Formic acid as an antibiotic alternative in broiler diets: effects on growth, carcass characteristics, blood chemistry, and intestinal microbial load

This study explored the ability of formic acid (FA) to replace antibiotics in broiler chicken diets. It examined how FA affected the chickens' growth, carcass characteristics, blood chemistry, and gut bacteria. The experiment randomly assigned 300 one-day-old (Ross 308) broiler chicks to 5 groups, each divided into 6 replicates with 10 unsexed chicks. The following were the treatments: 1st group, negative control (NC): only received a basal diet; 2nd group, positive control (PC): received a basal diet supplemented with 0.5 grams of Colistin antibiotic per kilogram of diet; 3rd, 4th, and 5th groups (FA2, FA4, and FA6) these groups received a basal diet along with formic acid added at increasing levels: 2, 4, and 6 Cm3 per kilogram of diet, respectively. Results found no significant differences in live body weight (LBW) or body weight gain (BWG) between treatment groups, except for LBW at one week and BWG at 0 to 1 and 4 to 5 wk of age. No significant variations were found in feed intake (FI) and feed conversion ratio (FCR) among the treatment groups, excluding FI and FCR at 1 to 2 wk of age. The treatments significantly impacted carcass traits, dressing percentage, breast meat, thigh meat, spleen, giblets, blood levels of urea, creatinine, total protein, globulin, and albumin, as well as the activity of enzymes alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in chicks fed different diets compared to control groups. The addition of FA to the diet significantly impacted antioxidant levels. Also, the FA2 group had the highest total bacterial count (TBC). However, the FA6 group was the opposite; it had the lowest levels of harmful bacteria, such as E. coli and Coliform. Supplementing broiler diets with formic acid improves blood parameters, antioxidant activity, and gut bacteria counts, with 4.0 cm³ formic acid/kg diet supplementation promoting optimal broiler health and product quality.

Dietary supplementation of microencapsulated botanicals and organic acids enhances the expression and function of intestine epithelial digestive enzymes and nutrient transporters in broiler chickens

Organic acids and botanicals have shown protective effects on gut barrier and against inflammation in broilers. However, their effects on intestinal digestive enzymes and nutrients transporters expression and functions have not been fully studied. The objective of this study was to understand how a microencapsulated blend of botanicals and organic acids affected intestinal enzyme activities and nutrient transporters expression and functions in broilers. A total of 288 birds were assigned to a commercial control diet or diet supplemented with 500 g/MT (metric ton) of the microencapsulated additive. Growth performance was recorded weekly. At d 21 and d 42, jejunum and ileum were isolated for enzyme (maltase, sucrase, and aminopeptidase) and transporter (SGLT1, GLUT2, GLUT1, EAAT3, B0AT1, and PepT1) analyses. Jejunum specific nutrients (glucose, alanine, and glutamate) transport activities were evaluated by Ussing chamber. Protein expression of nutrient transporters in small intestine were measured in mucosa and brush-border membrane (BBM) samples by western blot. Intestinal gene expression of the transporters was determined by RT-PCR. Statistical analysis was performed using Student's t-test comparing the supplemented diet to the control. The feed efficiency was significantly improved through the study period in the supplemented group (P ≤ 0.05). Significant changes of intestinal histology were shown in both jejunum (P ≤ 0.10) and ileum (P ≤ 0.05) after 21 d of treatment. At d21, jejunal maltase activity was upregulated (P ≤ 0.10). The Ussing chamber transport of glucose and alanine was increased, which was in line with increased gene expression (GLUT2, GLUT1, EAAT3, and B0AT1) (P ≤ 0.10 and P ≤ 0.05, respectively) and BBMV protein levels (B0AT1, P < 0.10). At d21, ileal sucrase and maltase activities were upregulated (P ≤ 0.05). Increased expressions of GLUT1, EAAT3, and B0AT1 were observed in both mRNA and protein levels (P ≤ 0.05). Similar pattern of changes was also shown at d42 of age. Our results suggest that feeding microencapsulated additives improves intestinal nutrient digestion and transporter expression and function in broilers, thereby enhancing feed efficiency.

Growth performance, carcass characteristics, and blood biochemical indices of broilers affected by dietary organic acids blend's supplementation

The objective of the present study was to explore the influence of organic acids cocktail (lactic-L plus formic-F acid, LF) in broiler diets on feed utilization, growth rate, blood indices and carcass traits. A total of 300 chicks were used and allotted to five treatment groups. The rations contained 0 additives (negative control-NC), basal diet + 0.5 g Colistin® (positive control-PC); LF2, LF4 and LF6: basal diet + 2, 4 and 6 cm3 LF/kg diet, respectively. There were no differences in feed consumption and feed conversion due to LF treatments at all ages except FI at 1-2 wks of age which was significantly affected by gradual levels of LF (p < 0.05). All carcass traits were statistically significant (p < 0.05) differed due to LF treatments. The alterations in urea, creatinine total protein, globulin and albumin in addition to the activity of alanine aminotransferase and aspartate aminotransferase in broiler chicks were significantly different when compared to controls. Malondialdehyde (MDA) slightly decreased with an increase in the level of formic plus lactic. Based on our results, the highest and middle levels (6 and 4 cm3 LF/kg diet) are recommended for the best performance and health aspects of broilers.

In ovo effect of Soursop (Annona muricata L.) leaf extract on hatching and post-hatch performance of Noiler chickens

Pharmacological and nutritional benefits of plant leaf extracts can be harnessed to address the problem of poor chick quality, performance and high mortality, which affect both hatchery and farm managers. This study sought to evaluate the in ovo effect of Soursop leaf extract (SLE) on the hatching and post-hatch performance of Noiler chicks. A total of 640 fertile eggs were randomly distributed into four groups of five replicates: (0.25 µg SLE), (0.5 µg SLE), (0.75 µg SLE) and a non-injected control. On day 18 of incubation, 0.2 ml of SLE was injected into the airspace of the eggs. At hatch, embryonic mortality, hatchability, and chick quality were evaluated. Hatched chicks were reared to assess feed intake, weight gain, feed conversion ratio (FCR) and mortality. Results showed no significant difference (p > 0.05) in embryonic mortality, hatchability and weight gain among the treatment groups. Chick weight and feed intake were significantly higher (p < 0.05) in SLE groups, while FCR and mortality were significantly lower (p < 0.05) in SLE groups. It was concluded that in ovo injection of SLE improved chick weights, feed conversion and livability of Noiler chicks.

