INTRODUCTION
Physiological stress and physical injury are the primary contributing factors of fish disease and mortality in aquaculture. Stress is defined as physical or chemical factors that cause bodily reactions that may contribute to disease and death. He further observed that Fishes tend to produce mucus under stressful conditions; any stress causes chemical changes in mucus which decrease its effectiveness as a chemical barrier against invading organisms. Stress upsets the normal electrolyte (sodium, potasssium and chloride) balance (Rottmann, Francis-Floyd & Durborow,1992).
The way and manner live fish are transported is a very important aspect of fish culture. In most cases, fries (freshly hatched and baby fish) and fingerlings (few weeks old baby fish) must be transported from hatchery to pond for stocking; Brood fish (sexually mature fish selected for reproduction) are sometimes transported into the hatchery to spawn; therefore a fish farmer must be very familiar with the principles, techniques and practices of fish transportation so as to minimize fish death resulting from transportation because the ultimate aim of transportation is to provide healthy live fish at its destination. The author however observed that tolerance of fish to transport is related to their ability to resist or adapt to stressful conditions as described by Bolorunduro (1995).
Stress in fish has been widely studied and it was observed that cortisol and glucose are two of the most common stress indicators. They further opined that in spite of the extended use of these indicators and their acceptance, some inconsistencies have been reported in the results of several experimental studies, much of them associated to undefined and uncontrolled variables which may alter the response in secretion of cortisol and glucose into the bloodstream . In addition, he reported that most of those factors are not considered as direct stressors but have an effect on the intensity of the response which may be related to metabolic changes in the organisms as an adaptation or acclimation mechanism (Marcel, Luis, & Rogelio, 2009).
The African catfish (Clarias gariepinus) are weakened by stress conditions including: increased fish density and poor water quality (i.e., low dissolved oxygen, undesirable temperature or pH, increased levels of carbon dioxide, ammonia, nitrite, hydrogen sulfide, organic matter in the water); injury during handling (i.e., capture, sorting, shipping); inadequate nutrition; and poor sanitation. The authors further opined that these conditions can result in decreased resistance by the fish, resulting in the spread of disease and parasite infestation (Crosby, Hill, Martinez, Watson & Yanong,2006).
Various chemical additives have been used to transport live fish with few exceptions, there is little evidence to support claims of any real benefit. He opined that anesthetics can produce the same stress response as handling although anesthetics are beneficial for calming excitable fish that might injure themselves in transit. In addition, he reported that the only additives recommended for food fish transport are food grade salts and Sodium chloride (table salt) is the most common; Several other biologically important salts are used also. Furthermore, the author reported that fish and other vertebrates have a unique and common characteristic; the salt content of their blood is almost identical to the vertebrate blood which has a salinity of approximately 9 g/l (a 0.9% salt solution) and a pH of 7.4. Furthermore, the author reported that approximately 77% of the salt in blood is sodium and chloride, the remainder is made up primarily of bicarbonate, potassium and calcium. sodium and potassium salts which are critical for the normal functioning of the heart, nerve and muscle (William, 2005).
An 8 g/l (0.8%) salt solution made with table salt (sodium chloride) would match the sodium content of blood(William, 2005). Fish blood is brought into close contact (1- or 2-cell separation) with the environment as it flows through the small blood vessels (capillaries) of the gills and skin surface, salts diffuse from areas of high concentration (blood) to areas of low concentration (fresh water); Therefore, salts (primarily sodium and chloride) are slowly but continuously lost (osmotic leakage) to the environment. The author further added that the gills and skin are coated with a thin layer of mucus which helps reduce the loss of salts to the surrounding fresh water . However, he stated that lost salts are replaced by reabsorbing them from the water or during food digestion whereby body energy is used to replace salts. He stated that netting or handling removes some of the protective mucous coating from fish, transferring and transporting fish to and from ponds and live-haul tanks requires handling and travel which cause stress. He added that transport stress and loss of mucus increases salt leakage from the blood; placing higher energy demands on fish that are already weakened (William, 2005).
