Research Article

Economic Performance of Different Concentrations of Probiotics on Broiler Chickens

Ahmed A. Mohammed1, Madeha H. A. Darwish1, Eman A.A. Negm2, Ayman S. Abdel- Maguid3

1Department of Animal and Poultry Behavior and Management Faculty of Veterinary Medicine, Assuit University-Egypt; 2Department of Animal Physiology, Faculty of Veterinary Medicine, Assuit University- Egypt; 3Department of Agricultural Economic, Faculty of Agriculture, Assuit University- Egypt.

Received | March 16, 2022; Accepted | May 22, 2022; Published | June 30, 2022

*Correspondence | Ayman S Abdel-Maguid, Department of Agricultural Economics, Faculty of Agriculture, Assuit University- Egypt; Email: Safwat_ayman82@yahoo.com

Citation | Mohammed AA, Darwish MHA, Negm EAA, Abdel-Maguid AS (2022). Economic performance of different concentrations of probiotics on broiler chickens. Res J. Vet. Pract. 10(2): 12-18.

DOI | http://dx.doi.org/10.17582/journal.rjvp/2022/10.2.12.18

ISSN | 2308-2798

 

 

Copyright: 2022 by the authors. Licensee ResearchersLinks Ltd, England, UK.

This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

Introduction

Animal feed can be very expensive in livestock production, particularly in poultry production (up to 75%–80% of total costs). Accordingly, in recent years, the use of feed-added substances to increase feed proficiency and reduced costs has been examined (Araujo et al., 2019). Feed-added substances are non-nutritive aggravates that are added to livestock rations to improve the proficiency of feed usage and feed acceptance (Singh et al., 2021).

It is critical for the exceptionally important broiler production division to accomplish the production goals and limit financial misfortunes by guaranteeing the security of broiler meat through controlling and eliminating foodborne microorganisms (Mountzouris et al., 2010).

Probiotics can be utilized to supplant antibiotics because they are dietary enhancements composed of live and non-pathogenic microbial operators that have the advantage of improving wellbeing through intestinal parity (Ayasan, 2013).

Probiotics are singular microorganisms or groups of microorganisms that improve the qualities of the intestinal microflora. Their impact is reflected in the decrease of harm from diseases; they also improve the capacity of the safe production and have a huge effect on the morpho-practical attributes of digestive organs (Okanović et al., 2014). These effects help improve broiler development feed transformation and lead to decreased mortality (Yang, Iji and Choct 2009).

Probiotics gainfully influence the host animal by improving its intestinal parity. They establish gut conditions that stifle destructive microorganisms and favor useful ones, reduce the risk of disease, boost immune function, and increase protection from contamination. In addition to maintaining health, probiotics have been shown to improve the growth performance of poultry (Okanović et al., 2013).

Probiotics are noted for their ability to improve the physical performance of birds, for example, by increasing body weight (BW) and body weight gain (BWG) and by improving feed transformation proportions. Furthermore, they play a significant role in improving the productivity and economic efficiency of poultry farms (Rehman et al., 2020).

A specialist board authorized by the Food and Agriculture Organization (FAO /WHO 2001) characterized probiotics as “live microorganisms” that when regulated in sufficient sums present a medical advantage on the host, improve development loadsof growth, consequently improve economic efficiency.

Ignatova (Ignatova et al., 2009) noted that probiotics dramatically influence BW (p < 0.001), feed intake (FI), and the feed conversion pace of chickens compared with the control group. Probiotics maintain gut health and reduce pathogenic microorganisms and therefore reduce the occurrence of diseases in the poultry themselves (Kampf 2012).

Hence, the point of this study was to determine the impact of added probiotics on the economic aspects of broiler production.

This experiment intended to evaluate the impact of dietary supplementation with probiotics (Lactobacillus delbrueckii) (Probax®) on the economic and productive efficiency of broilers.

MATERIALS AND METHODS

Probiotic

The probiotic L. delbrueckii was used in this study (CLOSTATTM, Kemin, Europe, NV. Herentals, Belgium).

