Ibadan, Oyo State is located in the South West Region of Nigeria. Latitude 7^o North and longitude 4^o East bisect the state into four nearly equal parts. The daily average temperature is 26.46°C. The climate is equatorial notably with dry and wet seasons with relatively high humidity [11].

A total of three hundred and ninety (390) birds comprising layers chickens, broilers chickens, local chickens, turkeys, local ducks, and pigeons were sampled for the purpose of this study, based on their breed, sex, rearing, location, season of sampling, clinical signs, their age, and relative ease of accessibility of transportation.

Systematic simple random sampling methods were used to select the birds taking into consideration number of samples according to each species across five local government areas in Ibadan, Oyo state.

A total of 390 birds of different breed, age, sex, and rearing methods, from 5 different locations in Ibadan were examined for the presence of haemoparasites (Table 1).

Out of 390 birds examined, 174 (44.6 %) were infected with one or more blood parasites. Five species of hemoparasites were found during this study, including Plasmodium, Haemoparoteus, Leucocytozoon, Babesia, and Microfilaria. In single infection Plasmodium spp (Plate 1A) was the most prevalent haemoparasite (51.72%) followed by Haemoproteus spp (Plate 1B) 3.45%, Babesia (Plate 1C) 3.45%, and Microfilaria (Plate 1D) 1.72% (Table 1). In mixed infection Plasmodium and Haemoproteus (19 %), Plasmodium and Microfilaria (8.62%), Babesia and Plasmodium (6.90%), Babesia and Haemoproteus (1.72%), Plasmodium and Leukocytozoon (Plate E) 1.72%, in triple infection Babesia, Haemoproteus and Plasmodium (1.72%).

Clinical signs observed in affected poultry birds varied such as fever, depression, anorexia, loss of body weight, dyspnea, loss of appetite, emaciation, listlessness, difficulty in breathing, changes in feather appearance, weakness, and lameness in one or both legs. The prevalence based on breed is shown in Table 2, with the highest in layers. Varying incidence was also observed with locations (Table 3), sex, age, rearing methods, and season (Table 4).

The hematologic findings showed that the mean packed cell volume PCV (26.8 ± 1.5), plasma proteins (5.8 ± 1.1), Neutrophil (4.5 ± 0.2), Eosinophil (0.5 ± 0.1) and mean corpuscular hemoglobin concentration (32.4 ± 1.1) values of the infected birds were lower than the non-infected birds, but the mean, Basophils (0.1 ± 0.0), Lymphocyte (9.7 ± 0.3), Monocyte (0.6 ± 0.1), and WBC (1.5 ± 0.4), values of infected birds was higher than non-infected (Table 5). The infected birds showed severe anaemia, hypoprothinaemia, neutropaemia, and easinopaenia, whereas also showed leucocytosis, lymphocytosis, and monocytosis. The erythrocyte diameter of the non-infected birds was higher than the infected ones as the infected birds had a lot of microcytes in peripheral blood. There was also haemolytic anemia in a few of the birds. Fragments, micronuclei, blebbed, and notched nuclear changes were observed in the birds with haemoparasitic infection; however, the severity of these changes was more in the haemoproteus and plasmodium infections. The biochemistry findings showed that the mean of Albumin (33.1 ± 1.2), AST (54.9 ± 0.9), ALT (88.3 ± 4.1), ALP (1.5 ± 0.7), BUN (14.9 ± 1.6), Potassium (3.2 ± 0.2), and Calcium (1.5 ± 0.3) values of the infected bird were not significantly different to the non-infected birds, but the mean of Globulin (36.0 ± 1.4), Bilirubin (7.5 ± 0.3), Glucose (55.3 ± 6.7), Creatinin (26.3 ± 1.9), Sodium(1.1 ± 0.8), Phosphorus (1.9 ± 0.2), and Amylase (1.4 ± 0.2) values of infected birds were higher than the non-infected (p ≥ 0.05) (Table 6).

Furthermore, RBC morphological changes were observed in varying degrees, with 213 (54.6%) samples showing no changes, while 9 (2.31%) showing RBC morphological changes, 93 (23.85%) exhibiting mild alterations, 63 (16.15%) displaying moderate changes, and 9 (2.31%) demonstrating severe changes (Table 7). Also toxic changes in neutrophils (Plate F). Notably, there was an association between haemoparasitemia and the severity of RBC morphological changes, suggesting a potential relationship between parasitic infection and erythrocyte pathology in birds. On the relationship between parasite presence and changes in WBC morphology; 216 cases were classified as negative, indicating no observable impact of parasites on WBC morphology. 174 cases were classified as positive, suggesting that parasites were associated with changes in WBC morphology. Among the positive cases: 132 cases exhibited mild changes in WBC morphology. 9 cases showed moderate changes in WBC morphology (Table 7). The absence of moderate changes in WBC morphology among negative cases indicates that such changes are likely attributed to the presence of parasites.

