THE EFFECT OF BIOMODIFICATION WITH Trichoderma harzianum ON THE CHEMICAL COMPOSITION AND IN VITRO GAS FERMENTATION CHARACTERISTICS OF MELON SEED HUSK WITH OR WITHOUT SUPPLEMENTATION WITH WHEAT BRAN

ABSTRACT

The increasing cost and scarcity of conventional livestock feed ingredients in developing countries have intensified the search for alternative feed resources capable of supporting sustainable animal production. Agricultural by-products such as melon seed husk possess considerable potential as low-cost feed resources for ruminants; however, their utilization is constrained by high fibre content, low protein availability, and poor digestibility. This study evaluated the effect of biomodification with Trichoderma harzianum on the chemical composition and in vitro gas fermentation characteristics of melon seed husk supplemented with varying levels of wheat bran. Experimental treatments consisted of melon seed husk and wheat bran combinations at different inclusion levels (0%, 25%, 50%, 75%, and 100%) inoculated with Trichoderma harzianum and incubated for twenty-one days. The treated substrates were subsequently analyzed for proximate composition, fibre fractions, and fermentation characteristics using the in vitro gas production technique. Results revealed that fungal treatment and wheat bran supplementation improved crude protein content and reduced structural carbohydrate fractions such as neutral detergent fibre (NDF) and acid detergent fibre (ADF). However, reductions in gas production parameters, digestible dry matter, organic matter digestibility, and short-chain fatty acid production were observed in some treated samples. The findings indicate that biomodification with Trichoderma harzianum may improve certain nutritional properties of melon seed husk, although its effectiveness in enhancing fermentability and digestibility appears limited under the conditions of this study. The research contributes to ongoing efforts toward sustainable livestock nutrition, agricultural waste valorization, and eco-friendly feed biotechnology in Nigeria.

TABLE OF CONTENTS

• Title Page
• Certification
• Dedication
• Acknowledgements
• Abstract
• Table of Contents
• List of Tables
• List of Figures
• List of Plates

CHAPTER ONE: INTRODUCTION

1.1 Background to the Study
1.2 Statement of the Problem
1.3 Aim and Objectives of the Study
1.4 Research Questions
1.5 Research Hypotheses
1.6 Significance of the Study
1.7 Scope of the Study
1.8 Limitation of the Study
1.9 Definition of Terms

CHAPTER TWO: LITERATURE REVIEW

2.1 Conceptual Review
2.2 Agricultural Waste Utilization in Livestock Nutrition
2.3 Melon Seed Husk as a Feed Resource
2.4 Biological Treatment of Agro-Industrial Wastes
2.5 Trichoderma harzianum and Feed Biomodification
2.6 In Vitro Gas Production Technique
2.7 Factors Affecting Gas Fermentation Characteristics
2.8 Wheat Bran Supplementation in Ruminant Feeding
2.9 Empirical Review
2.10 Gap in Literature

CHAPTER THREE: MATERIALS AND METHODS

3.1 Experimental Site
3.2 Collection and Preparation of Samples
3.3 Experimental Treatments
3.4 Source and Maintenance of Fungal Culture
3.5 Inoculation and Fermentation Procedures
3.6 Chemical Analysis
3.7 Determination of Fibre Fractions
3.8 In Vitro Gas Fermentation Study
3.9 Statistical Analysis

CHAPTER FOUR: RESULTS AND DISCUSSION

4.1 Chemical Composition of Treated Samples
4.2 Fibre Fraction Analysis
4.3 In Vitro Gas Production Characteristics
4.4 Methane Production and Digestibility Parameters
4.5 Discussion of Findings

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS

5.1 Summary
5.2 Conclusion
5.3 Recommendations
5.4 Suggestions for Further Research

References

Appendices

CHAPTER ONE

INTRODUCTION

1.1 Background to the Study

Livestock production plays a critical role in food security, income generation, and rural development in many developing countries, particularly in sub-Saharan Africa. In Nigeria, the livestock sector contributes significantly to national agricultural output and serves as an important source of animal protein for the growing human population. However, one of the major constraints to efficient livestock production is the inadequate supply of quality feed resources throughout the year. Seasonal fluctuations in forage availability, rising costs of conventional feed ingredients, and increasing competition between humans and animals for cereal grains have intensified the need for alternative and sustainable feed resources.

