Effect of Replacement of Soybean Meal with Cocoyam

EFFECT OF REPLACEMENT OF SOYBEAN MEAL WITH COCOYAM

LEAVES (Colocasia esculenta) MEAL ON THE GROWTH AND PLASMA

ENZYME PROFILE OF AFRICAN CATFISH (Clarias gariepinus).

AWOLU, TAIWO EZEKIEL

(B. Agric. Tech., (Honours) FUTMINNA)

FAT/13/5442

A THESIS IN THE DEPARTMENT OF FISHERIES AND AQUACULTURE TECHNOLOGY SUBMITTED TO THE SCHOOL OF POSTGRADUATE STUDIES

IN PARTIAL FULFILMENT OF THE REQUIREMENT FOR THE AWARD OF THE DEGREE OF MASTER OF AGRICULTURAL TECHONOLGY (M. TECH) IN FISHERIES AND AQUACULTURE TECHNOLOGY OF THE FEDERAL UNIVERSITY OF TECHNOLOGY AKURE, ONDO STATE, NIGERIA

ABSTRACT

The effects of replacing soybean meal with cocoyam leaf (Colocasia esculenta) meal on the growth and plasma enzymes profile of African catfish (Clarias gariepinus) juveniles were investigated in a feeding trial that lasted for 56days. C. esculenta leaf meal was used as a replacement for soyabean protein fraction in a 40% crude protein (CP) diet at 0% (CYL0) (control), 30% (CYL30), 40%

(CYL40), 60% (CYL60) and 80% (CYL80). One hundred and fifty C. gariepinus juveniles (mean weight 31.5 ± 0.94g) were randomly distributed into glass aquaria tanks at 10fish/tank in triplicate treatments of five and were fed twice daily at 8:00-9:00hrs and 16:00-17:00hrs. The mean weight gain, specific growth rate, protein efficiency ratio and feed efficiency ratio decreased with increasing levels of C. esculenta leaf meal in the diets and there were significant differences

(P<0.05) in the values of the parameters of fish fed the control diet (CYL0) and treated feed (CYL30

- CYL80). Haematological indices showed that packed cell volume (PCV), white blood cell

(WBC), differential count, Mean Corpuscular Haemoglobin Concentration (MCHC), Mean

Corpuscular Haemoglobin (MCH), and Mean Corpuscular Volume (MCV) were not significantly affected. The blood plasma enzyme profile revealed a difference (P<0.05) in the Lactic

Dehydrogenase (LDH) and, Glutamate Oxaloacetic Transaminase (GOT), Glutamate Pyruvate

Transaminase (GPT), Acid Phosphatase (APT), total protein and globulin. All fish fed diets with the cocoyam leaf meal had significantly higher total protein, globulin and glutamate pyruvate than the fish fed control diet, and the values of these parameters increased with increasing levels of the cocoyam leaves meal. The apparent digestibility coefficient (ADC) of nutrients ADCprotein,

ADClipid and ADCenergy indicated slight variations (P>0.05) as dietary treatment effects. The carcass and mineral compositions differed marginally across all treatments. In summary, cocoyam leaves meal can replace soybean meal in the diets of African catfish but other processing methods for cocoyam leaves can be explore to reduce the antinutrients in these leaves which inhibit growth.

CHAPTER ONE

1.0 INTRODUCTION

Fish is generally accepted as protein source in diets of average Nigerians (Agbabiaka, 2010).

Nutritionally, fish is about the cheapest and direct source of protein and micro nutrients for several millions of Africans (Bene and Heck, 2005). Over the past decades aquaculture has grown in leaps and bounds in response to an increasing demand for fish as a source of protein globally (Akinrotimi et al., 2007). This is because production from capture fisheries has reached its maximum potential possible, as the catch is dwindling with each passing day (Gabriel et al., 2007). According to FAO

(2006), fish supplies from capture fisheries will therefore, not be able to meet the growing global demand for aquatic food. Hence, there is the need for a viable alternative fish production system that can sufficiently meet this demand, and aquaculture fits exactly into this role.

Feed accounts for minimum of 60% of the total cost of fish production in Africa (Jamiu and Ayinla,

2003) and a major factor that determines the viability and profitability of fish farming enterprise.

Aquaculture development in sub-Sahara Africa including Nigeria has been reported to be insignificant compared to the rest of Europe and Asia (Changadeya et al., 2003) perhaps due to non availability of quality feed at economic prices. As aquaculture production becomes more and more intensive in Nigeria, fish feed will be a significant factor in increasing the productivity and profitability of aquaculture (Akinrotimi et al., 2007). Jamiu and Ayinla (2003) opined that feed management determines the viability of aquaculture as it accounts for at least 60 percent of the cost of fish production. The need to intensify the culture of the fish, so as to meet the ever increasing demand for fish has made it essential to develop suitable diets either in supplementary

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