方斑东风螺饲料中锌需要量的研究

摘要

This experiment was conducted to determine the dietary zinc (Zn) requirement of spotted babylon, Babylonia areolate. Six doses of 0, 5, 10, 20, 30 and 50 mg/kg Zn from zinc sulfate were supplemented in a basal diet (casein and gelatin were used as protein sources) to prepare 6 experimental diets. In the 6 experimental diets, the Zn levels were 7.1, 10.1, 15. 3, 23. 4, 33. 0 and 54.4 mg/kg, respectively. Each diet was fed one group (each group had 3 replicates and each replicate had 80 spotted babylon) of spotted babylon with an initial body weight of (106. 25 ± 0. 00) mg for 8 weeks. The Zn content in rearing seawater was 5. 74 μg/L. The results showed as follows; the survival rate (SR), feed conversion rate (FCR), protein efficiency rate (PER) and soft body to shell ratio (SB/SR) were not significantly affected by dietary Zn content (P >0. 05). With the increase of dietary Zn content, the weight gain rate (WGR) was significantly increased firstly (P <0. 05) , and then there was no significant difference among all groups when dietary Zn content reached 15. 3 mg/kg (P >0. 05). 2) No significant differences were found in the contents of moisture, crude protein, ether extract and ash in soft body of spotted babylon among all groups (P >0. 05). 3) The soft body Zn content of spotted babylon had a positive correlation with dietary Zn content (P <0. 05, R2 =0. 975 0) , but the shell Zn content was not significantly affected by dietary Zn content (P >0. 05). 4) With the increase of dietary Zn content, the activities of total superoxide dismutase (T-SOD) , copper-zinc superoxide dismutase ( CuZn-SOD) , catalase (CAT) and alkaline phosphatase (AKP) in visceral mass of spotted babylon were significantly increased firstly (P < 0. 05) , and then no significant differences were found in above enzymic activities among all groups when dietary Zn content reached 23. 4 mg/kg (P >0. 05). Using the broken-line model with WGR as the dependent variable, the optimum dietary Zn requirement of spotted babylon is estimated to be 15. 3 mg/kg. Analysis by broken-line of the activities of T-SOD, CuZn-SOD, CAT and AKP in visceral mass indicates that the optimum requirement of juvenile spotted babylon for dietary Zn is 22. 9 to 24. 3 mg/kg.%本试验旨在研究方斑东风螺(Babylonia areolate)对饲料锌的需要量.以硫酸锌为锌源,在以酪蛋白、明胶为主要蛋白质源的基础饲料中分别添加0、5、10、20、30、50 mg/kg的锌,使6种试验饲料中锌含量分别达到7.1、10.1、15.3、23.4、33.0、54.4 mg/kg.每种饲料饲喂1组方斑东风螺,每组3个重复,每个重复80只螺,螺初始体重为(106.25±0.00) mg.试验期8周,养殖水体中锌含量为5.74 μg/L.结果表明:1)饲料锌含量对方斑东风螺饲料系数(FCR)、蛋白质效率(PER)、成活率(SR)和肉壳比(SB/SR)无显著影响(P＞0.05).方斑东风螺增重率(WGR)先随饲料锌含量的升高而显著增加(P＜0.05),当饲料锌含量达到15.3 mg/kg后各组WGR无显著差异(P＞0.05).2)饲料锌含量对方斑东风螺软体部水分、粗蛋白质、粗脂肪和灰分含量无显著影响(P＞0.05).3)方斑东风螺软体部锌含量与饲料锌含量呈正相关关系(P＜0.05,R2=0.975 0),各组方斑东风螺壳中锌含量无显著差异(P＞0.05).4)方斑东风螺内脏团中总超氧化物歧化酶(T-SOD)、铜锌超氧化物歧化酶(CuZn-SOD)、过氧化氢酶(CAT)和碱性磷酸酶(AKP)活力先随饲料锌含量的升高而显著增加(P＜0.05),当饲料锌含量达到23.4 mg/kg后上述酶活力各组间均无显著差异(P＞0.05).以WGR为指标,通过折线模型分析得出方斑东风螺对饲料锌的最适需要量为15.3 mg/kg；以内脏团中T-SOD、CuZn-SOD、CAT和AKP活力为指标,通过折线模型分析得出方斑东风螺对饲料锌的最适需要量为22.9～24.3 mg/kg.