Performance and blood profile of Noiler chickens fed diets containing graded levels of Parkia biglobosa leaf meal

A study was undertaken for 56 days to determine the growth performance and blood profile of Noiler chicks fed diets with different levels of Parkia biglobosa leaf meal (PBLM) as a partial replacement of soya bean meal (SBM). A total of ninety - six unsexed Noiler day - old chicks were allotted into four dietary groups of 24 chicks with three replicates of eight per group based on weight equalization using a Completely Randomized experimental design. Group 1 containing 0% PBLM (control), groups 2 to 4 had SBM replaced at 5% 10% and 15% in their diets respectively. Data were collected on feed intake, weight gain, feed conversion ratio, feed cost reduction, haematological and serum indices. Results showed that PBLM had an effect (p<0.05) on the growth performance, feed cost reduction, and blood profiles. There was better performance up to 10% PBLM but the performance declined significantly at a higher inclusion level. There was an improvement in the haematological parameters up to 10% PBLM inclusion. The AST and ALP increased significantly with the increased level of PBLM while the total protein, albumin, cholesterol and glucose reduced with the increased level of PBLM: nevertheless, there were no influences (P > 0.05) on the protein and albumin values. The result of this study, therefore, suggested that soya bean meal in Noiler chick diets can be replaced by up to 10% of PBLM without harmful effects on the growth and blood profile.


Introduction
The poultry industry is the major competitor with human feed resources leading to an escalated cost of production (Chandrasekaran, 2014). The current trend in animal nutrition is having readily available alternatives, less competitive, low production cost, and poultry health -friendly (Iji et al., 2017;Tanimo et al., 2020).
WorldoMeter (2020) estimated Nigeria population to be 210,568,792 with an annual growth rate of 2.58%, therefore, there is a need to reduce the generation cycle of poultry production with the aim of achieving the animal protein requirement of the population. There is also a need for low-cost feed input and breed with high meat and egg production.
Noiler is a dual-purpose chicken breed developed in Nigeria by Amo Farm Sieberer Hatchery. This breed is easier to raise and manage, high survival rate has less susceptibility to diseases, is rugged in nature and is resistant to harsh weather conditions. They are affordable chicken breeds and cheaper to maintain. They can scavenge for food and water just like indigenous breeds.
Leaf meals have been recorded to have ample protein, vitamins and antioxidants (Rama Rao et al., 2019). The incorporation will reduce the dependency on expensive conventional protein sources and bring down the cost of production (Sugiharto et al., 2019). The presence of antioxidants and bioactive substances may improve the well-being and vitality of the chickens (Sugiharto et al., 2019). As reported by Sow et al. (2010), consumers have higher preference for meat from chickens fed with leaf meal because of the better organoleptic/sensory indices. Faustman et al. (2010) also reported that leaf meal incorporation in chicken diets improves the antioxidative status of the meat. Different species of green and leguminous vegetables are propagated over around 71.2 million hectares of arable land in Nigeria, and they can be used as a substitute for conventional protein resources (Essiet and Solomon, 2013). According to Ndelekwute et al. (2018) and Sugiharto et al. (2019), the major limiting factors to using leaf meals in poultry production are elevated fibre FULL PAPER content, anti-nutritive factors and poor palatability which can be resolved by the right processing methods (Martens et al., 2012). Blood profile is an excellent indicator of nutritional and physiological status (Peres et al., 2014;Etim et al., 2014), hence it should be considered when adding additional feed resources to livestock diets.
Parkia biglobosa tree is a deciduous plant in the Fabaceae family well distributed in the Tropics (Heymann et al., 2012). The tree is important for its fermentable seeds (Orwa et al., 2010), however, every part of the tree is important to humans, especially for medicinal and nutritional purposes (Di Cagno et al., 2016;Okpara and Ugwuanyi, 2017 (Soetan et al., 2014;Alalade et al., 2016;Afolayan et al., 2020).
There is a paucity of documented work on the use of P. biglobosa leaf meal in broiler diets. This study aimed at evaluating the effect of feeding P. biglobosa leaf on the performance and blood profile of Noiler chickens thereby increasing the available knowledge on both the P. biglobosa leaf and the Noiler birds.

Location of research
The feed trial was executed at Landmark University Teaching and Research farms, while the laboratory analyses were done at the Animal Science Nutrition Laboratory, Landmark University, Omu Aran, Kwara State, Nigeria for a period of 8 weeks.

Sources of ingredients
The P. biglobosa leaves were collected from Landmark University Teaching and Research Farm while other feed ingredients were procured from Omu Aran town.

