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Effects of dietary phytic acid on organic and inorganic zinc utilization in juvenile hybrid tilapia (Oreochromis niloticus × O. aureus)
|Authors: ||Hsi-Yuan Chen|
|Contributors: ||NTOU:Department of Food Science|
organic Zn;inorganic Zn;phytic acid;tilapia
|Issue Date: ||2013-10-07T02:49:54Z
|Abstract: ||本實驗探討吳郭魚其飼料中含植酸時對有機態鋅(Zinc-peptide) 與無機態鋅(ZnSO4) 之利用性，魚體成長、免疫反應以及全魚體、血漿、肝臟及脊椎骨中鋅、銅、鎂、鐵、鈣濃度之影響。實驗飼料中鋅含量係以本實驗室過去以有機態鋅(Zn-peptide)與無機態鋅(ZnSO4)分別所定量之吳郭魚鋅需求量，即10 mg Zn/kg diet (Zn-peptide)及30 mg Zn/kg diet (ZnSO4)，作為基礎(適量)。於含1.5%植酸之基礎飼料中，分別添加適量、5倍適量及10倍適量之有機態鋅或無機態鋅，另以不含植酸含適量有機態鋅或無機態鋅組作為對照，總共8個實驗組，分別餵食吳郭魚稚魚 (平均初重1.43±0.02g) 八週 。結果顯示：鋅來源為無機態時，吳郭魚之增重率及肝臟鋅含量以不含植酸之適量鋅組顯著(P<0.05)高於含植酸之其他各組；血漿溶菌酶及紅血球含量以含植酸之10倍適量鋅組高於其他各組；超氧陰離子產率、血漿鋅含量及白血球含量以不含植酸之適量鋅組及含植酸之10倍適量鋅組顯著高於含植酸之適量鋅組；肝臟銅鋅超氧歧化酶各組間無差異。鋅來源為有機態時，吳郭魚之增重率、白血球含量、紅血球含量、血漿鋅含量、超氧陰離子產率、血漿溶菌酶活性在各組之間皆無差異；肝臟鋅含量以含植酸之適量鋅組及不含植酸之適量鋅組為最低；肝臟銅鋅超氧歧化酶以不含植酸之適量鋅組及含有植酸之10倍適量鋅組高於含植酸之適量鋅組。吳郭魚餵食飼料無論其鋅為無機態或有機態來源及其含量若干，飼料效率、蛋白質效率、肝體比及體組成皆無差異。吳郭魚餵食含植酸及適量鋅飼料，魚體之白血球計數、紅血球計數、血比容、血紅素濃度、血漿鋅含量、全魚體鋅、鎂及鈣含量、超氧陰離子產率及溶菌酶活性皆以有機態鋅組高於無機態鋅組。本實驗顯示吳郭魚餵食含1.5%植酸飼料，抑制其對無機態鋅之利用，添加10倍適量之鋅可改善植酸之抑制作用；鋅來源為有機態時，植酸對鋅利用之影響較小。飼料含1.5%植酸及適量鋅時，餵食有機態鋅組魚體之成長、組織鋅含量及免疫反應皆優於無機態鋅組。|
The purpose of this study was to elucidate the effects of dietary phytic acid on zinc (Zn) utilization in juvenile hybrid tilapia (Oreochromis niloticus × O. aureus). The optimum dietary Zn requirements (NZn) was quantified for the species previously with organic Zn (Zn amino acid complex, Zn-AA) and inorganic Zn (ZnSO4) as 10 mg Zn/kg and 30 mg Zn/kg, respectively. In this study, basal diet with 1.5% phytic acid was supplemented with optimum, 5X optimum and 10X optimum level of Zn-AA or ZnSO4; basal diet without phytic acid but supplemented with either optimum Zn-AA or optimum ZnSO4 were included as comparison. There were total eight experimental groups, each was fed to triplicate groups of tilapia (mean initial body weight 1.43±0.02 g) for eight weeks. In the inorganic Zn supplementation groups, fish fed the diet without phytic acid supplemented with optimum Zn had significantly (P<0.05) higher weight gain and hepatic Zn concentration than fish fed diet with phytic acid; fish fed diet with phytic acid supplemented with 10X-NZn had higher plasma lysozyme activity and red blood cell (RBC) count than the other dietary treatments; fish fed diet without phytic acid supplemented with NZn and diet with phytic acid supplemented with 10X-NZn had higher superoxide anion production ratio, plasma zinc concentration and white blood cell (WBC) than fish fed diet with phytic acid supplemented with NZn; Copper-zinc superoxide diemutase (CuZn-SOD) activity were similar in all dietary groups. In the organic Zn supplementation groups, weight gain, WBC, RBC, plasma and whole body Zn concentration, superoxide anion production ratio and plasma lysozyme activity were similar in all dietary groups; fish fed diet with or without phytic acid supplemented with NZn had lower hepatic Zn concentration than the other dietary groups; fish fed diet without phytic acid supplemented with NZn had higher copper-zinc superoxide diemutase (CuZn-SOD) activity than fish fed diet with phytic acid supplemented with NZn. Feed efficiency, protein efficiency ratio and hepatosomatic index of the fish were not different regardless of Zn source or supplementation level. Diet containing phytic acid at NZn supplementation level, fish fed diet with Zn-AA had higher WBC, RBC, Hct and Hb concentration, whole body Zn, magnesium and iron concentrations, superoxide anion production ratio and plasma lysozyme activity than fish fed diet with ZnSO4. This study demonstrates that tilapia fed diet with 1.5% phytic acid decrease inorganic zinc (ZnSO4) utilization, increasing Zn supplementation level (10X ZnSO4) may offset the phytic acid lowering Zn utilization effect; at optimum Zn supplememtation level, organic Zn is better utilized than inorganic Zn.
|Appears in Collections:||[食品科學系] 博碩士論文|
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