Utilization of Processed Kola Nut Husk Meal in Poultry Production: Effects on The Performance, Carcass, Biochemical Indicators, and Antioxidant Enzymes of Broiler Chickens

This study looked at the effects of processed kola nut husks meal (PKHM) utilization as a feed ingredient on broiler chicken in a 42-day feeding trial. Kola nut pod husks were processed into a PKHM using ash treatment and rumen liquor fermentation. Three experimental diets were developed at both the starter and finisher phases, with PKHM included at 0, 4, and 8%, and dubbed diets 1, 2, and 3, respectively. In a fully randomized design, 240 Arbor Acres broiler chicks were randomly assigned to three treatments (10 birds per replicate). Except for the significantly improved (P < 0.05) feed conversion ratio of broiler chickens fed diets 2 and 3 at the grower phase (22–42 days) and overall (0–42 days), the performance indices were not significantly (P > 0.05) affected by PKHM dietary inclusion. Broiler chicken carcass characteristics and relative internal organ weights remained constant (P > 0.05) through diets. The serum glutathione concentration in broiler chickens fed an 8 percent PKHM inclusive diet increased significantly (P < 0.05) than those on the control diet and 4 percent PKHM inclusive diet. When broiler chickens fed an 8 percent PKHM inclusive diet were compared to those fed a control diet, the serum catalase concentration was significantly higher (P < 0.05). The total serum protein, creatinine, alanine aminotransferase, aspartate transferase, and cholesterol levels remained constant (P > 0.05) regardless of dietary treatment. Dietary PKHM inclusion of up to 8% enhanced improved feed efficiency and increased antioxidant enzyme concentration and did not affect the serum biochemical indices concentration.


Introduction
Environmental contamination from excessive agro-waste disposal and low animal protein consumption due to high animal protein costs are two of the most challenging problems in developing countries [1,2]. Agricultural operations produce agro-waste, making the environment squalid and polluting the atmosphere if it is not correctly disposed of or used productively [3]. Mainly, kola nut husk, cattle, and poultry wastes, among others, are essential components of agro wastes. If not adequately disposed of or utilized for productive purposes, it could constitute a nuisance to the environment [2][3][4].
A vast number of these agro wastes such as cassava peel [5], cocoa pod husk [4], cocoa bean shell meal [6,7], cassava starch residue [8], rumen content, and poultry wastes [2] were reported to be helpful as replacements for conventional feed ingredients in monogastric animal production.
Kolanut (Cola acuminata), a small tropical evergreen African tree, has a global output of 300,000 tons. The kola nut husk, which was previously considered waste, contains 130 g of crude protein per kilogram, 71.3 g of crude fiber per kilogram, and 2546.9 cal per kilogram of gross energy [1,9]. Kolanut husk, derived from processed kola nut fruits, is another useful agricultural waste product used to substitute maize in poultry feed production [9,10]. Kola nut husk was reported to contain some bioflavonoids, which can help in enhancing growth [10]. As a result, kola nut husk may be a good substitute for maize in broiler chicken diets, lowering environmental fouling and reducing livestock feeding costs [5,9,11].
However, the anti-nutritional factors could deter nutritional availability in agro-waste such as kola nut husk, particularly when not adequately subjected to proper processing methods [9,12]. In a previous study, increased levels (0, 5, 10, 15, and 20%) of kola nut husk in broiler chicken diets inhibited growth [11]. Nevertheless, the nutrient and the phytochemical composition of kola nut husk can be improved when subjected to one or a combination of processing methods [4,13], such as fermentation [2], alkaline, and urea treatment [14]. As earlier reported by Adeyeye et al. [4], the combination of ash treatment and rumen liquor fermentation improves the nutritional profile of cocoa pod husk, making it suitable for broiler chickens diet up to 8% inclusion level. It is rare to see kola nut husk treated with ash and rumen liquor fermentation, then used in broiler chicken output. As a result, this study aims to see how broiler chicken performance, carcass traits, serum antioxidant enzymes, and serum biochemistry indices are affected by dietary inclusion of kola nut husk meal that has been ash treated and rumen liquor fermented.

Study Site and Ethical Approval
The Department of Animal Health and Production Technology, The Federal College of Agriculture, Akure (FCAA), Research and Moral code Committee, ratified all experimental animal protocols for this research. The study was executed at The FCAA Research Farm [15].

Kola Nut Husk Meal Processing
As earlier described by Adeyeye et al. [15], kola nut husk was collected and altered into kola nut husk meal (KHM). The dried corn stalks were burnt to corn stalk ash. The corn stalk ash extract was then prepared according to Adeyeye et al. [15]. Using a cheesecloth, bovine rumen liquor was extracted from the rumen matter of recently butchered cattle and used right away. Sun-dried layer bird droppings were collected, ground, and stored in bags until they were required. Molasses was bought in Akure, Nigeria, from a well-known commercial animal feed mill.
Kola nut husk meal was processed using the duet processing techniques of ash treatment and solid-state fermentation with the rumen liquor in this research [13,15]. In a black plastic vessel, the kola nut husk meal was meticulously mixed with corn stalk ash extract at 188 g per liter and held in an anaerobic condition for a week. The kola nut husk meal that had been immersed in corn stalk ash extract was then drained, sunbaked for fourteen days, and tabbed the ash-treated kola nut husk meal.
The ash-treated kola nut husk meal was further subjected to rumen liquor fermentation [16] and was consecutively mixed with the 100 g/kg layer droppings and 50 ml/kg molasses. After that, the blend of ash treated kola nut husk meal, layer droppings, and molasses were showered with the newly collected bovine rumen liquor in a black plastic vessel and let to ferment anaerobically for a week. Subsequently, the fermented kola nut husk meal was sunbaked for seven days, explored for tannin [17], caffeine [18], theobromine [19], proximate composition [20], and after that tabbed processed kola nut husk meal (PKHM).

