CAJ | 학술논문

在盐度为4、钠钾比为41.6的低盐井水环境下，选取720尾初始体质量为(0.32±0.006) g 的凡纳滨对虾(Litopenaeus vannamei)，随机分成6组，基础饲料中分别添加0、0.3%、0.6%、0.9%、1.2%和1.5%钾离子(以KCl作为钾离子的添加形式，分别记为D0、D1、D2、D3、D4和D5)，探讨饲料中不同钾水平对凡纳滨对虾生长、氮代谢和渗透压调节的影响。结果表明，随着饲料钾水平的增加，凡纳滨对虾的增重率呈先升高后降低趋势， D2组最高(P<0.05)，但与对照组相比不显著，蛋白质效率以D1组显著最高。体钾含量在各处理组之间呈现出显著差异，以D1组最高， D5组最低(P<0.05)。同时凡纳滨对虾的耗氧率和排氨率随饲料中钾含量的增加均呈显著的先降低后上升趋势(P<0.05)，其中排氨率以D2组最低，耗氧率以D3组最低，且均显著低于对照组。血清精氨酸酶活性呈峰值变化趋势，其中以D1组最低(P<0.05)。各实验组血清Na+和Cl-含量呈显著的先降低后升高的趋势(P<0.05)， Na+含量以D1组最低， Cl-含量以D1和D2组最低。而鳃丝Na+-K+-ATPase活性呈显著先升高后降低的趋势(P<0.05)， D3组最高， D2组与D3组无显著差异(P>0.05)。血清总蛋白含量呈显著升高趋势。D2组血蓝蛋白含量最高，渗透压和血清 K+含量在各组间无显著差异(P>0.05)。以生长、氮代谢、渗透调节相关指标为判据：凡纳滨对虾饲料中添加0.3%~0.6%(含钾量：0.96~1.26 g/100g饲料)的钾有利于低盐环境下对虾对饲料蛋白的利用及生理代谢平衡，而过高的添加量(1.5%，总含钾量：2.17g/100g饲料)则会影响其生理代谢从而抑制生长。
재염도위4、납갑비위41.6적저염정수배경하，선취720미초시체질량위(0.32±0.006) g 적범납빈대하(Litopenaeus vannamei)，수궤분성6조，기출사료중분별첨가0、0.3%、0.6%、0.9%、1.2%화1.5%갑리자(이KCl작위갑리자적첨가형식，분별기위D0、D1、D2、D3、D4화D5)，탐토사료중불동갑수평대범납빈대하생장、담대사화삼투압조절적영향。결과표명，수착사료갑수평적증가，범납빈대하적증중솔정선승고후강저추세， D2조최고(P<0.05)，단여대조조상비불현저，단백질효솔이D1조현저최고。체갑함량재각처리조지간정현출현저차이，이D1조최고， D5조최저(P<0.05)。동시범납빈대하적모양솔화배안솔수사료중갑함량적증가균정현저적선강저후상승추세(P<0.05)，기중배안솔이D2조최저，모양솔이D3조최저，차균현저저우대조조。혈청정안산매활성정봉치변화추세，기중이D1조최저(P<0.05)。각실험조혈청Na+화Cl-함량정현저적선강저후승고적추세(P<0.05)， Na+함량이D1조최저， Cl-함량이D1화D2조최저。이새사Na+-K+-ATPase활성정현저선승고후강저적추세(P<0.05)， D3조최고， D2조여D3조무현저차이(P>0.05)。혈청총단백함량정현저승고추세。D2조혈람단백함량최고，삼투압화혈청 K+함량재각조간무현저차이(P>0.05)。이생장、담대사、삼투조절상관지표위판거：범납빈대하사료중첨가0.3%~0.6%(함갑량：0.96~1.26 g/100g사료)적갑유리우저염배경하대하대사료단백적이용급생리대사평형，이과고적첨가량(1.5%，총함갑량：2.17g/100g사료)칙회영향기생리대사종이억제생장。
An 8-week feeding trial was conducted to evaluate the effects of dietary potassium (K+) on growth perform-ance, nitrogen metabolism and osmoregulation of the Pacific white shrimp (Litopenaeus vannamei) reared in low-salinity well-water (4 ppt) with a Na+/K+of 41.6. A total of 720 juvenile shrimps, with an initial body weight of 0.372 g ± 0.006 g, were randomly divided into six groups. Six experimental semi-purified diets were formulated, con-taining 0.59, 0.96, 1.26, 1.48, 1.74 and 2.17 g (K+)/(100 g diet) as feeding treatments and designated as D0, D1, D2, D3, D4 and D5 group, respectively. After a 56-day feeding trial, the results showed that the weight gain rate (WGR) of shrimps fed with D2 [1.26 g(K+)/(100 g diet) ] was the highest (P<0.05), but there was no significant difference be-tween D2 and D0 (control). The protein efficiency ratio (PER) of D1 showed the highest value among all treatments (P<0.05). There were no significant differences in body moisture, crude fat, ash and protein content (P>0.05) among all treatments. However, body potassium content in D1 had the significantly highest value and D5 the lowest in all treat-ments (P<0.05). As dietary K+increased, the oxygen consumption rate of shrimps fed with the 1.48 g (K+)/(100 g diet) (D3 group) had the significantly lowest value (P<0.05), while the ammonia-N excretion rate of D2 was also the signifi-cantly lowest (P<0.05). The D1 diet group had the significantly lowest arginase activity (P<0.05). However, there were no significant differences in hemolymph ammonia, urea or uric acid levels among all treatment groups (P>0.05). Hemolymph Na+and Cl-values decreased and then increased significantly with increased dietary K+(P<0.05), with the D1 group having the lowest value. Gill Na+-K+-ATPase activity revealed a reverse trend and shrimps fed with the 1.48( K+)/(100 g diet) (D3 group) had a relatively higher value than other treatment groups (P<0.05). With increasing dietary K+, hemocyanin levels tended to increase and then decrease significantly (P<0.05). There were no significant differences between hemolymph osmolarity or potassium (P>0.05). In conclusion, a total of 0.96-1.26 g (K+)/(100 g diet) can improve dietary protein utilization and maintain a balance in the nitrogen metabolism and osmoregulation of L. vannamei reared in low-salinity well-water with a Na+/K+of 41.6. Excessive supplementation of potassium [1.5%, total 2.17 g (K+)/(100 g diet)] may disturb metabolism and limit the growth of L. vannamei.