Of the 390 samples analyzed, 174 (44.6%) tested positive for haemoparasites, indicating a significant presence of these pathogens within the avian population under study. The clinical signs aligned with findings from previous research and it is in agreement with Mirzaei et al. [12]. Increased intensity of parasitic infection or different parasites in the same birds may contribute to the mortality of Poultry birds’ species because hemoparasites cause anemia by affecting red blood cells, which may be further damaged by immune response [14,15]. The level of anemia observed in the birds infected with the haemoparasite correlated as most of the birds with some haemoparasites turned out to have anaemia, microcytosis, and hypoprotaemia. The prevalence and distribution of the different hemoparasites found in this investigation were in disagreement with Naqvi et al. [16] who encountered only three genera parasites (Haemoproteus, Leucocytozoon, and Plasmodium). The high distribution of haemoparasites in this study may be due to variations in climatic conditions and seasons of the research, which are some of the determinants of the activities of vectors which transmit these parasites. Daphey and Nmorsi [17] conclude that a number of factors, including rainfall, changes in habitat composition, host age and time of day of collection, proximity to vector breeding grounds, relative host resistance, and local temperature variations, can influence variations in prevalence.

The overall prevalence of parasites 44.6% observed in this study is significantly lower than 53.3% that was reported by Ogbaje et al. [18] in Markurdi Major Markets (Nigeria). This may be due to the geographical variation including temperature, humidity and the presence of suitable vectors. The high prevalence of Plasmodium spp with 51.72%, suggests the burden followed by Haemoproteus and Babesia spp with 3.45% and the least prevalent were in microfilaria and leukocytozoon (1.72%). It is an agreement with many research conducted in Nigeria including Ogbaje et al. [18] who reported the highest prevalence of plasmodium may be due to the vector abundance because plasmodium species are commonly transmitted by mosquitoes, which are widespread and abundant in various environment [19].

The findings of this study indicate a notable discrepancy in the prevalence of haemoparasites between different breed. Specifically, the data suggests that laying birds exhibit a higher incidence of haemoparasitic infections compared to broilers. This disparity could be attributed to several factors inherent to the respective production systems and biological characteristics of the chicken breeds. Layers chickens, which are typically raised for egg production over an extended period, may experience higher exposure to environmental conditions conducive to haemoparasite transmission. Factors such as prolonged exposure to outdoor environments, increased contact with vectors, and potential stressors associated with egg-laying activities could contribute to their heightened susceptibility. Furthermore, the relatively longer lifespan of layers compared to broilers may provide a larger window of opportunity for haemoparasite acquisition and accumulation over time. Additionally, selective breeding for enhanced growth rates in broilers may inadvertently confer some degree of resistance or tolerance to certain parasites. This investigation showed that the poultry birds within cage rearing (62%) were more infected than the floor rearing (38%). That is very surprising in floor rearing birds have more space to move around and access to litter. This may influence exposure to parasites whereases in cages rearing birds are confined which can limited movement that affect parasites transmission. From floor rearing there is potential of exposing birds to parasites present in the contact with feces and liter otherwise from cages rearing is limited contact with liter, reducing the direct exposure to parasites found in feces.

According to the different locations that samples were collected to the farm G were most prevalent with haemoparasites, and the least prevalent was in farm. This could be due to the several factors such as environmental condition which is more preserved, vector population, management system and climate and seasonal patterns. And more so the number of birds sampled in this area, further studies should cover more birds in the different locations. The high prevalence of male birds compared to the females in this study is an disagreement with Scaglione et al. [20] and Opara et al. [21] who indicated that the females were more parasitized because the reduction of the locomotion activity during the nesting period may contribute as factor of increasing the probability of the infection with haemosporidians. According to Naqvi et al. [16] the precise reason for increased haemoparasitic infection in females is unknown, however higher progesterone and prolactin levels often weaken the immune system and increase susceptibility to infection in general. Well, the reason for our observation could be increase the immune response of the male birds. The low prevalent rate recorded in younger birds, while higher in adults’ birds that may be due to repeated parasite exposure, the choice of habitats, different migration and movement pattern compared to young and interactions with vectors. Gametocytes encircle the nucleus of parasitized erythrocytes, leading to hemolysis and resulting in anemia. Haemoproteus meleagridis causes fatalities in young poults and surviving turkeys may be lame and have reduced growth and weight gain according to Cardona et al. [22]. Ogbaje et al. [18] showed that there were no differences in the prevalence of bird infections in different age groups.

