Research Article
1Institute of Animal Breeding and Biodiversity Conservation, Laboratory for Organic Production of Food of Animal Origin, University of Life Sciences in Lublin, Akademicka 13, 20-950 Lublin, Poland
2Department of Ruminant Science, West Pomeranian University of Technology, Klemensa Janickiego 29, 71-270 Szczecin, Poland
Abstract. The study was aimed to assess the rearing parameters in Ross 308 broiler chickens depending on the intensity of infection with Eimeria protozoa. Two flocks were included in the analysis. One was found to be free from coccidiosis (healthy flock HF) and the other was classified as infected flock (IF). The collected data included the age of the chickens, losses (including falls and culls), body weight, weight gains, and daily feed intake. Additionally, the mean feed intake per kg body weight was estimated and the European Production Efficiency Factor (EPEF) was calculated. The study demonstrated that the presence of Eimeria parasites in the rearing environment of broiler chickens had an impact on the rearing performance by increasing the demand for feed and the percentage of falls and culls during the rearing period, in comparison with chickens from the coccidiosis-free flock. Although they consumed higher amounts of feed, the coccidia-infected chickens were characterized by substantially lower weight gain values. The EPEF value on rearing day 42 in the Eimeria-infected broiler flock was by 103.66 lower than that calculated in the healthy flock.
Keywords: broiler chickens, coccidia, feed intake, EPEF, rearing performance
Among the various determinants of the rearing performance and broiler chicken welfare, an important role is played by microbiological contamination in the rearing environment of these birds [Burbarelli et al. 2015Burbarelli, M.F.C., Merseguel C.E.B., Ribeiro, P.A.P., Lelis, K.D., Polycarpo, G.V. Carão, A.C.P., Bordin, R.A. Fernandes, A.M., Souza, R.L.M., Moro, M.E.G., Albuquerque, R. (2015). The effects of two different cleaning and disinfection programs on broiler performance and microbiological status of broiler houses. Brazil. J. Poultry Sci., 17(4), 575–580. https://doi.org/10.1590/1516-635X1704575-580, Jiang et al. 2018aJiang, L., Li, M., Tang, J., Zhao, X., Zhang, J., Zhu, H., Yu, X., Li, Y., Feng, T., Zhang, X. (2018a). Effect of different disinfectants on bacterial aerosol diversity in poultry houses. Front. Microbiol., 9, No 2113. https://doi.org/10.3389/fmicb.2018.02113]. Birds and their droppings, fodder, and bedding are the main sources of microorganisms [Lonc and Plewa 2010Lonc, E., Plewa, K. (2010). Microbiological air contamination in poultry houses. Polish J. Environ. Stud., 19(1), 15–19. https://doi.org/10.1007/978-3-540-76435-9\_294, Wójcik et al. 2010Wójcik, A., Chorąży, Ł., Mituniewicz, T., Witkowska, D., Iwańczuk-Czernik, K., Sowińska, J. (2010). Microbial air contamination in poultry houses in the summer and winter. Pol. J. Environ. Stud. 19(5), 1045–1050. Google Scholar]. The amount and type of microorganisms present in poultry facilities depend on the hygienic conditions, air temperature and humidity, ventilation efficiency, quality and physicochemical properties of the bedding, and flock health status [Witkowska et al. 2010Witkowska, D., Chorąży, Ł., Mituniewicz, T., Makowski, W. (2010). Zanieczyszczenia mikrobiologiczne ściółki i powietrza podczas odchowu kurcząt brojlerów [Microbiological contamination of litter and air during rearing of broiler chickens]. Woda–Środowisko–Obszary Wiejskie, 10, 2(30), 201–210 [in Polish]. Google Scholar, Bombik et al. 2011Bombik, T., Biesiada-Drzazga, B., Bombik, E., Frankowska, A. (2011). The influence of temperature and humidity conditions on productivity and welfare of broiler chickens. Acta Sci. Pol. Zootechnica, 10(4), 23–30. Google Scholar, Lewandowska 2012Lewandowska, O. (2012). Główne przyczyny występowania biegunek u drobiu [The main causes of diarrhea in poultry]. Magazyn Hodowcy, 2, 32–37 [in Polish]. Google Scholar, Stuper-Szablewska et al. 2018Stuper-Szablewska, K., Szablewski, T., Nowaczewski, S., Gornowicz, E. (2018). Zagrożenia chemiczne i mikrobiologiczne związane z hodowlą drobiu [Chemical and microbiological hazards related to poultry farming]. Med. Środ., 21(4), 53–63 [in Polish]. Google Scholar]. 