The mean of RBC reported in the present study was lower than the reference range of Kramer et al., (2006), but it approaches that of Plaza Cuadrado et al., (2019) in Colombia in ewesat the end of gestation of the Pelo Criollos breed. El-Sayed et al., (2020) in Egypt recorded a very low mean of RBC in Barki ewes during the last stage of pregnancy compared to the mean reported in our results.

The Hb value recorded in ewes at the end of gestation in our study shows a decrease compared to the value reported in ewes during late pregnancy in the study by El-Malky et al., (2019) in Egypt in the Barki and Ossimi breed, while Kandiel et al., (2016) recorded a lower mean of Hb in the Barki breed compared to the mean obtained in this study. We recorded a lower mean of Ht in pregnant ewes in the last stage compared to the mean obtained by Sharma et al., (2015) in India in the breed of Himalayan Gaddi and Zvonko et al., (2015) in Croatia in breed Dubrovnik and breed Zeta zuja.

The decrease in the values of RBC, Hb, and Ht in this study could be due to hemodilution. This is a physiological response to the decrease of blood viscosity, to improve blood supply to small vessels and those newly formed in the maternal uterus and placenta (Yaqub et al., 2021). This agrees with the study of Greguła-Kania et al., (2020) in Poland, which recorded a significant decrease (P ≤ 0.05) in RBC and Ht values in ewes during late gestation compared to the pre-gestation period. The decrease ofred blood count values in Rembi ewes during late pregnancy in our study could also be due to the metabolic diseases which can be installedin ewes during this period, such as the clinical and sub-clinical pregnancy toxemia, the study of Marutsova and Marutsov, (2015) in Bulgaria in Lacaune ewes with clinical and subclinical pregnancy toxemia recorded a significant decrease (P ≤ 0.05) in red blood counts (RBC, Hb, and Ht), which could be associated with hypoglycemia and ketogenesis linked to this pathology. This was very clear in our study in which we recorded a decrease in RBC, Hb, and Ht with a positive correlation between thesevalues and glucose (Table 3). This indicates that the hypoglycemia encountered in ewes at the end of gestation following the increase in energy requirements could be the cause of anemia in these ewes during this period.

In our study, the values of MCV and MCHC were within the standard references of Kramer et al., (2006) regardless of the decrease in the values of RBC, Hb, and Ht. MCV means obtained in this study were lower than that of Zvonko et al., (2015), and higher than that of Bezerra et al., (2017). According to the study byGreguła-Kania et al., (2020), Hb, MCV, and MCH values were significantly elevated (P ≤ 0.05) during the peripartum period despite the decrease in the number of erythrocytes. The authors related the increase of hemoglobin concentration in erythrocytes to the organism's compensation for RBC deficiency, which is a physiological response thatpreserves oxygen content in the blood (Greguła-Kania et al., 2020).

In our ewes, the MCV value was influenced by the number of fetuses and highly influenced by age and parity with a positive correlation with the WBC and Lym values (Table 3).

In addition, the PLA value was highly influenced by age and parity (P<0.001) registering a negative correlation with WBC and Neu, it also registered another negative correlation with MCV. Along with this result, the mean of PLA recorded in ewes during late pregnancy in our study was lower thanthat obtained by Plaza Cuadrado et al., (2019), and was in the reference value of Kramer et al., (2006). We found that this means was highest compared to that obtained by Sharma et al., (2015) in ewes in the last third of their pregnancy period. According to Plaza Cuadrado et al., (2019), the thrombocytosis encountered in pregnant ewes could be due to a physical activity that stimulates the secretion of epinephrine by causing splenocontraction, and consequently, mobilization of the stored platelets can be toward the blood circulation. This could be due to a hyperproduction of thrombopoietin which occurs after or in association with a bleeding process, particularly when bleeding causes iron deficiency anemia. Also, in case of serum iron losses caused by gastrointestinal parasites, chronic anemia can set in these animals causing secondary thrombocytosis. Therefore, we can link the average platelets encountered in ewes at the end of pregnancy in our study to the decrease in iron which marked a much-reduced mean.

The value of WBC obtained in our study was higher than the reference value, and than those obtained in pregnant ewes by Soliman (2014) in Egyptianewes during the late pregnancy of Ossimi Breed, Bezerra et al., (2017) and Greguła-Kania et al., (2020). Among the different types of leukocytes, the mean of neutrophils was highest in our study, followed by the mean of monocytes. The relationship between granulocytes/lymphocytes can be used as a physiological indicator of stress. Our study recorded a high ratio of neutrophils /lymphocyte (N / L) in pregnant Rembi ewes, and this is consistent with the study of Soliman (2014), and Sharma et al., (2015), and Greguła-Kania et al., (2020).

According to Soliman (2014), the increase in the N / L ratio could be because the stress of gestation stimulates the anterior pituitary gland to secrete ACTH, which in turn induces the adrenal cortex to produce glucocorticoids, by causing mobilization of neutrophils from the body pool to the peripheral circulation. Greguła-Kania et al., (2020) also attributed the decrease in lymphocytes and the increase in granulocytes at the end of gestation and postpartum to the release of cortisol in case of metabolic stress related to gestation and lactation period. We recorded a significant influence of parity on the WBC values, it was very lower in multiparous ewes compared to the primiparous.