Animals and housing

A total of 120 1-day-old male broiler chicks with comparable normal BW (Ross 708 strain; Mangabad, Assiut, Egypt) were weighed and assigned to 12 floor pens (10 feathered creatures were placed in each 100 × 100 cm floor pen) in a situation-controlled room at the Animal and Poultry Behavior and Management Research Unit, the Faculty of Veterinary Medicine, Assiut University, Egypt. New and dry wood shavings were included at a depth of 10 cm. The rules of Aviagen (Aviagen, 2018) were followed when caring for the broilers.

All procedures and animal handling were approved by the Animal Care and Use Committee of the Faculty of Veterinary Medicine, Assiut University, Egypt.

Dietary treatments

A total number of 120 broilers were used in this study, Broilers are divided into three groups of 40 birds each, housed in 12 floor pens of 10 broilers for every imitate: a normal eating regimen combined with a probiotic concentration of 0 (control), 0.25 (0.25×), and 0.5 (0.5×) g/kg feed, corresponding to groups C, L, and H, respectively. The inclusion of CLOSTATTM dietary medicines depended on the organization’s suggestion, and the dietary treatment time frame lasted from day 1 to day 35, when we arrived at the market weight. The dietary nourishment was provided previously (Mohammed et al., 2018).

Estimation of productive performance

a. Body weight: The chicks were weighed weekly.

b. Feed intake: FI was estimated by regularly providing a known amount of rations at 10:00 AM; at the end of the week, the remaining portion of feed was weighed. From this value, the average daily FI was estimated.

c. Weight gain: Estimated by the differences between two successive weights.

d. Feed conversion: Estimated by dividing the FI/g/bird by weight gain/g/bird according to Wagner (Wagner et al., 1983).

FI (g)/bird/week

FCR= ------------------------------------------

BWG (g)/bird/week

e. Total feed cost: Estimated by multiplying the total FI/g/bird*cost of the rations in kg plus multiplying by the result of the total FI/g/bird*cost of probiotics/g according to (Wagner et al., 1983).

Statistical analysis

The statistical analyses were performed using SPSS software package version 16.0. The data were analyzed using a one-way analysis of variance (ANOVA) followed by a

 

Table 1: Effect of probiotics on productive items of broilers after 7 days

	No.	BW	FI	Feed efficiency	Total feed cost
Control	40	0.16 ± 0.002a	0.09 ± 0.002a	1.8 ± 0.02a	0.55484a
L	40	0.18 ± 0.002b	0.1 ± 0.00002b	1.9 ± 0.02a	0.691566b
H	40	0.19 ± 0.003c	0.09 ± 0.0001a	2.03 ± 0.04b	0.666697b

 

Table 2: Effect of probiotics on productive items of broilers after 28 days

Group	No.	Average BW	Average FI	Average BWG	Feed efficiency	Feed cost
C	40	1.47125 ± 0.03a	1.475575 ± 0.02a	1.314583 ± 0.03a	0.89 ± 0.02a	9.44368a
L	40	1.53125 ± 0.02a	1.548093**±0.01b	1.354583 ± 0.02a	0.88 ± 0.01a	11.32319a
H	40	1.53625*±0.01b	1.584114**±0.01b	1.352917 ± 0.01a	0.85 ± 0.01a	11.58666a

 

Table 3: Effect of probiotics on productive items of broilers after 42 days

Group	No.	Average BW	Average FI	Average BWG	Feed efficiency	Feed cost
C	40	3.49625 ± 0.65a	3.0765 ± 29.3a	3.21 ± 0.07a	1.085514 ± 0.026a	19.6896a
L	40	3.52125 ± 0.39a	3.099125 ± 18.4a	3.34 ± 0.03b	1.079202 ± 0.011a	22.66789b
H	40	3.725* ± 0.37b	3.1625* ± 13.96b	3.48 ± 0.02c	1.119895 ± 0.014a	23.13143b

 

post-hoc lowest significant difference multiple range test for comparisons between the control and experiment groups. All data were represented as the mean ± SE for all experimental and control animals (p < 0.05).

To determine whether there was a significant relationship between BWG and FI of the three different groups at the end of the experiment, the data were analyzed using a regression analysis and an ANOVA (SAS 2002).

Results

The results after seven days of treatment are presented in Table 1. There was a significant increase (p < 0.05) in BW for all groups compared with the baseline, although FI only displayed a significant increase in L group compared with the control group (p < 0.05). Feed efficiency displayed a significant increase in the H group (p < 0.05) compared with both L and control groups; moreover, there was a significant increase in the feed cost (p < 0.05) between both L and H groups and the control group.

