<div>Background: Tor putitora is distributed in the entire northeast Himalayan region. The declining population of Tor putitora in natural waters has major concern to its fishery. The knowledge of semen characteristics is helpful in the selection of good quality semen for artificial fertilization thus have a role in fishery development. The current study aimed to determine the physical and biochemical composition of seminal plasma of Tor putitora. 
 
Methods: The semen samples were collected by stripping the ripe male brooders procured from the natural habitat. The sperm motility, sperm density, spermatocrit value and osmolality were determined for physical characteristics of semen. Haemocytometric method was used for sperm density. The seminal plasma was separated by centrifugation for the determination of ionic and organic component of semen through atomic absorption spectrometer. 
 
Result: The semen of T. putitora has shown species-specific features of sperm density (1.712 &plusmn; 0.18 &times; 109 ml-1), spermatocrit (62.96 &plusmn; 2.63 %) and sperm motility duration (48.16 &plusmn; 1.68 s). The Na2+ (102.06 &plusmn; 5.115 mM l-l) and K+ (51.66 &plusmn; 3.205 mM l-l) are predominating ions among the other inorganic constituents (Ca2+: 1.38 &plusmn; 0.304 mg dl-1, Mg2+: 0.86 &plusmn; 0.261 mg l-l, phosphate: 4.00 &plusmn; 1.102 mg dl-1, Cu2+: 0.004 &plusmn; 0.001 mg l-l and Zn2+: 0.062 &plusmn; 0.005 mg l-l) of the seminal plasma. The organic constituents of seminal plasma contained - Glucose: 9.6 &plusmn; 0.678 mg dl-1, Cholesterol: 21.0 &plusmn; 1.049 mg dl-1, Triglycerides: 11.0 &plusmn; 0.316 mg dl-1, Urea: 12.6 &plusmn; 1.7206 mg dl-1 and Uric acid: 0.5 &plusmn; 0.10 mg dl-1. The Osmolality (256.8 &plusmn; 31.940 mOsmol kg-1), pH (7.34 &plusmn; 0.04) and ionic composition of semen seem to be the most important factor responsible for inhibition or activation of sperm motility. A high significant positive relationship (r=0.807, P&lt;0.01) was found between sperm density and spermatocrit suggests the use of regression equation for quick and reliable estimation of sperm concentration in Tor putitora. The study is helpful in the selection of high-quality male spawners and provides baseline information for the development of extenders and dilutants for the preservation of viable semen.</div>

<div>A Study on the Physical and Biochemical Characteristics of Semen of Tor putitora- An Endangered Fish Species in Himalayan Water</div>

Background: A 60-day experiment was conducted to evaluate the combined effect of salinity and Ca2+: Mg2+ ratio on the nutrient profile, physiological responses, and clinical signs of Penaeus vannamei reared in inland saline ground water.&nbsp; 
 
Methods: The study used three different salinities viz. T1 (5 ppt), T2 (10 ppt) and T3 (15 ppt) with four different levels of Ca2+: Mg2+ ratios such as 1:1, 1:2, 1:3, and 1:4. A total of 720 healthy post larvae of P. vannamei (mean body weight of 3.70&plusmn;0.02 g) were stocked (20 shrimp/tank) in 36 circular plastic tanks (100 L capacity each). Each treatment was triplicated following the 3 &times; 4 factorial design. 
 
Result: A significant increase of protein and ash contents and decrease of moisture content were noticed with increasing salinity. The study found no significant difference in the carbohydrate and crude lipid content of P. vannamei. A linear relationship between salinity and serum osmolality was observed which indicated significant increase of osmoregulatory capacity with increasing salinity. The treatment groups fortified with deficient level of Ca2+: Mg2+ ratio showed prominent changes such as abdominal white muscle on dorsal side and muscle cramps. Based on the results, it can be concluded that the better physiological adoption of P. vannamei was observed in 10 and 15 ppt salinities of ISGW fortified with Ca2+: Mg2+ ratio 1:3.

Effects of Salinity and Ca2+: Mg2+ Ratio on Nutrient Profile, Physiological Responses and Clinical Signs of Penaeus vannamei (Boone, 1931) Reared in Inland Saline Ground Water