Parkia biglobosa leaf meal preparation
To avoid losing some critical nutrients, P. biglobosa leaves were harvested and air-dried to equal weight with the greenish colour intact. The air-dried leaves were ground (3 mm sieve size) and stored in sealed plastic buckets until they were added to the feed.

Experimental design and animal management
A total of ninety-six unsexed Noiler day-old chicks were sourced from Amo farm, Awe, Oyo State, Nigeria. The chicks were randomly assigned to one of four nutritional treatments based on their weight, with each treatment group consisting of three replicates of eight chicks in a completely randomized experimental design. Diet 1 had 0% P. biglobosa leaf inclusion (control) while diets 2, 3 and 4 had the inclusion of the test ingredient at graded levels of 5%, 10% and 15% respectively. The chicks were grown in a traditional open-sided deep litter house that was kept clean. Throughout the experiment, the animals were fed and watered as needed, and their medication and vaccination schedules were adhered to. Standard ethical and animal welfare guidelines were strictly followed throughout the project. The birds had full access to the experimental foods and clean water during the feeding study. The diets (Table 1)  The dry matter, moisture, crude protein (CP), crude fibre (CF), ether extract (EE), and ash of the P. biglobosa leaf were determined using AOAC (2014). Briefly, CP was determined by the Kjeldahl nitrogen (N) method and the CP was calculated with the formula: % CP = % N × 6.25 EE was determined with the Soxhlet method. 1g of the sample is carefully wrapped in Whatman filter paper and inserted into the Soxhlet tube that was 75% filled with petroleum ether for semi-continuous solvent extraction. This was boiled until a clear solution was observed. Ether extract content was measured by the weight loss of the sample. For ash determination, 1 g of sample was weighed into the dried weighed crucibles. The crucible containing the sample was then transferred into the muffle furnace for 4 hrs at 550 o C. Ash content was calculated thus:

Performance characteristics
Feed intake (daily) and weight gain (weekly) were taken which were then used to calculate the feed conversion ratio (FCR) as shown below:

Haematological and biochemical parameters
Two sets of blood samples were obtained from the brachial veins at the end of the feed trial. Blood for haematological indices was drawn from each replicate using aseptic syringes and needles and placed in EDTAcoated bottles before being processed on an automated Mindray BC 2800. The erythrocyte indices (mean corpuscular haemoglobin, mean corpuscular volume, and mean corpuscular haemoglobin concentration) were calculated using the packed cell volume (PCV), haemoglobin (Hb), and red blood count (RBC).
The MCV shows the mean red cell volume measured in cubic micron (µ 3 ).
MCH shows the amount of Hb per cell expressed in picogram (pg).
MCHC is the concentration of Hb in the RBC juxtaposed with the concentration of Hb in 100 mL of whole blood expressed in percentage.
For the biochemical indices, the second set of blood was collected into plain sample bottles with the aid of the colourimetric method from the specific reagent kits with BIOBASE BK-F96PRO spectrophotometer.

Economy of production
The feed cost reduction of replacing the SBM with PBLM was calculated. Other expenses on drugs, vaccines and litter were common for all the treatments.

Statistical analysis
All the generated data were analyzed via One-Way Analysis of Variance (ANOVA) using SPSS version 13 edition (SPSS, 2006). The means were separated using Duncan Multiple Range Test.

Proximate components of Parkia biglobosa leaf meal
The proximate components of PBLM (Table 2) demonstrate that the CP, CF, EE, and ash values obtained in this investigation were lower than those obtained by Soetan et al. (2014) but higher than those reported by Alalade et al. (2016). These differences may be due to the age and variety of the leaves, geographical location, climate and methodologies and instruments used. In comparison to some other leaf meals that have been successfully used in the poultry industry, the PBLM shows very good nutritive potential. The CP from the study at hand is higher than those of the moringa and scent leaves (Mahima et al., 2014;Okunlola et al., 2019). However, the CP in this study is lower than those of centrosema, bitter leaf and syndrenella leaf (Nworgu and Fasogbon, 2007;Okunlola et al., 2019;Suwignyo et al., 2020). For the EE, the value in PBLM is higher than those of centrosema, moringa and scent leaves (Nworgu and Fasogbon, 2007;Mahima et al., 2014;Okunlola et al., 2019) but lower than those of bitter leaf (Okunlola et al., 2019) and syndrenella (Suwignyo et al., 2020). The ash value for PBLM in this study is higher than the stated values for syndrenella, bitter leaf, centrosema and moringa leaves. This connotes that PBLM has the potential to be used in poultry feed.