Practical Preventive Considerations for Reducing the Public Health Burden of Poultry-Related Salmonellosis

With poultry products as one of the leading reservoirs for the pathogen, in a typical year in the United States, it is estimated that over one million individuals contract non-typhoidal Salmonella infections. Foodborne outbreaks associated with Salmonella infections in poultry, thus, continue to remain a significant risk to public health. Moreover, the further emergence of antimicrobial resistance among various serovars of Salmonella is an additional public health concern. Feeding-based strategies (such as use of prebiotics, probiotics, and/or phytobiotics as well as essential oils), non-feeding-based strategies (such as use of bacteriophages, vaccinations, and in ovo strategies), omics tools and surveillance for identifying antibiotic-resistance genes, post-harvest application of antimicrobials, and biosecurity measures at poultry facilities are practical interventions that could reduce the public health burden of salmonellosis and antibiotic resistance associated with poultry products. With the escalating consumption of poultry products around the globe, the fate, prevalence, and transmission of Salmonella in agricultural settings and various poultry-processing facilities are major public health challenges demanding integrated control measures throughout the food chain. Implementation of practical preventive measures discussed in the current study could appreciably reduce the public health burden of foodborne salmonellosis associated with poultry products.

The effects of essential oil from Lippia origanoides and herbal betaine on performance, intestinal integrity, bone mineralization and meat quality in broiler chickens subjected to cyclic heat stress

Essential oils (EO) affect performance, intestinal integrity, bone mineralization, and meat quality in broiler chickens subjected to cyclic heat stress (HS). Day-of-hatch Cobb 500 male broiler chicks (n = 475) were randomly divided into four groups. Group 1: No heat stress (Thermoneutral) + control diets with no antibiotics; Group 2: heat stress control + control diets; Group 3: heat stress + control diets supplemented with thymol chemotype (45 ppm) and herbal betaine (150 ppm) formulation EO1; Group 4: heat stress + control diets supplemented with phellandrene (45 ppm) and herbal betaine (150 ppm) formulation EO2. From day 10-42, the heat stress groups were exposed to cyclic HS at 35°C for 12 h (8:00-20:00). BW, BWG, FI, and FCRc were measured at d 0, 10, 28, and 42. Chickens were orally gavaged with FITC-d on days 10 (before heat stress) and 42. Morphometric analysis of duodenum and ileum samples and bone mineralization of tibias were done. Meat quality was assessed on day 43 with ten chickens per pen per treatment. Heat stress reduced BW by day 28 (p < 0.05) compared to thermoneutral chickens. At the end of the trial, chickens that received both formulations of EO1 and EO2 had significantly higher BW than HS control chickens. A similar trend was observed for BWG. FCRc was impaired by EO2 supplementation. There was a significant increase in total mortality in EO2 compared with EO1 EO1 chickens had lower FITC-d concentrations at day 42 than the HS control. In addition, EO1 treatment is not statistically different if compared to EO2 and thermoneutral. Control HS broilers had significantly lower tibia breaking strength and total ash at day 42 than heat-stressed chickens supplemented with EO1 and EO2. Heat stress affected intestinal morphology more than thermoneutral chickens. EO1 and EO2 improved intestinal morphology in heat-stressed chickens. Woody breast and white striping were more common in thermoneutral chickens than heat stress chickens. In conclusion, the EO-containing diet could improve broiler chicken growth during cyclic heat stress, becoming increasingly relevant in antibiotic-free production in harsh climates.

Dietary threonine and lysophospholipid supplement in broiler chickens: effect on productive performance, carcass variables, cecal microbiota activity, and jejunal morphology

The objective of this experiment was to investigate the efficacy of lysophospholipid (LPL) in combination with different levels of threonine (Thr) on productive performance, jejunal morphometric variables, cecal microbial population, and carcass characteristics of male broiler chickens. Four hundred 1-day-old male broiler chicks were distributed into eight experimental groups with five replicates, each of ten birds. Factors were two levels of 0 or 0.1% Lipidol as LPL supplement and four inclusion amount of Thr (100, 105, 110, or 115% of requirements) in the diets. During 1 to 35 days, inclusion of LPL supplementation in diets improved the body weight gain (BWG) and feed conversion ratio (FCR) of broilers (P < 0.05). Besides, FCR was significantly greater in the birds fed with 100% Thr compared to the other inclusion rates of Thr (P < 0.05). The jejuna villus length (VL) and crypt depth (CD) were greater in the birds fed with LPL-supplemented diets (P < 0.05) while the greatest VH/CD and villus surface was observed in the birds fed with 105% of dietary Thr (P < 0.05). In cecal microbiota composition, Lactobacillus population was lower in broilers which received diet containing 100% Thr compared to the other group receiving more than 100% Thr (P < 0.05). In conclusion, inclusion of LPL supplements and amounts greater than Thr requirement in diet improved productive performance and jejunal morphology of male broiler chickens.

Effect of citrus-coconut electrolyte blend on growth performance, haemato-biochemical status, organs development and intestinal morphology of broiler chickens

INTRODUCTION

In a bid to mitigate growing concerns regarding the use of antibiotics in food animals OBJECTIVES: This study determined the growth performance, haemato-biochemical status, organ development and intestinal morphology of Arbor Acre broiler chicken strain on oral administration of citrus-coconut electrolyte blend (CCEB) for 26 days.

METHODS

One-hundred ninety-two chicks were brooded for 2 weeks and thereafter divided on a weight equalization basis into four groups (0, 5, 10 and 15 ml CCEB per litre of water) of six replicates each and eight birds per replicate. Phytochemical screening of CCEB was determined, while data collected for growth performance, organ proportions and intestinal morphology were subjected to a one-way analysis of variance.

RESULTS

Phytochemical composition revealed the abundance of phenols (128.40 mg/100g) and tannins (78.10 mg/100g) in CCEB. All productive performance parameters measured were not significantly (p < 0.05) different across treatment means. However, significantly (p < 0.05) highest concentrations (134.47 and 66.48 mg/dl, respectively) for total cholesterol and high-density lipoprotein (HDL) and the lowest concentration (38.34 mg/dl) for low-density lipoprotein (LDL) were recorded in birds on 15 ml of CCEB/litre of water. Furthermore, a progressive reduction (p < 0.05) in the bursa of Fabricius was observed with increasing CCEB/litre of water. The supplementation of CCEB did not influence (p > 0.05) duodenal morphological parameters.