Glycemia mean obtained in pregnant Rembi ewes in the last stage of pregnancy was greatly reduced compared with those obtained in ewes at the end of gestation by Berkani et al., (2017) in Algeria in the Ouled djellal breed, Mohammadi et al., (2016) in Iran in the Mekouei breed, Ismaeel et al., (2018) in Iraq among the local breed. According to these authors, the decrease of glycemia in ewes during late gestation seems to be related to the increase in the need forthe fetoplacental unit in glucose, because 70% of fetal growth takes place during the last six weeks of pregnancy. This is contrasting with the study of Kandiel et al., (2016) in Egypt which recorded an increase in the serum glucose value in pregnant ewes during this period. Kandiel et al., (2016) explained this increase in glucose by the decrease in insulin levels which could be granted to the negative energy balance, and this promotes lipolysis and displacement of energy substrates away from the stores of adipose tissue. This is because the mobilization of stored energy at the end of gestation is essential to assemble the needs of fetal growth and mammary gland development. In our results, the influence of parity on the blood glucose value was very significant (P< 0.01). It was significantly reduced in multiparous compared to primiparous, these results agree with those obtained by Damián et al., (2020) in Uruguay.

The mean value of TP in ewes at the end of gestation in this study was within the reference standards of Kaneko et al., (2008). This value was higher than that of Ismaeel et al., (2018) in Iraq, and lower than that of Mohammadi et al., (2016) in Iran. According to Ismaeel et al., (2018), hypoproteinemia in ewes during late pregnancy could be due to embryonic growth, which leads to the consumption of large amounts of maternal amino acids to maintain fetal muscle development and the transmission of immunoglobulins from the blood plasma to the mammary gland for the production of colostrum during the last trimester of gestation.Mohammadi et al., (2016), however, linked the increase in serum TP concentration to the formation of globulin which is triggered in the three to four weeks before parturition to produce colostrum rich in antibodies. In our study, plasma TP concentration was significantly (P< 0.05) increased in ewes aged 6 years compared to those having 2 years, and significantly increased in multiparous compared to primiparous ewes.

The recorded iron mean in our ewes was lower compared to the reference value, and to those obtained by Teleb et al., (2019) in Egypt in pregnant ewes in the last thirds of the Saidi breed, and Cihan et al., (2016) in Turkey in ewes of the Ivesi breed. Cihan et al., (2016) have associated the decrease in plasma iron concentration at the end of gestation with fetal consumption of this mineral. According to the study by Darwish and El Ebissy, (2019) in Egypt, iron concentration was significantly reduced in healthy pregnant Barkiewes at the end of gestation compared to ewes from the control group (not pregnant), and compared to those with pregnancy toxemia. These authors have linked hypoferremia and hypoferritinemia (depletion of iron stores) in ewes during late pregnancy to increased fetal demand and increased red mass at this moment. While they attributed the hyperferremia in ewes with pregnancy toxemia to liver damage associated with this disease and the dependent release of Kupffer cells that store iron, this hypothesis was confirmed by the positive correlation recorded between liver enzymes and iron in their study. Whereas in our study the iron value was significantly influenced (P≤ 0.05) by age of ewes, when it was decreased in old (6 years) ewes compared to those having 2 years (Table 2).

Our results showed that the plasma cholesterol mean recorded in ewes at the end of gestation was higher compared to the range of references, and to that recorded in ewes at the end of gestation by Berkani et al., (2018) in Algeria. However, it was lower than the value recorded by El-Bassiouny et al., (2018) in Egypt in Barki ewes in the last third of their pregnancy.

The increase in cholesterol in this study could be linked to the decrease in the sensitivity of adipose tissue to the action of insulin which decreases in ewes at the end of gestation (Mohammadi et al., 2016). The study of El-Malky et al., (2019) in Egypt did not record a significant influence of the physiological stage on cholesterol. In our results, the cholesterol values were significantly decreased (P≤ 0.05) in ewes with 2 fetuses compared to those having a single fetus.

Conclusion

The decrease in RBC, Hb, Ht, and iron values in this study indicates that Rembi ewes in late gestation are subjected to develop anemia. The energy deficit that develops in ewes at the end of pregnancy can induce some changes in hematological parameters and thus causing a decrease in the indices of red blood count. In our study, age and parity are the factors that can most influence the hematological and biochemical parameters in ewes during late gestation. To prevent the apparition of anemia in pregnant ewes, the energy status of these ewes should be improved in the quantity and quality of distributed food. It is also essential that the various parasitic infections that can worsen anemia in ewes during this period are tackled.

ACKNOWLEDGMENTS: The authors would like to thank all of the members of the medical hematology-biochemistry laboratory of Tiaret Institute of Veterinary Sciences for their assistance in this experiment. My Deepest thanks are due to Dr. Benahmed Laid for his contribution to sample collection.

CONFLICT OF INTEREST: None

FINANCIAL SUPPORT: None

ETHICS STATEMENT: All experiments were complied with the Algerian legislation (Law number 95-322/1995) inherent to protect animals designed for experiments or other scientific purposes, also the guidelines of the Algerian Association of Experimental Animal Sciences (AASEA approved under the agreement number 45/DGLPAG/DVA/SDA/14).