Parameters
Values (

Growth performance
As indicated in Table 3, the inclusion of P. biglobosa influenced (P < 0.05) the growth performance traits with the exemption of feed conversion ratio. This is similar to Ani et al. (2013) who included Gongronema latifolium leaf in the broiler chickens' diet. Higher feed intake was observed as the level of the test ingredient increased. It may be due to the reduction of CP level as the test ingredient increased. This finding backs up the findings of Kakengi et al. (2007), who found increased feed consumption in egg-typed chickens fed diets containing up to 20% Moringa leaf. Broilers fed diets containing up to 10% Ipomoea asarifolia leaf consumed more feed (Ekenyem and Madubuike (2006). However, the findings of this study differ from those of Tokofai et al. (2021), who found a decrease in feed intake when Vernonia amygdalina leaf meal was fed to broiler chicks, which he attributed to the bitterness of the leaf meal.
The weight gain increased as the P. biglobosa increased in the diet up to 10% inclusion level then drop at the 15% inclusion level. The highest weight gain (14.57 g/bird/day) and the best FCR (2.24) were observed at the 10% inclusion level. Tokofai et al. (2021) found that including Vernonia amygdalina leaf meal improved weight gain and FCR at all levels. Oghenebrorhie and Oghenesuvwe (2016) discovered a similar trend in broiler hens fed moringa leaf diet. However, the former and latter authors' inclusion rates of 1-3% and 1-8%, respectively, are lower than those employed in the current study (5 -15%). The drastic drop in the weight gain at 15% of P. biglobosa leaf might be a result of the high level of an anti-nutritional factor at that level of inclusion (Erdaw and Beyene, 2019). Ramah et al. (2020) reported that high tannin group chickens had decreased daily gain, final body weight, daily feed intake and relative weights of lymphoid organs. It could also be due to the higher fibre content of the diets at 15% PBLM which might have impaired nutrient digestibility and absorption (Lattimer and Haub, 2010). This result showed that inclusion levels up to 10% of PBLM, resulted in better performance of the chicken while the growth performance was adversely affected at a higher level.

Haematological Indices
One of the most effective ways to evaluate the health status of animals is through haematological indices (Oloruntola et al., 2015). A haematological analysis is necessary to assess the suitability and quality of the novel non-conventional feed ingredients for the animal before they are incorporated into the feed (Attia et al., 2018).
The result of haematological parameters (Table 4) shows that the indices were affected (P < 0.05) by the inclusion of PBLM in the feed while the MCV and MCHC were not affected (P > 0.05) by P. biglobosa leaves in the feed.
The highest values for most of the haematological indices were observed at 10% PBLM inclusion, while the highest values for all the erythrocytes indices were observed at 5% PBLM inclusion. The generally higher values of haematological indices observed in PBLM chickens are indicative of better utilization, absorption and assimilation of the nutrients into the circulatory system of the chickens (Onu, 2010). The above observation is similar to that of Basit et al. (2020). All the values obtained for MCV and MCHC were statistically similar irrespective of the inclusion level of the PBLM in the diets. At 10% PBLM inclusion, the highest values for most haematological indices were recorded, while at 5% PBLM inclusion, the highest values for all erythrocyte indices were observed. The values for all the haematological and erythrocyte indices obtained in the study at hand fell within the acceptable levels for healthy chickens as reported by Bounous and Stedman (2000) and Okeudo et al. (2003) Previous workers had earlier reported that incorporating leaf meals into poultry diets enhances the haematological indices of the birds (Abbas et al., Basit et al., 2020), however, Odetola et al. (2012) and Tijani et al. (2015) observed a reduction in the haematological indices of chickens fed moringa containing diets. The results of this study tend to suggest that P. biglobosa leaf possesses such "blood tonic effects" and supports haematopoiesis which may be due to its high content of minerals and vitamins (Olumide et al., 2018). Olugbemi et al. (2010), reported that RBC is responsible for the transportation of CO 2 and O 2 in the blood and also manufactures Hb. Therefore, higher values in the birds fed PBLM indicate a greater potential for this function and a better state of health. PBLM had no effect (P > 0.05) on PCV values between the control diets and those fed diets 2 and 3 (5% and 10% PBLM groups), although the values generally increased numerically with the increased PBLM level. This may indicate the absence of toxic factors in the PBLM as haematocrit (PCV) is an index of toxicity (Onu and Aniebo, 2011).
The WBC count in birds fed PBLM (with the exception of the 5% PBLM inclusion level) was equivalent to the WBC count in birds fed a control diet. The inclusion of P. biglobosa leaves in this study may thus indicate that the animal's health and ability to combat illness were not jeopardized (Oloruntola et al., 2018). Previous workers have attributed the variations in avian haematological blood values to the physiological condition of the birds (Islam et al., 2004;Attia et al., 2015).

