Haemato-biochemical indices and immune response of grower pigs fed enzyme supplemented dried cassava peel and maize cob composite meal

,


Introduction
Worldwide population growth, rising incomes and urbanization are triggering an explosion in the demand for high quality protein.By 2030, the World Health Organization (WHO) projects annual meat production to reach 376 million tons globally up from 218 million tons in 1997-1999(Dan, 2021)).One of the major constraints of the development of livestock industry in developing countries including Nigeria is the high cost of conventional feedstuffs (Odunsi et al., 2013) due to stiff competition between human and animals.Maize constitutes about 60% of feed which also serves as food for many households in Nigeria (Kosemani;Bangboye, 2021).The according by Kosemani & Bamgboye (2021), maize culture is a major staple, fodder, energy plant, and model plant produced in sub-Saharan Africa, most notably in Nigeria.Competition between man and livestock for maize, soya beans among others is often responsible for high cost of these ingredients (Oladunjoye et al., 2005).
Several studies have been carried out on many energies supplying agricultural products as substitute for maize in swine feed.Among such products that have been tried are sweet potatoes, cocoyam, yam, rice by-products, peels of tubers, molasses, sorghum and wheat (Oladunjoye et al., 2017).One of such agro-industrial by-products is cassava peels and maize cob which are cheaper unconventional alternative feed resources for livestock animals (Anuore et al., 2024).
Cassava peel has to be processed to reduce the toxicity caused by some of its content and this content includes hydrocyanic acid (HCN) which is harmful to animals.Cassava is processed by various methods to increase acceptability and palatability by animals.Several processing methods have been applied over the years.Cassava peel can be processed using any of the following methods: grating and sun-drying, boiling, parboiling and sun-drying (Salami; Odunsi, 2003).According to Oladimeji et al. (2022), dry cassava peel after processing contains a significant protein content (3.66 g/100 g), crude fiber (9.40 g/100 g), ether extract (1.37 g/100 g), neutral detergent fiber (27.78 g/100 g), hemicellulose (17.73 g/100 g) and cellulose.Cassava peel is a potential nutritional source for use in feed, as observed in the study by Oladimeji et al. (2022).
Studies have also revealed that cassava peel and maize cob mixture can be used to replace maize up to 30% in the diet of weaner pigs without causing any negative effect on their performance (Anuore et al., 2024).Ojediran et al. (2019), also reported a non-significant difference in blood parameters of growing pigs fed cassava peel at 50% replacement.There is a direct relationship between nutrition and blood parameters (Shittu et al., 2021).However, there is scanty information on the use of cassava peel/maize cob meal mixture in grower pigs.A timely, evaluation will give a clue on the optimum replacement level and also help to use cassava peel/maize cob meal mixture to bridge the gap between livestock production and sustainability.
Therefore, this research was designed to examine the haemato-biochemical indices and immune response of grower pigs fed enzyme supplemented dried cassava peel maize cob composite meal.

Experimental site
This study was conducted at the University of Abuja Teaching and Research Farm, Main Campus, along Airport Road, Gwagwalada, Abuja, Nigeria; the Department of Animal Science, Faculty of Agriculture.Gwagwalada, situated between latitudes 8o571 and 8o551N and longitudes 7o051 and 7o061E, serves as the headquarters of the Gwagwalada Area Council (NPC, 2006).

Obtaining and getting ready test materials
Fresh maize cobs and cassava peels were gathered from several Gwagwalada cassava/maize processing facilities.For a duration of 16 days, the samples were exposed to sunlight in order to lower their anti-nutritional factor levels and prevent microbial responses that could cause spoiling and nutrient leaching.After being individually ground into meals in a hammer mill and treated with a multi-enzyme before it was mixed with other ingredients.
Samples of each meal was taken into the laboratory for additional examination.

