Assessment of a phytogenic feed additive effect on broiler growth performance, nutrient digestibility and caecal microflora composition

Economic and Productive Comparison of Rutin and Rutin-Loaded Chitosan Alginate Nanoparticles Against Lead-Induced Oxidative Stress in Cobb and Arbor Broiler Breeds

Rutin, a natural bioflavonoid compound, is one of the best-known antioxidants. This study aimed to investigate the protective effect of rutin-loaded chitosan alginate nanoparticles (RCA NPs) against lead (Pb)-induced oxidative stress in two different broiler breeds. A total number of 240 chicks from Cobb (CB) and Arbor Acres (AR) breeds were randomly allocated into 4 groups/breed. The 1st group received standard basal diet (SD) and drinking water (DW) while the 2nd group received SD and Pb-incorporated DW (350 mg/L). The 3rd group treated with both rutin-supplemented SD (50 mg/kg feed), and DW contain Pb (350 mg/L). Finally, the 4th group administered RCA NPs-supplemented SD (50 mg/kg feed) and Pb-incorporated DW (350 mg/L). On the 40th day of experiment, broilers weighed, and blood samples collected for biochemical and hematological analysis then slaughtered. Economic efficiency, growth performance, and oxidative stress biomarkers were evaluated. Gene expression level of growth-associated genes as insulin-like growth factor-I (IGF-1) and histopathological changes were assessed in liver and intestinal tissue of both breeds. Our results revealed that Pb-treated birds exhibited the lowest average body weight gain (BWG) and economic efficiency measures in both breeds while RCA NPs-treated groups revealed enhanced growth and economic performance. Furthermore, diet supplementation with RCA NPs considerably enhanced the antioxidant enzymes activity and expression of growth-associated genes than groups treated with rutin alone specifically in AR breed. In conclusion, RCA NPs supplementation could be a promising nanoformulation in poultry production through enhancing the antioxidant capacity and bioavailability of rutin.

Pulsed electric field (PEF) processing of microalga Chlorella vulgaris and its digestibility in broiler feed

Microalgae have potentially beneficial effects on animal health and nutritional value when added to feed. Crucial hereby is that intracellular bio-active molecules are released in the intestinal tract. Digestibility of Chlorella vulgaris and its impact on total digestibility of broiler feed is a first step in assessing its characteristics as feed supplement. Different methods could be used to increase the digestibility of the algae. Among other, pulsed electric field (PEF) and freezing to disrupt autotrophic (A) and heterotrophic (H) Chlorella vulgaris cells was assessed to increase their availability followed by in-vivo trials. In these trials effect of algae type (A and H) and effect of PEF-processing was evaluated on the apparent nutrient digestibility. Pulsed electric field showed to have a disruption efficiency of 83.90% and 79.20% for heterotrophic and autotrophic C. vulgaris respectively. Freezing C. vulgaris only showed efficiencies ranging from 3.86 to 11.58%. In the in-vivo trials, microscopic counting of intact C. vulgaris cells showed an increase in digested intact C. vulgaris cells of PEF-processed C. vulgaris compared to nonprocessed cells ranging from 12.16% to 15.20%. Autotrophic C. vulgaris had a higher digestibility compared to heterotrophic C. vulgaris, with an increase of 7.29, 9.44, and 17.29% in digestibility of C. vulgaris in the 1, 2, and 5% feed respectively. Feeds with PEF-processed C. vulgaris showed no significant increase in digestibility compared to nonprocessed C. vulgaris supplemented feeds. The 5% C. vulgaris feeds showed lower fat digestibility than the 1 and 2% and control feeds. Protein digestibility was lower for all C. vulgaris feeds compared to the control feed. There was a significant linear decreasing effect (P < 0.001) for all digestibility parameters. Except for crude ash digestibility, which first lowered for the 1 and 2% feeds, but then increased at 5% inclusion. Considering this study, including low dosages of 1 and 2% of C. vulgaris in broiler feed does not compromise its digestibility.

Impact of Nanoencapsulated Rosemary Essential Oil as a Novel Feed Additive on Growth Performance, Nutrient Utilization, Carcass Traits, Meat Quality and Gene Expression of Broiler Chicken

This study evaluated the effect of free and nanoencapsulated rosemary essential oil (REO) as an antibiotic alternative in broiler diets on growth performance, nutrient digestibility, carcass traits, meat quality and gene expression. Four hundred twenty day-old commercial broiler chicks (VENCOBB) were randomly allocated to seven dietary treatments, each having four replicates of fifteen chicks. The dietary treatments comprised control (CON) fed a basal diet only, AB (basal diet + 10 mg enramycin/kg), CS (basal diet + 150 mg chitosan nanoparticles/kg), REOF100 and REOF200 (basal diet + 100 mg and 200 mg free REO/kg, respectively), and REON100 and REON200 (basal diet + 100 mg and 200 mg nanoencapsulated REO/kg, respectively). Overall (7-42 d), REON200 showed the highest (p < 0.001) body weight gain (1899 g/bird) and CON had the lowest gain (1742 g/bird), while the CS, REOF100 and REOF200 groups had a similar gain, but lower than that of the AB and REON100 groups. Feed intake was not affected by dietary treatments. Overall, the feed efficiency increased (p = 0.001) by 8.47% in the REON200 group and 6.21% in the AB and REON100 groups compared with the CON. Supplementation of REO improved (p < 0.05) dry matter and crude protein digestibility, with the highest values in REON100 and REON200. Ether extract, crude fiber, calcium and phosphorus digestibility values showed no difference among the groups. The dressing, breast, thigh % increased (p < 0.05) and abdominal fat % decreased (p < 0.001) more in the REON200 group than with other treatments and CON. In breast meat quality, water holding capacity and extract reserve volume increased (p < 0.05) while drip loss and cholesterol content decreased (p < 0.05) in REON100 and REON200. No change was observed in the breast meat color among dietary treatments and CON. The REON100 and REON200 groups had reduced (p < 0.05) meat lipid peroxidation as depicted by the decreased levels of TBARS, free fatty acids and peroxide value compared to other treatments and CON. The expression of the Mucin 2, PepT1 and IL-10 genes was upregulated (p < 0.001) and TNF-α downregulated (p < 0.001) by dietary addition of REO particularly in the nanoencapsulated form compared with the CON. In conclusion, nanoencapsulated REO, especially at 200 mg/kg diet, showed promising results as an antibiotic alternative in improving the performance, nutrient digestibility, carcass traits, meat quality and upregulation of growth and anti-inflammatory genes.

Assessing the potential of phytogenic feed additives: A comprehensive review on their effectiveness as a potent dietary enhancement for nonruminant in swine and poultry

Phytogenic feed additives (PFAs) often referred to as phytobiotics or botanical feed additives, are natural compounds derived from various plants, herbs, spices and other botanical sources. These feed additives are intended to serve a variety of purposes, including an immune system regulator, an antimicrobial, an antimutagenic, an antioxidant and a growth promoter. They are composed of bioactive compounds extracted from plants, including essential oils, polyphenols, terpenoids and flavonoids. They are mostly utilized as substitute antibiotic growth promoters in nonruminant (swine and poultry) livestock production, owing to the prohibition of antibiotic usage in the feed industry. It has been thoroughly examined to ascertain their impact on intestinal health and activity, correlation with animals' effective health and well-being, productivity, food security and environmental impact. The potential uses of these feed additives depend on the properties of herbs, the comprehension of their principal and secondary components, knowledge of their mechanisms of action, the safety of animals and the products they produce. They are gaining recognition as effective and sustainable tools for promoting animal health and performance while reducing the reliance on antibiotics in nonruminant nutrition. Their natural origins, multifaceted benefits and alignment with consumer preferences make them a valuable addition to modern animal farming process. However, because of their inconsistent effects and inadequate knowledge of the mechanisms of action, their usage as a feed additive has been limited. This review offers a comprehensive assessment of the applications of PFAs as an effective feed supplement in swine and poultry nutrition. In summary, this comprehensive review provides current knowledge, identifies gaps in research and emphasizes the potential of phytogenic additives to foster sustainable and healthier livestock production systems while addressing the global concerns associated with antibiotic use in livestock farming.

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.