Serum biochemical indices
From the result of biochemical indices shown in Table 5, the PBLM in the diet affected (P<0.05) the AST and ALP, glucose and serum cholesterol while the total protein and serum albumin were not (P>0.05) affected. There is no particular trend in the effect of the test ingredients on the serum biochemical indices analyzed. The liver possesses enzymes to carry out its functions of detoxification and elimination of harmful substances from the body. These enzymes (ALT, ALP and AST) are important in the determination of the proper functioning of the liver (Ambrosy et al., 2015). Pathological and or impaired cells or tissues may lead to the elevated concentration of liver enzymes (Giannini et al., 2005). Hepatopathies, according to Giannini et al. (2005), can have biochemical manifestations such as high AST and ALT levels, as well as moderate abnormalities inglutamyl transpeptidase and ALP levels.
ALP is a homodimeric enzyme that participates in bile production while AST concentration gives the picture of the hepatocyte integrity. Generally, the inclusion of the PBLM tends to increase the AST and ALP, though the lowest values were observed at 15% PBLM inclusion. This correlates with the report of Basit et al. (2020). The values of AST and ALP obtained in Parameters   FULL PAPER the current study are lower than the limit obtained by Meluzzi et al. (1992) but higher than those observed by Tijani et al. (2015) who observed a reduction in the AST of birds fed diets containing moringa leaf meal. However, the values of ALP in this present study were similar to those of Odunitan-Wayas et al. (2018).
Dietary protein has been shown to have an impact on total protein and its components (Obikaonu et al., 2012). The test ingredient in this study did not affect (P > 0.5) the total protein and albumin, but generally, the values reduced as PBLM increased in the diets. The reduction in the protein and its fraction could be a result of the antinutrients in the test ingredient (Odetola et al., 2012). The total protein and serum albumin, on the other hand, were within normal levels for hens (Meluzzi et al., 1992). The observations in this present study for protein and serum albumin were similar to observations by Obikaonu et al. (2012) and Tijani et al. (2015) who incorporated neem and moringa leaves respectively into broiler diets. Basit et al. (2020) and Tokofai et al. (2021), who showed that broiler chicken fed Persicaia odorata leaf meal had greater total protein and serum albumin levels, disagree with the current finding. The factor responsible for these differences could be the different types of leaves used in the studies.
The inclusion of PBLM has an irregular effect on serum cholesterol, but it is generally reduced (P < 0.05) as PBLM increases. This supports the findings of Alnidawi et al. (2017) and Abbas et al. (2018), who found that increasing moringa levels in poultry diets lowers total cholesterol. The efficacy of bitter leaf meal to lower cholesterol was reported by Owen and Amakiri (2011) and Tokofai et al. (2021). The test ingredient may increase the activity of the enzyme catalase, which is required for cholesterol esterification, resulting in lower serum cholesterol in chicken given PBLM.
A high level of cholesterol is risky and a predisposing factor to cardiovascular disease. The values of serum cholesterol in this study fall within 87-192 mg/ m reported for chickens (Meluzzi et al., 1992). This also means that the inclusion of PBLM inclusion in Noiler diets will not impair the reproductive, adrenal and nervous tissues. Apart from the fact that cholesterol is a major component of the nervous tissue, its role as a vital constituent of adrenal hormones and pituitary hormones cannot be overemphasized.
Similar to the observation in the cholesterol level, PBLM in the Noiler chicken diets reduced the glucose level. This contradicts Obikaonu et al. (2012)'s findings that neem leaf meal induces hyperglycemia, but it agrees with Basit et al. (2020)'s findings that broiler hens fed Moringa oleifera leaf meal has higher levels of AST, ALP, glucose, and cholesterol.

Economy of PBLM inclusion in the diets
The result of the evaluation of the economy of production, specifically the feed cost reduction is shown in Figure 1. As the number of test ingredients increased, the cost of making a kilogramme of feed decreased. This is consistent with past research that has used alternative feed additives. (Nworgu et al., 2015). Also, an increase in the level of PBLM in the diets decreased the feed cost per kilogram of weight gain. Similar to the trend in the growth performance, feed cost reduction per kg weight gain was highest at 10% PBLM. The fall in the feed cost reduction per kg weight gain at 15% level could be due to higher feed intake at this level which consequently erased the benefit of the low cost of feed per kg (Nworgu et al., 2015).

Conclusion
From this study, P. biglobosa leaf meal can be included in Noiler chicks' diets up to 10% for improved growth performance, feed conversion ratio, and feed cost reduction without hampering the haematological and serum biochemistry of the chicks. It is recommended that further study should be carried out on the fermentation process to alleviate the effect of anti-nutritive factors in the leaf.

Conflict of interest
The authors declare no conflict of interest.