Experimental animals, design and management
Thirty-six male large white grower pigs, aged 16 weeks, were purchased from a well-known farm in Abuja.The animals were kept in quarantine for a period of two weeks, fed a basal diet designed to satisfy the needs of grower pigs in accordance with the NRC's ( 2002) recommendation, and given preventive treatment, which included injections of long-acting Oxytetracycline at a rate of 2 mL/20 kg -1 body weight and subcutaneous Ivermectin® at a rate of 0.5 mL/25 kg -1 of body weight to control ecto and endo parasites.Pigs were divided into four treatment groups according to body weight, and each treatment was fully randomized and repeated three times with three animals in each replicate.Feeding was place twice a day at 8:00 and 16:00, and everyday access to fresh, clean water was provided.Daily feed intake was calculated by subtracting the left over from the feed supplied while the weight was taken weekly.All other management procedures were rigorously followed during the three-month duration of the investigation.

Blood collection and analysis
Two pigs per replicate making a total of six pigs per treatment were chosen on the 12th day of the experiment for hemo-biochemical measurement.During the blood collection process, a stress-free environment was maintained for a selected group of animals to avoid deoxygenating the oxygenated blood.The pigs under study had their jugular veins bled in order to extract 4 millilitres of blood per animal.Of this volume, 2 millilitres were placed in a bijou bottle and subjected to ethylene diamine tetra acetate treatment for haematological testing, while the remaining 2 millilitres were utilised for serum analysis.The Sysmex XN-3100 automated analyzer equipment was utilised to perform haematological analysis on red blood cells, haemoglobin, packed cell volume, white blood cells, and their respective differentials.

Immunological status estimation
The blood specimens utilized for haematological examination were used to perform immune-globulin (A, G, and M) activities.The MAGICL 6000 chemilum immunoassay analyzer, made in China, was used for the analysis.Samples were organised in the sample chamber and the temperature was adjusted to 32 ºC.The monitor (output unit) showed the findings of each parameter.Technical information included in the commercial kit includes the following information: technique (fluorescence enzyme immunoassay); detection (LED illuminant, non-flow cell); reaction time (antigen antibody reaction: 10 minutes); highest sample load limit (25 samples); sample container (primary tube, 13 × 75/100 mm, 16 × 75/100 mm diameter); temperature (15-30 ºC); and humidity (40-80%).

Phytochemical analysis in test ingredients
Concentrations of phytochemicals in maize cob and cassava peel were determined using standard procedures outlined by Sofowora (2009).

