chapter 3 - RiuNet

More documents

Recommendations

Info

GENERAL DISCUSSION more studies on multifactorial sperm biomarkers. For example, Lahnsteiner el al. (1998) reported that in rainbow trout motile spermatozoa, seminal plasma pH and sperm metabolism were able to explain a high percentage of variance in fertilization rates. In fact, some sperm traits in that trial were linked, and subsequently high quality semen was characterised by high sperm motility (≥75%), medium sperm swimming velocities (100–120 μm/s) and optimal seminal fluid protonic composition (pH of 8.0–8.2). In this respect, it suggests that in-depth knowledge of as many sperm traits as possible allows us to establish the relationships between them, making it possible to assess sperm quality though a small set of species-specific biomarkers able to predict both fertilization and hatching rates. Following on from this basic idea, CASA systems are able to provide us with many spermatozoa motion parameters, and each one can be correlated with the spermatozoa ability to fertilize the oocyte. In fact, positive correlations between fertilization and hatching rates and many CASA parameters (8 out of 13) were found in pufferfish (see Chapter 5). The subsequent questions are: which should we choose? Which are the most important? Really, the answer is to choose those which show the highest correlations, and checking a so far not very extensive bibliography on this topic in fish can help us make this choice. However, another approach could be to study sperm subpopulations. This kind of study uses data mining techniques such as cluster analysis, grouping the spermatozoa in subpopulations that have a biological meaning (Martinez-Pastor et al., 2011). In this respect, although there are scarce reports in fish, other recent trials have reported the coexistence of several subpopulations in different species. For example, 3 sperm subpopulations have been described in European eel sperm, and they have been used to evaluate different treatments for the induction of maturation in this species (Gallego et al., submitted). In this case, subpopulations were made by taking some CASA parameters, not often used for assessing directly the sperm quality, as a basis (LIN, WOB, ALH and DNC). For this reason, it is important to note that all the sperm parameters analyzed by CASA systems must be taken into account in order to generate powerful and useful information to detect new sperm quality biomarkers in fish species. 129
GENERAL DISCUSSION Sperm motion parameters become a helpful tool not only for aquaculture purposes, but also regarding other diverse issues. For example, it has been reported that environmental pollution from cadmium or zinc, can affect sperm motility parameters and thus, reproduction success (Kime et al., 1996). In this respect, it would be possible to detect toxic discharges in aquatic environments simply by assessing some fish sperm motion parameters. Another powerful application is that of ethological matters: some fish species show complex social relationships between males, resulting in a different mating tactics, and it is astonishing to observe how sperm motion is complexly defined by the status of the male (Fitzpatrick et al., 2007; Gallego et al., unpublished results). To summarize, the study of the sperm motion parameters assessed by a CASA system during these IVF trials has made some of them useful fish sperm quality biomarkers. Which, how and where to apply them it depends directly on the species and the aim of the research, but sperm biomarkers have proven themselves to be useful tools which can be applied in a wide range of fields such as aquaculture, and for scientific or ecological purposes. 