EFFICACY OF PROBIOTICS AND ESSENTIAL OILS AS ALTERNATIVES TO ANTIBIOTIC GROWTH PROMOTERS IN BROILER CHICKENS

Abstract

The current study was carried out on broiler chickens to assess whether probiotics or essential oils could be utilized instead of antibiotics growth promoters (AGP) in typical feed formulations, to determine their effectiveness. A total of 2250 broiler chicks at one-day old age were allocated into 5 dietary treatments in a completely randomized design with 9 replicates per treatment and 50 chicks/replicate. The Probiotic included three strains of Bacillus amyloliquefaciens, the essential oil (EO) was a blend of Cinnamaldehyde-Thymol, and the AGP was Lincomycin™. These additives were added to the basal diets (BD) to formulate the following dietary treatments (T): (Tl) control-fed BD that is regularly used by broiler farmers (T2) control-fed BD that is regularly used by broiler farmers and supplemented with Lincomycin™ (100 g/ton) as AGP; (T3) fed BD + Probiotics (Enviva® PRO 60 g/ton); (T4) fed BD + EO (Enviva® 100g/ton); and (T5) fed BD + combination of both probiotics and EO with the same doses used in T3 and T4. The study findings demonstrated that the use of probiotics or essential oils did not have any significant impact on the average body weight gain, final body weight, feed conversion ratio, or footpad lesion scores when compared to the AGP group. It was concluded that replacing the AGP with probiotics or EO, as natural feed additives, had no negative effects on broiler performance. The probiotic strains or the EO could be safe alternatives to AGP.

Headnote

ABSTRACT

The current study was carried out on broiler chickens to assess whether probiotics or essential oils could be utilized instead of antibiotics growth promoters (AGP) in typical feed formulations, to determine their effectiveness. A total of 2250 broiler chicks at one-day old age were allocated into 5 dietary treatments in a completely randomized design with 9 replicates per treatment and 50 chicks/replicate. The Probiotic included three strains of Bacillus amyloliquefaciens, the essential oil (EO) was a blend of Cinnamaldehyde-Thymol, and the AGP was Lincomycin™. These additives were added to the basal diets (BD) to formulate the following dietary treatments (T): (Tl) control-fed BD that is regularly used by broiler farmers (T2) control-fed BD that is regularly used by broiler farmers and supplemented with Lincomycin™ (100 g/ton) as AGP; (T3) fed BD + Probiotics (Enviva® PRO 60 g/ton); (T4) fed BD + EO (Enviva® 100g/ton); and (T5) fed BD + combination of both probiotics and EO with the same doses used in T3 and T4. The study findings demonstrated that the use of probiotics or essential oils did not have any significant impact on the average body weight gain, final body weight, feed conversion ratio, or footpad lesion scores when compared to the AGP group. It was concluded that replacing the AGP with probiotics or EO, as natural feed additives, had no negative effects on broiler performance. The probiotic strains or the EO could be safe alternatives to AGP.

Keywords: cinnamaldéhyde, thymol, feed conversion ratio, footpad lesion, additives

