- ข้อความ
- ประวัติศาสตร์
4. DiscussionPrevious investigation
4. Discussion
Previous investigations have showed that vitamin E requirements of
fish are affected by dietary lipid levels (Watanabe et al., 1977; Lovell
et al., 1984; Satoh et al., 1987; Roemet al., 1990; Shiau and Shiau, 2001).
Results of the present study shown that, based on weight gain, FI, FER
and survival, vitamin E requirement of Nile tilapia was not affected by
dietary lipid levels and supplementation of 50 mg of vitamin E/kg diet
(analyzed values of 112 mg/kg) was sufficient for tilapia fed purified
diets containing an equal mixture of corn oil and menhaden fish oil
ranging from 6 to 14%. This value is higher than those determined by
Roem et al. (1990) for O. aureus (10 and 25 mg/kg of diet at 3 and 6%
dietary lipid, respectively, or 3 to 4 mg vitamin E per percent of corn oil)
and Shiau and Shiau (2001) for hybrid tilapia (O. niloticus×O. aureus)
(42–44 mg/kg and 60–66 mg/kg in diets containing 5% and 12% lipid,
respectively). These values, however, are considerably lower than the
requirement values of 50 to 100 mg/kg for a diet containing 5% lipid
(pollock liver oil) and 500 mg/kg for a diet containing 10 to 15% lipid
reported for Nile tilapia (Satoh et al., 1987).Whether the differences in
the degree of fatty acid unsaturation between the lipid source used in
this study and that of Satoh et al. (1987) contributed to the differences
in the vitamin E requirements cannot be ascertained. However, it has
been reported that, in fish, high levels of dietary highly unsaturated
fatty acids induced higher vitamin E requirements (Cowey et al.,
1983; Roem et al., 1990). It should be noted that our diets were also
supplemented with the antioxidant, ethoxyquin, at 200 mg/kg diet.
Ethoxyquin, although it has no biological activity of vitamin E, can
partially spare vitamin E in the diet for growth and other physiological
functions (Lovell et al., 1984).
The non-significant effect of increasing dietary lipid levels from 6
to 14% on weight gain, feed intake and survival was expected because
our test diets were isonitrogenous and isocaloric and contained
essential nutrients at levels that meet or exceed the know requirements
for tilapia. A number of earlier studies have reported similar
weight gain and FER of channel catfish, Ictalurus punctatus (Gatlin and
Stickney, 1982; Twibell and Wilson, 2003; Yildirim-Aksoy et al.,
2007), blue tilapia (O. aureus) (Roem et al., 1990) and European sea
bass (Dicentrarchus labrex) (Peres and Oliva-Teles, 1999) fed diets
supplemented with increasing levels of fish oil. The non-significant
effect of dietary fish oil levels on feed intake has also been reported for
channel catfish by Twibell and Wilson (2003) and Yildirim-Aksoy
et al. (2007). However, significantly lower FER in fish fed diets
supplemented with 14% lipid, regardless of dietary levels of vitamin E,
may be due to excessive levels of dietary lipid. Lim and Webster
(2006) reported that tilapia do not tolerate as high a dietary lipid as do
salmonids. A dietary lipid level in excess of 12% depressed growth of
juvenile O. aureus×O. niloticus hybrids (Jauncey and Ross, 1982;
Jauncey, 2000). Thus, for good FER, lipid levels in diets of Nile tilapia
juveniles should not exceed 10%.
Increasing supplemental lipid levels to 14% significantly increased
whole body lipid and decreased moisture, as has been reported for
several fish species fed increasing levels of dietary lipid (Jauncey and
Ross, 1982; Viola et al., 1988; De Silva et al., 1991; Stowell and Gatlin,
1992; Chou and Shiau, 1996; Peres and Oliva-Teles, 1999; Jauncey,
2000; Yildirim-Aksoy et al., 2007). Other studies, however, showed
that carcass lipid of channel catfish (Gatlin and Stickney, 1982) and
muscle lipid content of European sea bass (Peres and Oliva-Teles,
1999) and hybrid striped bass (Gaylord and Gatlin, 2000) were not
affected by dietary lipid levels. Dietary levels of vitamin E had no effect
of body protein, ash and moisture, but body lipid significantly
increased in fish fed 100 mg/kg supplemental vitamin E. The
significant increase in body lipid of fish fed this diet could not be
explained since fish fed diets supplemented with 200 mg supplemental
vitamin E had similar body lipid as the group fed 50 mg
supplemental vitamin E. Watanabe et al. (1977) and Huang and
Huang (2004) reported that whole body proximate composition of
common carp (Cyprinus carpio) and hybrid tilapia, respectively was
unaffected by dietary levels of vitamin E.
Liver concentrations of α-tocopherol significantly increased at each
incremental level of dietary vitamin E. Similar findings have been
reported for other fish species (Boggio et al., 1985; Hamre et al., 1997;
Gatta et al., 2000; Chaiyapechara et al., 2003; Yildirim-Aksoy et al., 2008;
Limet al., in press). However, therewas a trend of decreasing liver levels
ofα-tocopherolwith increasing dietary lipid levels, and the value of this
variablewas significantly lower in fish fed the highest lipid levels (14%).