Dietary supplement of fermented grass forage regulates growth performance, antioxidant capacity, and immune response of broiler chickens

The current study aimed to determine the effects of different levels of fermented Juncao grass (FG) on growth parameters, blood constituents, immunity, and antioxidative properties of broilers. A total of 240 (21-d-old) broiler chicks were randomly distributed to four dietary treatments of sixty birds, with six replicate pens and ten birds in each. Fermented grass was added to the basal diet at four levels with 0, 5, 10, and 15% FG. The results revealed that broilers fed 5% FG had significantly higher (P < 0.05) final body weight (FBW), average daily gain (WG) and average daily feed intake (ADFI). The best conversion ratio (FCR) was recorded for broilers supplemented with 5% FG compared to the group supplemented with 15% FG (P < 0.05). Increasing FG % decreased (P < 0.05) anti-inflammatory cytokines IL-4, IL-6, and IL-10. However, FG increased (P < 0.05) proinflammatory cytokines IFN-γ, IL-1, IL-2, IL-12, and TNF-α (P < 0.05). Moreover, IgA, IgG, and IgM levels increased (P < 0.05) with increasing FG %. In addition, increasing FG % in broiler rations significantly increased (P < 0.05) serum antioxidant levels of T-AOC, GSH-PX, SOD, CAT, NO and GSH, but decreased (P < 0.05) MDA levels compared to the control group. Conclusively, fermented Juncao grass would be considered a novel herbal feed additive for improving broiler performance, immunity, antioxidant, and health status. Nevertheless, further research at the molecular level is needed to quantify the effects of these herbal components on cellular and humoral immune functions in broiler chickens.

Modulation of Immune Response and Cecal Microbiota by Dietary Fenugreek Seeds in Broilers

Fenugreek seeds (FSs) are a natural source of bioactive compounds that may modulate the immune system and gut microbiota in broilers. This study examined the effects of dietary fenugreek seed powder on immune-related gene expression and cecal microbiota composition in broilers. A total of 144 broiler chickens were randomly allocated to three dietary groups, CON (0 g/kg FS, FS5 (5 g/kg FS) and FS10 (10 g/kg FS), each with 6 replicates of 8 birds. Ileum tissues and cecal contents were collected on day 42 for the mRNA expression of inflammation and antimicrobial defense-related genes and cecal microbiome diversity, respectively. The results indicated that fenugreek seeds downregulated mRNA-level inflammation and antimicrobial defense-related genes: IL6, IL8L2, CASP6, PTGS2, IRF7, AvBD9, AvBD10, and AvBD11. Moreover, fenugreek seeds altered the cecal microbial community by increasing the population of Firmicutes and decreasing the population of Actinobacteriota, Gemmatimonadota and Verrucomicrobiota at the phylum level and increasing Alistipes, Bacteriodes and Prevotellaceae at the genera level. These findings suggest that fenugreek seeds have a positive impact on the immunological profile and microbiome of broiler chickens, possibly through the interplay of the immune system and the gut microbiome.

Dietary Inclusion Level Effects of Yoghurt Acid Whey Powder on Performance, Digestibility of Nutrients and Meat Quality of Broilers

In recent years, the increasing demand for Greek strained yoghurt produced massive amounts of acid whey, which constitutes a major environmental pollutant. Whether yoghurt acid whey can be included in poultry diets is not known. The purpose of this study was to evaluate the effects of four dietary levels of yoghurt acid whey powder (YAWP) on the growth performance, nutrient digestibility, meat quality traits and oxidative stability. A total of 300 male 1-day-old Ross 308 broilers were assigned into four groups with five replicates of 15 broilers each: control-fed basal diet with no YAWP addition (WO) or basal diet supplemented with YAWP at 25 g/kg of diet (WA), 50 g/kg of diet (WB), or 100 g/kg of diet (WC). At the starter period, body weight and body weight gain were reduced after WB and WC treatments compared to the WO treatment. Breast meat oxidative stability was improved during refrigerated storage for 1 and 3 d in all YAWP treatments compared to control, while the WA treatment showed an improved oxidative stability after 6 and 9 d. The results suggest that YAWP inclusion at 25 g/kg of diet did not impair performance and extended the meat shelf life by reducing lipid oxidation rates.

Red osier dogwood and its use in animal nutrition: A review

As the human population increases globally, the food animal industry has not been spared from the monumental demand for edible animal products, particularly meat. This has necessitated the simultaneous expansion of the productivity of the animal sector to meet the ever-growing human needs. Although antibiotics have been used in food animal production with commendable positive impacts on their growth performance, their sole contributive factor to the increasing incidence of antimicrobial resistance has ushered the strict restrictions placed on their use in the animal sector. This has handed a setback to both animals and farmers; thus, the intense push for a more sustainable antibiotic alternative for use in animal production. The use of plants with concentrated phytogenic compounds has gained much interest due to their beneficial bioactivities, including antioxidant and selective antimicrobial. While the reported beneficial activities of phytogenic additives on animals vary due to their varying total polyphenol concentrations (TPC), red osier dogwood (ROD) plant materials boast of high TPC with excellent antioxidant prowess and growth improvement capacities compared to some plant extracts commonly used in research. However, its adoption in research and commercial scale is still low. Thus, the present review aims to provide concise information on the dietary potential of ROD plant materials in animal feeding.

Nutrigenomic profiling of reduced specification diets and phytogenic inclusion effects on critical toll-like receptor signaling, mitogen-activated protein kinase-apoptosis, and PI3K-Akt-mTOR gene components along the broiler gut

The effects of concurrent reduction of dietary metabolizable energy (ME) and crude protein (CP) levels combined or not with the dietary inclusion of a phytogenic feed additive (PFA) were studied using a nutrigenomics approach. In particular, the expression of 26 critical genes relevant for inflammation control (TLR pathway), cellular apoptosis (MAPK pathway) cell growth and nutrient metabolism (PI3K-Akt-mTOR pathway) was profiled along the broiler intestine. Two dietary types (L and H) differing in metabolizable energy and crude protein levels (L: 95% and H: 100% of optimal Cobb 500 recommendations for ME and CP requirements) supplemented or not with PFA (- or +) and their interactions (L-, L+, H-, H+) were evaluated. There were only 3 total interactions (mTOR, IL8, and HRAS P < 0.05) between diet type and PFA inclusion indicating limited concurrent effects. Diet type, L upregulated genes related with inflammation mainly in the jejunum, ileum, and cecum (P < 0.05) and MAPK pathway in the ileum and cecum (P < 0.05). Moreover, diet type L negatively affected the expression of genes related to PI3K-Akt-mTOR pathway mainly in duodenum and cecum (P < 0.05). On the other hand, PFA inclusion downregulated (P < 0.05) genes related with TLR signaling pathway (TLR2B, MyD88, TLR3, IL8, LITAF) along the intestine and MAPK pathway genes (APO1, FOS) in jejunum (P < 0.05). Finally, PFA supplementation regulated nutrient sensing and metabolism in the cecum in a manner perceived as beneficial for growth. In conclusion, the study results highlight that the reduced ME and CP specifications, especially in the absence of PFA, regulate inflammation, apoptosis and nutrient metabolism processes at homeostatic control levels that hinder maximizing the availability of dietary energy and nutrients for growth purposes. Inclusion of PFA helped to adjust the respective homeostatic responses and control to levels supporting broiler performance, especially at reduced specification diets.

Novel Antioxidant Insights of Myricetin on the Performance of Broiler Chickens and Alleviating Experimental Infection with Eimeria spp.: Crosstalk between Oxidative Stress and Inflammation

In the modern poultry industry, the application of novel phytogenic bioactive compounds with antioxidant potential aims to enhance productivity and quality and to minimize the stress of associated diseases. Herein, myricetin, a natural flavonoid, was evaluated for the first time on broiler chickens' performance, antioxidants and immune modulating functions, and tackling avian coccidiosis. A total of 500 one-day-old chicks were divided into five groups. The negative (NC) and infected control (IC) groups were fed a control diet without additives, and the latter was infected with Eimeria spp. Groups supplemented with myricetin (Myc) were fed a control diet of Myc (200, 400 and 600 mg/kg diet each). On d 14, all chicks except those in NC were challenged with oocysts of mixed Eimeria spp. Significant improvements in the overall growth rate and feed conversion ratio were detected in the group that was fed 600 mg/kg, unlike the IC group. Notably, groups that were fed 400 and 600 mg/kg showed higher total meat antioxidant capacity with an inverse reduction in oxidative and lipid peroxidation biomarkers (hydrogen peroxide: H₂O₂; reactive oxygen species: ROS; Malondialdehyde: MDA). Of note, the upregulation of glutathione peroxidase; GSH-Px, catalase; CAT, superoxide dismutase; SOD, heme oxygenase-1; HO-1 and NAD(P)H dehydrogenase quinone 1 NQO1 genes in jejunum and muscle were prominently observed with increasing levels of supplemental Myc. At 21 dpi, the severity of coccoidal lesions (p < 0.05) induced by mixed Eimeria spp. and oocyst excretion were greatly reduced in the group that was fed 600 mg/kg of Myc. In the IC group, higher serum levels of C-reactive protein; CRP and nitric oxide; and NO and the upregulated expression of inflammatory biomarkers (interleukin-1β; IL-1β, interleukin-6; IL-6, tumor necrosis factor-α; TNF-α, chemotactic cytokines; CCL20, stromal cell-derived factor-1; CXCL13, and avian defensins; AvBD612) were subsided in higher levels in the Myc-fed groups. Taken together, these findings indicate the promising antioxidant role of Myc in modulating immune responses and reducing growth depression associated with coccidia challenges.