Table 2 showed that there was a significant increase (p < 0.05) in BW after 28 days between group H and control group, in the meantime, FI results exhibited a significant increase (p < 0.05) between the control and either L and H groups. There were no significant differences between the three groups for BWG, feed efficiency, or cost.

The results in Table 3 showed only significant increases (p < 0.05) in the final BW and FI after 42 days of the treated group (H) only, compare with the pair groups (L) and control. The control group had the lowest BW. The final BWG results displayed a significant increase (p < 0.05) of the treated groups (H and L) among the three groups. Feed efficiency did not differ significantly between the groups; however, feed cost increased significantly between both the L and H treated groups and the control group.

Figure 1 shows the regression between BWG and FI in the control group. The coefficient of determination (R2) from this analysis indicates that the responsibility ratio of the independent factor (FI) associated with changes in the dependent factor (BWG) was 6%, which means there was a weak effect of the independent factor (FI) on the dependent factor (BWG).

Figure 2 shows the regression between BWG and FI in the L group. R2 from this analysis indicates that the responsibility ratio of the independent factor (FI) associated with changes in the dependent factor (BWG) was 6%, which means there was a weak effect of the independent factor (FI) on the dependent factor (BWG).

Figure 3 shows the regression between BWG and FI in the H group. R2 from this analysis indicates that the responsibility ratio of the independent factor (FI) associated with changes in the dependent factor (BWG) was 10%, which means there was a positive effect of the independent factor (FI) on the dependent factor (BWG).

Discussion

One of the goals of the present study was to clarify the effects of dietary supplementation with probiotics and their different concentrations on growth. After the first week, a probiotics effect appeared in the two treated groups (L and H), which was displayed as a significant increase in BW than the control group, with that the L group showing the highest significant FI. This disagreed with the results of. Mohamed et al. (2014), who found that during the first week of treatment, the control group did not differ significantly from the two probiotics-treated groups. Similarly, another study observed that feed intake didn’t changed by the additon of probiotics (Sohail et al., 2012). Otherwise, Hamasalim (2016), certained such the extention of probiotic, caused a harmonious of GIT microbiota which is neccessary for the intial growth of the intestine which leads to superior feed intake in broilers throughout the begning phase.

Conversely, after 28 days, the effect of high levels of probiotics (group H) demonstrated a significant increase of BW in group H compared with group L and the control group; meanwhile, both treated groups (L and H) exhibited a significant increase in FI compared with the control group. These results were aligned with Abdel-Raheem and Abd-Allah, (2011), stated that the extention by probiotics shorted the time of stomch emptying, which leads to superior feed intake. Also these findings might be a result of the probiotics action on the intestinal microflora, which improve the digestibility and absorbability and take advantage of different supplements in the gastro intestinal tract (Yu et al., 2022). Dietary probiotics intiate the growth of valuable bacteria by yielding various metabolites and thus meliorate the gut microecological atmosphere and the activity of outward chemicals on redressing digestibility of the supplements and diminishing of phosphorous and nitrogen (Attia et al., 2013; Sun et al., 2019; Robinson et al., 2020).

The data presented after 42 days showed significant increases in BW and FI between group H compared with both group L and the control group. These end results in straight with Sohail et al., 2012 who fixed that the weight gain was enlarged with eleveted levels of probiotics. Similiarly (Waititu et al., 2014; Qorbanpour et al., 2018; Jha et al., 2020); declared that addition of probiotics cause significantly increase of BW, BWG and feed efficiency in broilers.

Abetterment in weight gain might be related with such dietary probiotics have been introduced to preserve the balance of the intestinal flora of animals, prevent digestive tract diseases, improve feed digestibility, contribute to increased nutrient use, and cause better zootechnical output in animals (Rehman et al., 2020).

These findings agree with those of Rehman et al. (2020), Kannan et al. (2017), and Kalavathy et al. (2008); who found that normal BW was improved in the group that was fed a supplemented diet with probiotics compared with that of the control group. Moreover, these discoveries are similar to those obtained by Nayebpor et al. (2007), who found that feeding broiler chickens bolstered microbial probiotics significantly (p < 0.05) increased their BW. The probiotic (L. acidophilus)-treated groups in both Ross and Hubbard Cobb given the most elevated income in net benefit compared with Cobb. This was a result of the increases in BW, BWG, and feed conversion ratio and the reduction in the mortality rate.