INTRODUCTION

The growing awareness of the interconnection between health, and nutrition in the broiler industry has sparked a surge of interest in seeking suitable alternative products to antibiotic growth promoters (AGP) which used to improve performance (5, 11). One of the main concerns is developing antibioticresistant bacteria. European Union banned the use of most AGP in broiler diets due to multiple and/or cross-resistance (37). Crossresistance against pathogens and antibiotic residues in tissues was previously confirmed by (14). (40) proposed that the intensive use of antibiotics in broiler diets led to increased resistance lines of microorganisms. Numerous types of alternatives to AGP are developed such as probiotics, prebiotics, symbiotic, organic acids, and essential oils (EO). Alternative efficacy can differ depending on several factors such as nutrition, management practices, and environmental conditions (22). Probiotics are live microorganisms (bacteria or yeast) that are naturally found in the gut of animals. Probiotics work by keeping balance of useful bacteria in the gut, in order to help improve nutrient digestion, absorption, boost immunity, and reduce the disease threats (39, 40). Additionally, they support inhibition harmful bacteria growth in the gut by competing for nutrients and adhesion sites (16, 41, 34). Essential oils are organic plant extracts known as phytogenic compounds (35). They have several benefits as improving growth performance (4,53), gut health (24, 50, 20), enhancing immunity (1,19), and improving' meat quality (44). Beneficial effects of probiotics and EO reported widely such as improving weight gain, promoting feed intake, enhancing digestion, and increasing feed conversion efficiency (6, 13, 33), Another advantage is that it increases enzyme activity by stimulating the animal's digestive system, increases metabolism and use of digestive products, and improves liver functioning (23, 25). Probiotics and EO play an essential role as antimicrobial active substances that reduce colonization of pathogens and invasion in the host digestive system to eliminate various enteric infections (17,48,52). Thymol was identified by (21) as one of the strongest bioactive antimicrobials among all phytochemicals. It is the major component of thyme EO, and the substance is found in plants such as Thymus vulgaris it is recognized for its ability to target bacterial membranes and generate pores that permit the release of substances from the cell and the entry of chemicals from outside the cell (36). Cinnamaldéhyde is naturally occurring plantderived chemical with antibacterial action that has the potential to be used instead of conventional antibiotics (18). Cinnamaldéhyde attacks proteins involved in generating energy for bacteria (36). This mode of action is considered to be crucial in giving broad coverage against both types of bacteria the gram-negative and gram-positive (36). The efficacy of each thymol and Cinnamaldéhyde blend to have antimicrobial activities against C. perfringens is stated in several poultry researchs (32). Bacillus strains, particularly those of the amyloliquefaciens type, have been discovered as probiotic bacteria that help to create and maintain a balanced microbial population in the host animal's gut (9). Increased beneficial bacteria colonization makes the gut environment less favorable to coliform colonization and aids in maintaining optimal villi height and crypt depth, assuring the gut's capacity to absorb nutrients for animal maintenance and growth (28). On the other hand, probiotics have been demonstrated to elicit a beneficial impact on the immune system of broiler by stimulating the development of gut-associated lymphoid tissue and enhancing the activity of immune cells (15, 30). Probiotics interact with the goblet cells, M cells from the Peyer's patches, and enterocytes, increasing the number of IgAproducing cells along with producing IgM and IgA, which is important for the immunity of the mucosa because it forms a barrier against pathogenic microorganisms (29). This study aims to find safe alternative for AGP. The study hypothesized that using either probiotics, EO, or both will improve the overall performance of broiler chickens and will be a substitute for AGPs.

MATERIALS AND METHODS

Study Location, Feed, and Test Products

The University of Jordan's Scientific Research Council authorized the experimental methodology. This experiment was carried out at AL-Estesharia company research facility, Amman, Jordan. AL-Estesharia Research facility is a state-of-art research facility for field experiments on poultry. The laboratory works and analyses were carried out at the University of Jordan, school of Agriculture and AL-Estesharia lab. Feed was produced at AL-Estesharia feed mill. Three phases basal diets (starter, grower, and finisher) were produced and used for all treatments. The basal diets were formulated to be Antibioticand Coccidiostat-free. The composition and nutrients content of the basal diets were formulated in a specialized computer program (Brill Software VI.36.017) to meet the broiler nutrients requirement according to the strain commercial guideline (Ross 308 Strain Guideline). All diet types were iso-caloric and iso-nitrogenous. Table 1 shows the nutritional composition of the basal diets. Five samples of 200 g each, from each diet type were collected and thoroughly mixed (total=1000g) and sent to perform chemical analysis of feed composition (Gross energy, crude protein, amino acids profile, moisture, ash, crude fat, starch, sugar, crude fiber, phosphorus, calcium, and sodium). Feed analyses was conducted at AL-Estesharia Lab. A subsample of 200g sent to Danisco labs-Germany for a recovery test of Bacillus amyloliquefaciens and thymolcinnamaldehyde blend to ensure the homogeneity of mixing before launching up the trial. The experiment started upon receiving homogeny approval from Danisco. At the research center, one metric ton from each diet produced firstly to flush out the production lines then excluded to make sure that production lines are clean of any previous residues from other rations. Test products weighed separately and added to feeds in automated highly sensitive injectors. Three commercial products were used in this experiment. The recommended dosage of these products was according to the manufacturer. The description of the three commercial products were as the following: Bacillus amyloliquefaciens Strains (Probiotics) provided by Enviva® PRO (Danisco Animal Nutrition, USA). It is a probiotic contains three strains of Bacillus amyloliquefaciens isolated from intestinal tracts of healthy chickens: BS15AP4, BS8 and BS2084. It is provided in powder form with a concentration of 2.5x109 CFU/g, and it is a thermo-stable product. The recommended dose for broiler chickens is 60 g of the product/MT feed.