CONCLUSION

The study concluded that 15 ml of CCEB/litre of water enhanced the production of HDL, reduced LDL, and improved immunity via the reduction of the bursa of Fabricius in broiler chickens.

Effect of benzoic acid, Enterococcus faecium, and essential oil complex on intestinal microbiota of laying hens under coccidia and Clostridium perfringens challenge

The objective of this study was to investigate whether dietary supplementation with benzoic acid, Enterococcus faecium, and essential oil complex (BEC) could help laying hens recover from coccidia and Clostridium perfringens type A challenge. A total of 60 (35-wk-old) Lohmann-laying hens were randomly assigned to 3 experimental groups (10 replicates with 2 hens per replicate): I) control group (CON), II) challenge group (CC), and III) BEC group (2,000 mg/kg BEC). The total experimental period was 8 wk. The results shown that the challenge layers had lower egg-laying rate and average daily feed intake (ADFI) (P < 0.05), and addition of BEC after challenge increased egg-laying rate (P < 0.05). The content of propionic acid (PA) and butyric acid (BA) in short-chain fatty acid (SCFA) was significantly decreased by challenge (P < 0.05). CC and BEC groups had lower villus height to crypt depth ratio (V/C) and higher pathological scores in duodenum (P < 0.05), whereas the BEC group had lower pathological scores in jejunum when compared with the CC group (P < 0.05). The challenge increased the concentration of proinflammatory cytokines (IL-1β and IL-6) (P < 0.05). An increase in the abundance of Bacteroidoes (genus), Bacteroidaceae (family), Bacteroidoes sp. Marseille P3166 (species), Bacteroidoes caecicola (species) was observed in the CC group, whereas the BEC group had higher abundance of Bacteroides caecigallinarum (species). The genera Faecalibacterium and Asterolplasma were positively correlated with egg-laying rate (r = 0.57, 0.60; P < 0.01); and the genera Bacteroides and Romboutsia were negatively correlated with egg-laying rate (r = -0.58, -0.74; P < 0.01). The genera Bacteroides, Lactobacillus, and Rombutzia were positively correlated with jejunal mucosa proinflammatory factor IL-1β level (r = 0.61, 0.60, 0.59; P < 0.01), which were negatively correlated with genera Rikenbacteriaceae RC9, Faecalibacterium, and Olsenlla (r = -0.56, -0.57, -0.61; P < 0.01). There genera UCG.005 was positively correlated with proinflammatory factor IL-6 level in jejunal mucosa (r = 0.58; P < 0.01), which was negatively correlated with Rikenbacteriaceae RC9 (r = -0.62; P < 0.01). The experiment results revealed that the addition of BEC to the diet restored the production performance of the laying hens. In addition, supplementation of 2,000 mg/kg BEC modulated gut health by reducing gut damage scores and modulating microbial composition, thereby promoting recovery of laying hens after coccidia and Clostridium perfringens challenge.

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.

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.

Heat stress develops with increased total-tract gut permeability, and dietary organic acid and pure botanical supplementation partly restores lactation performance in Holstein dairy cows

To evaluate the effects of heat stress (HS) conditions and dietary organic acid and pure botanical (OA/PB) supplementation on gut permeability and milk production, we enrolled 46 multiparous Holstein cows [208 ± 4.65 dry matter intake (DMI; mean ± SD), 3.0 ± 0.42 lactation, 122 ± 4.92 d pregnant, and 39.2 ± 0.26 kg of milk yield] in a study with a completely randomized design. Cows were assigned to 1 of 4 groups: thermoneutral conditions (TN-Con, n = 12), HS conditions (HS-Con, n = 12), thermoneutral conditions pair-fed to HS-Con (TN-PF, n = 12), or HS supplemented with OA/PB [75 mg/kg of body weight (BW); 25% citric acid, 16.7% sorbic acid, 1.7% thymol, 1.0% vanillin, and 55.6% triglyceride; HS-OAPB, n = 10]. Supplements were delivered twice daily by top-dress; all cows not supplemented with OA/PB received an equivalent amount of the triglyceride used for microencapsulation of the OA/PB supplement as a top-dress. Cows were maintained in thermoneutrality [temperature-humidity index (THI) = 68] during a 7-d acclimation and covariate period. Thereafter, cows remained in thermoneutral conditions or were moved to HS conditions (THI: diurnal change 74 to 82) for 14 d. Cows were milked twice daily. Clinical assessments and BW were recorded, blood was sampled, and gastrointestinal permeability measurements were repeatedly evaluated. The mixed model included fixed effects of treatment, time, and their interaction. Rectal and skin temperatures and respiration rates were greater in HS-Con and HS-OAPB relative to TN-Con. Dry matter intake, water intake, and yields of energy-corrected milk (ECM), protein, and lactose were lower in HS-Con relative to HS-OAPB. Nitrogen efficiency was improved in HS-OAPB relative to HS-Con. Compared with TN-Con and TN-PF, milk yield and ECM were lower in HS-Con cows. Total-tract gastrointestinal permeability measured at d 3 of treatment was greater in HS-Con relative to TN-Con or TN-PF. Plasma total fatty acid concentrations were reduced, whereas insulin concentrations were increased in HS-Con relative to TN-PF. We conclude that exposure to a heat-stress environment increases total-tract gastrointestinal permeability. This study highlights important mechanisms that might account for milk production losses caused by heat stress, independent of changes in DMI. Our observations also suggest that dietary supplementation of OA/PB is a means to partly restore ECM production and improve nitrogen efficiency in dairy cattle experiencing heat stress.

Growth performance, carcass yield and characteristics, meat quality, serum biochemistry, jejunal histomorphometry, oxidative stability of liver and breast muscle, and immune response of broiler chickens fed natural antioxidant alone or in combination with &lt;i&gt;Bacillus licheniformis&lt;/i&gt;

Abstract. In this study, oxidative stability of liver and breast meat, and immune response were evaluated in broiler chickens fed supplemental phytogenic feed additive (PFA) alone or in combination with Bacillus licheniformis. Three experimental groups – control, PFA (60 mg kg−1), and PFA (60 mg kg−1) + 0.5 mg kg−1 B. licheniformis (1.6 × 1012 cfu g−1), each consisting of 5 replicates – were established with 20 one-day-old chickens per replicate (300 birds in total). Growth performance, carcass yield and characteristics, and meat quality remained unaffected. However, supplemental PFA and PFA + B. licheniformis improved the serum biochemistry and jejunal histomorphometry of broiler chickens (P<0.05). PFA and PFA + B. licheniformis groups had lower thiobarbituric acid reacting substances (TBARS) in liver, and freeze–thaw breast meat after 30, 60, and 90 d of storage (P<0.05). PFA and PFA + B. licheniformis supplementation lowered the carbonyl group in fresh and stored breast meat (P<0.05). Antibody titer against infectious bursal disease virus was higher in the PFA + B. licheniformis group than the control group (P<0.05). It can be concluded that PFA or PFA + B. licheniformis in broiler diets improves the health, oxidative stability of liver and breast meat, and immune response of broiler chickens.