Dietary protocatechuic acid ameliorates ileal mucosal barrier injury and inflammatory response and improves intestinal microbiota composition in Yellow chickens challenged with Salmonella typhimurium

Salmonella typhimurium (ST) is a common foodborne pathogen that severely affects the health of humans and livestock. Protocatechuic acid (PCA) has been shown to possess anti-inflammatory and anti-bacterial functions. Chickens were used to investigate the effect of PCA on the gut health infected with ST. A total of one hundred eighty, 1-d-old birds were randomly allocated into 3 treatments, each with 6 replicates per treatment and 10 chicks per replicate. Broiler chicks in the control and ST treatment were fed a basal diet, and birds in the PCA+ST treatment received the basal diet with 600 mg/kg PCA. On d 14 and 16 of the trial, broilers in ST and PCA+ST treatments received an oral dose of ST, while broilers in CON received an equal amount of PBS. The data were analyzed by the one-way ANOVA. Dietary PCA increased (P < 0.05) final body weight, average daily gain, and feed to gain ratio in ST-challenged Yellow broilers. Protocatechuic acid significantly alleviated ST-induced intestinal mucosal injury reflected in the decreased (P < 0.05) plasma activity of diamine oxidase and ileal apoptosis, with increased (P < 0.05) ileal villus height and villus height/crypt depth. Protocatechuic acid treatment significantly decreased (P < 0.05) ST-induced proinflammatory cytokine (Interleukin-1β, Interleukin-6, Tumor necrosis factor-α, and Interferon-β) content in ileum. Meanwhile, PCA treatment significantly increased (P < 0.05) the transcript abundances of claudin 1 (CLDN1), zonula occludens-1 (ZO-1), and mucin 2 (MUC2) in ileum, all related to the intestinal barrier in ST-challenged Yellow broilers. Additionally, PCA also increased (P < 0.05) the diversity and richness of the cecal microflora as reflected by reduced (P < 0.05) abundance of Bacteroidota, Proteobacteria and Escherichia-Shigella, and increased (P < 0.05) abundance of Firmicutes and Lactobacillus in ST-challenged Yellow broilers. These findings indicate that PCA relieves ST-induced loss weight, intestinal barrier injury, inflammatory response, and improves intestinal microbiota composition in Yellow broilers.

Growth-stimulating and antioxidant effects of vanillic acid on healthy broiler chickens

Background and Aim

Phytobiotics are a safe alternative to feed antibiotics in industrial poultry farming that increases productivity by stimulating various digestive enzymes to reduce the number of pathogenic microorganisms in the intestines and improve antioxidant status and immune response. This study aimed to evaluate the effect of vanillic acid in its pure form and in combination with gamma lactone on weight growth and the physiological parameters of broiler chickens.

Materials and Methods

The studies were performed on 120 Arbor Acres broiler chickens (7 days old) that were randomly divided into four groups with five replicates (cages) and six birds per replicate. The control group was fed the basal diet (BD) only. Group I was fed the BD + gamma lactone (average dose 0.07 mL/animal/day). Group II was fed the BD + vanillic acid (average dose 0.07 mL/animal/day). Group III was fed the BD + gamma lactone + vanillic acid in a 1:1 ratio (average dose 0.07 mL/body/day). Live weight of broiler chickens for all group was assessed at the end of each period (age of 7, 14, 21, 28, 35, 42 days). At the end of the experiment (on day 42), 10 broilers with an average live weight were selected for blood sampling from the axillary vein.

Results

The results showed a growth-promoting effect of vanillic acid when fed with a diet free of synthetic antioxidants. Groups I and II had increased live weights throughout the entire experiment and a significant increase at the end of the experiment (8.2%-8.5%; p ≤ 0.05) compared to the control group. Toxic effects were not found in the biochemical blood serum analyses of Groups II and III. The metabolic processes in the experimental groups were intensified, especially in the enzyme associated with amino acid metabolism (gamma-glutamyl transferase) in Groups I and III (p ≤ 0.05). Vanillic acid, whether fed alone or in combination with gamma lactone, exhibited high antioxidant activities, protected cells from oxidative damage by inducing total antioxidant, catalase, and superoxide dismutase activities (p ≤ 0.05), and reduced the level of malondialdehyde (p ≤ 0.05) measured. No significant changes in the morphological blood parameters were found.

Conclusion

The use of vanillic acid alone and in combination with gamma lactone increases the digestive enzyme activities in blood plasma, increases body weight, and has a positive effect on lipid metabolism and the antioxidant status of broiler chickens. These findings indicate the significant potential use of vanillic acid and gamma lactone in poultry due to their antioxidant properties.

Application of botanical products as nutraceutical feed additives for improving poultry health and production

Poultry is one of the most consumed sources of animal protein around the world. To meet the global demands for poultry meat and eggs, it is necessary to improve their nutrition to sustain the poultry industry. However, the poultry industry faces several challenges, including feedstuff availability, the banning of antibiotics as growth promoters, and several environmental stressors. Therefore, there is a critical need to include available nutraceuticals in the diet to sustain the poultry industry. Nutraceuticals are natural chemical substances that positively influence animal physiological and productive traits. Botanical products (such as fenugreek seeds, ginger roots, and olive leaves) are among the most commonly used nutraceuticals and are gradually gaining popularity in the poultry industry due to their immense benefits in nutrition and therapeutic properties. They can be added to the diet separately or in combination (as a natural antioxidant and immunostimulant) to improve poultry health and production. Botanical products are rich in essential oils and essential fatty acids, which have multiple benefits on the animal's digestive system, such as activating the digestive enzymes and restoring microbiota balance, enhancing poultry health, and production. These nutraceuticals have been shown to stimulate the expression of several genes related to growth, metabolism, and immunity. In addition, the essential oil supplementation in poultry diets up-regulated the expression of some crucial genes associated with nutrient transportation (such as glucose transporter-2 and sodium-glucose cotransporter-1). Previous studies have suggested that supplementation of botanical compounds increased broiler body weight and hen egg production by approximately 7% and 15%, respectively. Furthermore, the supplementation of botanical compounds enhanced the reproductive efficiency of hens and the semen quality of roosters by 13%. This review article discusses the significant effects of some botanical products in the poultry industry and how they can benefit poultry, especially in light of the ban on antibiotics as growth promoters.

Dietary and phytogenic inclusion effects on the broiler chicken cecal ecosystem

Dietary modulation in broilers is crucial for the establishment of beneficial microbiota and, subsequently, the promotion of intestinal health. In this trial, a 2 × 2 factorial design was used with two different specifications with respect to dietary metabolizable energy (ME) and crude protein (CP) levels (i.e., 95% and 100% of recommendations) and phytogenic levels (0 and 150 mg/kg). Levels of total bacteria, Bacteroides spp., Lactobacillus spp., and Clostridium cluster XIVa attached to the cecal mucosa and in the cecal digesta were lower in broilers fed the 95% ME and CP specification diets, as was the molar ratio of butyric acid. In addition, the relative activity of autoinducers-2 (AI-2) and the expression levels of TLR4 and AvBD6 were increased. Phytogenic supplementation reduced cecal digesta levels of Escherichia coli and Clostridium cluster I levels, and increased Clostridium cluster IV levels. Moreover, the butyric acid molar ratio and the relative activity of AI-2 were increased, whereas the concentration of branched VFAs and the expression of AvBD6 and LEAP2 were reduced by phytogenic administration. Dietary specifications and phytogenic interactions were shown for the cecal-attached microbiota composition, metabolic activity of digesta microbiota, relative expression of autoinducers-2, and relative expression of toll-like signaling molecules and host antimicrobial peptides. In conclusion, it has been shown that ME and CP dietary specifications, combined or not with phytogenics, modulate multilevel gut biomarkers ranging from microbiota composition and metabolic activity to microbial communications and host signaling, inflammation, and defense.

