Effects of Season, Productive State, Age and Agro-ecology on Blood Biochemical Characteristics of Dromedary Camels (Camelus dromedarius) in Natural Browsing Environment

The camel (Camelus dromedarius, or one-humped camel) is a very dominating and widely distributed animal in Sub-Saharan Africa, particularly in the least developed countries. It is critical to human life and utilisation in dry and desert areas. In the face of growing desertification and the recurrence of drought and famine in Sub-Saharan Africa, particularly in East Africa, the camel plays an important role as a source of milk, meat and draught power. The camel’s main purpose is directly tied to its exceptional tolerance to exceedingly severe situations and it can thrive where no other household animal can (Oselu et al., 2022; Rahimi et al., 2022).
       
Camel productivity is limited by inadequate nutrition (Hamad et al., 2018; Xulu et al., 2022). Animal nutritional status is important since it is a basic measure of animal health and productivity because the entire production system is built on traditional and vast poor rangelands that have typically deteriorated due to a variety of factors (Yagil and Etzion, 1980). Camel nutritional status and thus blood contents, appear to be important, as do blood value comparisons under different management systems, because these values represent the animal’s well-being (Abdoun et al., 2011; Ogunbosoye et al., 2015). Furthermore, camel nutrition is often the outcome of a series of interconnected factors such as season and environment. The nutritional composition and physical qualities of the forage available in various settings and seasons in the ration, on the other hand, have a significant impact on camel food utilisation (Abd El-Salaam and Arafa, 2018). Payne et al., (1970) and Lamo et al., (2020) detected nutritional inadequacies by examining biochemical features of animal blood.  
       
Blood metabolites are increasingly being used to determine an animal’s nutritional status (Momenah, 2014; Faraz et al., 2022). Blood constituent analysis can provide useful information about an animal’s overall health (Babeker et al., 2013; Momenah, 2014). Blood metabolite levels, on the other hand, reveal the extent of energy, protein and other nutrition metabolism in animals Faraz. (2021). Serum metabolite profiling, without a doubt, provides more information than body condition rating (Faye and Bengoumi 2018; Worku et al., 2021). Blood biochemical studies provide a wealth of information about an animal’s nutritional health and well-being and can thus be used to assess overall health. It has the potential to be a valuable tool for monitoring camel health (Faraz et al., 2020). The nutritional health of dromedary camels has never been studied before in the Boran Plateau and this is the first study of its sort. Obtaining data on blood biochemical profiles could thus serve as a foundation for future study and planning. As a result, the objectives of this study were to establish the nutritional condition of wild browsing dromedary camels of varied ages and productive statuses using blood serum variables and to assess the influence of seasonal and environmental factors.

The experiment samples were collected in April and October 2022 in two areas of the Borana Zone in Southern Ethiopia: hot lowland (Gamojji) and semi-arid (Badda Dare). This classification is based on annual and monthly mean temperature and rainfall, seasonal changes in rainfall and native vegetation type. The hot lowland (Gamojji) is located at 04^o95.72' latitude, 037^o80.91' longitude and 1116 m elevation. The semi-arid (Badda Dare) region is located at 05^o11.04' latitude and 038^o27.46' longitude, with an elevation of 1650 m. Rainfall in the study areas is bimodal, with a mean annual rainfall of 500 mm and significant inter-annual variability (Angassa and Oba, 2007). The main rainy season (Mid-March to Mid-May) accounts for 70% of annual rainfall, while the short rainy season (Mid-September to Mid-November) accounts for 30% (Megersa et al., 2014).
       
A total of 36 camels from two herds in two Borana plateau agroecology were used for blood sampling. The camels were classified into three groups (G) based on their age (>8 years, 5-8 years, or less than 5 years) and productive status (milking, pregnant, or young). In arid and semi-arid agroecology G1 consists of 12 milking camels, G2 consists of 12 pregnant camels and G3 consists of 12 young males and females. We confirm that we followed international standards for research animal ethical protection. The samples were taken during the wet and dry seasons. Blood was drawn from the jugular veins of the animals. The centrifugation (3000 rpm/ 20 minutes) was used to separate the blood plasma sample from the serum (Abd El-Salaam and Arafa, 2018; Hamad et al., 2018; Mohammed et al., 2021).
       
The samples were placed on ice at about -18^oC and transported to the laboratory for biochemical analysis on the same day. Several biochemical parameters, including serum glucose, triglyceride, cholesterol, urea, serum creatinine and total protein, were measured using commercial diagnostic kits (MINDRAY BA-88A Semi-Auto Chemistry Analyser) (Adjorlolo et al., 2019).
       
The data were analysed using statistical analysis software (SAS, version 9.0) in accordance with multivariate analysis protocols. Means and standard error of mean were used to present the data. The means of various age groups and productive/reproductive statuses were compared using an analysis of variance (ANOVA). The statistical means of two seasons (dry and wet) and settings (arid and semi-arid) were compared using the independent-samples approach. The overall level of statistical significance for the ANOVA and t-test was set at P < 0.05.
   
Where,
α_i = The i^th effect of season (i=1,2).
β_j = The j^th effect of environment/agro- ecology (j=1, 2).
γ_k = The k^th effect of age of camels (k= 1, 2, 3).
δ_l= The l^th effect of animal status(reproduction/production) (l= 1,2,3).