Nanodelivery of essential oils as efficient tools against antimicrobial resistance: a review of the type and physical-chemical properties of the delivery systems and applications

This review provides a synthesis of the last ten years of research on nanodelivery systems used for the delivery of essential oils (EOs), as well as their potential as a viable alternative to antibiotics in human and veterinary therapy. The use of essential oils alone in therapy is not always possible due to several limitations but nanodelivery systems seem to be able to overcome these issues. The choice of the essential oil, as well as the choice of the nanodelivery system influences the therapeutic efficacy obtained. While several studies on the characterization of EOs exist, this review assesses the characteristics of the nanomaterials used for the delivery of essential oils, as well as impact on the functionality of nanodelivered essential oils, and successful applications. Two classes of delivery systems stand out: polymeric nanoparticles (NPs) including chitosan, cellulose, zein, sodium alginate, and poly(lactic-co-glycolic) acid (PLGA), and lipidic NPs including nanostructured lipid carriers, solid lipid NPs, nanoemulsions, liposomes, and niosomes. While the advantages and disadvantages of these delivery systems and information on stability, release, and efficacy of the nanodelivered EOs are covered in the literature as presented in this review, essential information, such as the speed of emergence of a potential bacteria resistance to these new systems, or dosages for each type of infection and for each animal species or humans is still missing today. Therefore, more quantitative and in vivo studies should be conducted before the adoption of EOs loaded NPs as an alternative to antibiotics, where appropriate.

Influence of biosynthesized silver nanoparticles using red alga Corallina elongata on broiler chicks’ performance

Poultry meat is a great source of protein and provides lots of nutrients such as iodine, iron, zinc, vitamins, and essential fatty acids that humans require. The positive applications of metal nanoparticles (NPs) in the diets of various poultry species were studied, in relation to their metabolic, antibacterial effects on digestion and regulation of bowel function. This study was carried out to test the effects of fabrication green silver nanoparticles (AgNPs) of Corallina elongata extract and/or coating NPs with acetic acid on performance, immune response parameters and micro-flora population in Ross broiler. Chicks’ drinking water was mixed with bio-AgNPs (1 mM) and coating NPs with acetic acid for 35 days. Fourier-transform infrared spectroscopy, electron dispersive spectroscopy (EDS) analysis, scanning electron microscopy, and high resolution transmission electron microscope were used to determine the partial physiochemical characterizations of bio-AgNPs and coating ones. EDS analysis was used to determine the presence of AgNP in meat. Results confirmed that coating NPs with acetic acid reduced percentage of the micro-flora population, which were detected by VITEK® 2 system (BioMérieux, France) and identified as Pseudomonas orizihabitain 4211210040000210 and Sphinogomonas paucimobilis 5201210040000210. EDS analysis of meat chicks confirmed disappearance of Ag metals. Coating biogenic AgNPs with acetic acid on modulated intestinal microbial populations of the Ross broiler may be safe, and could be used as alternative antibiotics or antibacterial agents besides their physiological performance in small intestines of broiler chicken.

Phytogenic Compounds for Enhancing Intestinal Barrier Function in Poultry-A Review

After the European Union ban of antibiotic growth promoters, works on different methods of improving gut health have intensified. The poultry industry is struggling with problems that were previously controlled by antibiotic growth promoters, therefore the search for optimal solutions continues. Simultaneously, there is also increasing social pressure to minimize the use of antibiotics and replace them with alternative feed additives. A variety of available alternatives is considered safe by consumers, among which phytogenics play a significant role. However, there are still some limitations that need to be considered. The most questionable are the issues related to bioavailability, metabolism of plant derivatives in birds, and the difficulty of standardizing commercial products. There is still a need for more evidence-based recommendations for the use of phytogenics in livestock. On the other hand, a positive influence of phytogenic compounds on the health of poultry has been previously described by many researchers and practical application of these compounds has auspicious perspectives in poultry production. Supplementation with phytogenic feed additives has been shown to protect birds from various environmental threats leading to impaired intestinal barrier function. Phytogenic feed additives have the potential to improve the overall structure of intestinal mucosa as well as gut barrier function on a molecular level. Recognition of the phytogenics' effect on the components of the intestinal barrier may enable the selection of the most suitable ones to alleviate negative effects of different agents. This review aims to summarize current knowledge of the influence of various phytogenic constituents on the intestinal barrier and health of poultry.

Butyric and Citric Acids and Their Salts in Poultry Nutrition: Effects on Gut Health and Intestinal Microbiota

Intestinal dysfunction of farm animals, such as intestinal inflammation and altered gut microbiota, is the critical problem affecting animal welfare, performance and farm profitability. China has prohibited the use of antibiotics to improve feed efficiency and growth performance for farm animals, including poultry, in 2020. With the advantages of maintaining gut homeostasis, enhancing digestion, and absorption and modulating gut microbiota, organic acids are regarded as promising antibiotic alternatives. Butyric and citric acids as presentative organic acids positively impact growth performance, welfare, and intestinal health of livestock mainly by reducing pathogenic bacteria and maintaining the gastrointestinal tract (GIT) pH. This review summarizes the discovery of butyric acid (BA), citric acid (CA) and their salt forms, molecular structure and properties, metabolism, biological functions and their applications in poultry nutrition. The research findings about BA, CA and their salts on rats, pigs and humans are also briefly reviewed. Therefore, this review will fill the knowledge gaps of the scientific community and may be of great interest for poultry nutritionists, researchers and feed manufacturers about these two weak organic acids and their effects on intestinal health and gut microbiota community, with the hope of providing safe, healthy and nutrient-rich poultry products to consumers.