The decrease in tissue α-tocopherol content in fish fed increasing levels
of dietary lipid high in n−3 HUFA has also been observed in rainbow
trout (Oncorhynchus mykiss) (Cowey et al., 1984; Boggio et al., 1985),
Atlantic salmon (Salmo salar) (Hemre and Sandnes, 1999), blue tilapia
(Roemet al., 1990), turbot (Hypsopsetta gutulata) (Stephan et al., 1995)
and Japanese flounder (Wang et al., 2006). Itwas suggested that vitamin
Ewas increasingly utilized as an antioxidant to protect tissue lipids from
oxidation due to greater amounts of n−3 HUFA in tissues of fish fed
higher levels of dietary lipid.
Earlier studies have shown that Nile tilapia (Satoh et al., 1987),
halibut (Tocher, 2003) and gilthead sea bream (Sparus aurata)
(Mourento et al., 2002) fed diets without vitamin E supplementation
had significantly decreased HSI, likely due to tissue degeneration. It has
also been found that HSI value is correlated with the amount of fat
deposition in livers (Oguri, 1978; Bruslé and Anadon, 1996). Thus,
although liver lipid content was not determined in the present study,
the non-significant differences among HSI of fish in various treatments
may indicate that supplementation of 50 mg vitamin E/kg (112 mg/kg
total vitamin E) was sufficient to prevent degeneration and/or fat
infiltration of liver tissue in Nile tilapia fed diets containing6 to 14% lipid.
This level of dietary vitamin E was also adequate for normal formation
and development of blood cells as none of the hematological parameters
evaluated differed among treatments.
Numerous studies have been conducted on the role of dietary lipid
sources and essential fatty acids on the immune response and disease
resistance in fish, but few studies have dealt with dietary lipid levels
and fish health. However, published information on the effect of
dietary lipid and essential fatty acids on immune response and disease
resistance in fish is inconsistent and often contradictory (Lim et al.,2008). In the present study, enhanced serum protein concentrations
were observed in fish fed 14% lipid diets. This increase in serum
protein could be due to elevated lipoprotein levels required for the
transport of excess lipid. Serum alternative complement, however,
significantly decreased in fish fed 10 or 14% lipid diets. Likewise,
Yildirim-Aksoy et al. (2009) obtained significantly increased serum
protein and decreased serum complement in channel catfish fed a
commercial diet containing 5.6% lipid supplemented with 6% or 9%
menhaden fish oil. They also reported increased lysozyme activity in
catfish fed diets supplemented with 3 or 6% fish oil. We found,
however, that dietary lipid levels had no influence on lysozyme
activity of Nile tilapia.
Vitamin E, which is abundant in immune cell membranes (Beharka
et al., 1997), plays an important role in the fish immune response
(Waagbø, 1994). Peritoneal macrophage function was adversely
affected in rainbow trout (Blazer and Wolke, 1984) and channel catfish
(Wise et al., 1993) fed vitamin E-deficient diets. Deficiency of vitamin E
has been reported to reduce serum protein, serum globulin and
phagocyte activity in rainbow trout (Blazer and Wolke, 1984; Clerton
et al., 2001) and serum complement activity in Atlantic salmon (Hardie
et al., 1990), gilthead seabream (Tort et al., 1996; Montero et al., 1998)
and sea bass (Obach et al., 1993). Ortuno et al. (2000, 2001) reported
that serum complement and phagocytic activity in gilthead seabream
were correlated with dietary levels of vitamin E supplementation, but
neither leukocyte migration nor respiratory burst was affected. Lin and
Shiau (2005) also obtained significantly higher respiratory burst activity
and plasma lysozyme and alternative complement activity in grouper
(Epinephelus malabaricus) fed diets supplemented with vitamin E
ranging from 25 to 800 mg/kg diet than fish fed the unsupplemented
control diet. These values progressively increased with increasing levels
of dietary vitamin E. In Nile tilapia, Lim et al. (in press) found that
supplementation of 50 or 500 mg vitamin E to a basal diet containing
23.1 mg vitamin E/kg had no effect on serum protein, total immunoglobulin
and lysozyme activity, but alternative complement was
adversely affected at the vitamin E supplemental level of 500 mg/kg.
Data of the current study indicated that increasing supplemental levels
of vitamin E from50 mgto 100 or 200 mg/kg diet had no effect on serum
protein, but lysozyme and complement activity were stimulated at
vitamin E supplemental levels of 200 mg and 100 or 200 mg/kg diet,
respectively. Lysozyme activity has been reported to coincide to some
degree with a change in the number of the circulating leucocytes
(Fletcher and White, 1973; Muona and Soivio, 1992). In the current
study, since no difference was found in blood leukocyte count between
treatments, the lysozyme production by leukocytes could have been
enhanced at high supplemental levels of vitamin E.
Previous investigations have showed that vitamin E requirements of
fish are affected by dietary lipid levels (Watanabe et al., 1977; Lovell
et al., 1984; Satoh et al., 1987; Roemet al., 1990; Shiau and Shiau, 2001).