Metatranscriptomic Analysis of the Chicken Gut Resistome Response to In-Feed Antibiotics and Natural Feed Additives

The emergence of resistance against common antibiotics in the gut microbiota is a major issue for both human and livestock health. This highlights the need for understanding the impact of such application on the reservoir of antibiotic resistance genes in poultry gut and devising means to circumvent the potential resistome expansion. Phytogenic feed additives (PFAs) are potential natural alternative to antibiotic to improve animal health and performance, supposedly via positively affecting the gut microbial ecosystem, but there is little systematic information available. In this time-course study, we applied a shotgun meta-transcriptomics approach to investigate the impact of a PFA product as well as the commonly used antibiotic, zinc bacitracin either at AGP concentration or therapeutic concentration on the gut microbiome and resistome of broiler chickens raised for 35 days. Over the course of the trial, PFA treatments increased the abundance of Firmicutes such as Lactobacillus and resulted in a lower abundance of Escherichia, while the latter group increased significantly in the feces of chickens that received either AGP or AB doses of bacitracin. Tetracycline resistance and aminoglycoside resistance were the predominant antibiotic resistance gene (ARG) classes found, regardless of the treatment. PFA application resulted in a decrease in abundance of ARGs compared to those in the control group and other antibiotic treatment groups. In summary, the findings from this study demonstrate the potential of phytogenic feed additives could be an alternative to antibiotics in poultry farming, with the added benefit of counteracting antimicrobial resistance development.

Microbiota and Transcriptomic Effects of an Essential Oil Blend and Its Delivery Route Compared to an Antibiotic Growth Promoter in Broiler Chickens

This study evaluated the effect of the delivery of a commercial essential oil blend containing the phytonutrients star anise, cinnamon, rosemary, and thyme oil (via different routes) on broiler chickens’ ileal and ceca microbiota and liver transcriptome compared to an antibiotic growth promoter. Eggs were incubated and allocated into three groups: non-injected, in ovo saline, and in ovo essential oil. On day 18 of incubation, 0.2 mL of essential oil in saline (dilution ratio of 2:1) or saline alone was injected into the amnion. At hatch, chicks were assigned to post-hatch treatment combinations: (A) a negative control (corn-wheat-soybean diet), (B) in-feed antibiotics, (C) in-water essential oil (250 mL/1000 L of drinking water), (D) in ovo saline, (E) in ovo essential oil, and (F) in ovo essential oil plus in-water essential oil in eight replicate cages (six birds/cage) and raised for 28 days. On days 21 and 28, one and two birds per cage were slaughtered, respectively, to collect gut content and liver tissues for further analysis. Alpha and beta diversity differed significantly between ileal and ceca samples but not between treatment groups. In-feed antibiotic treatment significantly increased the proportion of specific bacteria in the family Lachnospiraceae while reducing the proportion of bacteria in the genus Christensenellaceae in the ceca, compared to other treatments. Sex-controlled differential expression of genes related to cell signaling and tight junctions were recorded. This study provides data that could guide the use of these feed additives and a foundation for further research.

Alternatives to antibiotics for organic poultry production: types, modes of action and impacts on bird's health and production

The poultry industry contributes significantly to bridging the nutritional gap in many countries because of its meat and eggs products rich in protein and valuable nutrients at a cost less than other animal meat sources. The natural antibiotics alternatives including probiotics, prebiotics, symbiotics, organic acids, essential oils, enzymes, immunostimulants, and phytogenic (phytobiotic) including herbs, botanicals, essential oils, and oleoresins are the most common feed additives that acquire popularity in poultry industry following the ban of antibiotic growth promoters (AGPs). They are commonly used worldwide because of their unique properties and positive impact on poultry production. They can be easily mixed with other feed ingredients, have no tissue residues, improve feed intake, feed gain, feed conversion rate, improve bird immunity, improve digestion, increase nutrients availability as well as absorbability, have antimicrobial effects, do not affect carcass characters, decrease the usage of antibiotics, acts as antioxidants, anti-inflammatory, compete for stress factors and provide healthy organic products for human consumption. Therefore, the current review focuses on a comprehensive description of different natural antibiotic growth promoters' alternatives, the mode of their action, and their impacts on poultry production.

Essential oils and their nanoemulsions as green alternatives to antibiotics in poultry nutrition: a comprehensive review

Increasing market pressure to reduce the use of antibiotics and the Veterinary Feed Directive of 2019 have led to expanded research on alternate antibiotic solutions. This review aimed to assess the benefits of using essential oils (EOs) and their nanoemulsions (NEs) as feed supplements for poultry and their potential use as antibiotic alternatives in organic poultry production. Antibiotics are commonly used to enhance the growth and prevent diseases in poultry animals due to their antimicrobial activities. EOs are a complex mixture of volatile compounds derived from plants and manufactured via various fermentation, extraction, and steam distillation methods. EOs are categorized into 2 groups of compounds: terpenes and phenylpropenes. Differences among various EOs depend on the source plant type, physical and chemical soil conditions, harvest time, plant maturity, drying technology used, storage conditions, and extraction time. EOs can be used for therapeutic purposes in various situations in broiler production as they possess antibacterial, antifungal, antiparasitic, and antiviral activities. Several studies have been conducted using various combinations of EOs or crude extracts of their bioactive compounds to investigate their complexity and applications in organic poultry production. NEs are carrier systems that can be used to overcome the volatile nature of EOs, which is a major factor limiting their application. NEs are being progressively used to improve the bioavailability of the volatile lipophilic components of EOs. This review discusses the use of these nonantibiotic alternatives as antibiotics for poultry feed in organic poultry production.

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.

Essential Oil Delivery Route: Effect on Broiler Chicken's Growth Performance, Blood Biochemistry, Intestinal Morphology, Immune, and Antioxidant Status

Simple Summary

Much research is devoted to the search for potent alternatives to antibiotic growth promoters in the poultry industry. It is hypothesized that the efficacy of potential alternatives could be influenced by their type and the delivery strategy utilized. Consequently, this study evaluated the efficacy of a commercial essential oil blend across different delivery routes as a potent alternative to in-feed antibiotics in broiler chickens using selected biochemical, immune, and performance parameters. The results provide evidence that the successive delivery of essential oils via in ovo and in-water routes in broiler chickens offers the potential to improve broiler chicken biochemical and antioxidant status. However, the in ovo delivery of essential oil at 0.2 mL dosage (saline + essential oil, dilution ratio—2:1) suffers the limitations of reduced hatchability.

Abstract

This study evaluated the effect of an essential oil blend and its delivery routes on broiler chicken growth performance, blood biochemistry, intestinal morphology, and immune and antioxidant status. Eggs were incubated and allotted to 3 groups: non-injected group, in ovo saline group, and in ovo essential oil group. On day 18 of incubation, essential oil in saline or saline alone was injected into the amnion. At hatch, chicks were assigned to post-hatch treatment combinations (1) in ovo essential oil + in-water essential oil (in ovo + in-water EO); (2) in ovo essential oil (in ovo EO); (3) in ovo saline; (4) in-water essential oil; (5) in-feed antibiotics (Bacitracin methylene disalicylate) and (6) a negative control (NC; corn-wheat-soybean diet) in 8 replicate cages (6 birds/cage) and raised for 28 day. The in ovo EO group reduced (p < 0.05) chick length and hatchability, all groups recorded no difference in growth performance at 0–28 day. The in ovo + in-water EO treatment reduced (p < 0.05) blood creatine kinase and aspartate aminotransferase levels whilst increasing (p < 0.05) total antioxidant capacity in birds. The in ovo + in-water delivery of EO might represent a potential antibiotic reduction strategy for the poultry industry but more research is needed to address the concern of reduced hatchability.