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Analyses of aerosol concentrations and bacterial community structures for closed cage broiler houses at different broiler growth stages in winter. J. Food Prot., 81(9), 1557–1564. https://doi.org/10.4315/0362-028X.JFP-17-524]. As shown in many studies [Rathgeber et al. 2009Rathgeber, B.M., Thompson, K.L., Ronalds, C.M., Budgell, K.L. (2009). Microbiological evaluation of poultry house wall materials and industrial cleaning agents. J. Appl. Poult. Res., 18(3), 579–582. https://doi.org/10.3382/japr.2009-00017, Świątkiewicz et al. 2009Świątkiewicz, S., Arczewska, A., Koreleski, J. (2009). Niektóre składniki pokarmowe a przebieg kokcydiozy u drobiu [Effect of some nutrients on coccidiosis in poultry]. Med. Weter., 65(9), 584–587 [in Polish]. Google Scholar, Lewandowska 2012Lewandowska, O. (2012). Główne przyczyny występowania biegunek u drobiu [The main causes of diarrhea in poultry]. Magazyn Hodowcy, 2, 32–37 [in Polish]. Google Scholar, Moraes et al. 2015Moraes, J.C., França, M., Sartor, A.A., Bellato, V., de Moura, A.B., de Lourdes Borba Magalhães, M., de Souza, A.P., Miletti, L.C. (2015). Prevalence of Eimeria spp in broilers by multiplex PCR in the southern region of Brazil on two hundred and fifty farms. Avian Dis., 59, 277–281. https://doi.org/10.1637/10989-112014-Reg, Blake et al. 2020Blake, D.P., Knox, J., Dehaeck, B., Huntington, B., Rathinam, T., Ravipati, V., Ayoade, S., Gilbert, W., Adebambo, A.O., Jatau, I.D., Raman, M., Parker, D., Rushton, J., Tomley, F.M. (2020). Re-calculating the cost of coccidiosis in chickens. Vet. Res., 51, No115. https://doi.org/10.1186/s13567-020-00837-2], intestinal Eimeria protozoa, which attack intestinal cells in poultry and cause coccidiosis, are one of the most serious problems in modern poultry production due to their relatively common presence in the environment of poultry rearing and maintenance.
Eimeria tenella, E. acervulina, E. praecox, E. necatrix, E. maxima, and E. brunetti are coccidia species that commonly infect poultry [Konarkowski 2007Konarkowski, A. (2007). Problemy z chorobami kurcząt brojlerów w Unii Europejskiej [Problems with diseases of broiler chickens in the European Union]. Polskie Drob., XIV(2), 49–52 [in Polish]. Google Scholar, Haug et al. 2008Haug, A., Gjevre, A-G., Skjerve, E., Kaldhusdal, M. (2008). A survey of the economic impact of subclinical Eimeria infections in broiler chickens in Norway. Avian Path., 37(3), 333–341. https://doi.org/10.1080/03079450802050705, Pirus 2008Pirus, T. (2008). Profilaktyka kokcydiozy u drobiu [Prophylaxis of coccidiosis in poultry]. Hod. Drobiu, 6–7, 42–48 [in Polish]. Google Scholar, Moraes et al. 2015Moraes, J.C., França, M., Sartor, A.A., Bellato, V., de Moura, A.B., de Lourdes Borba Magalhães, M., de Souza, A.P., Miletti, L.C. (2015). Prevalence of Eimeria spp in broilers by multiplex PCR in the southern region of Brazil on two hundred and fifty farms. Avian Dis., 59, 277–281. https://doi.org/10.1637/10989-112014-Reg]. They are characterized by highly varied pathogenicity [Hafez 2008Hafez, M.H. (2008). Poultry coccidiosis: prevention and control approaches. Arch. Geflügelk., 72(1), 2–7. Google Scholar].