Results of the present study shown that, based on weight gain, FI, FER
and survival, vitamin E requirement of Nile tilapia was not affected by
dietary lipid levels and supplementation of 50 mg of vitamin E/kg diet
(analyzed values of 112 mg/kg) was sufficient for tilapia fed purified
diets containing an equal mixture of corn oil and menhaden fish oil
ranging from 6 to 14%. This value is higher than those determined by
Roem et al. (1990) for O. aureus (10 and 25 mg/kg of diet at 3 and 6%
dietary lipid, respectively, or 3 to 4 mg vitamin E per percent of corn oil)
and Shiau and Shiau (2001) for hybrid tilapia (O. niloticus×O. aureus)
(42–44 mg/kg and 60–66 mg/kg in diets containing 5% and 12% lipid,
respectively). These values, however, are considerably lower than the
requirement values of 50 to 100 mg/kg for a diet containing 5% lipid
(pollock liver oil) and 500 mg/kg for a diet containing 10 to 15% lipid
reported for Nile tilapia (Satoh et al., 1987).Whether the differences in
the degree of fatty acid unsaturation between the lipid source used in
this study and that of Satoh et al. (1987) contributed to the differences
in the vitamin E requirements cannot be ascertained. However, it has
been reported that, in fish, high levels of dietary highly unsaturated
fatty acids induced higher vitamin E requirements (Cowey et al.,
1983; Roem et al., 1990). It should be noted that our diets were also
supplemented with the antioxidant, ethoxyquin, at 200 mg/kg diet.
Ethoxyquin, although it has no biological activity of vitamin E, can
partially spare vitamin E in the diet for growth and other physiological
functions (Lovell et al., 1984).
The non-significant effect of increasing dietary lipid levels from 6
to 14% on weight gain, feed intake and survival was expected because
our test diets were isonitrogenous and isocaloric and contained
essential nutrients at levels that meet or exceed the know requirements
for tilapia. A number of earlier studies have reported similar
weight gain and FER of channel catfish, Ictalurus punctatus (Gatlin and
Stickney, 1982; Twibell and Wilson, 2003; Yildirim-Aksoy et al.,
2007), blue tilapia (O. aureus) (Roem et al., 1990) and European sea
bass (Dicentrarchus labrex) (Peres and Oliva-Teles, 1999) fed diets
supplemented with increasing levels of fish oil. The non-significant
effect of dietary fish oil levels on feed intake has also been reported for
channel catfish by Twibell and Wilson (2003) and Yildirim-Aksoy
et al. (2007). However, significantly lower FER in fish fed diets
supplemented with 14% lipid, regardless of dietary levels of vitamin E,
may be due to excessive levels of dietary lipid. Lim and Webster
(2006) reported that tilapia do not tolerate as high a dietary lipid as do
salmonids. A dietary lipid level in excess of 12% depressed growth of
juvenile O. aureus×O. niloticus hybrids (Jauncey and Ross, 1982;
Jauncey, 2000). Thus, for good FER, lipid levels in diets of Nile tilapia
juveniles should not exceed 10%.
Increasing supplemental lipid levels to 14% significantly increased
whole body lipid and decreased moisture, as has been reported for
several fish species fed increasing levels of dietary lipid (Jauncey and
Ross, 1982; Viola et al., 1988; De Silva et al., 1991; Stowell and Gatlin,
1992; Chou and Shiau, 1996; Peres and Oliva-Teles, 1999; Jauncey,
2000; Yildirim-Aksoy et al., 2007). Other studies, however, showed
that carcass lipid of channel catfish (Gatlin and Stickney, 1982) and
muscle lipid content of European sea bass (Peres and Oliva-Teles,
1999) and hybrid striped bass (Gaylord and Gatlin, 2000) were not
affected by dietary lipid levels. Dietary levels of vitamin E had no effect
of body protein, ash and moisture, but body lipid significantly
increased in fish fed 100 mg/kg supplemental vitamin E. The
significant increase in body lipid of fish fed this diet could not be
explained since fish fed diets supplemented with 200 mg supplemental
vitamin E had similar body lipid as the group fed 50 mg
supplemental vitamin E. Watanabe et al. (1977) and Huang and
Huang (2004) reported that whole body proximate composition of
common carp (Cyprinus carpio) and hybrid tilapia, respectively was
unaffected by dietary levels of vitamin E.
Liver concentrations of α-tocopherol significantly increased at each
incremental level of dietary vitamin E. Similar findings have been
reported for other fish species (Boggio et al., 1985; Hamre et al., 1997;
Gatta et al., 2000; Chaiyapechara et al., 2003; Yildirim-Aksoy et al., 2008;
Limet al., in press). However, therewas a trend of decreasing liver levels
ofα-tocopherolwith increasing dietary lipid levels, and the value of this
variablewas significantly lower in fish fed the highest lipid levels (14%).
The decrease in tissue α-tocopherol content in fish fed increasing levels
of dietary lipid high in n−3 HUFA has also been observed in rainbow
trout (Oncorhynchus mykiss) (Cowey et al., 1984; Boggio et al., 1985),
Atlantic salmon (Salmo salar) (Hemre and Sandnes, 1999), blue tilapia
(Roemet al., 1990), turbot (Hypsopsetta gutulata) (Stephan et al., 1995)
and Japanese flounder (Wang et al., 2006). Itwas suggested that vitamin
Ewas increasingly utilized as an antioxidant to protect tissue lipids from
oxidation due to greater amounts of n−3 HUFA in tissues of fish fed
higher levels of dietary lipid.
Earlier studies have shown that Nile tilapia (Satoh et al., 1987),
halibut (Tocher, 2003) and gilthead sea bream (Sparus aurata)
(Mourento et al., 2002) fed diets without vitamin E supplementation
had significantly decreased HSI, likely due to tissue degeneration. It has
also been found that HSI value is correlated with the amount of fat
deposition in livers (Oguri, 1978; Bruslé and Anadon, 1996). Thus,
although liver lipid content was not determined in the present study,
the non-significant differences among HSI of fish in various treatments
may indicate that supplementation of 50 mg vitamin E/kg (112 mg/kg
total vitamin E) was sufficient to prevent degeneration and/or fat
infiltration of liver tissue in Nile tilapia fed diets containing6 to 14% lipid.
