PhD Thesis MJProl .pdf - digital-csic Digital CSIC - Consejo Superior ...

More documents

Recommendations

Info

18 Immobilization of Phaeobacter 27-4 in biofilters parameters include phagocytes, the complement system, various lectins, lytic enzymes, antibacterial peptides and proteinase inhibitors (Magnadottir et al., 2005). A variety of substances could, at least theoretically, activate these innate parameters. These substances or immunostimulants have recently been defined as “a naturally occurring compound that modulates the immune system by increasing the host’s resistance against diseases that in most circumstances are caused by pathogens” (Bricknell and Dalmo, 2005). In general, these are compounds of bacterial, fungal or plant origin, particularly composed of polysaccharides, which activate the pattern recognition receptors/proteins of the immune system resulting in a varied immune response. Previous studies have demonstrated that administration of immunostimulants to fish is beneficial, providing improved protection against bacterial and, to a lesser extent, viral infections (Bricknell and Dalmo, 2005; Vadstein, 1997). Thus, the immunomodulation of larval fish has been proposed as a potential method for improving larval survival by increasing the innate responses until its adaptive immune response is sufficiently developed to generate an effective response to the pathogen. Lipopolysaccharides (LPS) are one of the immunostimulants widely used in experimental fish larval aquaculture, as they can trigger various immune components. Sea bream (Sparus aurata) larvae when treated with LPS exhibited significantly high anti-protease activity, lysozyme activity and total globulin level, and also conferred protection against Photobacterium damsela (Hanif et al., 2005). Similarly, Magnadottir et al. (2006) reported enhanced survival by immunising Atlantic cod (Gadus morhua) with LPS. The range of potential immunostimulants for larval fish is quite limited and a short review can be found in Table 1.2. Although these studies have demonstrated some beneficial effects of immunostimulants in terms of survival and growth, the relative importance of the immune mechanisms involved remains unknown. It is also important to consider the specificity of immunostimulants, since the stimulation may be too intense, which may become detrimental or even lethal to the host. Moreover, the knowledge of the functions of different immunostimulators may be used to stimulate, more specifically, those parts of the immune system that may be more relevant in certain situations (Vadstein, 1997). The recent introduction of genomic and proteomic tools might be of special interest in this context.
New strategies for the control of bacterial infections in marine fish larval rearing 19 Table 1.2. The immunostimulants used in fish larval aquaculture. Immunostimulant Species Effect Reference Alginate Turbot (Psetta maxima) Cod milt proteins β-1,3/β-1,6 glucans β-glucans and mannanoligosaccharides Lipopolysaccharide Atlantic cod (Gadus morhua) Atlantic cod (Gadus morhua) Common dentex (Dentex dentex) Chilean flounder (Paralichthys adspersus) Atlantic cod (Gadus morhua) Sea bream (Sparus aurata) Survival improvement and growth increase Conceicão et al. (2004) Survival improvement Pedersen et al. (2004) Survival improvement and growth increase Survival improvement and growth increase Survival improvement and growth increase 1.3. Strategies based on the food chain Survival improvement Skjermo et al. (2006) Efthimiou (1996) Piaget et al. (2007) Magnadottir et al. (2006) Survival improvement Hanif et al. (2005) Large scale use of probiotics in the rearing of marine fish larvae involves cultivation of bacteria in artificial medium, preparation of a stable form of these bacteria and development of a process for the transfer of probiotics to the larval gut either by direct addition to seawater in the rearing tanks or by bioencapsulation in live feed. The approach of addition of bacteria to the seawater is simpler but implicates that the added bacteria remain in the seawater column for some time to be filtered by rotifers or Artemia and thereby to be introduced in the larval gut. A far more efficient approach is the bioencapsulation of bacteria in live feed. This is the only possible route in the case of allochthonous bacteria of tellurian origin tested in larviculture, such as lactic acid bacteria and Bacillus strains (Gatesoupe, 1994). These bacteria are not normally encountered in marine systems, but when introduced in larvae may have positive effects for the larvae by excreting antimicrobial compounds or by other ways limiting the growth of harmful bacteria. Bioencapsulation of bacteria is a relatively predictable process in the case of rotifers but more variable in the case of Artemia metanauplii, as the size of bacteria may prove decisive for the efficiency of the process (Makridis et al., 2000). Artemia metanauplii have a filtering device which enables them to filter large bacterial cells or
Page 1: INSTITUTO DE ACUICULTURA CONSEJO SU
Page 5: The work presented in this Ph.D. Th
Page 8 and 9: viii López Cabo do grupo de tecono
Page 11 and 12: INDEX 1. INTRODUCTION: NEW STRATEGI
Page 13 and 14: Index 5.3.2. Effect of pathogens co
Page 15: Index 7.4. REFERENCES 172 8. ANNEXE
Page 18 and 19: xviii Abstract The third step consi
Page 21: 1 INTRODUCTION This chapter has bee
Page 24 and 25: 4 Immobilization of Phaeobacter 27-
Page 30 and 31: 10 Immobilization of Phaeobacter 27
Page 57 and 58: 2. BACKGROUND Phaeobacter 27-4 as p
Page 59 and 60: Phaeobacter 27-4 as probiotic again
Page 65: Phaeobacter 27-4 as probiotic again
Page 69 and 70: 3. OBJECTIVES Objectives The main o
Page 71: Objectives 3.1.1. Growth and biofil
Page 75 and 76: 4. CHAPTER I Chapter I. Real-time P
Page 77 and 78: Chapter I. Real-time PCR detection
Page 89 and 90:
Chapter I. Real-time PCR detection
Page 91 and 92:
Page 93 and 94:
Page 95 and 96:
Page 97:
Chapter II. Colonization and reside
Page 100 and 101:
80 Immobilization of Phaeobacter 27
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 127:
6 CHAPTER III
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177:
Page 178 and 179:
Page 180 and 181:
Page 183 and 184:
Final Discussion, Conclusions & Fut
Page 185 and 186:
Page 187 and 188:
Page 189 and 190:
Page 191 and 192:
Page 193 and 194:
Page 195:
Page 199 and 200:
8. RESUMO EN GALEGO (ABSTRACT IN GA
Page 201 and 202:
Anexo competencia por nutrientes li
Page 203 and 204:
Anexo Phaeobacter 27-4 é inocua pa
Page 205 and 206:
Anexo para os patóxenos da familia
Page 207 and 208:
Anexo probióticos. As colonias de
Page 209 and 210:
Anexo 8.5. Capítulo III: Aplicaci
Page 211 and 212:
Anexo Austin, B., Brunt, J.W., 2009
Page 213 and 214:
Anexo Huys, L., Dhert, P., Robles,
Page 215:
Anexo Skjermo, J., Vadstein, O., 19
show all

PhD Thesis MJProl .pdf - digital-csic Digital CSIC - Consejo Superior ...

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?