Influence of Trans-anethole on the nutrient digestibility and intestinal barrier function in broilers

This experiment was undertaken to investigate the effects of dietary trans-anethole (TA) at 5 levels (0, 200, 400, 600, and 800 mg/kg of diet) on the growth performance, apparent nutrient digestibility and intestinal barrier function in broilers. Three hundred twenty 1-day-old Arbor Acres broilers were randomly divided into the 5 dietary treatments with 8 replicates each for 42 d. Dietary TA supplementation increased (P < 0.05) average daily feed intake (ADFI), but had no effects (P > 0.05) on average daily gain (ADG), feed/gain (F/G), and body weight (BW) of broilers throughout the entire experimental period. The apparent metabolizable energy (AME) and nitrogen-corrected apparent metabolizable energy (AMEn), the apparent total tract digestibility of dry matter (DM), crude protein (CP), organic matter (OM), and gross energy (GE) showed a quadratic increase (P < 0.05) with the increasing TA concentration in the diet. The apparent ileal digestibility of Lys, Met, Leu, Thr, Ala, Tyr, and Pro were higher (P < 0.05) in birds fed TA diets compared with control group. Dietary supplementation of 400 mg/kg of TA increased (P < 0.05) mRNA levels of jejunal and ileal Na+/glucose co-transporter (SGLT1) on d 21 and d 42, oligopeptide transporter 1 (PepT1) on d 42, and ileal mRNA expressions of occludin (OCLN), claudin-1 (CLDN-1), and mucin 2 (MUC2), villus height (VH), crypt depth (CD), and VH:CD on d 21, as well as jejunal zonula-occludens-1 (ZO-1) and ileal mucin 2 on d 42. Linear or quadratic responses of the jejunal CD and villus VH:CD ratio occurred (P < 0.01) with increasing dietary TA concentration on d 42. The inclusion of 400 mg/kg TA decreased (P < 0.05) cecal Escherichia coli population on d 21 and d 42, but increased (P < 0.05) Bifidobacterium population on d 21 and ileal Bifidobacterium on d 42. In conclusion, 400 mg/kg of TA is the optimum concentration for increasing nutrient utilization and intestinal barrier function of broilers.

Effects of trans-anethole supplementation on serum lipid metabolism parameters, carcass characteristics, meat quality, fatty acid, and amino acid profiles of breast muscle in broiler chickens

This study investigated the effects of trans-anethole (TA) supplementation on the carcass characteristics, meat quality, fatty acid, and amino acid profiles of breast muscle in broilers. A total of 40 one-day-old male broiler chicks (Arbor Acres) were randomly allocated to 5 treatments, respectively, fed a corn-soybean basal diet supplemented with 0 (control), 200, 400, 600, and 800 mg TA/kg diet for 42 d. 600 mg/kg of TA supplementation decreased (P < 0.05) serum triglycerides (TG) on d 21 and d 42, and high density lipoprotein cholesterol (HDL-C) concentration on d 21, but increased (P < 0.01) serum HDL-C concentration on d 42. Dietary supplementation of TA increased (P < 0.01) the half chamber rate (HCR) and eviscerated rate (ER) of broilers. The drip loss (storing 24 and 48 h) and cooking loss of breast muscle in 600 mg/kg TA groups were lower (P < 0.05) than those in control group. The concentration of palmitoleic acid, daturic acid, oleic acid, linoleic acid, α-Linolenic acid, eicostrienoic acid, and pentosapentanoic acid (EPA), MUFA, and PUFA in the breast muscle were higher (P < 0.05) in the 600 mg/kg of TA group compared with other groups. Dietary inclusion of 600 mg/kg of TA also increased (P < 0.05) the concentration of Met, Thr, Asp, Ser, and Glu in breast muscle, tended to increase (P = 0.069) the Lys concentration. In conclusion, results indicated that TA inclusion improved the lipid metabolism, meat quality, fatty acid composition, and amino acid profile of breast muscle in broilers.

Dietary encapsulated essential oil mixture influence on apparent nutrient digestibility, serum metabolic profile, lymphocyte histochemistry and intestinal morphology of laying hens

Objective

The study aimed to evaluate the effects of a mixture of encapsulated essential oils (EOs) addition on nutrient digestion, serum biochemical parameters, peripheral blood alpha-naphthyl acetate esterase (ANAE), and acid phosphatase (ACP-ase) positive lymphocyte ratios and intestinal morphology in laying hens.

Methods

A total of 320 laying hens of 48-wk-old were randomly allotted into 4 treatment groups with 10 replicates of 8 birds in each replicate. The birds were fed a basal diet (control) or the diet added with mixture of EOs (which consist of eugenol, nerolidol, piperine, thymol, linalool, and geraniol) at 50, 100, and 200 mg/kg for period of 84 days.

Results

The addition of EOs at 100 or 200 mg/kg increased the dry matter, organic matter, and crude protein digestion as compared to control. The addition of all doses of EOs did not affect serum gamma glutamyl transferase, alanine aminotransferase, and P but increased serum asparate aminotransferase (AST) concentration. The addition of 200 mg/kg EOs increased serum creatinine, while 100 mg/kg decreased Ca concentration. The addition of 100 and 200 mg/kg EOs generally improved ANAE and ACP-ase positive peripheral blood lymphocyte ratios and intestinal morphology.

Conclusion

It can be concluded that, the addition of 100 or 200 mg/kg encapsulated EOs generally increased apparent nutrient digestion and serum AST concentration, improved ANAE and ACP-ase positive peripheral blood lymphocytes and intestinal morphology in laying hens.

Cinnamon: A Natural Feed Additive for Poultry Health and Production-A Review

The increased bacterial resistance to synthetic antibiotics and consumer awareness about the health and food safety concerns have triggered the ban on the use of antibiotic growth promotors (AGPs) in the poultry industry. This situation encouraged the poultry sector and industry to explore safe alternatives to AGPs and focus on developing more sustainable feed management strategies to improve the intestinal health and growth performance of poultry. Consequently, phytogenic feed additives (PFAs) have emerged as natural alternatives to AGPs and have great potential in the poultry industry. In recent years, cinnamon (one of the most widely used spices) has attracted attention from researchers as a natural product with numerous health benefits for poultry. The essential oils in cinnamon, in particular, are of interest because of their antioxidant, anti-microbial, anti-inflammatory, antifungal, and hypocholesterolaemic effects, in addition to their ability to stimulate digestive enzymes in the gut. This review mainly emphasizes the potential impact of cinnamon as a natural feed additive on overall gut health, nutrient digestibility, blood biochemical profile, gene expression, gut microbiota and immune response.

Effects of essential oil on growth performance, digestibility, immunity, and intestinal health in broilers

Essential oils (EO) are concentrated hydrophobic liquids containing volatile aromatic compounds obtained from plants, which have properties as withdrawn antibiotic growth promoters. The objective of this study was to explore the effects of EO on growth performance, digestibility, immunity and intestinal health in broilers. A total of 500 1-day-old Arbor Acre broilers were randomly put into five groups with 10 replicate cages containing 10 birds each. Birds in the 5 groups were fed a basal diet (CON), and basal diet with 50, 100, 200 or 400 mg/kg EO (EO0.5, EO1, EO2 and EO4) for 42 d respectively. Birds were euthanized at 21d and 42 d, blood and tissue samples were collected. In the study, the digestibility of DM, GE and EE in groups with EO supplementation were significantly increased compared with CON group (P < 0.05). However, only EO2 and EO4 significantly increased the digestibility of CP compared with CON group (P < 0.05). In contrast to CON group, EO0.5 and EO1 in jejunum at 21 d, and EO1 in jejunum at 42 d markedly increased the activity of sucrase (P < 0.05). In addition, the level of SOD of EO2 and EO4 in serum at 21 d was significantly increased compared with CON group (P < 0.05). What's more, the concentration of intestinal mucosa SIgA in jejunum and ileum at 21 d of groups with EO supplementation was significantly increased compared with CON group (P < 0.05). Moreover, V/C in jejunum at 21 d of groups with EO supplementation, CD in jejunum at 42 d was also significantly increased to compare with CON group (P < 0.05). Furthermore, the expression levels of critical genes associated with nutrient transportation (i.e., GLUT2, SGLT1, SLC38A, SLC79A and SLC27A4) and barrier function (TJP1) were quadratically and linearly up-regulated in jejunum and ileum with EO supplementation (P < 0.05). These results suggest that EO has a positive impact on growth, immunity and intestinal health in broilers, and 200 mg/kg of EO was recommended in broiler diet.

Phenolic compounds as natural feed additives in poultry and swine diets: a review

Due to ban on using antibiotics in feed industry, awareness of using natural feed additives have led to a great demand. The interest of plants phenolic compounds as a potential natural antioxidant source has been considered in research community due to their predictable potential role as feed additives in poultry and swine production. However, the mode of action for their functional role and dosage recommendation in animal diets are still remain indistinct. Taking into account, the present review study highlights an outline about the mode of action of phenolic compound and their experimental uses in poultry and swine focusing on the growth performance, antioxidant function, immune function, antimicrobial role and overall health status, justified with the past findings till to date. Finally, the present review study concluded that supplementation of phenolic compounds as natural feed additives may have a role on the antioxidant, immunity, antimicrobial and overall production performance in poultry and swine.