Essential Oils (EO) provided by Enviva® EO (Danisco Animal Nutrition, UK). It is a combination of Cinnamaldéhyde and Thymol aromatic molecules that have been formed by the carrier phase using maltodextrin gum mixed with oil phase of cinnamaldéhyde and oil then homogenized carefully, encapsulated with glass like surface, dried as early stage drying then dried again as later stage drying and finally agglomerated in the final form of product from specific plants or plant parts. The concentration of cinnamaldéhyde (2E)-3Phenylprop-2-enal is 4.5 %, while the Thymol (2-isopropyl-5-methylphenol, IPMP) concentration is 13.5%. The product is provided in encapsulated powder form, it is a thermo-stable product. The recommended dose for broiler chickens is 100 g/MT feed.

The Antibiotic Growth Promoter (AGP) provided by LINCOMIX 44 (Zoetis). It is a broad-spectrum antibiotic used for poultry and consists of Lincomycin hydrochloride. The Lincomycin concentration is 4.4% as Lincomycin hydrochloride. The recommended dose as a growth promoter in broiler chickens is 50-100 g/ MT feed. This AGP was chosen because it is widely used in Jordan broiler farms as prophylactic and as AGP (Personal communication).

Five samples of 200 g each, from each diet type were collected and thoroughly mixed (total= 1000g) and sent to perform chemical analysis of feed composition (Gross energy, crude protein, amino acids profile, moisture, ash, crude fat, starch, sugar, crude fiber, phosphorus, calcium, and sodium). Feed analyses was conducted at AL-Estesharia Lab. A sub-sample of 200g sent to Danisco labsGermany for a recovery test of Bacillus amyloliquefaciens and thymolcinnamaldehyde blend to ensure the homogeneity of mixing before launching up the trial. The experiment started upon receiving homogeny approval from Danisco. At the research center, one metric ton from each diet produced firstly to flush out the production lines then excluded to make sure that production lines are clean of any previous residues from other rations. Test products weighed separately and added to feeds in automated highly sensitive injectors. Three commercial products were used in this experiment. The recommended dosage of these products was according to the manufacturer. The description of the three commercial products were as the following: Bacillus amyloliquefaciens Strains (Probiotics) provided by Enviva® PRO (Danisco Animal Nutrition, USA). It is a probiotic contains three strains of Bacillus amyloliquefaciens isolated from intestinal tracts of healthy chickens: BS15AP4, BS8 and BS2084. It is provided in powder form with a concentration of 2.5x109 CFU/g, and it is a thermo-stable product. The recommended dose for broiler chickens is 60 g of the product/MT feed. Essential Oils (EO) provided by Enviva® EO (Danisco Animal Nutrition, UK). It is a combination of Cinnamaldéhyde and Thymol aromatic molecules that have been formed by the carrier phase using maltodextrin gum mixed with oil phase of cinnamaldéhyde and oil then homogenized carefully, encapsulated with glass like surface, dried as early stage drying then dried again as later stage drying and finally agglomerated in the final form of product from specific plants or plant parts. The concentration of cinnamaldéhyde (2E)-3Phenylprop-2-enal is 4.5 %, while the Thymol (2-isopropyl-5-methylphenol, IPMP) concentration is 13.5%. The product is provided in encapsulated powder form, it is a thermo-stable product. The recommended dose for broiler chickens is 100 g/MT feed. The Antibiotic Growth Promoter (AGP) provided by LINCOMIX 44 (Zoetis). It is a broadspectrum antibiotic used for poultry and consists of Lincomycin hydrochloride. The Lincomycin concentration is 4.4% as Lincomycin hydrochloride. The recommended dose as a growth promoter in broiler chickens is 50-100 g/ MT feed. This AGP was chosen because it is widely used in Jordan broiler farms as prophylactic and as AGP (Personal communication).