These findings are supported by other results showing that broiler chicks fed the control diet supplemented with yeast and probiotic-containing bacteria (BioGaurd) significantly increased weight gain weekly, during the second week, and during all weeks of the experiment until the last week, in which the final weight gain was significantly higher in the BioGaurd-fed broilers (Mohamed et al., 2014). However, our results disagreed with those of Mohamed et al. 2014 because the probiotics feeding within each level significantly affected weight gain during the first week in our study. But, although the addition of probiotics to the feed rations did not result in significant differences between the three groups in weight gain at the middle of the experiment (28 days), the final total weight gain was significantly higher in both probiotics-treated groups (L and H) compared with the control group. Meanwhile, the H group displayed the highest BWG compared with the other treated group.

The feed cost for the production of the group H broilers was significantly higher (23.13 L.E/bird) than that of the control group (19.69 L.E/bird). The feed cost of group L (22.67 L.E/bird) was also significantly higher than the control group. Moreover, the benefit of the group H broilers was better than that of group L because the total return per average weight of the chick was significantly higher in group H (3.725* ± 0.37 vs. 3.52125 ± 0.39, respectively). This finding agrees with those of Santin et al. (Santin et al., 2001) and Panda (Panda et al., 2006) who found significant increases (p < 0.05) in the net income value of groups supplemented with probiotics compared with the control groups; thus, the probiotics improved the financial proficiency of broiler production.

The obtained results showed that although the feed additives significantly increased the total feed cost compared with the control group, the H group had a higher total return (3.48 ± 0.02) compared with the L group (3.34 ± 0.03), and both were better than the control group (3.21 ± 0.07). This agrees with the findings of Seifi (2013) who discovered that during the first and second weeks, feeding commercial broiler ration; feed conversion ratio was better in Arbor acres broilers. With regard to the effect of probiotics, the control group did not differ significantly from the two treated groups during the first week, while the use of yeast and probiotics-containing bacteria (BioGaurd) improved the overall feed conversion ratio (1.69 ± 0.03) compared with the bacterial probiotic plus enzyme mixture (Micro-BACLA) (1.78 ± 0.01) and the control group (1.79 ± 0.01). This result could be attributed to the action of microbial floras on the alimentary tract, which have considerable effects on the health and performance of boiler chickens (Wang Yanbo and Qing Gu 2010; Alkhalf, Alhaj and Al-homidan 2010).The addition of a low level of probiotics did not have a significant effect on BW after 28 days or at the end of the experiment after 42 days. Conversely, the addition of a high level of probiotics increased BW after 28 days and at the end of the experiment.

Using two concentrations of probiotics as feed additives resulted in a nearly significant increase of BW and BWG in the high concentration group compared with the low concentration group at the end of the experiment. The results showed that each treated group had a significantly increased total feed cost compared with the control group. However, the increase in the total cost was compensated by a significantly higher increase in the total return. This result agreed with those of (Panda et al., 2006) and (Bonsu et al., 2012) who found that using probiotics in broiler chickens led to increased economic profit margins due to their positive effect on performance.

There was a weak effect of the independent factor (FI) on the dependent factor (BWG) in the C and L groups (Figs. 1 and 2).

There was a positive relationship between BWG and FI in the H group; furthermore, the largest regression and the highest R2 appeared in the H group results (Figure 3), which indicates that the increase in the percentage of high probiotics level (group H) resulted in an increase in liability percentage of probiotic for changes in the event (the effect of the independent factor (FI) on the dependent factor (BWG)).

We measured the effect of two different concentrations of probiotics on meat yield in broiler chickens and found that when probiotics were added at a concentration of 0.25, meat yield increased at an insignificant rate, but when added at a concentration of 0.5, it increased at a significant rate.