Dietary effects of Garcinia kola seed meal on growth performance, hematology and serum biochemical parameters of weaned rabbits

Background and Aim:

Garcinia kola seed (GKS) is used to prevent and cure a number of gastric-related ailments. GKS contain a copious amount of polyphenols and can be utilized as a natural growth promoter in the nutrition of weaned rabbits. This study aimed to determine the dietary effects of GKS meal (GKSM) on the growth performance, hematology and serum biochemical parameters of weaned rabbits.

Materials and Methods:

GKS were dried and ground into powder. Thirty-two 8-week-old crossbred rabbits with an average weight of 614 g were randomly divided into four dietary groups. The diets were designated as follows: Control (corn-soybean based diet with 0% GKSM) and the GKSM-supplemented diets with 1.5% GKSM, 3% GKSM, and 4.5% GKSM. On the 56^th day of the feeding trial, blood was collected from the marginal ear vein of all rabbits and transferred into two separate labeled tubes. The first set of blood was used to determine the hematological indices. The second set of blood was transferred into plain bottles and allowed to coagulate. The coagulated blood was subjected to standard methods of serum separation, and the sera were harvested and used to evaluate serum biochemical parameters.

Results:

Although the average final body weight was highest in rabbits fed with 1.5% GKSM; this value was similar to rabbits fed with 0% and 4.5% GKSM. The average daily weight gain was highest in rabbits fed with 1.5% GKSM, while the feed conversion ratio was improved in the 0% and 1.5% GKSM groups. The dietary treatments also had a significant effect on the red blood cell count (RBC) and hemoglobin (Hb) concentration, while other blood parameters did not differ significantly (p > 0.05). Higher inclusion levels (3% and 4.5%) of GKSM led to a significant increase in RBC and Hb values (p < 0.05). The total protein increased at all levels of GKSM inclusion (p < 0.05). Bilirubin, sodium, and potassium levels significantly decreased at 4.5% GKSM inclusion (p < 0.05). Urea levels were lowered at 1.5% and 4.5% GKSM inclusion, while cholesterol levels were decreased at 3% and 4.5% dietary levels.

Conclusion:

From the results of the present study, the supplementation of up to 4.5% GKSM revealed no harmful effect on the hematological and serum biochemical parameters of weaned rabbits, while their growth performance improved at a 1.5% inclusion level of GKSM.

Effect of a Phytogenic Feed Additive on Growth Performance, Nutrient Digestion, and Immune Response in Broiler-Fed Diets with Two Different Levels of Crude Protein

Simple Summary

The rising concerns on antibiotics resistance from using antibiotics in animal production has resulted in an increase in researches on antibiotic alternatives. A phytogenic feed additive from a blend of extracts of oregano, cinnamon, citrus peel, and fructooligosaccharides was evaluated in the present study. The objective of the present study is not only to evaluate the effect of phytogenic feed additive on broiler performance, but also to explore the potential mode of actions through immune response, digestive enzyme activities, nutrient transporter gene expressions and nutrient digestibility. Supplementation of phytogenic feed additives improved broiler FCR through stimulating ileum immunity.

Abstract

The aim of this experiment was to evaluate the effect of a phytogenic feed additive (PFA) on growth performance and nutrient digestibility of broilers fed corn and soybean meal-based diets containing two different levels of crude protein. A 2 × 2 completely randomized factorial arrangement (eight replicates/treatment, 30 birds/replicate) was conducted with a positive control (PC) and negative control (NC) containing crude protein at standard or reduced by 1.5% (equivalent to a reduction of 15 g/kg), respectively, and supplementation of PFA at 0 or 125 ppm of diet. There were no significant interactions found between PFA and CP levels in the current study. Main effect analysis showed that during 0–42 d of age NC diets decreased body weight gain (p < 0.05), but increased feed intake (p < 0.05) and feed conversion ratio (FCR, p < 0.01), whereas supplementation of PFA resulted in a lower FCR (p < 0.01). The ileal nutrient digestibility was reduced (p < 0.05) in the broilers fed a reduced protein diet at 21 d compared to the standard protein level group, but there were no effects for PFA levels. Similarly, supplementing PFAs showed no effects on digestive enzyme (Alkaline phosphatase, amylase, and lipase) activity in jejunal digesta and jejunal brush border enzyme (maltase, sucrase, and aminopeptidase) activity. Supplementation of PFA downregulated (p < 0.05) the mRNA expressions of cytochrome P450 1A and interleukin 6 in the ileum but had no effects on nutrient transporter genes in the jejunum. In conclusion, supplementation of PFA reduced broiler FCR during the whole grow-out period and positively regulated the immune responses in the ileum.

Effects of Diet and Phytogenic Inclusion on the Antioxidant Capacity of the Broiler Chicken Gut

Simple Summary

Triggering of poultry capacity to resist challenge stressors could be vital for animal performance and health. Diet may serve as a tool for modulating animal response to oxidative stress. Within the context of a balanced diet, certain feed additives of plant origin, such as phytogenics, may confer additional cytoprotective effects. As gut health is a prerequisite for animal performance, this work delved into advancing our knowledge on dietary and phytogenic effects on the capacity of the poultry gut to counteract oxidative stress. Study findings showed that a reduction in dietary energy and protein intake by 5% primed important antioxidant responses especially upon phytogenic addition. The new knowledge could assist in devising nutritional management strategies for counteracting oxidative stress.

Abstract

The reduction in energy and protein dietary levels, whilst preserving the gut health of broilers, is warranted in modern poultry production. Phytogenic feed additives (PFAs) are purported to enhance performance and antioxidant capacity in broilers. However, few studies have assessed PFA effects on a molecular level related to antioxidant response. The aim of this study was to investigate the effects of administering two dietary types differing in energy and protein levels (L: 95% and H: 100% of hybrid optimal recommendations) supplemented with or without PFA (−, +) on gene expressions relevant for antioxidant response along the broiler gut. Interactions of diet type with PFA (i.e., treatments L−, L+, H−, H+) were determined for critical antioxidant and cyto-protective genes (i.e., nuclear factor erythroid 2-like 2 (Nrf2) pathway) and for the total antioxidant capacity (TAC) in the proximal gut. In particular, the overall antioxidant response along the broiler gut was increased upon reduced dietary energy and protein intake (diet type L) and consistently up-regulated by PFA addition. The study results provide a new mechanistic insight of diet and PFA functions with respect to the overall broiler gut antioxidant capacity.

Priming of intestinal cytoprotective genes and antioxidant capacity by dietary phytogenic inclusion in broilers

The potential of a phytogenic premix (PP) based on ginger, lemon balm, oregano and thyme to stimulate the expression of cytoprotective genes at the broiler gut level was evaluated in this study. In particular, the effects of PP inclusion levels on a selection of genes related to host protection against oxidation (catalase [CAT], superoxide dismutase 1 [SOD1], glutathione peroxidase 2 [GPX2], heme oxygenase 1 [HMOX1], NAD(P)H quinone dehydrogenase 1 [NQO1], nuclear factor (erythroid-derived 2)-like 2 [Nrf2] and kelch like ECH associated protein 1 [Keap1]), stress (heat shock 70 kDa protein 2 [HSP70] and heat shock protein 90 alpha family class A member 1 [HSP90]) and inflammation (nuclear factor kappa B subunit 1 [NF-κB1], Toll-like receptor 2 family member B (TLR2B) and Toll-like receptor 4 [TLR4]) were profiled along the broiler intestine. In addition, broiler intestinal segments were assayed for their total antioxidant capacity (TAC). Depending on PP inclusion level (i.e. 0, 750, 1,000 and 2,000 mg/kg diet) in the basal diets, 1-d-old Cobb broiler chickens (n = 500) were assigned into the following 4 treatments: CON, PP-750, PP-1000 and PP-2000. Each treatment had 5 replicates of 25 chickens with ad libitum access to feed and water. Data were analyzed by ANOVA and means compared using Tukey's honest significant difference (HSD) test. Polynomial contrasts tested the linear and quadratic effect of PP inclusion levels. Inclusion of PP increased (P ≤ 0.05) the expression of cytoprotective genes against oxidation, except CAT. In particular, the cytoprotective against oxidation genes were up-regulated primarily in the duodenum and the ceca and secondarily in the jejunum. Most of the genes were up-regulated in a quadratic manner with increasing PP inclusion level with the highest expression levels noted in treatments PP-750 and PP-1000 compared to CON. Similarly, intestinal TAC was higher in PP-1000 in the duodenum (P = 0.011) and the ceca (P = 0.050) compared to CON. Finally, increasing PP inclusion level resulted in linearly reduced (P ≤ 0.05) expression of NF-κB1, TLR4 and HSP70, the former in the duodenum and the latter 2 in the ceca. Overall, PP inclusion consistently up-regulated cytoprotective genes and down-regulated stress and inflammation related ones. The effect is dependent on PP inclusion level and the intestinal site. The potential of PP to beneficially prime bird cytoprotective responses merit further investigation under stress-challenge conditions.