Excessive salt loss can cause heart failure as well as nerve and muscle spasms (tetany); the addition of sodium chloride limits or prevents (depending on concentration) the loss of salt during transport. The author reported that if fish are placed in a 9 g/l salt solution, no salt loss will occur because the concentrations of the solution and blood match; the addition of salts to transport water stops or minimizes salt loss by reducing or eliminating concentration differences between fish blood and environmental water which further reduces energy demands and diffusion leakage while providing a large supply of environmental salts for reabsorption and replacement of lost blood salts. In addition, he stated that in a bid to handle stress, salt concentrations 10 g/l (1.0%) or greater could be harmful to fish during live transport; fish blood is a 9 g/l salt solution, higher concentrations in hauling water cause the loss of water from blood (osmosis) while salts from the transport solution diffuse into the blood, this could cause fish to become dehydrated. Moreover, he added that a 10 g/l salt solution is approximately 10% higher than blood (9 g/l) and could create a 10% dehydration during transport; It is generally accepted that a 10% dehydration can be lethal to most vertebrates; therefore it would be advisable to use transport solutions containing less than 9 g/l salt. Furthermore, he stated that an 8g/l sodium chloride solution matches blood sodium content and is slightly lower than 9 g/l; preventing dehydration and shock by keeping kidneys active and salt loss low. He reported that traditionally, 0.5 to 2 g/l (0.05 to 0.2%) sodium chloride solutions have been used to reduce stress during fish transport. However, the author concluded that an 8 g/l (0.8%) sodium chloride solution more closely duplicates fish blood (William, 2005).
Water balance in the fish (osmoregulation) is disrupted due to changes in the metabolism of minerals. Under these circumstances, C. gariepinus absorb excessive amounts of water from the environment (over-hydrate); This disruption increases energy requirements for osmoregulation. Fish are able to adapt to stress for a period of time; they may look and act normal. However, energy reserves are eventually depleted and hormone imbalance occurs, suppressing their immune system and increasing their susceptibility to infectious diseases (Rottmann et al., 1992).
Palm oil is also loaded with the following phytonutrients namely; Carotenoids (alpha-, beta-, and gamma-carotenes), sterols, vitamin E (tocopherols and tocotrienols) and water-soluble powerful antioxidants, phenolic acids and flavonids; the health benefits of palm oil include reduced risk of a variety of disease processes(Edem, 2002). Additives such as palm oil and non-iodized salts are seen as one of the efficient means of ameliorating stress by maintaining its physical appearance in catfish (Falaye, Omoike Folorunso & Bello, 2012).
The effect of palm oil on fish requires further research, but the use of this saturated vegetable oil may reduce oxidative stress in fish, thereby reducing pathological conditions associated with this physiological stress(Oguntibeju, Esterhuyse & Truter,2009).
TABLE OF CONTENT
TITLE PAGE ……......i
CERTIFICATION.... ii
DECLARATION.......iii
DEDICATION……..iv
ACKNOWLEDGEMENT... v
TABLE OF CONTENT…....vi
LIST OF TABLES... x
LIST OF PLATES... xi
ABSTRACT…….....xi
CHAPTER ONE
1.0 INTRODUCTION .........................1
1.1 JUSTIFICATION ......................4
1.2 AIM OF STUDY .............5
1.3 OBJECTIVES OF THE STUDY ............5
1.4 NULL HYPOTHESES (Ho) ................5