Low-intensity coccidial infection does not produce clinical symptoms in birds [Świątkiewicz et al. 2009Świątkiewicz, S., Arczewska, A., Koreleski, J. (2009). Niektóre składniki pokarmowe a przebieg kokcydiozy u drobiu [Effect of some nutrients on coccidiosis in poultry]. Med. Weter., 65(9), 584–587 [in Polish]. Google Scholar]; nevertheless, it causes weaker absorption of nutrients with usually worse feed conversion rates, lower uniformity of the flock, poor growth, weight loss, and possibly falls [Hafez 2008Hafez, M.H. (2008). Poultry coccidiosis: prevention and control approaches. Arch. Geflügelk., 72(1), 2–7. Google Scholar, Świątkiewicz et al. 2009Świątkiewicz, S., Arczewska, A., Koreleski, J. (2009). Niektóre składniki pokarmowe a przebieg kokcydiozy u drobiu [Effect of some nutrients on coccidiosis in poultry]. Med. Weter., 65(9), 584–587 [in Polish]. Google Scholar, Lewandowska 2012Lewandowska, O. (2012). Główne przyczyny występowania biegunek u drobiu [The main causes of diarrhea in poultry]. Magazyn Hodowcy, 2, 32–37 [in Polish]. Google Scholar]. The clinical form of the disease is characterized by enteritis, diarrhea, and increased mortality [Getachew et al. 2008Getachew, G., Getachew, T., Dorchies, P. (2008). Study on poultry coccidiosis in Tiyo District, Arsi Zone, Ethiopia. Inter. J. Poult. Sci., 7, 251–256. https://doi.org/10.3923/ijps.2008.251.256]. Coccidia can also damage the immune system and make poultry more susceptible to other pathogens, e.g. Clostridium, Salmonella, and E. coli [McDougald and Fitz-Coy 2012McDougald, L.R., Fitz-Coy, S.H. (2012). Coccidiosis, in: Diseases of poultry, 12th Edition, eds Y.M. Saif, A.M. Fadly, J.R. Glisson, L.R. McDougald, L.K. Nolan, D.E. Swayne. Blackwell Publishing Ltd, Oxford, 1068–1085. Google Scholar].
Poultry flocks that are completely free from coccidiosis are very rarely found [Haug et al. 2008Haug, A., Gjevre, A-G., Skjerve, E., Kaldhusdal, M. (2008). A survey of the economic impact of subclinical Eimeria infections in broiler chickens in Norway. Avian Path., 37(3), 333–341. https://doi.org/10.1080/03079450802050705]. The course of the disease in infected flocks depends on the Eimeria species and their pathogenicity, the number of invasive coccidian oocysts present in the environment and ingested by birds, the age of the birds, and the level of potential resistance to coccidiosis [Mazanowski 2011Mazanowski, A. (2011). Nowoczesna produkcja kurcząt brojlerów [Modern production of broiler chickens]. Wyd. ProAgricola, Gietrzwałd, 245 [in Polish]. Google Scholar, Chapman 2014Chapman, H.D. (2014). Milestones in avian coccidiosis research: a review. Poult. Sci., 93(3), 501–511. https://doi.org/10.3382/ps.2013-03634, Gaweł et al. 2015Gaweł, A., Bobusia, K., Bobrek K. (2015). Identyfikacja gatunków Eimeria spp występujących u kur i kurcząt brojlerów na terenie Polski [Identification of Eimeria spp occurring in hens and broiler chickens in Poland]. Med. Weter., 71(6), 382–385 [in Polish]. Google Scholar]. The risk of coccidiosis increases with the increase in bird density per unit area, at temperatures exceeding 23℃, and at high humidity of the bedding [Hafez 2008Hafez, M.H. (2008). Poultry coccidiosis: prevention and control approaches. Arch. Geflügelk., 72(1), 2–7. Google Scholar].