Consequences of various housing systems and dietary supplementation of thymol, carvacrol, and euganol on performance, egg quality, blood chemistry, and antioxidant parameters

The present work was carried out to investigate the influences of housing system and dietary essential oils (EOs) supplementation to laying hens on the productive performance, egg quality, immunity, antioxidant parameters, and hematology. A factorial arrangement (2 × 4) was performed, including 2 housing systems and 4 different types of EOs (without EOs, thymol, carvacrol, and euganol) during the production stages (from 28–78 wk of age). Birds were randomly divided into 2 groups with each of 2,000 birds. The first group was moved to laying cages while the second group was a floor reared. Each group was randomly divided into 4 groups (5 replicates of 100 birds each): The first were considered as a control group, and the second, third, and fourth groups were treated with thymol, carvacrol, and euganol EO, respectively. The results showed that hens reared in cage system had higher egg weight (P < 0.05), egg production, egg mass, and feed intake and better feed conversion ratio (P < 0.001) than those reared in the floor system. Blood picture values (except white blood cells), phagocytic index, phagocytic activity, and blood chemistry parameters (except calcium, phosphorus, and urea values) of laying hens were not affected (P > 0.05) by housing system. The groups fed EOs showed a rapid improvement (P < 0.001) in the egg production%, egg weight, egg mass, and egg quality. Thymol group had the highest egg production (P < 0.001). Thymol and eugenol groups had the highest egg weight, egg mass, and egg quality (P < 0.001). The groups fed diets containing thymol or eugenol consumed lower feed and had better feed conversion ratio (P < 0.001) than the control group. Immunity indices (phagocytic activity [P < 0.05], avian influenza [AIH5 and AIH9], P < 0.001) were improved with the presence of EOs in the laying hen diet. These results strongly suggest that dietary EO supplementation could be a successful attempt to improve the productive performance, egg quality, and immunity of laying hens.

V, Izquierdo M, Terova G. Assessment of dietary supplementation with galactomannan oligosaccharides and phytogenics on gut microbiota of European sea bass (Dicentrarchus Labrax) fed low fishmeal and fish oil based diet

There is an increasing interest from the aquafeed industry in functional feeds containing selected additives that improve fish growth performance and health status. Functional feed additives include probiotics, prebiotics, organic acids, and phytogenics (substances derived from plants and their extracts). This study evaluated the effects of dietary inclusion of a mucilage extract rich in galactomannan oligosaccharides (GMOS), a mixture of garlic and labiatae-plants oils (PHYTO), and a combination of them (GMOSPHYTO), on gut microbiota composition of European sea bass (Dicentrarchus labrax) fed with a low fishmeal (FM) and fish oil (FO) diet. Three experimental diets and a control diet (plant-based formulation with 10% FM and 6% FO) were tested in a 63-days feeding trial. To analyze the microbiota associated to feeds and the intestinal autochthonous (mucosa-adhered) and allochthonous (transient) microbial communities, the Illumina MiSeq platform for sequencing of 16S rRNA gene and QIIME2 pipeline were used. Metabarcoding analysis of feed-associated bacteria showed that the microbial communities of control (CTRL) feed deeply differed from those of experimental diets. The number of reads was significantly lower in CTRL feed than in other feeds. The OTU (operational taxonomic unit) number was instead similar between the feeds, ranging from 42 to 50 OTUs. The variation of resident gut microbiota induced by diet was lower than the variation of transient intestinal microbiota, because feedstuffs are a major source of allochthonous bacteria, which can temporarily integrate into the gut transient microbiome. However, the composition of transient bacterial communities was not simply a mirror of feed-borne bacteria. Indeed, the microbial profile of feeds was different from both faecal and mucosa profiles. Our findings suggest that the dietary inclusion of GMOS (0.5%) and PHYTO (0.02%) in a low FM and FO diet induces changes in gut microbiota composition of European sea bass. However, if on allochthonous microbiota the combined inclusion of GMOS and PHYTO showed an antagonistic effect on bactericidal activity against Vibrionales, at mucosa level, only GMOSPHYTO diet increased the relative abundance of Bacteroidales, Lactobacillales, and Clostridiales resident bacterial orders. The main beneficial effects of GMOS and PHYTO on gut microbiota are the reduction of coliforms and Vibrionales bacteria, which include several potentially pathogenic species for fish, and the enrichment of gut microbiota composition with butyrate producer taxa. Therefore, these functional ingredients have a great potential to be used as health-promoting agents in the farming of European sea bass and other marine fish.

Effects of phytogenic inclusion level on broiler carcass yield, meat antioxidant capacity, availability of dietary energy, and expression of intestinal genes relevant for nutrient absorptive and cell growth–protein synthesis metabolic functions

Context Phytogenic applications in animal nutrition currently attract worldwide scientific attention for their potential to contribute positively to sustainable and high-quality animal production. However, further understanding and substantiation of dietary phytogenic functions is required. Aims The inclusion level of a phytogenic premix (PP) comprising functional flavouring substances from ginger, lemon balm, oregano and thyme was studied for its effects on broiler growth performance, carcass traits, nutrient digestibility, liver and meat total antioxidant capacity (TAC), and lipid oxidation. The expression of genes for nutrient transporter proteins (SGLT1, GLUT2, PEPT1, BOAT and LAT1), for FABP2 involved in cellular fatty acid uptake and metabolism, and for the mTORC1 complex relevant for protein synthesis were profiled along the intestine. Methods One-day-old Cobb broiler chickens (n = 500) were assigned to four treatments with five replicates of 25 chickens each. Starter (1–10 days), grower (11–22 days) and finisher (23–42 days) basal diets were supplemented with four levels of PP inclusion as treatments: 0, 750, 1000 and 2000 mg/kg diet, termed control, PP750, PP1000 and PP2000. Feed and water were available ad libitum. Data were analysed by ANOVA, taking the treatment as fixed effect. Statistically significant (P ≤ 0.05) effects were further analysed and means were compared using Tukey’s HSD test. Polynomial contrasts tested the linear and quadratic effect of PP inclusion levels. Key results Growth performance responses were not improved significantly (P &gt; 0.05) by PP inclusion level. However, carcass (P = 0.030) and breast meat yield (P = 0.023) were higher in PP1000 than in the control. In addition, PP1000 had higher (P = 0.049) apparent metabolisable energy than PP2000 and the control. Increasing PP inclusion level increased breast (P = 0.005), thigh (P = 0.002) and liver (P = 0.040) TAC. Breast and thigh meat TAC reached a plateau at PP1000, whereas liver TAC continued to increase linearly. Lipid oxidation in breast meat and liver was delayed linearly (P ≤ 0.05) with increasing PP inclusion level. Expression of genes SGLT1, GLUT2, PEPT1, BOAT and FABP2 were not affected by PP inclusion. However, PP inclusion affected the expression of LAT1 (P &lt; 0.001) in jejunum and of mTORC1 in duodenum (P = 0.010) and ceca (P = 0.025). In particular, expression increased with increasing PP inclusion level in a linear and quadratic pattern depending on the intestinal segment. Conclusions Overall, PP inclusion at 1000 mg/kg diet improved carcass and breast yield, dietary available energy, and overall meat and liver TAC. Preliminary evidence was highlighted for effects of PP in promoting expression of genes relevant for muscle protein synthesis. Implications This study has contributed new information on effects of a phytogenic premix on broiler meat yield and antioxidant capacity, digestibility, absorption and metabolic functions, further supporting phytogenic benefits for broiler production.