Birds and Experimental Design

A commercial hatchery provided 2250 1-dayold broiler chicks from Ross 308 strain. Chicks are reared till 42 days of age in accordance with standard management and practices provided by the strain management guidelines. Birds were reared on floor pens at a fully closed poultry house equipped with full automated systems installed specifically for research purposes. The dimensions of the house are 48 X 10 m. It is composed of 54 floor pens (1.7m X 1.64m), where each pen can accommodate up to 50 broiler birds. Each two adjacent pens are separated by a robust heavy-duty plastic mesh with an ideal opening size of 181 cm height to prevent birds from escaping or mingling, especially at young ages. This house heating is provided by an autonomous infrared heating system that maintains the proper temperature as needed. In this housing, an autonomous negative pressure system with the necessary sensors is built to provide adequate ventilation that is consistent with the age and weight of the birds. This house's precise environmental parameters (temperature, ventilation, and air velocity) are ensured by an automatic computerized control panel. Feeding is controlled through manual hanging circular feeders with adjustable height to align age of birds. Similarly, automated hanging nipple drinkers supply birds with clean water in each pen. The rearing cycle was divided into 3 stages: started with starter phase at 0 days of age up to 14 days followed with grower phase from 15 days up to 28 days and ended up with finisher phase from 29 days to 42 days. According to Ross 308 strain specifications, feed and water were supplied ad libitum, with a lighting schedule includes 20 hours of light followed by 4 hours of darkness. In a fully randomized design (CRD), broiler chicks were randomly assigned to one of four nutritional treatments, with nine repetitions (pens) per treatment and 50 birds each replication. There were 450 birds in each treatment. The Probiotic, essential oils, and AGP were added to the standard commercial basal diets (BD) for broiler chickens to formulate 5 dietary treatments (T) as the following:

Tl: Control diet; the regular commercial broiler diets (Table 1).

T2: Control diet+ Lincomycin (100 g/ton; recommended dosage), used as AGP.

T3: Control diet + Probiotics "Enviva® PRO" (60 g/ton; recommended dosage).

T4: Control diet + Essential oils "Enviva® EO" (100g/ton; recommended dosage).

T5: Control diet + Mixture of probiotics and EO (same doses as in T3&T4).

Growth Performance Parameters Average Body Weight

Birds were weighed at weekly basis and overall period results recorded at 42 days of age, all birds in each pen used for weighing (the whole pen were taken), and then treatment average body weight (BW) determined.

Feed Intake: Feed intake (FI) for each floor pen was calculated in weekly basis and the total consumed feed measured at 42 days of age, then calculated as total amount of provided feed for each pen each day dived by total numbers of chicks.

Feed Conversion Ratio

Feed conversion ratio (FCR) was calculated at weekly basis and total FCR at 42 of age recorded. It was calculated as the amount of FI dived by average body weight gain (differences between the current weight and previous weight). FCR was corrected for mortality in each pen by weighing the dead bird and use below formula to calculate estimated feed intake:

Estimated feed intake = FCR · Weight

To calculate B W gain the initial B W subtracted from final BW. Feed intake was calculated by subtracting estimated feed intake for mortality and remined feed from the whole quantity of feed offered to the birds. The FCR was calculated weekly and as a total at the end of the trial using data from FI and B W gain.

Mortality

On a pen-by-pen basis, all dead birds have been recorded and weighed. In order to find the reason, dead birds were necropsied.

Foot Pad Lesion Score (FBD). Two birds from each floor were collected for foot and pad lesion examination at day 28 of age. The methodology for foot pad lesion scoring was conducted according to (10) where: 0: No no visible symptoms of FPD, and the skin of the foot pad feels soft to the touch with no swelling or necrosis; 1 : shows slight redness to the foot pad, and the pad textures look tougher and denser than a non-affected foot, the central part of the pad is higher, reticulate scales are detached, besides presence of small black necrotic areas; 2: shows visible lesions appear on foot pad surface, obvious swelling appearance of the foot pad, reticulate scales are black in addition to forming scale shaped necrotic areas.

Statistical Analysis

All statistical analysis was carried out using the Statistical Analysis System (SAS Institute, 2010, Version 9.1.3) (45). The replicate was considered as the experimental unit (pen) and was analyzed using one-way ANOVA implemented in the proc GLM method of SAS. When P<0.05, differences were accepted as statistically significant differences. Tukey's test used to split means for significant interactions.

RESULTS AND DISCUSSION

Growth Performance Parameters

Tables 2 and 3 show the effect of various treatments on growth performance parameters. At DO, the initial body weight of chicks was similar, no significant variation between treatments (Table 2). The growth rate for the birds in the different treatments followed the normal pattern and was the same. The results of final weight were the same with no significant differences found in the treatments compared to the control treatment (Table 2). In addition, the results for average body weight gain showed that there is no statistical differences in the treatments relative to the control treatment (Table 2). Recorded Feed intake data did not show any significant variation between groups as demonstrated below in (Table 3). Likewise, the outcomes of the calculated FCR demonstrated no significant variances in the treatments when compared to the control treatment (Table 3). Recorded mortality % were within the normal accepted values under large scali field trial in jordan, no disease challenges observed during the trial and no significant differences recorded among groups (Table 3).