Coccidiosis is regarded as one of the most severe health and financial problems contributing to huge global losses in poultry farming. As reported by Michalski [2007]Michalski, M.M. (2007). Straty ekonomiczne powodowane inwazjami pasożytniczymi u zwierząt i sposoby ich wyceny [Economic losses caused by parasite invasions in animals and methods of their evaluation]. Med. Weter., 63(6), 643–647 [in Polish]. Google Scholar, there are direct losses resulting from the falls of sick birds and indirect ones, i.e. poor weight gain, uneven growth, low feed conversion rates, and unfavorable carcass pigmentation. Bera et al. [2010]Bera, A.K., Bhattacharya, D., Pan, D., Dhara, A., Kumar, S., Das, S.K. (2010). Evaluation of economic losses due to coccidiosis in poultry industry in India. Agric. Econ. Res. Rev., 23, 91–96. Google Scholar showed that 68.08% of the annual losses related to coccidiosis in India resulted from reduced body weight gain in broilers and 22.7% were the costs of the increased Feed Conversion Ratio (FCR). EU estimates indicate that the total cost of coccidiosis incurred by producers is approx. 0.05 EUR/broiler, with 70–80% resulting from subclinical coccidiosis [Szeleszczuk et al. 2016Szeleszczuk, P., Doner, S., Nerc, J. (2016). Wstępna próba oceny strat finansowych spowodowanych kokcydiozą w produkcji kurcząt brojlerów, w: I Międzynarodowa Konferencja Techniczna EIMERIANA AVIA. Kokcydioza drobiu – aktualne wyzwania AD 2016, red. P. Szeleszczuk, A. Gaweł [A preliminary attempt to assess the financial losses caused by coccidiosis in the production of broiler chickens, in: I International Technical Conference EIMERIANA AVIA. Poultry coccidiosis – current challenges AD 2016, eds. P. Szeleszczuk, A. Gaweł]. Wrocław 26–27.02.2016, 89–98 [in Polish]. Google Scholar]. As shown by Blake et al. [2020]Blake, D.P., Knox, J., Dehaeck, B., Huntington, B., Rathinam, T., Ravipati, V., Ayoade, S., Gilbert, W., Adebambo, A.O., Jatau, I.D., Raman, M., Parker, D., Rushton, J., Tomley, F.M. (2020). Re-calculating the cost of coccidiosis in chickens. Vet. Res., 51, No115. https://doi.org/10.1186/s13567-020-00837-2, the global cost of coccidiosis in poultry flocks is 10.4 billion GBP, i.e. 0.16 GBP per produced broiler.
The aim of the study was to evaluate the parameters of broiler chicken rearing depending on the intensity of infection with Eimeria protozoa.
The study involved Ross 308 broiler chickens. The birds, originating from the Poultry Hatchery in Mazowieckie Province, were reared on a chicken farm located in the Lublin region. The chickens were maintained in a bedding system in buildings with an area of approx. 2340 m2. They received fodder produced from components available on the farm (wheat, corn, triticale) and from purchased ingredients (soybean meal, soybean oil, premixes, fodder chalk, rock salt, acidifier, and phosphorus). The farm was under constant veterinary supervision. Microbiological and parasitological tests were carried out systematically to detect diseases in the poultry flocks (e.g. salmonellosis, coccidiosis, reovirosis) and as part of disease prophylaxis.
The diagnostics of coccidiosis on the analyzed farm consisted in determination of the infection intensity. The examinations were performed on the 23rd day of chickens’ life. For the analysis, a representative sample of feces weighing approximately 0.5 kg was collected from the entire surface of the henhouse and placed in a plastic bag. The sample was sent to a certified laboratory (“Vet-Lab”, Brudzew, Poland) in order to determine the infection level with Eimeria oocysts. Depending on the intensity of Eimeria infection (II), the farm was assigned a coccidiosis-free status (II up to 9000 oocysts per 1 g of feces) or a coccidia-infected status (II > 9000).
The analysis was performed in two flocks: one was recognized as coccidiosis-free (designated HF) and the other (designated IF), in which the number of oocysts per 1 g of feces exceeded the acceptable level, was classified as an infected flock. The number of birds in both flocks at the beginning and at the end of the 42-day rearing period is shown in Table 1. The data collected in both flocks (based on the “Poultry Breeder’s Chart”) included: the age of the chickens, losses (including falls and culls for various reasons), body weight, weight gains, and daily feed intake.