Effect of dietary supplementation with phytogenic blend on growth performance, apparent ileal digestibility of nutrients, intestinal morphology, and cecal microflora of broiler chickens

The effects of dietary supplementation with phytogenic blend (PB) of Aerva lanata, Piper betle, Cynodon dactylon, and Piper nigrum on growth performance, ileal nutrient digestibility, intestinal morphology, and cecal microflora were determined in a 42-day broiler feeding trial. A total of 192 broilers were assigned to 4 dietary treatments (6 replicates and 8 birds/replicate): basal diet, basal diet supplemented with antibiotic (chlortetracycline), 1% and 2% PB, respectively. The body weight gain (BWG) of starter chicks increased linearly (P = 0.023) as dietary supplementation levels of PB increased. At grower phase, broilers fed diet supplemented with 1% PB had similar BWG with the antibiotic group, but other treatments had reduced (P = 0.0001) BWG. Dietary supplementation with 1% PB resulted in the highest (P < 0.0001) BWG during the study. Feed intake was not affected by the treatments during the starter, finisher, and overall rearing periods. Broilers fed diet supplemented with 1% PB had the best (P < 0.0001) feed conversion ratio during the study. Overall, broilers fed only basal diet had the highest (P = 0.0450) mortality. Ileal organic matter (OM) digestibility increased linearly (P = 0.044) with broilers fed diet supplemented with PB, but reduced with antibiotic group. Dietary supplementation with 1% PB had the highest (P = 0.0402) ileal digestibility of tryptophan. In the duodenum, broilers fed diet supplemented with PB had longer (P = 0.0006) villi heights than the birds fed only basal diet, but similar with antibiotic group. Broilers fed diet supplemented with PB had longer (P = 0.0064) villi height in the jejunum than the antibiotic group. Bifidobacterium concentration of the cecum content showed a slight increase (P = 0.053) with increasing supplementation levels of PB. In conclusion, the current study shows that dietary supplementation with PB improves growth performance, intestinal morphology, and apparent ileal digestibility of OM and tryptophan in a dose-dependent manner with the best response at 1% inclusion level.

Impacts of Strain Variation on Response to Heat Stress and Boldo Extract Supplementation to Broiler Chickens

Simple Summary

One of the common approaches to alleviating heat-stress in poultry is nutritional manipulation using herbal extracts or their derivatives to maintain the health, welfare, and performance of birds. The present study investigated the protective effect of boldo leaf extract against the harmful effects of cyclic heat stress in two broiler strains (Arbor Acres; AA and Avian-48; AV). Administration of boldo in drinking water was able to restore growth and health traits to nearly normal values. Generally, AA chicks were better able to withstand heat stress and were also more likely to utilize boldo extract than AV chicks. The use of boldo leaf extract in poultry production can assist in mitigating the effect of heat stress, improving the antioxidant defense system, and increasing productivity and profitability.

Abstract

There is increasing interest in the use of natural antioxidant supplements in poultry diets as protection against the adverse effects of heat stress. The potential protective effect of boldo (Peumus boldus molina) leaf extract, which have antioxidant activity, were investigated against the harmful effects of heat stress in two broiler strains. Arbor Acres (AA) and Avian-48 (AV) chicks were divided into thermoneutral (TN) and heat stress (HS) groups and treated with 1 g boldo leaf extract/4 L drinking water during the heat stress period. HS reduced growth performance in both strains. The phagocytic index, phagocytic activity, and eosinophil and lymphocytes counts were significantly elevated in TN and HS AV birds but not altered in AA birds. Boldo extract treatment partially eliminated the previous negative impacts of heat stress. AA chicks were better able to withstand HS than AV chicks. Serum concentrations of total lipids and cholesterol were reduced in HS birds of both strains. Malondialdehyde, superoxide dismutase, and glutathione peroxidase levels were elevated but restored with the administration of boldo leaf extract in HS birds of both strains. Economic parameters were negatively affected by HS but restored to values close to those of the control group in boldo-treated HS birds. In conclusion, the administration of boldo leaf extract in drinking water was effective in neutralizing the harmful effects of heat stress on growth performance, blood indices, and economic parameters and improved the antioxidant defense system in heat-stressed birds.

Immune modulation, growth performance, and nutrient retention in broiler chickens fed a blend of phytogenic feed additives

This study aimed to assess the effect of a commercial blend of phytogenic feed additives (PA), comprising 5% carvacrol, 3% cinnamaldehyde, and 2% capsicum oleoresin on the modulation of immune biomarkers of broiler chickens, their growth performance, dietary energy, and nutrient retention. Four-hundred day-old birds were assigned to one of four dietary treatments. Two control diets based on either wheat (WC) or maize (MC) were each given with and without PA at 100 g/t. Growth performance variables including feed intake (FI), weight gain (WG), and feed conversion ratio (FCR) were recorded. Dietary N-corrected apparent metabolizable energy (MEn), dry matter (DMR), nitrogen (NR), and fat retention (FR) coefficients were also determined. Gene expression of immune biomarkers (cytokines) were determined in caecal tonsil tissue from 21 d old birds. Expression of IL2, IL18, IL10, and IL17C in the caecal tonsils were upregulated (P < 0.05) in the birds fed MC-based diets compared to the WC fed birds. Feeding PA supplemented diets downregulated the expression of CD40LG (P < 0.001), IFNG, and IL6 (P < 0.05). There was a cereal type × PA interaction (P < 0.05), as expression of IFNB was downregulated in the birds fed PA supplemented MC but not WC. However, expression of IL12B was downregulated in birds fed PA supplemented WC but there was no significant (P > 0.05) change in expression levels in birds fed MC diets. Feeding MC diets gave greater FI (P < 0.001) and ME (P < 0.05), but lower FCR (P < 0.05) compared to birds fed WC diets. The WG and nutrient retention coefficients were not affected (P > 0.05) by cereal type. Supplementary PA improved FI (P < 0.05), WG (P < 0.001), FCR (P < 0.05), MEn (P < 0.05), MEn: GE ratio (P < 0.05), and FR (P < 0.05). In conclusion, dietary inclusion of PA improved overall growth performance variables, energy, and nutrient retention and intestinal cytokine expression.

Influence of the particle size and form of feed on growth performance, digestive tract traits and nutrient digestibility of white egg-laying pullets from 1 to 112 D of age

The influence of the grinding and physical form of diets on growth performance, gastrointestinal tract (GIT) development and nutrient digestibility was studied in layer pullets from hatch to 112 d of age. Diet formed a 2 × 2 factorial with 2 hammer mill screen sizes to grind cereals (4 and 8 mm) and 2 forms (mash and crumble). A total of 864 1-day-old layer chickens were randomly assigned to 1 of the 4 treatment groups with 8 replicates (27 birds per replicate). Cumulatively, pullets fed crumbles consumed less feed (P < 0.05) and had better feed conversion ratio (FCR; P < 0.01) than those fed mash. Coarse grinding cereals (CG) improved FCR (P < 0.05) without significant change in cumulative feed consumption compared to that of fine grinding (FG). With regard to body weight gain (BWG), pullets benefited from crumbles from 1 to 56 d of age (P < 0.01). There were interactions (P < 0.05) between screen size and feed form in relation to FCR (1 to 28 d) and overall BWG. At 112 d of age, the relative weight (RW, g/100 g body weight) of the crop, gizzard, pancreas, and liver of crumble-fed birds were lower (P < 0.05) than those for birds fed mash. Pullets fed coarsely ground feed had higher RW of the crop, proventriculus, gizzard, liver, and caecum compared to those fed finely ground feed. Compared to mash feeding, pullets fed crumbles increased (P < 0.05) total tract digestibility of ether extract and crude protein and the activities of pancreatic amylase and lipase. Digestibility of ether extract (P < 0.05) and pancreatic amylase activity (P < 0.01) were higher in birds fed a CG diet than in birds fed the FG regimen. Regarding the nutrition of egg-laying pullets, crumbles might be preferred to mash feed when the main objective is to improve FCR. Data also suggested that cereals used for pullet feed can be ground more coarsely than is in current practice.

Effects of star anise (Illicium verum Hook.f.) essential oil on nutrient and energy utilization of laying hens

An experiment using 96 Hy-Line brown laying hens at 29 weeks of age that were randomly allocated to four treatments with eight replicates was conducted to assess the effects of star anise (Illicium verum Hook.f.) oil (SAO) on nutrient and energy utilization. Dietary treatments were corn-soybean meal-based diets supplemented with 0, 200, 400, and 600 mg/kg SAO. The birds were fed the diets for 14 days. The conventional nutrients and amino acids of feed and excreta samples were measured for calculating apparent metabolic efficiency, and gross energy (GE) was analyzed for computation of apparent metabolic energy (AME) and true metabolic energy (TME). Endogenous losses were obtained from another 16 birds for calculating true metabolic efficiency. Birds supplemented with SAO had higher (p < 0.05) metabolic efficiency of crude protein (CP), organic matter (OM), Lys, Met, Arg, and Thr than those of control group. Quadratic effects on utilization of Lys, Met, and Thr were observed (p < 0.05). Inclusion of SAO to diet improved nutrient utilization, and the efficacy is best at 400 mg/kg.