飼料含植酸對吳郭魚稚魚有機態和無機態銅利用性之影響

Effects of dietary phytic acid on organic and inorganic copper utilization in juvenile hybrid tilapia, Oreochromis niloticus × O. aureus

施仲蔚(Chung-Wei Shih)

指導教授 ： 林鈺鴻

國立屏東科技大學/農學院/水產養殖系所/碩士(2016年)

摘要

本研究目的為探討飼料中植酸對吳郭魚稚魚有機態銅(Cu amino acid complex)與無機態銅(CuSO4)利用性之影響。實驗一，以酪蛋白作為基礎飼料蛋白來源，飼料銅含量參考先前吳郭魚以有機態和無機態銅所訂定之最適銅需求量(10 mg Cu/kg有機態銅; 4 mg Cu/kg無機態銅)所設計。基礎飼料含15 g/kg植酸，分別添加適量、5倍適量及10倍適量有機態銅(10, 50, 100 mg Cu/kg)與無機態銅(4, 20, 40 mg Cu/kg)，並以不含植酸之適量有機態與無機態銅飼料作為對照組，共分為8組，每組3重複，分別餵予初重0.99±0.01 g之吳郭魚稚魚，實驗為期8週。結果顯示無論植酸添加與否、銅型態及添加量為何，各組吳郭魚之成長表現、全魚體組成、免疫反應、藍胞漿素活性及背肌與骨骼礦物質濃度均無顯著差異(P>0.05)。當銅來源為有機態銅時，吳郭魚餵食10倍適量銅其存活率、肝體比、血比容均顯著低於(P<0.05)其餘各組。無論銅型態為何，全魚體及肝臟銅濃度皆隨飼料中銅添加量增加而上升。實驗一結果證明飼料含15 g/kg植酸並不影響吳郭魚之成長表現、生理反應及組織礦物質濃度。實驗二，以豆粉作為飼料蛋白質來源，探討豆粉所含植酸對吳郭魚有機態與無機態銅利用性之影響。不添加銅之豆粉基礎飼料實際含6.9 mg Cu/kg及15.8 g/kg植酸，再分別於基礎飼料添加有機態與無機態銅4、8、12 mg Cu/kg，加上不添加銅之控制組，共計7組，每組3重複，分別餵予初重0.73±0.01 g之吳郭魚稚魚，實驗為期8週。結果顯示無論銅型態或添加量為何，均不影響吳郭魚成長表現、血液指標、免疫反應、藍胞漿素活性、全魚體組成及肝臟銅濃度。全魚體銅濃度雖不受銅來源影響，但隨飼料銅添加量上升時，全魚體銅濃度隨之增加。實驗二證實豆粉所含之植酸，並不影響吳郭魚對有機態與無機態銅的利用，且不添加銅之基礎飼料中含6.9 mg Cu/kg，已可滿足吳郭魚對銅之需求。綜合兩個實驗結果，證實當飼料含植酸時，並不影響吳郭魚對有機態和無機態銅的利用。

關鍵字

吳郭魚 ； 植酸 ； 有機態銅 ； 無機態銅

並列摘要

The study was aimed to investigate the effects of dietary phytic acid on organic and inorganic copper (Cu) utilization by juvenile hybrid tilapia (Oreochromis niloticus × O. aureus). In Experiment 1, the optimum dietary Cu levels were quantified for the species previously with organic (Cu amino acid complex) and inorganic Cu (CuSO4) as 10 mg Cu/kg and 4 mg Cu/kg, respectively. Casein-basal diet with 15 g/kg phytic acid was supplemented with optimum, 5×optimum and 10×optimum of organic Cu or inorganic Cu. Basal diet without phytic acid but supplemented with optimum levels of organic or inorganic Cu were also included for comparison. Total of eight experimental diets were each fed to triplicate groups of juvenile tilapia (mean initial body weight 0.99±0.01 g) for 8 weeks. Growth performance, whole body composition, immune responses, plasma ceruloplasmin activity and muscle and vertebral mineral concentrations were not affected (P>0.05) by dietary phytic acid supplementation, Cu sources or levels. In the organic Cu supplemented groups, fish fed the diet with 10×optimum Cu showed lower survival, hepatosomatic index (HSI) and hematocrit (Hct) than other dietary treatments. Whole body and hepatic Cu concentrations increased with the increment of dietary Cu levels regardless of Cu sources. Result indicated that dietary phytic acid (15 g/kg) did not affect growth performance, physiological responses and tissue mineral concentrations of tilapia. In Experiment 2, soybean meal-basal diet (containing 6.9 mg Cu/kg and 15.8 g/kg of phytic acid) were supplemented with 4, 8 and 12 mg Cu/kg of organic or inorganic Cu. Basal diet without Cu supplementation was used as control. Total of seven experiment diets were each fed to triplicate groups of juvenile tilapia (mean initial body weight 0.73±0.01 g) for 8 weeks. There were no significant difference in growth performance, hematological indices, immune responses, plasma ceruloplasmin activity, whole body composition and hepatic Cu concentration of tilapia regardless of Cu sources or levels. Whole body Cu concentration was not affected by dietary Cu sources, but increased with increasing dietary Cu levels. Results indicated that the phytic acid derived from soybean meal did not influence the utilization of organic and inorganic Cu by tilapia. The Cu concentration in soybean meal-basal diet (6.9 mg Cu/kg) can meet the Cu requirement for tilapia. Overall of the two experiments, dietary phytic acid does not affect the utilization of organic and inorganic Cu by tilapia.

並列關鍵字

Tilapia ； Phytic acid ； Organic copper ； Inorganic copper

參考文獻

Huang, S.C., Huang, C.H., 2012. Zinc requirements of soft-shelled turtles, Pelodiscus sinensis, fed diets containing phytic acid. J. Fish. Soc. Taiwan 39, 78-85.

Aoyagi, S., Baker, D.H., 1994. Copper-amino acid complexes are partially protected against inhibitory effects of L-cysteine and L-ascorbic acid on copper absorption in chicks. J. Nutr. 124, 388-395.

Apines-Amar, M.J.S., Satoh, S., Kiron, V., Watanabe, T., Fujita, S., 2003. Bioavailability and tissue distribution of amino acid-chelated trace elements in rainbow trout Oncorhynchus mykiss. Fish. Sci. 69, 722-730.

Apines-Amar, M.J.S., Satoh, S., Caipang, C.M.A., Kiron, V., Watanabe, T., Aoki, T., 2004. Amino acid-chelate: a better source of Zn, Mn and Cu for rainbow trout, Oncorhynchus mykiss. Aquaculture 240, 345-358.

Arredondo, M., Muñoz, P., Mura, C.V., Núñez, M.T., 2003. DMT1, a physiologically relevant apical Cu1+ transporter of intestinal cells. Am. J. Physiol. Cell Physiol. 284, 1525-1530.