In terms of the total variable cost (feed cost), compared with the control group, there was an increase in the cost and in the meat yield for the two treated groups (L and H) at rates of 3.34 ± 0.03 and 3.48 ± 0.02, respectively. The highest concentration treated group (H) had the highest meat yield (3.48 ± 0.02), which exceeds the rate of increase in cost (23.13). According to the poultry stock, the price of broilers in kg at that time was 24 LE/kg, indicating a value increase of approximately 83 L.E, which reflects the increased economic feasibility from adding probiotics at a higher concentration compared with a low concentration.

Conclusion

This study suggests that using a probiotic feed additive (L. delbrueckii) at high concentrations can significantly improve the economic and productive efficiency of poultry farm although it constitute small cost from the variable costs of poultry output.

acknowledgements

Faculty of Veterinary medicine , Assuit University, Egypt.

conflict of interest

The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

novelty statement

Economic view of broiler breeding with different supplement of probiotics.

authors contribution

Ahmed A. Mohammed: Conceptualization, Methodology. Ayman S. Abdel- Maguid: Data curation, Analysis, Software, Writing. Eman A A Negm : Reviewing. Madeh HA Darwish : Supervision.

References

Abdel-Raheem S.M., Abd-Allah S.M.S. (2011). The effect of the single or combined addition of mannanoligosaccharide and probiotics on performance and slaughter characteristics of broilers. Int. J. Poult. Sci., 10: 854-862. https://scialert.net/abstract/?doi=ijps.2011.854.862 https://doi.org/10.3923/ijps.2011.854.862

Alkhalf A., M. Alhaj, I. Al-homidan (2010). Influence of probiotic supplementation on blood parameters and growth performance in broiler chickens. Saudi. J. Biol. Sci. 17:219–225. Available at: https://www.sciencedirect.com/science/article/pii/S1319562X10000434 [Accessed December 21, 2020]. https://doi.org/10.1016/j.sjbs.2010.04.005

Araujo, RGAC et al. (2019). “Performance And Economic Viability Of Broiler Chickens Fed With Probiotic And Organic Acids In An Attempt To Replace Growth-Promoting Antibiotics.” Brazilian J. Poult. Sci., 21: 02. Epub 29 July 2019. ISSN 1806-9061. https://doi.org/10.1590/1806-9061-2018-0912.

Attia YA, Abd HE, Ismaiel AM, El-Nagar A. (2013). “The detoxication of nitrate by two antioxidants or a probiotic, and the effects on blood and seminal plasma profiles and reproductive function of New Zealand white rabbit bucks.” Animal.; 7(4):591–601. https://doi.org/10.1017/S1751731112002054

Aviagen (2018). Ross broiler management handbook. USA: Aviagen Inc., Huntsville, AL.

Ayasan T. (2013). Effects of dietary inclusion of protexin (probiotic) on hatchability of Japanese quails. Indian J. Anim. Sci. 83(1):78–81. Available at: https://www.mendeley.com/catalogue/663b59a7-9527-3b78-aeaf-b6a553a6fa37/?utm_source=desktop

utm_medium=1.19.4&utm_campaign=open_catalog&userDocumentId=%7B5b09f412-1d89-4deb-9ddd-4c241c9bd91f%7D.

Bonsu F.R.K., A. Donkoh S.A.B. Osei, D. Okai J. Baah (2012). Effect of direct-fed microbial and antibiotics supplementation on the health status and growth performance of broiler chickens under hot humid environmental conditions. Int. J. Livestock. Prod. 3(6):56–66.

FAO/WHO Guidelines for the evaluation of probiotics in food. Report of a joint FAO/WHO working group on drafting guidelines for the evaluation of probiotics in food. London, Ontario, Canada (2002). [Cited April 30 and May 1, 2002]. Accessed Oct. 2020 (2002) http://www.who.int/foodsafety/fs_managem ent/en/probiotic_ guidelines.pdf

Hamasalim H.J. (2016). “Symbiotic as feed additives relating to animal health and performance.” Adv. Microb., 6, 288-302. https://doi.org/10.4236/aim.2016.64028

Ignatova M., V. Sredkova, V. Marasheva (2009). “Effect of dietary inclusion of probiotic on chickens performance and some blood indices.” Biotechnol. Anim. Husband. 25(6):1079–1085. Available at: http://scindeks.ceon.rs/article.aspx?artid=1450-91560906079I [Accessed December 21, 2020].