This level of dietary vitamin E was also adequate for normal formation
and development of blood cells as none of the hematological parameters
evaluated differed among treatments.
Numerous studies have been conducted on the role of dietary lipid
sources and essential fatty acids on the immune response and disease
resistance in fish, but few studies have dealt with dietary lipid levels
and fish health. However, published information on the effect of
dietary lipid and essential fatty acids on immune response and disease
resistance in fish is inconsistent and often contradictory (Lim et al.,2008). In the present study, enhanced serum protein concentrations
were observed in fish fed 14% lipid diets. This increase in serum
protein could be due to elevated lipoprotein levels required for the
transport of excess lipid. Serum alternative complement, however,
significantly decreased in fish fed 10 or 14% lipid diets. Likewise,
Yildirim-Aksoy et al. (2009) obtained significantly increased serum
protein and decreased serum complement in channel catfish fed a
commercial diet containing 5.6% lipid supplemented with 6% or 9%
menhaden fish oil. They also reported increased lysozyme activity in
catfish fed diets supplemented with 3 or 6% fish oil. We found,
however, that dietary lipid levels had no influence on lysozyme
activity of Nile tilapia.
Vitamin E, which is abundant in immune cell membranes (Beharka
et al., 1997), plays an important role in the fish immune response
(Waagbø, 1994). Peritoneal macrophage function was adversely
affected in rainbow trout (Blazer and Wolke, 1984) and channel catfish
(Wise et al., 1993) fed vitamin E-deficient diets. Deficiency of vitamin E
has been reported to reduce serum protein, serum globulin and
phagocyte activity in rainbow trout (Blazer and Wolke, 1984; Clerton
et al., 2001) and serum complement activity in Atlantic salmon (Hardie
et al., 1990), gilthead seabream (Tort et al., 1996; Montero et al., 1998)
and sea bass (Obach et al., 1993). Ortuno et al. (2000, 2001) reported
that serum complement and phagocytic activity in gilthead seabream
were correlated with dietary levels of vitamin E supplementation, but
neither leukocyte migration nor respiratory burst was affected. Lin and
Shiau (2005) also obtained significantly higher respiratory burst activity
and plasma lysozyme and alternative complement activity in grouper
(Epinephelus malabaricus) fed diets supplemented with vitamin E
ranging from 25 to 800 mg/kg diet than fish fed the unsupplemented
control diet. These values progressively increased with increasing levels
of dietary vitamin E. In Nile tilapia, Lim et al. (in press) found that
supplementation of 50 or 500 mg vitamin E to a basal diet containing
23.1 mg vitamin E/kg had no effect on serum protein, total immunoglobulin
and lysozyme activity, but alternative complement was
adversely affected at the vitamin E supplemental level of 500 mg/kg.
Data of the current study indicated that increasing supplemental levels
of vitamin E from50 mgto 100 or 200 mg/kg diet had no effect on serum
protein, but lysozyme and complement activity were stimulated at
vitamin E supplemental levels of 200 mg and 100 or 200 mg/kg diet,
respectively. Lysozyme activity has been reported to coincide to some
degree with a change in the number of the circulating leucocytes
(Fletcher and White, 1973; Muona and Soivio, 1992). In the current
study, since no difference was found in blood leukocyte count between
treatments, the lysozyme production by leukocytes could have been
enhanced at high supplemental levels of vitamin E.
0/5000
4. DiscussionPrevious investigations have showed that vitamin E requirements offish are affected by dietary lipid levels (Watanabe et al., 1977; Lovellet al., 1984; Satoh et al., 1987; Roemet al., 1990; Shiau and Shiau, 2001).Results of the present study shown that, based on weight gain, FI, FERand survival, vitamin E requirement of Nile tilapia was not affected bydietary lipid levels and supplementation of 50 mg of vitamin E/kg diet(analyzed values of 112 mg/kg) was sufficient for tilapia fed purifieddiets containing an equal mixture of corn oil and menhaden fish oilranging from 6 to 14%. This value is higher than those determined byRoem et al. (1990) for O. aureus (10 and 25 mg/kg of diet at 3 and 6%dietary lipid, respectively, or 3 to 4 mg vitamin E per percent of corn oil)and Shiau and Shiau (2001) for hybrid tilapia (O. niloticus×O. aureus)(42–44 mg/kg and 60–66 mg/kg in diets containing 5% and 12% lipid,respectively). These values, however, are considerably lower than therequirement values of 50 to 100 mg/kg for a diet containing 5% lipid(pollock liver oil) and 500 mg/kg for a diet containing 10 to 15% lipidreported for Nile tilapia (Satoh et al., 1987).Whether the differences inthe degree of fatty acid unsaturation between the lipid source used inthis study and that of Satoh et al. (1987) contributed to the differencesin the vitamin E requirements cannot be ascertained. However, it hasbeen reported that, in fish, high levels of dietary highly unsaturatedfatty acids induced higher vitamin E requirements (Cowey et al.,1983; Roem et al., 1990). It should be noted that our diets were alsosupplemented with the antioxidant, ethoxyquin, at 200 mg/kg diet.Ethoxyquin, although it has no biological activity of vitamin E, canpartially spare vitamin E in the diet for growth and other physiologicalfunctions (Lovell et al., 1984).The non-significant effect of increasing dietary lipid levels from 6to 14% on weight gain, feed intake and survival was expected becauseour