Effect of season on profiles of camels
 
Table 1 illustrates the effect of season on blood biochemical parameters of camels. The average concentrations of glucose, triglycerides and cholesterol during the rainy season are 91.33±7.30, 75.28±5.38 and 80.28±7.87, respectively. Glucose, total protein and triglyceride levels were higher in the rainy season than in the dry season (P<0.05), but cholesterol levels were not statistically significant (p<0.05). During the dry seasons, however, the mean values of total protein, urea and creatinine were 7.17 0.15, 32.0±61.18 and 2.06±0.05, respectively, the result is significantly higher than during the rainy season (P<0.05). This result is in line with those of Faraz et al., (2020), Worku et al., (2021) and Faraz et al., (2022), who revealed that camel nutritional status can be evaluated using biochemical parameters and that nutritional status changes by season and geographic location. Serum biochemical parameters (glucose, cholesterol and urea) varied significantly (P<0.05) between dry and rainy seasons. Aichouni et al., (2013) stated that seasonal fluctuations in triglyceride and cholesterol concentrations were found, but there was no effect on plasma glucose, serum urea, or creatinine concentrations. This findings is in line with Dar et al., (2019) Serum glucose levels and total proteins increase during rainy seasons, while serum, triglycerides, cholesterol, creatinine and urea levels decrease during dry seasons. Seasonal variations in biochemical levels are observed. However, no significant differences (P< 0.05) in biochemical parameters (total protein, albumin and globulin) were observed with respect to age, despite the fact that the highest values of all serum biochemical parameters were reported during the rainy and the lowest values during the dry (Jan and Ahmed, 2021).
       
Worku et al., (2021) discovered that serum creatinine levels were higher (P<0.001) during the dry season than during the rainy season. According to Ocheja et al., (2021), levels of plasma proteins, glucose, total cholesterol, LDL cholesterol and BUN significantly decreased. Due to their propensity to recycle huge amounts of protein for internal use, camels may have higher blood levels of total urea. Serum creatinine and urea levels were higher (P<0.001) during the dry season than during the rainy season, but urea levels were lower, according to Worku et al., (2021) and Faraz et al., (2022). Heat stress can reduce nutrient intake, for example, accounts for approximately 35% of the decrease in milk yield in Holstein cows (Ocheja et al., 2021).
 

 
Effect of ages on serum parameters in browsing camels
 
The effects of age groups on the concentration of energy and protein parameters are shown in Table 2. In comparison to animals aged 5-8 and younger than 5 years, animals older than 8 years had higher mean concentrations of glucose, creatinine, triglycerides and cholesterol (P<0.05). This study showed greater levels of glucose (mg/dl) 87.46±12.13 in > 8-year-old camels, higher levels of total protein (mg/dl) 7.26±0.18 in < five-year-old camels, higher levels of triglycerides (mg/dl) 70.63±6.12 in > 8-year-old camels and higher cholesterol (mg/dl) 89.17±9.96 in > 8-year-old camels. This findings is in agreement with Sahraoui et al., (2016) who reported (mean and SE) an average serum glucose value of 5±2.11 mmol/L, urea and creatinine values of 2.6±0.72 mmol/L and 1±0.39 mmol/L, respectively and lipid values of total cholesterol (1 mmol/L), triglycerides (1 mmol/L) and LDL cholesterol (0.06±0.09 mmol/L). Age and breed all had an effect on blood biochemical markers (Nagy et al., 2014). This could support the hypothesis that aging and changes in nutrition have an effect on serum total protein (TP) concentrations and the majority of protein fractions. This finding is consistent with Elkhair (2019), who revealed haemoglobin variation with age in camels. Other researchers, on the other hand, found that glucose, urea, triglycerides and total cholesterol levels were significantly greater in young camel serum than in adult camel serum (Abdalmula et al., 2023) which is contradicting with these findings. Nollens et al., (2020) reported that age is a good variable to compare glucose levels in animals as an indicator of nutritional quality.
 

 
Effects of agro-ecological conditions on serum parameters in natural browsing camels
 
Table 3 shows the effects of agro- ecology (arid and semi-arid environments) on blood biochemical parameters in natural browsing camels in southern Ethiopia. Camel glucose, total protein, triglyceride and cholesterol levels were lower in arid areas than in semi-arid areas (P<0.05). Creatinine (1.86±0.04) and urea (28.28±1.70) serum concentrations were higher in arid camels than in semi-arid camels (P<0.05). These seasonal differences could be attributed to the dromedary camels’ increased energy consumption as a result of heat stress (Hoter et al., 2019; Tibary et al., 2020). Despite higher levels of creatinine, which indicate increased muscle breakdown, the same authors reported that during the dry season, less protein was available to support as an energy source. The findings corroborate the findings of Xulu et al., (2022), who revealed a link between total protein and creatinine levels.
 

 
Effects of production/reproduction status of camels on the serum parameters of browsing camels
 
The effects of animal productive state on blood biochemical parameters of browsing camels are presented in Table 4. Total protein had mean ± SEM values of 6.90±0.14, 6.57±0.17 and 7.26±0.18 in milking, pregnant and young camels, respectively. In comparison to immature camels, lactating and pregnant camels had considerably higher glucose concentrations (P<0.05). When compared to milking camels, the younger (non-lactating or pregnant) camels had significantly greater levels of cholesterol, triglycerides and total protein (P<0.05). When compared to pregnant or immature camels, milking camels had the lowest triglyceride and cholesterol values (P<0.05).
 

In this study, the impacts of season, agro ecology, age and animal productive condition on the biochemical of camels in natural browsing habitats are presented for the first time. The results of this study demonstrate that varied influences of season, environmental circumstances, age and animals’ production/reproduction status clearly altered measures of protein and energy. It was revealed that the blood’s biochemical characteristics fell short of the standard. The camel mostly survives due to its physiological adaptation to adverse climatic conditions, even though the observed values for energy and protein were below the threshold value for maintenance of camels. This may help to explain why camels in the study areas were producing even though they were solely reliant on natural browsing and did not get any supplemental nutrient-rich feed. Changes in dietary status may be responsible for the remarkable urea conversion of camels, which may have a significant positive influence in places with a feed shortage.