The prevalence of poultry infection with parasites were higher for the birds that were sampled during rainy season than dry season is an agreement with Ogbaje et al. [18] that may be due to vector survival and environmental condition because during the rainy season usually there is a lot of sources of water that can create suitable habitats for both parasites and their vector. The establishment of preventative and control strategies for both domesticated and wild fowl could benefit greatly from the significant role that seasonality plays in the vector and the spread of haemoparasites according to Omonona et al. [23]. The results showed that there were statistical significance differences for some of the haematology of the infected and non-infected Poultry birds, just as was reported by Ogbaje et al. [23]. According to Daphey and Nmorsi [17] the mean value of PCV, Hb, RBC, Lymphocyte, MCV, and MCHC in the infected with blood parasites were lower than the non-infected. These results are similar and the anemia was regenerative because newly produced red blood cells increase in numbers and these cells are larger than mature cells. If the value is below normal and the bird is anemic, then this indicates a non-regenerative state according to Mitchell et al. [24]. According to Motta et al. [25] the monocytes play an important role in phagocytic activity and antigen processing in birds. Gaspar et al. [26] had reported that acute phase response to disease is often accompanied by the recruitment of neutrophils into circulating blood resulting in a blood neutrophilia. Like neutrophils, their counterpart in birds, heterophils, are critically involved in the immediate response to pathogens [27]. There are two common types of changes observed in heterophils during the course of disease processes in birds. One change is the presence of immature cells in the peripheral blood, representing recruitment of cells from the bone marrow in response to cytokines and other inflammatory mediators; the other important change observed in avian heterophils during disease is toxic change [13]. The Globulin, Bilirubin, Glucose, Creatinine, Phosphorus and Amylase were higher in infected than the non-infected whereases the albumin, AST, ALT, ALP, BUN, Potassium and Calcium were higher in non-infected birds than the infected birds. The high values of Asparate Aminotransferase, Bilirubin and creatinine and Amylase revealed in this study with infected bird may indicate liver disease, damage of skeletal muscle with myocardial diseases and proventricular dilation diseases. Plasma biochemistry is especially important in avian species, which frequently show minimal overt clinical signs of disease, even when seriously ill. Therefore, the need for accurate and useful biochemical analysis to successfully diagnose and treat avian species cannot be overemphasized, Harr et al. [28]. The hematological and biochemical parameters of poultry birds were tested to know the differences between the hematological parameters and the biochemical parameters of the species [29,30].

Globulins are produced in the liver. Globulins, albumins, and fibrinogen are major blood proteins. Low globulin can be a sign of liver or kidney disease. High level may indicate infection, inflammatory disease or immune disorders. High levels of globulin may cause such type of cancers like multiple myeloma, malignant lymphoma. Also, Globulin level has been used as indicator of immune responses and sources of antibody production. They also help during the time of fight infection and transport of nutrients. The increase level of globulin concentration might confer higher disease resistance capacity of chicken Mohanty et al. [29]. A slight degree of polychromasia is common in healthy birds; one reference interval for healthy psittacines reports that polychromatophils comprised 0.41%–6.78% of all erythrocytes. Slight anisocytosis is also considered an unremarkable finding in birds [24,26]. Prominent anisocytosis may be seen with regenerative anemia or with dyserythropoiesis, however, and was seen in blood smears from marine birds exposed to crude oil [17]. Haematological and biochemical studies, which can reveal the function of the kidney, liver, and bone marrow, among other organs, are an invaluable resource for learning about avian health [30].The establishment of preventative and control strategies for both domesticated and wild fowl could benefit greatly from the significant role that seasonality plays in the vector and the spread of haemoparasites [23].

The comparative analysis of haematological parameters and biochemical profiles in poultry birds has revealed crucial value in their health status. This study establishes these parameters as reliable indicators of avian health. Furthermore, through extensive examination, it has been determined that variables such as species, sex, location, breed, management system, and origin significantly influence the prevalence of haemoparasites among poultry populations. Particularly, avian haemoparasites, including those from the genera Plasmodium, Haemoproteus, and Leucocytozoon, exhibit diverse prevalence rates, shaped by various environmental factors. This research contributes to a deeper understanding of avian health management and underscores the importance of monitoring haematological parameters and blood profiles in poultry farming practice To reduce haemoparasites infections in Poultry birds, it is recommended to implement strict biosecurity protocols to prevent the entry of infected birds or vectors like mosquitos, tick and flies, insecticides or acaricides use approved for poultry birds and mosquito net may play important role for preventing blood parasites infection, regular health checks and maintaining a clean and dry environment to avoid the growth of parasites vectors.

Compliance with ethical standards: The study was carried out in accordance with the guidelines of the regulation approved by the University of Ibadan’s Animal care and use Research Ethics Committee (UI-ACUREC/034-0423/18).

Consent for publication was obtained for every individual person’s data included in the study.

This work was supported by the African Union Commission under Grant Pan African University life and Earth Sciences Institute (including Health and Agriculture), Ibadan, Nigeria.

The authors report there are no competing interests to declare.

Informed consent was obtained from all individual participants included in the study.

The protocol was reviewed and approved by institutional animal care and use research ethics committee with number (UI-ACUREC/034-0423/18) All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.