Footpad Lesions

Table 4 illustrates the impact of various treatments on footpad lesion scores. The results revealed that none of the treatments had a significant impact on the foot pad lesions scores in comparison with control diet.

The purpose of this study was to investigate if three Bacillus amyloliquefaciens probiotic strains and a thymol-cinnamaldehyde mix (EO) might improve broiler chicken performance and if the supplements could possibly be used as an alternative to AGP. During the trial period, no significant effect of the probiotic or EO on broiler chicken performance parameters as body weight and/or body weight gain or FCR was seen, relative to the control treatment that had supplemented with AGP. This results in consistence with results obtained by (8) in trial conducted to evaluate adding probiotics, prebiotics and synbiotics. The lack of the differences between broilers supplemented with probiotics and the control treatment (supplemented with AGP) indicating that broilers in T2 were able to get the beneficial effects out of the probiotic and to successfully substitute the AGP. Under normal conditions (non-challenging circumstances), the utilization of probiotic strains and EO resulted in performance results comparable to broiler chickens in the control treatments, with no significant differences found. Probiotic supplementation has been suggested as an alternative to AGP in poultry diet due to their potential to improve performance and health (2,7). The potential benefits of providing probiotics in broiler diets have been extensively investigated. Probiotics are known to combat harmful microorganisms in the digestive system of chickens (47) improve growth rate (3), enhance immune system (43) improve gut health by promote beneficial microorganism and suppress the pathogenic once (52). Probiotics have been known to improve gut health by promote beneficial bacteria and suppressing pathogenic bacteria with create aggressive environment for harmful bacterial through reducing pH; competing for nutrients, inhibit bacterial adherence and translocation and produce antibacterial substances as bacteriocins (38, 46). In addition, probiotics have been reported to have a positive effect on footpad lesions in broiler chickens. Footpad lesions are a common welfare issue in broiler chickens, it might be caused by different reasons such as poor litter quality, high ammonia levels, and bacterial infections. The beneficial probiotics effects such as improving gut health, increasing feed absorption and utilization in the gut might help in reducing harmful bacterial and thus prevent or reduce the incidence of footpad lesions. Our findings indicated that probiotics supplementation in broiler diets improved broilers growth parameters. Likewise, the results obtained by EO supplementation were similar to what was obtained by probiotics. (26) and (49) found a significant positive effect of EO on FOR and body weight gain of broiler chickens in comparison with an unsupplemented control group. Essential oils are aromatic compound found in plants that are hydrophobic in nature. They can either be naturally derived from plants or created synthetically (31). It was reported that EO have both preventative and healing effects on necrotic enteritis in broiler chickens (27), exerts a beneficial influence on broilers growth, meat and carcass quality and overall health (31), and improved FOR (42). Similarly, it was found that using both probiotics and EO in the broiler diets improved the performance parameters during the experimental period.

Conclusion

The results indicated that using probiotics, EO, or their combination in broiler diets might be one of the promising strategies that might be applied in the field to stop using AGP without any negative consequences. However, further research is needed to examine the potential advantages of these natural additives under several environmental and management circumstances.

Sidebar

Received: 14/1/2022, Accepted:29/5/2022

References

REFERENCES

l ,.Abd El-Hack M. E, El-Saadony M. T, Saad AM, et al. (2022) Essential oils and their nanoemulsions as green alternatives to antibiotics in poultry nutrition: a comprehensive review. Poult Sei 101(2): 101584 https://doi.Org/10.1016/j.psj.2021.101584

2 .Abd El-Hack M. E, El-Saadony M. T, Shafi ME, et al. (2020) Probiotics in poultry feed: A comprehensive review. J Anim Physiol Anim Nutr (Berl) 104(6):1835-1850 https://doi.Org/10.1016/j.psj.2021.101584

3 . Al-Khalaifa H, Al-Nasser A, Al-Surayee T, et al. (2019) Effect of dietary probiotics and prebiotics on the performance of broiler chickens. Poultry Science 98(10):4465-4479 doi:https://doi.org/10.3382/ps/pez282