test diets were isonitrogenous and isocaloric and containedessential nutrients at levels that meet or exceed the know requirementsfor tilapia. A number of earlier studies have reported similarweight gain and FER of channel catfish, Ictalurus punctatus (Gatlin andStickney, 1982; Twibell and Wilson, 2003; Yildirim-Aksoy et al.,2007), blue tilapia (O. aureus) (Roem et al., 1990) and European seabass (Dicentrarchus labrex) (Peres and Oliva-Teles, 1999) fed dietssupplemented with increasing levels of fish oil. The non-significanteffect of dietary fish oil levels on feed intake has also been reported forchannel catfish by Twibell and Wilson (2003) and Yildirim-Aksoyet al. (2007). However, significantly lower FER in fish fed dietssupplemented with 14% lipid, regardless of dietary levels of vitamin E,may be due to excessive levels of dietary lipid. Lim and Webster(2006) reported that tilapia do not tolerate as high a dietary lipid as dosalmonids. A dietary lipid level in excess of 12% depressed growth ofjuvenile O. aureus×O. niloticus hybrids (Jauncey and Ross, 1982;Jauncey, 2000). Thus, for good FER, lipid levels in diets of Nile tilapiajuveniles should not exceed 10%.Increasing supplemental lipid levels to 14% significantly increasedwhole body lipid and decreased moisture, as has been reported forseveral fish species fed increasing levels of dietary lipid (Jauncey andRoss, 1982; Viola et al., 1988; De Silva et al., 1991; Stowell and Gatlin,1992; Chou and Shiau, 1996; Peres and Oliva-Teles, 1999; Jauncey,2000; Yildirim-Aksoy et al., 2007). Other studies, however, showedthat carcass lipid of channel catfish (Gatlin and Stickney, 1982) andmuscle lipid content of European sea bass (Peres and Oliva-Teles,1999) and hybrid striped bass (Gaylord and Gatlin, 2000) were notaffected by dietary lipid levels. Dietary levels of vitamin E had no effectof body protein, ash and moisture, but body lipid significantlyincreased in fish fed 100 mg/kg supplemental vitamin E. Thesignificant increase in body lipid of fish fed this diet could not beexplained since fish fed diets supplemented with 200 mg supplementalvitamin E had similar body lipid as the group fed 50 mgsupplemental vitamin E. Watanabe et al. (1977) and Huang andHuang (2004) reported that whole body proximate composition ofcommon carp (Cyprinus carpio) and hybrid tilapia, respectively wasunaffected by dietary levels of vitamin E.Liver concentrations of α-tocopherol significantly increased at eachincremental level of dietary vitamin E. Similar findings have beenreported for other fish species (Boggio et al., 1985; Hamre et al., 1997;Gatta et al., 2000; Chaiyapechara et al., 2003; Yildirim-Aksoy et al., 2008;Limet al., in press). However, therewas a trend of decreasing liver levelsofα-tocopherolwith increasing dietary lipid levels, and the value of thisvariablewas significantly lower in fish fed the highest lipid levels (14%).The decrease in tissue α-tocopherol content in fish fed increasing levelsof dietary lipid high in n−3 HUFA has also been observed in rainbowtrout (Oncorhynchus mykiss) (Cowey et al., 1984; Boggio et al., 1985),Atlantic salmon (Salmo salar) (Hemre and Sandnes, 1999), blue tilapia(Roemet al., 1990), turbot (Hypsopsetta gutulata) (Stephan et al., 1995)and Japanese flounder (Wang et al., 2006). Itwas suggested that vitaminEwas increasingly utilized as an antioxidant to protect tissue lipids fromoxidation due to greater amounts of n−3 HUFA in tissues of fish fedhigher levels of dietary lipid.Earlier studies have shown that Nile tilapia (Satoh et al., 1987),halibut (Tocher, 2003) and gilthead sea bream (Sparus aurata)(Mourento et al., 2002) fed diets without vitamin E supplementationhad significantly decreased HSI, likely due to tissue degeneration. It hasalso been found that HSI value is correlated with the amount of fatdeposition in livers (Oguri, 1978; Bruslé and Anadon, 1996). Thus,although liver lipid content was not determined in the present study,the non-significant differences among HSI of fish in various treatmentsmay indicate that supplementation of 50 mg vitamin E/kg (112 mg/kgtotal vitamin E) was sufficient to prevent degeneration and/or fatinfiltration of liver tissue in Nile tilapia fed diets containing6 to 14% lipid.This level of dietary vitamin E was also adequate for normal formationand development of blood cells as none of the hematological parametersevaluated differed among treatments.Numerous studies have been conducted on the role of dietary lipidsources and essential fatty acids on the immune response and diseaseresistance in fish, but few studies have dealt with dietary lipid levelsand fish health. However, published information on the effect ofdietary lipid and essential fatty acids on immune response and diseaseresistance in fish is inconsistent and often contradictory (Lim et al.,2008). In the present study, enhanced serum protein concentrationswere observed in fish fed 14% lipid diets. This increase in serumprotein could be due to elevated lipoprotein levels required for thetransport of excess lipid. Serum alternative complement, however,significantly decreased in fish fed 10 or 14% lipid diets. Likewise,
Yildirim-Aksoy et al. (2009) obtained significantly increased serum
protein and decreased serum complement in channel catfish fed a
commercial diet containing 5.6% lipid supplemented with 6% or 9%
menhaden fish oil. They also reported increased lysozyme activity in
catfish fed diets supplemented with 3 or 6% fish oil. We found,
however, that dietary lipid levels had no influence on lysozyme
activity of Nile tilapia.