Table
1. Number of broiler chickens at the beginning
and end of the rearing period in the healthy and
coccidia-infected flocks |
||
|
Flock size at the beginning of the rearing period |
Flock size at the end of the rearing period |
Healthy flock (HF), 12.02–25.03.2018 |
32,400 |
31,764 |
Infected flock (IF), 13.08–23.09.2018 |
30,100 |
29,032 |
Table
2. Comparison of losses in the healthy and
coccidia-infected flocks throughout the 42-day period with
indication of chicken falls and culls |
||||||||||||
Age of chickens, days |
Falls |
Culls |
Total losses |
|||||||||
HF |
IF |
HF |
IF |
HF |
IF |
|||||||
n |
% |
n |
% |
n |
% |
n |
% |
n |
% |
n |
% |
|
0–7 |
149 |
0.45 |
135 |
0.44 |
31 |
0.09 |
149 |
0.49 |
180 |
0.55 |
284 |
0.94 |
8–14 |
94 |
0.29 |
85 |
0.28 |
11 |
0.03 |
53 |
0.17 |
105 |
0.32 |
138 |
0.45 |
15–21 |
83 |
0.25 |
90 |
0.29 |
2 |
0.01 |
56 |
0.18 |
85 |
0.26 |
146 |
0.48 |
22–28 |
78 |
0.24 |
65 |
0.21 |
22 |
0.07 |
52 |
0.17 |
100 |
0.30 |
117 |
0.38 |
29–35 |
63 |
0.19 |
75 |
0.25 |
3 |
0.01 |
89 |
0.29 |
66 |
0.20 |
164 |
0.54 |
36–42 |
50 |
0.15 |
134 |
0.44 |
50 |
0.15 |
85 |
0.28 |
100 |
0.30 |
219 |
0.72 |
Total – Ogółem |
517 |
1.59 |
584 |
1.94 |
119 |
0.36 |
484 |
1.60 |
636 |
1.96 |
1068 |
3.54 |
χ2
for falls = 38.06, significant at P ≤ 0.01; χ2
for culls = 56.64 significant at P ≤ 0.01; χ2
for total losses = 23.36 significant at P ≤ 0.01. |
||||||||||||
Table
3. Mean body weight on consecutive rearing days
in the healthy and infected flocks |
|||||||||
Age of chickens, days |
Body weight, kg |
Age of chickens, days |
Body weight, kg |
||||||
HF |
IF |
HF |
IF |
||||||
x̄ |
CV |
x̄ |
CV |
x̄ |
CV |
x̄ |
CV |
||
1 |
0.04 |
10.35 |
0.04 |
11.17 |
22** |
0.99 |
11.36 |
0.66 |
12.61 |
2 |
0.06 |
11.69 |
0.06 |
10.36 |
24** |
1.22 |
12.15 |
0.93 |
13.21 |
3 |
0.08 |
10.98 |
0.07 |
12.47 |
26** |
1.37 |
13.33 |
1.05 |
14.33 |
6 |
0.17 |
12.24 |
0.09 |
12.57 |
28** |
1.57 |
13.91 |
1.24 |
13.97 |
8 |
0.22 |
13.54 |
0.16 |
13.57 |
30** |
1.77 |
12.81 |
1.31 |
14.03 |
10* |
0.30 |
11.23 |
0.19 |
13.80 |
32** |
1.90 |
12.56 |
1.43 |
14.12 |
12* |
0.37 |
10.73 |
0.26 |
13.16 |
34** |
2.07 |
11.87 |
1.57 |
14.78 |
14* |
0.44 |
12.22 |
0.33 |
12.63 |
36** |
2.11 |
11.99 |
1.72 |
15.07 |
16* |
0.54 |
13.11 |
0.44 |
14.21 |
38** |
2.21 |
13.08 |
1.98 |
15.02 |
18** |
0.71 |
10.81 |
0.52 |
13.72 |
40** |
2.45 |
13.27 |
2.19 |
15.87 |
20** |
0.81 |
12.56 |
0.64 |
13.45 |
42** |
2.65 |
13.54 |
2.23 |
14.84 |
Mean values in the group, statistically
significant differences: ** at P ≤ 0.01; * at P ≤ 0.05; CV
– coefficient of variation. |
|||||||||
Table
4. Feed intake in the groups of healthy (HF)
and coccidia-infected (IF) chickens |
||||||||
Age of chickens, days |
Feed intake per body weight gain, kg |
Mean feed intake per 1 kg body weight |
||||||
HF |
IF |
HF |
IF |
|||||
x̄ |
CV |
x̄ |
CV |
x̄ |
CV |
x̄ |
CV |
|
1 |
0.06 |
10.15 |
0.06 |
11.07 |
1.40 |
9.23 |
1.40 |
10.34 |
2 |
0.10 |
11.89 |
0.10 |
10.46 |
1.50 |
10.15 |
1.50 |
11.26 |
3 |
0.12 |
11.65 |
0.11 |
12.51 |
1.50 |
11.11 |
1.60 |
12.12 |
6 |
0.26 |
11.14 |
0.14 |
12.59 |
1.50 |
11.45 |
1.60 |
12.56 |
8 |
0.33 |
12.94 |
0.25 |
13.63 |
1.50 |
10.97 |
1.60 |
12.07 |
10 |
0.45* |
10.24 |
0.30* |
13.77 |
1.50 |
12.01 |
1.60 |
13.03 |
12 |
0.56* |
10.42 |
0.42* |
13.19 |
1.50 |
11.59 |
1.60 |
12.08 |
14 |
0.66* |
12.17 |
0.52* |
12.63 |
1.60 |
12.31 |
1.60 |
11.37 |
16 |
0.86* |
12.88 |
0.70* |
14.05 |
1.60 |
11.47 |
1.60 |
12.03 |
18 |
1.13** |
10.34 |
0.88** |
13.72 |
1.60 |
10.42 |
1.60 |
11.54 |
20 |
1.29* |
12.61 |
1.11* |
13.45 |
1.60* |
11.89 |
1.72* |
12.87 |
22 |
1.58** |
11.17 |
1.14** |
12.61 |
1.60* |
12.31 |
1.72* |
12.05 |
24 |
1.95** |
12.08 |
1.61** |
13.14 |
1.60* |
13.11 |
1.73* |
12.09 |
26 |
2.19** |
13.24 |
1.82** |
14.42 |
1.60* |
12.44 |
1.73* |
13.08 |
28 |
2.67** |
13.83 |
2.15** |
13.83 |
1.70 |
13.76 |
1.73 |
14.15 |
30 |
3.01** |
12.76 |
2.27** |
14.06 |
1.70* |
13.03 |
1.73* |
13.99 |
32 |
3.20** |
12.30 |
2.46** |
14.14 |
1.70 |
12.64 |