4 .Alali WQ, Hofacre CL, Mathis GF, and Faltys G. (2013) Effect of essential oil compound on shedding and colonization of Salmonella enterica serovar Heidelberg in broilers. Poultry Science 92(3):836-841 doi:https://doi.org/10.3382/ps.2012-02783

5.Ameen, N. A., N. A.Rahman, , and A. H. Hassan, 2021. Preventative effects of probiotic (miaclost) on experimentally induced hypocalcemic rickets in broiler chicks. Iraqi Journal of Agricultural Sciences, 52(6), 14611474. https://doi.org/10.36103/ijas.v52i6.1487

6.Amerah AM, Jansen van Rensburg C, Plumstead PW, Kromm C, and Dunham S. (2012) Effect of feeding diets containing a probiotic or antibiotic on broiler performance, intestinal mucosa-associated avian pathogenic E. coli and litter water-soluble phosphorus. Journal of Applied Animal Nutrition l:e7 https://doi.Org/10.1017/jan.2013.4

7 .Ayalew H, Zhang H, Wang J, et al. (2022) Potential feed additives as antibiotic alternatives in broiler production. Front Vet Sei 9:916473 https://doi:10.3389/fvets.2022.916473

8 .Aziz, H. I., and Al-Hawezy, D. J. 2021. Effect of probiotics, prebiotics and synbiotic on growth performance of broiler under different stock density. Iraqi Journal of Agricultural Sciences, 52(5), 1126-1138. https://doi.org/10.36103/ijas.v52i5.1451

9.Bahaddad SA, Almalki MHK O A, Alghamdi et al. (2023) Bacillus species as direct-fed microbial antibiotic alternatives for monogastric production. Probiotics Antimicrob Proteins 15(1):1-16 doi: 10.1007/s 12602-022-09909-5

l0.Bilgili SF, Hess JB, Blake JP, Macklin KS, Saenmahayak B, and Sibley JL. (2009) Influence of bedding material on footpad dermatitis in broiler chickens. Journal of Applied Poultry Research 18(3):583-589 doi:https://doi.org/10.3382/japr.2009-00023

11 .Broom L. J. (2017) The sub-inhibitory theory for antibiotic growth promoters. Poult Sei 96(9):3104-3108 https://doi.org/10.3382/ps/pexl 14

12 .Brown M. (2011) Modes of action of probiotics: Recent Developments. J Anim Vet Adv 10(14):1895-1900

13 .Calik A, Omara, II, White MB, Li W, and Dalloul RA. (2019) Effects of dietary direct fed microbial supplementation on performance, intestinal morphology and immune response of broiler chickens challenged with coccidiosis. Front Vet Sei 6:463

14 . Chattopadhyay MK. (2014) Use of antibiotics as feed additives: a burning question. Front Microbiol 5:334 doi: 10.3389/fmicb.2014.00334

15 .Dalloul RA, Lillehoj HS, Shellem TA, and Doerr JA. (2003) Enhanced mucosal immunity against Eimeria acervulina in broilers fed a Lactobacillus-based probiotic. Poult Sei 82(l):62-6 https://doi.org/10.1093/ps/82.L62

16.Dibner JJ, and Richards JD. (2005) Antibiotic growth promoters in agriculture: history and mode of action. Poult Sei 84(4):634-43 https://doi: 10.1093/ps/84.4.634

17.Dorman HJ and Deans SG. (2000) Antimicrobial agents from plants: antibacterial activity of plant volatile oils. J Appl Microbiol 88(2):308-16 https://doi.Org/10.1046/j.13652672.2000.00969.x

18 .Doyle AA, and Stephens JC. (2019) A review of cinnamaldéhyde and its derivatives as antibacterial agents. Fitoterapia 139:104405 https://doi.org/10.1016/j .fitote.2019.104405

19.E1-Shall NA, Shewita RS, ME and Abd ElHack, et al. (2020) Effect of essential oils on the immune response to some viral vaccines in broiler chickens, with special reference to Newcastle disease virus. Poult Sci 99(6):29442954 doi: 10.1016/j.psj.2020.03.008

20 .Ezzat, H. N. 2023. Effect of supplementation fenugreek oil to the diet on the physcological anatomical and histological traits of broilers. Iraqi Journal of Agricultural Sciences, 54(1), 106-113. https://doi.org/10.36103/ijas.v54il.1681