The rapid increase in human population and urbanization has further placed pressure on existing agricultural resources, leading to high feed costs and reduced profitability in animal production systems. Consequently, attention has shifted toward the utilization of non-conventional feed resources, particularly agricultural residues and agro-industrial by-products that are not directly consumed by humans. These materials are often abundant, inexpensive, and environmentally sustainable when properly processed and utilized in animal nutrition (Makkar, 2000).

Melon seed husk is one of the agro-industrial residues generated during the processing of melon seeds for human consumption. Although the husk is produced in substantial quantities in many parts of Nigeria, it is often discarded as waste or burnt indiscriminately, contributing to environmental pollution. Despite its availability, the use of melon seed husk in livestock feeding is limited due to its low crude protein content, high lignocellulosic fibre composition, and poor digestibility.

Ruminant animals possess a unique digestive system that enables them to utilize fibrous materials through microbial fermentation in the rumen. However, the efficient utilization of agricultural residues is often constrained by the presence of structural carbohydrates such as cellulose, hemicellulose, and lignin, which reduce nutrient availability and feed digestibility. Improving the nutritional quality of such residues has therefore become a major focus in animal nutrition research.

Several processing methods, including physical, chemical, and biological treatments, have been investigated for improving the feeding value of low-quality agricultural by-products. Among these methods, biological treatment or biomodification has gained increasing attention because it is environmentally friendly, cost-effective, and sustainable. Biological treatment involves the use of microorganisms, particularly fungi, to degrade fibre components and improve nutrient availability in agricultural wastes.

Trichoderma harzianum is a filamentous fungus widely recognized for its cellulolytic and ligninolytic capabilities. The fungus has been extensively studied for agricultural and industrial applications, including biodegradation, biological control, enzyme production, and feed improvement. Through the secretion of extracellular enzymes such as cellulases and hemicellulases, Trichoderma harzianum can partially degrade complex plant cell wall components, thereby enhancing nutrient accessibility and potentially improving feed utilization.

The supplementation of agricultural residues with nutrient-rich feed ingredients such as wheat bran may further enhance microbial growth and fermentation efficiency during biomodification. Wheat bran serves as an energy and nutrient source capable of supporting fungal metabolism and improving the fermentation process. Combining melon seed husk with wheat bran may therefore improve the nutritional composition and fermentability of the treated substrate.

Evaluating the nutritional quality of treated feed materials requires reliable analytical techniques capable of estimating digestibility and fermentation characteristics. The in vitro gas production technique has become a widely accepted laboratory method for assessing ruminal fermentation kinetics and feed digestibility. The technique measures gas production resulting from microbial fermentation of feed substrates under controlled laboratory conditions and provides valuable information on feed utilization, digestibility, and energy availability (Getachew et al., 2004).

In vitro gas production studies also enable the estimation of parameters such as digestible dry matter, organic matter digestibility, methane production, and short-chain fatty acid synthesis, which are important indicators of feed quality and rumen efficiency. Consequently, the application of in vitro gas fermentation techniques provides an effective approach for evaluating the impact of biomodification on agricultural residues intended for ruminant feeding.

Against this background, this study investigates the effect of biomodification with Trichoderma harzianum on the chemical composition and in vitro gas fermentation characteristics of melon seed husk with or without supplementation with wheat bran. The research aims to contribute to sustainable livestock nutrition through improved utilization of agro-industrial wastes in Nigeria.

1.2 Statement of the Problem

The livestock industry in Nigeria faces persistent challenges associated with the scarcity and high cost of quality feed resources. Conventional feed ingredients such as maize and soybean meal are increasingly expensive due to competition with human consumption and industrial use. This situation has compelled livestock producers to explore alternative feed resources capable of reducing feed costs without compromising animal productivity.

Agricultural by-products such as melon seed husk are generated in large quantities but remain underutilized because of their low nutritional value, poor digestibility, and high fibre content. Improper disposal of these residues also contributes to environmental pollution and waste management problems.

Although biological treatment of agricultural wastes has shown potential in improving feed quality, limited information exists regarding the effectiveness of Trichoderma harzianum in enhancing the nutritional composition and fermentability of melon seed husk, particularly when supplemented with wheat bran. Furthermore, the impact of fungal biomodification on in vitro gas production parameters and ruminal fermentation characteristics remains insufficiently explored.

This study therefore seeks to evaluate the effect of biomodification with Trichoderma harzianum on the chemical composition and in vitro gas fermentation characteristics of melon seed husk with or without supplementation with wheat bran.