Treatments and Experimental Design
For the starter (1-21 days) and finisher (22-42 days) production phases of the experimental birds, three experimental diets were developed (Table 1), with PKHM included at 0% (diet 1), 4% (diet 2), and 8% (diet 3). Two hundred and forty 1-day old Arbor Acres broiler chicks were haphazardly apportioned to three diets (10 birds/replicate; 8 replicate/ treatment) in a completely randomized design (CRD). The birds in each replicate were confined in a 200 × 100 cm pen for the first week at a temperature of 31 °C ± 2, which was gradually reduced by 2 °C each week until the temperature reached 26 °C ± 2. Luminance was given for a total of 23 h per day. Throughout the experiment, the birds were given unlimited amounts of water and mash.

Performance of Chickens, Slaughtering, Sample Selection, and Analysis
The birds' body weight (BW) and their feed intake (FI) were taken at a seven-day interval. After that, the birds' body weights gain (BWG) was calculated as the differences between the final weight and the initial weight [4]. The feed conversion ratio (FCR) was calculated as the ratio of feed consumed to the weight gain [4].
At the end of the sixth week of the experiment, three birds per replication were hand-picked, labelled, weighed, and slaughtered by lacerating the experimental birds' jugular veins after stunning [4]. The blood was allowed to flow into a plain sample collection bottle before centrifuging; the serum was then isolated and stored at − 20 °C for analysis [4]. The catalase (CAT) activity was determined using the method early described by Sinha, [21] while the serum glutathione peroxidase (GPx) was determined using the method described by Rotruck et al. [22]. A Reflectron ® Plus 8C79 (Roche Diagnostic, GombH Mannheim, Germany) was used to measure total protein, alanine aminotransferase (ALT), cholesterol, and aspartate aminotransferase (AST). After de-feathering, evisceration, and dressing, the birds' slaughtered weights and dressed percentages were determined. The liver, kidney, heart, lung, spleen, pancreas, kidney, gall bladder, and gizzard of the birds were excised, weighed, and expressed as a percentage of the slaughtered weight.
The price of feed ingredients at the time of the experiment was used to determine the cost of making the experimental diets. The cost of feed consumed was calculated by multiplying the cost of one kilogram of the diet by the total amount (in kilogram) of feed consumed.
Relative cost-benefit (%) is the difference between the cost of feed (₦/kg) per weight gain (kg) of control diet and cost of feed (₦/kg) per weight gain of test diet divided by the cost of feed (₦/kg) per weight gain (kg) of control diet multiply by 100.

Analysis of Data
The model: V ab = m + e d + β rh was adopted in this study. The V ab = any of the reaction variables; m = the complete mean; e r = effect of the dth treatment (d = diets 1, 2, and 3) and β gh = random error due to experimentation. SPSS version 20 was used to perform a one-way analysis of variance on the results. Duncan's multiple range test of the same package was used to assess the variations between means [23].

Cost of feed per kg body weight gain =
Cost of 1 kg feed × kg of feed consumed Total weigth gain(in kg)

Composition of Processed Kola Nut Husk Meal
The phytochemical compositions of processed kola nut pod husk meal (PKHM) are shown in Fig. 1. Compared to other indices such as crude protein, crude fiber, crude ash, and ether extract, the composition analysis demonstrates that PKMH has relatively high crude protein and nitrogen-free extract. PKHM also contains caffeine, theobromine, saponin, and tannin.