21 .Falcone P, Speranza B, Del Nobile MA, Corbo MR, and Sinigaglia M. (2005) A study on the antimicrobial activity of thymol intended as a natural preservative. J Food Prot 68(8): 1664-70 doi: 10.4315/0362-028x-68.8.1664

22 .Gadde U, Kim WH, Oh ST, and Lillehoj HS. (2017) Alternatives to antibiotics for maximizing growth performance and feed efficiency in poultry: a review. Anim Health Res Rev 18(l):26-45 doi: 10.1017/S1466252316000207

23 .Hernandez F, Madrid J, Garcia V, Orengo J, and Megias MD. (2004) Influence of two plant extracts on broilers performance, digestibility, and digestive organ size. Poult Sei 83(2): 169-74 doi: 10.1093/ps/83.2.169

24.Hu Z, Liu L, Guo F, et al. (2023) Dietary supplemental coated essential oils and organic acids mixture improves growth performance and gut health along with reduces Salmonella load of broiler chickens infected with Salmonella Enteritidis. J Anim Sci Biotechnoi 14(1):95 doi: 10.1186/s40104-023-00889-2

25Jamroz D, Wertelecki T, Houszka M, and Kamel C. (2006) Influence of diet type on the inclusion of plant origin active substances on morphological and histochemical characteristics of the stomach and jejunum walls in chicken. J Anim Physiol Anim Nutr (Berl) 90(5-6):255-68 https://doi.Org/10.l 11 l/j.14390396.2005.00603.x

26 .Jamroz D, Wiliczkiewicz A, Wertelecki T, Orda J, and Skorupińska J. (2005) Use of active substances of plant origin in chicken diets based on maize and locally grown cereals. Br Poult Sei 46(4):485-93 doi: 10.1080/00071660500191056

27 .Jerzsele A, Szeker K, Csizinszky R, et al. (2012) Efficacy of protected sodium butyrate, a protected blend of essential oils, their combination, and Bacillus amyloliquefaciens spore suspension against artificially induced necrotic enteritis in broilers. Poult Sei 91(4):837-43 doi: 10.3382/ps.2011-01853

28 .Lee KW, Li G, Lillehoj HS, et al. (2011) Bacillus subtilis-based direct-fed microbials augment macrophage function in broiler chickens. Res Vet Sei 91(3):e87-91 doi: 10.1016/j. rvsc.201 L0L018

29 .Luciana Kazue O, Marcelo Biondaro Gi, Elis Regina de Moraes G, and Maria Marta L. (2012) Variations on the Efficacy of Probiotics in Poultry. In: Everlon Cid R (ed) Probiotic in Animals. IntechOpen, Rijeka, p Ch. 9

30 .Lutful Kabir SM. (2009) The role of probiotics in the poultry industry. Int J Mol Sei 10(8):3531-46 doi: 10.3390/ijmsl0083531

31 .Mehdi Y, Létourneau-Montminy М-Р, Gaucher M-L, et al. (2018) Use of antibiotics in broiler production: Global impacts and alternatives. Animal Nutrition 4(2):170-178 doi: https://doi.org/10.1016/j .aninu.2018.03.002

32 .Mitsch P, Zitterl-Eglseer K, Köhler В, Gabler C, Losa R, and Zimpernik I. (2004) The effect of two different blends of essential oil components on the proliferation of Clostridium perfringens in the intestines of broiler chickens. Poult Sci 83(4):669-75 doi: 10.1093/ps/83.4.669

33 .Mookiah S, Sieo CC, Ramasamy K, Abdullah N, and Ho YW. (2014) Effects of dietary prebiotics, probiotic and synbiotics on performance, caecal bacterial populations and caecal fermentation concentrations of broiler chickens. J Sci Food Agric 94(2):341-8 doi: 10.1002/jsfa.6365

34 .M'sadeq, S. A. 2019. Effect of dietary supplementation of miaclost on performance and gut morphology in broiler chickens challenged with escherichia coli. Iraqi Journal of Agricultural Sciences, 2(50). https://doi.org/10.36103/ijas.v2i50.650

35 .Mustafa, M. M. 2022. Effect of different levels of oleobiotec on production performance and egg quality traits in Japanese quil. Iraqi Journal of Agricultural Sciences, 53(3),578-583. https://doi.org/10.36103/ijas.v53i3.1566

36 .Nazzaro F, Fratianni F, De Martino L, Coppola R, and De Feo V. (2013) Effect of essential oils on pathogenic bacteria. Pharmaceuticals (Basel) 6(12): 1451-74 doi: 10.3390/ph6121451