Vitamin E, which is abundant in immune cell membranes (Beharka
et al., 1997), plays an important role in the fish immune response
(Waagbø, 1994). Peritoneal macrophage function was adversely
affected in rainbow trout (Blazer and Wolke, 1984) and channel catfish
(Wise et al., 1993) fed vitamin E-deficient diets. Deficiency of vitamin E
has been reported to reduce serum protein, serum globulin and
phagocyte activity in rainbow trout (Blazer and Wolke, 1984; Clerton
et al., 2001) and serum complement activity in Atlantic salmon (Hardie
et al., 1990), gilthead seabream (Tort et al., 1996; Montero et al., 1998)
and sea bass (Obach et al., 1993). Ortuno et al. (2000, 2001) reported
that serum complement and phagocytic activity in gilthead seabream
were correlated with dietary levels of vitamin E supplementation, but
neither leukocyte migration nor respiratory burst was affected. Lin and
Shiau (2005) also obtained significantly higher respiratory burst activity
and plasma lysozyme and alternative complement activity in grouper
(Epinephelus malabaricus) fed diets supplemented with vitamin E
ranging from 25 to 800 mg/kg diet than fish fed the unsupplemented
control diet. These values progressively increased with increasing levels
of dietary vitamin E. In Nile tilapia, Lim et al. (in press) found that
supplementation of 50 or 500 mg vitamin E to a basal diet containing
23.1 mg vitamin E/kg had no effect on serum protein, total immunoglobulin
and lysozyme activity, but alternative complement was
adversely affected at the vitamin E supplemental level of 500 mg/kg.
Data of the current study indicated that increasing supplemental levels
of vitamin E from50 mgto 100 or 200 mg/kg diet had no effect on serum
protein, but lysozyme and complement activity were stimulated at
vitamin E supplemental levels of 200 mg and 100 or 200 mg/kg diet,
respectively. Lysozyme activity has been reported to coincide to some
degree with a change in the number of the circulating leucocytes
(Fletcher and White, 1973; Muona and Soivio, 1992). In the current
study, since no difference was found in blood leukocyte count between
treatments, the lysozyme production by leukocytes could have been
enhanced at high supplemental levels of vitamin E.
Yildirim-Aksoy et al. (2009) obtained significantly increased serum
protein and decreased serum complement in channel catfish fed a
commercial diet containing 5.6% lipid supplemented with 6% or 9%
menhaden fish oil. They also reported increased lysozyme activity in
catfish fed diets supplemented with 3 or 6% fish oil. We found,
however, that dietary lipid levels had no influence on lysozyme
activity of Nile tilapia.
Vitamin E, which is abundant in immune cell membranes (Beharka
et al., 1997), plays an important role in the fish immune response
(Waagbø, 1994). Peritoneal macrophage function was adversely
affected in rainbow trout (Blazer and Wolke, 1984) and channel catfish
(Wise et al., 1993) fed vitamin E-deficient diets. Deficiency of vitamin E
has been reported to reduce serum protein, serum globulin and
phagocyte activity in rainbow trout (Blazer and Wolke, 1984; Clerton
et al., 2001) and serum complement activity in Atlantic salmon (Hardie
et al., 1990), gilthead seabream (Tort et al., 1996; Montero et al., 1998)
and sea bass (Obach et al., 1993). Ortuno et al. (2000, 2001) reported
that serum complement and phagocytic activity in gilthead seabream
were correlated with dietary levels of vitamin E supplementation, but
neither leukocyte migration nor respiratory burst was affected. Lin and
Shiau (2005) also obtained significantly higher respiratory burst activity
and plasma lysozyme and alternative complement activity in grouper
(Epinephelus malabaricus) fed diets supplemented with vitamin E
ranging from 25 to 800 mg/kg diet than fish fed the unsupplemented
control diet. These values progressively increased with increasing levels
of dietary vitamin E. In Nile tilapia, Lim et al. (in press) found that
supplementation of 50 or 500 mg vitamin E to a basal diet containing
23.1 mg vitamin E/kg had no effect on serum protein, total immunoglobulin
and lysozyme activity, but alternative complement was
adversely affected at the vitamin E supplemental level of 500 mg/kg.
Data of the current study indicated that increasing supplemental levels
of vitamin E from50 mgto 100 or 200 mg/kg diet had no effect on serum
protein, but lysozyme and complement activity were stimulated at
vitamin E supplemental levels of 200 mg and 100 or 200 mg/kg diet,
respectively. Lysozyme activity has been reported to coincide to some
degree with a change in the number of the circulating leucocytes
(Fletcher and White, 1973; Muona and Soivio, 1992). In the current
study, since no difference was found in blood leukocyte count between
treatments, the lysozyme production by leukocytes could have been
enhanced at high supplemental levels of vitamin E.
การแปล กรุณารอสักครู่..
4 . การอภิปราย
ก่อนหน้านี้ได้พบว่า วิตามิน E ความต้องการของ
ปลาได้รับผลกระทบจากระดับของไขมันใยอาหาร ( วาตานาเบะ et al . , 1977 ; โลเวลล์
et al . , 1984 ; ซาโต้ et al . , 1987 ; roemet al . , 1990 ; shiau และ shiau , 2001 ) .
