attention. The majority of these data were gathered utilizing traditional metabarcoding techniques that taxonomically identify the gut microbiota by analyzing small portions of their genome (less than 1000 base pairs). However, to extend the coverage of microbial genomes for a more precise and thorough characterization of microbial communities, a variety of increasingly practical and economical shotgun techniques are currently available.

Dietary Cinnamaldehyde Enhances Growth Performance, Digestion, Immunity, and Lipid Metabolism in Juvenile Fat Greenling (Hexagrammos otakii)

Fat greenling (Hexagrammos otakii) is a kind of economic fish that is widely consumed by human, and its intensive farming technology is making important progress. However, high-density farming may cause the occurrence of diseases in H. otakii. Cinnamaldehyde (CNE) is a new feed additive for aquatic animals and has a positive effect on disease resistance. In the study, dietary CNE was evaluated on the growth performance, digestion, immune response, and lipid metabolism of juvenile H. otakii (6.21 ± 0.19 g). Six experimental diets were formulated containing CNE at levels of 0, 200, 400, 600, 800, and 1000 mg/kg for 8 weeks. The percent weight gain (PWG), specific growth rate (SGR), survival (SR), and feeding rate (FR) were significantly increased by including CNE in fish diets regardless of the inclusion level (P < 0.05). The feed conversion ratio (FCR) was significantly decreased among the groups fed CNE supplemented diets (P < 0.05). A significant decrease in hepatosomatic index (HSI) was observed in fish fed 400 mg/kg-1000 mg/kg CNE compared to the control diet (P < 0.05). Fish-fed diets containing 400 mg/kg and 600 mg/kg CNE had a higher level of crude protein in muscles than the control diet (P < 0.05). Moreover, the activities of lipase (LPS) and pepsin (PEP) in the intestinal were markedly increased in juvenile H. otakii-fed dietary CNE (P < 0.05). Apparent digestibility coefficient (ADC) of dry matter, protein, and lipid was significantly increased with CNE supplement (P < 0.05). The activities of catalase (CAT) and acid phosphatase (ACP) in the liver were markedly enhanced by including CNE in juvenile H. otakii diets compared with the control (P < 0.05). The activities of superoxide dismutase (SOD) and alkaline phosphatase (AKP) in the liver were markedly enhanced in juvenile H. otakii treated with CNE supplements 400 mg/kg-1000 mg/kg (P < 0.05). Additionally, the levels of total protein (TP) in the serum were markedly increased by including CNE in juvenile H. otakii diets compared with the control (P < 0.05). In the CNE200, CNE400, and CNE600 groups, albumin (ALB) levels in the serum were markedly higher compared with that in the control (P < 0.05). In the CNE200 and CNE400 groups, the levels of immunoglobulin G (IgG) in the serum were significantly increased compared with that the control group (P < 0.05). The juvenile H. otakii-fed dietary CNE had lower triglycerides (TG) and total cholesterol (TCHO) levels in the serum than fish-fed CNE-free diets (P < 0.05). The gene expression of peroxisome proliferator-activated receptor alpha (PPAR-α), hormone-sensitive lipase (HSL), and carnitine O-palmitoyltransferase 1 (CPT1) in the liver was significantly increased by including CNE in fish diets regardless of the inclusion level (P < 0.05). However, fatty acid synthase (FAS), peroxisome proliferator-activated receptor gamma (PPAR-γ), and acetyl-CoA carboxylase alpha (ACCα) in the liver were markedly decreased with CNE supplements 400 mg/kg-1000 mg/kg (P < 0.05). The glucose-6-phosphate1-dehydrogenase (G6PD) gene expression levels in the liver were markedly decreased compared with the control (P < 0.05). The optimal supplementation level of CNE was shown by curve equation analysis to be 590.90 mg/kg.

Dietary cinnamaldehyde with carvacrol or thymol improves the egg quality and intestinal health independent of gut microbiota in post-peak laying hens

Essential oils have been proven to exert multiple effects on growth performance, production quality, and health status in poultry nutrition, which is dependent on the component and/or dose of essential oils. Diets with the optimal combination of essential oils might be able to improve the performance traits and welfare of laying hens. Therefore, this study was conducted to evaluate the effects of dietary essential oils, which are composed of cinnamaldehyde with carvacrol or thymol, on performance, egg quality, and intestinal health in post-peak laying hens. A total of 384, 50-week-old Hy-line brown laying hens were randomly divided into three groups with 8 replicates of 16 birds each: (1) a basal diet (Ctrl), (2) a basal diet with 100 mg/kg of essential oils consisting of 4.5% cinnamaldehyde with 13.5% carvacrol (CAR+CIN), and (3) a basal diet containing 100 mg/kg of essential oils composed of 4.5% cinnamaldehyde with 13.5% thymol (THY+CIN). The CAR+CIN diet increased the feed consumption from 52 to 55 weeks more than the Ctrl and the THY+CIN diet. Compared with the Ctrl group, the addition of essential oils decreased the dirty egg rate (P = 0.07) in the whole trial period. Regarding egg quality, the birds that received the CAR+CIN and THY+CIN diets increased the eggshell strength (P = 0.099) or Haugh unit (HU, p = 0.03) at 54 weeks, respectively. Supplementation of both CAR+CIN and THY+CIN diets significantly increased the ratio of villus height to crypt depth in the duodenum through increasing villus height and decreasing crypt depth as well as upregulated the mRNA abundances of duodenal occluding and cadherin (P < 0.05). However, the treatment with dietary essential oils did not notably change the proportion of cecal microbiota and bacterial diversity. This study suggested that dietary supplementation of cinnamaldehyde with carvacrol or thymol, the active components of essential oils, could promote egg quality in post-peak laying hens, which might be associated with improved intestinal development and barrier.