Analysis of the Microbial Intestinal Tract in Broiler Chickens during the Rearing Period

Gut microbiota contributes to animal health. However, identifying which microorganisms or associated functions are involved remains, still, difficult to assess. In the present study, the microbiota of healthy broiler chickens, under controlled diet and farm conditions, was investigated by 16S rRNA gene sequencing in four intestine segments and at four ages. In detail, 210 Ross-308 male chickens were raised according to the EU guidelines and fed on a commercial diet. The duodenum, jejunum, ileum, and caecum microbiota were analyzed at 11, 24, 35, and 46 days of life. Although the microbial composition was revealed as homogeneous 11 days after chicks hatched, it was found to be similar in the proximal intestine segments and different in ileum and caecum, where almost the same genera and species were detected with different relative abundances. Although changes during the later growth stage were revealed, each genus remained relatively unchanged. Lactobacillus mostly colonized the upper tract of the intestine, whereas the Escherichia/Shigella genus the ileum. Clostridium and Bacteroides genera were predominant in the caecum, where the highest richness of bacterial taxa was observed. We also analyze and discuss the predicted role of the microbiota for each intestine segment and its potential involvement in nutrient digestion and absorption.

Microencapsulated phytogenic in dog feed modulates immune responses, oxidative status and reduces bacterial (Salmonella and Escherichia coli) counts in feces

Improving the health and immunity of pets is a concern of the guardians, while maintaining the health of the animals directly impacts the owners' health and public health. The objective of this study was to produce a dog feed containing a microencapsulated phytogenic blend, as well as determine the impact of the additive on animal health and its intestinal microbiota. The composition included microencapsulated thymol, carvacrol, and cinnamaldehyde, at 300 mg/kg of feed. Ten male beagle dogs were divided into two groups, identified as follows: the control group (C; ingested the feed without the additive) and the treated group (T; consumed feed containing the phytogenic blend). The dogs received 300 g of feed/day divided into two meals. Greater neutrophil counts in group T and lymphocyte counts were observed at the end of the experiment, as well as levels of α2-globulins and γ-globulin, while β1 and β2-globulins levels were lower in group T. Serum nitrogen oxide levels were higher in group T. Levels of reactive oxygen species were lower in group T at days 30 and 45, unlike activity of glutathione peroxidase that was higher. We found less bacterial contamination in the feces of dogs in group T, i.e., total bacterial count, total coliform counts, and counts of Salmonella and Escherichia coli were lower on days 30 and 45. Phytogenic blend intake reduces bacterial counts in stool and improves antioxidant/oxidative status and immune responses.

Effect of Acetic Acid and Sodium Bicarbonate Supplemented to Drinking Water on Water Quality, Growth Performance, Organ Weights, Cecal Traits and Hematological Parameters of Young Broilers

To evaluate the effect of acetic acid and sodium bicarbonate supplemented to drinking water on water quality, growth performance, relative organ weights, cecal traits and hematological parameters of broilers, a total of 456 one-day-old Cobb MV × Cobb 500 FF mixed broilers were randomly placed in three experimental treatments, with four replicates per treatment and 38 birds per replicate, for 10 days. The treatments consisted of the use of acetic acid (0.4%; T1) as acidifier, an apparently neutral pH (T2) and sodium bicarbonate (1%; T3) as alkalizer of the drinking water. T3 showed the highest values (p < 0.05) for total dissolved solids, electrical conductivity, salinity and pH. T1 and T2 showed the same productive response (p > 0.05); however, T3 decreased (p < 0.05) body weight, feed intake and the relative weight of the pancreas and immune organs and increased (p < 0.05) water intake, mortality and relative weight of the heart and liver. Likewise, T3 increased (p < 0.05) the cecal pH, although without changes for the cecal lactic cecal bacteria count and blood parameters (p > 0.05). The acid pH of the drinking water had no effect on the biological response of broilers compared to T2; however, the T3 provoked high mortality, ascites, low productivity and abnormal growth of some organs.

Time for a Paradigm Shift in Animal Nutrition Metabolic Pathway: Dietary Inclusion of Organic Acids on the Production Parameters, Nutrient Digestibility, and Meat Quality Traits of Swine and Broilers

Because the application of antibiotic growth promoters (AGP) causes accelerated adverse effects on the animal diet, the scientific community has taken progressive steps to enhance sustainable animal productivity without using AGP in animal nutrition. Organic acids (OAs) are non-antibiotic feed additives and a promising feeding strategy in the swine and broiler industry. Mechanistically, OAs improve productivity through multiple and diverse pathways in: (a) reduction of pathogenic bacteria in the gastro-intestinal tract (GIT) by reducing the gut pH; (b) boosting the digestibility of nutrients by facilitating digestive enzyme secretion and increasing feed retention time in the gut system; and (c) having a positive impact and preventing meat quality deterioration without leaving any chemical residues. Recent studies have reported the effectiveness of using encapsulated OAs and synergistic mechanisms of OAs combinations in swine and broiler productivity. On the other hand, the synergistic mechanisms of OAs and the optimal combination of OAs in the animal diet are not completely understood, and further intensive scientific explorations are needed. Moreover, the ultimate production parameters are not similar owing to the type of OAs, concentration level, growth phase, health status of animals, hygienic standards, and environmental factors. Thus, those factors need to be considered before implementing OAs in feeding practices. In conclusion, the current review evaluates the basics of OAs, mode of action, novel strategies to enhance utilization, influence on growth performances, nutrient digestibility, and meat quality traits of swine and broilers and their potential concerns regarding utilization.

Mandated restrictions on the use of medically important antibiotics in broiler chicken production in Canada: implications, emerging challenges, and opportunities for bolstering gastrointestinal function and health– A review

Chicken Farmers of Canada has been progressively phasing out prophylactic use of antibiotics in broiler chicken production. Consequently, hatcheries, veterinarians, and nutritionists have been mandated to contend with less reliance on use of preventive antibiotics. A topical concern is the increased risk of proliferation of enteric pathogens leading to poor performance, increased mortality and compromised welfare. Moreover, the gut harbors several taxa such as Campylobacter and Salmonella capable of causing significant illnesses in humans via contaminated poultry products. This has created opportunity for research and development of dietary strategies designed to modulate gastrointestinal environment for enhanced performance and food safety. Albeit with inconsistent responses, literature data suggests that dietary strategies such as feed enzymes, probiotics/prebiotics and phytogenic feed additives can bolster gut health and function in broiler chickens. However, much of the efficacy data was generated at controlled research settings that vary significantly with the complex commercial broiler production operations due to variation in dietary, health and environmental conditions. This review will summarize implications of mandated restrictions on the preventative use of antibiotics and emerging Canadian broiler production programs to meet processor specifications. Challenges and opportunities for integrating alternative dietary strategies in commercial broiler production settings will be highlighted.