1.72 |
12.54 |
34 |
3.40** |
11.70 |
2.70** |
14.84 |
1.64* |
11.23 |
1.72* |
11.13 |
36 |
3.60** |
11.72 |
3.01** |
15.01 |
1.71 |
12.39 |
1.75 |
12.49 |
38 |
3.80** |
13.13 |
3.47** |
15.06 |
1.72 |
13.07 |
1.75 |
13.47 |
40 |
4.05* |
13.30 |
3.83* |
15.60 |
1.65** |
10.45 |
1.75** |
11.58 |
42 |
4.10* |
13.09 |
3.90* |
14.80 |
1.55** |
11.37 |
1.75** |
12.45 |
Mean feed intake per 1 body weight throughout the rearing period |
1.60* |
12.84 |
1.67* |
13.15 |
||||
Statistically significant differences: ** at P ≤ 0.01; * at P
≤ 0.05. |
||||||||
The evaluation of chicken losses during the rearing time was carried out in 7-day periods. In each period, the number of fallen and culled chickens was recorded to obtain the total number of losses in the individual rearing periods. Additionally, on the 1st, 2nd, and 3rd day of life of the chickens and in the subsequent 2-day periods, the mean feed intake per kg body weight was estimated based on the weight gains and the amount of ingested feed in both flocks at that time. In both flocks, the value of the European Production Efficiency Factor (EPEF) was calculated in the subsequent periods of chickens’ life using the following formula proposed by Kryeziu et al. [2018]Kryeziu, A.J., Mestani, N., Berisha, Sh., Kamberi M.A. (2018). The European performance indicators of broiler chickens as influenced by stocking density and sex. Agron. Res., 16(2), 483–491. Google Scholar:
$$EPEF= \frac{V \cdot BW}{TD \cdot FCR} $$
where:
\( V \) – viability (%),
\( BW \) – body weight (kg),
\( TD \) – trial duration (days).
\( FCR \) – feed convertion rate (kg feed/kg gain).
Statistica ver. 13.1.PL was used for the statistical analysis. The normality of the distribution of the random variable was checked using the Shapiro-Wilk test. The significance of the differences between the means was estimated with the Student's t-test, and the χ2 test was used to assess the relationship between the health status of the flocks and the frequency of bird losses (divided into falls and culls) in the subsequent rearing periods.
The data in Table 2 show that the health status of the analyzed flocks had a significant effect on the number of chicken losses during the rearing period, as the values of the χ2 test in the case of falls, culls, and total losses were significant at P ≤ 0.01. It was found that the total percentage of losses in the consecutive weeks was higher in the coccidia-infected flock and ranged between 0.38 and 0.94%. The greatest number of losses in this flock (284 chickens, 0.94% of the flock size) was recorded in the first period of 0–7 days. Slightly fewer birds (219, 0.72%) were lost on days 36–42 of rearing. The losses between days 29 and 35 were estimated at 0.54% (164 chickens). The smallest percentage of losses was recorded on rearing days 22–28. The losses reached 117 birds, which accounted for 0.38% of the analyzed group. The total percentage of losses during the 42 days of rearing in the infected group was 3.54% of the entire flock, with 1.59% (517 individuals) of falls and 0.36% (119 individuals) of culls for other reasons. In Ethiopia [Kinung'hi et al. 2004Kinung'hi, S.M., Tilahun, G., Hafez, H.M., Woldemeskel, M., Kyule, M., Grainer, M., Baumann, M.P.O. (2004). Assessment of economic impact caused by poultry coccidiosis in small and large scale poultry farms in Debre Zeit, Ethiopia. Int. J. Poultry Sci., 3(11), 715–718. https://doi.org/10.3923/ijps.2004.715.718], the mortality rate related to Eimeria infections was estimated at 13.3–14.5%, depending on the production scale. In turn, in a study conducted in Great Britain, Blake et al. [2020]Blake, D.P., Knox, J., Dehaeck, B., Huntington, B., Rathinam, T., Ravipati, V., Ayoade, S., Gilbert, W., Adebambo, A.O., Jatau, I.D., Raman, M., Parker, D., Rushton, J., Tomley, F.M. (2020). Re-calculating the cost of coccidiosis in chickens. Vet. Res., 51, No115. https://doi.org/10.1186/s13567-020-00837-2 reported 2% of chicken falls and culls due to coccidiosis.