37 .Neu HC. (1992) The crisis in antibiotic resistance. Science 257(5073): 1064-73 doi: 10.1126/science.257.5073.1064

38 .Ng SC, Hart AL, Kamm MA, Stagg AJ, and Knight SC. (2008) Mechanisms of Action of Probiotics: Recent Advances. Inflammatory Bowel Diseases 15(2):300-310

39 .Panda AK, Rao SVR, Raju MVLN, and Sharma SR. (2006) Dietary Supplementation of Lactobacillus Sporogenes on Performance and Serum Biochemico - Lipid Profile of Broiler Chickens. The Journal of Poultry Science 43(3):235-240 https://doi.org/10.2141/jpsa.43.235

40 .Park YH, Hamidon F, Rajangan C, et al. (2016) Application of Probiotics for the Production of Safe and High-quality Poultry Meat. Korean J Food Sei Anim Resour 36(5):567-576 doi: 10.5851/kosfa.2016.36.5.567

41 .Patterson JA, and Burkholder KM. (2003) Application of prebiotics and probiotics in poultry production. Poult Sci 82(4):627-31 doi: 10.1093/ps/82.4.627

42 .Peng QY, Li JD, Li Z, Duan ZY, and Wu YP. (2016) Effects of dietary supplementation with oregano essential oil on growth performance, carcass traits and jejunal morphology in broiler chickens. Animal Feed Science and Technology 214:148-153 doi: https://doi.Org/10.1016/j.anifeedsci.2016.02.01 0

43 .Qamar A, Waheed J, Hamza A, et al. (2021) The role of intestinal microbiota in chicken health, intestinal physiology and immunity. J Anim Plant Sci-Рак 31(2):342351 doi: 10.36899/Japs.2021.2.0221

44.Rimini S, Petracci M, and Smith DP. (2014) The use of thyme and orange essential oils blend to improve quality traits of marinated chicken meat. Poult Sci 93(8):2096102 https://doi.org/10.3382/ps.2013-03601

45.SAS Institute, Inc., 2010. SAS OnlineDoc Version 9.1.3, Cary, NC, USA).

46.Schneitz C. (2005) Competitive exclusion in poultry 30 years of research. Food Control 16(8):657-667 doi:https://doi.org/l 0.1016/j .foodcont.2004.06. 002

47.Shini S, Zhang D, Aland RC, et al. (2020) Probiotic Bacillus amyloliquefaciens H57 ameliorates subclinical necrotic enteritis in broiler chicks by maintaining intestinal mucosal integrity and improving feed efficiency. Poult Sci 99(9):4278-4293 doi: 10.1016/j .psj .2020.05.034

48.Singh G, Kapoor IP, Pandey SK, Singh UK, and Singh RK. (2002) Studies on essential oils: part 10; antibacterial activity of volatile oils of some spices. Phytother Res 16(7):680-2 doi:10.1002/ptr.951

49.Spernakova D, Mate D, Rozanska H, and Kovac G. (2007) Effects of dietary rosemary extract and alpha-tocopherol on the performance of chickens, meat quality, and lipid oxidation in meat storaged under chilling conditions. В Vet I Puławy 51(4):585-589

50.Stappen I, Wanner J, Tabanca N, et al. (2014) Chemical composition and biological effects of Artemisia maritima and Artemisia nilagirica essential oils from wild plants of western Himalaya. Planta Med 80(13): 1079-87 doi: 10.1055/s-0034-1382957

51 .Valero M, and Salmerón MC. (2003) Antibacterial activity of 11 essential oils against Bacillus cereus in tyndallized carrot broth. Int J Food Microbiol 85(l-2):73-81 https://d0i.0rg/l 0.1016/SO168-1605(02)004841 1

52.Wu Y, Wang B, Zeng Z, et al. (2019) Effects of probiotics Lactobacillus plantarum 16 and Paenibacillus polymyxa 10 on intestinal barrier function, antioxidative capacity, apoptosis, immune response, and biochemical parameters in broilers. Poult Sei 98(10):5028-5039 doi:10.3382/ps/pez226

53 .Zeng Z, Zhang S, Wang H, and Piao X. (2015) Essential oil and aromatic plants as feed additives in non-ruminant nutrition: a review. Journal of Animal Science and Biotechnology 6(1):7 doi: 10.1186/s40104-015-0004-5