Evaluation of Three Formulations of Essential Oils in Broiler Chickens under Cyclic Heat Stress

The objective of the present research was to assess the dietary supplementation of three formulations of essential oils (EO) in chickens under heat stress (HS). Day-of-hatch Cobb 500 chicks (n = 500) were randomly distributed into four groups: 1. HS control + control diets; 2. HS + control diets supplemented with 37 ppm EO of Lippia origanoides (LO); 3. HS + control diets supplemented with 45 ppm LO + 45 ppm EO of Rosmarinus officinalis (RO) + 300 ppm red beetroot; 4. HS + 45 ppm LO + 45 ppm RO + 300 ppm natural betaine. Chickens that received the EO showed significant (p < 0.05) improvement on BW, BWG, FI, and FCR compared to control HS chickens. Average body core temperature in group 3 and group 4 was significantly (p < 0.05) reduced compared with the HS control group and group 2. Experimental groups showed a significant reduction in FITC-d at 42 days, a significant increase in SOD at both days but a significant reduction of IFN-γ and IgA compared with HS control (p < 0.05). Bone mineralization was significantly improved by EO treatments (p < 0.05). Together these data suggest that supplemental dietary EO may reduce the harmful effects of HS.

Microencapsulated and uncoated butyric acid as alternative additives to the regeneration of intestinal mucosa in broilers challenged with Eimeria spp

1. The effect of microencapsulated and uncoated butyric acid as an alternative to antibiotics on performance, intestinal morphology and regeneration of intestinal mucosa was studied in birds experimentally infected with Eimeria spp. 1 to 42 d-old.2. A total of 1,320 male Cobb® broiler chicks were allocated to one of five treatments in a completely randomised design, comprising a negative control, uncoated butyric acid (UA), microencapsulated butyric acid (MA), combined U + M butyric acid and a positive control (antibiotic+anticoccidial) in six replications. At 16 d-old, the birds were inoculated orally with 0.5 ml of a solution containing an Eimeria spp. pool.3. At 21 d of age, the birds receiving butyric acid alone had higher body weight gain (BWG) and feed intake (FI) compared to those supplemented with the blend of acids. For the total rearing period, in all variables, the positive control performed best (P < 0.001).4. At 14 d of age, birds that received diets containing UA had a deeper crypt depth in the jejunum than those fed diets containing microencapsulated acid (P = 0.0194). At 21 d of age, the birds fed the acids had higher villi (P = 0.0058) in the duodenum, compared to the negative control group.5. Supplementation with microencapsulated acid contributed to the intestinal health and recovery of post-challenge birds, but did not result in improvements in performance.

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

Background

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

Results

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

Conclusion

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

Effects of Microencapsulated Blend of Organic Acids and Essential Oils as a Feed Additive on Quality of Chicken Breast Meat

The present study aims to investigate the effect of dietary supplementation based on a blend of microencapsulated organic acids (sorbic and citric) and essential oils (thymol and vanillin) on chicken meat quality. A total of 420 male Ross 308 chicks were randomly assigned to two dietary treatments: the control group was fed with conventional diet (CON), while the other group received the control diet supplemented with 0.5% of a microencapsulated blend of organic acids and essential oils (AVI). In breast meat samples, intramuscular fat content and saturated/polyunsaturated fatty acids ratio were reduced by AVI supplementation (p < 0.05). Moreover, atherogenic (p < 0.01) and thrombogenic (p < 0.05) indices were lower in AVI than CON treatment. AVI raw meat showed a lower density of psychrotrophic bacteria (p < 0.05) at an initial time, and higher loads of enterococci after 4 days of refrigerated storage (p < 0.05). No contamination of Listeria spp., Campylobacter spp., and Clostridium spp. was found. TBARS values of the cooked meat were lower in the AVI treatment compared to CON (p < 0.01). Among colour parameters, a*, b* and C* values increased between 4 and 7 days of storage in AVI cooked meat (p < 0.05). Overall, organic acids and essential oils could improve the quality and shelf-life of poultry meat.

Effects of encapsulated essential oils and organic acids on laying performance, egg quality, intestinal morphology, barrier function, and microflora count of hens during the early laying period

The objective of this study was to investigate the effect of encapsulated essential oils and organic acids (EOA) on the growth performance, egg quality, intestinal morphology and functions, and microbial count of laying hens from week 21 to 30. A total of five hundred and four 21-wk-old layers were randomly allotted into 4 groups consisting of 7 replicates with 18 birds per replicate. The birds were fed a basic diet (CON) or diets with EOA at 150 mg/kg, 300 mg/kg, and 450 mg/kg in the other 3 groups, respectively. Compared to the CON group, the addition of 150 mg/kg EOA significantly increased laying rate (P < 0.05) of hens from week 21 to 25. A linear increasing (linear, P < 0.01) in ileal villus height of laying hens fed EOA from 150 to 300 mg/kg was observed at week 30. At week 25, the supplementation of 300 mg/kg EOA significantly increased (P < 0.05) mRNA relative expression of aminopeptidase, sodium-glucose cotransporter 1, and Na+-independent neutral amino acid transporter in duodenum and glucose transporter 2 in jejunum of laying hens compared to the CON groups. Meanwhile, the relative expression of glucose transporter 2 mRNA in the jejunum was upregulated with increasing concentration of EOA in diets (linear, P < 0.05). Hens in EOA 300 group had higher mRNA relative expression of mucin-2 in ileum (P < 0.05) than hens in CON group. Additionally, the secretory immunoglobulin in ileum A were linear decreased (linear, P < 0.01) with the increasing supplement of EOA. Dietary supplementation with EOA tended to increase (P = 0.083) the counts of Bifidobacterium in cecal digesta at week 25 and 30. In conclusion, dietary with EOA may maintain intestinal tract morphology and promote digestive and absorptive capacities and barrier function, especially at 300 mg/kg. This study provided evidence of using EOA as a potential feed additive for laying hens.