ผลการศึกษาพบว่า ขึ้นอยู่กับน้ำหนัก , FI , Fer
การอยู่รอดและ วิตามิน E ความต้องการของปลานิลที่ได้รับผลกระทบ โดย
อาหารไขมันและระดับการเสริมวิตามินอี 50 มิลลิกรัม / กิโลกรัมอาหาร
( วิเคราะห์คุณค่าของ 112 มิลลิกรัม / กิโลกรัม ) ก็เพียงพอสำหรับปลานิลที่ได้รับอาหารที่มีโปรตีน
ผสมเท่ากันของน้ำมันข้าวโพดและน้ำมันปลาเมนฮาเดน
ตั้งแต่ 6 ถึง 14 % ค่าสูงกว่าที่กำหนดโดย
roem et al . ( 1990 ) o . aureus ( 10 และ 25 มิลลิกรัมต่อกิโลกรัมของอาหารที่ 3 และ 6 %
อาหารไขมันตามลำดับหรือ 3 ถึง 4 มก. วิตามินอีต่อร้อยละของน้ำมันข้าวโพด )
shiau และ shiau ( 2001 ) และ ปลานิลลูกผสม ( O . niloticus × . aureus )
( 42 - 44 มก. / กก. และ 60 – 66 มิลลิกรัมต่อกิโลกรัมในอาหารที่ประกอบด้วย 5 % และ 12 % ของ
ตามลำดับ ) ค่าเหล่านี้ แต่จะต่ำกว่าค่าความต้องการ
50 ถึง 100 มิลลิกรัม / กิโลกรัม สำหรับอาหารที่มีไขมัน
5 เปอร์เซ็นต์( น้ำมันตับ Pollock ) และ 500 มิลลิกรัม / กิโลกรัม สำหรับอาหารที่ประกอบด้วย 10 ถึง 15 % ไขมัน
รายงานปลานิล ( ซาโต้ et al . , 1987 ) ไม่ว่ากัน
ระดับของไม่อิ่มตัวกรดไขมันระหว่างแหล่งไขมันที่ใช้ในการศึกษานี้และของ
ซาโต้ et al . ( 1987 ) ส่วนความแตกต่าง
ในวิตามินอีความต้องการไม่สามารถตรวจสอบให้ชัดเจนก่อน แต่มันมี
ได้รับรายงานว่าในปลาระดับของใยอาหารสูงไม่อิ่มตัวกรดไขมันและวิตามินอี
สูงกว่าความต้องการ ( cowey et al . ,
1983 ; roem et al . , 1990 ) มันควรจะสังเกตว่าอาหารของเรายัง
เสริมกับทอกซีควินสารต้านอนุมูลอิสระที่ 200 มิลลิกรัมต่อกิโลกรัมอาหาร
ทอกซีควิน , แม้ว่าจะไม่มีฤทธิ์ทางชีวภาพของวิตามิน E ,
บางส่วนอะไหล่วิตามินอีในอาหารต่อการเจริญเติบโตและสรีรวิทยา
อื่น ๆฟังก์ชัน ( โลเวลล์ et al . , 1984 ) .
ไม่ใช่ผลของการเพิ่มระดับไขมันจากอาหาร 6
14 เปอร์เซ็นต์น้ำหนักตัว ปริมาณอาหารที่กินและความอยู่รอด คาด เพราะตัวเลี้ยงด้วยอาหารทดลองของเรา
ที่สำคัญคือมีสารอาหารในระดับที่ตรงกับ หรือเกินกว่าความต้องการ
สำหรับปลานิล จำนวนของการศึกษาก่อนหน้านี้มีรายงานที่คล้ายกัน
ก่อนหน้านี้ได้พบว่า วิตามิน E ความต้องการของ
ปลาได้รับผลกระทบจากระดับของไขมันใยอาหาร ( วาตานาเบะ et al . , 1977 ; โลเวลล์
et al . , 1984 ; ซาโต้ et al . , 1987 ; roemet al . , 1990 ; shiau และ shiau , 2001 ) .
ผลการศึกษาพบว่า ขึ้นอยู่กับน้ำหนัก , FI , Fer
การอยู่รอดและ วิตามิน E ความต้องการของปลานิลที่ได้รับผลกระทบ โดย
อาหารไขมันและระดับการเสริมวิตามินอี 50 มิลลิกรัม / กิโลกรัมอาหาร
( วิเคราะห์คุณค่าของ 112 มิลลิกรัม / กิโลกรัม ) ก็เพียงพอสำหรับปลานิลที่ได้รับอาหารที่มีโปรตีน
ผสมเท่ากันของน้ำมันข้าวโพดและน้ำมันปลาเมนฮาเดน
ตั้งแต่ 6 ถึง 14 % ค่าสูงกว่าที่กำหนดโดย
roem et al . ( 1990 ) o . aureus ( 10 และ 25 มิลลิกรัมต่อกิโลกรัมของอาหารที่ 3 และ 6 %
อาหารไขมันตามลำดับหรือ 3 ถึง 4 มก. วิตามินอีต่อร้อยละของน้ำมันข้าวโพด )
shiau และ shiau ( 2001 ) และ ปลานิลลูกผสม ( O . niloticus × . aureus )
( 42 - 44 มก. / กก. และ 60 – 66 มิลลิกรัมต่อกิโลกรัมในอาหารที่ประกอบด้วย 5 % และ 12 % ของ
ตามลำดับ ) ค่าเหล่านี้ แต่จะต่ำกว่าค่าความต้องการ
50 ถึง 100 มิลลิกรัม / กิโลกรัม สำหรับอาหารที่มีไขมัน
5 เปอร์เซ็นต์( น้ำมันตับ Pollock ) และ 500 มิลลิกรัม / กิโลกรัม สำหรับอาหารที่ประกอบด้วย 10 ถึง 15 % ไขมัน
รายงานปลานิล ( ซาโต้ et al . , 1987 ) ไม่ว่ากัน
ระดับของไม่อิ่มตัวกรดไขมันระหว่างแหล่งไขมันที่ใช้ในการศึกษานี้และของ
ซาโต้ et al . ( 1987 ) ส่วนความแตกต่าง
ในวิตามินอีความต้องการไม่สามารถตรวจสอบให้ชัดเจนก่อน แต่มันมี
ได้รับรายงานว่าในปลาระดับของใยอาหารสูงไม่อิ่มตัวกรดไขมันและวิตามินอี
สูงกว่าความต้องการ ( cowey et al . ,
1983 ; roem et al . , 1990 ) มันควรจะสังเกตว่าอาหารของเรายัง
เสริมกับทอกซีควินสารต้านอนุมูลอิสระที่ 200 มิลลิกรัมต่อกิโลกรัมอาหาร
ทอกซีควิน , แม้ว่าจะไม่มีฤทธิ์ทางชีวภาพของวิตามิน E ,
บางส่วนอะไหล่วิตามินอีในอาหารต่อการเจริญเติบโตและสรีรวิทยา
อื่น ๆฟังก์ชัน ( โลเวลล์ et al . , 1984 ) .