Statistical analysis
Data collected from the study was subjected to analysis of variance (ANOVA) using the computer software package SPSS 22.0; differences among treatment means were compared with Duncan's multiple range test (Duncan, 1995).
The cyanide content 15.03 mg/g -1 recorded in this study is within the tolerable range 50.00 mg/kg -1 for monogastric animal reported by Okoli et al. (2012).Alkaloids, flavonoids, tannins, saponins and phenols have different therapeutic properties such as, analgesics, antimicrobial, anti-inflammatory, antioxidant, hepato-protective, immune-stimualatory activities amongst others (Daniel et al., 2023).Heamatological values could serve as base line information for comparison in condition of nutrient deficiency, physiology and health status of farm animals (Daramola et al., 2005).The results obtained in this study shows that the dietary treatment had significant (p ˂ 0.05) effect on all the observed hematological parameters of growing pigs.Togun et al. (2007) state that when an animal's haematological values are within the normal range that has been defined for it, there was no negative effect of the diet during the trial period.In terms of trend, the PCV was greater in T4, closely followed by T3, T2, and T1 (control).The results are consistent with those of Adesehinwa et al. (2011), who observed that in growing pigs fed diets based on cassava peel meal (CPM) and CPM + Farmazyme-3000, the enzyme marginally increased PCV but not above that of a diet based on maize.
Increased cells destruction and subsequent enhanced erythropoiesis in the liver, spleen, and kidneys cause macrocytic (regenerative) anaemia, which is indicated by reductions in concentrations of erythrocyte parameters (e.g., packed cell volume (PCV), red blood cell counts (RBC), and haemoglobin (Hb) concentration) and elevations in MCV (Jain, 1986).The study's haemoglobin readings fell between the ideal ranges for developing pigs (Mercks Veterinary Manual, 2010).According to Merck's Veterinary Manual (2010), this further implies that the anti-nutritional components in cassava peel had been reduced to a manageable, non-fatal level, which explains why all the haematological measures were within normal limits.
This corroborates the findings of Maxwell et al. (2000a) who asserted that ingestion of dietary components had measurable effect on blood composition and may be considered as appropriate measure of long term nutritional status (Olabanji et al., 2007).Thus, everything that has an impact on blood, like diet, will undoubtedly have a negative or moderate effect on the body's overall health, growth, maintenance, and reproduction (Oke et al., 2007).According to Etim et al. (2014), there was a correlation between the nutritional state of animals and haematological features, specifically PCV and Hb.Even in cases when an animal did not exhibit overt clinical symptoms of illness, PCV and other haematological measures might be helpful prognostic tools and may indicate an unfavorable condition (Eze et al., 2010).
The fact that the concentration values of haematological features in this study did not fall below normal suggested that the minor amounts of anti-nutritional elements did not have a detrimental effect on these haematological parameters.The RBC concentration recorded in this study was similar to that of Enyenihi et al. (2008).The trend in the RBC, PCV and Hb in this study could be ascribed to the direct relationship among RBC, PCV and Hb (Jain, 1986).
The serum total protein and albumin of the growing pigs used in this study were affected (p ˂ 0.05) by the treatments.This indicated that the protein level in CPMCM was able to support the protein reserves of the pigs across the groups.The presence of variations in the serum metabolites could also be attributed to the protein and feed intakes across the groups.According to Gouache et al. (1991) and Alagbe (2017), a protein deficit has a particular impact on albumin content.The levels found in this investigation fell within the Adesehinwa (2007) normal range.The food therapy had no discernible effect on serum urea, an animal marker of muscle waste (Mitruka;Rawnsley, 1977).Rather, despite the diets' high fibre content, they appeared to have been used well, leading to substantial tissue deposition.
The results for creatinine, bilirubin, and cholesterol were all within the recommended ranges for pigs (Alagbe, 2024), indicating that there was no risk of renal failure or excessive fat content in the carcass of the animal.Elevated serum glucose level can be triggered during the period of stress or poor management (Shittu et al., 2023).ALT, AST and ALP values were within the normal range for healthy pigs (Merck Veterinary Manual, 2010), indicating the absence of liver or health issues (Olafadehan et al., 2023;Alagbe, 2024).The results revealed that there was significant difference (p ˂ 0.05) in all parameters among all dietary treatments.Pigs fed T3 (50% CPMCM) and T4 (60% CPMCM) recorded the highest (p ˂ 0.05) value of IgA, IgG and IgM followed by T2 (40% CPMCM) and T1 (0% CPMCM) (Table 5).This suggests that the presence of phytochemicals in CPMCM especially flavonoids may pose improve immune functions in pigs.According to Hashem et al. (2013); Alagbe (2024), flavonoids has been found to have antioxidant, anti-inflammatory and immunomodulation activities.Activities of these phytochemicals in CPMCM will further maintain a healthy gut in pigs.The result recorded in this study, is in agreement with the findings of Tripathi et al. (2008) who used FarmazymeR supplementation on processed cassava meal to feed growing pigs.

Conclusions
Livestock production and sustainability lies in the ability to produce healthy and least cost ration using available raw materials to meet up with animals nutritional requirements.It was concluded that cassava peel and Maize cob can be explored in the production of feed for swine because it contains several essential nutrients which can positively influence the performance of pigs.Replacing maize with CPMCM had no deleterious effect on the health status of animals.

Table 1 .
Gross composition of the experimental diets (% DM).

Table 2 .
Phytochemical composition of maize cob and cassava peel meal.