Jha R, Das R, Oak S, Mishra P (2020). “Probiotics (direct-fed microbials) in poultry nutrition and their effects on nutrient utilization, growth and laying performance, and gut health: a systematic review.” Animals (Basel);10(10):1863. https://doi.org/10.3390/ani10101863

Kalavathy R., N. Abdullah S. Jalaludin C.M.V.L. Wong, Y.W. Ho. (2008). “Effect of Lactobacillus cultures and oxytetracycline on the growth performance and serum lipids of chickens.” Int. J. Poult. Sci. 7(4):385–389. https://doi.org/10.3923/ijps.2008.385.389

Kampf D (2012). “Probiotics in Poultry nutrition.” DGS-Maga (Magazin für Geflüge lwirtschaft und Schweine produktion). 64(14):25–28.

Kannan D., K. Viswanathan, B. Mohan, TANUVAS (2017). “The Effect Of Feeding Virginiamycin and Lactobacillus Sporogenes On Broiler Production Performance Characters.” Available at: https://krishikosh.egranth.ac.in/handle/1/5810145228 [Accessed December 21, 2020].

Mohamed N., A. ElTahawy M. Edel, S. Zakaria, U. Mahrous (2014). “Effect of Probiotic Supplementation on Productive Performance and Economic Efficiency of Arbor Acres and Cobb300 Broilers.” Alexandria Journal Vet. Sci. 43(1):65. https://doi.org/10.5455/ajvs.164050

Mohammed A.A., J.A. Jacobs, G.R. Murugesan, H.W. Cheng (2018). Animal well-being and behavior: Effect of dietary synbiotic supplement on behavioral patterns and growth performance of broiler chickens reared under heat stress. Poult. Sci. 97(4):1101–1108. Available at: https://pubmed.ncbi.nlm.nih.gov/29340655/ [Accessed December 21, 2020]. https://doi.org/10.3382/ps/pex421

Mountzouris K.C., P. Tsitrsikos I. Palamidi A. Arvaniti M. Mohnl G. Schatzmayr, K. Fegeros (2010). “Effects of probiotic inclusion levels in broiler nutrition on growth performance, nutrient digestibility, plasma immunoglobulins, and cecal microflora composition.” Poult. Sci. 89(1):58–67. Available at: https://pubmed.ncbi.nlm.nih.gov/20008803/ [Accessed December 21, 2020]. https://doi.org/10.3382/ps.2009-00308

Nayebpor M., P. Farhomand, A. Hashemi (2007). Effect of different levels of direct fed microbial (Primalac) on growth performance and humeral immune response in broiler chickens. J. Anim. Vet. Adv. 3(2):1308 – 1313.

Okanović, D.G., N.R. Džinić, D.R. Karović, T.A. Tasić, V.A. Radović, S.S. Filipović, and P.M. Ikonić (2013). “The effects of mineral adsorbents added to broilers diet on breast meat quality.” Acta Periodica Technolog. 44:95–102. https://doi.org/10.2298/APT1344095O

Okanović Đorđe, Colovic Radmilo, Tasić Tatjana, V. Zekić & Ikonić Predrag (2014). The impact of probiotics additives added into diet on economic results of broilers production.” J. Hygien. Engineer. Design (JHED). 7: 148-151. https://keypublishing.org/jhed/wp-content/uploads/2020/07/02.-Djordje-Okanovi%C4%87.pdf

Panda A.K., S. V. Rama Rao, M.V.L.N. Raju, S.R. Sharma (2006). “Dietary Supplementation of Lactobacillus Sporogenes on Performance and Serum Biochemico - Lipid Profile of Broiler Chickens. J. Poult. Sci. 43(3):235–240. https://doi.org/10.2141/jpsa.43.235

Qorbanpour M, Fahim T, Javandel F, Nosrati M, Paz E, Seidavi A, Ragni M, Laudadio V, Tufarelli V. (2018). Effect of dietary ginger (Zingiber officinale Roscoe) and multi-strain probiotic on growth and carcass traits. Blood biochemistry, immune responses and intestinal microflora in broiler chickens. Animals. (Basel).8(7):117. https://doi.org/10.3390/ani8070117