Table
5. Values of the European Production Efficiency
Factor (EPEF) on the consecutive rearing days in the healthy and
infected flocks |
|||||
Age of chickens, days |
EPEF scores |
Age of chickens, days |
EPEF scores |
||
HF |
IF |
HF |
IF |
||
1 |
6.80 |
6.80 |
22** |
147.31 |
91.63 |
2 |
9.52 |
9.52 |
24** |
181.53 |
128.12 |
3 |
12.70 |
10.75 |
26** |
203.85 |
144.49 |
6* |
26.98 |
13.82 |
28* |
219.87 |
170.64 |
8* |
34.92 |
24.58 |
30** |
247.87 |
180.27 |
10** |
47.61 |
28.27 |
32** |
266.08 |
197.93 |
12** |
58.72 |
39.43 |
34** |
300.49 |
217.31 |
14** |
65.47 |
48.51 |
36** |
293.76 |
233.99 |
16* |
80.35 |
65.47 |
38* |
305.89 |
269.36 |
18** |
104.90 |
77.82 |
40** |
353.50 |
297.93 |
20** |
119.78 |
89.14 |
42** |
407.03 |
303.37 |
Statistically significant differences: ** – at P ≤ 0.01;
* – at P ≤ 0.05. |
|||||
In the coccidiosis-free flock, the largest numbers of losses were recorded during the period of 0–7 days, as in the flock infected with Eimeria protozoa. The number amounted to 180 chickens, which constituted 0.55% of the analyzed group. The subsequent weeks of rearing were associated with lower cull and fall rates in the flock, i.e. from 0.32% (days 8–14) to 0.26% (days 15–21). The lowest numbers of losses in this flock, i.e. 66 individuals accounting for 0.20% of the group, were recorded on days 29–35.
Body weight and weight gains in individual rearing periods as well as feed intake per 1 kg body weight are important indicators of the effectiveness of broiler chicken rearing (Tables 3 and 4). The analysis of these indicators shows (Table 3) that the growth rate in the chickens from the healthy flock was on average 0.09 kg per 2 days in the first half of rearing (before day 22), whereas a higher rate, i.e. on average 0.10–0.20 kg per 2 days, was noted in the last three weeks (from day 22). Consequently, the broilers from this flock reached a final weight of 2.65 kg. A lower growth rate was recorded in the chickens from the infected flock. Between the 3rd and 6th day of life, the mean weight of the chickens increased by only 0.02 kg. Hence, after the 6th day of life, the mean body weight of broilers from the flock infected with coccidian oocysts was statistically significantly different (P ≤ 0.05 or P ≤ 0.01) in comparison with the body weight of chickens reared in the healthy flock. In the subsequent two-day periods, the chicken growth rate slightly increased, but the weight gains were significantly lower than in the healthy flock. The mean value of this parameter was approx. 0.07 kg per 2 days between days 8 and 22 but increased to approx. 0.14 kg per 2 days from day 22 to the end of the rearing period. Consequently, the final body weight of broilers from the flock infected with coccidian oocysts reached the value of 2.23 kg. It was by 0.42 kg lower than the value noted in the healthy chicken group (P ≤ 0.01). Györke et al. [2016]Györke, A., Kalmár, Z., Pop, L.M., Şuteu, O.L. (2016). The economic impact of infection with Eimeria spp. in broiler farms from Romania. R. Bras. Zootec., 45(5), 273–280. https://doi.org/10.1590/S1806-92902016000500010 reported mean weight gains at the level of 54.8 g per day in Eimeria infected flocks, with values ranging from 42.3 to 62.4 g per day per chicken, depending on the size of the flock. As demonstrated by Kipper et al. [2013]Kipper, M., Andretta, I., Lehnen, C.R., Lovatto, P.A., Gonzalez Monteiroa, S. (2013). Meta-analysis of the performance variation in broilers experimentally challenged by Eimeria spp. Vet. Parasit., 196, 77–84. https://doi.org/10.1016/j.vetpar.2013.01.013, broilers infected with various Eimeria species achieved 4.6–10% lower body weight gains at a constant feed intake than uninfected birds. As shown by the authors, a 9.5% increase in feed intake in coccidia-infected broiler chickens, compared with disease-free birds, ensures weight gains similar to those in healthy birds. Greater inhibition of growth in Eimeria-infected chickens was indicated by Jenkins et al. [2008]Jenkins, M., Allen, P., Wilkins, G., Klopp, S., Miska, K. (2008). Eimeria praecox infection ameliorates effects of Eimeria maxima infection in chickens. Vet. Parasitol., 155, 10–14. https://doi.org/10.1016/j.vetpar.2008.04.013, who reported that the weight gain in this group of birds corresponded to 48–90% of that in infection-free chickens.