Effects of Microencapsulated Blends of Organics Acids (OA) and Essential Oils (EO) as a Feed Additive for Broiler Chicken. A Focus on Growth Performance, Gut Morphology and Microbiology

Simple Summary

Replacing antibiotics with natural alternative compounds in poultry feeding is being increased in the last few years to challenge the antibiotic resistance problem. Among natural compounds, organic acids and essential oils could be a favorable option. The goal of the trial was testing the dietary supplementation of a blend of organic acids and essential oils in broiler diets in order to evaluate growth performance and gut healthiness. The blend of organic acids and essential oils improved growth performances at the end of the growing period and favorably affected, to a certain extent, gut morphology at different gut districts. Moreover, a selective microbial control against Clostridium perfringens, Enterobacteriaceae, Enterococci and Mesophilic bacteria was found. Additionally, in litter, organic acids and essential oils dietary treatment drove to an overall decrease of Mesophilic bacteria and Enterococci counts. Overall, dietary strategy oriented to a supplementation of a mixture of organic acids and essential oils in broiler diets could offer some favorable perspectives in order to maintain adequate growth performance and gut healthiness either in term of morphology or of microbiology. Nevertheless, improving knowledge on the mechanisms of action of these natural additives together with a potential synergistic action is pivotal to clarify their potential as antibiotic replacers.

Abstract

The goal of the trial was testing the effects of a blend of organic acids and essential oils dietary supplementation on growth performance and gut healthiness in broiler chickens. In total, 420 male Ross 308 chicks (1-day old) were randomly assigned to two dietary treatments: basal (BD) and organic acids and essential oils (OA&EO) diets (three replicates/treatment; 70 broilers/replicate). BD group received commercial diets whereas OA&EO group basal diets + 5 g/kg of microencapsulated organic acids and essential oils. OA&EO treatment improved the average daily gain (p < 0.01) and feed conversion ratio at 37–47 days compared to BD treatment. OA&EO treatment improved gut morphology mostly at ileum and duodenum levels in terms of villi height, crypt depth, number of villi, mucosa thickness and villi area at 24 and 34 sampling days. A certain selective action against Clostridium perfringens in ileum of OA&EO group was shown at 33 (p = 0.053) and 46 days (p = 0.09) together with lower median values for Enterobacteriaceae, Enterococci, Mesophilic bacteria and Clostridium perfringens at ceca level. Overall, organic acids and essential oils supplementation improved growth performance in the final growth stage and some morphological gut traits and reduced to a certain extent Clostridium perfringens count in ileum.

Single components of botanicals and nature-identical compounds as a non-antibiotic strategy to ameliorate health status and improve performance in poultry and pigs

In the current post-antibiotic era, botanicals represent one of the most employed nutritional strategies to sustain antibiotic-free and no-antibiotic-ever production. Botanicals can be classified either as plant extracts, meaning the direct products derived by extraction from the raw plant materials (essential oils (EO) and oleoresins (OR)), or as nature-identical compounds (NIC), such as the chemically synthesised counterparts of the pure bioactive compounds of EO/OR. In the literature, differences between the use of EO/OR or NIC are often unclear, so it is difficult to attribute certain effects to specific bioactive compounds. The aim of the present review was to provide an overview of the effects exerted by botanicals on the health status and growth performance of poultry and pigs, focusing attention on those studies where only NIC were employed or those where the composition of the EO/OR was defined. In particular, phenolic compounds (apigenin, quercetin, curcumin and resveratrol), organosulfur compounds (allicin), terpenes (eugenol, thymol, carvacrol, capsaicin and artemisinin) and aldehydes (cinnamaldehyde and vanillin) were considered. These molecules have different properties such as antimicrobial (including antibacterial, antifungal, antiviral and antiprotozoal), anti-inflammatory, antioxidant, immunomodulatory, as well as the improvement of intestinal morphology and integrity of the intestinal mucosa. The use of NIC allows us to properly combine pure compounds, according to the target to achieve. Thus, they represent a promising non-antibiotic tool to allow better intestinal health and a general health status, thereby leading to improved growth performance.

Protected Blend of Organic Acids and Essential Oils Improves Growth Performance, Nutrient Digestibility, and Intestinal Health of Broiler Chickens Undergoing an Intestinal Challenge

The growing restriction of antibiotic growth promoters (AGP) use in farming animals has raised a concern regarding the viability of the animal production system. In this new context, feed additives with proven positive impact on intestinal health may be used as strategy to avoid losses on performance. The aim of this study was to evaluate the effects of a protected blend of organic acids and essential oils [P(OA+EO)] on growth performance, nutrient digestibility, and intestinal health of broiler chickens. A total of 1,080 Cobb × Cobb 500 male broilers were randomly distributed in four treatments with 10 replicates (27 birds/each). Treatments were as follow: non-challenged control; challenged control; AGP (enramycin at 10 g/t); and P(OA+EO) at 300 g/t. All birds on challenged groups were challenged with Eimeria spp. at 1 day and with Clostridium perfringens at 11, 12, and 13 days. Body weight gain (BWG), feed intake and feed conversion ratio (FCR) were evaluated until 42 days. At 17 days, one bird per pen was orally gavaged with fluorescein isothiocyanate-dextran (FITC-d) and blood samples were collected for FITC-d detection to assess intestinal permeability. At 21 days, apparent ileal nutrient and energy (IDE) digestibility, intestinal macroscopic and histologic alterations (ISI) and, expression of mucin2 (MUC2), claudin1 (CLDN1), and occludin (OCLN) genes in the jejunum were evaluated. From 1 to 42 days, birds from the non-challenged and P(OA+EO) groups had greater (P < 0.001) BWG compared to challenged control and AGP groups. The challenged control group presented the worst FCR (P < 0.001). IDE was 106 kcal/kg greater when broilers were fed P(OA+EO) compared to the challenged control group. Broilers supplemented with P(OA+EO) had improved intestinal integrity with lower blood FITC-d concentration and ISI scores, and greater expression of MUC2, CLDN1, and OCLN genes compared to the challenged control group (P < 0.05). In conclusion, the P(OA+EO) and the AGP led to increased growth performance, nutrient digestibility and intestinal health of challenged broilers. A marked difference occurred in favor of the P(OA+EO), suggesting that this blend may be used to improve intestinal health and broiler growth performance in AGP free programs.