Rehman A., M. Arif, N. Sajjad, M.Q. Al-Ghadi, M. Alagawany, M.E. Abd El-Hack, A.R. Alhimaidi, S.S. Elnesr, B.O. Almutairi, R.A. Amran, E.O.S. Hussein, A.A. Swelum (2020).Dietary effect of probiotics and prebiotics on broiler performance, carcass, and immunity. Poult. Sci. 99: 12, 6946-6953. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7705049/. https://doi.org/10.1016/j.psj.2020.09.043

Robinson K, Xiao YP, Johnson TJ, Chen BY, Yang Q, Lyu WT, Wang J, Fansler N, Becker S, Liu J, Yang H, Zhang GL. (2020). Chicken intestinal mycobiome: initial characterization and its response to bacitracin methylene disalicylate. Appl. Environ. Microbiol.86(13):e00304-20. https://doi.org/10.1128/AEM.00304-20

Santin, E., A. Maiorka, M. Macari, M. Grecco, J.C. Sanchez, T.M. Okada, and A.M. Myasaka. (2001). “Performance and intestinal mucosa development of broiler chickens fed diets containing Saccharomyces cerevisiae cell wall.” J. Appl. Poult. Res.. 10(3):236–244. https://doi.org/10.1093/japr/10.3.236

SAS. (2002). Statistical Analysis System.Users Guide StatisticsAs. Institute Cary, North Carolina.

Seifi S. (2013). An investigation of the effects of using an enzyme-probiotic combination on broilers performance. Iranian. J. Vet. Med. IJVM. 7(4): 299-304. https://www.sid.ir/en/journal/ViewPaper.aspx?id=409136

Singh D, Sheela C, Monika K, Manju (2021). Novel Use of Modern Feed Additives In Poultry Farming. Poult. Punch Magazine. https://thepoultrypunch.com/2021/02/novel-use-of-modern-feed-additives-in-poultry-farming/

Sohail MU, Hume ME, Byrd JA, Nisbet DJ, Ijaz A, Sohail A, Shabbir MZ, Rehman H. (2012). Effect of supplementation of prebiotic mannan-oligosaccharides and probiotic mixture on growth performance of broilers subjected to chronic heat stress. Poult. Sci. 91(9):2235–2240. https://doi.org/10.3382/ps.2012-02182

Sun P, Zhang W, Miao Y, Chen Z. (2019). Letter: meta-analysis of prebiotics, probiotics, synbiotics and antibiotics in IBS. Aliment. Pharmacol. Therrapeut. 49(9):1253–1254. https://doi.org/10.1111/apt.15230

Yang Y., P.A. Iji, M. Choct (2009). Dietary modulation of gut microflora in broiler chickens: A review of the role of six kinds of alternatives to in-feed antibiotics.” World’s Poult. Sci. Journal. 65(1):97–114. Available at: https://www.tandfonline.com/doi/abs/10.1017/S0043933909000087 [Accessed December 21, 2020]. https://doi.org/10.1017/S0043933909000087

Yu Yang, Li Qing, Zeng Xinfu, Xu Yinglei, Jin Kan, Liu Jinsong, Cao Guangtian (2022) Effects of Probiotics on the Growth Performance, Antioxidant Functions, Immune Responses, and Caecal Microbiota of Broilers Challenged by Lipopolysaccharide. Front. Vet. Sci. 9. URL=https://www.frontiersin.org/article/10.3389/fvets.2022.846649

Wagner D.D., R.D. Furrow B.D. Bradley (1983). Subchronic Toxicity of Monensin in Broiler Chickens. Vet. Pathol. 20(3):353–359. Available at: https://pubmed.ncbi.nlm.nih.gov/6879957/ [Accessed December 21, 2020]. https://doi.org/10.1177/030098588302000311

Waititu SM, Yitbarek A, Matini E, Echeverry H, Kiarie E, Rodriguez-Lecompte JC, Nyachoti CM. (2014). Effect of supplementing direct-fed microbials on broiler performance, nutrient digestibilities, and immune responses. Poult. Sci. 93(3):625–635. https://doi.org/10.3382/ps.2013-03575

Wang Y, Qing G (2010). “Effect of probiotic on growth performance and digestive enzyme activity of Arbor Acres broilers.” Res. Vet. Sci., 89:163–167. Available at: https://www.sciencedirect.com/science/article/pii/S0034528810000834. https://doi.org/10.1016/j.rvsc.2010.03.009