ไม่ใช่ผลของการเพิ่มระดับไขมันจากอาหาร 6
14 เปอร์เซ็นต์น้ำหนักตัว ปริมาณอาหารที่กินและความอยู่รอด คาด เพราะตัวเลี้ยงด้วยอาหารทดลองของเรา
ที่สำคัญคือมีสารอาหารในระดับที่ตรงกับ หรือเกินกว่าความต้องการ
สำหรับปลานิล จำนวนของการศึกษาก่อนหน้านี้มีรายงานที่คล้ายกัน
การแปล กรุณารอสักครู่..
ภาษาอื่น ๆ
การสนับสนุนเครื่องมือแปลภาษา: กรีก, กันนาดา, กาลิเชียน, คลิงออน, คอร์สิกา, คาซัค, คาตาลัน, คินยารวันดา, คีร์กิซ, คุชราต, จอร์เจีย, จีน, จีนดั้งเดิม, ชวา, ชิเชวา, ซามัว, ซีบัวโน, ซุนดา, ซูลู, ญี่ปุ่น, ดัตช์, ตรวจหาภาษา, ตุรกี, ทมิฬ, ทาจิก, ทาทาร์, นอร์เวย์, บอสเนีย, บัลแกเรีย, บาสก์, ปัญจาป, ฝรั่งเศส, พาชตู, ฟริเชียน, ฟินแลนด์, ฟิลิปปินส์, ภาษาอินโดนีเซี, มองโกเลีย, มัลทีส, มาซีโดเนีย, มาราฐี, มาลากาซี, มาลายาลัม, มาเลย์, ม้ง, ยิดดิช, ยูเครน, รัสเซีย, ละติน, ลักเซมเบิร์ก, ลัตเวีย, ลาว, ลิทัวเนีย, สวาฮิลี, สวีเดน, สิงหล, สินธี, สเปน, สโลวัก, สโลวีเนีย, อังกฤษ, อัมฮาริก, อาร์เซอร์ไบจัน, อาร์เมเนีย, อาหรับ, อิกโบ, อิตาลี, อุยกูร์, อุสเบกิสถาน, อูรดู, ฮังการี, ฮัวซา, ฮาวาย, ฮินดี, ฮีบรู, เกลิกสกอต, เกาหลี, เขมร, เคิร์ด, เช็ก, เซอร์เบียน, เซโซโท, เดนมาร์ก, เตลูกู, เติร์กเมน, เนปาล, เบงกอล, เบลารุส, เปอร์เซีย, เมารี, เมียนมา (พม่า), เยอรมัน, เวลส์, เวียดนาม, เอสเปอแรนโต, เอสโทเนีย, เฮติครีโอล, แอฟริกา, แอลเบเนีย, โคซา, โครเอเชีย, โชนา, โซมาลี, โปรตุเกส, โปแลนด์, โยรูบา, โรมาเนีย, โอเดีย (โอริยา), ไทย, ไอซ์แลนด์, ไอร์แลนด์, การแปลภาษา.
- ล้างจาน
- เป็นเรื่องที่เก็บไว้ในใจนานแล้ว
- One hundred and tenth chapter terrible s
- ฉันฝึกทำอาหาร
- ที่ฉันรู้ตอนนี้ฉันเหนื่อยกับDexมาก
- Hello! happy birth day my friend. I wish
- what's the matter with you?
- ตรวจสอบคะแนนสะสม บัวหลวง Thank You Rewar
- มันง่ายต่อการเช็คข้อมูล เพราะว่าตอนนี้ฉั
- Quiet
- Would you like to study
- spirit
- ไปกี่วัน
- Phu Phan Royal Development Study Centre
- vibration
- ป่วยหนัก
- Assignment of costs:
- Multy-seed Chips 550 grams
- ฉันลางานหนึ่งวัน
- ขาหมูน้ำแดง
- แพร่กระจาย
- 吃了苹果就跑
- สู่โลกที่สดใจ
- โปรดติดตามตอนต่อไป