1.3 Aim and Objectives of the Study

The main aim of this study is to evaluate the effect of biomodification with Trichoderma harzianum on the chemical composition and in vitro gas fermentation characteristics of melon seed husk supplemented with wheat bran.

The specific objectives are to:

1. determine the effect of Trichoderma harzianum treatment on the proximate composition of melon seed husk;
2. evaluate the effect of fungal treatment on fibre fractions including neutral detergent fibre (NDF), acid detergent fibre (ADF), and hemicellulose;
3. assess the influence of wheat bran supplementation on the nutritional quality of treated melon seed husk;
4. investigate the in vitro gas production characteristics of treated and untreated samples;
5. determine digestibility indices such as digestible dry matter (DMD), organic matter digestibility (OMD), methane production, and short-chain fatty acid (SCFA) production;
6. identify the most suitable treatment combination for improving the feeding value of melon seed husk.

1.4 Research Questions

The study seeks to answer the following research questions:

1. Does biomodification with Trichoderma harzianum improve the chemical composition of melon seed husk?
2. What effect does wheat bran supplementation have on the nutritional quality of treated substrates?
3. How does fungal treatment influence fibre degradation in melon seed husk?
4. What are the effects of biomodification on in vitro gas production and fermentation characteristics?
5. Which treatment combination produces the best nutritional and fermentation outcomes?

1.5 Research Hypotheses

Null Hypothesis (H?)

Biomodification with Trichoderma harzianum has no significant effect on the chemical composition and in vitro gas fermentation characteristics of melon seed husk with or without wheat bran supplementation.

Alternative Hypothesis (H?)

Biomodification with Trichoderma harzianum significantly affects the chemical composition and in vitro gas fermentation characteristics of melon seed husk with or without wheat bran supplementation.

1.6 Significance of the Study

This study is significant because it contributes to ongoing efforts toward sustainable livestock feeding and efficient agricultural waste management. The findings may provide valuable information on the utilization of melon seed husk as an alternative feed resource for ruminant animals.

The study also promotes environmentally friendly technologies through the application of fungal biomodification for improving low-quality agricultural residues. This aligns with global initiatives aimed at reducing environmental pollution and promoting circular agricultural systems.

Furthermore, the research may benefit livestock farmers, feed manufacturers, animal nutritionists, agricultural researchers, and policymakers by providing practical insights into low-cost feed improvement strategies capable of enhancing animal productivity and reducing feed costs.

The use of in vitro gas production techniques in this study also contributes to scientific understanding of ruminal fermentation dynamics and feed evaluation methods in ruminant nutrition research.

1.7 Scope of the Study

This study focuses on the biomodification of melon seed husk using Trichoderma harzianum with or without supplementation with wheat bran. The research covers proximate analysis, fibre fraction determination, and in vitro gas fermentation characteristics of treated and untreated samples.

The study is limited to laboratory-based analysis and controlled fermentation procedures. Field feeding trials and animal performance evaluations are outside the scope of this research.

1.8 Limitation of the Study

The study may be limited by financial constraints, availability of laboratory facilities, and access to specialized analytical equipment. Variations in microbial activity, environmental conditions, and substrate composition may also influence fermentation outcomes.

Despite these limitations, standard laboratory procedures and appropriate experimental controls will be employed to ensure reliability and validity of the findings.

1.9 Definition of Terms

Biomodification

The biological treatment of materials using microorganisms to improve their nutritional, physical, or chemical properties.

Trichoderma harzianum

A beneficial fungus known for its cellulolytic activity and ability to degrade plant fibre components.

Melon Seed Husk

The outer covering or residue obtained after processing melon seeds for human consumption.

Wheat Bran

The outer layer of wheat grain removed during milling and commonly used as livestock feed.

In Vitro Gas Production

A laboratory technique used to estimate feed fermentation and digestibility through gas measurement during microbial incubation.

Neutral Detergent Fibre (NDF)

A measure of plant cell wall components including cellulose, hemicellulose, and lignin.

Acid Detergent Fibre (ADF)

A measure of cellulose and lignin fractions in feed materials.

Short-Chain Fatty Acids (SCFA)

Organic acids produced during microbial fermentation in the rumen and used as energy sources by ruminants.

Digestibility

The extent to which nutrients in feed are broken down and absorbed by animals.

REFERENCES

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