1.5 LITERATURE REVIEW ...............6
1.5.1 STRESS IN FISH.................6
1.5.2 ACUTE AND CHRONIC STRESS IN CATFISH.....9
1.6 MUCUS PRODUCTION IN Clarias gariepinus...........9
1.6.1 COMPOSITION OF FISH MUCUS........................10
1.6.1.1 Mucins .............10
1.6.1.2 Innate Immune Components .........10
1.6.1.3 Enzymes ..........11
1.6.2 SITES OF MUCUS PRODUCTION IN Clarias gariepinus..............12
1.6.3 FUNCTIONS OF MUCUS IN Clarias gariepinus.......12
1.6.4 STRESS AND ITS EFFECTS IN Clarias gariepinus....13
1.7 BRIEF HISTORY OF PALM OIL (Elaeis guineensis)...15
1.7.1 Biological And Chemical Composition Of Palm Oil Elaeis guineensis ..........15
1.7.1.1 Fatty Acids .......16
1.7.1.2 CAROTENES...16
1.7.1.3 Anti-Oxidants ....16
CHAPTER TWO
2.0 MATERIALS AND METHODS ........17
2.1 MORPHOLOGY, DISTRIBUTION AND CLASSIFICATION OF Clarias gariepius..............17
2.1.1 CLASSIFICATION OF Clarias gariepius .....................18
2.2 THE PALM OIL USED (Elaeis guineensis)....................20
2.3 PHYTOCHEMICAL SCREENING OF PALM OIL ....20
2.3.1 Alkaloids..............20
2.3.2 Cardiac Glycosides................20
2.3.3 Steroids................20
2.3.4 Flavonoids............20
2.3.5 Tannins..................21
2.3.6 Anthraquinones ....................21
2.3.7 Carbohydrates ......21
2.3.8 Saponin ...............21
2.3.9 Terpenoids ...........22
2.4 SOURCE OF THE EXPERIMENTAL FISH..................22
2.4.1 Source Of Water And Loading The Experimental Fish......22
2.4.2 Experimental Design..................22
2.4.3 Fish Acclimatization ............................22
2.5 EXPERIMENTAL PROCEDURES ...23
2.5.1 The Various Concentration of E. guineensis used on Different Age Groups of C. gariepinus ............25
2.5.2 Determination of Treatment’s Concentration .............27
2.5.3 Collection Of Water For Physico-Chemical Analysis ....... 29
2.5.3.1 Water Temperature ..............29
2.5.3.2 Dissolved Oxygen (DO) .....................29
2.5.3.3 Free Carbon Dioxide (CO2) ...............30
2.5.3.4 pH..........................30
2.5.3.5 Alkalinity ................31
2.6 BLEEDING THE EXPERIMENTAL FISH .......................31
2.7 BIOCHEMICAL PROCEDURES FOR SERA SAMPLES .........31
2.7.1 Direct Bilirubin (DB) .31
2.7.2 Total Bilirubin (TB)....32
2.7.3 Protocol for Albumin (ALB) ..................32
2.7.4 Protocol for Alanine aminotransferase (ALT) ..........33
2.7.5 Protocol for Aspartate aminotransferase (AST) ........33
2.7.6 Protocol for Alkaline phosphatase (ALP) ............34
2.8 STATISTICAL ANALYSIS .........35
CHAPTER THREE
3.0 RESULTS........... 36
3.1 PHYTOCHEMICAL SCREENING OF PALM OIL (Elaeis guineensis) ......38
3.2 PHYSICO-CHEMICAL ANALYSIS OF WATER TO DETERMINE STRESS RESPONSES IN FINGERLINGS OF Clarias gariepinus INITIAL AND FINAL RESULTS OF AGITATION...39
3.3 PHYSICO-CHEMICAL ANALYSIS OF WATER TO DETERMINE STRESS RESPONSES IN JUVENILES OF Clarias gariepinus INITIAL AND FINAL RESULTS OF AGITATION..........40
3.4 PHYSICO-CHEMICAL ANALYSIS OF WATER TO DETERMINE STRESS RESPONSES IN ADULTS OF Clarias gariepinus INITIAL AND FINAL RESULTS OF AGITATION...............41
3.5 ENZYME PROFILE/ PROTEIN ANALYSIS OF SERA SAMPLES OF FINGERLINGS OF Clarias gariepinus ..........42
3.6 ENZYME PROFILE/ PROTEIN ANALYSIS OF SERA SAMPLES OF JUVENILES OF Clarias gariepinus .....43
3.7 ENZYME PROFILE/ PROTEIN ANALYSIS OF SERA SAMPLES OF ADULTS OF Clarias gariepinus ....44
CHAPTER FOUR
4.0 DISCUSSION, CONCLUSION AND RECOMMENDATION .............45
4.1 DISCUSSION .............45
4.2 CONCLUSION...........52
4.3 RECOMMENDATION .... 53
REFERENCES.......................54