Performance and Carcass Traits of Broiler Chickens fed PKHM Inclusive Diets
The effects of PKHM on broiler chicken performance are shown in Table 2. Except for the significantly improved (P < 0.05) feed conversion ratio recorded in broiler chickens fed diets 2 and 3 at the grower phase and overall, the performance indices were not significantly (P > 0.05) affected by PKHM dietary inclusion. The similar body weight gain in the experimental birds across the various dietary treatments in this study suggests that PKHM has akin nutritional attributes to the regular or standard ones and holds up the expected growth performance in broiler chicken.
It was previously stated that agrowastes could be a good feed ingredient in monogastric animal production if appropriately processed [3,8,24]. This study's growth performance results contradict earlier reports by Fabunmi et al. [9], who found that kola nut husk added to broiler diets at 10%, 30%, and 50% with or without enzyme supplementation caused poor growth. However, the encouraging growth observed in the experimental birds fed PKHM in this study suggests that the processing methods used for the kola nut husk and the inclusion levels are relevant and practical. It has been suggested that agrowastes be processed to reduce or eliminate anti-nutrient interference with nutrient absorption at dangerously high concentrations [2,24]. The feed conversion ratio, a pivotal factor for estimating feed efficiency in broiler production, is affected by feed quality [25]. Therefore, the improved feed conversion ratio recorded at the grower phase (22-42 days) and overall (0-42 days) in the broiler chickens fed PKMH inclusive diets further suggest that the test ingredient used did not compromise but instead improved the general quality of the experimental diet to favor the better conversion of feed to live weight. From another side, it was observed that the FCR of the birds at the starter phase was high. This observation cut across the entire treatment groups in this study implies that the cause is outside the dietary treatment being studied in the trial. Therefore, environmental conditions predisposing the birds to heat stress, particularly during the post brooding period, could have been responsible. Heat stress alters the regular feed intake, protein synthesis efficiency, carbohydrates metabolism and increases oxidative stress in broiler chickens [26].
Nutriment has a notable influence on the yield of highquality meat from animals. Their relative organ weights are beneficial in predicting the harmful effects of test materials or diets [27,28]. Furthermore, toxins in the diet may be consumed and stored in different target tissues or organs, causing cell damage and altering healthy function and structure [4]. In this study, the broiler chicken carcass characteristics and relative internal organ weights remained constant (P > 0.05) through dietary treatments (Table 3). This observation indicates that the phytochemicals in the test ingredient are at a safe level and have not caused any noticeable adverse effects. The PKHM has not harmed the development of the birds' consumable parts typical structure. The activity of phytochemicals in stabilizing or producing favorable effects on carcass was reported by Valenzuela-Grijalva et al. [29].

The Serum Antioxidant Enzymes of Broiler Chickens Fed the PKHM Inclusive Diets
The consequences of PKHM on serum antioxidant enzymes and serum biochemical constituents are revealed in Table 4. The serum glutathione concentration in broiler chickens fed an 8 percent PKHM inclusive diet increased significantly (P < 0.05) than those on the control diet and 4 percent PKHM inclusive diet. The increased serum antioxidant enzymes recorded in the experimental birds fed 8 percent PKHM inclusive diets in this study suggest the test ingredient has phytochemicals that have antioxidant activity [30,31]. By interacting with free radicals during the oxidative phase, these phytochemicals with antioxidant properties help reduce oxidation [32]. Antioxidant enzymes such as catalase and glutathione peroxidase in the blood protect cells from the damaging effects of reactive oxygen species [33]. In addition, antioxidants help protect macromolecules like proteins, nucleic acids, and lipids from oxidative damage by scavenging free radicals produced by biochemical reactions [31]. Catalase protects cells from peroxide toxicity and hydrogen lipid peroxidation. In addition, glutathione peroxidase protects cells from the harmful effects of oxidation by catalyzing the degradation of numerous peroxidases and oxidizing glutathione [3,33]. In this study, when broiler chickens fed an 8 percent PKHM inclusive diet were compared to those fed a control diet, the serum catalase concentration was significantly higher (P < 0.05). This is of benefit and further unveils the antioxidant activity of PKHM.

The Serum Biochemical Parameters of Broiler Chickens Fed the PKHM Inclusive Diets
Serum biochemistry is helpful for disease diagnosis for livestock animals because they reflect their health condition [34]. The serum's total protein, creatinine, alanine aminotransferase, aspartate transferase, and cholesterol levels remained constant (P > 0.05) regardless of dietary treatment. The serum total protein concentration is commonly used to assess nutrition [35], while serum creatinine is a renal function indicator [36]. Alanine aminotransferase is a valuable enzyme for detecting liver damage [37], while cellular damage is indicated by an abnormally high level of aspartate transferase [38]. Arteriosclerosis is more likely in animals with elevated serum cholesterol levels [33]. Therefore, similar serum concentration levels of total serum protein, creatinine, alanine aminotransferase, aspartate transferase, and cholesterol recorded in the experimental birds across all the dietary treatments further support the wholesomeness of PKHM and its level of dietary inclusion adopted in this study. Table 5 demonstrates that the experimental diet 3 (8% PKHM) had the lowest cost per kilogram. In addition, the cost of feed per kilogram of weight gain and the relative cost-benefit percentage in the 4 percent and 8 percent PKHM inclusive diets were lower than the control diet. This means that for every kilogram of compounded broiler chicken feeds containing 4% and/or 8% PKHM, around ₦10.00 is saved. A tonne of feed can save up to ₦10,000,000.00. This finding backs up previous claims that processed agrowastes are suitable for poultry production [2,4,39,40].

Conclusions
In conclusion, dietary inclusion of PKHM up to 8% improved feed efficiency, did not affect serum biochemical indices, but increased serum glutathione level in broiler chickens by 17.34%. The relative cost-benefit of broiler chicken production increased by 10.47 percent and 10.35 percent, respectively, due to PKHM inclusion levels of 4 percent and 8 percent. As a result, broiler chickens can tolerate a dietary inclusion level of up to 8% PKHM.