Growth performance and gastrointestinal responses in heavy Tom turkeys fed antibiotic free corn-soybean meal diets supplemented with multiple doses of a single strain Bacillus subtilis probiotic (DSM29784)1

Growth performance and gastrointestinal (GIT) responses to a single-strain of Bacillus subtilis (SSB) were investigated using 960 Hybrid Converter Toms. A total of 4 iso-caloric and iso-nitrogenous corn-soybean meal-based diets were allocated to 12 replicate cages/pens and fed (ad libitum) in a four-phase feeding program (starter; days 0 to 28, grower-1; days 29 to 56, grower-2; days 57 to 84, and finisher; days 85 to 126). The diets had either 0 (control), 1E+08 (low), 2E+08 (mid) or 1E+09 (high) cfu B. subtilis/kg. Feed intake (FI) and BW were recorded by phase. Excreta samples were collected towards the end of starter and grower-1 phases for apparent retention (AR) of components by marker method and litter moisture, respectively. Selected birds were necropsied on days 28 and 56 for GIT weight and samples for jejunal histomorphology and ceca digesta short chain fatty acids (SCFA). Supplemental SSB had linear and non-linear (P < 0.05) response on BW gain (BWG). Specifically, relative to the control, birds fed low SSB had higher BWG in starter and grower-1 phases whereas bird fed mid and high SSB had lower BWG in grower-2 and birds fed low and mid SSB had higher BWG in finisher phase. Consequently, birds fed low and mid SSB doses were heavier (P < 0.05) than control fed birds at the end of trial. The FCR response to SSB was linear and non-linear (P < 0.05) with birds fed low SSB showing lower FCR than control fed birds in starter, grower-1 and finisher phases. Supplemental SSB had linear and non-linear (P < 0.05) effects on AR of components (DM, ash, crude protein, crude fat, neutral detergent fiber, and gross energy), litter moisture, GIT weight, jejunal histomorphology, and SCFA. Relative to control, birds fed high SSB showed higher AR of components, villi height, day 56 ceca digesta total SCFA concentration, and lower litter moisture. In conclusions, under condition of the current study, growth performance was optimized by low to mid SSB. Improved nutrient retention and indices of gut health suggested higher SSB doses may optimize growth performance under challenging farm conditions.

Influence of Two Plant Extracts on Broiler Performance, Oxidative Stability of Meat and Odorous Gas Emissions from Excreta

A feeding trial was conducted to evaluate the effects of plant extracts derived from Mentha arvensis (MA) and Geranium thunbergii (GT) on broiler performance, carcass yield, digestive organ weights, meat quality and odorous gas emissions from the excreta. A total of 210 one-day-old broiler chicks were randomly assigned to one of the following dietary treatments for five weeks: (1) control, (2) 0.1% MA, (3) 0.05% GT, (4) 0.1% GT and 0.1% mixed preparation with varying ratios such as (5) 0.1% 1MA:1GT, (6) 0.1% 1MA:4GT and (7) 0.1% 4MA:1GT. The weight gain (0–3 weeks) was significantly (P<0.01) increased in response to dietary inclusion of plant extracts; however, no significant differences were observed in breast and thigh meat yield (P>0.05). Additionally, no differences were observed in proventriculus, gizzard, pancreas, small and large intestine weight. When compared with the control group, birds fed plant extracts had the lowest meat TBARS value after 0 and 3 weeks of storage (P<0.05). Moreover, the pH value was significantly lower (P<0.05) in the plant extract supplemented groups at 0 weeks. The faecal H2S emissions were significantly reduced at 0 h and 6 h in all supplemented groups relative to the control (P<0.05). Similarly, NH3 emissions were reduced at 0 h and 6 h for all supplemented groups except the 0.1% 1MA:1GT group (P<0.05). Overall, the results of the present study indicate that plant extracts supplementation can be used to improve performance and meat quality of broiler chickens while reducing the emission of harmful gases from the excreta.

Essential Oils as Feed Additives-Future Perspectives

The inconsistency of phytogenic feed additives' (PFA) effects on the livestock industry poses a risk for their use as a replacement for antibiotic growth promoters. The livestock market is being encouraged to use natural growth promotors, but information is limited about the PFA mode of action. The aim of this paper is to present the complexity of compounds present in essential oils (EOs) and factors that influence biological effects of PFA. In this paper, we highlight various controls and optimization parameters that influence the processes for the standardization of these products. The chemical composition of EOs depends on plant genetics, growth conditions, development stage at harvest, and processes of extracting active compounds. Their biological effects are further influenced by the interaction of phytochemicals and their bioavailability in the gastrointestinal tract of animals. PFA effects on animal health and production are also complex due to various EO antibiotic, antioxidant, anti-quorum sensing, anti-inflammatory, and digestive fluids stimulating activities. Research must focus on reliable methods to identify and control the quality and effects of EOs. In this study, we focused on available microencapsulation techniques of EOs to increase the bioavailability of active compounds, as well as their application in the animal feed additive industry.

Effects of organic acids and essential oils blend on growth, gut microbiota, immune response and disease resistance of Pacific white shrimp (Litopenaeus vannamei) against Vibrio parahaemolyticus

An 8-week feeding trial was undertaken to evaluate supplemental effects of AviPlus^® (AP), a blend of organic acids [citric acid, 25%; sorbic acid, 16.7%] and essential oils [thymol, 1.7%; vanillin, 1.0%], on growth, gut microbiota, innate immunity and disease resistance of Pacific white shrimp (Litopenaeus vannamei) against Vibrio parahaemolyticus. A basal experimental diet was formulated and supplemented with 0, 0.3, 0.6, 0.9 and 1.2 g kg^-1 AP to produce five test diets (Con, AP0.3, AP0.6, AP0.9 and AP1.2). Each diet was fed to triplicate groups of shrimp (0.2 ± 0.01 g, mean ± SE) to apparent satiation three times daily. Growth performance and survival rate were not significantly influenced by AP supplementation (P > 0.05). Significantly (P < 0.05) higher serum total protein was found in groups fed ≥ 0.6 g kg^-1 AP compared to control. Serum alkaline phosphatase and phenoloxidase activities were significantly increased in AP0.9 and AP1.2 groups. Also, the group received AP0.6 diet showed significantly higher glutathione peroxidase activity than control. Expression of gut pro-inflammatory genes including TNF-α, LITAF and RAB6A were down-regulated by AP administration. Gut microbiota analysis showed the significant enhancement of the operational taxonomic unit (OTU) diversity and richness indices by AP application. AP supplementation led to increased abundance of Firmicutes and a reduction in abundance of Proteobacteria. Also, dietary inclusion of 1.2 g kg^-1 AP led to a significant increase in the abundance of Lactobacillus in shrimp gut. The group offered AP0.3 diet showed significantly higher disease resistance than control group. Furthermore, AP application significantly enhanced relative expression of immune related genes including lysozyme, penaeidin and catalase at 48 h post challenge. In conclusion, these findings show that the tested organic acids and essential oils mixture beneficially affects intestinal microflora and improves immune response and disease resistance of L. vannamei.