Bioactive compounds, antibiotics and heavy metals: effects on the intestinal structure and microbiome of monogastric animals – a non-systematic review

The intestinal structure and gut microbiota are essential for the animals‘ health. Chemical components taken with food provide the right environment for a specific microbiome which, together with its metabolites and the products of digestion, create an environment, which in turn is affects the population size of specific bacteria. Disturbances in the composition of the gut microbiota can be a reason for the malformation of guts, which has a decisive impact on the animal‘ health. This review aimed to analyse scientific literature, published over the past 20 years, concerning the effect of nutritional factors on gut health, determined by the intestinal structure and microbiota of monogastric animals. Several topics have been investigated: bioactive compounds (probiotics, prebiotics, organic acids, and herbal active substances), antibiotics and heavy metals (essentaial minerals and toxic heavy metals).

Encapsulation as a way to improve the phytogenic effects of herbal additives in broilers – an overview

The prohibition of antibiotic growth promoters (AGP) and the restriction of synthetic antioxidants have had a negative impact on the productivity and health of broiler chickens. To ensure sustainability in broiler production, poultry nutritionists continue to look for alternatives to AGP and antioxidants. Using herbal ingredients is one alternative that is widely used today. However, the use of herbal ingredients in small doses is often constrained by bioavailability problems, thereby reducing the effectiveness of using herbal additives for broiler chickens. At higher doses, the use of herbal ingredients can increase feed costs and negatively impact palatability, digestion and protein utilization, and liver health. Encapsulation is a method that can improve the stability, palatability, and bioavailability of herbal additives, which may enhance the efficacy of herbs as AGP and antioxidant alternatives for broilers. This review article provides a comprehensive insight into the application of and problems related to herbal additives, benefits of encapsulation technology on herbs, and use of encapsulated herbs in broiler production.

Effects of supplemental tannic acid on growth performance, gut health, microbiota, and fat accumulation and optimal dosages of tannic acid in broilers

This study was conducted to investigate the effects of different dosages of tannic acid (TA) on growth performance, nutrient digestibility, gut health, immune system, oxidative status, microbial composition, volatile fatty acids (VFA), bone mineral density, and fat digestion and accumulation in broilers and to find optimal dosages of TA for efficient growth and gut health in broilers. A total of 320 male Cobb500 broilers were randomly distributed to 4 treatments with 8 replicates including 1) tannic acid 0 (TA0): basal diet without TA; 2) tannic acid 0.5 (TA0.5): basal diet with 0.5 g/kg TA; 3) tannic acid 1.5 (TA1.5); and 4) tannic acid 2.5 (TA2.5). Supplemental TA at levels greater than 972 mg/kg tended to reduce BW on D 21 (p = 0.05). The TA2.5 had significantly lower apparent ileal digestibility (AID) of crude protein compared to the TA0 group. The AID of ether extract tended to be reduced by TA at levels greater than 525 mg/kg (p = 0.08). The jejunal lipase activities tended to be reduced by TA at levels less than 595.3 mg/kg (p = 0.09). TA linearly decreased goblet cell density in the crypts of the jejunum (p < 0.05) and reduced mRNA expression of mucin two at levels less than 784.9 mg/kg and zonula occludens two at levels less than 892.6 mg/kg (p < 0.05). The TA0.5 group had higher activities of liver superoxide dismutase compared to the TA0 group (p < 0.05). Bone mineral density and contents tended to be linearly decreased by TA (p = 0.05), and the ratio of lean to fat was linearly decreased (p < 0.01). Total cecal VFA production tended to be linearly reduced by TA at levels greater than 850.9 mg/kg (p = 0.07). Supplemental TA tended to increase the relative abundance of the phylum Bacteroidetes (p = 0.1) and decrease the relative abundance of the phylum Proteobacteria (p = 0.1). The relative abundance of the family Rikenellaceae was the lowest at 500 mg/kg TA, and the relative abundance of the family Bacillaceae was the highest at 1,045 mg/kg TA. Collectively, these results indicate that the optimum level of supplemental TA would range between 500 and 900 mg/kg; this range of TA supplementation would improve gut health without negatively affecting growth performance in broilers under antibiotic-free conditions.

Application of Organic Acids and Essential Oils as Alternatives to Antibiotic Growth Promoters in Broiler Chickens

This study was conducted to evaluate the effects of OAs and EOs on growth performance, serum biochemistry, antioxidant enzyme activities, intestinal morphology, and digestive enzyme activities to replace AGP in broilers. Six hundred one-day-old broilers were allotted to five treatments with six replicates: (1) negative control (NC; basal diet); (2) positive control (PC; NC + 50 mg/kg bacitracin methylene disalicylate); (3) organic acids (OA; NC + 2000 mg/kg OA); (4) essential oils (EO; NC + 300 mg/kg EO); and (5) OA + EO (NC + 2000 mg/kg OA + 300 mg/kg EO). In the starter phase, the PC, EO, and OA + EO groups had a significantly lower feed conversion ratio (FCR) compared to the NC group. While the final body weight (BW) of broilers fed OAs was similar compared to broilers fed PC (p > 0.1), the FCR of the OA group tended to be lower than the PC group on D 42 (p = 0.074). The OA group had the higher serum GLOB:ALB (albumin) and ileal villus height and crypt depth (VH:CD) ratios compared to the EO group. Thus, the supplementation of EOs and OAs could substitute AGP in the starter and finisher phase, respectively.