3. New data about the sperm activation process in marine fish Spermatozoa from external fertilizers are usually released in a hostile external medium, where they have to cope with extremely harmful conditions on their way to reach and fertilize the oocyte (Cosson et al., 2004). In this respect, the features of the aquatic environment will define, in addition to the sperm activation, both the swimming time period and the motion patterns of the spermatozoa. In this thesis we have shown that both the osmolality and the availability of certain ions (Ca 2+ and K + ) in the activation media are able to affect the normal motion patterns of spermatozoa. Understanding how these factors affect sperm motility could be key in improving spermatozoa performance for aquaculture matters. Regarding osmolality, partly diluted sea water has been used in some marine species to induce good motility activation without exposing sperm to extreme osmotic conditions, increasing thus the 130
Page 2 and 3:
SPERM PHYSIOLOGY AND QUALITY IN TWO
Page 4 and 5:
ACKNOWLEDGEMENTS Muchos años han p
Page 6 and 7:
aunque tiene una alcachofa en la ca
Page 8 and 9:
TABLE OF CONTENTS SUMMARY 1 RESUMEN
Page 10 and 11:
SUMMARY SUMMARY The conservation st
Page 12 and 13:
RESUMEN RESUMEN Las especies objeto
Page 14 and 15:
RESUM RESUM Les espècies objecte d
Page 16:
GENERAL INTRODUCTION 7
Page 19 and 20:
GENERAL INTRODUCTION who postulated
Page 21 and 22:
GENERAL INTRODUCTION 2. Sperm physi
Page 23 and 24:
GENERAL INTRODUCTION Finally, the a
Page 25 and 26:
GENERAL INTRODUCTION 3. Sperm quali
Page 27 and 28:
GENERAL INTRODUCTION in fish (Kime
Page 29 and 30:
GENERAL INTRODUCTION However, for s
Page 31 and 32:
GENERAL INTRODUCTION future applica
Page 33 and 34:
GENERAL INTRODUCTION With regards t
Page 36:
OBJECTIVES The chapters presented b
Page 40 and 41:
STANDARDIZATION OF SPERM MOTILITY E
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56:
CHAPTER 2 Study of the effects of t
Page 59 and 60:
CHAPTER 2 reducing the pressure on
Page 61 and 62:
CHAPTER 2 ongoing task in order to
Page 63 and 64:
CHAPTER 2 To measure sperm density,
Page 65 and 66:
CHAPTER 2 Spermiating males (%) 100
Page 67 and 68:
CHAPTER 2 100 80 60 I II III IV A 4
Page 69 and 70:
CHAPTER 2 3.2 Hormonal treatments P
Page 71 and 72:
CHAPTER 2 With regard to the sperm
Page 73 and 74:
CHAPTER 2 Relative volume (%) 80 I
Page 75 and 76:
CHAPTER 2 In this respect, it is we
Page 77 and 78:
CHAPTER 2 treatment to that of the
Page 79 and 80:
CHAPTER 2 Our results demonstrate t
Page 82 and 83:
ROLE OF IONS IN THE SPERM ACTIVATIO
Page 84 and 85:
Page 86 and 87:
Page 88 and 89: ROLE OF IONS IN THE SPERM ACTIVATIO
Page 90 and 91: ROLE OF IONS IN THE SPERM ACTIVATIO
Page 92: CHAPTER 4 Study of pufferfish (Taki
Page 95 and 96: CHAPTER 4 2002) so Takifugu niphobl
Page 97 and 98: CHAPTER 4 carrying out sperm collec
Page 99 and 100: CHAPTER 4 Table 1. Activation media
Page 101 and 102: CHAPTER 4 TM (%) 100 A a a Und-PD a
Page 103 and 104: CHAPTER 4 TM (%) 80 60 40 20 0 A a
Page 105 and 106: CHAPTER 4 TM (%) 80 A ASW100 GLU 60
Page 107 and 108: CHAPTER 4 although the activation m
Page 109 and 110: CHAPTER 4 dilution ratio and an opt
Page 111 and 112: CHAPTER 4 2006). Several studies in
Page 113 and 114: CHAPTER 4 5. Conclusions Some concl
Page 116 and 117: RELATIONSHIP BETWEEN SPERM MOTILIY
Page 130: RELATIONSHIP BETWEEN SPERM MOTILIY
Page 134 and 135: GENERAL DISCUSSION 1. Improvements
Page 136 and 137: GENERAL DISCUSSION profiles induced
Page 140 and 141: GENERAL DISCUSSION sperm motility p
Page 142: CONCLUSIONS 133
Page 145 and 146: CONCLUSIONS vii. The coefficients o
Page 148 and 149: REFERENCES Aarestrup K, Økland F,
Page 150 and 151: REFERENCES Beirão J, Cabrita E, P
Page 152 and 153: REFERENCES Cabrita E, Robles V, Cu
Page 154 and 155: REFERENCES De Vos A, Van De Velde H
Page 156 and 157: REFERENCES Gallego V, Pérez L, Ast
Page 158 and 159: REFERENCES sperm competition and fe
Page 160 and 161: REFERENCES Liu QH, Li J, Xiao ZZ, D
Page 162 and 163: REFERENCES Mortimer ST. Effect of i
Page 164 and 165: REFERENCES Peñaranda DS, Marco-Jim
Page 166 and 167: REFERENCES Rurangwa E, Volckaert FA
Page 168 and 169: REFERENCES Tesch F. Telemetric obse
Page 170 and 171: REFERENCES Wong PYD, Lee WM, Tsang
show all

chapter 3 - RiuNet

Create successful ePaper yourself

Delete template?

Save as template?