The Effect of Fortification of Potassium and Magnesium in the Diet and Culture Water on Growth, Survival and Osmoregulation of Pacific White Shrimp, Litopenaeus vannamei Reared in Inland Ground Saline Water

Özet

A 60 day trial was conducted to evaluate the effect of dietary supplementation of graded levels of potassium (K+) andmagnesium (Mg2+) on Litopenaeus vannamei reared using IGSW (inland ground saline water, 10 ppt). Two different types ofwaters, IGSW without ionic fortification (R-IGSW, R-raw) and IGSW fortified with K+ & Mg2+ (F-IGSW, F-fortified) withequivalent salinity sea water was used. Four experimental diets with graded levels of K+ & Mg2+: F1 (5 g KCl & 150 mgMgCl2 kg-1 of feed); F2 (10 g KCl & 300 mg MgCl2 kg-1 of feed); F3 (15 g KCl & 450 mg MgCl2 kg-1 of feed) and F4 (withno ionic amendment) were tested in the trial, for each of the two types of water. A significant improvement in the growth andsurvival has been observed in the groups fortified with K+ & Mg2+ in the feed (P<0.05) irrespective of the potassium andmagnesium levels in the water. No significant difference in osmoregulatory capacity, serum and water osmolality and Na+ K+-ATPase activity of gill despite the significant variation (P<0.05) in serum K+, Na+, Mg2+ and Ca2+ levels were observedamong different treatments. It is concluded that growth and survival of L. vannamei can be enhanced by supplementing thedeficient ions such as K+ (5 g kg-1) and Mg2+(150 mg Kg-1) through diet as well as in the water simultaneously.