On the first day of life of the chickens, the feed intake in the coccidiosis-free and infected flocks was identical, i.e. 0.06 kg per weight gain and 1.4 kg per 1 kg body weight (Table 4). It was found that the feed intake on the subsequent days of life increased systematically in both flocks. In the healthy flock, it increased from 0.10 kg on the 2nd day of life to 4.10 kg on the last rearing day. The mean feed intake per 1 kg body weight throughout the rearing period in this group was 1.60 kg. In the flock infected with coccidian oocysts, the feed intake vs. the weight gain increased from 0.10 kg on the 2nd day of life to 3.9 kg on the 42nd day. Compared with the healthy flock, the mean feed intake per 1 kg body weight throughout the rearing period of the infected broiler chickens was significantly higher (P ≤ 0.05) by 0.07 kg and amounted to 1.67 kg. Increased feed intake in chickens with coccidiosis was reported by Kipper et al. [2013]Kipper, M., Andretta, I., Lehnen, C.R., Lovatto, P.A., Gonzalez Monteiroa, S. (2013). Meta-analysis of the performance variation in broilers experimentally challenged by Eimeria spp. Vet. Parasit., 196, 77–84. https://doi.org/10.1016/j.vetpar.2013.01.013. The authors indicated that birds with multi-species infection as the etiological factor of coccidiosis consumed 5% more feed than control (healthy) birds. In the case of E. maxima infection, the increase in feed intake was higher, 8%.
The data collected in both flocks were used for calculation of the European Production Efficiency Factor (EPEF) (Table 5). As reported by Mazanowski [2011]Mazanowski, A. (2011). Nowoczesna produkcja kurcząt brojlerów [Modern production of broiler chickens]. Wyd. ProAgricola, Gietrzwałd, 245 [in Polish]. Google Scholar, the value of this indicator is mainly influenced by environmental conditions and nutrition. The present study showed that the lowest values were recorded on the first two days of chickens' life. They were the same in both flocks, i.e. 6.80 (1st day of life) and 9.52 (2nd day of life). On the subsequent days, the EPEF in both flocks increased systematically, with higher values calculated for the coccidiosis-free flock. On the 42nd rearing day, the value of the factor was 407.03, which was by 103.66 higher (P ≤ 0.01) than that in the Eimeria-infected flock. In the latter flock, this indicator had substantially lower values throughout the chicken lifespan. These results agree with the findings reported by Haug et al. [2008]Haug, A., Gjevre, A-G., Skjerve, E., Kaldhusdal, M. (2008). A survey of the economic impact of subclinical Eimeria infections in broiler chickens in Norway. Avian Path., 37(3), 333–341. https://doi.org/10.1080/03079450802050705, who described a significant decrease in EPEF values in flocks with the number of oocysts per gram of feces exceeding 50,000, compared with coccidiosis-free flocks.
The study was financed from funds allocated to maintenance of the research potential of the research units.
Received: 10 Dec 2020
Accepted: 31 Dec 2020
Published online: 19 Mar 2021
Accesses: 985
Januś, E., Sablik, P., (2020). Evaluation of broiler chickens rearing parameters in relation to intensity of infection with Eimeria protozoa. Acta Sci. Pol. Zootechnica, 19(4), 79–86. DOI: 10.21005/asp.2020.19.4.10.